On Thu, Dec 31, 2020 at 5:04 PM Bin Meng <bmeng...@gmail.com> wrote:
>
> From: Bin Meng <bin.m...@windriver.com>
>
> commit f6fb1f9b319f ("sdcard: Correct CRC16 offset in sd_function_switch()")
> changed the 16-bit CRC to be stored at offset 64. In fact, this CRC
> calculation is completely wrong. From the original codes, it wants
> to calculate the CRC16 of the first 64 bytes of sd->data[], however
> passing 64 as the `width` to sd_crc16() actually counts 256 bytes
> starting from the `message` for the CRC16 calculation, which is not
> what we want.
>
> Besides that, it seems exisitng sd_crc16() algorithm does not match
> the SD spec, which says CRC16 is the CCITT one but the calculation
> does not produce expected result. It turns out the CRC16 was never
> transfered outside the sd core, as in sd_read_byte() we see:
>
> if (sd->data_offset >= 64)
> sd->state = sd_transfer_state;
>
> Given above reaons, let's drop it.
>
> Signed-off-by: Bin Meng <bin.m...@windriver.com>
> ---
>
> hw/sd/sd.c | 18 ------------------
> 1 file changed, 18 deletions(-)
Reviewed-by: Pragnesh Patel <pragnesh.pa...@sifive.com>
Tested-by: Pragnesh Patel <pragnesh.pa...@sifive.com>
