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From 5ca694dfd981a371e9b18cdd4a89c002ffaccbc5 Mon Sep 17 00:00:00 2001
From: San Mehat <san@android.com>
Date: Wed, 3 Dec 2008 10:22:59 -0800
Subject: [PATCH 099/134] mmc: mmcblk: Add new feature 'CONFIG_MMC_BLOCK_PARANOID_RESUME'
With this feature enabled, mmcblk will check the card-status before issuing
a transaction *only* after being resumed. This protectes us from issuing
transactions before the sdcard is ready (which can occur if the host driver
deferrs mmc_resume_host() to reduce resume latency)
Signed-off-by: San Mehat <san@android.com>
---
drivers/mmc/card/Kconfig | 7 +++++++
drivers/mmc/card/block.c | 3 +++
drivers/mmc/card/queue.c | 28 ++++++++++++++++++++++++++++
drivers/mmc/card/queue.h | 3 +++
4 files changed, 41 insertions(+), 0 deletions(-)
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -32,6 +32,13 @@ config MMC_BLOCK_BOUNCE
If unsure, say Y here.
+config MMC_BLOCK_PARANOID_RESUME
+ bool "Check card status on resume"
+ depends on MMC_BLOCK
+ default y
+ help
+ Nohelp
+
config SDIO_UART
tristate "SDIO UART/GPS class support"
help
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -643,6 +643,9 @@ static int mmc_blk_resume(struct mmc_car
if (md) {
mmc_blk_set_blksize(md, card);
+#ifdef CONFIG_MMC_BLOCK_PARANOID_RESUME
+ md->queue.check_status = 1;
+#endif
mmc_queue_resume(&md->queue);
}
return 0;
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -14,7 +14,9 @@
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/scatterlist.h>
+#include <linux/delay.h>
+#include <linux/mmc/mmc.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include "queue.h"
@@ -70,7 +72,33 @@ static int mmc_queue_thread(void *d)
continue;
}
set_current_state(TASK_RUNNING);
+#ifdef CONFIG_MMC_BLOCK_PARANOID_RESUME
+ if (mq->check_status) {
+ struct mmc_command cmd;
+ do {
+ int err;
+
+ cmd.opcode = MMC_SEND_STATUS;
+ cmd.arg = mq->card->rca << 16;
+ cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+
+ mmc_claim_host(mq->card->host);
+ err = mmc_wait_for_cmd(mq->card->host, &cmd, 5);
+ mmc_release_host(mq->card->host);
+
+ if (err) {
+ printk(KERN_ERR "%s: failed to get status (%d)\n",
+ __func__, err);
+ msleep(5);
+ continue;
+ }
+ printk(KERN_DEBUG "%s: status 0x%.8x\n", __func__, cmd.resp[0]);
+ } while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
+ (R1_CURRENT_STATE(cmd.resp[0]) == 7));
+ mq->check_status = 0;
+ }
+#endif
mq->issue_fn(mq, req);
} while (1);
up(&mq->thread_sem);
--- a/drivers/mmc/card/queue.h
+++ b/drivers/mmc/card/queue.h
@@ -17,6 +17,9 @@ struct mmc_queue {
char *bounce_buf;
struct scatterlist *bounce_sg;
unsigned int bounce_sg_len;
+#ifdef CONFIG_MMC_BLOCK_PARANOID_RESUME
+ int check_status;
+#endif
};
extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *);
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