| Message ID | 1384959671-5646-1-git-send-email-ludovic.desroches@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 20/11/2013 16:01, ludovic.desroches@atmel.com : > From: Ludovic Desroches <ludovic.desroches@atmel.com> > > 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. > > Cc: <stable@vger.kernel.org> #3.2+ > Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Thanks, bye, > --- > drivers/mmc/host/atmel-mci.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c > index b8dfe0d..289da71 100644 > --- a/drivers/mmc/host/atmel-mci.c > +++ b/drivers/mmc/host/atmel-mci.c > @@ -1193,11 +1193,22 @@ 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; >
Hi, On Thu, Nov 21 2013, Nicolas Ferre wrote: > On 20/11/2013 16:01, ludovic.desroches@atmel.com : >> From: Ludovic Desroches <ludovic.desroches@atmel.com> >> >> 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. >> >> Cc: <stable@vger.kernel.org> #3.2+ >> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> > > Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Thanks, pushed to mmc-next for 3.14. - Chris.
On 26/11/2013 23:24, Chris Ball : > Hi, > > On Thu, Nov 21 2013, Nicolas Ferre wrote: >> On 20/11/2013 16:01, ludovic.desroches@atmel.com : >>> From: Ludovic Desroches <ludovic.desroches@atmel.com> >>> >>> 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. >>> >>> Cc: <stable@vger.kernel.org> #3.2+ >>> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> >> >> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> > > Thanks, pushed to mmc-next for 3.14. Nice, thank you Chris, but what about considering its inclusion in 3.13? I know that it will anyway hit the 3.13.y stable update but I do think that it would be nice to have this fix sooner in official 3.13... Bye,
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c index b8dfe0d..289da71 100644 --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c @@ -1193,11 +1193,22 @@ 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;