[PATCH v4 0/3] Add compatible for Tegra234 GPCDMA

[PATCH v4 0/3] Add compatible for Tegra234 GPCDMA

[Akhil R]

In cases where the client bus gets corrupted or if the end device
ceases to send/receive data, the DMA could wait for the data forever.
Tegra234 supports recovery of such channels hung in flush mode.

Add a separate compatible for Tegra234 so that this scenario can be
handled in the driver.

v3->v4:
    * Updated binding doc to use enum for compatible instead of const
v2->v3:
    * Updated binding docs and device tree compatible
v1->v2:
    * split device tree change to a different patch.
    * Update commit message


Akhil R (3):
  dt-bindings: dmaengine: Add compatible for Tegra234
  dmaengine: tegra: Add terminate() for Tegra234
  arm64: tegra: Update compatible for Tegra234 GPCDMA

 .../bindings/dma/nvidia,tegra186-gpc-dma.yaml |  4 ++-
 arch/arm64/boot/dts/nvidia/tegra234.dtsi      |  4 +--
 drivers/dma/tegra186-gpc-dma.c                | 26 +++++++++++++++++--
 3 files changed, 29 insertions(+), 5 deletions(-)

-- 
2.17.1

[PATCH v4 1/3] dt-bindings: dmaengine: Add compatible for Tegra234

[Akhil R]

Document the compatible string used by GPCDMA controller for Tegra234.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 .../devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml      | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
index 9dd1476d1849..7e575296df0c 100644
--- a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
+++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
@@ -23,7 +23,9 @@ properties:
     oneOf:
       - const: nvidia,tegra186-gpcdma
       - items:
-          - const: nvidia,tegra194-gpcdma
+          - enum:
+              - nvidia,tegra234-gpcdma
+              - nvidia,tegra194-gpcdma
           - const: nvidia,tegra186-gpcdma
 
   "#dma-cells":
-- 
2.17.1

[PATCH v4 2/3] dmaengine: tegra: Add terminate() for Tegra234

[Akhil R]

In certain cases where the DMA client bus gets corrupted or if the
end device ceases to send/receive data, DMA can wait indefinitely
for the data to be received/sent. Attempting to terminate the transfer
will put the DMA in pause flush mode and it remains there.

The channel is irrecoverable once this pause times out in Tegra194 and
earlier chips. Whereas, from Tegra234, it can be recovered by disabling
the channel and reprograming it.

Hence add a new terminate() function that ignores the outcome of
dma_pause() so that terminate_all() can proceed to disable the channel.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/dma/tegra186-gpc-dma.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index 05cd451f541d..fa9bda4a2bc6 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -157,8 +157,8 @@
  * If any burst is in flight and DMA paused then this is the time to complete
  * on-flight burst and update DMA status register.
  */
-#define TEGRA_GPCDMA_BURST_COMPLETE_TIME	20
-#define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT	100
+#define TEGRA_GPCDMA_BURST_COMPLETE_TIME	10
+#define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT	5000 /* 5 msec */
 
 /* Channel base address offset from GPCDMA base address */
 #define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET	0x20000
@@ -432,6 +432,17 @@ static int tegra_dma_device_resume(struct dma_chan *dc)
 	return 0;
 }
 
+static inline int tegra_dma_pause_noerr(struct tegra_dma_channel *tdc)
+{
+	/* Return 0 irrespective of PAUSE status.
+	 * This is useful to recover channels that can exit out of flush
+	 * state when the channel is disabled.
+	 */
+
+	tegra_dma_pause(tdc);
+	return 0;
+}
+
 static void tegra_dma_disable(struct tegra_dma_channel *tdc)
 {
 	u32 csr, status;
@@ -1292,6 +1303,14 @@ static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
 	.terminate = tegra_dma_pause,
 };
 
+static const struct tegra_dma_chip_data tegra234_dma_chip_data = {
+	.nr_channels = 31,
+	.channel_reg_size = SZ_64K,
+	.max_dma_count = SZ_1G,
+	.hw_support_pause = true,
+	.terminate = tegra_dma_pause_noerr,
+};
+
 static const struct of_device_id tegra_dma_of_match[] = {
 	{
 		.compatible = "nvidia,tegra186-gpcdma",
@@ -1299,6 +1318,9 @@ static const struct of_device_id tegra_dma_of_match[] = {
 	}, {
 		.compatible = "nvidia,tegra194-gpcdma",
 		.data = &tegra194_dma_chip_data,
+	}, {
+		.compatible = "nvidia,tegra234-gpcdma",
+		.data = &tegra234_dma_chip_data,
 	}, {
 	},
 };
-- 
2.17.1

[PATCH v4 3/3] arm64: tegra: Update compatible for Tegra234 GPCDMA

[Akhil R]

Use the compatible specific to Tegra234 for GPCDMA to support
additional features.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra234.dtsi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/nvidia/tegra234.dtsi b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
index cf611eff7f6b..c3d2e48994d1 100644
--- a/arch/arm64/boot/dts/nvidia/tegra234.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
@@ -22,8 +22,8 @@
 		ranges = <0x0 0x0 0x0 0x40000000>;
 
 		gpcdma: dma-controller@2600000 {
-			compatible = "nvidia,tegra194-gpcdma",
-				      "nvidia,tegra186-gpcdma";
+			compatible = "nvidia,tegra234-gpcdma",
+				     "nvidia,tegra186-gpcdma";
 			reg = <0x2600000 0x210000>;
 			resets = <&bpmp TEGRA234_RESET_GPCDMA>;
 			reset-names = "gpcdma";
-- 
2.17.1

Re: [PATCH v4 1/3] dt-bindings: dmaengine: Add compatible for Tegra234

[Rob Herring]

On Wed, 20 Jul 2022 16:10:43 +0530, Akhil R wrote:
> Document the compatible string used by GPCDMA controller for Tegra234.
> 
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
> ---
>  .../devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml      | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v4 0/3] Add compatible for Tegra234 GPCDMA

[Vinod Koul]

On 20-07-22, 16:10, Akhil R wrote:
> In cases where the client bus gets corrupted or if the end device
> ceases to send/receive data, the DMA could wait for the data forever.
> Tegra234 supports recovery of such channels hung in flush mode.
> 
> Add a separate compatible for Tegra234 so that this scenario can be
> handled in the driver.

Applied 1-2, thanks

-- 
~Vinod