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Groups > linux.kernel > #1705674

[RFC PATCH 1/7] mmc: sdhci: Add quirk to indicate no CRC stripping in MMC_RSP_136

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TI's implementation of sdhci controller used in DRA7 SoC's doesn't
strip CRC in responses with length 136 bits. Add quirk to indicate
the controller does not strip CRC in MMC_RSP_136. If this quirk is
set sdhci library shouldn't shift the response present in
SDHCI_RESPONSE register.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/mmc/host/sdhci.c | 27 +++++++++++++++++++--------
 drivers/mmc/host/sdhci.h |  2 ++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ecd0d4350e8a..ece3751d2a25 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1182,14 +1182,25 @@ static void sdhci_finish_command(struct sdhci_host *host)
 
 	if (cmd->flags & MMC_RSP_PRESENT) {
 		if (cmd->flags & MMC_RSP_136) {
-			/* CRC is stripped so we need to do some shifting. */
-			for (i = 0;i < 4;i++) {
-				cmd->resp[i] = sdhci_readl(host,
-					SDHCI_RESPONSE + (3-i)*4) << 8;
-				if (i != 3)
-					cmd->resp[i] |=
-						sdhci_readb(host,
-						SDHCI_RESPONSE + (3-i)*4-1);
+			if (!(host->quirks2 & SDHCI_QUIRK2_NO_CRC_STRIPPING)) {
+				/*
+				 * CRC is stripped so we need to do some
+				 * shifting.
+				 */
+				for (i = 0; i < 4; i++) {
+					cmd->resp[i] =
+						sdhci_readl(host, SDHCI_RESPONSE
+							    + (3 - i) * 4) << 8;
+					if (i != 3)
+						cmd->resp[i] |=
+						sdhci_readb(host, SDHCI_RESPONSE
+							    + (3 - i) * 4 - 1);
+				}
+			} else {
+				for (i = 0; i < 4; i++)
+					cmd->resp[i] =
+					sdhci_readl(host, SDHCI_RESPONSE +
+						    (3 - i) * 4);
 			}
 		} else {
 			cmd->resp[0] = sdhci_readl(host, SDHCI_RESPONSE);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 0469fa191493..6905131f603d 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -435,6 +435,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK2_ACMD23_BROKEN			(1<<14)
 /* Broken Clock divider zero in controller */
 #define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN		(1<<15)
+/* Controller does not have CRC stripped in Command Response */
+#define SDHCI_QUIRK2_NO_CRC_STRIPPING			(1<<16)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
-- 
2.11.0

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[RFC PATCH 1/7] mmc: sdhci: Add quirk to indicate no CRC stripping in MMC_RSP_136 Kishon Vijay Abraham I <kishon@ti.com> - 2017-08-07 18:10 +0200

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