Hi Wolfgang,
On Mon, Mar 4, 2013 at 7:21 PM, Wolfgang Denk wd@denx.de wrote:
Dear Sonic Zhang,
In message CAJxxZ0O_OZk7w_CDfJkzPwDMFqwT1m-Yn_Bz6yzHRDFqT6wrBw@mail.gmail.com you wrote:
Maybe I didn't describe it clearly. Yes, I return 0 at the end of this function. But, the same function may return UNUSABLE_ERR(-17) at the beginning if the data flags match MMC_DATA_WRITE. That's why the function can't return void. Is anything contradicting in my explanation?
I see. Sorry, I missed that other return.
One additional question, though:
/* kick off transfer */ bfin_write_SDH_DATA_CTL(bfin_read_SDH_DATA_CTL() | DTX_DMA_E | DTX_E);
return ret;
return 0;Are the bfin_read_SDH_DATA_CTL() and bfin_write_SDH_DATA_CTL() supposed to always work, i. e. are we positively sure that these can never fail, so there is no need to test the return code and handle error conditions?
Yes, bfin_write_XXX and bfin_read_XXX are simply defined as memory access operations. They either succeed or cause hardware error exception.
#define bfin_read_SDH_DATA_CTL() bfin_read16(SDH_DATA_CTL) #define _bfin_readX(addr, size, asm_size, asm_ext) ({ \ u32 __v; \ __asm__ __volatile__( \ "%0 = " #asm_size "[%1]" #asm_ext ";" \ : "=d" (__v) \ : "a" (addr) \ ); \ __v; })
Regards,
Sonic