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Date: Thu, 24 Jan 2019 20:19:39 -0800
From: Sean Wang <sean.wang@...nel.org>
To: shun-chih.yu@...iatek.com
Cc: Sean Wang <sean.wang@...iatek.com>, Vinod Koul <vkoul@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Dan Williams <dan.j.williams@...el.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
srv_wsdupstream@...iatek.com, linux-mediatek@...ts.infradead.org,
dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/2] dmaengine: mediatek-cqdma: remove redundant queue structure
On Thu, Jan 24, 2019 at 2:46 AM <shun-chih.yu@...iatek.com> wrote:
>
> From: Shun-Chih Yu <shun-chih.yu@...iatek.com>
>
> This patch introduces active_vdec to indicate the virtual descriptor
> under processing by the CQDMA dmaengine, and simplify the control logic
> by removing redundant queue structure, tasklets, and completion
> management.
>
> Also, wrong residue assignment in mtk_cqdma_tx_status and typos are
> fixed.
overall changes are good and let code become clear, but it's better to
do one thing at a patch instead of mixing all stuff together.
>
> Signed-off-by: Shun-Chih Yu <shun-chih.yu@...iatek.com>
> ---
> drivers/dma/mediatek/mtk-cqdma.c | 399 ++++++++++----------------------------
> 1 file changed, 98 insertions(+), 301 deletions(-)
>
> diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
> index 131f397..387781b 100644
> --- a/drivers/dma/mediatek/mtk-cqdma.c
> +++ b/drivers/dma/mediatek/mtk-cqdma.c
> @@ -22,6 +22,7 @@
> #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>
>
> @@ -47,7 +48,6 @@
> #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
>
> @@ -69,45 +69,32 @@
> * 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
> + * @active_vdesc: The pointer to the CVD which is under 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
> - * @tasklet: Tasklet for this PC
> * @lock: Lock protect agaisting multiple VCs access PC
> */
> struct mtk_cqdma_pchan {
> - struct list_head queue;
> + struct mtk_cqdma_vdesc *active_vdesc;
> void __iomem *base;
> u32 irq;
> -
> refcount_t refcnt;
> -
> - struct tasklet_struct tasklet;
> -
> - /* lock to protect PC */
> spinlock_t lock;
> };
>
> @@ -116,14 +103,10 @@ struct mtk_cqdma_pchan {
> * 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;
> };
>
> /**
> @@ -168,7 +151,7 @@ static struct device *cqdma2dev(struct mtk_cqdma_device *cqdma)
>
> static u32 mtk_dma_read(struct mtk_cqdma_pchan *pc, u32 reg)
> {
> - return readl(pc->base + reg);
> + return readl_relaxed(pc->base + reg);
that can be moved to separate patch and explains why
> }
>
> static void mtk_dma_write(struct mtk_cqdma_pchan *pc, u32 reg, u32 val)
> @@ -202,22 +185,22 @@ 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)
> +static int mtk_cqdma_poll_engine_done(struct mtk_cqdma_pchan *pc)
> {
> u32 status = 0;
>
> - if (!atomic)
> + if (!in_task())
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);
> -
> - return readl_poll_timeout_atomic(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)
> @@ -225,20 +208,17 @@ 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);
> + return mtk_cqdma_poll_engine_done(pc);
> }
>
> 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");
> + 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);
> @@ -253,11 +233,12 @@ static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
> #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_SRC2, 0);
> + mtk_dma_set(pc, MTK_CQDMA_DST2, 0);
if it is mistakenly coded, it should be moved to separate fixup patch
with a tag Fixes: b1f01e48df5a ("dmaengine: mediatek: Add MediaTek
Command-Queue DMA controller for MT6765 SoC")
> #endif
>
> /* setup the length */
> - mtk_dma_set(pc, MTK_CQDMA_LEN1, cvd->len);
> + 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);
> @@ -265,30 +246,17 @@ static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
>
> static void mtk_cqdma_issue_vchan_pending(struct mtk_cqdma_vchan *cvc)
> {
> - struct virt_dma_desc *vd, *vd2;
> + struct virt_dma_desc *vd;
> 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);
> + vd = vchan_next_desc(&cvc->vc);
>
> - /* 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);
> + if (vd && !pc->active_vdesc) {
> + pc->active_vdesc = to_cqdma_vdesc(vd);
> + mtk_cqdma_start(pc, pc->active_vdesc);
> }
> }
>
> @@ -298,100 +266,55 @@ static void mtk_cqdma_issue_vchan_pending(struct mtk_cqdma_vchan *cvc)
> */
> 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 (!cvc->pc->active_vdesc) ? false :
> + (cvc == to_cqdma_vchan(cvc->pc->active_vdesc->ch));
> }
>
> -/*
> - * 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)
> +static void mtk_cqdma_complete_vdesc(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;
> + struct mtk_cqdma_vdesc *cvd;
> + struct virt_dma_desc *vd;
> + size_t tlen;
>
> + cvd = pc->active_vdesc;
> 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);
> + 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 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);
> + /* check whether the VD completed */
> + if (!cvd->len) {
> + /* delete VD from desc_issued */
> + list_del(&cvd->vd.node);
>
> - 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;
> + /* add the VD into list desc_completed */
> + vchan_cookie_complete(&cvd->vd);
>
> - 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);
> + /* get the next active VD */
> + vd = vchan_next_desc(&cvc->vc);
> + pc->active_vdesc = (!vd) ? NULL : to_cqdma_vdesc(vd);
> }
>
> - /* re-enable interrupt before leaving tasklet */
> - enable_irq(pc->irq);
> + /* 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;
> - bool schedule_tasklet = false;
> u32 i;
>
> /* clear interrupt flags for each PC */
> - for (i = 0; i < cqdma->dma_channels; ++i, schedule_tasklet = false) {
> + 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) {
> @@ -399,72 +322,21 @@ static irqreturn_t mtk_cqdma_irq(int irq, void *devid)
> mtk_dma_clr(cqdma->pc[i], MTK_CQDMA_INT_FLAG,
> MTK_CQDMA_INT_FLAG_BIT);
>
> - schedule_tasklet = true;
> + mtk_cqdma_complete_vdesc(cqdma->pc[i]);
> +
> 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;
> + return dma_cookie_status(c, cookie, txstate);
> }
>
> static void mtk_cqdma_issue_pending(struct dma_chan *c)
> @@ -473,7 +345,7 @@ static void mtk_cqdma_issue_pending(struct dma_chan *c)
> unsigned long pc_flags;
> unsigned long vc_flags;
>
> - /* acquire PC's lock before VS's lock for lock dependency in tasklet */
> + /* 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);
>
> @@ -488,124 +360,56 @@ static void mtk_cqdma_issue_pending(struct dma_chan *c)
> 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);
> + struct mtk_cqdma_vdesc *cvd;
> +
> + cvd = kzalloc(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->ch = c;
>
> - /* setup dma channel */
> - cvd[i]->ch = c;
> + /* setup sourece, destination, and length */
> + cvd->len = len;
> + cvd->src = src;
> + cvd->dest = dest;
>
> - /* 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;
> + return vchan_tx_prep(to_virt_chan(c), &cvd->vd, flags);
> }
>
> -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)
> +static int mtk_cqdma_terminate_all(struct dma_chan *c)
> {
> struct mtk_cqdma_vchan *cvc = to_cqdma_vchan(c);
> - bool sync_needed = false;
> + struct virt_dma_chan *vc = to_virt_chan(c);
> unsigned long pc_flags;
> unsigned long vc_flags;
> + LIST_HEAD(head);
>
> - /* 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;
> - }
> + 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);
>
> - spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
> - spin_unlock_irqrestore(&cvc->pc->lock, pc_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;
> + }
>
> - /* waiting for the completion of this VC */
> - if (sync_needed)
> - wait_for_completion(&cvc->issue_completion);
> + /* get VDs from lists */
> + vchan_get_all_descriptors(vc, &head);
>
> - /* free all descriptors in list desc_completed */
> - vchan_synchronize(&cvc->vc);
> + /* free all the VDs */
> + vchan_dma_desc_free_list(vc, &head);
>
> - WARN_ONCE(!list_empty(&cvc->vc.desc_completed),
> - "Desc pending still in list desc_completed\n");
> -}
> + spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
> + spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
>
> -static int mtk_cqdma_terminate_all(struct dma_chan *c)
> -{
> - /* free descriptors not processed yet by hardware */
> - mtk_cqdma_free_inactive_desc(c);
> + break;
> + } while (1);
use wait_for_completion_timeout or something like that instead of
polling here to reduce cpu computing waste and to avoid dead-loop risk
>
> - /* free descriptors being processed by hardware */
> - mtk_cqdma_free_active_desc(c);
> + vchan_synchronize(&cvc->vc);
>
> return 0;
> }
> @@ -618,7 +422,7 @@ static int mtk_cqdma_alloc_chan_resources(struct dma_chan *c)
> u32 i, min_refcnt = U32_MAX, refcnt;
> unsigned long flags;
>
> - /* allocate PC with the minimun refcount */
> + /* 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) {
> @@ -671,8 +475,9 @@ static void mtk_cqdma_free_chan_resources(struct dma_chan *c)
> 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");
> + 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);
> @@ -787,9 +592,9 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
> 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);
> + dev_dbg(&pdev->dev,
> + "Using %u as missing dma-requests property\n",
> + MTK_CQDMA_NR_VCHANS);
>
> cqdma->dma_requests = MTK_CQDMA_NR_VCHANS;
> }
> @@ -797,9 +602,9 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
> 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);
> + dev_dbg(&pdev->dev,
> + "Using %u as missing dma-channels property\n",
> + MTK_CQDMA_NR_PCHANS);
>
> cqdma->dma_channels = MTK_CQDMA_NR_PCHANS;
> }
> @@ -816,7 +621,7 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
> if (!cqdma->pc[i])
> return -ENOMEM;
>
> - INIT_LIST_HEAD(&cqdma->pc[i]->queue);
> + cqdma->pc[i]->active_vdesc = NULL;
> spin_lock_init(&cqdma->pc[i]->lock);
> refcount_set(&cqdma->pc[i]->refcnt, 0);
>
> @@ -860,7 +665,6 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
> 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);
> @@ -884,12 +688,7 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
>
> 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");
> + dev_dbg(&pdev->dev, "MediaTek CQDMA driver registered\n");
>
> return 0;
>
> @@ -923,8 +722,6 @@ static int mtk_cqdma_remove(struct platform_device *pdev)
>
> /* Waits for any pending IRQ handlers to complete */
> synchronize_irq(cqdma->pc[i]->irq);
> -
> - tasklet_kill(&cqdma->pc[i]->tasklet);
> }
>
> /* disable hardware */
> --
> 1.7.9.5
>
>
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> Linux-mediatek mailing list
> Linux-mediatek@...ts.infradead.org
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