[PATCH v4.4.y] mmc: tmio_mmc_core: don't claim spurious interrupts

[PATCH v4.4.y] mmc: tmio_mmc_core: don't claim spurious interrupts

[Sergei Shtylyov]

Commit 5c27ff5db1491a947264d6d4e4cbe43ae6535bae upstream.

I have encountered an interrupt storm during the eMMC chip probing (and
the chip finally didn't get detected).  It turned out that U-Boot left
the DMAC interrupts enabled while the Linux driver  didn't use those.
The SDHI driver's interrupt handler somehow assumes that, even if an
SDIO interrupt didn't happen, it should return IRQ_HANDLED.  I think
that if none of the enabled interrupts happened and got handled, we
should return IRQ_NONE -- that way the kernel IRQ code recoginizes
a spurious interrupt and masks it off pretty quickly...

Fixes: 7729c7a232a9 ("mmc: tmio: Provide separate interrupt handlers")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

---
The patch is against the 'linux-4.4.y' branch of the -stable repo.

 drivers/mmc/host/tmio_mmc_pio.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Index: linux-stable/drivers/mmc/host/tmio_mmc_pio.c
===================================================================
--- linux-stable.orig/drivers/mmc/host/tmio_mmc_pio.c
+++ linux-stable/drivers/mmc/host/tmio_mmc_pio.c
@@ -716,7 +716,7 @@ irqreturn_t tmio_mmc_sdio_irq(int irq, v
 	unsigned int sdio_status;
 
 	if (!(pdata->flags & TMIO_MMC_SDIO_IRQ))
-		return IRQ_HANDLED;
+		return IRQ_NONE;
 
 	status = sd_ctrl_read16(host, CTL_SDIO_STATUS);
 	ireg = status & TMIO_SDIO_MASK_ALL & ~host->sdcard_irq_mask;
@@ -730,7 +730,7 @@ irqreturn_t tmio_mmc_sdio_irq(int irq, v
 	if (mmc->caps & MMC_CAP_SDIO_IRQ && ireg & TMIO_SDIO_STAT_IOIRQ)
 		mmc_signal_sdio_irq(mmc);
 
-	return IRQ_HANDLED;
+	return IRQ_RETVAL(ireg);
 }
 EXPORT_SYMBOL(tmio_mmc_sdio_irq);
 
@@ -747,9 +747,7 @@ irqreturn_t tmio_mmc_irq(int irq, void *
 	if (__tmio_mmc_sdcard_irq(host, ireg, status))
 		return IRQ_HANDLED;
 
-	tmio_mmc_sdio_irq(irq, devid);
-
-	return IRQ_HANDLED;
+	return tmio_mmc_sdio_irq(irq, devid);
 }
 EXPORT_SYMBOL(tmio_mmc_irq);
 

Re: [PATCH v4.4.y] mmc: tmio_mmc_core: don't claim spurious interrupts

[GregKH]

On Sun, Mar 24, 2019 at 08:32:12PM +0300, Sergei Shtylyov wrote:
> Commit 5c27ff5db1491a947264d6d4e4cbe43ae6535bae upstream.
> 
> I have encountered an interrupt storm during the eMMC chip probing (and
> the chip finally didn't get detected).  It turned out that U-Boot left
> the DMAC interrupts enabled while the Linux driver  didn't use those.
> The SDHI driver's interrupt handler somehow assumes that, even if an
> SDIO interrupt didn't happen, it should return IRQ_HANDLED.  I think
> that if none of the enabled interrupts happened and got handled, we
> should return IRQ_NONE -- that way the kernel IRQ code recoginizes
> a spurious interrupt and masks it off pretty quickly...
> 
> Fixes: 7729c7a232a9 ("mmc: tmio: Provide separate interrupt handlers")
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> 
> ---
> The patch is against the 'linux-4.4.y' branch of the -stable repo.

Now queued up, thanks!

greg k-h