Hi Chris,
On Tue, Jul 11, 2017 at 9:37 PM, Chris Brandt <Chris.Brandt@xxxxxxxxxxx> wrote:
> On Tuesday, July 11, 2017, Geert Uytterhoeven wrote:
>> > zeroing out the bottom 2 bits of count for out math.
>>
>> s/out/our/
>
> Thank you!
>
>> > - buf8 = (u8 *)(buf + (count >> 2));
>> > + buf8 = (u8 *)buf + (count & ~3);
>> > count %= 4;
>>
>> While correct, this is IMHO still difficult to understand for the casual
>> reader.
>>
>> Given the code before casts to "u32 *", and uses "count >>2", and the code
>> after also casts to "u32 *", what about getting rid of all casts like:
>>
>> u32 data = 0;
>> u32 *buf32 = buf;
>>
>> if (is_read)
>> sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, buf32,
>> count >> 2);
>> else
>> sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, buf32,
>> count >> 2);
>>
>> /* if count was multiple of 4 */
>> if (!(count & 0x3))
>> return;
>>
>> buf32 += count >> 2;
>> count %= 4;
>>
>> if (is_read) {
>> sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, &data, 1);
>> memcpy(buf32, &data, count);
>> } else {
>> memcpy(&data, buf32, count);
>> sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, &data, 1);
>> }
>>
>> return;
>> }
>>
>
> Good idea. I just tried it and it seems to work. I'll resend a patch.
>
>
>> u32 *buf32 = buf;
>
> GCC didn't like this line without casting buf to a u32 *. It threw an
> error, not just a warning. Go figure.
Sorry, the cast is indeed missing, as buf is not a void *.
> Question:
>> u32 data = 0;
>
> Any special reason why you are initializing this to 0????
I think the original code did that, too. Hmm, I got mislead by the curly braces,
there's no "0" in between them.
It's also a bit safer to not write uninitialized data to the CTL_SD_DATA_PORT
register.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
