usb: Add MediaTek USB3 DRD driver

This patch adds support for the MediaTek USB3 controller
integrated into MT8173. It currently supports High-Speed
Peripheral Only mode.

Super-Speed Peripheral, Dual-Role Device and Host Only (xHCI)
modes will be added in the next patchs.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 573 insertions, 0 deletions

diff --git a/drivers/usb/mtu3/mtu3_qmu.c b/drivers/usb/mtu3/mtu3_qmu.c
new file mode 100644
index 000000000000..a6dd292c63ec
--- /dev/null
+++ b/drivers/usb/mtu3/mtu3_qmu.c
@@ -0,0 +1,573 @@
+/*
+ * mtu3_qmu.c - Queue Management Unit driver for device controller
+ *
+ * Copyright (C) 2016 MediaTek Inc.
+ *
+ * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/*
+ * Queue Management Unit (QMU) is designed to unload SW effort
+ * to serve DMA interrupts.
+ * By preparing General Purpose Descriptor (GPD) and Buffer Descriptor (BD),
+ * SW links data buffers and triggers QMU to send / receive data to
+ * host / from device at a time.
+ * And now only GPD is supported.
+ *
+ * For more detailed information, please refer to QMU Programming Guide
+ */
+
+#include <linux/dmapool.h>
+#include <linux/iopoll.h>
+
+#include "mtu3.h"
+
+#define QMU_CHECKSUM_LEN	16
+
+#define GPD_FLAGS_HWO	BIT(0)
+#define GPD_FLAGS_BDP	BIT(1)
+#define GPD_FLAGS_BPS	BIT(2)
+#define GPD_FLAGS_IOC	BIT(7)
+
+#define GPD_EXT_FLAG_ZLP	BIT(5)
+
+
+static struct qmu_gpd *gpd_dma_to_virt(struct mtu3_gpd_ring *ring,
+		dma_addr_t dma_addr)
+{
+	dma_addr_t dma_base = ring->dma;
+	struct qmu_gpd *gpd_head = ring->start;
+	u32 offset = (dma_addr - dma_base) / sizeof(*gpd_head);
+
+	if (offset >= MAX_GPD_NUM)
+		return NULL;
+
+	return gpd_head + offset;
+}
+
+static dma_addr_t gpd_virt_to_dma(struct mtu3_gpd_ring *ring,
+		struct qmu_gpd *gpd)
+{
+	dma_addr_t dma_base = ring->dma;
+	struct qmu_gpd *gpd_head = ring->start;
+	u32 offset;
+
+	offset = gpd - gpd_head;
+	if (offset >= MAX_GPD_NUM)
+		return 0;
+
+	return dma_base + (offset * sizeof(*gpd));
+}
+
+static void gpd_ring_init(struct mtu3_gpd_ring *ring, struct qmu_gpd *gpd)
+{
+	ring->start = gpd;
+	ring->enqueue = gpd;
+	ring->dequeue = gpd;
+	ring->end = gpd + MAX_GPD_NUM - 1;
+}
+
+static void reset_gpd_list(struct mtu3_ep *mep)
+{
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	struct qmu_gpd *gpd = ring->start;
+
+	if (gpd) {
+		gpd->flag &= ~GPD_FLAGS_HWO;
+		gpd_ring_init(ring, gpd);
+	}
+}
+
+int mtu3_gpd_ring_alloc(struct mtu3_ep *mep)
+{
+	struct qmu_gpd *gpd;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+
+	/* software own all gpds as default */
+	gpd = dma_pool_zalloc(mep->mtu->qmu_gpd_pool, GFP_ATOMIC, &ring->dma);
+	if (gpd == NULL)
+		return -ENOMEM;
+
+	gpd_ring_init(ring, gpd);
+
+	return 0;
+}
+
+void mtu3_gpd_ring_free(struct mtu3_ep *mep)
+{
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+
+	dma_pool_free(mep->mtu->qmu_gpd_pool,
+			ring->start, ring->dma);
+	memset(ring, 0, sizeof(*ring));
+}
+
+/*
+ * calculate check sum of a gpd or bd
+ * add "noinline" and "mb" to prevent wrong calculation
+ */
+static noinline u8 qmu_calc_checksum(u8 *data)
+{
+	u8 chksum = 0;
+	int i;
+
+	data[1] = 0x0;  /* set checksum to 0 */
+
+	mb();	/* ensure the gpd/bd is really up-to-date */
+	for (i = 0; i < QMU_CHECKSUM_LEN; i++)
+		chksum += data[i];
+
+	/* Default: HWO=1, @flag[bit0] */
+	chksum += 1;
+
+	return 0xFF - chksum;
+}
+
+void mtu3_qmu_resume(struct mtu3_ep *mep)
+{
+	struct mtu3 *mtu = mep->mtu;
+	void __iomem *mbase = mtu->mac_base;
+	int epnum = mep->epnum;
+	u32 offset;
+
+	offset = mep->is_in ? USB_QMU_TQCSR(epnum) : USB_QMU_RQCSR(epnum);
+
+	mtu3_writel(mbase, offset, QMU_Q_RESUME);
+	if (!(mtu3_readl(mbase, offset) & QMU_Q_ACTIVE))
+		mtu3_writel(mbase, offset, QMU_Q_RESUME);
+}
+
+static struct qmu_gpd *advance_enq_gpd(struct mtu3_gpd_ring *ring)
+{
+	if (ring->enqueue < ring->end)
+		ring->enqueue++;
+	else
+		ring->enqueue = ring->start;
+
+	return ring->enqueue;
+}
+
+static struct qmu_gpd *advance_deq_gpd(struct mtu3_gpd_ring *ring)
+{
+	if (ring->dequeue < ring->end)
+		ring->dequeue++;
+	else
+		ring->dequeue = ring->start;
+
+	return ring->dequeue;
+}
+
+/* check if a ring is emtpy */
+int gpd_ring_empty(struct mtu3_gpd_ring *ring)
+{
+	struct qmu_gpd *enq = ring->enqueue;
+	struct qmu_gpd *next;
+
+	if (ring->enqueue < ring->end)
+		next = enq + 1;
+	else
+		next = ring->start;
+
+	/* one gpd is reserved to simplify gpd preparation */
+	return next == ring->dequeue;
+}
+
+int mtu3_prepare_transfer(struct mtu3_ep *mep)
+{
+	return gpd_ring_empty(&mep->gpd_ring);
+}
+
+static int mtu3_prepare_tx_gpd(struct mtu3_ep *mep, struct mtu3_request *mreq)
+{
+	struct qmu_gpd *enq;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	struct qmu_gpd *gpd = ring->enqueue;
+	struct usb_request *req = &mreq->request;
+
+	/* set all fields to zero as default value */
+	memset(gpd, 0, sizeof(*gpd));
+
+	gpd->buffer = cpu_to_le32((u32)req->dma);
+	gpd->buf_len = cpu_to_le16(req->length);
+	gpd->flag |= GPD_FLAGS_IOC;
+
+	/* get the next GPD */
+	enq = advance_enq_gpd(ring);
+	dev_dbg(mep->mtu->dev, "TX-EP%d queue gpd=%p, enq=%p\n",
+		mep->epnum, gpd, enq);
+
+	enq->flag &= ~GPD_FLAGS_HWO;
+	gpd->next_gpd = cpu_to_le32((u32)gpd_virt_to_dma(ring, enq));
+
+	if (req->zero)
+		gpd->ext_flag |= GPD_EXT_FLAG_ZLP;
+
+	gpd->chksum = qmu_calc_checksum((u8 *)gpd);
+	gpd->flag |= GPD_FLAGS_HWO;
+
+	mreq->gpd = gpd;
+
+	return 0;
+}
+
+static int mtu3_prepare_rx_gpd(struct mtu3_ep *mep, struct mtu3_request *mreq)
+{
+	struct qmu_gpd *enq;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	struct qmu_gpd *gpd = ring->enqueue;
+	struct usb_request *req = &mreq->request;
+
+	/* set all fields to zero as default value */
+	memset(gpd, 0, sizeof(*gpd));
+
+	gpd->buffer = cpu_to_le32((u32)req->dma);
+	gpd->data_buf_len = cpu_to_le16(req->length);
+	gpd->flag |= GPD_FLAGS_IOC;
+
+	/* get the next GPD */
+	enq = advance_enq_gpd(ring);
+	dev_dbg(mep->mtu->dev, "RX-EP%d queue gpd=%p, enq=%p\n",
+		mep->epnum, gpd, enq);
+
+	enq->flag &= ~GPD_FLAGS_HWO;
+	gpd->next_gpd = cpu_to_le32((u32)gpd_virt_to_dma(ring, enq));
+	gpd->chksum = qmu_calc_checksum((u8 *)gpd);
+	gpd->flag |= GPD_FLAGS_HWO;
+
+	mreq->gpd = gpd;
+
+	return 0;
+}
+
+void mtu3_insert_gpd(struct mtu3_ep *mep, struct mtu3_request *mreq)
+{
+
+	if (mep->is_in)
+		mtu3_prepare_tx_gpd(mep, mreq);
+	else
+		mtu3_prepare_rx_gpd(mep, mreq);
+}
+
+int mtu3_qmu_start(struct mtu3_ep *mep)
+{
+	struct mtu3 *mtu = mep->mtu;
+	void __iomem *mbase = mtu->mac_base;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	u8 epnum = mep->epnum;
+
+	if (mep->is_in) {
+		/* set QMU start address */
+		mtu3_writel(mbase, USB_QMU_TQSAR(mep->epnum), ring->dma);
+		mtu3_setbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_DMAREQEN);
+		mtu3_setbits(mbase, U3D_QCR0, QMU_TX_CS_EN(epnum));
+		/* send zero length packet according to ZLP flag in GPD */
+		mtu3_setbits(mbase, U3D_QCR1, QMU_TX_ZLP(epnum));
+		mtu3_writel(mbase, U3D_TQERRIESR0,
+				QMU_TX_LEN_ERR(epnum) | QMU_TX_CS_ERR(epnum));
+
+		if (mtu3_readl(mbase, USB_QMU_TQCSR(epnum)) & QMU_Q_ACTIVE) {
+			dev_warn(mtu->dev, "Tx %d Active Now!\n", epnum);
+			return 0;
+		}
+		mtu3_writel(mbase, USB_QMU_TQCSR(epnum), QMU_Q_START);
+
+	} else {
+		mtu3_writel(mbase, USB_QMU_RQSAR(mep->epnum), ring->dma);
+		mtu3_setbits(mbase, MU3D_EP_RXCR0(mep->epnum), RX_DMAREQEN);
+		mtu3_setbits(mbase, U3D_QCR0, QMU_RX_CS_EN(epnum));
+		/* don't expect ZLP */
+		mtu3_clrbits(mbase, U3D_QCR3, QMU_RX_ZLP(epnum));
+		/* move to next GPD when receive ZLP */
+		mtu3_setbits(mbase, U3D_QCR3, QMU_RX_COZ(epnum));
+		mtu3_writel(mbase, U3D_RQERRIESR0,
+				QMU_RX_LEN_ERR(epnum) | QMU_RX_CS_ERR(epnum));
+		mtu3_writel(mbase, U3D_RQERRIESR1, QMU_RX_ZLP_ERR(epnum));
+
+		if (mtu3_readl(mbase, USB_QMU_RQCSR(epnum)) & QMU_Q_ACTIVE) {
+			dev_warn(mtu->dev, "Rx %d Active Now!\n", epnum);
+			return 0;
+		}
+		mtu3_writel(mbase, USB_QMU_RQCSR(epnum), QMU_Q_START);
+	}
+
+	return 0;
+}
+
+/* may called in atomic context */
+void mtu3_qmu_stop(struct mtu3_ep *mep)
+{
+	struct mtu3 *mtu = mep->mtu;
+	void __iomem *mbase = mtu->mac_base;
+	int epnum = mep->epnum;
+	u32 value = 0;
+	u32 qcsr;
+	int ret;
+
+	qcsr = mep->is_in ? USB_QMU_TQCSR(epnum) : USB_QMU_RQCSR(epnum);
+
+	if (!(mtu3_readl(mbase, qcsr) & QMU_Q_ACTIVE)) {
+		dev_dbg(mtu->dev, "%s's qmu is inactive now!\n", mep->name);
+		return;
+	}
+	mtu3_writel(mbase, qcsr, QMU_Q_STOP);
+
+	ret = readl_poll_timeout_atomic(mbase + qcsr, value,
+			!(value & QMU_Q_ACTIVE), 1, 1000);
+	if (ret) {
+		dev_err(mtu->dev, "stop %s's qmu failed\n", mep->name);
+		return;
+	}
+
+	dev_dbg(mtu->dev, "%s's qmu stop now!\n", mep->name);
+}
+
+void mtu3_qmu_flush(struct mtu3_ep *mep)
+{
+
+	dev_dbg(mep->mtu->dev, "%s flush QMU %s\n", __func__,
+		((mep->is_in) ? "TX" : "RX"));
+
+	/*Stop QMU */
+	mtu3_qmu_stop(mep);
+	reset_gpd_list(mep);
+}
+
+/*
+ * QMU can't transfer zero length packet directly (a hardware limit
+ * on old SoCs), so when needs to send ZLP, we intentionally trigger
+ * a length error interrupt, and in the ISR sends a ZLP by BMU.
+ */
+static void qmu_tx_zlp_error_handler(struct mtu3 *mtu, u8 epnum)
+{
+	struct mtu3_ep *mep = mtu->in_eps + epnum;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	void __iomem *mbase = mtu->mac_base;
+	struct qmu_gpd *gpd_current = NULL;
+	dma_addr_t gpd_dma = mtu3_readl(mbase, USB_QMU_TQCPR(epnum));
+	struct usb_request *req = NULL;
+	struct mtu3_request *mreq;
+	u32 txcsr = 0;
+	int ret;
+
+	mreq = next_request(mep);
+	if (mreq && mreq->request.length == 0)
+		req = &mreq->request;
+	else
+		return;
+
+	gpd_current = gpd_dma_to_virt(ring, gpd_dma);
+
+	if (le16_to_cpu(gpd_current->buf_len) != 0) {
+		dev_err(mtu->dev, "TX EP%d buffer length error(!=0)\n", epnum);
+		return;
+	}
+
+	dev_dbg(mtu->dev, "%s send ZLP for req=%p\n", __func__, mreq);
+
+	mtu3_clrbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_DMAREQEN);
+
+	ret = readl_poll_timeout_atomic(mbase + MU3D_EP_TXCR0(mep->epnum),
+			txcsr, !(txcsr & TX_FIFOFULL), 1, 1000);
+	if (ret) {
+		dev_err(mtu->dev, "%s wait for fifo empty fail\n", __func__);
+		return;
+	}
+	mtu3_setbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_TXPKTRDY);
+
+	/* by pass the current GDP */
+	gpd_current->flag |= GPD_FLAGS_BPS;
+	gpd_current->chksum = qmu_calc_checksum((u8 *)gpd_current);
+	gpd_current->flag |= GPD_FLAGS_HWO;
+
+	/*enable DMAREQEN, switch back to QMU mode */
+	mtu3_setbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_DMAREQEN);
+	mtu3_qmu_resume(mep);
+}
+
+/*
+ * NOTE: request list maybe is already empty as following case:
+ * queue_tx --> qmu_interrupt(clear interrupt pending, schedule tasklet)-->
+ * queue_tx --> process_tasklet(meanwhile, the second one is transferred,
+ * tasklet process both of them)-->qmu_interrupt for second one.
+ * To avoid upper case, put qmu_done_tx in ISR directly to process it.
+ */
+static void qmu_done_tx(struct mtu3 *mtu, u8 epnum)
+{
+	struct mtu3_ep *mep = mtu->in_eps + epnum;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	void __iomem *mbase = mtu->mac_base;
+	struct qmu_gpd *gpd = ring->dequeue;
+	struct qmu_gpd *gpd_current = NULL;
+	dma_addr_t gpd_dma = mtu3_readl(mbase, USB_QMU_TQCPR(epnum));
+	struct usb_request *request = NULL;
+	struct mtu3_request *mreq;
+
+	/*transfer phy address got from QMU register to virtual address */
+	gpd_current = gpd_dma_to_virt(ring, gpd_dma);
+
+	dev_dbg(mtu->dev, "%s EP%d, last=%p, current=%p, enq=%p\n",
+		__func__, epnum, gpd, gpd_current, ring->enqueue);
+
+	while (gpd != gpd_current && !(gpd->flag & GPD_FLAGS_HWO)) {
+
+		mreq = next_request(mep);
+
+		if (mreq == NULL || mreq->gpd != gpd) {
+			dev_err(mtu->dev, "no correct TX req is found\n");
+			break;
+		}
+
+		request = &mreq->request;
+		request->actual = le16_to_cpu(gpd->buf_len);
+		mtu3_req_complete(mep, request, 0);
+
+		gpd = advance_deq_gpd(ring);
+	}
+
+	dev_dbg(mtu->dev, "%s EP%d, deq=%p, enq=%p, complete\n",
+		__func__, epnum, ring->dequeue, ring->enqueue);
+
+}
+
+static void qmu_done_rx(struct mtu3 *mtu, u8 epnum)
+{
+	struct mtu3_ep *mep = mtu->out_eps + epnum;
+	struct mtu3_gpd_ring *ring = &mep->gpd_ring;
+	void __iomem *mbase = mtu->mac_base;
+	struct qmu_gpd *gpd = ring->dequeue;
+	struct qmu_gpd *gpd_current = NULL;
+	dma_addr_t gpd_dma = mtu3_readl(mbase, USB_QMU_RQCPR(epnum));
+	struct usb_request *req = NULL;
+	struct mtu3_request *mreq;
+
+	gpd_current = gpd_dma_to_virt(ring, gpd_dma);
+
+	dev_dbg(mtu->dev, "%s EP%d, last=%p, current=%p, enq=%p\n",
+		__func__, epnum, gpd, gpd_current, ring->enqueue);
+
+	while (gpd != gpd_current && !(gpd->flag & GPD_FLAGS_HWO)) {
+
+		mreq = next_request(mep);
+
+		if (mreq == NULL || mreq->gpd != gpd) {
+			dev_err(mtu->dev, "no correct RX req is found\n");
+			break;
+		}
+		req = &mreq->request;
+
+		req->actual = le16_to_cpu(gpd->buf_len);
+		mtu3_req_complete(mep, req, 0);
+
+		gpd = advance_deq_gpd(ring);
+	}
+
+	dev_dbg(mtu->dev, "%s EP%d, deq=%p, enq=%p, complete\n",
+		__func__, epnum, ring->dequeue, ring->enqueue);
+}
+
+static void qmu_done_isr(struct mtu3 *mtu, u32 done_status)
+{
+	int i;
+
+	for (i = 1; i < mtu->num_eps; i++) {
+		if (done_status & QMU_RX_DONE_INT(i))
+			qmu_done_rx(mtu, i);
+		if (done_status & QMU_TX_DONE_INT(i))
+			qmu_done_tx(mtu, i);
+	}
+}
+
+static void qmu_exception_isr(struct mtu3 *mtu, u32 qmu_status)
+{
+	void __iomem *mbase = mtu->mac_base;
+	u32 errval;
+	int i;
+
+	if ((qmu_status & RXQ_CSERR_INT) || (qmu_status & RXQ_LENERR_INT)) {
+		errval = mtu3_readl(mbase, U3D_RQERRIR0);
+		for (i = 1; i < mtu->num_eps; i++) {
+			if (errval & QMU_RX_CS_ERR(i))
+				dev_err(mtu->dev, "Rx %d CS error!\n", i);
+
+			if (errval & QMU_RX_LEN_ERR(i))
+				dev_err(mtu->dev, "RX %d Length error\n", i);
+		}
+		mtu3_writel(mbase, U3D_RQERRIR0, errval);
+	}
+
+	if (qmu_status & RXQ_ZLPERR_INT) {
+		errval = mtu3_readl(mbase, U3D_RQERRIR1);
+		for (i = 1; i < mtu->num_eps; i++) {
+			if (errval & QMU_RX_ZLP_ERR(i))
+				dev_dbg(mtu->dev, "RX EP%d Recv ZLP\n", i);
+		}
+		mtu3_writel(mbase, U3D_RQERRIR1, errval);
+	}
+
+	if ((qmu_status & TXQ_CSERR_INT) || (qmu_status & TXQ_LENERR_INT)) {
+		errval = mtu3_readl(mbase, U3D_TQERRIR0);
+		for (i = 1; i < mtu->num_eps; i++) {
+			if (errval & QMU_TX_CS_ERR(i))
+				dev_err(mtu->dev, "Tx %d checksum error!\n", i);
+
+			if (errval & QMU_TX_LEN_ERR(i))
+				qmu_tx_zlp_error_handler(mtu, i);
+		}
+		mtu3_writel(mbase, U3D_TQERRIR0, errval);
+	}
+}
+
+irqreturn_t mtu3_qmu_isr(struct mtu3 *mtu)
+{
+	void __iomem *mbase = mtu->mac_base;
+	u32 qmu_status;
+	u32 qmu_done_status;
+
+	/* U3D_QISAR1 is read update */
+	qmu_status = mtu3_readl(mbase, U3D_QISAR1);
+	qmu_status &= mtu3_readl(mbase, U3D_QIER1);
+
+	qmu_done_status = mtu3_readl(mbase, U3D_QISAR0);
+	qmu_done_status &= mtu3_readl(mbase, U3D_QIER0);
+	mtu3_writel(mbase, U3D_QISAR0, qmu_done_status); /* W1C */
+	dev_dbg(mtu->dev, "=== QMUdone[tx=%x, rx=%x] QMUexp[%x] ===\n",
+		(qmu_done_status & 0xFFFF), qmu_done_status >> 16,
+		qmu_status);
+
+	if (qmu_done_status)
+		qmu_done_isr(mtu, qmu_done_status);
+
+	if (qmu_status)
+		qmu_exception_isr(mtu, qmu_status);
+
+	return IRQ_HANDLED;
+}
+
+int mtu3_qmu_init(struct mtu3 *mtu)
+{
+
+	compiletime_assert(QMU_GPD_SIZE == 16, "QMU_GPD size SHOULD be 16B");
+
+	mtu->qmu_gpd_pool = dma_pool_create("QMU_GPD", mtu->dev,
+			QMU_GPD_RING_SIZE, QMU_GPD_SIZE, 0);
+
+	if (!mtu->qmu_gpd_pool)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void mtu3_qmu_exit(struct mtu3 *mtu)
+{
+	dma_pool_destroy(mtu->qmu_gpd_pool);
+}