From: Shun-Chih Yu <shun-chih...@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...@mediatek.com>
---
 drivers/dma/mediatek/Kconfig     |   12 +
 drivers/dma/mediatek/Makefile    |    1 +
 drivers/dma/mediatek/mtk-cqdma.c |  748 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 761 insertions(+)
 create mode 100644 drivers/dma/mediatek/mtk-cqdma.c

diff --git a/drivers/dma/mediatek/Kconfig b/drivers/dma/mediatek/Kconfig
index 27bac0b..4a1582d 100644
--- a/drivers/dma/mediatek/Kconfig
+++ b/drivers/dma/mediatek/Kconfig
@@ -11,3 +11,15 @@ 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
+       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..0009260
--- /dev/null
+++ b/drivers/dma/mediatek/mtk-cqdma.c
@@ -0,0 +1,748 @@
+// 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...@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/preempt.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_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
+ * @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
+ */
+struct mtk_cqdma_vdesc {
+       struct virt_dma_desc vd;
+       size_t len;
+       dma_addr_t dest;
+       dma_addr_t src;
+       struct dma_chan *ch;
+};
+
+/**
+ * struct mtk_cqdma_pchan - The struct holding info describing physical
+ *                         channel (PC)
+ * @active_vdesc:          Pointer to the CVD which is under hardware 
processing
+ * @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
+ * @lock:                  Lock protect agaisting multiple VCs access PC
+ */
+struct mtk_cqdma_pchan {
+       struct mtk_cqdma_vdesc *active_vdesc;
+       void __iomem *base;
+       u32 irq;
+       refcount_t refcnt;
+       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
+ */
+struct mtk_cqdma_vchan {
+       struct virt_dma_chan vc;
+       struct mtk_cqdma_pchan *pc;
+};
+
+/**
+ * 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_relaxed(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)
+{
+       u32 status = 0;
+
+       if (!in_task())
+               return readl_poll_timeout(pc->base + MTK_CQDMA_EN,
+                                         status,
+                                         !(status & MTK_CQDMA_EN_BIT),
+                                         MTK_CQDMA_USEC_POLL,
+                                         MTK_CQDMA_TIMEOUT_POLL);
+       else
+               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);
+}
+
+static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
+                           struct mtk_cqdma_vdesc *cvd)
+{
+       /* 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) < 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);
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+       mtk_dma_set(pc, MTK_CQDMA_SRC2, cvd->src >> MTK_CQDMA_ADDR2_SHFIT);
+#else
+       mtk_dma_set(pc, MTK_CQDMA_SRC2, 0);
+#endif
+
+       /* setup the destination */
+       mtk_dma_set(pc, MTK_CQDMA_DST, cvd->dest & MTK_CQDMA_ADDR_LIMIT);
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+       mtk_dma_set(pc, MTK_CQDMA_DST2, cvd->dest >> MTK_CQDMA_ADDR2_SHFIT);
+#else
+       mtk_dma_set(pc, MTK_CQDMA_DST2, 0);
+#endif
+
+       /* setup the length */
+       mtk_dma_set(pc, MTK_CQDMA_LEN1, (cvd->len < MTK_CQDMA_MAX_LEN) ?
+                   cvd->len : MTK_CQDMA_MAX_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;
+       struct mtk_cqdma_pchan *pc = cvc->pc;
+
+       lockdep_assert_held(&cvc->vc.lock);
+       lockdep_assert_held(&pc->lock);
+
+       vd = vchan_next_desc(&cvc->vc);
+
+       if (vd && !pc->active_vdesc) {
+               pc->active_vdesc = to_cqdma_vdesc(vd);
+               mtk_cqdma_start(pc, pc->active_vdesc);
+       }
+}
+
+/*
+ * 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)
+{
+       return (!cvc->pc->active_vdesc) ? false :
+              (cvc == to_cqdma_vchan(cvc->pc->active_vdesc->ch));
+}
+
+static void mtk_cqdma_complete_vdesc(struct mtk_cqdma_pchan *pc)
+{
+       struct mtk_cqdma_vchan *cvc;
+       struct mtk_cqdma_vdesc *cvd;
+       struct virt_dma_desc *vd;
+       size_t tlen;
+
+       cvd = pc->active_vdesc;
+       cvc = to_cqdma_vchan(cvd->ch);
+
+       tlen = (cvd->len < MTK_CQDMA_MAX_LEN) ? cvd->len : MTK_CQDMA_MAX_LEN;
+       cvd->len -= tlen;
+       cvd->src += tlen;
+       cvd->dest += tlen;
+
+       spin_lock(&cvc->vc.lock);
+
+       /* check whether the VD completed */
+       if (!cvd->len) {
+               /* delete VD from desc_issued */
+               list_del(&cvd->vd.node);
+
+               /* add the VD into list desc_completed */
+               vchan_cookie_complete(&cvd->vd);
+
+               /* get the next active VD */
+               vd = vchan_next_desc(&cvc->vc);
+               pc->active_vdesc = (!vd) ? NULL : to_cqdma_vdesc(vd);
+       }
+
+       /* start the next transaction */
+       if (pc->active_vdesc)
+               mtk_cqdma_start(pc, pc->active_vdesc);
+
+       spin_unlock(&cvc->vc.lock);
+}
+
+static irqreturn_t mtk_cqdma_irq(int irq, void *devid)
+{
+       struct mtk_cqdma_device *cqdma = devid;
+       irqreturn_t ret = IRQ_NONE;
+       u32 i;
+
+       /* clear interrupt flags for each PC */
+       for (i = 0; i < cqdma->dma_channels; ++i) {
+               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);
+
+                       mtk_cqdma_complete_vdesc(cqdma->pc[i]);
+
+                       ret = IRQ_HANDLED;
+               }
+               spin_unlock(&cqdma->pc[i]->lock);
+       }
+
+       return ret;
+}
+
+static enum dma_status mtk_cqdma_tx_status(struct dma_chan *c,
+                                          dma_cookie_t cookie,
+                                          struct dma_tx_state *txstate)
+{
+       return dma_cookie_status(c, cookie, txstate);
+}
+
+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 VC's lock for lock dependency in ISR */
+       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;
+
+       cvd = kzalloc(sizeof(*cvd), GFP_NOWAIT);
+       if (!cvd)
+               return NULL;
+
+       /* setup dma channel */
+       cvd->ch = c;
+
+       /* setup sourece, destination, and length */
+       cvd->len = len;
+       cvd->src = src;
+       cvd->dest = dest;
+
+       return vchan_tx_prep(to_virt_chan(c), &cvd->vd, flags);
+}
+
+static int mtk_cqdma_terminate_all(struct dma_chan *c)
+{
+       struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
+       struct virt_dma_chan *vc = to_virt_chan(c);
+       unsigned long pc_flags;
+       unsigned long vc_flags;
+       LIST_HEAD(head);
+
+       do {
+               /* 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);
+
+               /* wait for the VC to be inactive  */
+               if (mtk_cqdma_is_vchan_active(cvc)) {
+                       spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+                       spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+                       continue;
+               }
+
+               /* get VDs from lists */
+               vchan_get_all_descriptors(vc, &head);
+
+               /* free all the VDs */
+               vchan_dma_desc_free_list(vc, &head);
+
+               spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
+               spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
+
+               break;
+       } while (1);
+
+       vchan_synchronize(&cvc->vc);
+
+       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 minimum 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) < 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_dbg(&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_dbg(&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;
+
+               cqdma->pc[i]->active_vdesc = NULL;
+               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);
+       }
+
+       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);
+
+       dev_dbg(&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);
+       }
+
+       /* 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...@mediatek.com>");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5

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