@@ -1181,11 +1181,22 @@ 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;
This is a note to let you know that I have just added a patch titled mmc: atmel-mci: fix timeout errors in SDIO mode when using DMA to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.18. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 113755f73ac6591b3d73cf2778d798a658aaeb4b Mon Sep 17 00:00:00 2001 From: Ludovic Desroches <ludovic.desroches@atmel.com> Date: Wed, 20 Nov 2013 16:01:11 +0100 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- drivers/mmc/host/atmel-mci.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) -- 1.8.3.2