On Mon, Aug 11, 2014 at 04:32:16PM +0800, rogerable@xxxxxxxxxxx wrote:
> From: Roger Tseng <rogerable@xxxxxxxxxxx>
>
> Current code erroneously fill the last byte of R2 response with an undefined
> value. In addition, it is impossible to obtain the real values since the
> controller actually 'offloads' the last byte(CRC7, end bit) while receiving R2
> response. This could cause mmc stack to obtain inconsistent CID from the same
> card after resume and misidentify it as a different card.
>
> Fix by assigning a dummy value 0x01 to the last byte of R2 response.
>
> Signed-off-by: Roger Tseng <rogerable@xxxxxxxxxxx>
> ---
> drivers/mmc/host/rtsx_pci_sdmmc.c | 1 +
> drivers/mmc/host/rtsx_usb_sdmmc.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index dfde4a2..54849d8 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -412,6 +412,7 @@ static void sd_send_cmd_get_rsp(struct realtek_pci_sdmmc *host,
> }
>
> if (rsp_type == SD_RSP_TYPE_R2) {
> + ptr[16] = 1;
Avoid magic numbers like 16 and 0x1.
This is subtle enough that it deserves a comment.
ptr[stat_idx] = 0x1 /* 0x1 chosen randomly */
> for (i = 0; i < 4; i++) {
> cmd->resp[i] = get_unaligned_be32(ptr + 1 + i * 4);
> dev_dbg(sdmmc_dev(host), "cmd->resp[%d] = 0x%08x\n",
There are a lot of magic numbers in this function. We could get rid
of this i < 4 loop but doing:
memcpy(cmd->resp, ptr + 1, resp_len);
Currently we don't use resp_len and the resp_len = 5 assignment is off
by one... It should be resp_len = 4. This function is quite ugly.
regards,
dan carpenter
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