* [PATCH] dmaengine: at_hdmac: use dma_address to program DMA hardware
@ 2010-12-15 17:50 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2010-12-15 17:50 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, Nicolas Ferre
In atc_prep_slave_sg() function we use dma_address field of scatterlist with
sg_dma_address() macro instead of sg_phys(). DMA address is already computed
by dma_map_sg() or another mapping function in calling driver.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index ea0ee81..ee7dacd 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -670,7 +670,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (!desc)
goto err_desc_get;
- mem = sg_phys(sg);
+ mem = sg_dma_address(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
@@ -712,7 +712,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (!desc)
goto err_desc_get;
- mem = sg_phys(sg);
+ mem = sg_dma_address(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH] dmaengine: at_hdmac: use dma_address to program DMA hardware
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-10 13:21 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-10 13:21 UTC (permalink / raw)
To: linux-arm-kernel
Le 15/12/2010 18:50, Nicolas Ferre :
> In atc_prep_slave_sg() function we use dma_address field of scatterlist with
> sg_dma_address() macro instead of sg_phys(). DMA address is already computed
> by dma_map_sg() or another mapping function in calling driver.
Ping?
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
> drivers/dma/at_hdmac.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index ea0ee81..ee7dacd 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -670,7 +670,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> if (!desc)
> goto err_desc_get;
>
> - mem = sg_phys(sg);
> + mem = sg_dma_address(sg);
> len = sg_dma_len(sg);
> mem_width = 2;
> if (unlikely(mem & 3 || len & 3))
> @@ -712,7 +712,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> if (!desc)
> goto err_desc_get;
>
> - mem = sg_phys(sg);
> + mem = sg_dma_address(sg);
> len = sg_dma_len(sg);
> mem_width = 2;
> if (unlikely(mem & 3 || len & 3))
--
Nicolas Ferre
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] dmaengine: at_hdmac: use dma_address to program DMA hardware
@ 2011-01-10 13:21 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-10 13:21 UTC (permalink / raw)
To: dan.j.williams; +Cc: linux-arm-kernel, linux-kernel
Le 15/12/2010 18:50, Nicolas Ferre :
> In atc_prep_slave_sg() function we use dma_address field of scatterlist with
> sg_dma_address() macro instead of sg_phys(). DMA address is already computed
> by dma_map_sg() or another mapping function in calling driver.
Ping?
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
> drivers/dma/at_hdmac.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index ea0ee81..ee7dacd 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -670,7 +670,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> if (!desc)
> goto err_desc_get;
>
> - mem = sg_phys(sg);
> + mem = sg_dma_address(sg);
> len = sg_dma_len(sg);
> mem_width = 2;
> if (unlikely(mem & 3 || len & 3))
> @@ -712,7 +712,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> if (!desc)
> goto err_desc_get;
>
> - mem = sg_phys(sg);
> + mem = sg_dma_address(sg);
> len = sg_dma_len(sg);
> mem_width = 2;
> if (unlikely(mem & 3 || len & 3))
--
Nicolas Ferre
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH] dmaengine: at_hdmac: use dma_address to program DMA hardware
2011-01-10 13:21 ` Nicolas Ferre
@ 2011-01-15 0:14 ` Dan Williams
-1 siblings, 0 replies; 18+ messages in thread
From: Dan Williams @ 2011-01-15 0:14 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Jan 10, 2011 at 5:21 AM, Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> Le 15/12/2010 18:50, Nicolas Ferre :
>> In atc_prep_slave_sg() function we use dma_address field of scatterlist with
>> sg_dma_address() macro instead of sg_phys(). DMA address is already computed
>> by dma_map_sg() or another mapping function in calling driver.
>
> Ping?
>
Applied.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] dmaengine: at_hdmac: use dma_address to program DMA hardware
@ 2011-01-15 0:14 ` Dan Williams
0 siblings, 0 replies; 18+ messages in thread
From: Dan Williams @ 2011-01-15 0:14 UTC (permalink / raw)
To: Nicolas Ferre; +Cc: linux-arm-kernel, linux-kernel
On Mon, Jan 10, 2011 at 5:21 AM, Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> Le 15/12/2010 18:50, Nicolas Ferre :
>> In atc_prep_slave_sg() function we use dma_address field of scatterlist with
>> sg_dma_address() macro instead of sg_phys(). DMA address is already computed
>> by dma_map_sg() or another mapping function in calling driver.
>
> Ping?
>
Applied.
^ permalink raw reply [flat|nested] 18+ messages in thread
* [PATCH 2/6] dmaengine: at_hdmac: trivial add precision to unmapping comment
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-12 14:39 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: linux-arm-kernel
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
Hi Dan,
I link this patch series to the previous single patch that I sent a few days
ago so that you will have the whole overview of current (little) improvements
on the Atmel at_hdmac driver.
Thanks, best regards,
Nicolas.
drivers/dma/at_hdmac.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index ee7dacd..a4dd4bc 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -253,7 +253,7 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
/* move myself to free_list */
list_move(&desc->desc_node, &atchan->free_list);
- /* unmap dma addresses */
+ /* unmap dma addresses (not on slave channels) */
if (!atchan->chan_common.private) {
struct device *parent = chan2parent(&atchan->chan_common);
if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread* [PATCH 2/6] dmaengine: at_hdmac: trivial add precision to unmapping comment
@ 2011-01-12 14:39 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, hong.xu, Nicolas Ferre
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
Hi Dan,
I link this patch series to the previous single patch that I sent a few days
ago so that you will have the whole overview of current (little) improvements
on the Atmel at_hdmac driver.
Thanks, best regards,
Nicolas.
drivers/dma/at_hdmac.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index ee7dacd..a4dd4bc 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -253,7 +253,7 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
/* move myself to free_list */
list_move(&desc->desc_node, &atchan->free_list);
- /* unmap dma addresses */
+ /* unmap dma addresses (not on slave channels) */
if (!atchan->chan_common.private) {
struct device *parent = chan2parent(&atchan->chan_common);
if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH 3/6] dmaengine: at_hdmac: no need set ACK in new descriptor
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-12 14:39 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: linux-arm-kernel
Following descriptor flow in at_hdmac driver, descriptor comming from
atc_desc_get() as already DMA_CTRL_ACK flag set. No need to set it again.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index a4dd4bc..4f83431 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -583,7 +583,6 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
- async_tx_ack(&desc->txd);
if (!first) {
first = desc;
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread* [PATCH 3/6] dmaengine: at_hdmac: no need set ACK in new descriptor
@ 2011-01-12 14:39 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, hong.xu, Nicolas Ferre
Following descriptor flow in at_hdmac driver, descriptor comming from
atc_desc_get() as already DMA_CTRL_ACK flag set. No need to set it again.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index a4dd4bc..4f83431 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -583,7 +583,6 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
- async_tx_ack(&desc->txd);
if (!first) {
first = desc;
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH 4/6] dmaengine: at_hdmac: use subsys_initcall instead of module_init
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-12 14:39 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: linux-arm-kernel
From: Eric Xu <hong.xu@atmel.com>
Use subsys_initcall instead of module_init in order to keep DMA engine rolling
before other peripheral drivers.
Signed-off-by: Eric Xu <hong.xu@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 4f83431..a1a0fc6 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1209,7 +1209,7 @@ static int __init at_dma_init(void)
{
return platform_driver_probe(&at_dma_driver, at_dma_probe);
}
-module_init(at_dma_init);
+subsys_initcall(at_dma_init);
static void __exit at_dma_exit(void)
{
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread* [PATCH 4/6] dmaengine: at_hdmac: use subsys_initcall instead of module_init
@ 2011-01-12 14:39 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, hong.xu, Nicolas Ferre
From: Eric Xu <hong.xu@atmel.com>
Use subsys_initcall instead of module_init in order to keep DMA engine rolling
before other peripheral drivers.
Signed-off-by: Eric Xu <hong.xu@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 4f83431..a1a0fc6 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1209,7 +1209,7 @@ static int __init at_dma_init(void)
{
return platform_driver_probe(&at_dma_driver, at_dma_probe);
}
-module_init(at_dma_init);
+subsys_initcall(at_dma_init);
static void __exit at_dma_exit(void)
{
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread* [PATCH 4/6] dmaengine: at_hdmac: use subsys_initcall instead of module_init
2011-01-12 14:39 ` Nicolas Ferre
@ 2011-01-15 0:27 ` Dan Williams
-1 siblings, 0 replies; 18+ messages in thread
From: Dan Williams @ 2011-01-15 0:27 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Jan 12, 2011 at 6:39 AM, Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> From: Eric Xu <hong.xu@atmel.com>
>
> Use subsys_initcall instead of module_init in order to keep DMA engine rolling
> before other peripheral drivers.
>
> Signed-off-by: Eric Xu <hong.xu@atmel.com>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
> ?drivers/dma/at_hdmac.c | ? ?2 +-
> ?1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index 4f83431..a1a0fc6 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -1209,7 +1209,7 @@ static int __init at_dma_init(void)
> ?{
> ? ? ? ?return platform_driver_probe(&at_dma_driver, at_dma_probe);
> ?}
> -module_init(at_dma_init);
> +subsys_initcall(at_dma_init);
If this matters shouldn't we also do this?
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1b61d3a..4d14626 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -90,7 +90,7 @@ config DW_DMAC
can be integrated in chips such as the Atmel AT32ap7000.
config AT_HDMAC
- tristate "Atmel AHB DMA support"
+ bool "Atmel AHB DMA support"
depends on ARCH_AT91SAM9RL || ARCH_AT91SAM9G45
select DMA_ENGINE
help
^ permalink raw reply related [flat|nested] 18+ messages in thread* Re: [PATCH 4/6] dmaengine: at_hdmac: use subsys_initcall instead of module_init
@ 2011-01-15 0:27 ` Dan Williams
0 siblings, 0 replies; 18+ messages in thread
From: Dan Williams @ 2011-01-15 0:27 UTC (permalink / raw)
To: Nicolas Ferre; +Cc: linux-arm-kernel, linux-kernel, hong.xu
On Wed, Jan 12, 2011 at 6:39 AM, Nicolas Ferre <nicolas.ferre@atmel.com> wrote:
> From: Eric Xu <hong.xu@atmel.com>
>
> Use subsys_initcall instead of module_init in order to keep DMA engine rolling
> before other peripheral drivers.
>
> Signed-off-by: Eric Xu <hong.xu@atmel.com>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
> drivers/dma/at_hdmac.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index 4f83431..a1a0fc6 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -1209,7 +1209,7 @@ static int __init at_dma_init(void)
> {
> return platform_driver_probe(&at_dma_driver, at_dma_probe);
> }
> -module_init(at_dma_init);
> +subsys_initcall(at_dma_init);
If this matters shouldn't we also do this?
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1b61d3a..4d14626 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -90,7 +90,7 @@ config DW_DMAC
can be integrated in chips such as the Atmel AT32ap7000.
config AT_HDMAC
- tristate "Atmel AHB DMA support"
+ bool "Atmel AHB DMA support"
depends on ARCH_AT91SAM9RL || ARCH_AT91SAM9G45
select DMA_ENGINE
help
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH 5/6] dmaengine: at_hdmac: flags located in first descriptor
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-12 14:39 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: linux-arm-kernel
Place flags on first descriptor of chain instead of last.
This is the one used by atc_chain_complete() function while unmapping.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index a1a0fc6..99942a5 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -603,7 +603,7 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
- desc->txd.flags = flags; /* client is in control of this ack */
+ first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
@@ -748,8 +748,8 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
first->txd.cookie = -EBUSY;
first->len = total_len;
- /* last link descriptor of list is responsible of flags */
- prev->txd.flags = flags; /* client is in control of this ack */
+ /* first link descriptor of list is responsible of flags */
+ first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH 5/6] dmaengine: at_hdmac: flags located in first descriptor
@ 2011-01-12 14:39 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, hong.xu, Nicolas Ferre
Place flags on first descriptor of chain instead of last.
This is the one used by atc_chain_complete() function while unmapping.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index a1a0fc6..99942a5 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -603,7 +603,7 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
- desc->txd.flags = flags; /* client is in control of this ack */
+ first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
@@ -748,8 +748,8 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
first->txd.cookie = -EBUSY;
first->len = total_len;
- /* last link descriptor of list is responsible of flags */
- prev->txd.flags = flags; /* client is in control of this ack */
+ /* first link descriptor of list is responsible of flags */
+ first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread
* [PATCH 6/6] dmaengine: at_hdmac: fix race while monitoring channel status
2010-12-15 17:50 ` Nicolas Ferre
@ 2011-01-12 14:39 ` Nicolas Ferre
-1 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: linux-arm-kernel
We were reading channel status then taking a lock. This lead to a race because
this lock may delay us and then make this channel not idle anymore.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 99942a5..3d7d705 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -853,11 +853,11 @@ static void atc_issue_pending(struct dma_chan *chan)
dev_vdbg(chan2dev(chan), "issue_pending\n");
+ spin_lock_bh(&atchan->lock);
if (!atc_chan_is_enabled(atchan)) {
- spin_lock_bh(&atchan->lock);
atc_advance_work(atchan);
- spin_unlock_bh(&atchan->lock);
}
+ spin_unlock_bh(&atchan->lock);
}
/**
--
1.7.3
^ permalink raw reply related [flat|nested] 18+ messages in thread* [PATCH 6/6] dmaengine: at_hdmac: fix race while monitoring channel status
@ 2011-01-12 14:39 ` Nicolas Ferre
0 siblings, 0 replies; 18+ messages in thread
From: Nicolas Ferre @ 2011-01-12 14:39 UTC (permalink / raw)
To: dan.j.williams, linux-arm-kernel; +Cc: linux-kernel, hong.xu, Nicolas Ferre
We were reading channel status then taking a lock. This lead to a race because
this lock may delay us and then make this channel not idle anymore.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
drivers/dma/at_hdmac.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 99942a5..3d7d705 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -853,11 +853,11 @@ static void atc_issue_pending(struct dma_chan *chan)
dev_vdbg(chan2dev(chan), "issue_pending\n");
+ spin_lock_bh(&atchan->lock);
if (!atc_chan_is_enabled(atchan)) {
- spin_lock_bh(&atchan->lock);
atc_advance_work(atchan);
- spin_unlock_bh(&atchan->lock);
}
+ spin_unlock_bh(&atchan->lock);
}
/**
--
1.7.3
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