emmc的时机

Question

当我移植三星的s5p6818系统时，出现以下错误。关键字是

CRC ERROR CMD.25 
mmcblk0: response CRC error sending r/w cmd command, card status 0x900.

我分析了

linux/kernel/kernel-3.4.39/ After drivers/mmc/host/dw_mmc.c


if (status & DW_MCI_DATA_ERROR_FLAGS) {
                if (status & SDMMC_INT_DTO) {
                    data->error = -ETIMEDOUT;
                } else if (status & SDMMC_INT_DCRC) {
                    data->error = -EILSEQ;
                    printk("CRC ERROR CMD.%d\n", host->mrq->cmd->opcode);
                    /* Retry write, jhkim */
                    if (host->mrq && host->mrq->cmd && (
                        host->mrq->cmd->opcode == MMC_WRITE_BLOCK ||
                        host->mrq->cmd->opcode == MMC_WRITE_MULTIPLE_BLOCK)
                        )
                        host->mrq->cmd->error = -EILSEQ;

发现emmc的时间有问题，所以我改变了

linux/kernel/kernel-3.4.39/arch/arm/plat-s5p6818/drone/device.c