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>
diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index fce171c..e924211 100644
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -130,6 +130,43 @@
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 @@
host->request->cmd->error = -ETIMEDOUT;
}
+ at91_reset_host(host);
mmc_request_done(host->mmc, host->request);
}
}
@@ -512,6 +550,11 @@
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 @@
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);
}
}