From 6f67cc6fd1cf339a0f19b9d4a998ec3c0123b1b6 Mon Sep 17 00:00:00 2001 From: Roger Tseng Date: Fri, 15 Aug 2014 14:06:01 +0800 Subject: [PATCH] mmc: rtsx_usb_sdmmc: fix incorrect last byte in R2 response Current code erroneously fill the last byte of R2 response with an undefined value. In addition, the controller actually 'offloads' the last byte (CRC7, end bit) while receiving R2 response and thus it's impossible to get the actual value. 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 dummy CRC and end bit: {7'b0, 1} = 0x1 to the last byte of R2. Cc: # v3.16+ Fixes: c7f6558d84af ("mmc: Add realtek USB sdmmc host driver") Signed-off-by: Roger Tseng Signed-off-by: Ulf Hansson --- drivers/mmc/host/rtsx_usb_sdmmc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c index 5d3766e..d9153a7 100644 --- a/drivers/mmc/host/rtsx_usb_sdmmc.c +++ b/drivers/mmc/host/rtsx_usb_sdmmc.c @@ -435,6 +435,13 @@ static void sd_send_cmd_get_rsp(struct rtsx_usb_sdmmc *host, } if (rsp_type == SD_RSP_TYPE_R2) { + /* + * The controller offloads the last byte {CRC-7, end bit 1'b1} + * of response type R2. Assign dummy CRC, 0, and end bit to the + * byte(ptr[16], goes into the LSB of resp[3] later). + */ + ptr[16] = 1; + 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", -- 2.7.4