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+rene...@sang-engineering.com>

Reviewed-by: Simon Horman <horms+rene...@verge.net.au>

> ---
>  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
> 

Reply via email to