On 22/04/16 15:14, Shardar Shariff Md wrote:
> Initialize default channel slave_id(req_sel) to invalid id
> (i.e max supported slave id + 1) to avoid overwriting of slave_id
> during tegra_dma_slave_config() with client data if slave_id
> is not initialized through DT
>
> Signed-off-by: Shardar Shariff Md <smohammed@xxxxxxxxxx>
>
> ---
> Changes from v1:
> - Instead of initializing the slave id to -1 define macros for
> max slave id and invalid slave id and do the checks accordingly.
>
> Changes from v2:
> - Check slave id boundary before dma channel is allocated to
> avoid channel leakage.
> ---
> drivers/dma/tegra20-apb-dma.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 3871f29..f57cee85 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -54,6 +54,7 @@
> #define TEGRA_APBDMA_CSR_ONCE BIT(27)
> #define TEGRA_APBDMA_CSR_FLOW BIT(21)
> #define TEGRA_APBDMA_CSR_REQ_SEL_SHIFT 16
> +#define TEGRA_APBDMA_CSR_REQ_SEL_MASK 0x1F
> #define TEGRA_APBDMA_CSR_WCOUNT_MASK 0xFFFC
>
> /* STATUS register */
> @@ -114,6 +115,9 @@
> /* Channel base address offset from APBDMA base address */
> #define TEGRA_APBDMA_CHANNEL_BASE_ADD_OFFSET 0x1000
>
> +#define TEGRA_APBDMA_SLAVE_ID_MAX TEGRA_APBDMA_CSR_REQ_SEL_MASK
> +#define TEGRA_APBDMA_SLAVE_ID_INVALID (TEGRA_APBDMA_SLAVE_ID_MAX + 1)
> +
> struct tegra_dma;
>
> /*
> @@ -353,7 +357,7 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
> }
>
> memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
> - if (!tdc->slave_id)
> + if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID)
> tdc->slave_id = sconfig->slave_id;
I think we still need to check sconfig->slave_id is less than the MAX here.
> tdc->config_init = true;
> return 0;
> @@ -1236,7 +1240,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
> }
> pm_runtime_put(tdma->dev);
>
> - tdc->slave_id = 0;
> + tdc->slave_id = TEGRA_APBDMA_SLAVE_ID_INVALID;
> }
>
> static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
> @@ -1245,13 +1249,20 @@ static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
> struct tegra_dma *tdma = ofdma->of_dma_data;
> struct dma_chan *chan;
> struct tegra_dma_channel *tdc;
> + unsigned int slave_id;
We don't need this definition.
> +
> + slave_id = dma_spec->args[0];
> + if (slave_id > TEGRA_APBDMA_SLAVE_ID_MAX) {
Use dma_spec->args[0] here directly.
> + dev_err(tdma->dev, "Invalid slave id: %d\n", slave_id);
And here.
Cheers
Jon
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