mmc: at91_mci: avoid timeouts

The at91 mci controller internal state machine seems to often crash. This can
be fixed by resetting the controller after each command for at91rm9200 and by
setting the MCI_BLKR register on at91sam926*.

Signed-off-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Hans J Koch <hjk@linutronix.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index fce171c7c67e..e9242110ce2e 100644
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -130,6 +130,43 @@ struct at91mci_host
 	struct timer_list timer;
 };
 
+/*
+ * Reset the controller and restore most of the state
+ */
+static void at91_reset_host(struct at91mci_host *host)
+{
+	unsigned long flags;
+	u32 mr;
+	u32 sdcr;
+	u32 dtor;
+	u32 imr;
+
+	local_irq_save(flags);
+	imr = at91_mci_read(host, AT91_MCI_IMR);
+
+	at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);
+
+	/* save current state */
+	mr = at91_mci_read(host, AT91_MCI_MR) & 0x7fff;
+	sdcr = at91_mci_read(host, AT91_MCI_SDCR);
+	dtor = at91_mci_read(host, AT91_MCI_DTOR);
+
+	/* reset the controller */
+	at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIDIS | AT91_MCI_SWRST);
+
+	/* restore state */
+	at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIEN);
+	at91_mci_write(host, AT91_MCI_MR, mr);
+	at91_mci_write(host, AT91_MCI_SDCR, sdcr);
+	at91_mci_write(host, AT91_MCI_DTOR, dtor);
+	at91_mci_write(host, AT91_MCI_IER, imr);
+
+	/* make sure sdio interrupts will fire */
+	at91_mci_read(host, AT91_MCI_SR);
+
+	local_irq_restore(flags);
+}
+
 static void at91_timeout_timer(unsigned long data)
 {
 	struct at91mci_host *host;
@@ -148,6 +185,7 @@ static void at91_timeout_timer(unsigned long data)
 				host->request->cmd->error = -ETIMEDOUT;
 		}
 
+		at91_reset_host(host);
 		mmc_request_done(host->mmc, host->request);
 	}
 }
@@ -512,6 +550,11 @@ static void at91_mci_send_command(struct at91mci_host *host, struct mmc_command
 		mr |= AT91_MCI_PDCMODE;
 		at91_mci_write(host, AT91_MCI_MR, mr);
 
+		if (!cpu_is_at91rm9200())
+			at91_mci_write(host, AT91_MCI_BLKR,
+				AT91_MCI_BLKR_BCNT(blocks) |
+				AT91_MCI_BLKR_BLKLEN(block_length));
+
 		/*
 		 * Disable the PDC controller
 		 */
@@ -584,6 +627,11 @@ static void at91_mci_process_next(struct at91mci_host *host)
 		at91_mci_send_command(host, host->request->stop);
 	} else {
 		del_timer(&host->timer);
+		/* the at91rm9200 mci controller hangs after some transfers,
+		 * and the workaround is to reset it after each transfer.
+		 */
+		if (cpu_is_at91rm9200())
+			at91_reset_host(host);
 		mmc_request_done(host->mmc, host->request);
 	}
 }