All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] mmc: atmel-mci: not busy flag has also to be used for read operations
@ 2012-07-24  9:42 ` ludovic.desroches at atmel.com
  0 siblings, 0 replies; 6+ messages in thread
From: ludovic.desroches @ 2012-07-24  9:42 UTC (permalink / raw)
  To: linux-mmc; +Cc: cjb, nicolas.ferre, plagnioj, linux-arm-kernel

From: Ludovic Desroches <ludovic.desroches@atmel.com>

Even if the datasheet says that the not busy flag has to be used only for
write operations, it's false excepted for version lesser than v2xx.
Not waiting the not busy flag for read operations can cause the controller to
hang-up during the initialization of some SD cards.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable@vger.kernel.org


Hello,

This is a fix for 3.5 and later.

Due to the big changes into atmel-mci driver to support all atmel mci versions,
a bug was introduced.
With some SD cards (mainly micro) when using DMA, the controller hangs-up after
the first CMD6 command because the next command is sent too early.

Regards

Ludovic


---
 drivers/mmc/host/atmel-mci.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index f2c115e..b6abfa7 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -81,6 +81,7 @@ struct atmel_mci_caps {
 	bool	has_bad_data_ordering;
 	bool	need_reset_after_xfer;
 	bool	need_blksz_mul_4;
+	bool	need_notbusy_for_read_ops;
 };
 
 struct atmel_mci_dma {
@@ -1619,7 +1620,8 @@ static void atmci_tasklet_func(unsigned long priv)
 				__func__);
 			atmci_set_completed(host, EVENT_XFER_COMPLETE);
 
-			if (host->data->flags & MMC_DATA_WRITE) {
+			if (host->caps.need_notbusy_for_read_ops
+			    || (host->data->flags & MMC_DATA_WRITE)) {
 				atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
 				state = STATE_WAITING_NOTBUSY;
 			} else if (host->mrq->stop) {
@@ -2212,6 +2214,7 @@ static void __init atmci_get_cap(struct atmel_mci *host)
 	host->caps.has_bad_data_ordering = 1;
 	host->caps.need_reset_after_xfer = 1;
 	host->caps.need_blksz_mul_4 = 1;
+	host->caps.need_notbusy_for_read_ops = 0;
 
 	/* keep only major version number */
 	switch (version & 0xf00) {
@@ -2232,6 +2235,7 @@ static void __init atmci_get_cap(struct atmel_mci *host)
 	case 0x200:
 		host->caps.has_rwproof = 1;
 		host->caps.need_blksz_mul_4 = 0;
+		host->caps.need_notbusy_for_read_ops = 1;
 	case 0x100:
 		host->caps.has_bad_data_ordering = 0;
 		host->caps.need_reset_after_xfer = 0;
-- 
1.7.5.4

^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2012-08-09  6:29 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-07-24  9:42 [PATCH] mmc: atmel-mci: not busy flag has also to be used for read operations ludovic.desroches
2012-07-24  9:42 ` ludovic.desroches at atmel.com
2012-08-08  3:05 ` Chris Ball
2012-08-08  3:05   ` Chris Ball
2012-08-09  6:29   ` ludovic.desroches
2012-08-09  6:29     ` ludovic.desroches

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.