[U-Boot] [PATCH 1/1] arm: sunxi: Add NULL pointer check

[Stefan Mavrodiev]

On 12/5/18 5:46 PM, Maxime Ripard wrote:
> On Wed, Dec 05, 2018 at 02:27:57PM +0200, Stefan Mavrodiev wrote:
>> Current driver doesn't check if the destination pointer is NULL.
>> This cause the data from the FIFO to be stored inside the internal
>> SDRAM ( address 0 ).
>>
>> The patch add simple check if the destination pointer is NULL.
>>
>> Signed-off-by: Stefan Mavrodiev <stefan at olimex.com>
>> ---
>>   drivers/spi/sun4i_spi.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/spi/sun4i_spi.c b/drivers/spi/sun4i_spi.c
>> index b86b5a00ad..38cc743c61 100644
>> --- a/drivers/spi/sun4i_spi.c
>> +++ b/drivers/spi/sun4i_spi.c
>> @@ -129,7 +129,8 @@ static inline void sun4i_spi_drain_fifo(struct sun4i_spi_priv *priv, int len)
>>   
>>   	while (len--) {
>>   		byte = readb(&priv->regs->rxdata);
>> -		*priv->rx_buf++ = byte;
>> +		if (priv->rx_buf)
>> +			*priv->rx_buf++ = byte;
> It seems pretty inefficient to test the pointer at each access, it
> would be better to check it once before starting the transfer.
>
> I'm not sure if that can even happen?

I've tried to check that before draining the receive fifo, but then the 
controller doesn't
work. I'm thinking that the fifo must be drained in any case.

>
> Maxime
>