* [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@ 2024-12-05 9:37 jianqi.ren.cn
2024-12-05 13:33 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
0 siblings, 2 replies; 10+ messages in thread
From: jianqi.ren.cn @ 2024-12-05 9:37 UTC (permalink / raw)
To: kory.maincent, gregkh; +Cc: stable
From: Kory Maincent <kory.maincent@bootlin.com>
[ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
---
drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index a3816ba63285..4fe83d5a25b6 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -357,6 +357,20 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
#endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
+{
+ /*
+ * In case of remote eDMA engine setup, the DW PCIe RP/EP internal
+ * configuration registers and application memory are normally accessed
+ * over different buses. Ensure LL-data reaches the memory before the
+ * doorbell register is toggled by issuing the dummy-read from the remote
+ * LL memory in a hope that the MRd TLP will return only after the
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
+ readl(chunk->ll_region.vaddr.io);
+}
+
void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -423,6 +437,9 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
+
+ dw_edma_v0_sync_ll_data(chunk);
+
/* Doorbell */
SET_RW_32(dw, chan->dir, doorbell,
FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id));
--
2.39.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-05 9:37 jianqi.ren.cn
@ 2024-12-05 13:33 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
1 sibling, 0 replies; 10+ messages in thread
From: Sasha Levin @ 2024-12-05 13:33 UTC (permalink / raw)
To: stable; +Cc: jianqi.ren.cn, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: bbcc1c83f343e580c3aa1f2a8593343bf7b55bba
WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Kory Maincent <kory.maincent@bootlin.com>
Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (exact SHA1)
6.6.y | Present (different SHA1: d24fe6d5a1cf)
6.1.y | Not found
Note: The patch differs from the upstream commit:
---
1: bbcc1c83f343e ! 1: 9152d76cc2fe0 dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@@ Metadata
## Commit message ##
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
+ [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
+
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
@@ Commit message
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
+ Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
## drivers/dma/dw-edma/dw-edma-v0-core.c ##
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
- dw_edma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
+ #endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(s
+ readl(chunk->ll_region.vaddr.io);
+}
+
- static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
-@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+@@ drivers/dma/dw-edma/dw-edma-v0-core.c: void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y | Success | Failed |
Build Errors:
Build error for stable/linux-6.1.y:
drivers/dma/dw-edma/dw-edma-v0-core.c: In function 'dw_edma_v0_sync_ll_data':
drivers/dma/dw-edma/dw-edma-v0-core.c:371:45: error: request for member 'io' in something not a structure or union
371 | readl(chunk->ll_region.vaddr.io);
| ^
make[4]: *** [scripts/Makefile.build:250: drivers/dma/dw-edma/dw-edma-v0-core.o] Error 1
make[4]: Target 'drivers/dma/dw-edma/' not remade because of errors.
make[3]: *** [scripts/Makefile.build:503: drivers/dma/dw-edma] Error 2
make[3]: Target 'drivers/dma/' not remade because of errors.
make[2]: *** [scripts/Makefile.build:503: drivers/dma] Error 2
make[2]: Target 'drivers/' not remade because of errors.
make[1]: *** [scripts/Makefile.build:503: drivers] Error 2
make[1]: Target './' not remade because of errors.
make: *** [Makefile:2009: .] Error 2
make: Target '__all' not remade because of errors.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@ 2024-12-06 3:22 jianqi.ren.cn
2024-12-06 17:11 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
0 siblings, 2 replies; 10+ messages in thread
From: jianqi.ren.cn @ 2024-12-06 3:22 UTC (permalink / raw)
To: kory.maincent, gregkh; +Cc: stable
From: Kory Maincent <kory.maincent@bootlin.com>
[ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
---
drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index a3816ba63285..aeaae28fab85 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -357,6 +357,20 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
#endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
+{
+ /*
+ * In case of remote eDMA engine setup, the DW PCIe RP/EP internal
+ * configuration registers and application memory are normally accessed
+ * over different buses. Ensure LL-data reaches the memory before the
+ * doorbell register is toggled by issuing the dummy-read from the remote
+ * LL memory in a hope that the MRd TLP will return only after the
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
+ readl(chunk->ll_region.vaddr);
+}
+
void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -423,6 +437,9 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
+
+ dw_edma_v0_sync_ll_data(chunk);
+
/* Doorbell */
SET_RW_32(dw, chan->dir, doorbell,
FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id));
--
2.39.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-06 3:22 [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup jianqi.ren.cn
@ 2024-12-06 17:11 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
1 sibling, 0 replies; 10+ messages in thread
From: Sasha Levin @ 2024-12-06 17:11 UTC (permalink / raw)
To: stable; +Cc: jianqi.ren.cn, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: bbcc1c83f343e580c3aa1f2a8593343bf7b55bba
WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Kory Maincent <kory.maincent@bootlin.com>
Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: d24fe6d5a1cf)
6.1.y | Not found
Note: The patch differs from the upstream commit:
---
1: bbcc1c83f343e ! 1: da1ca4c28e390 dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@@ Metadata
## Commit message ##
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
+ [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
+
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
@@ Commit message
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
+ Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
## drivers/dma/dw-edma/dw-edma-v0-core.c ##
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
- dw_edma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
+ #endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(s
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
-+ readl(chunk->ll_region.vaddr.io);
++ readl(chunk->ll_region.vaddr);
+}
+
- static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
-@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+@@ drivers/dma/dw-edma/dw-edma-v0-core.c: void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y | Success | Success |
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@ 2024-12-09 4:26 jianqi.ren.cn
2024-12-09 14:35 ` Sasha Levin
0 siblings, 1 reply; 10+ messages in thread
From: jianqi.ren.cn @ 2024-12-09 4:26 UTC (permalink / raw)
To: kory.maincent, gregkh
Cc: stable, gustavo.pimentel, vkoul, dmaengine, linux-kernel
From: Kory Maincent <kory.maincent@bootlin.com>
[ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
---
drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index a3816ba63285..aeaae28fab85 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -357,6 +357,20 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
#endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
+{
+ /*
+ * In case of remote eDMA engine setup, the DW PCIe RP/EP internal
+ * configuration registers and application memory are normally accessed
+ * over different buses. Ensure LL-data reaches the memory before the
+ * doorbell register is toggled by issuing the dummy-read from the remote
+ * LL memory in a hope that the MRd TLP will return only after the
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
+ readl(chunk->ll_region.vaddr);
+}
+
void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -423,6 +437,9 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
+
+ dw_edma_v0_sync_ll_data(chunk);
+
/* Doorbell */
SET_RW_32(dw, chan->dir, doorbell,
FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id));
--
2.39.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-09 4:26 jianqi.ren.cn
@ 2024-12-09 14:35 ` Sasha Levin
0 siblings, 0 replies; 10+ messages in thread
From: Sasha Levin @ 2024-12-09 14:35 UTC (permalink / raw)
To: stable; +Cc: jianqi.ren.cn, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: bbcc1c83f343e580c3aa1f2a8593343bf7b55bba
WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Kory Maincent <kory.maincent@bootlin.com>
Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: d24fe6d5a1cf)
6.1.y | Not found
Note: The patch differs from the upstream commit:
---
1: bbcc1c83f343e ! 1: b768445d42818 dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@@ Metadata
## Commit message ##
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
+ [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
+
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
@@ Commit message
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
+ Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
## drivers/dma/dw-edma/dw-edma-v0-core.c ##
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
- dw_edma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
+ #endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(s
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
-+ readl(chunk->ll_region.vaddr.io);
++ readl(chunk->ll_region.vaddr);
+}
+
- static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
-@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+@@ drivers/dma/dw-edma/dw-edma-v0-core.c: void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y | Success | Success |
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-06 3:22 [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup jianqi.ren.cn
2024-12-06 17:11 ` Sasha Levin
@ 2024-12-11 8:15 ` Greg KH
1 sibling, 0 replies; 10+ messages in thread
From: Greg KH @ 2024-12-11 8:15 UTC (permalink / raw)
To: jianqi.ren.cn; +Cc: kory.maincent, stable
On Fri, Dec 06, 2024 at 11:22:14AM +0800, jianqi.ren.cn@windriver.com wrote:
> From: Kory Maincent <kory.maincent@bootlin.com>
>
> [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
Please cc: all relevant people on backports.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-05 9:37 jianqi.ren.cn
2024-12-05 13:33 ` Sasha Levin
@ 2024-12-11 8:15 ` Greg KH
1 sibling, 0 replies; 10+ messages in thread
From: Greg KH @ 2024-12-11 8:15 UTC (permalink / raw)
To: jianqi.ren.cn; +Cc: kory.maincent, stable
On Thu, Dec 05, 2024 at 05:37:58PM +0800, jianqi.ren.cn@windriver.com wrote:
> From: Kory Maincent <kory.maincent@bootlin.com>
>
> [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
Please cc: all relevant people on backports.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@ 2024-12-11 10:04 jianqi.ren.cn
2024-12-11 16:32 ` Sasha Levin
0 siblings, 1 reply; 10+ messages in thread
From: jianqi.ren.cn @ 2024-12-11 10:04 UTC (permalink / raw)
To: kory.maincent, gregkh
Cc: patches, fancer.lancer, manivannan.sadhasivam, vkoul, stable,
gustavo.pimentel, dmaengine, linux-kernel
From: Kory Maincent <kory.maincent@bootlin.com>
[ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
In remote setup we can only use a readl to the memory to assure the full
write has occurred.
Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
---
drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index a3816ba63285..aeaae28fab85 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -357,6 +357,20 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
#endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
+{
+ /*
+ * In case of remote eDMA engine setup, the DW PCIe RP/EP internal
+ * configuration registers and application memory are normally accessed
+ * over different buses. Ensure LL-data reaches the memory before the
+ * doorbell register is toggled by issuing the dummy-read from the remote
+ * LL memory in a hope that the MRd TLP will return only after the
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
+ readl(chunk->ll_region.vaddr);
+}
+
void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -423,6 +437,9 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
+
+ dw_edma_v0_sync_ll_data(chunk);
+
/* Doorbell */
SET_RW_32(dw, chan->dir, doorbell,
FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id));
--
2.39.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
2024-12-11 10:04 jianqi.ren.cn
@ 2024-12-11 16:32 ` Sasha Levin
0 siblings, 0 replies; 10+ messages in thread
From: Sasha Levin @ 2024-12-11 16:32 UTC (permalink / raw)
To: stable; +Cc: jianqi.ren.cn, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: bbcc1c83f343e580c3aa1f2a8593343bf7b55bba
WARNING: Author mismatch between patch and upstream commit:
Backport author: <jianqi.ren.cn@windriver.com>
Commit author: Kory Maincent <kory.maincent@bootlin.com>
Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: d24fe6d5a1cf)
6.1.y | Not found
Note: The patch differs from the upstream commit:
---
1: bbcc1c83f343e ! 1: 7df439bf2621c dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
@@ Metadata
## Commit message ##
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup
+ [ Upstream commit bbcc1c83f343e580c3aa1f2a8593343bf7b55bba ]
+
The Linked list element and pointer are not stored in the same memory as
the eDMA controller register. If the doorbell register is toggled before
the full write of the linked list a race condition error will occur.
@@ Commit message
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240129-b4-feature_hdma_mainline-v7-6-8e8c1acb7a46@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
+ Signed-off-by: Jianqi Ren <jianqi.ren.cn@windriver.com>
## drivers/dma/dw-edma/dw-edma-v0-core.c ##
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
- dw_edma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
+ #endif /* CONFIG_64BIT */
}
+static void dw_edma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_write_chunk(s
+ * last MWr TLP is completed
+ */
+ if (!(chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
-+ readl(chunk->ll_region.vaddr.io);
++ readl(chunk->ll_region.vaddr);
+}
+
- static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
-@@ drivers/dma/dw-edma/dw-edma-v0-core.c: static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+@@ drivers/dma/dw-edma/dw-edma-v0-core.c: void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
SET_CH_32(dw, chan->dir, chan->id, llp.msb,
upper_32_bits(chunk->ll_region.paddr));
}
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y | Success | Success |
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2024-12-11 16:32 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2024-12-06 3:22 [PATCH 6.1.y] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup jianqi.ren.cn
2024-12-06 17:11 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
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2024-12-11 10:04 jianqi.ren.cn
2024-12-11 16:32 ` Sasha Levin
2024-12-09 4:26 jianqi.ren.cn
2024-12-09 14:35 ` Sasha Levin
2024-12-05 9:37 jianqi.ren.cn
2024-12-05 13:33 ` Sasha Levin
2024-12-11 8:15 ` Greg KH
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