2023-10-11 14:17:43

by Kory Maincent

[permalink] [raw]
Subject: [PATCH v4 0/6] Fix support of dw-edma HDMA NATIVE IP in remote setup

This patch series fix the support of dw-edma HDMA NATIVE IP.
I can only test it in remote HDMA IP setup with single dma transfer, but
with these fixes it works properly.

Few fixes has also been added for eDMA version. Similarly to HDMA I have
tested only eDMA in remote setup.

Changes in v2:
- Update comments and fix typos.
- Removed patches that tackle hypothetical bug and then were not pertinent.
- Add the similar HDMA race condition in remote setup fix to eDMA IP driver.

Changes in v3:
- Fix comment style.
- Split a patch in two to differ bug fix and simple harmless typo.

Changes in v4:
- Update patch git commit message.
- Link to v3: https://lore.kernel.org/r/[email protected]

Signed-off-by: Kory Maincent <[email protected]>
---
Kory Maincent (6):
dmaengine: dw-edma: Fix the ch_count hdma callback
dmaengine: dw-edma: Fix wrong interrupt bit set
dmaengine: dw-edma: Typo fix
dmaengine: dw-edma: Add HDMA remote interrupt configuration
dmaengine: dw-edma: HDMA: Add sync read before starting the DMA transfer in remote setup
dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup

drivers/dma/dw-edma/dw-edma-v0-core.c | 17 +++++++++++++++
drivers/dma/dw-edma/dw-hdma-v0-core.c | 39 +++++++++++++++++++++++------------
drivers/dma/dw-edma/dw-hdma-v0-regs.h | 2 +-
3 files changed, 44 insertions(+), 14 deletions(-)
---
base-commit: 8bf914570650ec5858e18554d70d2838cef01de1
change-id: 20231011-b4-feature_hdma_mainline-b6c57f8e3b5d

Best regards,
--
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com


2023-10-11 14:17:43

by Kory Maincent

[permalink] [raw]
Subject: [PATCH v4 5/6] dmaengine: dw-edma: HDMA: Add sync read before starting the DMA transfer in remote setup

The Linked list element and pointer are not stored in the same memory as
the HDMA 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: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
Reviewed-by: Serge Semin <[email protected]>
Signed-off-by: Kory Maincent <[email protected]>
---

Changes in v2:
- Move the sync read in a function.
- Add commments

Changes in v4:
- Update git commit message.
---
drivers/dma/dw-edma/dw-hdma-v0-core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
index 04b0bcb6ded9..13b6aec6a6de 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
@@ -222,6 +222,20 @@ static void dw_hdma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
dw_hdma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
}

+static void dw_hdma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
+{
+ /*
+ * In case of remote HDMA engine setup, the DW PCIe RP/EP internals
+ * 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 posted 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);
+}
+
static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -252,6 +266,9 @@ static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
/* Set consumer cycle */
SET_CH_32(dw, chan->dir, chan->id, cycle_sync,
HDMA_V0_CONSUMER_CYCLE_STAT | HDMA_V0_CONSUMER_CYCLE_BIT);
+
+ dw_hdma_v0_sync_ll_data(chunk);
+
/* Doorbell */
SET_CH_32(dw, chan->dir, chan->id, doorbell, HDMA_V0_DOORBELL_START);
}

--
2.25.1

2023-10-11 14:17:51

by Kory Maincent

[permalink] [raw]
Subject: [PATCH v4 6/6] dmaengine: dw-edma: eDMA: Add sync read before starting the DMA transfer in remote setup

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 <[email protected]>
Signed-off-by: Kory Maincent <[email protected]>
---

Changes in v2:
- New patch

Changes in v4:
- Update git commit message.
---
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 b38786f0ad79..6245b720fbfe 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -346,6 +346,20 @@ 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);
}

+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 internals
+ * 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 posted 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);
+}
+
static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
@@ -412,6 +426,9 @@ static 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));

--
2.25.1

2023-10-11 14:17:53

by Kory Maincent

[permalink] [raw]
Subject: [PATCH v4 2/6] dmaengine: dw-edma: Fix wrong interrupt bit set

Fix "HDMA_V0_LOCAL_STOP_INT_EN" to "HDMA_V0_LOCAL_ABORT_INT_EN" as the STOP
bit is already set in the same line.

Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
Signed-off-by: Kory Maincent <[email protected]>
Reviewed-by: Serge Semin <[email protected]>
---

Changes in v3:
- Split the patch in two to differ bug fix and simple harmless typo.
---
drivers/dma/dw-edma/dw-hdma-v0-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
index 1f4cb7db5475..108f9127aaaa 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
@@ -236,7 +236,7 @@ static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
/* Interrupt enable&unmask - done, abort */
tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup) |
HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK |
- HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_STOP_INT_EN;
+ HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_ABORT_INT_EN;
SET_CH_32(dw, chan->dir, chan->id, int_setup, tmp);
/* Channel control */
SET_CH_32(dw, chan->dir, chan->id, control1, HDMA_V0_LINKLIST_EN);

--
2.25.1

2023-10-11 14:17:57

by Kory Maincent

[permalink] [raw]
Subject: [PATCH v4 3/6] dmaengine: dw-edma: Typo fix

Fix "HDMA_V0_REMOTEL_STOP_INT_EN" typo error

Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
Signed-off-by: Kory Maincent <[email protected]>
Reviewed-by: Serge Semin <[email protected]>
---

Changes in v3:
- Split the patch in two to differ bug fix and simple harmless typo.
---
drivers/dma/dw-edma/dw-hdma-v0-regs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/dw-edma/dw-hdma-v0-regs.h b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
index a974abdf8aaf..eab5fd7177e5 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-regs.h
+++ b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
@@ -15,7 +15,7 @@
#define HDMA_V0_LOCAL_ABORT_INT_EN BIT(6)
#define HDMA_V0_REMOTE_ABORT_INT_EN BIT(5)
#define HDMA_V0_LOCAL_STOP_INT_EN BIT(4)
-#define HDMA_V0_REMOTEL_STOP_INT_EN BIT(3)
+#define HDMA_V0_REMOTE_STOP_INT_EN BIT(3)
#define HDMA_V0_ABORT_INT_MASK BIT(2)
#define HDMA_V0_STOP_INT_MASK BIT(0)
#define HDMA_V0_LINKLIST_EN BIT(0)

--
2.25.1