drivers/usb/mtu3/mtu3_qmu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * mtu3_qmu.c - Queue Management Unit driver for device controller
  *
  * Copyright (C) 2016 MediaTek Inc.
  *
  * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
  */

 /*
  * 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)
 #define GPD_EXT_NGP(x)		(((x) & 0xf) << 4)
 #define GPD_EXT_BUF(x)		(((x) & 0xf) << 0)

 #define HILO_GEN64(hi, lo) (((u64)(hi) << 32) + (lo))
 #define HILO_DMA(hi, lo)	\
 	((dma_addr_t)HILO_GEN64((le32_to_cpu(hi)), (le32_to_cpu(lo))))

 static dma_addr_t read_txq_cur_addr(void __iomem *mbase, u8 epnum)
 {
 	u32 txcpr;
 	u32 txhiar;

 	txcpr = mtu3_readl(mbase, USB_QMU_TQCPR(epnum));
 	txhiar = mtu3_readl(mbase, USB_QMU_TQHIAR(epnum));

 	return HILO_DMA(QMU_CUR_GPD_ADDR_HI(txhiar), txcpr);
 }

 static dma_addr_t read_rxq_cur_addr(void __iomem *mbase, u8 epnum)
 {
 	u32 rxcpr;
 	u32 rxhiar;

 	rxcpr = mtu3_readl(mbase, USB_QMU_RQCPR(epnum));
 	rxhiar = mtu3_readl(mbase, USB_QMU_RQHIAR(epnum));

 	return HILO_DMA(QMU_CUR_GPD_ADDR_HI(rxhiar), rxcpr);
 }

 static void write_txq_start_addr(void __iomem *mbase, u8 epnum, dma_addr_t dma)
 {
 	u32 tqhiar;

 	mtu3_writel(mbase, USB_QMU_TQSAR(epnum),
 		    cpu_to_le32(lower_32_bits(dma)));
 	tqhiar = mtu3_readl(mbase, USB_QMU_TQHIAR(epnum));
 	tqhiar &= ~QMU_START_ADDR_HI_MSK;
 	tqhiar |= QMU_START_ADDR_HI(upper_32_bits(dma));
 	mtu3_writel(mbase, USB_QMU_TQHIAR(epnum), tqhiar);
 }

 static void write_rxq_start_addr(void __iomem *mbase, u8 epnum, dma_addr_t dma)
 {
 	u32 rqhiar;

 	mtu3_writel(mbase, USB_QMU_RQSAR(epnum),
 		    cpu_to_le32(lower_32_bits(dma)));
 	rqhiar = mtu3_readl(mbase, USB_QMU_RQHIAR(epnum));
 	rqhiar &= ~QMU_START_ADDR_HI_MSK;
 	rqhiar |= QMU_START_ADDR_HI(upper_32_bits(dma));
 	mtu3_writel(mbase, USB_QMU_RQHIAR(epnum), rqhiar);
 }

 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));
 }

 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 */
 static 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;
 	dma_addr_t enq_dma;
 	u16 ext_addr;

 	/* set all fields to zero as default value */
 	memset(gpd, 0, sizeof(*gpd));

 	gpd->buffer = cpu_to_le32(lower_32_bits(req->dma));
 	ext_addr = GPD_EXT_BUF(upper_32_bits(req->dma));
 	gpd->buf_len = cpu_to_le16(req->length);
 	gpd->flag |= GPD_FLAGS_IOC;

 	/* get the next GPD */
 	enq = advance_enq_gpd(ring);
 	enq_dma = gpd_virt_to_dma(ring, enq);
 	dev_dbg(mep->mtu->dev, "TX-EP%d queue gpd=%p, enq=%p, qdma=%pad\n",
 		mep->epnum, gpd, enq, &enq_dma);

 	enq->flag &= ~GPD_FLAGS_HWO;
 	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
 	ext_addr |= GPD_EXT_NGP(upper_32_bits(enq_dma));
 	gpd->tx_ext_addr = cpu_to_le16(ext_addr);

 	if (req->zero)
 		gpd->ext_flag |= GPD_EXT_FLAG_ZLP;

 	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;
 	dma_addr_t enq_dma;
 	u16 ext_addr;

 	/* set all fields to zero as default value */
 	memset(gpd, 0, sizeof(*gpd));

 	gpd->buffer = cpu_to_le32(lower_32_bits(req->dma));
 	ext_addr = GPD_EXT_BUF(upper_32_bits(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);
 	enq_dma = gpd_virt_to_dma(ring, enq);
 	dev_dbg(mep->mtu->dev, "RX-EP%d queue gpd=%p, enq=%p, qdma=%pad\n",
 		mep->epnum, gpd, enq, &enq_dma);

 	enq->flag &= ~GPD_FLAGS_HWO;
 	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
 	ext_addr |= GPD_EXT_NGP(upper_32_bits(enq_dma));
 	gpd->rx_ext_addr = cpu_to_le16(ext_addr);
 	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 */
 		write_txq_start_addr(mbase, epnum, ring->dma);
 		mtu3_setbits(mbase, MU3D_EP_TXCR0(epnum), TX_DMAREQEN);
 		/* 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 {
 		write_rxq_start_addr(mbase, epnum, ring->dma);
 		mtu3_setbits(mbase, MU3D_EP_RXCR0(epnum), RX_DMAREQEN);
 		/* 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;
 	struct usb_request *req = NULL;
 	struct mtu3_request *mreq;
 	dma_addr_t cur_gpd_dma;
 	u32 txcsr = 0;
 	int ret;

 	mreq = next_request(mep);
 	if (mreq && mreq->request.length == 0)
 		req = &mreq->request;
 	else
 		return;

 	cur_gpd_dma = read_txq_cur_addr(mbase, epnum);
 	gpd_current = gpd_dma_to_virt(ring, cur_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__, req);

 	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->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;
 	struct usb_request *request = NULL;
 	struct mtu3_request *mreq;
 	dma_addr_t cur_gpd_dma;

 	/*transfer phy address got from QMU register to virtual address */
 	cur_gpd_dma = read_txq_cur_addr(mbase, epnum);
 	gpd_current = gpd_dma_to_virt(ring, cur_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;
 	struct usb_request *req = NULL;
 	struct mtu3_request *mreq;
 	dma_addr_t cur_gpd_dma;

 	cur_gpd_dma = read_rxq_cur_addr(mbase, epnum);
 	gpd_current = gpd_dma_to_virt(ring, cur_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);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* mtu3_qmu.c - Queue Management Unit driver for device controller
	*
	* Copyright (C) 2016 MediaTek Inc.
	*
	* Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
	*/

	/*
	* 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)
	#define GPD_EXT_NGP(x) (((x) & 0xf) << 4)
	#define GPD_EXT_BUF(x) (((x) & 0xf) << 0)

	#define HILO_GEN64(hi, lo) (((u64)(hi) << 32) + (lo))
	#define HILO_DMA(hi, lo) \
	((dma_addr_t)HILO_GEN64((le32_to_cpu(hi)), (le32_to_cpu(lo))))

	static dma_addr_t read_txq_cur_addr(void __iomem *mbase, u8 epnum)
	{
	u32 txcpr;
	u32 txhiar;

	txcpr = mtu3_readl(mbase, USB_QMU_TQCPR(epnum));
	txhiar = mtu3_readl(mbase, USB_QMU_TQHIAR(epnum));

	return HILO_DMA(QMU_CUR_GPD_ADDR_HI(txhiar), txcpr);
	}

	static dma_addr_t read_rxq_cur_addr(void __iomem *mbase, u8 epnum)
	{
	u32 rxcpr;
	u32 rxhiar;

	rxcpr = mtu3_readl(mbase, USB_QMU_RQCPR(epnum));
	rxhiar = mtu3_readl(mbase, USB_QMU_RQHIAR(epnum));

	return HILO_DMA(QMU_CUR_GPD_ADDR_HI(rxhiar), rxcpr);
	}

	static void write_txq_start_addr(void __iomem *mbase, u8 epnum, dma_addr_t dma)
	{
	u32 tqhiar;

	mtu3_writel(mbase, USB_QMU_TQSAR(epnum),
	cpu_to_le32(lower_32_bits(dma)));
	tqhiar = mtu3_readl(mbase, USB_QMU_TQHIAR(epnum));
	tqhiar &= ~QMU_START_ADDR_HI_MSK;
	tqhiar \|= QMU_START_ADDR_HI(upper_32_bits(dma));
	mtu3_writel(mbase, USB_QMU_TQHIAR(epnum), tqhiar);
	}

	static void write_rxq_start_addr(void __iomem *mbase, u8 epnum, dma_addr_t dma)
	{
	u32 rqhiar;

	mtu3_writel(mbase, USB_QMU_RQSAR(epnum),
	cpu_to_le32(lower_32_bits(dma)));
	rqhiar = mtu3_readl(mbase, USB_QMU_RQHIAR(epnum));
	rqhiar &= ~QMU_START_ADDR_HI_MSK;
	rqhiar \|= QMU_START_ADDR_HI(upper_32_bits(dma));
	mtu3_writel(mbase, USB_QMU_RQHIAR(epnum), rqhiar);
	}

	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));
	}

	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 */
	static 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;
	dma_addr_t enq_dma;
	u16 ext_addr;

	/* set all fields to zero as default value */
	memset(gpd, 0, sizeof(*gpd));

	gpd->buffer = cpu_to_le32(lower_32_bits(req->dma));
	ext_addr = GPD_EXT_BUF(upper_32_bits(req->dma));
	gpd->buf_len = cpu_to_le16(req->length);
	gpd->flag \|= GPD_FLAGS_IOC;

	/* get the next GPD */
	enq = advance_enq_gpd(ring);
	enq_dma = gpd_virt_to_dma(ring, enq);
	dev_dbg(mep->mtu->dev, "TX-EP%d queue gpd=%p, enq=%p, qdma=%pad\n",
	mep->epnum, gpd, enq, &enq_dma);

	enq->flag &= ~GPD_FLAGS_HWO;
	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
	ext_addr \|= GPD_EXT_NGP(upper_32_bits(enq_dma));
	gpd->tx_ext_addr = cpu_to_le16(ext_addr);

	if (req->zero)
	gpd->ext_flag \|= GPD_EXT_FLAG_ZLP;

	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;
	dma_addr_t enq_dma;
	u16 ext_addr;

	/* set all fields to zero as default value */
	memset(gpd, 0, sizeof(*gpd));

	gpd->buffer = cpu_to_le32(lower_32_bits(req->dma));
	ext_addr = GPD_EXT_BUF(upper_32_bits(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);
	enq_dma = gpd_virt_to_dma(ring, enq);
	dev_dbg(mep->mtu->dev, "RX-EP%d queue gpd=%p, enq=%p, qdma=%pad\n",
	mep->epnum, gpd, enq, &enq_dma);

	enq->flag &= ~GPD_FLAGS_HWO;
	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
	ext_addr \|= GPD_EXT_NGP(upper_32_bits(enq_dma));
	gpd->rx_ext_addr = cpu_to_le16(ext_addr);
	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 */
	write_txq_start_addr(mbase, epnum, ring->dma);
	mtu3_setbits(mbase, MU3D_EP_TXCR0(epnum), TX_DMAREQEN);
	/* 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 {
	write_rxq_start_addr(mbase, epnum, ring->dma);
	mtu3_setbits(mbase, MU3D_EP_RXCR0(epnum), RX_DMAREQEN);
	/* 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;
	struct usb_request *req = NULL;
	struct mtu3_request *mreq;
	dma_addr_t cur_gpd_dma;
	u32 txcsr = 0;
	int ret;

	mreq = next_request(mep);
	if (mreq && mreq->request.length == 0)
	req = &mreq->request;
	else
	return;

	cur_gpd_dma = read_txq_cur_addr(mbase, epnum);
	gpd_current = gpd_dma_to_virt(ring, cur_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__, req);

	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->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;
	struct usb_request *request = NULL;
	struct mtu3_request *mreq;
	dma_addr_t cur_gpd_dma;

	/transfer phy address got from QMU register to virtual address /
	cur_gpd_dma = read_txq_cur_addr(mbase, epnum);
	gpd_current = gpd_dma_to_virt(ring, cur_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;
	struct usb_request *req = NULL;
	struct mtu3_request *mreq;
	dma_addr_t cur_gpd_dma;

	cur_gpd_dma = read_rxq_cur_addr(mbase, epnum);
	gpd_current = gpd_dma_to_virt(ring, cur_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);
	}