From 30c1dc0ff30b5552e8af555265dbeac5637cbb48 Mon Sep 17 00:00:00 2001 From: Tushar Behera Date: Wed, 23 May 2012 16:47:31 +0530 Subject: [PATCH 1/4] dmaengine: pl330: dont complete descriptor for cyclic dma Commit eab215855803 ("dmaengine: pl330: dont complete descriptor for cyclic dma") wrongly completes descriptor for cyclic dma, hence following BUG_ON is still hit with cyclic DMA operations. kernel BUG at drivers/dma/dmaengine.h:53! Signed-off-by: Tushar Behera Acked-by: Jassi Brar Signed-off-by: Vinod Koul Cc: stable --- drivers/dma/pl330.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index cbcc28e79be63..6d550421da7a4 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2321,7 +2321,7 @@ static void pl330_tasklet(unsigned long data) /* Pick up ripe tomatoes */ list_for_each_entry_safe(desc, _dt, &pch->work_list, node) if (desc->status == DONE) { - if (pch->cyclic) + if (!pch->cyclic) dma_cookie_complete(&desc->txd); list_move_tail(&desc->node, &list); } From 8e2e27c7444ba7880aa0a4cb07a79de130d0ed93 Mon Sep 17 00:00:00 2001 From: Richard Zhao Date: Mon, 4 Jun 2012 09:17:24 +0800 Subject: [PATCH 2/4] dma: imx-sdma: buf_tail should be initialize in prepare function This fix audio underrun issue. When SNDRV_PCM_TRIGGER_STOP and SNDRV_PCM_TRIGGER_START, it calls prepare again. buf_tail should be reset to zero. So move buf_tail initialization into prepare function. Signed-off-by: Richard Zhao Acked-by: Shawn Guo Signed-off-by: Vinod Koul --- drivers/dma/imx-sdma.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index fb4f4990f5ebf..1dc2a4ad0026d 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -815,8 +815,6 @@ static int sdma_request_channel(struct sdma_channel *sdmac) init_completion(&sdmac->done); - sdmac->buf_tail = 0; - return 0; out: @@ -927,6 +925,8 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg( sdmac->flags = 0; + sdmac->buf_tail = 0; + dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n", sg_len, channel); @@ -1027,6 +1027,8 @@ static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic( sdmac->status = DMA_IN_PROGRESS; + sdmac->buf_tail = 0; + sdmac->flags |= IMX_DMA_SG_LOOP; sdmac->direction = direction; ret = sdma_load_context(sdmac); From 5a67ac572e102f7d877b8a3a18a59315186e3e99 Mon Sep 17 00:00:00 2001 From: Sachin Kamat Date: Mon, 4 Jun 2012 17:09:45 +0530 Subject: [PATCH 3/4] DMA: PL330: Add missing static storage class specifier Fixes the following sparse warning: drivers/dma/pl330.c:2542:5: warning: symbol 'add_desc' was not declared. Should it be static? Signed-off-by: Sachin Kamat Signed-off-by: Vinod Koul --- drivers/dma/pl330.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 6d550421da7a4..3ce7d553a7460 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2539,7 +2539,7 @@ static inline void _init_desc(struct dma_pl330_desc *desc) } /* Returns the number of descriptors added to the DMAC pool */ -int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count) +static int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count) { struct dma_pl330_desc *desc; unsigned long flags; From fdec53d5203ee3d44be7c09d1524e3a6287d46a7 Mon Sep 17 00:00:00 2001 From: Javi Merino Date: Wed, 13 Jun 2012 15:07:00 +0100 Subject: [PATCH 4/4] DMA: PL330: Fix racy mutex unlock pl330_update() stores a pointer to the thrd->req that finished, which contains a pointer to the corresponding pl330_req. This is done with the pl330_lock held. Then, it iterates through the req_done list, calling the callback for each of the requests that are done. The problem is that the driver releases the lock before calling the callback for each of the callbacks. pl330_submit_req() running in another processor can then acquire the lock and insert another request in one of the thrd->req that hasn't been processed yet, replacing the pointer to pl330_req there. When the callback returns in pl330_update() and the next rqdone is popped from the list, it dereferences the pl330_req pointer to the just scheduled pl330_req, instead of the one that has finished, calling pl330 with the wrong r. This patch fixes this by storing the pointer to pl330_req directly in the list. Signed-off-by: Javi Merino Cc: Jassi Brar Acked-by: Jassi Brar Signed-off-by: Vinod Koul --- drivers/dma/pl330.c | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 3ce7d553a7460..e4feba6b03c00 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -392,6 +392,8 @@ struct pl330_req { struct pl330_reqcfg *cfg; /* Pointer to first xfer in the request. */ struct pl330_xfer *x; + /* Hook to attach to DMAC's list of reqs with due callback */ + struct list_head rqd; }; /* @@ -461,8 +463,6 @@ struct _pl330_req { /* Number of bytes taken to setup MC for the req */ u32 mc_len; struct pl330_req *r; - /* Hook to attach to DMAC's list of reqs with due callback */ - struct list_head rqd; }; /* ToBeDone for tasklet */ @@ -1683,7 +1683,7 @@ static void pl330_dotask(unsigned long data) /* Returns 1 if state was updated, 0 otherwise */ static int pl330_update(const struct pl330_info *pi) { - struct _pl330_req *rqdone; + struct pl330_req *rqdone, *tmp; struct pl330_dmac *pl330; unsigned long flags; void __iomem *regs; @@ -1750,7 +1750,10 @@ static int pl330_update(const struct pl330_info *pi) if (active == -1) /* Aborted */ continue; - rqdone = &thrd->req[active]; + /* Detach the req */ + rqdone = thrd->req[active].r; + thrd->req[active].r = NULL; + mark_free(thrd, active); /* Get going again ASAP */ @@ -1762,20 +1765,11 @@ static int pl330_update(const struct pl330_info *pi) } /* Now that we are in no hurry, do the callbacks */ - while (!list_empty(&pl330->req_done)) { - struct pl330_req *r; - - rqdone = container_of(pl330->req_done.next, - struct _pl330_req, rqd); - - list_del_init(&rqdone->rqd); - - /* Detach the req */ - r = rqdone->r; - rqdone->r = NULL; + list_for_each_entry_safe(rqdone, tmp, &pl330->req_done, rqd) { + list_del(&rqdone->rqd); spin_unlock_irqrestore(&pl330->lock, flags); - _callback(r, PL330_ERR_NONE); + _callback(rqdone, PL330_ERR_NONE); spin_lock_irqsave(&pl330->lock, flags); }