openwrt/target/linux/brcm2708/patches-4.1/0130-bcm2835-sdhost-Ignore-CRC7-for-MMC-CMD1.patch

From 0bb775b407dab3bab972663ef47dde38b0d34c24 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Mon, 20 Jul 2015 17:32:18 +0100
Subject: [PATCH 130/171] bcm2835-sdhost: Ignore CRC7 for MMC CMD1

It seems that the sdhost interface returns CRC7 errors for CMD1,
which is the MMC-specific SEND_OP_COND. Returning these errors to
the MMC layer causes a downward spiral, but ignoring them seems
to be harmless.
---
 drivers/mmc/host/bcm2835-sdhost.c | 39 +++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 16 deletions(-)

--- a/drivers/mmc/host/bcm2835-sdhost.c
+++ b/drivers/mmc/host/bcm2835-sdhost.c
@@ -959,25 +959,32 @@ static void bcm2835_sdhost_finish_comman
 				mmc_hostname(host->mmc), sdcmd, sdhsts,
 				bcm2835_sdhost_read(host, SDEDM));
 
-		if (sdhsts & SDHSTS_CMD_TIME_OUT) {
-			switch (host->cmd->opcode) {
-			case 5: case 52: case 53:
-				/* Don't warn about SDIO commands */
-				break;
-			default:
-				pr_err("%s: command timeout\n",
+		if ((sdhsts & SDHSTS_CRC7_ERROR) &&
+		    (host->cmd->opcode == 1)) {
+			if (host->debug)
+				pr_info("%s: ignoring CRC7 error for CMD1\n",
+					mmc_hostname(host->mmc));
+		} else {
+			if (sdhsts & SDHSTS_CMD_TIME_OUT) {
+				switch (host->cmd->opcode) {
+				case 5: case 52: case 53:
+					/* Don't warn about SDIO commands */
+					break;
+				default:
+					pr_err("%s: command timeout\n",
+					       mmc_hostname(host->mmc));
+					break;
+				}
+				host->cmd->error = -ETIMEDOUT;
+			} else {
+				pr_err("%s: unexpected command error\n",
 				       mmc_hostname(host->mmc));
-				break;
+				bcm2835_sdhost_dumpregs(host);
+				host->cmd->error = -EIO;
 			}
-			host->cmd->error = -ETIMEDOUT;
-		} else {
-			pr_err("%s: unexpected command error\n",
-			       mmc_hostname(host->mmc));
-			bcm2835_sdhost_dumpregs(host);
-			host->cmd->error = -EIO;
+			tasklet_schedule(&host->finish_tasklet);
+			return;
 		}
-		tasklet_schedule(&host->finish_tasklet);
-		return;
 	}
 
 	if (host->cmd->flags & MMC_RSP_PRESENT) {