mmc: omap_hsmmc: clear status flags before starting a new command

Commit 1f6b9fa40e76fffaaa0b3bd6a0bfdcf1cdc06efa consolidated writes to the STAT register in one location, moving them from omap_hsmmc_do_irq() to omap_hsmmc_irq(). This move has the unwanted side effect that the controller status flags are potentially cleared after a new command has been started as a consequence of reading the previous status flags. This means that if the new command changes the status flags before the IRQ routine returns, those flags may be cleared without handling the event which asserted them, and thus missing the event.
Move the writing of the STAT register back in omap_hsmmc_do_irq(), before handling the status flags which generated the interrupt.

Signed-off-by Francesco Lavra <[email protected]>

---
 drivers/mmc/host/omap_hsmmc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

drivers/mmc/host/omap_hsmmc.c +1 -0

index eccedc7..301cb7e 100644
@@ -1041,6 +1041,7 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
 		}
 	}
 
+	OMAP_HSMMC_WRITE(host->base, STAT, status);
 	if (end_cmd || ((status & CC_EN) && host->cmd))
 		omap_hsmmc_cmd_done(host, host->cmd);
 	if ((end_trans || (status & TC_EN)) && host->mrq)

Commit 1f6b9fa40e76fffaaa0b3bd6a0bfdcf1cdc06efa consolidated writes to the STAT register in one location, moving them from omap_hsmmc_do_irq() to omap_hsmmc_irq(). This move has the unwanted side effect that the controller status flags are potentially cleared after a new command has been started as a consequence of reading the previous status flags. This means that if the new command changes the status flags before the IRQ routine returns, those flags may be cleared without handling the event which asserted them, and thus missing the event.
Move the writing of the STAT register back in omap_hsmmc_do_irq(), before handling the status flags which generated the interrupt.

Signed-off-by Francesco Lavra <[email protected]>

---
  drivers/mmc/host/omap_hsmmc.c |    2 +-
  1 files changed, 1 insertions(+), 1 deletions(-)

drivers/mmc/host/omap_hsmmc.c +1 -1

index eccedc7..301cb7e 100644
@@ -1041,6 +1041,7 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
  		}
  	}
 
+	OMAP_HSMMC_WRITE(host->base, STAT, status);
  	if (end_cmd || ((status & CC_EN) && host->cmd))
  		omap_hsmmc_cmd_done(host, host->cmd);
  	if ((end_trans || (status & TC_EN)) && host->mrq)

@@ -1060,7 +1061,6 @@ static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
  		omap_hsmmc_do_irq(host, status);
 
  		/* Flush posted write */
-		OMAP_HSMMC_WRITE(host->base, STAT, status);
  		status = OMAP_HSMMC_READ(host->base, STAT);
  	}
 

Quoted 11 lines · Francesco Lavra

Commit 1f6b9fa40e76fffaaa0b3bd6a0bfdcf1cdc06efa consolidated writes to the STAT register in one location, moving them from omap_hsmmc_do_irq() to omap_hsmmc_irq(). This move has the unwanted side effect that the controller status flags are potentially cleared after a new command has been started as a consequence of reading the previous status flags. This means that if the new command changes the status flags before the IRQ routine returns, those flags may be cleared without handling the event which asserted them, and thus missing the event.
Move the writing of the STAT register back in omap_hsmmc_do_irq(), before handling the status flags which generated the interrupt.

Quoted 1 line

Signed-off-by Francesco Lavra <[email protected]>

Reviewed and Tested-by: Balaji T K <[email protected]>