Re: [PATCH v4 2/2] dmaengine: tegra210-adma: check for adma max page

[Jon Hunter]

On 05/02/2025 03:31, Mohan Kumar D wrote:
> Have additional check for max channel page during the probe
> to cover if any offset overshoot happens due to wrong DT
> configuration.
>
> Fixes: 68811c928f88 ("dmaengine: tegra210-adma: Support channel page")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Mohan Kumar D <mkumard@xxxxxxxxxx>
> ---
>   drivers/dma/tegra210-adma.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
> index a0bd4822ed80..801740ad8e0d 100644
> --- a/drivers/dma/tegra210-adma.c
> +++ b/drivers/dma/tegra210-adma.c
> @@ -83,7 +83,9 @@ struct tegra_adma;
>    * @nr_channels: Number of DMA channels available.
>    * @ch_fifo_size_mask: Mask for FIFO size field.
>    * @sreq_index_offset: Slave channel index offset.
> + * @max_page: Maximum ADMA Channel Page.
>    * @has_outstanding_reqs: If DMA channel can have outstanding requests.
> + * @set_global_pg_config: Global page programming.
>    */
>   struct tegra_adma_chip_data {
>   	unsigned int (*adma_get_burst_config)(unsigned int burst_size);
> @@ -99,6 +101,7 @@ struct tegra_adma_chip_data {
>   	unsigned int nr_channels;
>   	unsigned int ch_fifo_size_mask;
>   	unsigned int sreq_index_offset;
> +	unsigned int max_page;
>   	bool has_outstanding_reqs;
>   	void (*set_global_pg_config)(struct tegra_adma *tdma);
>   };
> @@ -854,6 +857,7 @@ static const struct tegra_adma_chip_data tegra210_chip_data = {
>   	.nr_channels		= 22,
>   	.ch_fifo_size_mask	= 0xf,
>   	.sreq_index_offset	= 2,
> +	.max_page		= 0,
>   	.has_outstanding_reqs	= false,
>   	.set_global_pg_config	= NULL,
>   };
> @@ -871,6 +875,7 @@ static const struct tegra_adma_chip_data tegra186_chip_data = {
>   	.nr_channels		= 32,
>   	.ch_fifo_size_mask	= 0x1f,
>   	.sreq_index_offset	= 4,
> +	.max_page		= 4,
>   	.has_outstanding_reqs	= true,
>   	.set_global_pg_config	= tegra186_adma_global_page_config,
>   };
> @@ -921,7 +926,7 @@ static int tegra_adma_probe(struct platform_device *pdev)
>   			page_offset = res_page->start - res_base->start;
>   			page_no = div_u64(page_offset, cdata->ch_base_offset);
>   
> -			if (WARN_ON(page_no == 0))
> +			if (WARN_ON(page_no == 0 || page_no > cdata->max_page))

So no one should ever specify the 'page' region for Tegra210, correct? 
If they did then this would always fail. I don't know if it is also 
worth checking if someone has a 'page' region for a device that has 
max_page == 0?

Jon
--
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