Merge branch 'topic/bam' into for-linus

Conflicts:
	drivers/dma/Makefile

Signed-off-by: Vinod Koul <vinod.koul@intel.com>

4 files changed, 1162 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
new file mode 100644
index 000000000000..d75a9d767022
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
@@ -0,0 +1,41 @@
+QCOM BAM DMA controller
+
+Required properties:
+- compatible: must contain "qcom,bam-v1.4.0" for MSM8974
+- reg: Address range for DMA registers
+- interrupts: Should contain the one interrupt shared by all channels
+- #dma-cells: must be <1>, the cell in the dmas property of the client device
+  represents the channel number
+- clocks: required clock
+- clock-names: must contain "bam_clk" entry
+- qcom,ee : indicates the active Execution Environment identifier (0-7) used in
+  the secure world.
+
+Example:
+
+	uart-bam: dma@f9984000 = {
+		compatible = "qcom,bam-v1.4.0";
+		reg = <0xf9984000 0x15000>;
+		interrupts = <0 94 0>;
+		clocks = <&gcc GCC_BAM_DMA_AHB_CLK>;
+		clock-names = "bam_clk";
+		#dma-cells = <1>;
+		qcom,ee = <0>;
+	};
+
+DMA clients must use the format described in the dma.txt file, using a two cell
+specifier for each channel.
+
+Example:
+	serial@f991e000 {
+		compatible = "qcom,msm-uart";
+		reg = <0xf991e000 0x1000>
+			<0xf9944000 0x19000>;
+		interrupts = <0 108 0>;
+		clocks = <&gcc GCC_BLSP1_UART2_APPS_CLK>,
+			<&gcc GCC_BLSP1_AHB_CLK>;
+		clock-names = "core", "iface";
+
+		dmas = <&uart-bam 0>, <&uart-bam 1>;
+		dma-names = "rx", "tx";
+	};
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 830b88d8744c..edc739f986a8 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -410,4 +410,13 @@ config DMATEST
 config DMA_ENGINE_RAID
 	bool
 
+config QCOM_BAM_DMA
+	tristate "QCOM BAM DMA support"
+	depends on ARCH_QCOM || (COMPILE_TEST && OF && ARM)
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	---help---
+	  Enable support for the QCOM BAM DMA controller.  This controller
+	  provides DMA capabilities for a variety of on-chip devices.
+
 endif
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 995946283f8d..5150c82c9caf 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -45,3 +45,4 @@ obj-$(CONFIG_TI_CPPI41) += cppi41.o
 obj-$(CONFIG_K3_DMA) += k3dma.o
 obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
 obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
+obj-$(CONFIG_QCOM_BAM_DMA) += qcom_bam_dma.o
diff --git a/drivers/dma/qcom_bam_dma.c b/drivers/dma/qcom_bam_dma.c
new file mode 100644
index 000000000000..82c923146e49
--- /dev/null
+++ b/drivers/dma/qcom_bam_dma.c
@@ -0,0 +1,1111 @@
+/*
+ * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+/*
+ * QCOM BAM DMA engine driver
+ *
+ * QCOM BAM DMA blocks are distributed amongst a number of the on-chip
+ * peripherals on the MSM 8x74.  The configuration of the channels are dependent
+ * on the way they are hard wired to that specific peripheral.  The peripheral
+ * device tree entries specify the configuration of each channel.
+ *
+ * The DMA controller requires the use of external memory for storage of the
+ * hardware descriptors for each channel.  The descriptor FIFO is accessed as a
+ * circular buffer and operations are managed according to the offset within the
+ * FIFO.  After pipe/channel reset, all of the pipe registers and internal state
+ * are back to defaults.
+ *
+ * During DMA operations, we write descriptors to the FIFO, being careful to
+ * handle wrapping and then write the last FIFO offset to that channel's
+ * P_EVNT_REG register to kick off the transaction.  The P_SW_OFSTS register
+ * indicates the current FIFO offset that is being processed, so there is some
+ * indication of where the hardware is currently working.
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_dma.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+struct bam_desc_hw {
+	u32 addr;		/* Buffer physical address */
+	u16 size;		/* Buffer size in bytes */
+	u16 flags;
+};
+
+#define DESC_FLAG_INT BIT(15)
+#define DESC_FLAG_EOT BIT(14)
+#define DESC_FLAG_EOB BIT(13)
+
+struct bam_async_desc {
+	struct virt_dma_desc vd;
+
+	u32 num_desc;
+	u32 xfer_len;
+	struct bam_desc_hw *curr_desc;
+
+	enum dma_transfer_direction dir;
+	size_t length;
+	struct bam_desc_hw desc[0];
+};
+
+#define BAM_CTRL			0x0000
+#define BAM_REVISION			0x0004
+#define BAM_SW_REVISION			0x0080
+#define BAM_NUM_PIPES			0x003C
+#define BAM_TIMER			0x0040
+#define BAM_TIMER_CTRL			0x0044
+#define BAM_DESC_CNT_TRSHLD		0x0008
+#define BAM_IRQ_SRCS			0x000C
+#define BAM_IRQ_SRCS_MSK		0x0010
+#define BAM_IRQ_SRCS_UNMASKED		0x0030
+#define BAM_IRQ_STTS			0x0014
+#define BAM_IRQ_CLR			0x0018
+#define BAM_IRQ_EN			0x001C
+#define BAM_CNFG_BITS			0x007C
+#define BAM_IRQ_SRCS_EE(ee)		(0x0800 + ((ee) * 0x80))
+#define BAM_IRQ_SRCS_MSK_EE(ee)		(0x0804 + ((ee) * 0x80))
+#define BAM_P_CTRL(pipe)		(0x1000 + ((pipe) * 0x1000))
+#define BAM_P_RST(pipe)			(0x1004 + ((pipe) * 0x1000))
+#define BAM_P_HALT(pipe)		(0x1008 + ((pipe) * 0x1000))
+#define BAM_P_IRQ_STTS(pipe)		(0x1010 + ((pipe) * 0x1000))
+#define BAM_P_IRQ_CLR(pipe)		(0x1014 + ((pipe) * 0x1000))
+#define BAM_P_IRQ_EN(pipe)		(0x1018 + ((pipe) * 0x1000))
+#define BAM_P_EVNT_DEST_ADDR(pipe)	(0x182C + ((pipe) * 0x1000))
+#define BAM_P_EVNT_REG(pipe)		(0x1818 + ((pipe) * 0x1000))
+#define BAM_P_SW_OFSTS(pipe)		(0x1800 + ((pipe) * 0x1000))
+#define BAM_P_DATA_FIFO_ADDR(pipe)	(0x1824 + ((pipe) * 0x1000))
+#define BAM_P_DESC_FIFO_ADDR(pipe)	(0x181C + ((pipe) * 0x1000))
+#define BAM_P_EVNT_TRSHLD(pipe)		(0x1828 + ((pipe) * 0x1000))
+#define BAM_P_FIFO_SIZES(pipe)		(0x1820 + ((pipe) * 0x1000))
+
+/* BAM CTRL */
+#define BAM_SW_RST			BIT(0)
+#define BAM_EN				BIT(1)
+#define BAM_EN_ACCUM			BIT(4)
+#define BAM_TESTBUS_SEL_SHIFT		5
+#define BAM_TESTBUS_SEL_MASK		0x3F
+#define BAM_DESC_CACHE_SEL_SHIFT	13
+#define BAM_DESC_CACHE_SEL_MASK		0x3
+#define BAM_CACHED_DESC_STORE		BIT(15)
+#define IBC_DISABLE			BIT(16)
+
+/* BAM REVISION */
+#define REVISION_SHIFT		0
+#define REVISION_MASK		0xFF
+#define NUM_EES_SHIFT		8
+#define NUM_EES_MASK		0xF
+#define CE_BUFFER_SIZE		BIT(13)
+#define AXI_ACTIVE		BIT(14)
+#define USE_VMIDMT		BIT(15)
+#define SECURED			BIT(16)
+#define BAM_HAS_NO_BYPASS	BIT(17)
+#define HIGH_FREQUENCY_BAM	BIT(18)
+#define INACTIV_TMRS_EXST	BIT(19)
+#define NUM_INACTIV_TMRS	BIT(20)
+#define DESC_CACHE_DEPTH_SHIFT	21
+#define DESC_CACHE_DEPTH_1	(0 << DESC_CACHE_DEPTH_SHIFT)
+#define DESC_CACHE_DEPTH_2	(1 << DESC_CACHE_DEPTH_SHIFT)
+#define DESC_CACHE_DEPTH_3	(2 << DESC_CACHE_DEPTH_SHIFT)
+#define DESC_CACHE_DEPTH_4	(3 << DESC_CACHE_DEPTH_SHIFT)
+#define CMD_DESC_EN		BIT(23)
+#define INACTIV_TMR_BASE_SHIFT	24
+#define INACTIV_TMR_BASE_MASK	0xFF
+
+/* BAM NUM PIPES */
+#define BAM_NUM_PIPES_SHIFT		0
+#define BAM_NUM_PIPES_MASK		0xFF
+#define PERIPH_NON_PIPE_GRP_SHIFT	16
+#define PERIPH_NON_PIP_GRP_MASK		0xFF
+#define BAM_NON_PIPE_GRP_SHIFT		24
+#define BAM_NON_PIPE_GRP_MASK		0xFF
+
+/* BAM CNFG BITS */
+#define BAM_PIPE_CNFG		BIT(2)
+#define BAM_FULL_PIPE		BIT(11)
+#define BAM_NO_EXT_P_RST	BIT(12)
+#define BAM_IBC_DISABLE		BIT(13)
+#define BAM_SB_CLK_REQ		BIT(14)
+#define BAM_PSM_CSW_REQ		BIT(15)
+#define BAM_PSM_P_RES		BIT(16)
+#define BAM_AU_P_RES		BIT(17)
+#define BAM_SI_P_RES		BIT(18)
+#define BAM_WB_P_RES		BIT(19)
+#define BAM_WB_BLK_CSW		BIT(20)
+#define BAM_WB_CSW_ACK_IDL	BIT(21)
+#define BAM_WB_RETR_SVPNT	BIT(22)
+#define BAM_WB_DSC_AVL_P_RST	BIT(23)
+#define BAM_REG_P_EN		BIT(24)
+#define BAM_PSM_P_HD_DATA	BIT(25)
+#define BAM_AU_ACCUMED		BIT(26)
+#define BAM_CMD_ENABLE		BIT(27)
+
+#define BAM_CNFG_BITS_DEFAULT	(BAM_PIPE_CNFG |	\
+				 BAM_NO_EXT_P_RST |	\
+				 BAM_IBC_DISABLE |	\
+				 BAM_SB_CLK_REQ |	\
+				 BAM_PSM_CSW_REQ |	\
+				 BAM_PSM_P_RES |	\
+				 BAM_AU_P_RES |		\
+				 BAM_SI_P_RES |		\
+				 BAM_WB_P_RES |		\
+				 BAM_WB_BLK_CSW |	\
+				 BAM_WB_CSW_ACK_IDL |	\
+				 BAM_WB_RETR_SVPNT |	\
+				 BAM_WB_DSC_AVL_P_RST |	\
+				 BAM_REG_P_EN |		\
+				 BAM_PSM_P_HD_DATA |	\
+				 BAM_AU_ACCUMED |	\
+				 BAM_CMD_ENABLE)
+
+/* PIPE CTRL */
+#define P_EN			BIT(1)
+#define P_DIRECTION		BIT(3)
+#define P_SYS_STRM		BIT(4)
+#define P_SYS_MODE		BIT(5)
+#define P_AUTO_EOB		BIT(6)
+#define P_AUTO_EOB_SEL_SHIFT	7
+#define P_AUTO_EOB_SEL_512	(0 << P_AUTO_EOB_SEL_SHIFT)
+#define P_AUTO_EOB_SEL_256	(1 << P_AUTO_EOB_SEL_SHIFT)
+#define P_AUTO_EOB_SEL_128	(2 << P_AUTO_EOB_SEL_SHIFT)
+#define P_AUTO_EOB_SEL_64	(3 << P_AUTO_EOB_SEL_SHIFT)
+#define P_PREFETCH_LIMIT_SHIFT	9
+#define P_PREFETCH_LIMIT_32	(0 << P_PREFETCH_LIMIT_SHIFT)
+#define P_PREFETCH_LIMIT_16	(1 << P_PREFETCH_LIMIT_SHIFT)
+#define P_PREFETCH_LIMIT_4	(2 << P_PREFETCH_LIMIT_SHIFT)
+#define P_WRITE_NWD		BIT(11)
+#define P_LOCK_GROUP_SHIFT	16
+#define P_LOCK_GROUP_MASK	0x1F
+
+/* BAM_DESC_CNT_TRSHLD */
+#define CNT_TRSHLD		0xffff
+#define DEFAULT_CNT_THRSHLD	0x4
+
+/* BAM_IRQ_SRCS */
+#define BAM_IRQ			BIT(31)
+#define P_IRQ			0x7fffffff
+
+/* BAM_IRQ_SRCS_MSK */
+#define BAM_IRQ_MSK		BAM_IRQ
+#define P_IRQ_MSK		P_IRQ
+
+/* BAM_IRQ_STTS */
+#define BAM_TIMER_IRQ		BIT(4)
+#define BAM_EMPTY_IRQ		BIT(3)
+#define BAM_ERROR_IRQ		BIT(2)
+#define BAM_HRESP_ERR_IRQ	BIT(1)
+
+/* BAM_IRQ_CLR */
+#define BAM_TIMER_CLR		BIT(4)
+#define BAM_EMPTY_CLR		BIT(3)
+#define BAM_ERROR_CLR		BIT(2)
+#define BAM_HRESP_ERR_CLR	BIT(1)
+
+/* BAM_IRQ_EN */
+#define BAM_TIMER_EN		BIT(4)
+#define BAM_EMPTY_EN		BIT(3)
+#define BAM_ERROR_EN		BIT(2)
+#define BAM_HRESP_ERR_EN	BIT(1)
+
+/* BAM_P_IRQ_EN */
+#define P_PRCSD_DESC_EN		BIT(0)
+#define P_TIMER_EN		BIT(1)
+#define P_WAKE_EN		BIT(2)
+#define P_OUT_OF_DESC_EN	BIT(3)
+#define P_ERR_EN		BIT(4)
+#define P_TRNSFR_END_EN		BIT(5)
+#define P_DEFAULT_IRQS_EN	(P_PRCSD_DESC_EN | P_ERR_EN | P_TRNSFR_END_EN)
+
+/* BAM_P_SW_OFSTS */
+#define P_SW_OFSTS_MASK		0xffff
+
+#define BAM_DESC_FIFO_SIZE	SZ_32K
+#define MAX_DESCRIPTORS (BAM_DESC_FIFO_SIZE / sizeof(struct bam_desc_hw) - 1)
+#define BAM_MAX_DATA_SIZE	(SZ_32K - 8)
+
+struct bam_chan {
+	struct virt_dma_chan vc;
+
+	struct bam_device *bdev;
+
+	/* configuration from device tree */
+	u32 id;
+
+	struct bam_async_desc *curr_txd;	/* current running dma */
+
+	/* runtime configuration */
+	struct dma_slave_config slave;
+
+	/* fifo storage */
+	struct bam_desc_hw *fifo_virt;
+	dma_addr_t fifo_phys;
+
+	/* fifo markers */
+	unsigned short head;		/* start of active descriptor entries */
+	unsigned short tail;		/* end of active descriptor entries */
+
+	unsigned int initialized;	/* is the channel hw initialized? */
+	unsigned int paused;		/* is the channel paused? */
+	unsigned int reconfigure;	/* new slave config? */
+
+	struct list_head node;
+};
+
+static inline struct bam_chan *to_bam_chan(struct dma_chan *common)
+{
+	return container_of(common, struct bam_chan, vc.chan);
+}
+
+struct bam_device {
+	void __iomem *regs;
+	struct device *dev;
+	struct dma_device common;
+	struct device_dma_parameters dma_parms;
+	struct bam_chan *channels;
+	u32 num_channels;
+
+	/* execution environment ID, from DT */
+	u32 ee;
+
+	struct clk *bamclk;
+	int irq;
+
+	/* dma start transaction tasklet */
+	struct tasklet_struct task;
+};
+
+/**
+ * bam_reset_channel - Reset individual BAM DMA channel
+ * @bchan: bam channel
+ *
+ * This function resets a specific BAM channel
+ */
+static void bam_reset_channel(struct bam_chan *bchan)
+{
+	struct bam_device *bdev = bchan->bdev;
+
+	lockdep_assert_held(&bchan->vc.lock);
+
+	/* reset channel */
+	writel_relaxed(1, bdev->regs + BAM_P_RST(bchan->id));
+	writel_relaxed(0, bdev->regs + BAM_P_RST(bchan->id));
+
+	/* don't allow cpu to reorder BAM register accesses done after this */
+	wmb();
+
+	/* make sure hw is initialized when channel is used the first time  */
+	bchan->initialized = 0;
+}
+
+/**
+ * bam_chan_init_hw - Initialize channel hardware
+ * @bchan: bam channel
+ *
+ * This function resets and initializes the BAM channel
+ */
+static void bam_chan_init_hw(struct bam_chan *bchan,
+	enum dma_transfer_direction dir)
+{
+	struct bam_device *bdev = bchan->bdev;
+	u32 val;
+
+	/* Reset the channel to clear internal state of the FIFO */
+	bam_reset_channel(bchan);
+
+	/*
+	 * write out 8 byte aligned address.  We have enough space for this
+	 * because we allocated 1 more descriptor (8 bytes) than we can use
+	 */
+	writel_relaxed(ALIGN(bchan->fifo_phys, sizeof(struct bam_desc_hw)),
+			bdev->regs + BAM_P_DESC_FIFO_ADDR(bchan->id));
+	writel_relaxed(BAM_DESC_FIFO_SIZE, bdev->regs +
+			BAM_P_FIFO_SIZES(bchan->id));
+
+	/* enable the per pipe interrupts, enable EOT, ERR, and INT irqs */
+	writel_relaxed(P_DEFAULT_IRQS_EN, bdev->regs + BAM_P_IRQ_EN(bchan->id));
+
+	/* unmask the specific pipe and EE combo */
+	val = readl_relaxed(bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+	val |= BIT(bchan->id);
+	writel_relaxed(val, bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+
+	/* don't allow cpu to reorder the channel enable done below */
+	wmb();
+
+	/* set fixed direction and mode, then enable channel */
+	val = P_EN | P_SYS_MODE;
+	if (dir == DMA_DEV_TO_MEM)
+		val |= P_DIRECTION;
+
+	writel_relaxed(val, bdev->regs + BAM_P_CTRL(bchan->id));
+
+	bchan->initialized = 1;
+
+	/* init FIFO pointers */
+	bchan->head = 0;
+	bchan->tail = 0;
+}
+
+/**
+ * bam_alloc_chan - Allocate channel resources for DMA channel.
+ * @chan: specified channel
+ *
+ * This function allocates the FIFO descriptor memory
+ */
+static int bam_alloc_chan(struct dma_chan *chan)
+{
+	struct bam_chan *bchan = to_bam_chan(chan);
+	struct bam_device *bdev = bchan->bdev;
+
+	if (bchan->fifo_virt)
+		return 0;
+
+	/* allocate FIFO descriptor space, but only if necessary */
+	bchan->fifo_virt = dma_alloc_writecombine(bdev->dev, BAM_DESC_FIFO_SIZE,
+				&bchan->fifo_phys, GFP_KERNEL);
+
+	if (!bchan->fifo_virt) {
+		dev_err(bdev->dev, "Failed to allocate desc fifo\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * bam_free_chan - Frees dma resources associated with specific channel
+ * @chan: specified channel
+ *
+ * Free the allocated fifo descriptor memory and channel resources
+ *
+ */
+static void bam_free_chan(struct dma_chan *chan)
+{
+	struct bam_chan *bchan = to_bam_chan(chan);
+	struct bam_device *bdev = bchan->bdev;
+	u32 val;
+	unsigned long flags;
+
+	vchan_free_chan_resources(to_virt_chan(chan));
+
+	if (bchan->curr_txd) {
+		dev_err(bchan->bdev->dev, "Cannot free busy channel\n");
+		return;
+	}
+
+	spin_lock_irqsave(&bchan->vc.lock, flags);
+	bam_reset_channel(bchan);
+	spin_unlock_irqrestore(&bchan->vc.lock, flags);
+
+	dma_free_writecombine(bdev->dev, BAM_DESC_FIFO_SIZE, bchan->fifo_virt,
+				bchan->fifo_phys);
+	bchan->fifo_virt = NULL;
+
+	/* mask irq for pipe/channel */
+	val = readl_relaxed(bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+	val &= ~BIT(bchan->id);
+	writel_relaxed(val, bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+
+	/* disable irq */
+	writel_relaxed(0, bdev->regs + BAM_P_IRQ_EN(bchan->id));
+}
+
+/**
+ * bam_slave_config - set slave configuration for channel
+ * @chan: dma channel
+ * @cfg: slave configuration
+ *
+ * Sets slave configuration for channel
+ *
+ */
+static void bam_slave_config(struct bam_chan *bchan,
+		struct dma_slave_config *cfg)
+{
+	memcpy(&bchan->slave, cfg, sizeof(*cfg));
+	bchan->reconfigure = 1;
+}
+
+/**
+ * bam_prep_slave_sg - Prep slave sg transaction
+ *
+ * @chan: dma channel
+ * @sgl: scatter gather list
+ * @sg_len: length of sg
+ * @direction: DMA transfer direction
+ * @flags: DMA flags
+ * @context: transfer context (unused)
+ */
+static struct dma_async_tx_descriptor *bam_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 bam_chan *bchan = to_bam_chan(chan);
+	struct bam_device *bdev = bchan->bdev;
+	struct bam_async_desc *async_desc;
+	struct scatterlist *sg;
+	u32 i;
+	struct bam_desc_hw *desc;
+	unsigned int num_alloc = 0;
+
+
+	if (!is_slave_direction(direction)) {
+		dev_err(bdev->dev, "invalid dma direction\n");
+		return NULL;
+	}
+
+	/* calculate number of required entries */
+	for_each_sg(sgl, sg, sg_len, i)
+		num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_MAX_DATA_SIZE);
+
+	/* allocate enough room to accomodate the number of entries */
+	async_desc = kzalloc(sizeof(*async_desc) +
+			(num_alloc * sizeof(struct bam_desc_hw)), GFP_NOWAIT);
+
+	if (!async_desc)
+		goto err_out;
+
+	async_desc->num_desc = num_alloc;
+	async_desc->curr_desc = async_desc->desc;
+	async_desc->dir = direction;
+
+	/* fill in temporary descriptors */
+	desc = async_desc->desc;
+	for_each_sg(sgl, sg, sg_len, i) {
+		unsigned int remainder = sg_dma_len(sg);
+		unsigned int curr_offset = 0;
+
+		do {
+			desc->addr = sg_dma_address(sg) + curr_offset;
+
+			if (remainder > BAM_MAX_DATA_SIZE) {
+				desc->size = BAM_MAX_DATA_SIZE;
+				remainder -= BAM_MAX_DATA_SIZE;
+				curr_offset += BAM_MAX_DATA_SIZE;
+			} else {
+				desc->size = remainder;
+				remainder = 0;
+			}
+
+			async_desc->length += desc->size;
+			desc++;
+		} while (remainder > 0);
+	}
+
+	return vchan_tx_prep(&bchan->vc, &async_desc->vd, flags);
+
+err_out:
+	kfree(async_desc);
+	return NULL;
+}
+
+/**
+ * bam_dma_terminate_all - terminate all transactions on a channel
+ * @bchan: bam dma channel
+ *
+ * Dequeues and frees all transactions
+ * No callbacks are done
+ *
+ */
+static void bam_dma_terminate_all(struct bam_chan *bchan)
+{
+	unsigned long flag;
+	LIST_HEAD(head);
+
+	/* remove all transactions, including active transaction */
+	spin_lock_irqsave(&bchan->vc.lock, flag);
+	if (bchan->curr_txd) {
+		list_add(&bchan->curr_txd->vd.node, &bchan->vc.desc_issued);
+		bchan->curr_txd = NULL;
+	}
+
+	vchan_get_all_descriptors(&bchan->vc, &head);
+	spin_unlock_irqrestore(&bchan->vc.lock, flag);
+
+	vchan_dma_desc_free_list(&bchan->vc, &head);
+}
+
+/**
+ * bam_control - DMA device control
+ * @chan: dma channel
+ * @cmd: control cmd
+ * @arg: cmd argument
+ *
+ * Perform DMA control command
+ *
+ */
+static int bam_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+	unsigned long arg)
+{
+	struct bam_chan *bchan = to_bam_chan(chan);
+	struct bam_device *bdev = bchan->bdev;
+	int ret = 0;
+	unsigned long flag;
+
+	switch (cmd) {
+	case DMA_PAUSE:
+		spin_lock_irqsave(&bchan->vc.lock, flag);
+		writel_relaxed(1, bdev->regs + BAM_P_HALT(bchan->id));
+		bchan->paused = 1;
+		spin_unlock_irqrestore(&bchan->vc.lock, flag);
+		break;
+
+	case DMA_RESUME:
+		spin_lock_irqsave(&bchan->vc.lock, flag);
+		writel_relaxed(0, bdev->regs + BAM_P_HALT(bchan->id));
+		bchan->paused = 0;
+		spin_unlock_irqrestore(&bchan->vc.lock, flag);
+		break;
+
+	case DMA_TERMINATE_ALL:
+		bam_dma_terminate_all(bchan);
+		break;
+
+	case DMA_SLAVE_CONFIG:
+		spin_lock_irqsave(&bchan->vc.lock, flag);
+		bam_slave_config(bchan, (struct dma_slave_config *)arg);
+		spin_unlock_irqrestore(&bchan->vc.lock, flag);
+		break;
+
+	default:
+		ret = -ENXIO;
+		break;
+	}
+
+	return ret;
+}
+
+/**
+ * process_channel_irqs - processes the channel interrupts
+ * @bdev: bam controller
+ *
+ * This function processes the channel interrupts
+ *
+ */
+static u32 process_channel_irqs(struct bam_device *bdev)
+{
+	u32 i, srcs, pipe_stts;
+	unsigned long flags;
+	struct bam_async_desc *async_desc;
+
+	srcs = readl_relaxed(bdev->regs + BAM_IRQ_SRCS_EE(bdev->ee));
+
+	/* return early if no pipe/channel interrupts are present */
+	if (!(srcs & P_IRQ))
+		return srcs;
+
+	for (i = 0; i < bdev->num_channels; i++) {
+		struct bam_chan *bchan = &bdev->channels[i];
+
+		if (!(srcs & BIT(i)))
+			continue;
+
+		/* clear pipe irq */
+		pipe_stts = readl_relaxed(bdev->regs +
+			BAM_P_IRQ_STTS(i));
+
+		writel_relaxed(pipe_stts, bdev->regs +
+				BAM_P_IRQ_CLR(i));
+
+		spin_lock_irqsave(&bchan->vc.lock, flags);
+		async_desc = bchan->curr_txd;
+
+		if (async_desc) {
+			async_desc->num_desc -= async_desc->xfer_len;
+			async_desc->curr_desc += async_desc->xfer_len;
+			bchan->curr_txd = NULL;
+
+			/* manage FIFO */
+			bchan->head += async_desc->xfer_len;
+			bchan->head %= MAX_DESCRIPTORS;
+
+			/*
+			 * if complete, process cookie.  Otherwise
+			 * push back to front of desc_issued so that
+			 * it gets restarted by the tasklet
+			 */
+			if (!async_desc->num_desc)
+				vchan_cookie_complete(&async_desc->vd);
+			else
+				list_add(&async_desc->vd.node,
+					&bchan->vc.desc_issued);
+		}
+
+		spin_unlock_irqrestore(&bchan->vc.lock, flags);
+	}
+
+	return srcs;
+}
+
+/**
+ * bam_dma_irq - irq handler for bam controller
+ * @irq: IRQ of interrupt
+ * @data: callback data
+ *
+ * IRQ handler for the bam controller
+ */
+static irqreturn_t bam_dma_irq(int irq, void *data)
+{
+	struct bam_device *bdev = data;
+	u32 clr_mask = 0, srcs = 0;
+
+	srcs |= process_channel_irqs(bdev);
+
+	/* kick off tasklet to start next dma transfer */
+	if (srcs & P_IRQ)
+		tasklet_schedule(&bdev->task);
+
+	if (srcs & BAM_IRQ)
+		clr_mask = readl_relaxed(bdev->regs + BAM_IRQ_STTS);
+
+	/* don't allow reorder of the various accesses to the BAM registers */
+	mb();
+
+	writel_relaxed(clr_mask, bdev->regs + BAM_IRQ_CLR);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * bam_tx_status - returns status of transaction
+ * @chan: dma channel
+ * @cookie: transaction cookie
+ * @txstate: DMA transaction state
+ *
+ * Return status of dma transaction
+ */
+static enum dma_status bam_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
+		struct dma_tx_state *txstate)
+{
+	struct bam_chan *bchan = to_bam_chan(chan);
+	struct virt_dma_desc *vd;
+	int ret;
+	size_t residue = 0;
+	unsigned int i;
+	unsigned long flags;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	if (!txstate)
+		return bchan->paused ? DMA_PAUSED : ret;
+
+	spin_lock_irqsave(&bchan->vc.lock, flags);
+	vd = vchan_find_desc(&bchan->vc, cookie);
+	if (vd)
+		residue = container_of(vd, struct bam_async_desc, vd)->length;
+	else if (bchan->curr_txd && bchan->curr_txd->vd.tx.cookie == cookie)
+		for (i = 0; i < bchan->curr_txd->num_desc; i++)
+			residue += bchan->curr_txd->curr_desc[i].size;
+
+	spin_unlock_irqrestore(&bchan->vc.lock, flags);
+
+	dma_set_residue(txstate, residue);
+
+	if (ret == DMA_IN_PROGRESS && bchan->paused)
+		ret = DMA_PAUSED;
+
+	return ret;
+}
+
+/**
+ * bam_apply_new_config
+ * @bchan: bam dma channel
+ * @dir: DMA direction
+ */
+static void bam_apply_new_config(struct bam_chan *bchan,
+	enum dma_transfer_direction dir)
+{
+	struct bam_device *bdev = bchan->bdev;
+	u32 maxburst;
+
+	if (dir == DMA_DEV_TO_MEM)
+		maxburst = bchan->slave.src_maxburst;
+	else
+		maxburst = bchan->slave.dst_maxburst;
+
+	writel_relaxed(maxburst, bdev->regs + BAM_DESC_CNT_TRSHLD);
+
+	bchan->reconfigure = 0;
+}
+
+/**
+ * bam_start_dma - start next transaction
+ * @bchan - bam dma channel
+ */
+static void bam_start_dma(struct bam_chan *bchan)
+{
+	struct virt_dma_desc *vd = vchan_next_desc(&bchan->vc);
+	struct bam_device *bdev = bchan->bdev;
+	struct bam_async_desc *async_desc;
+	struct bam_desc_hw *desc;
+	struct bam_desc_hw *fifo = PTR_ALIGN(bchan->fifo_virt,
+					sizeof(struct bam_desc_hw));
+
+	lockdep_assert_held(&bchan->vc.lock);
+
+	if (!vd)
+		return;
+
+	list_del(&vd->node);
+
+	async_desc = container_of(vd, struct bam_async_desc, vd);
+	bchan->curr_txd = async_desc;
+
+	/* on first use, initialize the channel hardware */
+	if (!bchan->initialized)
+		bam_chan_init_hw(bchan, async_desc->dir);
+
+	/* apply new slave config changes, if necessary */
+	if (bchan->reconfigure)
+		bam_apply_new_config(bchan, async_desc->dir);
+
+	desc = bchan->curr_txd->curr_desc;
+
+	if (async_desc->num_desc > MAX_DESCRIPTORS)
+		async_desc->xfer_len = MAX_DESCRIPTORS;
+	else
+		async_desc->xfer_len = async_desc->num_desc;
+
+	/* set INT on last descriptor */
+	desc[async_desc->xfer_len - 1].flags |= DESC_FLAG_INT;
+
+	if (bchan->tail + async_desc->xfer_len > MAX_DESCRIPTORS) {
+		u32 partial = MAX_DESCRIPTORS - bchan->tail;
+
+		memcpy(&fifo[bchan->tail], desc,
+				partial * sizeof(struct bam_desc_hw));
+		memcpy(fifo, &desc[partial], (async_desc->xfer_len - partial) *
+				sizeof(struct bam_desc_hw));
+	} else {
+		memcpy(&fifo[bchan->tail], desc,
+			async_desc->xfer_len * sizeof(struct bam_desc_hw));
+	}
+
+	bchan->tail += async_desc->xfer_len;
+	bchan->tail %= MAX_DESCRIPTORS;
+
+	/* ensure descriptor writes and dma start not reordered */
+	wmb();
+	writel_relaxed(bchan->tail * sizeof(struct bam_desc_hw),
+			bdev->regs + BAM_P_EVNT_REG(bchan->id));
+}
+
+/**
+ * dma_tasklet - DMA IRQ tasklet
+ * @data: tasklet argument (bam controller structure)
+ *
+ * Sets up next DMA operation and then processes all completed transactions
+ */
+static void dma_tasklet(unsigned long data)
+{
+	struct bam_device *bdev = (struct bam_device *)data;
+	struct bam_chan *bchan;
+	unsigned long flags;
+	unsigned int i;
+
+	/* go through the channels and kick off transactions */
+	for (i = 0; i < bdev->num_channels; i++) {
+		bchan = &bdev->channels[i];
+		spin_lock_irqsave(&bchan->vc.lock, flags);
+
+		if (!list_empty(&bchan->vc.desc_issued) && !bchan->curr_txd)
+			bam_start_dma(bchan);
+		spin_unlock_irqrestore(&bchan->vc.lock, flags);
+	}
+}
+
+/**
+ * bam_issue_pending - starts pending transactions
+ * @chan: dma channel
+ *
+ * Calls tasklet directly which in turn starts any pending transactions
+ */
+static void bam_issue_pending(struct dma_chan *chan)
+{
+	struct bam_chan *bchan = to_bam_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&bchan->vc.lock, flags);
+
+	/* if work pending and idle, start a transaction */
+	if (vchan_issue_pending(&bchan->vc) && !bchan->curr_txd)
+		bam_start_dma(bchan);
+
+	spin_unlock_irqrestore(&bchan->vc.lock, flags);
+}
+
+/**
+ * bam_dma_free_desc - free descriptor memory
+ * @vd: virtual descriptor
+ *
+ */
+static void bam_dma_free_desc(struct virt_dma_desc *vd)
+{
+	struct bam_async_desc *async_desc = container_of(vd,
+			struct bam_async_desc, vd);
+
+	kfree(async_desc);
+}
+
+static struct dma_chan *bam_dma_xlate(struct of_phandle_args *dma_spec,
+		struct of_dma *of)
+{
+	struct bam_device *bdev = container_of(of->of_dma_data,
+					struct bam_device, common);
+	unsigned int request;
+
+	if (dma_spec->args_count != 1)
+		return NULL;
+
+	request = dma_spec->args[0];
+	if (request >= bdev->num_channels)
+		return NULL;
+
+	return dma_get_slave_channel(&(bdev->channels[request].vc.chan));
+}
+
+/**
+ * bam_init
+ * @bdev: bam device
+ *
+ * Initialization helper for global bam registers
+ */
+static int bam_init(struct bam_device *bdev)
+{
+	u32 val;
+
+	/* read revision and configuration information */
+	val = readl_relaxed(bdev->regs + BAM_REVISION) >> NUM_EES_SHIFT;
+	val &= NUM_EES_MASK;
+
+	/* check that configured EE is within range */
+	if (bdev->ee >= val)
+		return -EINVAL;
+
+	val = readl_relaxed(bdev->regs + BAM_NUM_PIPES);
+	bdev->num_channels = val & BAM_NUM_PIPES_MASK;
+
+	/* s/w reset bam */
+	/* after reset all pipes are disabled and idle */
+	val = readl_relaxed(bdev->regs + BAM_CTRL);
+	val |= BAM_SW_RST;
+	writel_relaxed(val, bdev->regs + BAM_CTRL);
+	val &= ~BAM_SW_RST;
+	writel_relaxed(val, bdev->regs + BAM_CTRL);
+
+	/* make sure previous stores are visible before enabling BAM */
+	wmb();
+
+	/* enable bam */
+	val |= BAM_EN;
+	writel_relaxed(val, bdev->regs + BAM_CTRL);
+
+	/* set descriptor threshhold, start with 4 bytes */
+	writel_relaxed(DEFAULT_CNT_THRSHLD, bdev->regs + BAM_DESC_CNT_TRSHLD);
+
+	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
+	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bdev->regs + BAM_CNFG_BITS);
+
+	/* enable irqs for errors */
+	writel_relaxed(BAM_ERROR_EN | BAM_HRESP_ERR_EN,
+				bdev->regs + BAM_IRQ_EN);
+
+	/* unmask global bam interrupt */
+	writel_relaxed(BAM_IRQ_MSK, bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+
+	return 0;
+}
+
+static void bam_channel_init(struct bam_device *bdev, struct bam_chan *bchan,
+	u32 index)
+{
+	bchan->id = index;
+	bchan->bdev = bdev;
+
+	vchan_init(&bchan->vc, &bdev->common);
+	bchan->vc.desc_free = bam_dma_free_desc;
+}
+
+static int bam_dma_probe(struct platform_device *pdev)
+{
+	struct bam_device *bdev;
+	struct resource *iores;
+	int ret, i;
+
+	bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
+	if (!bdev)
+		return -ENOMEM;
+
+	bdev->dev = &pdev->dev;
+
+	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	bdev->regs = devm_ioremap_resource(&pdev->dev, iores);
+	if (IS_ERR(bdev->regs))
+		return PTR_ERR(bdev->regs);
+
+	bdev->irq = platform_get_irq(pdev, 0);
+	if (bdev->irq < 0)
+		return bdev->irq;
+
+	ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &bdev->ee);
+	if (ret) {
+		dev_err(bdev->dev, "Execution environment unspecified\n");
+		return ret;
+	}
+
+	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
+	if (IS_ERR(bdev->bamclk))
+		return PTR_ERR(bdev->bamclk);
+
+	ret = clk_prepare_enable(bdev->bamclk);
+	if (ret) {
+		dev_err(bdev->dev, "failed to prepare/enable clock\n");
+		return ret;
+	}
+
+	ret = bam_init(bdev);
+	if (ret)
+		goto err_disable_clk;
+
+	tasklet_init(&bdev->task, dma_tasklet, (unsigned long)bdev);
+
+	bdev->channels = devm_kcalloc(bdev->dev, bdev->num_channels,
+				sizeof(*bdev->channels), GFP_KERNEL);
+
+	if (!bdev->channels) {
+		ret = -ENOMEM;
+		goto err_disable_clk;
+	}
+
+	/* allocate and initialize channels */
+	INIT_LIST_HEAD(&bdev->common.channels);
+
+	for (i = 0; i < bdev->num_channels; i++)
+		bam_channel_init(bdev, &bdev->channels[i], i);
+
+	ret = devm_request_irq(bdev->dev, bdev->irq, bam_dma_irq,
+			IRQF_TRIGGER_HIGH, "bam_dma", bdev);
+	if (ret)
+		goto err_disable_clk;
+
+	/* set max dma segment size */
+	bdev->common.dev = bdev->dev;
+	bdev->common.dev->dma_parms = &bdev->dma_parms;
+	ret = dma_set_max_seg_size(bdev->common.dev, BAM_MAX_DATA_SIZE);
+	if (ret) {
+		dev_err(bdev->dev, "cannot set maximum segment size\n");
+		goto err_disable_clk;
+	}
+
+	platform_set_drvdata(pdev, bdev);
+
+	/* set capabilities */
+	dma_cap_zero(bdev->common.cap_mask);
+	dma_cap_set(DMA_SLAVE, bdev->common.cap_mask);
+
+	/* initialize dmaengine apis */
+	bdev->common.device_alloc_chan_resources = bam_alloc_chan;
+	bdev->common.device_free_chan_resources = bam_free_chan;
+	bdev->common.device_prep_slave_sg = bam_prep_slave_sg;
+	bdev->common.device_control = bam_control;
+	bdev->common.device_issue_pending = bam_issue_pending;
+	bdev->common.device_tx_status = bam_tx_status;
+	bdev->common.dev = bdev->dev;
+
+	ret = dma_async_device_register(&bdev->common);
+	if (ret) {
+		dev_err(bdev->dev, "failed to register dma async device\n");
+		goto err_disable_clk;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node, bam_dma_xlate,
+					&bdev->common);
+	if (ret)
+		goto err_unregister_dma;
+
+	return 0;
+
+err_unregister_dma:
+	dma_async_device_unregister(&bdev->common);
+err_disable_clk:
+	clk_disable_unprepare(bdev->bamclk);
+	return ret;
+}
+
+static int bam_dma_remove(struct platform_device *pdev)
+{
+	struct bam_device *bdev = platform_get_drvdata(pdev);
+	u32 i;
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&bdev->common);
+
+	/* mask all interrupts for this execution environment */
+	writel_relaxed(0, bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
+
+	devm_free_irq(bdev->dev, bdev->irq, bdev);
+
+	for (i = 0; i < bdev->num_channels; i++) {
+		bam_dma_terminate_all(&bdev->channels[i]);
+		tasklet_kill(&bdev->channels[i].vc.task);
+
+		dma_free_writecombine(bdev->dev, BAM_DESC_FIFO_SIZE,
+			bdev->channels[i].fifo_virt,
+			bdev->channels[i].fifo_phys);
+	}
+
+	tasklet_kill(&bdev->task);
+
+	clk_disable_unprepare(bdev->bamclk);
+
+	return 0;
+}
+
+static const struct of_device_id bam_of_match[] = {
+	{ .compatible = "qcom,bam-v1.4.0", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, bam_of_match);
+
+static struct platform_driver bam_dma_driver = {
+	.probe = bam_dma_probe,
+	.remove = bam_dma_remove,
+	.driver = {
+		.name = "bam-dma-engine",
+		.owner = THIS_MODULE,
+		.of_match_table = bam_of_match,
+	},
+};
+
+module_platform_driver(bam_dma_driver);
+
+MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
+MODULE_DESCRIPTION("QCOM BAM DMA engine driver");
+MODULE_LICENSE("GPL v2");