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authorChe-Liang Chiou <clchiou@chromium.org>2012-11-28 15:21:13 +0000
committerAndy Fleming <afleming@freescale.com>2013-05-06 16:12:38 -0500
commite95504497ecac46907204b0ee3460b708a2981ac (patch)
treec59e230a6096b5883c83d3399717a3408f601355 /include
parent5ed6f447af60aabd2669d913f673793c1ce48f47 (diff)
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mmc: Split device init to decouple OCR-polling delay
Most of time that MMC driver spends on initializing a device is polling OCR (operation conditions register). To decouple this polling loop, device init is split into two parts: The first part fires the OCR query command, and the second part polls the result. So the caller is now no longer bound to the OCR-polling delay; he may fire the query, go somewhere and then come back later for the result. To use this, call mmc_set_preinit() on any device which needs this. This can save significant amounts of time on boot (e.g. 200ms) by hiding the MMC init time behind other init. Signed-off-by: Che-Liang Chiou <clchiou@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org> Acked-by: Jaehoon Chung <jh80.chung@samsung.com> Signed-off-by: Andy Fleming <afleming@freescale.com>
Diffstat (limited to 'include')
-rw-r--r--include/mmc.h30
1 files changed, 30 insertions, 0 deletions
diff --git a/include/mmc.h b/include/mmc.h
index 8bbc6b6..566db59 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -68,6 +68,7 @@
#define UNUSABLE_ERR -17 /* Unusable Card */
#define COMM_ERR -18 /* Communications Error */
#define TIMEOUT -19
+#define IN_PROGRESS -20 /* operation is in progress */
#define MMC_CMD_GO_IDLE_STATE 0
#define MMC_CMD_SEND_OP_COND 1
@@ -270,6 +271,10 @@ struct mmc {
int (*getcd)(struct mmc *mmc);
int (*getwp)(struct mmc *mmc);
uint b_max;
+ char op_cond_pending; /* 1 if we are waiting on an op_cond command */
+ char init_in_progress; /* 1 if we have done mmc_start_init() */
+ char preinit; /* start init as early as possible */
+ uint op_cond_response; /* the response byte from the last op_cond */
};
int mmc_register(struct mmc *mmc);
@@ -287,6 +292,31 @@ int mmc_getcd(struct mmc *mmc);
int mmc_getwp(struct mmc *mmc);
void spl_mmc_load(void) __noreturn;
+/**
+ * Start device initialization and return immediately; it does not block on
+ * polling OCR (operation condition register) status. Then you should call
+ * mmc_init, which would block on polling OCR status and complete the device
+ * initializatin.
+ *
+ * @param mmc Pointer to a MMC device struct
+ * @return 0 on success, IN_PROGRESS on waiting for OCR status, <0 on error.
+ */
+int mmc_start_init(struct mmc *mmc);
+
+/**
+ * Set preinit flag of mmc device.
+ *
+ * This will cause the device to be pre-inited during mmc_initialize(),
+ * which may save boot time if the device is not accessed until later.
+ * Some eMMC devices take 200-300ms to init, but unfortunately they
+ * must be sent a series of commands to even get them to start preparing
+ * for operation.
+ *
+ * @param mmc Pointer to a MMC device struct
+ * @param preinit preinit flag value
+ */
+void mmc_set_preinit(struct mmc *mmc, int preinit);
+
#ifdef CONFIG_GENERIC_MMC
#define mmc_host_is_spi(mmc) ((mmc)->host_caps & MMC_MODE_SPI)
struct mmc *mmc_spi_init(uint bus, uint cs, uint speed, uint mode);