[U-Boot] [PATCH] mmc: add wrappers for MMC block_{read, write, erase}

[Steve Rae <srae@broadcom.com>]

Each wrapper function:
- switches to the specified physical partition, then
- performs the original function, and then
- switches back to the original physical partition
where the physical partition (aka HW partition) is
  0=User, 1=Boot1, 2=Boot2, etc.

Signed-off-by: Steve Rae <srae@broadcom.com>
---
based on a discussion: http://lists.denx.de/pipermail/u-boot/2014-April/178171.html
The original calling code is (for example):
  mmc->block_dev.block_read(dev_num, start, blkcnt, buffer)
Therefore, these wrappers use the following naming convention:
  mmc_block_read_hwpart(dev_num, part_num, start, blkcnt, buffer)
"hwpart" comes from: Stephen Warren <swarren@nvidia.com>

 drivers/mmc/Makefile     |  1 +
 drivers/mmc/mmc_hwpart.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/mmc.h            | 10 +++++++
 3 files changed, 86 insertions(+)
 create mode 100644 drivers/mmc/mmc_hwpart.c

diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index 4c6ab9e..04f87f9 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_FSL_ESDHC) += fsl_esdhc.o
 obj-$(CONFIG_FTSDC010) += ftsdc010_mci.o
 obj-$(CONFIG_FTSDC021) += ftsdc021_sdhci.o
 obj-$(CONFIG_GENERIC_MMC) += mmc.o
+obj-$(CONFIG_GENERIC_MMC) += mmc_hwpart.o
 obj-$(CONFIG_GENERIC_ATMEL_MCI) += gen_atmel_mci.o
 obj-$(CONFIG_MMC_SPI) += mmc_spi.o
 obj-$(CONFIG_ARM_PL180_MMCI) += arm_pl180_mmci.o
diff --git a/drivers/mmc/mmc_hwpart.c b/drivers/mmc/mmc_hwpart.c
new file mode 100644
index 0000000..1c29f8f
--- /dev/null
+++ b/drivers/mmc/mmc_hwpart.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 Broadcom Corporation.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <mmc.h>
+
+static int switch_part(struct mmc *mmc,
+		       int dev,
+		       unsigned int chk_part_num,
+		       unsigned int part_num)
+{
+	if (!mmc)
+		return -1;
+
+	if (mmc->part_num != chk_part_num) {
+		if (mmc_switch_part(dev, part_num)) {
+			printf("MMC partition switch to %d failed [dev=%d]\n",
+			       part_num, dev);
+			return -1;
+		}
+	}
+	return 0;
+}
+
+unsigned long mmc_block_read_hwpart(int dev,
+				    unsigned int part_num,
+				    lbaint_t start,
+				    lbaint_t blkcnt,
+				    void *buffer)
+{
+	unsigned long rc = 0;
+	struct mmc *mmc = find_mmc_device(dev);
+
+	if (switch_part(mmc, dev, part_num, part_num))
+		return 0;
+	rc = mmc->block_dev.block_read(dev, start, blkcnt, buffer);
+	switch_part(mmc, dev, part_num, mmc->part_num);
+
+	return rc;
+}
+
+unsigned long mmc_block_write_hwpart(int dev,
+				     unsigned int part_num,
+				     lbaint_t start,
+				     lbaint_t blkcnt,
+				     const void *buffer)
+{
+	unsigned long rc = 0;
+	struct mmc *mmc = find_mmc_device(dev);
+
+	if (switch_part(mmc, dev, part_num, part_num))
+		return 0;
+	rc = mmc->block_dev.block_write(dev, start, blkcnt, buffer);
+	switch_part(mmc, dev, part_num, mmc->part_num);
+
+	return rc;
+}
+
+unsigned long mmc_block_erase_hwpart(int dev,
+				     unsigned int part_num,
+				     lbaint_t start,
+				     lbaint_t blkcnt)
+{
+	unsigned long rc = -1;
+	struct mmc *mmc = find_mmc_device(dev);
+
+	if (switch_part(mmc, dev, part_num, part_num))
+		return -1;
+	rc = mmc->block_dev.block_erase(dev, start, blkcnt);
+	switch_part(mmc, dev, part_num, mmc->part_num);
+
+	return rc;
+}
diff --git a/include/mmc.h b/include/mmc.h
index a3a100b..4871c08 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -347,6 +347,16 @@ int mmc_rpmb_read(struct mmc *mmc, void *addr, unsigned short blk,
 		  unsigned short cnt, unsigned char *key);
 int mmc_rpmb_write(struct mmc *mmc, void *addr, unsigned short blk,
 		   unsigned short cnt, unsigned char *key);
+/* Functions to read/write/erase from the specified HW partition */
+unsigned long mmc_block_read_hwpart(int dev, unsigned int part_num,
+				    lbaint_t start, lbaint_t blkcnt,
+				    void *buffer);
+unsigned long mmc_block_write_hwpart(int dev, unsigned int part_num,
+				     lbaint_t start, lbaint_t blkcnt,
+				     const void *buffer);
+
+unsigned long mmc_block_erase_hwpart(int dev, unsigned int part_num,
+				     lbaint_t start, lbaint_t blkcnt);
 /**
  * Start device initialization and return immediately; it does not block on
  * polling OCR (operation condition register) status.  Then you should call
-- 
1.8.5