On Tue, Mar 05, 2019 at 06:54:32PM +0100, Wolfram Sang wrote:
> Use a macro for the hardcoded value and apply a build check. If it is
> not met, the driver logic will not work anymore.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-rcar.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
> index 3ce74edcd70c..925858915569 100644
> --- a/drivers/i2c/busses/i2c-rcar.c
> +++ b/drivers/i2c/busses/i2c-rcar.c
> @@ -85,6 +85,7 @@
> /* ICFBSCR */
> #define TCYC17 0x0f /* 17*Tcyc delay 1st bit between SDA and SCL */
>
> +#define RCAR_MIN_DMA_LEN 8
>
> #define RCAR_BUS_PHASE_START (MDBS | MIE | ESG)
> #define RCAR_BUS_PHASE_DATA (MDBS | MIE)
> @@ -412,8 +413,8 @@ static void rcar_i2c_dma(struct rcar_i2c_priv *priv)
> int len;
>
> /* Do various checks to see if DMA is feasible at all */
> - if (IS_ERR(chan) || msg->len < 8 || !(msg->flags & I2C_M_DMA_SAFE) ||
> - (read && priv->flags & ID_P_NO_RXDMA))
> + if (IS_ERR(chan) || msg->len < RCAR_MIN_DMA_LEN ||
> + !(msg->flags & I2C_M_DMA_SAFE) || (read && priv->flags & ID_P_NO_RXDMA))
> return;
>
> if (read) {
> @@ -921,6 +922,9 @@ static int rcar_i2c_probe(struct platform_device *pdev)
> struct i2c_timings i2c_t;
> int irq, ret;
>
> + /* Otherwise logic will break because some bytes must always use PIO */
> + BUILD_BUG_ON_MSG(RCAR_MIN_DMA_LEN < 3, "Invalid min DMA length");
> +
> priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
> --
> 2.11.0
>
