dmaengine: qcom: Add GPI dma driver

This controller provides DMAengine capabilities for a variety of peripheral
buses such as I2C, UART, and SPI. By using GPI dmaengine driver, bus
drivers can use a standardize interface that is protocol independent to
transfer data between memory and peripheral.

Link: https://lore.kernel.org/r/20201109085450.24843-4-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

3 files changed, 2316 insertions, 0 deletions

diff --git a/drivers/dma/qcom/Kconfig b/drivers/dma/qcom/Kconfig
index 0389d60d2604..365f94eb3b08 100644
--- a/drivers/dma/qcom/Kconfig
+++ b/drivers/dma/qcom/Kconfig
@@ -19,6 +19,18 @@ config QCOM_BAM_DMA
 	  Enable support for the QCOM BAM DMA controller.  This controller
 	  provides DMA capabilities for a variety of on-chip devices.
 
+config QCOM_GPI_DMA
+        tristate "Qualcomm Technologies GPI DMA support"
+        depends on ARCH_QCOM
+        select DMA_ENGINE
+        select DMA_VIRTUAL_CHANNELS
+        help
+          Enable support for the QCOM GPI DMA controller. This controller
+          provides DMA capabilities for a variety of peripheral buses such
+          as I2C, UART, and SPI. By using GPI dmaengine driver, bus drivers
+          can use a standardize interface that is protocol independent to
+          transfer data between DDR and peripheral.
+
 config QCOM_HIDMA_MGMT
 	tristate "Qualcomm Technologies HIDMA Management support"
 	select DMA_ENGINE
diff --git a/drivers/dma/qcom/Makefile b/drivers/dma/qcom/Makefile
index 346e643fbb6d..50f1e7014693 100644
--- a/drivers/dma/qcom/Makefile
+++ b/drivers/dma/qcom/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_QCOM_ADM) += qcom_adm.o
 obj-$(CONFIG_QCOM_BAM_DMA) += bam_dma.o
+obj-$(CONFIG_QCOM_GPI_DMA) += gpi.o
 obj-$(CONFIG_QCOM_HIDMA_MGMT) += hdma_mgmt.o
 hdma_mgmt-objs	 := hidma_mgmt.o hidma_mgmt_sys.o
 obj-$(CONFIG_QCOM_HIDMA) +=  hdma.o
diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c
new file mode 100644
index 000000000000..d2334f535de2
--- /dev/null
+++ b/drivers/dma/qcom/gpi.c
@@ -0,0 +1,2303 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2020, Linaro Limited
+ */
+
+#include <dt-bindings/dma/qcom-gpi.h>
+#include <linux/bitfield.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/dma/qcom-gpi-dma.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include "../dmaengine.h"
+#include "../virt-dma.h"
+
+#define TRE_TYPE_DMA		0x10
+#define TRE_TYPE_GO		0x20
+#define TRE_TYPE_CONFIG0	0x22
+
+/* TRE flags */
+#define TRE_FLAGS_CHAIN		BIT(0)
+#define TRE_FLAGS_IEOB		BIT(8)
+#define TRE_FLAGS_IEOT		BIT(9)
+#define TRE_FLAGS_BEI		BIT(10)
+#define TRE_FLAGS_LINK		BIT(11)
+#define TRE_FLAGS_TYPE		GENMASK(23, 16)
+
+/* SPI CONFIG0 WD0 */
+#define TRE_SPI_C0_WORD_SZ	GENMASK(4, 0)
+#define TRE_SPI_C0_LOOPBACK	BIT(8)
+#define TRE_SPI_C0_CS		BIT(11)
+#define TRE_SPI_C0_CPHA		BIT(12)
+#define TRE_SPI_C0_CPOL		BIT(13)
+#define TRE_SPI_C0_TX_PACK	BIT(24)
+#define TRE_SPI_C0_RX_PACK	BIT(25)
+
+/* CONFIG0 WD2 */
+#define TRE_C0_CLK_DIV		GENMASK(11, 0)
+#define TRE_C0_CLK_SRC		GENMASK(19, 16)
+
+/* SPI GO WD0 */
+#define TRE_SPI_GO_CMD		GENMASK(4, 0)
+#define TRE_SPI_GO_CS		GENMASK(10, 8)
+#define TRE_SPI_GO_FRAG		BIT(26)
+
+/* GO WD2 */
+#define TRE_RX_LEN		GENMASK(23, 0)
+
+/* I2C Config0 WD0 */
+#define TRE_I2C_C0_TLOW		GENMASK(7, 0)
+#define TRE_I2C_C0_THIGH	GENMASK(15, 8)
+#define TRE_I2C_C0_TCYL		GENMASK(23, 16)
+#define TRE_I2C_C0_TX_PACK	BIT(24)
+#define TRE_I2C_C0_RX_PACK      BIT(25)
+
+/* I2C GO WD0 */
+#define TRE_I2C_GO_CMD          GENMASK(4, 0)
+#define TRE_I2C_GO_ADDR		GENMASK(14, 8)
+#define TRE_I2C_GO_STRETCH	BIT(26)
+
+/* DMA TRE */
+#define TRE_DMA_LEN		GENMASK(23, 0)
+
+/* Register offsets from gpi-top */
+#define GPII_n_CH_k_CNTXT_0_OFFS(n, k)	(0x20000 + (0x4000 * (n)) + (0x80 * (k)))
+#define GPII_n_CH_k_CNTXT_0_EL_SIZE	GENMASK(31, 24)
+#define GPII_n_CH_k_CNTXT_0_CHSTATE	GENMASK(23, 20)
+#define GPII_n_CH_k_CNTXT_0_ERIDX	GENMASK(18, 14)
+#define GPII_n_CH_k_CNTXT_0_DIR		BIT(3)
+#define GPII_n_CH_k_CNTXT_0_PROTO	GENMASK(2, 0)
+
+#define GPII_n_CH_k_CNTXT_0(el_size, erindex, dir, chtype_proto)  \
+	(FIELD_PREP(GPII_n_CH_k_CNTXT_0_EL_SIZE, el_size)	| \
+	 FIELD_PREP(GPII_n_CH_k_CNTXT_0_ERIDX, erindex)		| \
+	 FIELD_PREP(GPII_n_CH_k_CNTXT_0_DIR, dir)		| \
+	 FIELD_PREP(GPII_n_CH_k_CNTXT_0_PROTO, chtype_proto))
+
+#define GPI_CHTYPE_DIR_IN	(0)
+#define GPI_CHTYPE_DIR_OUT	(1)
+
+#define GPI_CHTYPE_PROTO_GPI	(0x2)
+
+#define GPII_n_CH_k_DOORBELL_0_OFFS(n, k)	(0x22000 + (0x4000 * (n)) + (0x8 * (k)))
+#define GPII_n_CH_CMD_OFFS(n)			(0x23008 + (0x4000 * (n)))
+#define GPII_n_CH_CMD_OPCODE			GENMASK(31, 24)
+#define GPII_n_CH_CMD_CHID			GENMASK(7, 0)
+#define GPII_n_CH_CMD(opcode, chid)				 \
+		     (FIELD_PREP(GPII_n_CH_CMD_OPCODE, opcode) | \
+		      FIELD_PREP(GPII_n_CH_CMD_CHID, chid))
+
+#define GPII_n_CH_CMD_ALLOCATE		(0)
+#define GPII_n_CH_CMD_START		(1)
+#define GPII_n_CH_CMD_STOP		(2)
+#define GPII_n_CH_CMD_RESET		(9)
+#define GPII_n_CH_CMD_DE_ALLOC		(10)
+#define GPII_n_CH_CMD_UART_SW_STALE	(32)
+#define GPII_n_CH_CMD_UART_RFR_READY	(33)
+#define GPII_n_CH_CMD_UART_RFR_NOT_READY (34)
+
+/* EV Context Array */
+#define GPII_n_EV_CH_k_CNTXT_0_OFFS(n, k) (0x21000 + (0x4000 * (n)) + (0x80 * (k)))
+#define GPII_n_EV_k_CNTXT_0_EL_SIZE	GENMASK(31, 24)
+#define GPII_n_EV_k_CNTXT_0_CHSTATE	GENMASK(23, 20)
+#define GPII_n_EV_k_CNTXT_0_INTYPE	BIT(16)
+#define GPII_n_EV_k_CNTXT_0_CHTYPE	GENMASK(3, 0)
+
+#define GPII_n_EV_k_CNTXT_0(el_size, inttype, chtype)		\
+	(FIELD_PREP(GPII_n_EV_k_CNTXT_0_EL_SIZE, el_size) |	\
+	 FIELD_PREP(GPII_n_EV_k_CNTXT_0_INTYPE, inttype)  |	\
+	 FIELD_PREP(GPII_n_EV_k_CNTXT_0_CHTYPE, chtype))
+
+#define GPI_INTTYPE_IRQ		(1)
+#define GPI_CHTYPE_GPI_EV	(0x2)
+
+enum CNTXT_OFFS {
+	CNTXT_0_CONFIG = 0x0,
+	CNTXT_1_R_LENGTH = 0x4,
+	CNTXT_2_RING_BASE_LSB = 0x8,
+	CNTXT_3_RING_BASE_MSB = 0xC,
+	CNTXT_4_RING_RP_LSB = 0x10,
+	CNTXT_5_RING_RP_MSB = 0x14,
+	CNTXT_6_RING_WP_LSB = 0x18,
+	CNTXT_7_RING_WP_MSB = 0x1C,
+	CNTXT_8_RING_INT_MOD = 0x20,
+	CNTXT_9_RING_INTVEC = 0x24,
+	CNTXT_10_RING_MSI_LSB = 0x28,
+	CNTXT_11_RING_MSI_MSB = 0x2C,
+	CNTXT_12_RING_RP_UPDATE_LSB = 0x30,
+	CNTXT_13_RING_RP_UPDATE_MSB = 0x34,
+};
+
+#define GPII_n_EV_CH_k_DOORBELL_0_OFFS(n, k)	(0x22100 + (0x4000 * (n)) + (0x8 * (k)))
+#define GPII_n_EV_CH_CMD_OFFS(n)		(0x23010 + (0x4000 * (n)))
+#define GPII_n_EV_CMD_OPCODE			GENMASK(31, 24)
+#define GPII_n_EV_CMD_CHID			GENMASK(7, 0)
+#define GPII_n_EV_CMD(opcode, chid)				 \
+		     (FIELD_PREP(GPII_n_EV_CMD_OPCODE, opcode) | \
+		      FIELD_PREP(GPII_n_EV_CMD_CHID, chid))
+
+#define GPII_n_EV_CH_CMD_ALLOCATE		(0x00)
+#define GPII_n_EV_CH_CMD_RESET			(0x09)
+#define GPII_n_EV_CH_CMD_DE_ALLOC		(0x0A)
+
+#define GPII_n_CNTXT_TYPE_IRQ_OFFS(n)		(0x23080 + (0x4000 * (n)))
+
+/* mask type register */
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(n)	(0x23088 + (0x4000 * (n)))
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK		GENMASK(6, 0)
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_GENERAL	BIT(6)
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB		BIT(3)
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB		BIT(2)
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL	BIT(1)
+#define GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL	BIT(0)
+
+#define GPII_n_CNTXT_SRC_GPII_CH_IRQ_OFFS(n)	(0x23090 + (0x4000 * (n)))
+#define GPII_n_CNTXT_SRC_EV_CH_IRQ_OFFS(n)	(0x23094 + (0x4000 * (n)))
+
+/* Mask channel control interrupt register */
+#define GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(n)	(0x23098 + (0x4000 * (n)))
+#define GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK	GENMASK(1, 0)
+
+/* Mask event control interrupt register */
+#define GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(n)	(0x2309C + (0x4000 * (n)))
+#define GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK	BIT(0)
+
+#define GPII_n_CNTXT_SRC_CH_IRQ_CLR_OFFS(n)	(0x230A0 + (0x4000 * (n)))
+#define GPII_n_CNTXT_SRC_EV_CH_IRQ_CLR_OFFS(n)	(0x230A4 + (0x4000 * (n)))
+
+/* Mask event interrupt register */
+#define GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(n)	(0x230B8 + (0x4000 * (n)))
+#define GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK	BIT(0)
+
+#define GPII_n_CNTXT_SRC_IEOB_IRQ_CLR_OFFS(n)	(0x230C0 + (0x4000 * (n)))
+#define GPII_n_CNTXT_GLOB_IRQ_STTS_OFFS(n)	(0x23100 + (0x4000 * (n)))
+#define GPI_GLOB_IRQ_ERROR_INT_MSK		BIT(0)
+
+/* GPII specific Global - Enable bit register */
+#define GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(n)	(0x23108 + (0x4000 * (n)))
+#define GPII_n_CNTXT_GLOB_IRQ_CLR_OFFS(n)	(0x23110 + (0x4000 * (n)))
+#define GPII_n_CNTXT_GPII_IRQ_STTS_OFFS(n)	(0x23118 + (0x4000 * (n)))
+
+/* GPII general interrupt - Enable bit register */
+#define GPII_n_CNTXT_GPII_IRQ_EN_OFFS(n)	(0x23120 + (0x4000 * (n)))
+#define GPII_n_CNTXT_GPII_IRQ_EN_BMSK		GENMASK(3, 0)
+
+#define GPII_n_CNTXT_GPII_IRQ_CLR_OFFS(n)	(0x23128 + (0x4000 * (n)))
+
+/* GPII Interrupt Type register */
+#define GPII_n_CNTXT_INTSET_OFFS(n)		(0x23180 + (0x4000 * (n)))
+#define GPII_n_CNTXT_INTSET_BMSK		BIT(0)
+
+#define GPII_n_CNTXT_MSI_BASE_LSB_OFFS(n)	(0x23188 + (0x4000 * (n)))
+#define GPII_n_CNTXT_MSI_BASE_MSB_OFFS(n)	(0x2318C + (0x4000 * (n)))
+#define GPII_n_CNTXT_SCRATCH_0_OFFS(n)		(0x23400 + (0x4000 * (n)))
+#define GPII_n_CNTXT_SCRATCH_1_OFFS(n)		(0x23404 + (0x4000 * (n)))
+
+#define GPII_n_ERROR_LOG_OFFS(n)		(0x23200 + (0x4000 * (n)))
+
+/* QOS Registers */
+#define GPII_n_CH_k_QOS_OFFS(n, k)		(0x2005C + (0x4000 * (n)) + (0x80 * (k)))
+
+/* Scratch registers */
+#define GPII_n_CH_k_SCRATCH_0_OFFS(n, k)	(0x20060 + (0x4000 * (n)) + (0x80 * (k)))
+#define GPII_n_CH_k_SCRATCH_0_SEID		GENMASK(2, 0)
+#define GPII_n_CH_k_SCRATCH_0_PROTO		GENMASK(7, 4)
+#define GPII_n_CH_k_SCRATCH_0_PAIR		GENMASK(20, 16)
+#define GPII_n_CH_k_SCRATCH_0(pair, proto, seid)		\
+			     (FIELD_PREP(GPII_n_CH_k_SCRATCH_0_PAIR, pair)	| \
+			      FIELD_PREP(GPII_n_CH_k_SCRATCH_0_PROTO, proto)	| \
+			      FIELD_PREP(GPII_n_CH_k_SCRATCH_0_SEID, seid))
+#define GPII_n_CH_k_SCRATCH_1_OFFS(n, k)	(0x20064 + (0x4000 * (n)) + (0x80 * (k)))
+#define GPII_n_CH_k_SCRATCH_2_OFFS(n, k)	(0x20068 + (0x4000 * (n)) + (0x80 * (k)))
+#define GPII_n_CH_k_SCRATCH_3_OFFS(n, k)	(0x2006C + (0x4000 * (n)) + (0x80 * (k)))
+
+struct __packed gpi_tre {
+	u32 dword[4];
+};
+
+enum msm_gpi_tce_code {
+	MSM_GPI_TCE_SUCCESS = 1,
+	MSM_GPI_TCE_EOT = 2,
+	MSM_GPI_TCE_EOB = 4,
+	MSM_GPI_TCE_UNEXP_ERR = 16,
+};
+
+#define CMD_TIMEOUT_MS		(250)
+
+#define MAX_CHANNELS_PER_GPII	(2)
+#define GPI_TX_CHAN		(0)
+#define GPI_RX_CHAN		(1)
+#define STATE_IGNORE		(U32_MAX)
+#define EV_FACTOR		(2)
+#define REQ_OF_DMA_ARGS		(5) /* # of arguments required from client */
+#define CHAN_TRES		64
+
+struct __packed xfer_compl_event {
+	u64 ptr;
+	u32 length:24;
+	u8 code;
+	u16 status;
+	u8 type;
+	u8 chid;
+};
+
+struct __packed immediate_data_event {
+	u8 data_bytes[8];
+	u8 length:4;
+	u8 resvd:4;
+	u16 tre_index;
+	u8 code;
+	u16 status;
+	u8 type;
+	u8 chid;
+};
+
+struct __packed qup_notif_event {
+	u32 status;
+	u32 time;
+	u32 count:24;
+	u8 resvd;
+	u16 resvd1;
+	u8 type;
+	u8 chid;
+};
+
+struct __packed gpi_ere {
+	u32 dword[4];
+};
+
+enum GPI_EV_TYPE {
+	XFER_COMPLETE_EV_TYPE = 0x22,
+	IMMEDIATE_DATA_EV_TYPE = 0x30,
+	QUP_NOTIF_EV_TYPE = 0x31,
+	STALE_EV_TYPE = 0xFF,
+};
+
+union __packed gpi_event {
+	struct __packed xfer_compl_event xfer_compl_event;
+	struct __packed immediate_data_event immediate_data_event;
+	struct __packed qup_notif_event qup_notif_event;
+	struct __packed gpi_ere gpi_ere;
+};
+
+enum gpii_irq_settings {
+	DEFAULT_IRQ_SETTINGS,
+	MASK_IEOB_SETTINGS,
+};
+
+enum gpi_ev_state {
+	DEFAULT_EV_CH_STATE = 0,
+	EV_STATE_NOT_ALLOCATED = DEFAULT_EV_CH_STATE,
+	EV_STATE_ALLOCATED,
+	MAX_EV_STATES
+};
+
+static const char *const gpi_ev_state_str[MAX_EV_STATES] = {
+	[EV_STATE_NOT_ALLOCATED] = "NOT ALLOCATED",
+	[EV_STATE_ALLOCATED] = "ALLOCATED",
+};
+
+#define TO_GPI_EV_STATE_STR(_state) (((_state) >= MAX_EV_STATES) ? \
+				    "INVALID" : gpi_ev_state_str[(_state)])
+
+enum gpi_ch_state {
+	DEFAULT_CH_STATE = 0x0,
+	CH_STATE_NOT_ALLOCATED = DEFAULT_CH_STATE,
+	CH_STATE_ALLOCATED = 0x1,
+	CH_STATE_STARTED = 0x2,
+	CH_STATE_STOPPED = 0x3,
+	CH_STATE_STOP_IN_PROC = 0x4,
+	CH_STATE_ERROR = 0xf,
+	MAX_CH_STATES
+};
+
+enum gpi_cmd {
+	GPI_CH_CMD_BEGIN,
+	GPI_CH_CMD_ALLOCATE = GPI_CH_CMD_BEGIN,
+	GPI_CH_CMD_START,
+	GPI_CH_CMD_STOP,
+	GPI_CH_CMD_RESET,
+	GPI_CH_CMD_DE_ALLOC,
+	GPI_CH_CMD_UART_SW_STALE,
+	GPI_CH_CMD_UART_RFR_READY,
+	GPI_CH_CMD_UART_RFR_NOT_READY,
+	GPI_CH_CMD_END = GPI_CH_CMD_UART_RFR_NOT_READY,
+	GPI_EV_CMD_BEGIN,
+	GPI_EV_CMD_ALLOCATE = GPI_EV_CMD_BEGIN,
+	GPI_EV_CMD_RESET,
+	GPI_EV_CMD_DEALLOC,
+	GPI_EV_CMD_END = GPI_EV_CMD_DEALLOC,
+	GPI_MAX_CMD,
+};
+
+#define IS_CHAN_CMD(_cmd) ((_cmd) <= GPI_CH_CMD_END)
+
+static const char *const gpi_cmd_str[GPI_MAX_CMD] = {
+	[GPI_CH_CMD_ALLOCATE] = "CH ALLOCATE",
+	[GPI_CH_CMD_START] = "CH START",
+	[GPI_CH_CMD_STOP] = "CH STOP",
+	[GPI_CH_CMD_RESET] = "CH_RESET",
+	[GPI_CH_CMD_DE_ALLOC] = "DE ALLOC",
+	[GPI_CH_CMD_UART_SW_STALE] = "UART SW STALE",
+	[GPI_CH_CMD_UART_RFR_READY] = "UART RFR READY",
+	[GPI_CH_CMD_UART_RFR_NOT_READY] = "UART RFR NOT READY",
+	[GPI_EV_CMD_ALLOCATE] = "EV ALLOCATE",
+	[GPI_EV_CMD_RESET] = "EV RESET",
+	[GPI_EV_CMD_DEALLOC] = "EV DEALLOC",
+};
+
+#define TO_GPI_CMD_STR(_cmd) (((_cmd) >= GPI_MAX_CMD) ? "INVALID" : \
+				  gpi_cmd_str[(_cmd)])
+
+/*
+ * @DISABLE_STATE: no register access allowed
+ * @CONFIG_STATE:  client has configured the channel
+ * @PREP_HARDWARE: register access is allowed
+ *		   however, no processing EVENTS
+ * @ACTIVE_STATE: channels are fully operational
+ * @PREPARE_TERMINATE: graceful termination of channels
+ *		       register access is allowed
+ * @PAUSE_STATE: channels are active, but not processing any events
+ */
+enum gpi_pm_state {
+	DISABLE_STATE,
+	CONFIG_STATE,
+	PREPARE_HARDWARE,
+	ACTIVE_STATE,
+	PREPARE_TERMINATE,
+	PAUSE_STATE,
+	MAX_PM_STATE
+};
+
+#define REG_ACCESS_VALID(_pm_state) ((_pm_state) >= PREPARE_HARDWARE)
+
+static const char *const gpi_pm_state_str[MAX_PM_STATE] = {
+	[DISABLE_STATE] = "DISABLE",
+	[CONFIG_STATE] = "CONFIG",
+	[PREPARE_HARDWARE] = "PREPARE HARDWARE",
+	[ACTIVE_STATE] = "ACTIVE",
+	[PREPARE_TERMINATE] = "PREPARE TERMINATE",
+	[PAUSE_STATE] = "PAUSE",
+};
+
+#define TO_GPI_PM_STR(_state) (((_state) >= MAX_PM_STATE) ? \
+			      "INVALID" : gpi_pm_state_str[(_state)])
+
+static const struct {
+	enum gpi_cmd gpi_cmd;
+	u32 opcode;
+	u32 state;
+} gpi_cmd_info[GPI_MAX_CMD] = {
+	{
+		GPI_CH_CMD_ALLOCATE,
+		GPII_n_CH_CMD_ALLOCATE,
+		CH_STATE_ALLOCATED,
+	},
+	{
+		GPI_CH_CMD_START,
+		GPII_n_CH_CMD_START,
+		CH_STATE_STARTED,
+	},
+	{
+		GPI_CH_CMD_STOP,
+		GPII_n_CH_CMD_STOP,
+		CH_STATE_STOPPED,
+	},
+	{
+		GPI_CH_CMD_RESET,
+		GPII_n_CH_CMD_RESET,
+		CH_STATE_ALLOCATED,
+	},
+	{
+		GPI_CH_CMD_DE_ALLOC,
+		GPII_n_CH_CMD_DE_ALLOC,
+		CH_STATE_NOT_ALLOCATED,
+	},
+	{
+		GPI_CH_CMD_UART_SW_STALE,
+		GPII_n_CH_CMD_UART_SW_STALE,
+		STATE_IGNORE,
+	},
+	{
+		GPI_CH_CMD_UART_RFR_READY,
+		GPII_n_CH_CMD_UART_RFR_READY,
+		STATE_IGNORE,
+	},
+	{
+		GPI_CH_CMD_UART_RFR_NOT_READY,
+		GPII_n_CH_CMD_UART_RFR_NOT_READY,
+		STATE_IGNORE,
+	},
+	{
+		GPI_EV_CMD_ALLOCATE,
+		GPII_n_EV_CH_CMD_ALLOCATE,
+		EV_STATE_ALLOCATED,
+	},
+	{
+		GPI_EV_CMD_RESET,
+		GPII_n_EV_CH_CMD_RESET,
+		EV_STATE_ALLOCATED,
+	},
+	{
+		GPI_EV_CMD_DEALLOC,
+		GPII_n_EV_CH_CMD_DE_ALLOC,
+		EV_STATE_NOT_ALLOCATED,
+	},
+};
+
+struct gpi_ring {
+	void *pre_aligned;
+	size_t alloc_size;
+	phys_addr_t phys_addr;
+	dma_addr_t dma_handle;
+	void *base;
+	void *wp;
+	void *rp;
+	u32 len;
+	u32 el_size;
+	u32 elements;
+	bool configured;
+};
+
+struct gpi_dev {
+	struct dma_device dma_device;
+	struct device *dev;
+	struct resource *res;
+	void __iomem *regs;
+	void __iomem *ee_base; /*ee register base address*/
+	u32 max_gpii; /* maximum # of gpii instances available per gpi block */
+	u32 gpii_mask; /* gpii instances available for apps */
+	u32 ev_factor; /* ev ring length factor */
+	struct gpii *gpiis;
+};
+
+struct reg_info {
+	char *name;
+	u32 offset;
+	u32 val;
+};
+
+struct gchan {
+	struct virt_dma_chan vc;
+	u32 chid;
+	u32 seid;
+	u32 protocol;
+	struct gpii *gpii;
+	enum gpi_ch_state ch_state;
+	enum gpi_pm_state pm_state;
+	void __iomem *ch_cntxt_base_reg;
+	void __iomem *ch_cntxt_db_reg;
+	void __iomem *ch_cmd_reg;
+	u32 dir;
+	struct gpi_ring ch_ring;
+	void *config;
+};
+
+struct gpii {
+	u32 gpii_id;
+	struct gchan gchan[MAX_CHANNELS_PER_GPII];
+	struct gpi_dev *gpi_dev;
+	int irq;
+	void __iomem *regs; /* points to gpi top */
+	void __iomem *ev_cntxt_base_reg;
+	void __iomem *ev_cntxt_db_reg;
+	void __iomem *ev_ring_rp_lsb_reg;
+	void __iomem *ev_cmd_reg;
+	void __iomem *ieob_clr_reg;
+	struct mutex ctrl_lock;
+	enum gpi_ev_state ev_state;
+	bool configured_irq;
+	enum gpi_pm_state pm_state;
+	rwlock_t pm_lock;
+	struct gpi_ring ev_ring;
+	struct tasklet_struct ev_task; /* event processing tasklet */
+	struct completion cmd_completion;
+	enum gpi_cmd gpi_cmd;
+	u32 cntxt_type_irq_msk;
+	bool ieob_set;
+};
+
+#define MAX_TRE 3
+
+struct gpi_desc {
+	struct virt_dma_desc vd;
+	size_t len;
+	void *db; /* DB register to program */
+	struct gchan *gchan;
+	struct gpi_tre tre[MAX_TRE];
+	u32 num_tre;
+};
+
+static const u32 GPII_CHAN_DIR[MAX_CHANNELS_PER_GPII] = {
+	GPI_CHTYPE_DIR_OUT, GPI_CHTYPE_DIR_IN
+};
+
+static irqreturn_t gpi_handle_irq(int irq, void *data);
+static void gpi_ring_recycle_ev_element(struct gpi_ring *ring);
+static int gpi_ring_add_element(struct gpi_ring *ring, void **wp);
+static void gpi_process_events(struct gpii *gpii);
+
+static inline struct gchan *to_gchan(struct dma_chan *dma_chan)
+{
+	return container_of(dma_chan, struct gchan, vc.chan);
+}
+
+static inline struct gpi_desc *to_gpi_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct gpi_desc, vd);
+}
+
+static inline phys_addr_t to_physical(const struct gpi_ring *const ring,
+				      void *addr)
+{
+	return ring->phys_addr + (addr - ring->base);
+}
+
+static inline void *to_virtual(const struct gpi_ring *const ring, phys_addr_t addr)
+{
+	return ring->base + (addr - ring->phys_addr);
+}
+
+static inline u32 gpi_read_reg(struct gpii *gpii, void __iomem *addr)
+{
+	return readl_relaxed(addr);
+}
+
+static inline void gpi_write_reg(struct gpii *gpii, void __iomem *addr, u32 val)
+{
+	writel_relaxed(val, addr);
+}
+
+/* gpi_write_reg_field - write to specific bit field */
+static inline void gpi_write_reg_field(struct gpii *gpii, void __iomem *addr,
+				       u32 mask, u32 shift, u32 val)
+{
+	u32 tmp = gpi_read_reg(gpii, addr);
+
+	tmp &= ~mask;
+	val = tmp | ((val << shift) & mask);
+	gpi_write_reg(gpii, addr, val);
+}
+
+static inline void
+gpi_update_reg(struct gpii *gpii, u32 offset, u32 mask, u32 val)
+{
+	void __iomem *addr = gpii->regs + offset;
+	u32 tmp = gpi_read_reg(gpii, addr);
+
+	tmp &= ~mask;
+	tmp |= u32_encode_bits(val, mask);
+
+	gpi_write_reg(gpii, addr, tmp);
+}
+
+static void gpi_disable_interrupts(struct gpii *gpii)
+{
+	gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_GPII_IRQ_EN_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_GPII_IRQ_EN_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_GPII_IRQ_EN_BMSK, 0);
+	gpi_update_reg(gpii, GPII_n_CNTXT_INTSET_OFFS(gpii->gpii_id),
+		       GPII_n_CNTXT_INTSET_BMSK, 0);
+
+	gpii->cntxt_type_irq_msk = 0;
+	devm_free_irq(gpii->gpi_dev->dev, gpii->irq, gpii);
+	gpii->configured_irq = false;
+}
+
+/* configure and enable interrupts */
+static int gpi_config_interrupts(struct gpii *gpii, enum gpii_irq_settings settings, bool mask)
+{
+	const u32 enable = (GPII_n_CNTXT_TYPE_IRQ_MSK_GENERAL |
+			      GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB |
+			      GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB |
+			      GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL |
+			      GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL);
+	int ret;
+
+	if (!gpii->configured_irq) {
+		ret = devm_request_irq(gpii->gpi_dev->dev, gpii->irq,
+				       gpi_handle_irq, IRQF_TRIGGER_HIGH,
+				       "gpi-dma", gpii);
+		if (ret < 0) {
+			dev_err(gpii->gpi_dev->dev, "error request irq:%d ret:%d\n",
+				gpii->irq, ret);
+			return ret;
+		}
+	}
+
+	if (settings == MASK_IEOB_SETTINGS) {
+		/*
+		 * GPII only uses one EV ring per gpii so we can globally
+		 * enable/disable IEOB interrupt
+		 */
+		if (mask)
+			gpii->cntxt_type_irq_msk |= GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB;
+		else
+			gpii->cntxt_type_irq_msk &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB);
+		gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, gpii->cntxt_type_irq_msk);
+	} else {
+		gpi_update_reg(gpii, GPII_n_CNTXT_TYPE_IRQ_MSK_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_TYPE_IRQ_MSK_BMSK, enable);
+		gpi_update_reg(gpii, GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK,
+			       GPII_n_CNTXT_SRC_IEOB_IRQ_MSK_BMSK);
+		gpi_update_reg(gpii, GPII_n_CNTXT_SRC_CH_IRQ_MSK_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK,
+			       GPII_n_CNTXT_SRC_CH_IRQ_MSK_BMSK);
+		gpi_update_reg(gpii, GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK,
+			       GPII_n_CNTXT_SRC_EV_CH_IRQ_MSK_BMSK);
+		gpi_update_reg(gpii, GPII_n_CNTXT_GLOB_IRQ_EN_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_GPII_IRQ_EN_BMSK,
+			       GPII_n_CNTXT_GPII_IRQ_EN_BMSK);
+		gpi_update_reg(gpii, GPII_n_CNTXT_GPII_IRQ_EN_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_GPII_IRQ_EN_BMSK, GPII_n_CNTXT_GPII_IRQ_EN_BMSK);
+		gpi_update_reg(gpii, GPII_n_CNTXT_MSI_BASE_LSB_OFFS(gpii->gpii_id), U32_MAX, 0);
+		gpi_update_reg(gpii, GPII_n_CNTXT_MSI_BASE_MSB_OFFS(gpii->gpii_id), U32_MAX, 0);
+		gpi_update_reg(gpii, GPII_n_CNTXT_SCRATCH_0_OFFS(gpii->gpii_id), U32_MAX, 0);
+		gpi_update_reg(gpii, GPII_n_CNTXT_SCRATCH_1_OFFS(gpii->gpii_id), U32_MAX, 0);
+		gpi_update_reg(gpii, GPII_n_CNTXT_INTSET_OFFS(gpii->gpii_id),
+			       GPII_n_CNTXT_INTSET_BMSK, 1);
+		gpi_update_reg(gpii, GPII_n_ERROR_LOG_OFFS(gpii->gpii_id), U32_MAX, 0);
+
+		gpii->cntxt_type_irq_msk = enable;
+	}
+
+	gpii->configured_irq = true;
+	return 0;
+}
+
+/* Sends gpii event or channel command */
+static int gpi_send_cmd(struct gpii *gpii, struct gchan *gchan,
+			enum gpi_cmd gpi_cmd)
+{
+	u32 chid = MAX_CHANNELS_PER_GPII;
+	unsigned long timeout;
+	void __iomem *cmd_reg;
+	u32 cmd;
+
+	if (gpi_cmd >= GPI_MAX_CMD)
+		return -EINVAL;
+	if (IS_CHAN_CMD(gpi_cmd))
+		chid = gchan->chid;
+
+	dev_dbg(gpii->gpi_dev->dev,
+		"sending cmd: %s:%u\n", TO_GPI_CMD_STR(gpi_cmd), chid);
+
+	/* send opcode and wait for completion */
+	reinit_completion(&gpii->cmd_completion);
+	gpii->gpi_cmd = gpi_cmd;
+
+	cmd_reg = IS_CHAN_CMD(gpi_cmd) ? gchan->ch_cmd_reg : gpii->ev_cmd_reg;
+	cmd = IS_CHAN_CMD(gpi_cmd) ? GPII_n_CH_CMD(gpi_cmd_info[gpi_cmd].opcode, chid) :
+				     GPII_n_EV_CMD(gpi_cmd_info[gpi_cmd].opcode, 0);
+	gpi_write_reg(gpii, cmd_reg, cmd);
+	timeout = wait_for_completion_timeout(&gpii->cmd_completion,
+					      msecs_to_jiffies(CMD_TIMEOUT_MS));
+	if (!timeout) {
+		dev_err(gpii->gpi_dev->dev, "cmd: %s completion timeout:%u\n",
+			TO_GPI_CMD_STR(gpi_cmd), chid);
+		return -EIO;
+	}
+
+	/* confirm new ch state is correct , if the cmd is a state change cmd */
+	if (gpi_cmd_info[gpi_cmd].state == STATE_IGNORE)
+		return 0;
+
+	if (IS_CHAN_CMD(gpi_cmd) && gchan->ch_state == gpi_cmd_info[gpi_cmd].state)
+		return 0;
+
+	if (!IS_CHAN_CMD(gpi_cmd) && gpii->ev_state == gpi_cmd_info[gpi_cmd].state)
+		return 0;
+
+	return -EIO;
+}
+
+/* program transfer ring DB register */
+static inline void gpi_write_ch_db(struct gchan *gchan,
+				   struct gpi_ring *ring, void *wp)
+{
+	struct gpii *gpii = gchan->gpii;
+	phys_addr_t p_wp;
+
+	p_wp = to_physical(ring, wp);
+	gpi_write_reg(gpii, gchan->ch_cntxt_db_reg, p_wp);
+}
+
+/* program event ring DB register */
+static inline void gpi_write_ev_db(struct gpii *gpii,
+				   struct gpi_ring *ring, void *wp)
+{
+	phys_addr_t p_wp;
+
+	p_wp = ring->phys_addr + (wp - ring->base);
+	gpi_write_reg(gpii, gpii->ev_cntxt_db_reg, p_wp);
+}
+
+/* process transfer completion interrupt */
+static void gpi_process_ieob(struct gpii *gpii)
+{
+	gpi_write_reg(gpii, gpii->ieob_clr_reg, BIT(0));
+
+	gpi_config_interrupts(gpii, MASK_IEOB_SETTINGS, 0);
+	tasklet_hi_schedule(&gpii->ev_task);
+}
+
+/* process channel control interrupt */
+static void gpi_process_ch_ctrl_irq(struct gpii *gpii)
+{
+	u32 gpii_id = gpii->gpii_id;
+	u32 offset = GPII_n_CNTXT_SRC_GPII_CH_IRQ_OFFS(gpii_id);
+	u32 ch_irq = gpi_read_reg(gpii, gpii->regs + offset);
+	struct gchan *gchan;
+	u32 chid, state;
+
+	/* clear the status */
+	offset = GPII_n_CNTXT_SRC_CH_IRQ_CLR_OFFS(gpii_id);
+	gpi_write_reg(gpii, gpii->regs + offset, (u32)ch_irq);
+
+	for (chid = 0; chid < MAX_CHANNELS_PER_GPII; chid++) {
+		if (!(BIT(chid) & ch_irq))
+			continue;
+
+		gchan = &gpii->gchan[chid];
+		state = gpi_read_reg(gpii, gchan->ch_cntxt_base_reg +
+				     CNTXT_0_CONFIG);
+		state = FIELD_GET(GPII_n_CH_k_CNTXT_0_CHSTATE, state);
+
+		/*
+		 * CH_CMD_DEALLOC cmd always successful. However cmd does
+		 * not change hardware status. So overwriting software state
+		 * to default state.
+		 */
+		if (gpii->gpi_cmd == GPI_CH_CMD_DE_ALLOC)
+			state = DEFAULT_CH_STATE;
+		gchan->ch_state = state;
+
+		/*
+		 * Triggering complete all if ch_state is not a stop in process.
+		 * Stop in process is a transition state and we will wait for
+		 * stop interrupt before notifying.
+		 */
+		if (gchan->ch_state != CH_STATE_STOP_IN_PROC)
+			complete_all(&gpii->cmd_completion);
+	}
+}
+
+/* processing gpi general error interrupts */
+static void gpi_process_gen_err_irq(struct gpii *gpii)
+{
+	u32 gpii_id = gpii->gpii_id;
+	u32 offset = GPII_n_CNTXT_GPII_IRQ_STTS_OFFS(gpii_id);
+	u32 irq_stts = gpi_read_reg(gpii, gpii->regs + offset);
+
+	/* clear the status */
+	dev_dbg(gpii->gpi_dev->dev, "irq_stts:0x%x\n", irq_stts);
+
+	/* Clear the register */
+	offset = GPII_n_CNTXT_GPII_IRQ_CLR_OFFS(gpii_id);
+	gpi_write_reg(gpii, gpii->regs + offset, irq_stts);
+}
+
+/* processing gpi level error interrupts */
+static void gpi_process_glob_err_irq(struct gpii *gpii)
+{
+	u32 gpii_id = gpii->gpii_id;
+	u32 offset = GPII_n_CNTXT_GLOB_IRQ_STTS_OFFS(gpii_id);
+	u32 irq_stts = gpi_read_reg(gpii, gpii->regs + offset);
+
+	offset = GPII_n_CNTXT_GLOB_IRQ_CLR_OFFS(gpii_id);
+	gpi_write_reg(gpii, gpii->regs + offset, irq_stts);
+
+	/* only error interrupt should be set */
+	if (irq_stts & ~GPI_GLOB_IRQ_ERROR_INT_MSK) {
+		dev_err(gpii->gpi_dev->dev, "invalid error status:0x%x\n", irq_stts);
+		return;
+	}
+
+	offset = GPII_n_ERROR_LOG_OFFS(gpii_id);
+	gpi_write_reg(gpii, gpii->regs + offset, 0);
+}
+
+/* gpii interrupt handler */
+static irqreturn_t gpi_handle_irq(int irq, void *data)
+{
+	struct gpii *gpii = data;
+	u32 gpii_id = gpii->gpii_id;
+	u32 type, offset;
+	unsigned long flags;
+
+	read_lock_irqsave(&gpii->pm_lock, flags);
+
+	/*
+	 * States are out of sync to receive interrupt
+	 * while software state is in DISABLE state, bailing out.
+	 */
+	if (!REG_ACCESS_VALID(gpii->pm_state)) {
+		dev_err(gpii->gpi_dev->dev, "receive interrupt while in %s state\n",
+			TO_GPI_PM_STR(gpii->pm_state));
+		goto exit_irq;
+	}
+
+	offset = GPII_n_CNTXT_TYPE_IRQ_OFFS(gpii->gpii_id);
+	type = gpi_read_reg(gpii, gpii->regs + offset);
+
+	do {
+		/* global gpii error */
+		if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB) {
+			gpi_process_glob_err_irq(gpii);
+			type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_GLOB);
+		}
+
+		/* transfer complete interrupt */
+		if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB) {
+			gpi_process_ieob(gpii);
+			type &= ~GPII_n_CNTXT_TYPE_IRQ_MSK_IEOB;
+		}
+
+		/* event control irq */
+		if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL) {
+			u32 ev_state;
+			u32 ev_ch_irq;
+
+			dev_dbg(gpii->gpi_dev->dev,
+				"processing EV CTRL interrupt\n");
+			offset = GPII_n_CNTXT_SRC_EV_CH_IRQ_OFFS(gpii_id);
+			ev_ch_irq = gpi_read_reg(gpii, gpii->regs + offset);
+
+			offset = GPII_n_CNTXT_SRC_EV_CH_IRQ_CLR_OFFS
+				(gpii_id);
+			gpi_write_reg(gpii, gpii->regs + offset, ev_ch_irq);
+			ev_state = gpi_read_reg(gpii, gpii->ev_cntxt_base_reg +
+						CNTXT_0_CONFIG);
+			ev_state = FIELD_GET(GPII_n_EV_k_CNTXT_0_CHSTATE, ev_state);
+
+			/*
+			 * CMD EV_CMD_DEALLOC is always successful. However
+			 * cmd does not change hardware status. So overwriting
+			 * software state to default state.
+			 */
+			if (gpii->gpi_cmd == GPI_EV_CMD_DEALLOC)
+				ev_state = DEFAULT_EV_CH_STATE;
+
+			gpii->ev_state = ev_state;
+			dev_dbg(gpii->gpi_dev->dev, "setting EV state to %s\n",
+				TO_GPI_EV_STATE_STR(gpii->ev_state));
+			complete_all(&gpii->cmd_completion);
+			type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_EV_CTRL);
+		}
+
+		/* channel control irq */
+		if (type & GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL) {
+			dev_dbg(gpii->gpi_dev->dev, "process CH CTRL interrupts\n");
+			gpi_process_ch_ctrl_irq(gpii);
+			type &= ~(GPII_n_CNTXT_TYPE_IRQ_MSK_CH_CTRL);
+		}
+
+		if (type) {
+			dev_err(gpii->gpi_dev->dev, "Unhandled interrupt status:0x%x\n", type);
+			gpi_process_gen_err_irq(gpii);
+			goto exit_irq;
+		}
+
+		offset = GPII_n_CNTXT_TYPE_IRQ_OFFS(gpii->gpii_id);
+		type = gpi_read_reg(gpii, gpii->regs + offset);
+	} while (type);
+
+exit_irq:
+	read_unlock_irqrestore(&gpii->pm_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+/* process DMA Immediate completion data events */
+static void gpi_process_imed_data_event(struct gchan *gchan,
+					struct immediate_data_event *imed_event)
+{
+	struct gpii *gpii = gchan->gpii;
+	struct gpi_ring *ch_ring = &gchan->ch_ring;
+	void *tre = ch_ring->base + (ch_ring->el_size * imed_event->tre_index);
+	struct dmaengine_result result;
+	struct gpi_desc *gpi_desc;
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+	u32 chid;
+
+	/*
+	 * If channel not active don't process event
+	 */
+	if (gchan->pm_state != ACTIVE_STATE) {
+		dev_err(gpii->gpi_dev->dev, "skipping processing event because ch @ %s state\n",
+			TO_GPI_PM_STR(gchan->pm_state));
+		return;
+	}
+
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	vd = vchan_next_desc(&gchan->vc);
+	if (!vd) {
+		struct gpi_ere *gpi_ere;
+		struct gpi_tre *gpi_tre;
+
+		spin_unlock_irqrestore(&gchan->vc.lock, flags);
+		dev_dbg(gpii->gpi_dev->dev, "event without a pending descriptor!\n");
+		gpi_ere = (struct gpi_ere *)imed_event;
+		dev_dbg(gpii->gpi_dev->dev,
+			"Event: %08x %08x %08x %08x\n",
+			gpi_ere->dword[0], gpi_ere->dword[1],
+			gpi_ere->dword[2], gpi_ere->dword[3]);
+		gpi_tre = tre;
+		dev_dbg(gpii->gpi_dev->dev,
+			"Pending TRE: %08x %08x %08x %08x\n",
+			gpi_tre->dword[0], gpi_tre->dword[1],
+			gpi_tre->dword[2], gpi_tre->dword[3]);
+		return;
+	}
+	gpi_desc = to_gpi_desc(vd);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+
+	/*
+	 * RP pointed by Event is to last TRE processed,
+	 * we need to update ring rp to tre + 1
+	 */
+	tre += ch_ring->el_size;
+	if (tre >= (ch_ring->base + ch_ring->len))
+		tre = ch_ring->base;
+	ch_ring->rp = tre;
+
+	/* make sure rp updates are immediately visible to all cores */
+	smp_wmb();
+
+	chid = imed_event->chid;
+	if (imed_event->code == MSM_GPI_TCE_EOT && gpii->ieob_set) {
+		if (chid == GPI_RX_CHAN)
+			goto gpi_free_desc;
+		else
+			return;
+	}
+
+	if (imed_event->code == MSM_GPI_TCE_UNEXP_ERR)
+		result.result = DMA_TRANS_ABORTED;
+	else
+		result.result = DMA_TRANS_NOERROR;
+	result.residue = gpi_desc->len - imed_event->length;
+
+	dma_cookie_complete(&vd->tx);
+	dmaengine_desc_get_callback_invoke(&vd->tx, &result);
+
+gpi_free_desc:
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	list_del(&vd->node);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+	kfree(gpi_desc);
+	gpi_desc = NULL;
+}
+
+/* processing transfer completion events */
+static void gpi_process_xfer_compl_event(struct gchan *gchan,
+					 struct xfer_compl_event *compl_event)
+{
+	struct gpii *gpii = gchan->gpii;
+	struct gpi_ring *ch_ring = &gchan->ch_ring;
+	void *ev_rp = to_virtual(ch_ring, compl_event->ptr);
+	struct virt_dma_desc *vd;
+	struct gpi_desc *gpi_desc;
+	struct dmaengine_result result;
+	unsigned long flags;
+	u32 chid;
+
+	/* only process events on active channel */
+	if (unlikely(gchan->pm_state != ACTIVE_STATE)) {
+		dev_err(gpii->gpi_dev->dev, "skipping processing event because ch @ %s state\n",
+			TO_GPI_PM_STR(gchan->pm_state));
+		return;
+	}
+
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	vd = vchan_next_desc(&gchan->vc);
+	if (!vd) {
+		struct gpi_ere *gpi_ere;
+
+		spin_unlock_irqrestore(&gchan->vc.lock, flags);
+		dev_err(gpii->gpi_dev->dev, "Event without a pending descriptor!\n");
+		gpi_ere = (struct gpi_ere *)compl_event;
+		dev_err(gpii->gpi_dev->dev,
+			"Event: %08x %08x %08x %08x\n",
+			gpi_ere->dword[0], gpi_ere->dword[1],
+			gpi_ere->dword[2], gpi_ere->dword[3]);
+		return;
+	}
+
+	gpi_desc = to_gpi_desc(vd);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+
+	/*
+	 * RP pointed by Event is to last TRE processed,
+	 * we need to update ring rp to ev_rp + 1
+	 */
+	ev_rp += ch_ring->el_size;
+	if (ev_rp >= (ch_ring->base + ch_ring->len))
+		ev_rp = ch_ring->base;
+	ch_ring->rp = ev_rp;
+
+	/* update must be visible to other cores */
+	smp_wmb();
+
+	chid = compl_event->chid;
+	if (compl_event->code == MSM_GPI_TCE_EOT && gpii->ieob_set) {
+		if (chid == GPI_RX_CHAN)
+			goto gpi_free_desc;
+		else
+			return;
+	}
+
+	if (compl_event->code == MSM_GPI_TCE_UNEXP_ERR) {
+		dev_err(gpii->gpi_dev->dev, "Error in Transaction\n");
+		result.result = DMA_TRANS_ABORTED;
+	} else {
+		dev_dbg(gpii->gpi_dev->dev, "Transaction Success\n");
+		result.result = DMA_TRANS_NOERROR;
+	}
+	result.residue = gpi_desc->len - compl_event->length;
+	dev_dbg(gpii->gpi_dev->dev, "Residue %d\n", result.residue);
+
+	dma_cookie_complete(&vd->tx);
+	dmaengine_desc_get_callback_invoke(&vd->tx, &result);
+
+gpi_free_desc:
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	list_del(&vd->node);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+	kfree(gpi_desc);
+	gpi_desc = NULL;
+}
+
+/* process all events */
+static void gpi_process_events(struct gpii *gpii)
+{
+	struct gpi_ring *ev_ring = &gpii->ev_ring;
+	phys_addr_t cntxt_rp;
+	void *rp;
+	union gpi_event *gpi_event;
+	struct gchan *gchan;
+	u32 chid, type;
+
+	cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
+	rp = to_virtual(ev_ring, cntxt_rp);
+
+	do {
+		while (rp != ev_ring->rp) {
+			gpi_event = ev_ring->rp;
+			chid = gpi_event->xfer_compl_event.chid;
+			type = gpi_event->xfer_compl_event.type;
+
+			dev_dbg(gpii->gpi_dev->dev,
+				"Event: CHID:%u, type:%x %08x %08x %08x %08x\n",
+				chid, type, gpi_event->gpi_ere.dword[0],
+				gpi_event->gpi_ere.dword[1], gpi_event->gpi_ere.dword[2],
+				gpi_event->gpi_ere.dword[3]);
+
+			switch (type) {
+			case XFER_COMPLETE_EV_TYPE:
+				gchan = &gpii->gchan[chid];
+				gpi_process_xfer_compl_event(gchan,
+							     &gpi_event->xfer_compl_event);
+				break;
+			case STALE_EV_TYPE:
+				dev_dbg(gpii->gpi_dev->dev, "stale event, not processing\n");
+				break;
+			case IMMEDIATE_DATA_EV_TYPE:
+				gchan = &gpii->gchan[chid];
+				gpi_process_imed_data_event(gchan,
+							    &gpi_event->immediate_data_event);
+				break;
+			case QUP_NOTIF_EV_TYPE:
+				dev_dbg(gpii->gpi_dev->dev, "QUP_NOTIF_EV_TYPE\n");
+				break;
+			default:
+				dev_dbg(gpii->gpi_dev->dev,
+					"not supported event type:0x%x\n", type);
+			}
+			gpi_ring_recycle_ev_element(ev_ring);
+		}
+		gpi_write_ev_db(gpii, ev_ring, ev_ring->wp);
+
+		/* clear pending IEOB events */
+		gpi_write_reg(gpii, gpii->ieob_clr_reg, BIT(0));
+
+		cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
+		rp = to_virtual(ev_ring, cntxt_rp);
+
+	} while (rp != ev_ring->rp);
+}
+
+/* processing events using tasklet */
+static void gpi_ev_tasklet(unsigned long data)
+{
+	struct gpii *gpii = (struct gpii *)data;
+
+	read_lock_bh(&gpii->pm_lock);
+	if (!REG_ACCESS_VALID(gpii->pm_state)) {
+		read_unlock_bh(&gpii->pm_lock);
+		dev_err(gpii->gpi_dev->dev, "not processing any events, pm_state:%s\n",
+			TO_GPI_PM_STR(gpii->pm_state));
+		return;
+	}
+
+	/* process the events */
+	gpi_process_events(gpii);
+
+	/* enable IEOB, switching back to interrupts */
+	gpi_config_interrupts(gpii, MASK_IEOB_SETTINGS, 1);
+	read_unlock_bh(&gpii->pm_lock);
+}
+
+/* marks all pending events for the channel as stale */
+static void gpi_mark_stale_events(struct gchan *gchan)
+{
+	struct gpii *gpii = gchan->gpii;
+	struct gpi_ring *ev_ring = &gpii->ev_ring;
+	u32 cntxt_rp, local_rp;
+	void *ev_rp;
+
+	cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
+
+	ev_rp = ev_ring->rp;
+	local_rp = (u32)to_physical(ev_ring, ev_rp);
+	while (local_rp != cntxt_rp) {
+		union gpi_event *gpi_event = ev_rp;
+		u32 chid = gpi_event->xfer_compl_event.chid;
+
+		if (chid == gchan->chid)
+			gpi_event->xfer_compl_event.type = STALE_EV_TYPE;
+		ev_rp += ev_ring->el_size;
+		if (ev_rp >= (ev_ring->base + ev_ring->len))
+			ev_rp = ev_ring->base;
+		cntxt_rp = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
+		local_rp = (u32)to_physical(ev_ring, ev_rp);
+	}
+}
+
+/* reset sw state and issue channel reset or de-alloc */
+static int gpi_reset_chan(struct gchan *gchan, enum gpi_cmd gpi_cmd)
+{
+	struct gpii *gpii = gchan->gpii;
+	struct gpi_ring *ch_ring = &gchan->ch_ring;
+	unsigned long flags;
+	LIST_HEAD(list);
+	int ret;
+
+	ret = gpi_send_cmd(gpii, gchan, gpi_cmd);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
+			TO_GPI_CMD_STR(gpi_cmd), ret);
+		return ret;
+	}
+
+	/* initialize the local ring ptrs */
+	ch_ring->rp = ch_ring->base;
+	ch_ring->wp = ch_ring->base;
+
+	/* visible to other cores */
+	smp_wmb();
+
+	/* check event ring for any stale events */
+	write_lock_irq(&gpii->pm_lock);
+	gpi_mark_stale_events(gchan);
+
+	/* remove all async descriptors */
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	vchan_get_all_descriptors(&gchan->vc, &list);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+	write_unlock_irq(&gpii->pm_lock);
+	vchan_dma_desc_free_list(&gchan->vc, &list);
+
+	return 0;
+}
+
+static int gpi_start_chan(struct gchan *gchan)
+{
+	struct gpii *gpii = gchan->gpii;
+	int ret;
+
+	ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_START);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
+			TO_GPI_CMD_STR(GPI_CH_CMD_START), ret);
+		return ret;
+	}
+
+	/* gpii CH is active now */
+	write_lock_irq(&gpii->pm_lock);
+	gchan->pm_state = ACTIVE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+
+	return 0;
+}
+
+static int gpi_stop_chan(struct gchan *gchan)
+{
+	struct gpii *gpii = gchan->gpii;
+	int ret;
+
+	ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_STOP);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
+			TO_GPI_CMD_STR(GPI_CH_CMD_STOP), ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* allocate and configure the transfer channel */
+static int gpi_alloc_chan(struct gchan *chan, bool send_alloc_cmd)
+{
+	struct gpii *gpii = chan->gpii;
+	struct gpi_ring *ring = &chan->ch_ring;
+	int ret;
+	u32 id = gpii->gpii_id;
+	u32 chid = chan->chid;
+	u32 pair_chid = !chid;
+
+	if (send_alloc_cmd) {
+		ret = gpi_send_cmd(gpii, chan, GPI_CH_CMD_ALLOCATE);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error with cmd:%s ret:%d\n",
+				TO_GPI_CMD_STR(GPI_CH_CMD_ALLOCATE), ret);
+			return ret;
+		}
+	}
+
+	gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_0_CONFIG,
+		      GPII_n_CH_k_CNTXT_0(ring->el_size, 0, chan->dir, GPI_CHTYPE_PROTO_GPI));
+	gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_1_R_LENGTH, ring->len);
+	gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_2_RING_BASE_LSB, ring->phys_addr);
+	gpi_write_reg(gpii, chan->ch_cntxt_base_reg + CNTXT_3_RING_BASE_MSB,
+		      upper_32_bits(ring->phys_addr));
+	gpi_write_reg(gpii, chan->ch_cntxt_db_reg + CNTXT_5_RING_RP_MSB - CNTXT_4_RING_RP_LSB,
+		      upper_32_bits(ring->phys_addr));
+	gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_0_OFFS(id, chid),
+		      GPII_n_CH_k_SCRATCH_0(pair_chid, chan->protocol, chan->seid));
+	gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_1_OFFS(id, chid), 0);
+	gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_2_OFFS(id, chid), 0);
+	gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_SCRATCH_3_OFFS(id, chid), 0);
+	gpi_write_reg(gpii, gpii->regs + GPII_n_CH_k_QOS_OFFS(id, chid), 1);
+
+	/* flush all the writes */
+	wmb();
+	return 0;
+}
+
+/* allocate and configure event ring */
+static int gpi_alloc_ev_chan(struct gpii *gpii)
+{
+	struct gpi_ring *ring = &gpii->ev_ring;
+	void __iomem *base = gpii->ev_cntxt_base_reg;
+	int ret;
+
+	ret = gpi_send_cmd(gpii, NULL, GPI_EV_CMD_ALLOCATE);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "error with cmd:%s ret:%d\n",
+			TO_GPI_CMD_STR(GPI_EV_CMD_ALLOCATE), ret);
+		return ret;
+	}
+
+	/* program event context */
+	gpi_write_reg(gpii, base + CNTXT_0_CONFIG,
+		      GPII_n_EV_k_CNTXT_0(ring->el_size, GPI_INTTYPE_IRQ, GPI_CHTYPE_GPI_EV));
+	gpi_write_reg(gpii, base + CNTXT_1_R_LENGTH, ring->len);
+	gpi_write_reg(gpii, base + CNTXT_2_RING_BASE_LSB, lower_32_bits(ring->phys_addr));
+	gpi_write_reg(gpii, base + CNTXT_3_RING_BASE_MSB, upper_32_bits(ring->phys_addr));
+	gpi_write_reg(gpii, gpii->ev_cntxt_db_reg + CNTXT_5_RING_RP_MSB - CNTXT_4_RING_RP_LSB,
+		      upper_32_bits(ring->phys_addr));
+	gpi_write_reg(gpii, base + CNTXT_8_RING_INT_MOD, 0);
+	gpi_write_reg(gpii, base + CNTXT_10_RING_MSI_LSB, 0);
+	gpi_write_reg(gpii, base + CNTXT_11_RING_MSI_MSB, 0);
+	gpi_write_reg(gpii, base + CNTXT_8_RING_INT_MOD, 0);
+	gpi_write_reg(gpii, base + CNTXT_12_RING_RP_UPDATE_LSB, 0);
+	gpi_write_reg(gpii, base + CNTXT_13_RING_RP_UPDATE_MSB, 0);
+
+	/* add events to ring */
+	ring->wp = (ring->base + ring->len - ring->el_size);
+
+	/* flush all the writes */
+	wmb();
+
+	/* gpii is active now */
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = ACTIVE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+	gpi_write_ev_db(gpii, ring, ring->wp);
+
+	return 0;
+}
+
+/* calculate # of ERE/TRE available to queue */
+static int gpi_ring_num_elements_avail(const struct gpi_ring * const ring)
+{
+	int elements = 0;
+
+	if (ring->wp < ring->rp) {
+		elements = ((ring->rp - ring->wp) / ring->el_size) - 1;
+	} else {
+		elements = (ring->rp - ring->base) / ring->el_size;
+		elements += ((ring->base + ring->len - ring->wp) / ring->el_size) - 1;
+	}
+
+	return elements;
+}
+
+static int gpi_ring_add_element(struct gpi_ring *ring, void **wp)
+{
+	if (gpi_ring_num_elements_avail(ring) <= 0)
+		return -ENOMEM;
+
+	*wp = ring->wp;
+	ring->wp += ring->el_size;
+	if (ring->wp  >= (ring->base + ring->len))
+		ring->wp = ring->base;
+
+	/* visible to other cores */
+	smp_wmb();
+
+	return 0;
+}
+
+static void gpi_ring_recycle_ev_element(struct gpi_ring *ring)
+{
+	/* Update the WP */
+	ring->wp += ring->el_size;
+	if (ring->wp  >= (ring->base + ring->len))
+		ring->wp = ring->base;
+
+	/* Update the RP */
+	ring->rp += ring->el_size;
+	if (ring->rp  >= (ring->base + ring->len))
+		ring->rp = ring->base;
+
+	/* visible to other cores */
+	smp_wmb();
+}
+
+static void gpi_free_ring(struct gpi_ring *ring,
+			  struct gpii *gpii)
+{
+	dma_free_coherent(gpii->gpi_dev->dev, ring->alloc_size,
+			  ring->pre_aligned, ring->dma_handle);
+	memset(ring, 0, sizeof(*ring));
+}
+
+/* allocate memory for transfer and event rings */
+static int gpi_alloc_ring(struct gpi_ring *ring, u32 elements,
+			  u32 el_size, struct gpii *gpii)
+{
+	u64 len = elements * el_size;
+	int bit;
+
+	/* ring len must be power of 2 */
+	bit = find_last_bit((unsigned long *)&len, 32);
+	if (((1 << bit) - 1) & len)
+		bit++;
+	len = 1 << bit;
+	ring->alloc_size = (len + (len - 1));
+	dev_dbg(gpii->gpi_dev->dev,
+		"#el:%u el_size:%u len:%u actual_len:%llu alloc_size:%lu\n",
+		  elements, el_size, (elements * el_size), len,
+		  ring->alloc_size);
+
+	ring->pre_aligned = dma_alloc_coherent(gpii->gpi_dev->dev,
+					       ring->alloc_size,
+					       &ring->dma_handle, GFP_KERNEL);
+	if (!ring->pre_aligned) {
+		dev_err(gpii->gpi_dev->dev, "could not alloc size:%lu mem for ring\n",
+			ring->alloc_size);
+		return -ENOMEM;
+	}
+
+	/* align the physical mem */
+	ring->phys_addr = (ring->dma_handle + (len - 1)) & ~(len - 1);
+	ring->base = ring->pre_aligned + (ring->phys_addr - ring->dma_handle);
+	ring->rp = ring->base;
+	ring->wp = ring->base;
+	ring->len = len;
+	ring->el_size = el_size;
+	ring->elements = ring->len / ring->el_size;
+	memset(ring->base, 0, ring->len);
+	ring->configured = true;
+
+	/* update to other cores */
+	smp_wmb();
+
+	dev_dbg(gpii->gpi_dev->dev,
+		"phy_pre:0x%0llx phy_alig:0x%0llx len:%u el_size:%u elements:%u\n",
+		ring->dma_handle, ring->phys_addr, ring->len,
+		ring->el_size, ring->elements);
+
+	return 0;
+}
+
+/* copy tre into transfer ring */
+static void gpi_queue_xfer(struct gpii *gpii, struct gchan *gchan,
+			   struct gpi_tre *gpi_tre, void **wp)
+{
+	struct gpi_tre *ch_tre;
+	int ret;
+
+	/* get next tre location we can copy */
+	ret = gpi_ring_add_element(&gchan->ch_ring, (void **)&ch_tre);
+	if (unlikely(ret)) {
+		dev_err(gpii->gpi_dev->dev, "Error adding ring element to xfer ring\n");
+		return;
+	}
+
+	/* copy the tre info */
+	memcpy(ch_tre, gpi_tre, sizeof(*ch_tre));
+	*wp = ch_tre;
+}
+
+/* reset and restart transfer channel */
+static int gpi_terminate_all(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	int schid, echid, i;
+	int ret = 0;
+
+	mutex_lock(&gpii->ctrl_lock);
+
+	/*
+	 * treat both channels as a group if its protocol is not UART
+	 * STOP, RESET, or START needs to be in lockstep
+	 */
+	schid = (gchan->protocol == QCOM_GPI_UART) ? gchan->chid : 0;
+	echid = (gchan->protocol == QCOM_GPI_UART) ? schid + 1 : MAX_CHANNELS_PER_GPII;
+
+	/* stop the channel */
+	for (i = schid; i < echid; i++) {
+		gchan = &gpii->gchan[i];
+
+		/* disable ch state so no more TRE processing */
+		write_lock_irq(&gpii->pm_lock);
+		gchan->pm_state = PREPARE_TERMINATE;
+		write_unlock_irq(&gpii->pm_lock);
+
+		/* send command to Stop the channel */
+		ret = gpi_stop_chan(gchan);
+	}
+
+	/* reset the channels (clears any pending tre) */
+	for (i = schid; i < echid; i++) {
+		gchan = &gpii->gchan[i];
+
+		ret = gpi_reset_chan(gchan, GPI_CH_CMD_RESET);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error resetting channel ret:%d\n", ret);
+			goto terminate_exit;
+		}
+
+		/* reprogram channel CNTXT */
+		ret = gpi_alloc_chan(gchan, false);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error alloc_channel ret:%d\n", ret);
+			goto terminate_exit;
+		}
+	}
+
+	/* restart the channels */
+	for (i = schid; i < echid; i++) {
+		gchan = &gpii->gchan[i];
+
+		ret = gpi_start_chan(gchan);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error Starting Channel ret:%d\n", ret);
+			goto terminate_exit;
+		}
+	}
+
+terminate_exit:
+	mutex_unlock(&gpii->ctrl_lock);
+	return ret;
+}
+
+/* pause dma transfer for all channels */
+static int gpi_pause(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	int i, ret;
+
+	mutex_lock(&gpii->ctrl_lock);
+
+	/*
+	 * pause/resume are per gpii not per channel, so
+	 * client needs to call pause only once
+	 */
+	if (gpii->pm_state == PAUSE_STATE) {
+		dev_dbg(gpii->gpi_dev->dev, "channel is already paused\n");
+		mutex_unlock(&gpii->ctrl_lock);
+		return 0;
+	}
+
+	/* send stop command to stop the channels */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
+		ret = gpi_stop_chan(&gpii->gchan[i]);
+		if (ret) {
+			mutex_unlock(&gpii->ctrl_lock);
+			return ret;
+		}
+	}
+
+	disable_irq(gpii->irq);
+
+	/* Wait for threads to complete out */
+	tasklet_kill(&gpii->ev_task);
+
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = PAUSE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+	mutex_unlock(&gpii->ctrl_lock);
+
+	return 0;
+}
+
+/* resume dma transfer */
+static int gpi_resume(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	int i, ret;
+
+	mutex_lock(&gpii->ctrl_lock);
+	if (gpii->pm_state == ACTIVE_STATE) {
+		dev_dbg(gpii->gpi_dev->dev, "channel is already active\n");
+		mutex_unlock(&gpii->ctrl_lock);
+		return 0;
+	}
+
+	enable_irq(gpii->irq);
+
+	/* send start command to start the channels */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
+		ret = gpi_send_cmd(gpii, &gpii->gchan[i], GPI_CH_CMD_START);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error starting chan, ret:%d\n", ret);
+			mutex_unlock(&gpii->ctrl_lock);
+			return ret;
+		}
+	}
+
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = ACTIVE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+	mutex_unlock(&gpii->ctrl_lock);
+
+	return 0;
+}
+
+static void gpi_desc_free(struct virt_dma_desc *vd)
+{
+	struct gpi_desc *gpi_desc = to_gpi_desc(vd);
+
+	kfree(gpi_desc);
+	gpi_desc = NULL;
+}
+
+static int
+gpi_peripheral_config(struct dma_chan *chan, struct dma_slave_config *config)
+{
+	struct gchan *gchan = to_gchan(chan);
+
+	if (!config->peripheral_config)
+		return -EINVAL;
+
+	gchan->config = krealloc(gchan->config, config->peripheral_size, GFP_NOWAIT);
+	if (!gchan->config)
+		return -ENOMEM;
+
+	memcpy(gchan->config, config->peripheral_config, config->peripheral_size);
+
+	return 0;
+}
+
+static int gpi_create_i2c_tre(struct gchan *chan, struct gpi_desc *desc,
+			      struct scatterlist *sgl, enum dma_transfer_direction direction)
+{
+	struct gpi_i2c_config *i2c = chan->config;
+	struct device *dev = chan->gpii->gpi_dev->dev;
+	unsigned int tre_idx = 0;
+	dma_addr_t address;
+	struct gpi_tre *tre;
+	unsigned int i;
+
+	/* first create config tre if applicable */
+	if (i2c->set_config) {
+		tre = &desc->tre[tre_idx];
+		tre_idx++;
+
+		tre->dword[0] = u32_encode_bits(i2c->low_count, TRE_I2C_C0_TLOW);
+		tre->dword[0] |= u32_encode_bits(i2c->high_count, TRE_I2C_C0_THIGH);
+		tre->dword[0] |= u32_encode_bits(i2c->cycle_count, TRE_I2C_C0_TCYL);
+		tre->dword[0] |= u32_encode_bits(i2c->pack_enable, TRE_I2C_C0_TX_PACK);
+		tre->dword[0] |= u32_encode_bits(i2c->pack_enable, TRE_I2C_C0_RX_PACK);
+
+		tre->dword[1] = 0;
+
+		tre->dword[2] = u32_encode_bits(i2c->clk_div, TRE_C0_CLK_DIV);
+
+		tre->dword[3] = u32_encode_bits(TRE_TYPE_CONFIG0, TRE_FLAGS_TYPE);
+		tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
+	}
+
+	/* create the GO tre for Tx */
+	if (i2c->op == I2C_WRITE) {
+		tre = &desc->tre[tre_idx];
+		tre_idx++;
+
+		if (i2c->multi_msg)
+			tre->dword[0] = u32_encode_bits(I2C_READ, TRE_I2C_GO_CMD);
+		else
+			tre->dword[0] = u32_encode_bits(i2c->op, TRE_I2C_GO_CMD);
+
+		tre->dword[0] |= u32_encode_bits(i2c->addr, TRE_I2C_GO_ADDR);
+		tre->dword[0] |= u32_encode_bits(i2c->stretch, TRE_I2C_GO_STRETCH);
+
+		tre->dword[1] = 0;
+		tre->dword[2] = u32_encode_bits(i2c->rx_len, TRE_RX_LEN);
+
+		tre->dword[3] = u32_encode_bits(TRE_TYPE_GO, TRE_FLAGS_TYPE);
+
+		if (i2c->multi_msg)
+			tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_LINK);
+		else
+			tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
+	}
+
+	if (i2c->op == I2C_READ || i2c->multi_msg == false) {
+		/* create the DMA TRE */
+		tre = &desc->tre[tre_idx];
+		tre_idx++;
+
+		address = sg_dma_address(sgl);
+		tre->dword[0] = lower_32_bits(address);
+		tre->dword[1] = upper_32_bits(address);
+
+		tre->dword[2] = u32_encode_bits(sg_dma_len(sgl), TRE_DMA_LEN);
+
+		tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE);
+		tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOT);
+	};
+
+	for (i = 0; i < tre_idx; i++)
+		dev_dbg(dev, "TRE:%d %x:%x:%x:%x\n", i, desc->tre[i].dword[0],
+			desc->tre[i].dword[1], desc->tre[i].dword[2], desc->tre[i].dword[3]);
+
+	return tre_idx;
+}
+
+static int gpi_create_spi_tre(struct gchan *chan, struct gpi_desc *desc,
+			      struct scatterlist *sgl, enum dma_transfer_direction direction)
+{
+	struct gpi_spi_config *spi = chan->config;
+	struct device *dev = chan->gpii->gpi_dev->dev;
+	unsigned int tre_idx = 0;
+	dma_addr_t address;
+	struct gpi_tre *tre;
+	unsigned int i;
+
+	/* first create config tre if applicable */
+	if (direction == DMA_MEM_TO_DEV && spi->set_config) {
+		tre = &desc->tre[tre_idx];
+		tre_idx++;
+
+		tre->dword[0] = u32_encode_bits(spi->word_len, TRE_SPI_C0_WORD_SZ);
+		tre->dword[0] |= u32_encode_bits(spi->loopback_en, TRE_SPI_C0_LOOPBACK);
+		tre->dword[0] |= u32_encode_bits(spi->clock_pol_high, TRE_SPI_C0_CPOL);
+		tre->dword[0] |= u32_encode_bits(spi->data_pol_high, TRE_SPI_C0_CPHA);
+		tre->dword[0] |= u32_encode_bits(spi->pack_en, TRE_SPI_C0_TX_PACK);
+		tre->dword[0] |= u32_encode_bits(spi->pack_en, TRE_SPI_C0_RX_PACK);
+
+		tre->dword[1] = 0;
+
+		tre->dword[2] = u32_encode_bits(spi->clk_div, TRE_C0_CLK_DIV);
+		tre->dword[2] |= u32_encode_bits(spi->clk_src, TRE_C0_CLK_SRC);
+
+		tre->dword[3] = u32_encode_bits(TRE_TYPE_CONFIG0, TRE_FLAGS_TYPE);
+		tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
+	}
+
+	/* create the GO tre for Tx */
+	if (direction == DMA_MEM_TO_DEV) {
+		tre = &desc->tre[tre_idx];
+		tre_idx++;
+
+		tre->dword[0] = u32_encode_bits(spi->fragmentation, TRE_SPI_GO_FRAG);
+		tre->dword[0] |= u32_encode_bits(spi->cs, TRE_SPI_GO_CS);
+		tre->dword[0] |= u32_encode_bits(spi->cmd, TRE_SPI_GO_CMD);
+
+		tre->dword[1] = 0;
+
+		tre->dword[2] = u32_encode_bits(spi->rx_len, TRE_RX_LEN);
+
+		tre->dword[3] = u32_encode_bits(TRE_TYPE_GO, TRE_FLAGS_TYPE);
+		if (spi->cmd == SPI_RX)
+			tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOB);
+		else
+			tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_CHAIN);
+	}
+
+	/* create the dma tre */
+	tre = &desc->tre[tre_idx];
+	tre_idx++;
+
+	address = sg_dma_address(sgl);
+	tre->dword[0] = lower_32_bits(address);
+	tre->dword[1] = upper_32_bits(address);
+
+	tre->dword[2] = u32_encode_bits(sg_dma_len(sgl), TRE_DMA_LEN);
+
+	tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE);
+	if (direction == DMA_MEM_TO_DEV)
+		tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOT);
+
+	for (i = 0; i < tre_idx; i++)
+		dev_dbg(dev, "TRE:%d %x:%x:%x:%x\n", i, desc->tre[i].dword[0],
+			desc->tre[i].dword[1], desc->tre[i].dword[2], desc->tre[i].dword[3]);
+
+	return tre_idx;
+}
+
+/* copy tre into transfer ring */
+static struct dma_async_tx_descriptor *
+gpi_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		  unsigned int sg_len, enum dma_transfer_direction direction,
+		  unsigned long flags, void *context)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	struct device *dev = gpii->gpi_dev->dev;
+	struct gpi_ring *ch_ring = &gchan->ch_ring;
+	struct gpi_desc *gpi_desc;
+	u32 nr, nr_tre = 0;
+	u8 set_config;
+	int i;
+
+	gpii->ieob_set = false;
+	if (!is_slave_direction(direction)) {
+		dev_err(gpii->gpi_dev->dev, "invalid dma direction: %d\n", direction);
+		return NULL;
+	}
+
+	if (sg_len > 1) {
+		dev_err(dev, "Multi sg sent, we support only one atm: %d\n", sg_len);
+		return NULL;
+	}
+
+	nr_tre = 3;
+	set_config = *(u32 *)gchan->config;
+	if (!set_config)
+		nr_tre = 2;
+	if (direction == DMA_DEV_TO_MEM) /* rx */
+		nr_tre = 1;
+
+	/* calculate # of elements required & available */
+	nr = gpi_ring_num_elements_avail(ch_ring);
+	if (nr < nr_tre) {
+		dev_err(dev, "not enough space in ring, avail:%u required:%u\n", nr, nr_tre);
+		return NULL;
+	}
+
+	gpi_desc = kzalloc(sizeof(*gpi_desc), GFP_NOWAIT);
+	if (!gpi_desc)
+		return NULL;
+
+	/* create TREs for xfer */
+	if (gchan->protocol == QCOM_GPI_SPI) {
+		i = gpi_create_spi_tre(gchan, gpi_desc, sgl, direction);
+	} else if (gchan->protocol == QCOM_GPI_I2C) {
+		i = gpi_create_i2c_tre(gchan, gpi_desc, sgl, direction);
+	} else {
+		dev_err(dev, "invalid peripheral: %d\n", gchan->protocol);
+		kfree(gpi_desc);
+		return NULL;
+	}
+
+	/* set up the descriptor */
+	gpi_desc->gchan = gchan;
+	gpi_desc->len = sg_dma_len(sgl);
+	gpi_desc->num_tre  = i;
+
+	return vchan_tx_prep(&gchan->vc, &gpi_desc->vd, flags);
+}
+
+/* rings transfer ring db to being transfer */
+static void gpi_issue_pending(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	unsigned long flags, pm_lock_flags;
+	struct virt_dma_desc *vd = NULL;
+	struct gpi_desc *gpi_desc;
+	struct gpi_ring *ch_ring = &gchan->ch_ring;
+	void *tre, *wp = NULL;
+	int i;
+
+	read_lock_irqsave(&gpii->pm_lock, pm_lock_flags);
+
+	/* move all submitted discriptors to issued list */
+	spin_lock_irqsave(&gchan->vc.lock, flags);
+	if (vchan_issue_pending(&gchan->vc))
+		vd = list_last_entry(&gchan->vc.desc_issued,
+				     struct virt_dma_desc, node);
+	spin_unlock_irqrestore(&gchan->vc.lock, flags);
+
+	/* nothing to do list is empty */
+	if (!vd) {
+		read_unlock_irqrestore(&gpii->pm_lock, pm_lock_flags);
+		return;
+	}
+
+	gpi_desc = to_gpi_desc(vd);
+	for (i = 0; i < gpi_desc->num_tre; i++) {
+		tre = &gpi_desc->tre[i];
+		gpi_queue_xfer(gpii, gchan, tre, &wp);
+	}
+
+	gpi_desc->db = ch_ring->wp;
+	gpi_write_ch_db(gchan, &gchan->ch_ring, gpi_desc->db);
+	read_unlock_irqrestore(&gpii->pm_lock, pm_lock_flags);
+}
+
+static int gpi_ch_init(struct gchan *gchan)
+{
+	struct gpii *gpii = gchan->gpii;
+	const int ev_factor = gpii->gpi_dev->ev_factor;
+	u32 elements;
+	int i = 0, ret = 0;
+
+	gchan->pm_state = CONFIG_STATE;
+
+	/* check if both channels are configured before continue */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++)
+		if (gpii->gchan[i].pm_state != CONFIG_STATE)
+			goto exit_gpi_init;
+
+	/* protocol must be same for both channels */
+	if (gpii->gchan[0].protocol != gpii->gchan[1].protocol) {
+		dev_err(gpii->gpi_dev->dev, "protocol did not match protocol %u != %u\n",
+			gpii->gchan[0].protocol, gpii->gchan[1].protocol);
+		ret = -EINVAL;
+		goto exit_gpi_init;
+	}
+
+	/* allocate memory for event ring */
+	elements = CHAN_TRES << ev_factor;
+	ret = gpi_alloc_ring(&gpii->ev_ring, elements,
+			     sizeof(union gpi_event), gpii);
+	if (ret)
+		goto exit_gpi_init;
+
+	/* configure interrupts */
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = PREPARE_HARDWARE;
+	write_unlock_irq(&gpii->pm_lock);
+	ret = gpi_config_interrupts(gpii, DEFAULT_IRQ_SETTINGS, 0);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "error config. interrupts, ret:%d\n", ret);
+		goto error_config_int;
+	}
+
+	/* allocate event rings */
+	ret = gpi_alloc_ev_chan(gpii);
+	if (ret) {
+		dev_err(gpii->gpi_dev->dev, "error alloc_ev_chan:%d\n", ret);
+		goto error_alloc_ev_ring;
+	}
+
+	/* Allocate all channels */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
+		ret = gpi_alloc_chan(&gpii->gchan[i], true);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error allocating chan:%d\n", ret);
+			goto error_alloc_chan;
+		}
+	}
+
+	/* start channels  */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++) {
+		ret = gpi_start_chan(&gpii->gchan[i]);
+		if (ret) {
+			dev_err(gpii->gpi_dev->dev, "Error start chan:%d\n", ret);
+			goto error_start_chan;
+		}
+	}
+	return ret;
+
+error_start_chan:
+	for (i = i - 1; i >= 0; i++) {
+		gpi_stop_chan(&gpii->gchan[i]);
+		gpi_send_cmd(gpii, gchan, GPI_CH_CMD_RESET);
+	}
+	i = 2;
+error_alloc_chan:
+	for (i = i - 1; i >= 0; i--)
+		gpi_reset_chan(gchan, GPI_CH_CMD_DE_ALLOC);
+error_alloc_ev_ring:
+	gpi_disable_interrupts(gpii);
+error_config_int:
+	gpi_free_ring(&gpii->ev_ring, gpii);
+exit_gpi_init:
+	mutex_unlock(&gpii->ctrl_lock);
+	return ret;
+}
+
+/* release all channel resources */
+static void gpi_free_chan_resources(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	enum gpi_pm_state cur_state;
+	int ret, i;
+
+	mutex_lock(&gpii->ctrl_lock);
+
+	cur_state = gchan->pm_state;
+
+	/* disable ch state so no more TRE processing for this channel */
+	write_lock_irq(&gpii->pm_lock);
+	gchan->pm_state = PREPARE_TERMINATE;
+	write_unlock_irq(&gpii->pm_lock);
+
+	/* attempt to do graceful hardware shutdown */
+	if (cur_state == ACTIVE_STATE) {
+		gpi_stop_chan(gchan);
+
+		ret = gpi_send_cmd(gpii, gchan, GPI_CH_CMD_RESET);
+		if (ret)
+			dev_err(gpii->gpi_dev->dev, "error resetting channel:%d\n", ret);
+
+		gpi_reset_chan(gchan, GPI_CH_CMD_DE_ALLOC);
+	}
+
+	/* free all allocated memory */
+	gpi_free_ring(&gchan->ch_ring, gpii);
+	vchan_free_chan_resources(&gchan->vc);
+	kfree(gchan->config);
+
+	write_lock_irq(&gpii->pm_lock);
+	gchan->pm_state = DISABLE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+
+	/* if other rings are still active exit */
+	for (i = 0; i < MAX_CHANNELS_PER_GPII; i++)
+		if (gpii->gchan[i].ch_ring.configured)
+			goto exit_free;
+
+	/* deallocate EV Ring */
+	cur_state = gpii->pm_state;
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = PREPARE_TERMINATE;
+	write_unlock_irq(&gpii->pm_lock);
+
+	/* wait for threads to complete out */
+	tasklet_kill(&gpii->ev_task);
+
+	/* send command to de allocate event ring */
+	if (cur_state == ACTIVE_STATE)
+		gpi_send_cmd(gpii, NULL, GPI_EV_CMD_DEALLOC);
+
+	gpi_free_ring(&gpii->ev_ring, gpii);
+
+	/* disable interrupts */
+	if (cur_state == ACTIVE_STATE)
+		gpi_disable_interrupts(gpii);
+
+	/* set final state to disable */
+	write_lock_irq(&gpii->pm_lock);
+	gpii->pm_state = DISABLE_STATE;
+	write_unlock_irq(&gpii->pm_lock);
+
+exit_free:
+	mutex_unlock(&gpii->ctrl_lock);
+}
+
+/* allocate channel resources */
+static int gpi_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct gchan *gchan = to_gchan(chan);
+	struct gpii *gpii = gchan->gpii;
+	int ret;
+
+	mutex_lock(&gpii->ctrl_lock);
+
+	/* allocate memory for transfer ring */
+	ret = gpi_alloc_ring(&gchan->ch_ring, CHAN_TRES,
+			     sizeof(struct gpi_tre), gpii);
+	if (ret)
+		goto xfer_alloc_err;
+
+	ret = gpi_ch_init(gchan);
+
+	mutex_unlock(&gpii->ctrl_lock);
+
+	return ret;
+xfer_alloc_err:
+	mutex_unlock(&gpii->ctrl_lock);
+
+	return ret;
+}
+
+static int gpi_find_avail_gpii(struct gpi_dev *gpi_dev, u32 seid)
+{
+	struct gchan *tx_chan, *rx_chan;
+	unsigned int gpii;
+
+	/* check if same seid is already configured for another chid */
+	for (gpii = 0; gpii < gpi_dev->max_gpii; gpii++) {
+		if (!((1 << gpii) & gpi_dev->gpii_mask))
+			continue;
+
+		tx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_TX_CHAN];
+		rx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_RX_CHAN];
+
+		if (rx_chan->vc.chan.client_count && rx_chan->seid == seid)
+			return gpii;
+		if (tx_chan->vc.chan.client_count && tx_chan->seid == seid)
+			return gpii;
+	}
+
+	/* no channels configured with same seid, return next avail gpii */
+	for (gpii = 0; gpii < gpi_dev->max_gpii; gpii++) {
+		if (!((1 << gpii) & gpi_dev->gpii_mask))
+			continue;
+
+		tx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_TX_CHAN];
+		rx_chan = &gpi_dev->gpiis[gpii].gchan[GPI_RX_CHAN];
+
+		/* check if gpii is configured */
+		if (tx_chan->vc.chan.client_count ||
+		    rx_chan->vc.chan.client_count)
+			continue;
+
+		/* found a free gpii */
+		return gpii;
+	}
+
+	/* no gpii instance available to use */
+	return -EIO;
+}
+
+/* gpi_of_dma_xlate: open client requested channel */
+static struct dma_chan *gpi_of_dma_xlate(struct of_phandle_args *args,
+					 struct of_dma *of_dma)
+{
+	struct gpi_dev *gpi_dev = (struct gpi_dev *)of_dma->of_dma_data;
+	u32 seid, chid;
+	int gpii;
+	struct gchan *gchan;
+
+	if (args->args_count < 3) {
+		dev_err(gpi_dev->dev, "gpii require minimum 2 args, client passed:%d args\n",
+			args->args_count);
+		return NULL;
+	}
+
+	chid = args->args[0];
+	if (chid >= MAX_CHANNELS_PER_GPII) {
+		dev_err(gpi_dev->dev, "gpii channel:%d not valid\n", chid);
+		return NULL;
+	}
+
+	seid = args->args[1];
+
+	/* find next available gpii to use */
+	gpii = gpi_find_avail_gpii(gpi_dev, seid);
+	if (gpii < 0) {
+		dev_err(gpi_dev->dev, "no available gpii instances\n");
+		return NULL;
+	}
+
+	gchan = &gpi_dev->gpiis[gpii].gchan[chid];
+	if (gchan->vc.chan.client_count) {
+		dev_err(gpi_dev->dev, "gpii:%d chid:%d seid:%d already configured\n",
+			gpii, chid, gchan->seid);
+		return NULL;
+	}
+
+	gchan->seid = seid;
+	gchan->protocol = args->args[2];
+
+	return dma_get_slave_channel(&gchan->vc.chan);
+}
+
+static int gpi_probe(struct platform_device *pdev)
+{
+	struct gpi_dev *gpi_dev;
+	unsigned int i;
+	int ret;
+
+	gpi_dev = devm_kzalloc(&pdev->dev, sizeof(*gpi_dev), GFP_KERNEL);
+	if (!gpi_dev)
+		return -ENOMEM;
+
+	gpi_dev->dev = &pdev->dev;
+	gpi_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	gpi_dev->regs = devm_ioremap_resource(gpi_dev->dev, gpi_dev->res);
+	if (IS_ERR(gpi_dev->regs))
+		return PTR_ERR(gpi_dev->regs);
+	gpi_dev->ee_base = gpi_dev->regs;
+
+	ret = of_property_read_u32(gpi_dev->dev->of_node, "dma-channels",
+				   &gpi_dev->max_gpii);
+	if (ret) {
+		dev_err(gpi_dev->dev, "missing 'max-no-gpii' DT node\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(gpi_dev->dev->of_node, "dma-channel-mask",
+				   &gpi_dev->gpii_mask);
+	if (ret) {
+		dev_err(gpi_dev->dev, "missing 'gpii-mask' DT node\n");
+		return ret;
+	}
+
+	gpi_dev->ev_factor = EV_FACTOR;
+
+	ret = dma_set_mask(gpi_dev->dev, DMA_BIT_MASK(64));
+	if (ret) {
+		dev_err(gpi_dev->dev, "Error setting dma_mask to 64, ret:%d\n", ret);
+		return ret;
+	}
+
+	gpi_dev->gpiis = devm_kzalloc(gpi_dev->dev, sizeof(*gpi_dev->gpiis) *
+				      gpi_dev->max_gpii, GFP_KERNEL);
+	if (!gpi_dev->gpiis)
+		return -ENOMEM;
+
+	/* setup all the supported gpii */
+	INIT_LIST_HEAD(&gpi_dev->dma_device.channels);
+	for (i = 0; i < gpi_dev->max_gpii; i++) {
+		struct gpii *gpii = &gpi_dev->gpiis[i];
+		int chan;
+
+		if (!((1 << i) & gpi_dev->gpii_mask))
+			continue;
+
+		/* set up ev cntxt register map */
+		gpii->ev_cntxt_base_reg = gpi_dev->ee_base + GPII_n_EV_CH_k_CNTXT_0_OFFS(i, 0);
+		gpii->ev_cntxt_db_reg = gpi_dev->ee_base + GPII_n_EV_CH_k_DOORBELL_0_OFFS(i, 0);
+		gpii->ev_ring_rp_lsb_reg = gpii->ev_cntxt_base_reg + CNTXT_4_RING_RP_LSB;
+		gpii->ev_cmd_reg = gpi_dev->ee_base + GPII_n_EV_CH_CMD_OFFS(i);
+		gpii->ieob_clr_reg = gpi_dev->ee_base + GPII_n_CNTXT_SRC_IEOB_IRQ_CLR_OFFS(i);
+
+		/* set up irq */
+		ret = platform_get_irq(pdev, i);
+		if (ret < 0) {
+			dev_err(gpi_dev->dev, "platform_get_irq failed for %d:%d\n", i, ret);
+			return ret;
+		}
+		gpii->irq = ret;
+
+		/* set up channel specific register info */
+		for (chan = 0; chan < MAX_CHANNELS_PER_GPII; chan++) {
+			struct gchan *gchan = &gpii->gchan[chan];
+
+			/* set up ch cntxt register map */
+			gchan->ch_cntxt_base_reg = gpi_dev->ee_base +
+				GPII_n_CH_k_CNTXT_0_OFFS(i, chan);
+			gchan->ch_cntxt_db_reg = gpi_dev->ee_base +
+				GPII_n_CH_k_DOORBELL_0_OFFS(i, chan);
+			gchan->ch_cmd_reg = gpi_dev->ee_base + GPII_n_CH_CMD_OFFS(i);
+
+			/* vchan setup */
+			vchan_init(&gchan->vc, &gpi_dev->dma_device);
+			gchan->vc.desc_free = gpi_desc_free;
+			gchan->chid = chan;
+			gchan->gpii = gpii;
+			gchan->dir = GPII_CHAN_DIR[chan];
+		}
+		mutex_init(&gpii->ctrl_lock);
+		rwlock_init(&gpii->pm_lock);
+		tasklet_init(&gpii->ev_task, gpi_ev_tasklet,
+			     (unsigned long)gpii);
+		init_completion(&gpii->cmd_completion);
+		gpii->gpii_id = i;
+		gpii->regs = gpi_dev->ee_base;
+		gpii->gpi_dev = gpi_dev;
+	}
+
+	platform_set_drvdata(pdev, gpi_dev);
+
+	/* clear and Set capabilities */
+	dma_cap_zero(gpi_dev->dma_device.cap_mask);
+	dma_cap_set(DMA_SLAVE, gpi_dev->dma_device.cap_mask);
+
+	/* configure dmaengine apis */
+	gpi_dev->dma_device.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	gpi_dev->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+	gpi_dev->dma_device.src_addr_widths = DMA_SLAVE_BUSWIDTH_8_BYTES;
+	gpi_dev->dma_device.dst_addr_widths = DMA_SLAVE_BUSWIDTH_8_BYTES;
+	gpi_dev->dma_device.device_alloc_chan_resources = gpi_alloc_chan_resources;
+	gpi_dev->dma_device.device_free_chan_resources = gpi_free_chan_resources;
+	gpi_dev->dma_device.device_tx_status = dma_cookie_status;
+	gpi_dev->dma_device.device_issue_pending = gpi_issue_pending;
+	gpi_dev->dma_device.device_prep_slave_sg = gpi_prep_slave_sg;
+	gpi_dev->dma_device.device_config = gpi_peripheral_config;
+	gpi_dev->dma_device.device_terminate_all = gpi_terminate_all;
+	gpi_dev->dma_device.dev = gpi_dev->dev;
+	gpi_dev->dma_device.device_pause = gpi_pause;
+	gpi_dev->dma_device.device_resume = gpi_resume;
+
+	/* register with dmaengine framework */
+	ret = dma_async_device_register(&gpi_dev->dma_device);
+	if (ret) {
+		dev_err(gpi_dev->dev, "async_device_register failed ret:%d", ret);
+		return ret;
+	}
+
+	ret = of_dma_controller_register(gpi_dev->dev->of_node,
+					 gpi_of_dma_xlate, gpi_dev);
+	if (ret) {
+		dev_err(gpi_dev->dev, "of_dma_controller_reg failed ret:%d", ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id gpi_of_match[] = {
+	{ .compatible = "qcom,sdm845-gpi-dma" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, gpi_of_match);
+
+static struct platform_driver gpi_driver = {
+	.probe = gpi_probe,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = gpi_of_match,
+	},
+};
+
+static int __init gpi_init(void)
+{
+	return platform_driver_register(&gpi_driver);
+}
+subsys_initcall(gpi_init)
+
+MODULE_DESCRIPTION("QCOM GPI DMA engine driver");
+MODULE_LICENSE("GPL v2");