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c6af9cf9 GKH |
1 | From 66b512eda74d59b17eac04c4da1b38d82059e6c9 Mon Sep 17 00:00:00 2001 |
2 | From: Ludovic Desroches <ludovic.desroches@atmel.com> | |
3 | Date: Wed, 20 Nov 2013 16:01:11 +0100 | |
4 | Subject: mmc: atmel-mci: fix timeout errors in SDIO mode when using DMA | |
5 | ||
6 | From: Ludovic Desroches <ludovic.desroches@atmel.com> | |
7 | ||
8 | commit 66b512eda74d59b17eac04c4da1b38d82059e6c9 upstream. | |
9 | ||
10 | With some SDIO devices, timeout errors can happen when reading data. | |
11 | To solve this issue, the DMA transfer has to be activated before sending | |
12 | the command to the device. This order is incorrect in PDC mode. So we | |
13 | have to take care if we are using DMA or PDC to know when to send the | |
14 | MMC command. | |
15 | ||
16 | Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> | |
17 | Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> | |
18 | Signed-off-by: Chris Ball <cjb@laptop.org> | |
19 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
20 | ||
21 | --- | |
22 | drivers/mmc/host/atmel-mci.c | 13 ++++++++++++- | |
23 | 1 file changed, 12 insertions(+), 1 deletion(-) | |
24 | ||
25 | --- a/drivers/mmc/host/atmel-mci.c | |
26 | +++ b/drivers/mmc/host/atmel-mci.c | |
27 | @@ -1188,11 +1188,22 @@ static void atmci_start_request(struct a | |
28 | iflags |= ATMCI_CMDRDY; | |
29 | cmd = mrq->cmd; | |
30 | cmdflags = atmci_prepare_command(slot->mmc, cmd); | |
31 | - atmci_send_command(host, cmd, cmdflags); | |
32 | + | |
33 | + /* | |
34 | + * DMA transfer should be started before sending the command to avoid | |
35 | + * unexpected errors especially for read operations in SDIO mode. | |
36 | + * Unfortunately, in PDC mode, command has to be sent before starting | |
37 | + * the transfer. | |
38 | + */ | |
39 | + if (host->submit_data != &atmci_submit_data_dma) | |
40 | + atmci_send_command(host, cmd, cmdflags); | |
41 | ||
42 | if (data) | |
43 | host->submit_data(host, data); | |
44 | ||
45 | + if (host->submit_data == &atmci_submit_data_dma) | |
46 | + atmci_send_command(host, cmd, cmdflags); | |
47 | + | |
48 | if (mrq->stop) { | |
49 | host->stop_cmdr = atmci_prepare_command(slot->mmc, mrq->stop); | |
50 | host->stop_cmdr |= ATMCI_CMDR_STOP_XFER; |