[PATCH 2/2] dmaengine: mediatek: Add MediaTek Command-Queue DMA controller for MT6765 SoC

shun-chih.yu
2018-10-17T09:36:59Z

From: Shun-Chih Yu <shun-chih.yu@mediatek.com>

MediaTek Command-Queue DMA controller (CQDMA) on MT6765 SoC is dedicated
to memory-to-memory transfer through queue based descriptor management.

There are only 3 physical channels inside CQDMA, while the driver is
extended to support 32 virtual channels for multiple dma users to issue
dma requests onto the CQDMA simultaneously.

Signed-off-by: Shun-Chih Yu <shun-chih.yu@mediatek.com>
---
drivers/dma/mediatek/Kconfig | 13 +
drivers/dma/mediatek/Makefile | 1 +
drivers/dma/mediatek/mtk-cqdma.c | 943 ++++++++++++++++++++++++++++++++++++++
3 files changed, 957 insertions(+)
create mode 100644 drivers/dma/mediatek/mtk-cqdma.c

diff --git a/drivers/dma/mediatek/Kconfig b/drivers/dma/mediatek/Kconfig
index 27bac0b..680fc05 100644
--- a/drivers/dma/mediatek/Kconfig
+++ b/drivers/dma/mediatek/Kconfig
@@ -11,3 +11,16 @@ config MTK_HSDMA
This controller provides the channels which is dedicated to
memory-to-memory transfer to offload from CPU through ring-
based descriptor management.
+
+config MTK_CQDMA
+ tristate "MediaTek Command-Queue DMA controller support"
+ depends on ARCH_MEDIATEK || COMPILE_TEST
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ select ASYNC_TX_ENABLE_CHANNEL_SWITCH
+ help
+ Enable support for Command-Queue DMA controller on MediaTek
+ SoCs.
+
+ This controller provides the channels which is dedicated to
+ memory-to-memory transfer to offload from CPU.
diff --git a/drivers/dma/mediatek/Makefile b/drivers/dma/mediatek/Makefile
index 6e778f8..41bb381 100644
--- a/drivers/dma/mediatek/Makefile
+++ b/drivers/dma/mediatek/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o
+obj-$(CONFIG_MTK_CQDMA) += mtk-cqdma.o
diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
new file mode 100644
index 0000000..310ecc5
--- /dev/null
+++ b/drivers/dma/mediatek/mtk-cqdma.c
@@ -0,0 +1,943 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018-2019 MediaTek Inc.
+
+/*
+ * Driver for MediaTek Command-Queue DMA Controller
+ *
+ * Author: Shun-Chih Yu <shun-chih.yu@mediatek.com>
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+
+#include "../virt-dma.h"
+
+#define MTK_CQDMA_USEC_POLL 10
+#define MTK_CQDMA_TIMEOUT_POLL 1000
+#define MTK_CQDMA_DMA_BUSWIDTHS BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
+#define MTK_CQDMA_ALIGN_SIZE 1
+
+/* The default number of virtual channel */
+#define MTK_CQDMA_NR_VCHANS 32
+
+/* The default number of physical channel */
+#define MTK_CQDMA_NR_PCHANS 3
+
+/* Registers for underlying dma manipulation */
+#define MTK_CQDMA_INT_FLAG 0x0
+#define MTK_CQDMA_INT_EN 0x4
+#define MTK_CQDMA_EN 0x8
+#define MTK_CQDMA_RESET 0xc
+#define MTK_CQDMA_FLUSH 0x14
+#define MTK_CQDMA_SRC 0x1c
+#define MTK_CQDMA_DST 0x20
+#define MTK_CQDMA_LEN1 0x24
+#define MTK_CQDMA_LEN2 0x28
+#define MTK_CQDMA_SRC2 0x60
+#define MTK_CQDMA_DST2 0x64
+
+/* Registers setting */
+#define MTK_CQDMA_EN_BIT BIT(0)
+#define MTK_CQDMA_INT_FLAG_BIT BIT(0)
+#define MTK_CQDMA_INT_EN_BIT BIT(0)
+#define MTK_CQDMA_FLUSH_BIT BIT(0)
+
+#define MTK_CQDMA_WARM_RST_BIT BIT(0)
+#define MTK_CQDMA_HARD_RST_BIT BIT(1)
+
+#define MTK_CQDMA_MAX_LEN GENMASK(27, 0)
+#define MTK_CQDMA_ADDR_LIMIT GENMASK(31, 0)
+#define MTK_CQDMA_ADDR2_SHFIT (32)
+
+/**
+ * struct mtk_cqdma_vdesc - The struct holding info describing virtual
+ * descriptor (CVD)
+ * @vd: An instance for struct virt_dma_desc
+ * @len: The total data size device wants to move
+ * @residue: The remaining data size device will move
+ * @dest: The destination address device wants to move to
+ * @src: The source address device wants to move from
+ * @ch: The pointer to the corresponding dma channel
+ * @node: The lise_head struct to build link-list for VDs
+ * @parent: The pointer to the parent CVD
+ */
+struct mtk_cqdma_vdesc {
+ struct virt_dma_desc vd;
+ size_t len;
+ size_t residue;
+ dma_addr_t dest;
+ dma_addr_t src;
+ struct dma_chan *ch;
+
+ struct list_head node;
+ struct mtk_cqdma_vdesc *parent;
+};
+
+/**
+ * struct mtk_cqdma_pchan - The struct holding info describing physical
+ * channel (PC)
+ * @queue: Queue for the PDs issued to this PC
+ * @base: The mapped register I/O base of this PC
+ * @irq: The IRQ that this PC are using
+ * @refcnt: Track how many VCs are using this PC
+ * @tasklet: Tasklet for this PC
+ * @lock: Lock protect agaisting multiple VCs access PC
+ */
+struct mtk_cqdma_pchan {
+ struct list_head queue;
+ void __iomem *base;
+ u32 irq;
+
+ refcount_t refcnt;
+
+ struct tasklet_struct tasklet;
+
+ /* lock to protect PC */
+ spinlock_t lock;
+};
+
+/**
+ * struct mtk_cqdma_vchan - The struct holding info describing virtual
+ * channel (VC)
+ * @vc: An instance for struct virt_dma_chan
+ * @pc: The pointer to the underlying PC
+ * @issue_completion: The wait for all issued descriptors completited
+ * @issue_synchronize: Bool indicating channel synchronization starts
+ */
+struct mtk_cqdma_vchan {
+ struct virt_dma_chan vc;
+ struct mtk_cqdma_pchan *pc;
+ struct completion issue_completion;
+ bool issue_synchronize;
+};
+
+/**
+ * struct mtk_cqdma_device - The struct holding info describing CQDMA
+ * device
+ * @ddev: An instance for struct dma_device
+ * @clk: The clock that device internal is using
+ * @dma_requests: The number of VCs the device supports to
+ * @dma_channels: The number of PCs the device supports to
+ * @vc: The pointer to all available VCs
+ * @pc: The pointer to all the underlying PCs
+ */
+struct mtk_cqdma_device {
+ struct dma_device ddev;
+ struct clk *clk;
+
+ u32 dma_requests;
+ u32 dma_channels;
+ struct mtk_cqdma_vchan *vc;
+ struct mtk_cqdma_pchan **pc;
+};
+
+static struct mtk_cqdma_device *to_cqdma_dev(struct dma_chan *chan)
+{
+ return container_of(chan->device, struct mtk_cqdma_device, ddev);
+}
+
+static struct mtk_cqdma_vchan *to_cqdma_vchan(struct dma_chan *chan)
+{
+ return container_of(chan, struct mtk_cqdma_vchan, vc.chan);
+}
+
+static struct mtk_cqdma_vdesc *to_cqdma_vdesc(struct virt_dma_desc *vd)
+{
+ return container_of(vd, struct mtk_cqdma_vdesc, vd);
+}
+
+static struct device *cqdma2dev(struct mtk_cqdma_device *cqdma)
+{
+ return cqdma->ddev.dev;
+}
+
+static u32 mtk_dma_read(struct mtk_cqdma_pchan *pc, u32 reg)
+{
+ return readl(pc->base + reg);
+}
+
+static void mtk_dma_write(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+ writel_relaxed(val, pc->base + reg);
+}
+
+static void mtk_dma_rmw(struct mtk_cqdma_pchan *pc, u32 reg,
+ u32 mask, u32 set)
+{
+ u32 val;
+
+ val = mtk_dma_read(pc, reg);
+ val &= ~mask;
+ val |= set;
+ mtk_dma_write(pc, reg, val);
+}
+
+static void mtk_dma_set(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+ mtk_dma_rmw(pc, reg, 0, val);
+}
+
+static void mtk_dma_clr(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
+{
+ mtk_dma_rmw(pc, reg, val, 0);
+}
+
+static void mtk_cqdma_vdesc_free(struct virt_dma_desc *vd)
+{
+ kfree(to_cqdma_vdesc(vd));
+}
+
+static int mtk_cqdma_poll_engine_done(struct mtk_cqdma_pchan *pc, bool atomic)
+{
+ u32 status = 0;
+
+ if (!atomic)
+ return readl_poll_timeout(pc->base + MTK_CQDMA_EN,
+ status,
+ !(status & MTK_CQDMA_EN_BIT),
+ MTK_CQDMA_USEC_POLL,
+ MTK_CQDMA_TIMEOUT_POLL);
+
+ return readl_poll_timeout_atomic(pc->base + MTK_CQDMA_EN,
+ status,
+ !(status & MTK_CQDMA_EN_BIT),
+ MTK_CQDMA_USEC_POLL,
+ MTK_CQDMA_TIMEOUT_POLL);
+}
+
+static int mtk_cqdma_hard_reset(struct mtk_cqdma_pchan *pc)
+{
+ mtk_dma_set(pc, MTK_CQDMA_RESET, MTK_CQDMA_HARD_RST_BIT);
+ mtk_dma_clr(pc, MTK_CQDMA_RESET, MTK_CQDMA_HARD_RST_BIT);
+
+ return mtk_cqdma_poll_engine_done(pc, false);
+}
+
+static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
+ struct mtk_cqdma_vdesc *cvd)
+{
+ /* wait for the previous transaction done */
+ if (mtk_cqdma_poll_engine_done(pc, true) < 0)
+ dev_err(cqdma2dev(to_cqdma_dev(cvd->ch)), "cqdma wait transaction timeout\n");
+
+ /* warm reset the dma engine for the new transaction */
+ mtk_dma_set(pc, MTK_CQDMA_RESET, MTK_CQDMA_WARM_RST_BIT);
+ if (mtk_cqdma_poll_engine_done(pc, true) < 0)
+ dev_err(cqdma2dev(to_cqdma_dev(cvd->ch)), "cqdma warm reset timeout\n");
+
+ /* setup the source */
+ mtk_dma_set(pc, MTK_CQDMA_SRC, cvd->src & MTK_CQDMA_ADDR_LIMIT);
+ mtk_dma_set(pc, MTK_CQDMA_SRC2, cvd->src >> MTK_CQDMA_ADDR2_SHFIT);
+
+ /* setup the destination */
+ mtk_dma_set(pc, MTK_CQDMA_DST, cvd->dest & MTK_CQDMA_ADDR_LIMIT);
+ mtk_dma_set(pc, MTK_CQDMA_DST2, cvd->dest >> MTK_CQDMA_ADDR2_SHFIT);
+
+ /* setup the length */
+ mtk_dma_set(pc, MTK_CQDMA_LEN1, cvd->len);
+
+ /* start dma engine */
+ mtk_dma_set(pc, MTK_CQDMA_EN, MTK_CQDMA_EN_BIT);
+}
+
+static void mtk_cqdma_issue_vchan_pending(struct mtk_cqdma_vchan *cvc)
+{
+ struct virt_dma_desc *vd, *vd2;
+ struct mtk_cqdma_pchan *pc = cvc->pc;
+ struct mtk_cqdma_vdesc *cvd;
+ bool trigger_engine = false;
+
+ lockdep_assert_held(&cvc->vc.lock);
+ lockdep_assert_held(&pc->lock);
+
+ list_for_each_entry_safe(vd, vd2, &cvc->vc.desc_issued, node) {
+ /* need to trigger dma engine if PC's queue is empty */
+ if (list_empty(&pc->queue))
+ trigger_engine = true;
+
+ cvd = to_cqdma_vdesc(vd);
+
+ /* add VD into PC's queue */
+ list_add_tail(&cvd->node, &pc->queue);
+
+ /* start the dma engine */
+ if (trigger_engine)
+ mtk_cqdma_start(pc, cvd);
+
+ /* remove VD from list desc_issued */
+ list_del(&vd->node);
+ }
+}
+
+/*
+ * return true if this VC is active,
+ * meaning that there are VDs under processing by the PC
+ */
+static bool mtk_cqdma_is_vchan_active(struct mtk_cqdma_vchan *cvc)
+{
+ struct mtk_cqdma_vdesc *cvd;
+
+ list_for_each_entry(cvd, &cvc->pc->queue, node)
+ if (cvc == to_cqdma_vchan(cvd->ch))
+ return true;
+
+ return false;
+}
+
+/*
+ * return the pointer of the CVD that is just consumed by the PC
+ */
+static struct mtk_cqdma_vdesc
+*mtk_cqdma_consume_work_queue(struct mtk_cqdma_pchan *pc)
+{
+ struct mtk_cqdma_vchan *cvc;
+ struct mtk_cqdma_vdesc *cvd, *ret = NULL;
+
+ /* consume a CVD from PC's queue */
+ cvd = list_first_entry_or_null(&pc->queue,
+ struct mtk_cqdma_vdesc, node);
+ if (unlikely(!cvd || !cvd->parent))
+ return NULL;
+
+ cvc = to_cqdma_vchan(cvd->ch);
+ ret = cvd;
+
+ /* update residue of the parent CVD */
+ cvd->parent->residue -= cvd->len;
+
+ /* delete CVD from PC's queue */
+ list_del(&cvd->node);
+
+ spin_lock(&cvc->vc.lock);
+
+ /* check whether all the child CVDs completed */
+ if (!cvd->parent->residue) {
+ /* add the parent VD into list desc_completed */
+ vchan_cookie_complete(&cvd->parent->vd);
+
+ /* setup completion if this VC is under synchronization */
+ if (cvc->issue_synchronize && !mtk_cqdma_is_vchan_active(cvc)) {
+ complete(&cvc->issue_completion);
+ cvc->issue_synchronize = false;
+ }
+ }
+
+ spin_unlock(&cvc->vc.lock);
+
+ /* start transaction for next CVD in the queue */
+ cvd = list_first_entry_or_null(&pc->queue,
+ struct mtk_cqdma_vdesc, node);
+ if (cvd)
+ mtk_cqdma_start(pc, cvd);
+
+ return ret;
+}
+
+static void mtk_cqdma_tasklet_cb(unsigned long data)
+{
+ struct mtk_cqdma_pchan *pc = (struct mtk_cqdma_pchan *)data;
+ struct mtk_cqdma_vdesc *cvd = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pc->lock, flags);
+ /* consume the queue */
+ cvd = mtk_cqdma_consume_work_queue(pc);
+ spin_unlock_irqrestore(&pc->lock, flags);
+
+ /* submit the next CVD */
+ if (cvd) {
+ dma_run_dependencies(&cvd->vd.tx);
+
+ /*
+ * free child CVD after completion.
+ * the parent CVD would be freeed with desc_free by user.
+ */
+ if (cvd->parent != cvd)
+ kfree(cvd);
+ }
+
+ /* re-enable interrupt before leaving tasklet */
+ enable_irq(pc->irq);
+}
+
+static irqreturn_t mtk_cqdma_irq(int irq, void *devid)
+{
+ struct mtk_cqdma_device *cqdma = devid;
+ irqreturn_t ret = IRQ_NONE;
+ bool schedule_tasklet = false;
+ u32 i;
+
+ /* clear interrupt flags for each PC */
+ for (i = 0; i < cqdma->dma_channels; ++i, schedule_tasklet = false) {
+ spin_lock(&cqdma->pc[i]->lock);
+ if (mtk_dma_read(cqdma->pc[i],
+ MTK_CQDMA_INT_FLAG) & MTK_CQDMA_INT_FLAG_BIT) {
+ /* clear interrupt */
+ mtk_dma_clr(cqdma->pc[i], MTK_CQDMA_INT_FLAG,
+ MTK_CQDMA_INT_FLAG_BIT);
+
+ schedule_tasklet = true;
+ ret = IRQ_HANDLED;
+ }
+ spin_unlock(&cqdma->pc[i]->lock);
+
+ if (schedule_tasklet) {
+ /* disable interrupt */
+ disable_irq_nosync(cqdma->pc[i]->irq);
+
+ /* schedule the tasklet to handle the transactions */
+ tasklet_schedule(&cqdma->pc[i]->tasklet);
+ }
+ }
+
+ return ret;
+}
+
+static struct virt_dma_desc *mtk_cqdma_find_active_desc(struct dma_chan *c,
+ dma_cookie_t cookie)
+{
+ struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+ struct virt_dma_desc *vd;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cvc->pc->lock, flags);
+ list_for_each_entry(vd, &cvc->pc->queue, node)
+ if (vd->tx.cookie == cookie) {
+ spin_unlock_irqrestore(&cvc->pc->lock, flags);
+ return vd;
+ }
+ spin_unlock_irqrestore(&cvc->pc->lock, flags);
+
+ list_for_each_entry(vd, &cvc->vc.desc_issued, node)
+ if (vd->tx.cookie == cookie)
+ return vd;
+
+ return NULL;
+}
+
+static enum dma_status mtk_cqdma_tx_status(struct dma_chan *c,
+ dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+ struct mtk_cqdma_vdesc *cvd;
+ struct virt_dma_desc *vd;
+ enum dma_status ret;
+ unsigned long flags;
+ size_t bytes = 0;
+
+ ret = dma_cookie_status(c, cookie, txstate);
+ if (ret == DMA_COMPLETE || !txstate)
+ return ret;
+
+ spin_lock_irqsave(&cvc->vc.lock, flags);
+ vd = mtk_cqdma_find_active_desc(c, cookie);
+ spin_unlock_irqrestore(&cvc->vc.lock, flags);
+
+ if (vd) {
+ cvd = to_cqdma_vdesc(vd);
+ bytes = cvd->residue;
+ }
+
+ dma_set_residue(txstate, bytes);
+
+ return ret;
+}
+
+static void mtk_cqdma_issue_pending(struct dma_chan *c)
+{
+ struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+ unsigned long pc_flags;
+ unsigned long vc_flags;
+
+ /* acquire PC's lock before VS's lock for lock dependency in tasklet */
+ spin_lock_irqsave(&cvc->pc->lock, pc_flags);
+ spin_lock_irqsave(&cvc->vc.lock, vc_flags);
+
+ if (vchan_issue_pending(&cvc->vc))
+ mtk_cqdma_issue_vchan_pending(cvc);
+
+ spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+ spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+}
+
+static struct dma_async_tx_descriptor *
+mtk_cqdma_prep_dma_memcpy(struct dma_chan *c, dma_addr_t dest,
+ dma_addr_t src, size_t len, unsigned long flags)
+{
+ struct mtk_cqdma_vdesc **cvd;
+ struct dma_async_tx_descriptor *tx = NULL, *prev_tx = NULL;
+ size_t i, tlen, nr_vd;
+
+ /*
+ * In the case that trsanction length is larger than the
+ * DMA engine supports, a single memcpy transaction needs
+ * to be separated into several DMA transactions.
+ * Each DMA transaction would be described by a CVD,
+ * and the first one is referred as the parent CVD,
+ * while the others are child CVDs.
+ * The parent CVD's tx descriptor is the only tx descriptor
+ * returned to the DMA user, and it should not be completed
+ * until all the child CVDs completed.
+ */
+ nr_vd = DIV_ROUND_UP(len, MTK_CQDMA_MAX_LEN);
+ cvd = kcalloc(nr_vd, sizeof(*cvd), GFP_NOWAIT);
+ if (!cvd)
+ return NULL;
+
+ for (i = 0; i < nr_vd; ++i) {
+ cvd[i] = kzalloc(sizeof(*cvd[i]), GFP_NOWAIT);
+ if (!cvd[i]) {
+ for (; i > 0; --i)
+ kfree(cvd[i - 1]);
+ return NULL;
+ }
+
+ /* setup dma channel */
+ cvd[i]->ch = c;
+
+ /* setup sourece, destination, and length */
+ tlen = (len > MTK_CQDMA_MAX_LEN) ? MTK_CQDMA_MAX_LEN : len;
+ cvd[i]->len = tlen;
+ cvd[i]->src = src;
+ cvd[i]->dest = dest;
+
+ /* setup tx descriptor */
+ tx = vchan_tx_prep(to_virt_chan(c), &cvd[i]->vd, flags);
+ tx->next = NULL;
+
+ if (!i) {
+ cvd[0]->residue = len;
+ } else {
+ prev_tx->next = tx;
+ cvd[i]->residue = tlen;
+ }
+
+ cvd[i]->parent = cvd[0];
+
+ /* update the src, dest, len, prev_tx for the next CVD */
+ src += tlen;
+ dest += tlen;
+ len -= tlen;
+ prev_tx = tx;
+ }
+
+ return &cvd[0]->vd.tx;
+}
+
+static void mtk_cqdma_free_inactive_desc(struct dma_chan *c)
+{
+ struct virt_dma_chan *vc = to_virt_chan(c);
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ /*
+ * set desc_allocated, desc_submitted,
+ * and desc_issued as the candicates to be freed
+ */
+ spin_lock_irqsave(&vc->lock, flags);
+ list_splice_tail_init(&vc->desc_allocated, &head);
+ list_splice_tail_init(&vc->desc_submitted, &head);
+ list_splice_tail_init(&vc->desc_issued, &head);
+ spin_unlock_irqrestore(&vc->lock, flags);
+
+ /* free descriptor lists */
+ vchan_dma_desc_free_list(vc, &head);
+}
+
+static void mtk_cqdma_free_active_desc(struct dma_chan *c)
+{
+ struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+ bool sync_needed = false;
+ unsigned long pc_flags;
+ unsigned long vc_flags;
+
+ /* acquire PC's lock first due to lock dependency in dma ISR */
+ spin_lock_irqsave(&cvc->pc->lock, pc_flags);
+ spin_lock_irqsave(&cvc->vc.lock, vc_flags);
+
+ /* synchronization is required if this VC is active */
+ if (mtk_cqdma_is_vchan_active(cvc)) {
+ cvc->issue_synchronize = true;
+ sync_needed = true;
+ }
+
+ spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+ spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+
+ /* waiting for the completion of this VC */
+ if (sync_needed)
+ wait_for_completion(&cvc->issue_completion);
+
+ /* free all descriptors in list desc_completed */
+ vchan_synchronize(&cvc->vc);
+
+ WARN_ONCE(!list_empty(&cvc->vc.desc_completed),
+ "Desc pending still in list desc_completed\n");
+}
+
+static int mtk_cqdma_terminate_all(struct dma_chan *c)
+{
+ /* free descriptors not processed yet by hardware */
+ mtk_cqdma_free_inactive_desc(c);
+
+ /* free descriptors being processed by hardware */
+ mtk_cqdma_free_active_desc(c);
+
+ return 0;
+}
+
+static int mtk_cqdma_alloc_chan_resources(struct dma_chan *c)
+{
+ struct mtk_cqdma_device *cqdma = to_cqdma_dev(c);
+ struct mtk_cqdma_vchan *vc = to_cqdma_vchan(c);
+ struct mtk_cqdma_pchan *pc = NULL;
+ u32 i, min_refcnt = U32_MAX, refcnt;
+ unsigned long flags;
+
+ /* allocate PC with the minimun refcount */
+ for (i = 0; i < cqdma->dma_channels; ++i) {
+ refcnt = refcount_read(&cqdma->pc[i]->refcnt);
+ if (refcnt < min_refcnt) {
+ pc = cqdma->pc[i];
+ min_refcnt = refcnt;
+ }
+ }
+
+ if (!pc)
+ return -ENOSPC;
+
+ spin_lock_irqsave(&pc->lock, flags);
+
+ if (!refcount_read(&pc->refcnt)) {
+ /* allocate PC when the refcount is zero */
+ mtk_cqdma_hard_reset(pc);
+
+ /* enable interrupt for this PC */
+ mtk_dma_set(pc, MTK_CQDMA_INT_EN, MTK_CQDMA_INT_EN_BIT);
+
+ /*
+ * refcount_inc would complain increment on 0; use-after-free.
+ * Thus, we need to explicitly set it as 1 initially.
+ */
+ refcount_set(&pc->refcnt, 1);
+ } else {
+ refcount_inc(&pc->refcnt);
+ }
+
+ spin_unlock_irqrestore(&pc->lock, flags);
+
+ vc->pc = pc;
+
+ return 0;
+}
+
+static void mtk_cqdma_free_chan_resources(struct dma_chan *c)
+{
+ struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+ unsigned long flags;
+
+ /* free all descriptors in all lists on the VC */
+ mtk_cqdma_terminate_all(c);
+
+ spin_lock_irqsave(&cvc->pc->lock, flags);
+
+ /* PC is not freed until there is no VC mapped to it */
+ if (refcount_dec_and_test(&cvc->pc->refcnt)) {
+ /* start the flush operation and stop the engine */
+ mtk_dma_set(cvc->pc, MTK_CQDMA_FLUSH, MTK_CQDMA_FLUSH_BIT);
+
+ /* wait for the completion of flush operation */
+ if (mtk_cqdma_poll_engine_done(cvc->pc, false) < 0)
+ dev_err(cqdma2dev(to_cqdma_dev(c)), "cqdma flush timeout\n");
+
+ /* clear the flush bit and interrupt flag */
+ mtk_dma_clr(cvc->pc, MTK_CQDMA_FLUSH, MTK_CQDMA_FLUSH_BIT);
+ mtk_dma_clr(cvc->pc, MTK_CQDMA_INT_FLAG,
+ MTK_CQDMA_INT_FLAG_BIT);
+
+ /* disable interrupt for this PC */
+ mtk_dma_clr(cvc->pc, MTK_CQDMA_INT_EN, MTK_CQDMA_INT_EN_BIT);
+ }
+
+ spin_unlock_irqrestore(&cvc->pc->lock, flags);
+}
+
+static int mtk_cqdma_hw_init(struct mtk_cqdma_device *cqdma)
+{
+ unsigned long flags;
+ int err;
+ u32 i;
+
+ pm_runtime_enable(cqdma2dev(cqdma));
+ pm_runtime_get_sync(cqdma2dev(cqdma));
+
+ err = clk_prepare_enable(cqdma->clk);
+
+ if (err) {
+ pm_runtime_put_sync(cqdma2dev(cqdma));
+ pm_runtime_disable(cqdma2dev(cqdma));
+ return err;
+ }
+
+ /* reset all PCs */
+ for (i = 0; i < cqdma->dma_channels; ++i) {
+ spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+ if (mtk_cqdma_hard_reset(cqdma->pc[i]) < 0) {
+ dev_err(cqdma2dev(cqdma), "cqdma hard reset timeout\n");
+ spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+
+ clk_disable_unprepare(cqdma->clk);
+ pm_runtime_put_sync(cqdma2dev(cqdma));
+ pm_runtime_disable(cqdma2dev(cqdma));
+ return -EINVAL;
+ }
+ spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+ }
+
+ return 0;
+}
+
+static void mtk_cqdma_hw_deinit(struct mtk_cqdma_device *cqdma)
+{
+ unsigned long flags;
+ u32 i;
+
+ /* reset all PCs */
+ for (i = 0; i < cqdma->dma_channels; ++i) {
+ spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+ if (mtk_cqdma_hard_reset(cqdma->pc[i]) < 0)
+ dev_err(cqdma2dev(cqdma), "cqdma hard reset timeout\n");
+ spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+ }
+
+ clk_disable_unprepare(cqdma->clk);
+
+ pm_runtime_put_sync(cqdma2dev(cqdma));
+ pm_runtime_disable(cqdma2dev(cqdma));
+}
+
+static const struct of_device_id mtk_cqdma_match[] = {
+ { .compatible = "mediatek,mt6765-cqdma" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_cqdma_match);
+
+static int mtk_cqdma_probe(struct platform_device *pdev)
+{
+ struct mtk_cqdma_device *cqdma;
+ struct mtk_cqdma_vchan *vc;
+ struct dma_device *dd;
+ struct resource *res;
+ int err;
+ u32 i;
+
+ cqdma = devm_kzalloc(&pdev->dev, sizeof(*cqdma), GFP_KERNEL);
+ if (!cqdma)
+ return -ENOMEM;
+
+ dd = &cqdma->ddev;
+
+ cqdma->clk = devm_clk_get(&pdev->dev, "cqdma");
+ if (IS_ERR(cqdma->clk)) {
+ dev_err(&pdev->dev, "No clock for %s\n",
+ dev_name(&pdev->dev));
+ return PTR_ERR(cqdma->clk);
+ }
+
+ dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+
+ dd->copy_align = MTK_CQDMA_ALIGN_SIZE;
+ dd->device_alloc_chan_resources = mtk_cqdma_alloc_chan_resources;
+ dd->device_free_chan_resources = mtk_cqdma_free_chan_resources;
+ dd->device_tx_status = mtk_cqdma_tx_status;
+ dd->device_issue_pending = mtk_cqdma_issue_pending;
+ dd->device_prep_dma_memcpy = mtk_cqdma_prep_dma_memcpy;
+ dd->device_terminate_all = mtk_cqdma_terminate_all;
+ dd->src_addr_widths = MTK_CQDMA_DMA_BUSWIDTHS;
+ dd->dst_addr_widths = MTK_CQDMA_DMA_BUSWIDTHS;
+ dd->directions = BIT(DMA_MEM_TO_MEM);
+ dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+ dd->dev = &pdev->dev;
+ INIT_LIST_HEAD(&dd->channels);
+
+ if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+ "dma-requests",
+ &cqdma->dma_requests)) {
+ dev_info(&pdev->dev,
+ "Using %u as missing dma-requests property\n",
+ MTK_CQDMA_NR_VCHANS);
+
+ cqdma->dma_requests = MTK_CQDMA_NR_VCHANS;
+ }
+
+ if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
+ "dma-channels",
+ &cqdma->dma_channels)) {
+ dev_info(&pdev->dev,
+ "Using %u as missing dma-channels property\n",
+ MTK_CQDMA_NR_PCHANS);
+
+ cqdma->dma_channels = MTK_CQDMA_NR_PCHANS;
+ }
+
+ cqdma->pc = devm_kcalloc(&pdev->dev, cqdma->dma_channels,
+ sizeof(*cqdma->pc), GFP_KERNEL);
+ if (!cqdma->pc)
+ return -ENOMEM;
+
+ /* initialization for PCs */
+ for (i = 0; i < cqdma->dma_channels; ++i) {
+ cqdma->pc[i] = devm_kcalloc(&pdev->dev, 1,
+ sizeof(**cqdma->pc), GFP_KERNEL);
+ if (!cqdma->pc[i])
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&cqdma->pc[i]->queue);
+ spin_lock_init(&cqdma->pc[i]->lock);
+ refcount_set(&cqdma->pc[i]->refcnt, 0);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+ if (!res) {
+ dev_err(&pdev->dev, "No mem resource for %s\n",
+ dev_name(&pdev->dev));
+ return -EINVAL;
+ }
+
+ cqdma->pc[i]->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(cqdma->pc[i]->base))
+ return PTR_ERR(cqdma->pc[i]->base);
+
+ /* allocate IRQ resource */
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+ if (!res) {
+ dev_err(&pdev->dev, "No irq resource for %s\n",
+ dev_name(&pdev->dev));
+ return -EINVAL;
+ }
+ cqdma->pc[i]->irq = res->start;
+
+ err = devm_request_irq(&pdev->dev, cqdma->pc[i]->irq,
+ mtk_cqdma_irq, 0, dev_name(&pdev->dev),
+ cqdma);
+ if (err) {
+ dev_err(&pdev->dev,
+ "request_irq failed with err %d\n", err);
+ return -EINVAL;
+ }
+ }
+
+ /* allocate resource for VCs */
+ cqdma->vc = devm_kcalloc(&pdev->dev, cqdma->dma_requests,
+ sizeof(*cqdma->vc), GFP_KERNEL);
+ if (!cqdma->vc)
+ return -ENOMEM;
+
+ for (i = 0; i < cqdma->dma_requests; i++) {
+ vc = &cqdma->vc[i];
+ vc->vc.desc_free = mtk_cqdma_vdesc_free;
+ vchan_init(&vc->vc, dd);
+ init_completion(&vc->issue_completion);
+ }
+
+ err = dma_async_device_register(dd);
+ if (err)
+ return err;
+
+ err = of_dma_controller_register(pdev->dev.of_node,
+ of_dma_xlate_by_chan_id, cqdma);
+ if (err) {
+ dev_err(&pdev->dev,
+ "MediaTek CQDMA OF registration failed %d\n", err);
+ goto err_unregister;
+ }
+
+ err = mtk_cqdma_hw_init(cqdma);
+ if (err) {
+ dev_err(&pdev->dev,
+ "MediaTek CQDMA HW initialization failed %d\n", err);
+ goto err_unregister;
+ }
+
+ platform_set_drvdata(pdev, cqdma);
+
+ /* initialize tasklet for each PC */
+ for (i = 0; i < cqdma->dma_channels; ++i)
+ tasklet_init(&cqdma->pc[i]->tasklet, mtk_cqdma_tasklet_cb,
+ (unsigned long)cqdma->pc[i]);
+
+ dev_info(&pdev->dev, "MediaTek CQDMA driver registered\n");
+
+ return 0;
+
+err_unregister:
+ dma_async_device_unregister(dd);
+
+ return err;
+}
+
+static int mtk_cqdma_remove(struct platform_device *pdev)
+{
+ struct mtk_cqdma_device *cqdma = platform_get_drvdata(pdev);
+ struct mtk_cqdma_vchan *vc;
+ unsigned long flags;
+ int i;
+
+ /* kill VC task */
+ for (i = 0; i < cqdma->dma_requests; i++) {
+ vc = &cqdma->vc[i];
+
+ list_del(&vc->vc.chan.device_node);
+ tasklet_kill(&vc->vc.task);
+ }
+
+ /* disable interrupt */
+ for (i = 0; i < cqdma->dma_channels; i++) {
+ spin_lock_irqsave(&cqdma->pc[i]->lock, flags);
+ mtk_dma_clr(cqdma->pc[i], MTK_CQDMA_INT_EN,
+ MTK_CQDMA_INT_EN_BIT);
+ spin_unlock_irqrestore(&cqdma->pc[i]->lock, flags);
+
+ /* Waits for any pending IRQ handlers to complete */
+ synchronize_irq(cqdma->pc[i]->irq);
+
+ tasklet_kill(&cqdma->pc[i]->tasklet);
+ }
+
+ /* disable hardware */
+ mtk_cqdma_hw_deinit(cqdma);
+
+ dma_async_device_unregister(&cqdma->ddev);
+ of_dma_controller_free(pdev->dev.of_node);
+
+ return 0;
+}
+
+static struct platform_driver mtk_cqdma_driver = {
+ .probe = mtk_cqdma_probe,
+ .remove = mtk_cqdma_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = mtk_cqdma_match,
+ },
+};
+module_platform_driver(mtk_cqdma_driver);
+
+MODULE_DESCRIPTION("MediaTek CQDMA Controller Driver");
+MODULE_AUTHOR("Shun-Chih Yu <shun-chih.yu@mediatek.com>");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5