mmc: dw_mmc: insmod followed by rmmod will hung for eMMC

Remove module of dw_mmc driver will hung for eMMC devices if we follow the
steps which are listed below,
	insmod dw_mmc.ko
	insmod dw_mmc-pci.ko
	rmmod dw_mmc-pci.ko

The root cause for this issue is, dw_mci_remove() will disable all the
interrupts by programming 0x0 to INTMASK register then it will call
dw_mci_cleanup_slot(). But dw_mci_cleanup_slot() is issuing CMD6 to
disable the eMMC boot partition and it is waiting for Command Complete
interrupt. Since INTMASK was already cleared by dw_mci_remove(), Command
Complete interrupt is not reaching the system. This leads to process hung.

Signed-off-by: Prabu Thangamuthu <prabu.t@synopsys.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 55179f1..40e9d8e 100644 (file)
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2926,15 +2926,15 @@ void dw_mci_remove(struct dw_mci *host)
 {
        int i;
 
-       mci_writel(host, RINTSTS, 0xFFFFFFFF);
-       mci_writel(host, INTMASK, 0); /* disable all mmc interrupt first */
-
        for (i = 0; i < host->num_slots; i++) {
                dev_dbg(host->dev, "remove slot %d\n", i);
                if (host->slot[i])
                        dw_mci_cleanup_slot(host->slot[i], i);
        }
 
+       mci_writel(host, RINTSTS, 0xFFFFFFFF);
+       mci_writel(host, INTMASK, 0); /* disable all mmc interrupt first */
+
        /* disable clock to CIU */
        mci_writel(host, CLKENA, 0);
        mci_writel(host, CLKSRC, 0);