mmc: core: Add cache control for eMMC4.5 device
This patch adds cache feature of eMMC4.5 Spec.
If device supports cache capability, host can utilize some specific
operations.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 3704727..c0cb225 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -851,16 +851,18 @@
static int mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req)
{
struct mmc_blk_data *md = mq->data;
+ struct mmc_card *card = md->queue.card;
+ int ret = 0;
- /*
- * No-op, only service this because we need REQ_FUA for reliable
- * writes.
- */
+ ret = mmc_flush_cache(card);
+ if (ret)
+ ret = -EIO;
+
spin_lock_irq(&md->lock);
- __blk_end_request_all(req, 0);
+ __blk_end_request_all(req, ret);
spin_unlock_irq(&md->lock);
- return 1;
+ return ret ? 0 : 1;
}
/*
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 772de2c..235bb6a 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2158,6 +2158,65 @@
}
EXPORT_SYMBOL(mmc_card_can_sleep);
+/*
+ * Flush the cache to the non-volatile storage.
+ */
+int mmc_flush_cache(struct mmc_card *card)
+{
+ struct mmc_host *host = card->host;
+ int err = 0;
+
+ if (!(host->caps2 & MMC_CAP2_CACHE_CTRL))
+ return err;
+
+ if (mmc_card_mmc(card) &&
+ (card->ext_csd.cache_size > 0) &&
+ (card->ext_csd.cache_ctrl & 1)) {
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_FLUSH_CACHE, 1, 0);
+ if (err)
+ pr_err("%s: cache flush error %d\n",
+ mmc_hostname(card->host), err);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(mmc_flush_cache);
+
+/*
+ * Turn the cache ON/OFF.
+ * Turning the cache OFF shall trigger flushing of the data
+ * to the non-volatile storage.
+ */
+int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
+{
+ struct mmc_card *card = host->card;
+ int err = 0;
+
+ if (!(host->caps2 & MMC_CAP2_CACHE_CTRL) ||
+ mmc_card_is_removable(host))
+ return err;
+
+ if (card && mmc_card_mmc(card) &&
+ (card->ext_csd.cache_size > 0)) {
+ enable = !!enable;
+
+ if (card->ext_csd.cache_ctrl ^ enable)
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_CACHE_CTRL, enable, 0);
+ if (err)
+ pr_err("%s: cache %s error %d\n",
+ mmc_hostname(card->host),
+ enable ? "on" : "off",
+ err);
+ else
+ card->ext_csd.cache_ctrl = enable;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(mmc_cache_ctrl);
+
#ifdef CONFIG_PM
/**
@@ -2172,6 +2231,9 @@
cancel_delayed_work(&host->disable);
cancel_delayed_work(&host->detect);
mmc_flush_scheduled_work();
+ err = mmc_cache_ctrl(host, 0);
+ if (err)
+ goto out;
mmc_bus_get(host);
if (host->bus_ops && !host->bus_dead) {
@@ -2197,6 +2259,7 @@
if (!err && !mmc_card_keep_power(host))
mmc_power_off(host);
+out:
return err;
}
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 7939015..de5900a 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -470,6 +470,12 @@
} else
card->ext_csd.generic_cmd6_time = 0;
+ card->ext_csd.cache_size =
+ ext_csd[EXT_CSD_CACHE_SIZE + 0] << 0 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 1] << 8 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 2] << 16 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 3] << 24;
+
out:
return err;
}
@@ -1020,6 +1026,23 @@
}
}
+ /*
+ * If cache size is higher than 0, this indicates
+ * the existence of cache and it can be turned on.
+ */
+ if ((host->caps2 & MMC_CAP2_CACHE_CTRL) &&
+ card->ext_csd.cache_size > 0) {
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_CACHE_CTRL, 1, 0);
+ if (err && err != -EBADMSG)
+ goto free_card;
+
+ /*
+ * Only if no error, cache is turned on successfully.
+ */
+ card->ext_csd.cache_ctrl = err ? 0 : 1;
+ }
+
if (!oldcard)
host->card = card;
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 5513785..32492b7 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -51,6 +51,7 @@
u8 rel_sectors;
u8 rel_param;
u8 part_config;
+ u8 cache_ctrl;
u8 rst_n_function;
unsigned int part_time; /* Units: ms */
unsigned int sa_timeout; /* Units: 100ns */
@@ -67,6 +68,7 @@
bool enhanced_area_en; /* enable bit */
unsigned long long enhanced_area_offset; /* Units: Byte */
unsigned int enhanced_area_size; /* Units: KB */
+ unsigned int cache_size; /* Units: KB */
u8 raw_partition_support; /* 160 */
u8 raw_erased_mem_count; /* 181 */
u8 raw_ext_csd_structure; /* 194 */
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index e918120..67bac37 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -177,6 +177,8 @@
extern void mmc_do_release_host(struct mmc_host *host);
extern int mmc_try_claim_host(struct mmc_host *host);
+extern int mmc_flush_cache(struct mmc_card *);
+
/**
* mmc_claim_host - exclusively claim a host
* @host: mmc host to claim
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index cd10208..16e9338 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -239,6 +239,7 @@
unsigned int caps2; /* More host capabilities */
#define MMC_CAP2_BOOTPART_NOACC (1 << 0) /* Boot partition no access */
+#define MMC_CAP2_CACHE_CTRL (1 << 1) /* Allow cache control */
#define MMC_CAP2_POWEROFF_NOTIFY (1 << 2) /* Notify poweroff supported */
mmc_pm_flag_t pm_caps; /* supported pm features */
@@ -349,6 +350,8 @@
extern void mmc_detect_change(struct mmc_host *, unsigned long delay);
extern void mmc_request_done(struct mmc_host *, struct mmc_request *);
+extern int mmc_cache_ctrl(struct mmc_host *, u8);
+
static inline void mmc_signal_sdio_irq(struct mmc_host *host)
{
host->ops->enable_sdio_irq(host, 0);
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 8a05a21..160e4c5 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -270,6 +270,8 @@
* EXT_CSD fields
*/
+#define EXT_CSD_FLUSH_CACHE 32 /* W */
+#define EXT_CSD_CACHE_CTRL 33 /* R/W */
#define EXT_CSD_POWER_OFF_NOTIFICATION 34 /* R/W */
#define EXT_CSD_GP_SIZE_MULT 143 /* R/W */
#define EXT_CSD_PARTITION_ATTRIBUTE 156 /* R/W */
@@ -308,6 +310,7 @@
#define EXT_CSD_PWR_CL_DDR_52_360 239 /* RO */
#define EXT_CSD_POWER_OFF_LONG_TIME 247 /* RO */
#define EXT_CSD_GENERIC_CMD6_TIME 248 /* RO */
+#define EXT_CSD_CACHE_SIZE 249 /* RO, 4 bytes */
/*
* EXT_CSD field definitions