[PATCH v8 2/4] dmaengine: mediatek-cqdma: remove redundant queue structure

From: EastL Lee
Date: Wed Dec 23 2020 - 04:32:12 EST

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.

Signed-off-by: EastL Lee <EastL.Lee@xxxxxxxxxxxx>
---
drivers/dma/mediatek/mtk-cqdma.c | 382 ++++++++++-----------------------------
1 file changed, 93 insertions(+), 289 deletions(-)

diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
index 41ef9f1..905bbcb 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 +103,11 @@ 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;
+ struct completion cmp;
};

/**
@@ -202,22 +186,22 @@ 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())
+ 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(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)
@@ -225,20 +209,17 @@ 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, true);
+ 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);
@@ -257,7 +238,8 @@ static void mtk_cqdma_start(struct mtk_cqdma_pchan *pc,
#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 +247,17 @@ 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);
-
- /* 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);
+ vd = vchan_next_desc(&cvc->vc);

- /* 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 +267,55 @@ 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);
+ /* check whether the VD completed */
+ if (!cvd->len) {
+ /* delete VD from desc_issued */
+ list_del(&cvd->vd.node);

- /* 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);
+ /* add the VD into list desc_completed */
+ vchan_cookie_complete(&cvd->vd);

- /* 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(struct tasklet_struct *t)
-{
- struct mtk_cqdma_pchan *pc = from_tasklet(pc, t, tasklet);
- 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);
+ /* 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 +323,21 @@ 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)
@@ -473,13 +346,17 @@ 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);

+ init_completion(&cvc->cmp);
+
if (vchan_issue_pending(&cvc->vc))
mtk_cqdma_issue_vchan_pending(cvc);

+ complete(&cvc->cmp);
+
spin_unlock_irqrestore(&cvc->vc.lock, vc_flags);
spin_unlock_irqrestore(&cvc->pc->lock, pc_flags);
}
@@ -488,125 +365,50 @@ 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[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;
+ /* setup dma channel */
+ cvd->ch = c;

- 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;
- }
+ /* setup sourece, destination, and length */
+ cvd->len = len;
+ cvd->src = src;
+ cvd->dest = dest;

- 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);
+
+ /* wait for the VC to be inactive */
+ if (!wait_for_completion_timeout(&cvc->cmp, msecs_to_jiffies(3000)))
+ return -EAGAIN;

/* 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;
- }
+ /* 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);

- /* 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;
}

@@ -618,7 +420,7 @@ 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 +473,9 @@ 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, true) < 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);
@@ -816,10 +619,18 @@ 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);
- cqdma->pc[i]->base = devm_platform_ioremap_resource(pdev, i);
+
+ 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);

@@ -852,7 +663,6 @@ 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);
@@ -876,10 +686,6 @@ 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_setup(&cqdma->pc[i]->tasklet, mtk_cqdma_tasklet_cb);
-
dev_info(&pdev->dev, "MediaTek CQDMA driver registered\n");

return 0;
@@ -914,8 +720,6 @@ 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 */
--
1.9.1