Messages in this thread | | | Date | Thu, 7 Jul 2022 11:40:02 +0100 | Subject | Re: [PATCH 1/2] dmaengine: tegra: Add terminate() for Tegra234 | From | Jon Hunter <> |
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On 07/07/2022 11:27, Akhil R wrote: > 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() and disables the channel. > > Signed-off-by: Akhil R <akhilrajeev@nvidia.com> > --- > arch/arm64/boot/dts/nvidia/tegra234.dtsi | 5 +++-- > drivers/dma/tegra186-gpc-dma.c | 26 ++++++++++++++++++++++-- > 2 files changed, 27 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/boot/dts/nvidia/tegra234.dtsi b/arch/arm64/boot/dts/nvidia/tegra234.dtsi > index cf611eff7f6b..83d1ad7d3c8c 100644 > --- a/arch/arm64/boot/dts/nvidia/tegra234.dtsi > +++ b/arch/arm64/boot/dts/nvidia/tegra234.dtsi > @@ -22,8 +22,9 @@ > ranges = <0x0 0x0 0x0 0x40000000>; > > gpcdma: dma-controller@2600000 { > - compatible = "nvidia,tegra194-gpcdma", > - "nvidia,tegra186-gpcdma"; > + compatible = "nvidia,tegra234-gpcdma", > + "nvidia,tegra194-gpcdma", > + "nvidia,tegra186-gpcdma"; > reg = <0x2600000 0x210000>; > resets = <&bpmp TEGRA234_RESET_GPCDMA>; > reset-names = "gpcdma";
I think that this should be split into two patches.
> 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; > +}
The commit message says that "add a new terminate() function that ignores the outcome of dma_pause() and disables the channel". But I only see pause being done here.
> + > 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, > }, { > }, > };
-- nvpublic
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