Messages in this thread | | | Date | Fri, 23 Sep 2022 11:50:30 +0100 | Subject | Re: [PATCH v2 3/3] dmaengine: tegra: Add support for dma-channel-mask | From | Jon Hunter <> |
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On 23/09/2022 11:17, Akhil R wrote: >> On 19/09/2022 12:25, Akhil R wrote: >>> Add support for dma-channel-mask so that only the specified channels >>> are used. This helps to reserve some channels for the firmware. >>> >>> This was initially achieved by limiting the channel number to 31 in >>> the driver and adjusting the register address to skip channel0 which >>> was reserved for a firmware. Now, with this change, the driver can >>> align more to the actual hardware which has 32 channels. >>> >>> Signed-off-by: Akhil R <akhilrajeev@nvidia.com> >>> --- >>> drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++------- >>> 1 file changed, 30 insertions(+), 7 deletions(-) >>> >>> diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc- >> dma.c >>> index fa9bda4a2bc6..1d1180db6d4e 100644 >>> --- a/drivers/dma/tegra186-gpc-dma.c >>> +++ b/drivers/dma/tegra186-gpc-dma.c >>> @@ -161,7 +161,10 @@ >>> #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 >>> +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000 >> >> Why did this value change? There is no mention in the commit message. If >> this was incorrect before, then this needs to be a separate patch and >> tagged with the appropriate fixes tag so that this can be picked up for >> stable. > This is mentioned in the commit message. > > "... and adjusting the register address to skip channel0 ..." > > Probably it is not very clear that it directs to this change. Shall I update the > commit message to have a clearer context?
Ah OK. I was wondering how this worked with 'channel_reg_size' but looking closer I see channel_reg_size is always SZ_64K. I wonder why we even bother having this parameter and don't use SZ_64K directly?
Anyway, for now this is fine.
Jon
-- nvpublic
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