[PATCH v2] mmc: dw_mmc: insmod followed by rmmod will hung for eMMC

[PATCH v2] mmc: dw_mmc: insmod followed by rmmod will hung for eMMC

[Prabu Thangamuthu]

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>
---
Change log v2:
	-Added prefix "mmc:" to the commit message header.
	-Updated the Commit Message.

 drivers/mmc/host/dw_mmc.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 55179f1..40e9d8e 100644
--- 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);
-- 
1.7.6.5

Re: [PATCH v2] mmc: dw_mmc: insmod followed by rmmod will hung for eMMC

[Jaehoon Chung]

Hi, Prabu.

Thanks for resending the patch.
Will apply this patch at my tree.

Thanks!

Best Regards,
Jaehoon Chung

On 05/28/2015 09:21 PM, Prabu Thangamuthu wrote:
> 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>
> ---
> Change log v2:
> 	-Added prefix "mmc:" to the commit message header.
> 	-Updated the Commit Message.
> 
>  drivers/mmc/host/dw_mmc.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 55179f1..40e9d8e 100644
> --- 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);
>