On 08/11/2014 09:02 PM, Dan Carpenter wrote:
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 */
The 0x1 consists of 7-bit dummy zero CRC and stop bit 1, described in SD
card. Anyway, I'll give a comment to this in the next version.
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.
I can remove the unused rsp_len in this function. But I'm afraid the
loop is still required. The destination cmd->resp is cpu-endian, but the
raw response from SD card in the buffer (pointed by ptr) is big-endian.
regards,
dan carpenter
------Please consider the environment before printing this e-mail.
.
Best regards,
Roger Tseng
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