[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Heiko Schocher]

Hello Gong Qianyu,

added Stefano Babic to cc as he is the imx maintainer.

Am 18.12.2015 um 10:38 schrieb Gong Qianyu:
> This could avoid executing the code that only applies to i.MX platforms.
>
> The bus_i2c_init() is called before relocation and will assgin value
> to a static variable. If U-Boot is then still running in a flash
> device, it's theoretically not allowed to write data to flash without
> an erasing operation. For i.MX platforms, the U-Boot is always running
> in DDR.
>
> Actually it causes asynchronous error when the ARM64 system error
> report is enabled and the flash write protect is set.
>
> Signed-off-by: Gong Qianyu <Qianyu.Gong at freescale.com>
> ---
> V3:
>   - Sorry..Remove an unrelated line in other file.
>
>   drivers/i2c/mxc_i2c.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)

Ok, from my side, but it would be better to switch your board(s)
to support DM and get rid of this old stuff from this driver.

Reviewed-by: Heiko Schocher <hs at denx.de>

bye,
Heiko
>
> diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
> index fa4c82f..b2d15c9 100644
> --- a/drivers/i2c/mxc_i2c.c
> +++ b/drivers/i2c/mxc_i2c.c
> @@ -581,8 +581,16 @@ void bus_i2c_init(int index, int speed, int unused,
>   		return;
>   	}
>
> -	mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> -	mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> +	/*
> +	 * Warning: Be careful to allow the assignment to a static
> +	 * variable here. This function could be called while U-Boot is
> +	 * still running in flash memory. So such assignment is equal
> +	 * to write data to flash without erasing.
> +	 */
> +	if (idle_bus_fn)
> +		mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> +	if (idle_bus_data)
> +		mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
>
>   	ret = enable_i2c_clk(1, index);
>   	if (ret < 0) {
>

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