On some boards with broken card detection if eMMC card is not present system hangs during mmc_rescan. The sequence is as below: mmc_rescan_try_freq:sdio_reset: > send CMD52 < irq with SDMMC_INT_RESP_ERR and SDMMC_STATUS_BUSY < irq with SDMMC_INT_CMD_DONE and SDMMC_STATUS_BUSY > dw_mci_wait_busy:dw_mci_ctrl_reset < irq with SDMMC_INT_RESP_ERR | SDMMC_INT_CMD_DONE and status not busy > send CMD52 ... mmc_rescan waits infinitely for irq in mmc_wait_for_req
It seems hardware enters into some strange state after issuing CMD52 to non-existing card. It stops signaling IRQs and it can even hang on accessing some registers, for example UHS_REG or CTYPE. The patch tries to solve it by resetting the controller and marking card as removed, as a result no further commands will be issued until next rescan. The issue has been observed on Odroid-XU3 boards (Exynos5422 with dw_mmc 250A). Signed-off-by: Andrzej Hajda <a.ha...@samsung.com> --- Hi, I am not familiar with MMC internals so please verify patch (in-)sanity. Especially I am not sure if (SDMMC_INT_RESP_ERR | SDMMC_INT_CMD_DONE with status busy) occurs only in this situation, if no, more precise check should be added, I guess. Or maybe it should be a quirk??? The patch is based on Addy's 'about data busy' patchset [1]. Alim's advice about stabilization of host voltage has been tested also, without success [2]. [1]: http://permalink.gmane.org/gmane.linux.kernel/1888161 [2]: http://permalink.gmane.org/gmane.linux.kernel.mmc/31202 Regards Andrzej --- drivers/mmc/host/dw_mmc.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 692d97a..3cba1eb 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -2182,8 +2182,19 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) } if (pending & SDMMC_INT_CMD_DONE) { + u32 err = (pending | host->cmd_status) & + SDMMC_INT_RESP_ERR; + struct dw_mci_slot *slot = host->cur_slot; + mci_writel(host, RINTSTS, SDMMC_INT_CMD_DONE); - dw_mci_cmd_interrupt(host, pending); + if (err && dw_mci_card_busy(slot->mmc)) { + u32 ctrl = mci_readl(host, CTRL); + + ctrl |= SDMMC_CTRL_ALL_RESET_FLAGS; + mci_writel(host, CTRL, ctrl); + clear_bit(DW_MMC_CARD_PRESENT, &slot->flags); + } else + dw_mci_cmd_interrupt(host, pending); } if (pending & SDMMC_INT_CD) { -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
