mmc: atmel-mci: not busy flag has also to be used for read operations

Even if the datasheet says that the not busy flag has to be used only
for write operations, it's false except for version lesser than v2xx.

Not waiting on the not busy flag for read operations can cause the
controller to hang-up during the initialization of some SD cards
with DMA after the first CMD6 -- the next command is sent too early.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: stable <stable@vger.kernel.org> [3.5, 3.6]
Signed-off-by: Chris Ball <cjb@laptop.org>

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 {
@@ -1625,7 +1626,8 @@ 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) {
@@ -2218,6 +2220,7 @@ 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) {
@@ -2238,6 +2241,7 @@ 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;