path: root/drivers
diff options
authorLudovic Desroches <ludovic.desroches@atmel.com>2013-11-20 16:01:11 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-13 13:48:00 -0800
commit6bf1831daef67ae1a1b183ebed11885ea9bf9e1d (patch)
tree664dd97e7224a385577278d9c2602208a1870e00 /drivers
parent1e06335d339132ecbb4196ede2cf1c2b618b0121 (diff)
mmc: atmel-mci: fix timeout errors in SDIO mode when using DMA
commit 66b512eda74d59b17eac04c4da1b38d82059e6c9 upstream. With some SDIO devices, timeout errors can happen when reading data. To solve this issue, the DMA transfer has to be activated before sending the command to the device. This order is incorrect in PDC mode. So we have to take care if we are using DMA or PDC to know when to send the MMC command. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Chris Ball <cjb@laptop.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index b5c95043f7e..84b054b0846 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1188,11 +1188,22 @@ static void atmci_start_request(struct atmel_mci *host,
iflags |= ATMCI_CMDRDY;
cmd = mrq->cmd;
cmdflags = atmci_prepare_command(slot->mmc, cmd);
- atmci_send_command(host, cmd, cmdflags);
+ /*
+ * DMA transfer should be started before sending the command to avoid
+ * unexpected errors especially for read operations in SDIO mode.
+ * Unfortunately, in PDC mode, command has to be sent before starting
+ * the transfer.
+ */
+ if (host->submit_data != &atmci_submit_data_dma)
+ atmci_send_command(host, cmd, cmdflags);
if (data)
host->submit_data(host, data);
+ if (host->submit_data == &atmci_submit_data_dma)
+ atmci_send_command(host, cmd, cmdflags);
if (mrq->stop) {
host->stop_cmdr = atmci_prepare_command(slot->mmc, mrq->stop);
host->stop_cmdr |= ATMCI_CMDR_STOP_XFER;