[U-Boot] [PATCH V2] mmc: Tinification of the mmc code

[Marek Vasut]

Add new configuration option CONFIG_MMC_TINY which strips away all
memory allocation within the MMC code and code for handling multiple
cards. This allows extremely space-constrained SPL code use the MMC
framework.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Tom Rini <trini at konsulko.com>
Cc: Simon Glass <sjg at chromium.org>
---
V2: Switch the MMC_TINY option to Kconfig
---
 common/spl/spl_mmc.c |  6 +++++-
 drivers/mmc/Kconfig  | 16 ++++++++++++++
 drivers/mmc/Makefile |  6 ++++++
 drivers/mmc/mmc.c    | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 include/mmc.h        |  1 +
 5 files changed, 87 insertions(+), 3 deletions(-)

diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
index dcfd842..6508b3e 100644
--- a/common/spl/spl_mmc.c
+++ b/common/spl/spl_mmc.c
@@ -300,7 +300,11 @@ int spl_mmc_load_image(u32 boot_device)
 			if (part == 7)
 				part = 0;
 
-			err = blk_dselect_hwpart(mmc_get_blk_desc(mmc), part);
+			if (CONFIG_IS_ENABLED(MMC_TINY))
+				err = mmc_switch_part(mmc, part);
+			else
+				err = blk_dselect_hwpart(mmc_get_blk_desc(mmc), part);
+
 			if (err) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
 				puts("spl: mmc partition switch failed\n");
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index c80efc3..365057b 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -16,6 +16,22 @@ config DM_MMC
 	  appear as block devices in U-Boot and can support filesystems such
 	  as EXT4 and FAT.
 
+config SPL_MMC_TINY
+	bool "Tiny MMC framework in SPL"
+	default n
+	help
+	  Enable MMC framework tinification support. This option is useful if
+	  if your SPL is extremely size constrained. Heed the warning, enable
+	  this option if and only if you know exactly what you are doing, if
+	  you are reading this help text, you most likely have no idea :-)
+
+	  The MMC framework is reduced to bare minimum to be useful. No malloc
+	  support is needed for the MMC framework operation with this option
+	  enabled. The framework supports exactly one MMC device and exactly
+	  one MMC driver. The MMC driver can be adjusted to avoid any malloc
+	  operations too, which can remove the need for malloc support in SPL
+	  and thus further reduce footprint.
+
 config MSM_SDHCI
 	bool "Qualcomm SDHCI controller"
 	depends on DM_MMC
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index 3da4817..89578d2 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -10,8 +10,14 @@ obj-$(CONFIG_GENERIC_MMC) += mmc-uclass.o
 endif
 
 ifndef CONFIG_BLK
+ifdef CONFIG_SPL_BUILD
+ifndef CONFIG_SPL_MMC_TINY
 obj-$(CONFIG_GENERIC_MMC) += mmc_legacy.o
 endif
+else
+obj-$(CONFIG_GENERIC_MMC) += mmc_legacy.o
+endif
+endif
 
 obj-$(CONFIG_ARM_PL180_MMCI) += arm_pl180_mmci.o
 obj-$(CONFIG_ATMEL_SDHCI) += atmel_sdhci.o
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index a4a2161..4875f45 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -21,6 +21,29 @@
 #include <div64.h>
 #include "mmc_private.h"
 
+#if CONFIG_IS_ENABLED(MMC_TINY)
+static struct mmc mmc_static;
+struct mmc *find_mmc_device(int dev_num)
+{
+	return &mmc_static;
+}
+
+void mmc_do_preinit(void)
+{
+	struct mmc *m = &mmc_static;
+#ifdef CONFIG_FSL_ESDHC_ADAPTER_IDENT
+	mmc_set_preinit(m, 1);
+#endif
+	if (m->preinit)
+		mmc_start_init(m);
+}
+
+struct blk_desc *mmc_get_blk_desc(struct mmc *mmc)
+{
+	return &mmc->block_dev;
+}
+#endif
+
 __weak int board_mmc_getwp(struct mmc *mmc)
 {
 	return -1;
@@ -238,7 +261,11 @@ static ulong mmc_bread(struct blk_desc *block_dev, lbaint_t start,
 	if (!mmc)
 		return 0;
 
-	err = blk_dselect_hwpart(block_dev, block_dev->hwpart);
+	if (CONFIG_IS_ENABLED(MMC_TINY))
+		err = mmc_switch_part(mmc, block_dev->hwpart);
+	else
+		err = blk_dselect_hwpart(block_dev, block_dev->hwpart);
+
 	if (err < 0)
 		return 0;
 
@@ -568,7 +595,7 @@ static int mmc_set_capacity(struct mmc *mmc, int part_num)
 	return 0;
 }
 
-static int mmc_switch_part(struct mmc *mmc, unsigned int part_num)
+int mmc_switch_part(struct mmc *mmc, unsigned int part_num)
 {
 	int ret;
 
@@ -1576,6 +1603,34 @@ int mmc_unbind(struct udevice *dev)
 	return 0;
 }
 
+#elif CONFIG_IS_ENABLED(MMC_TINY)
+static struct mmc mmc_static = {
+	.dsr_imp		= 0,
+	.dsr			= 0xffffffff,
+	.block_dev = {
+		.if_type	= IF_TYPE_MMC,
+		.removable	= 1,
+		.devnum		= 0,
+		.block_read	= mmc_bread,
+		.block_write	= mmc_bwrite,
+		.block_erase	= mmc_berase,
+		.part_type	= 0,
+	},
+};
+
+struct mmc *mmc_create(const struct mmc_config *cfg, void *priv)
+{
+	struct mmc *mmc = &mmc_static;
+
+	mmc->cfg = cfg;
+	mmc->priv = priv;
+
+	return mmc;
+}
+
+void mmc_destroy(struct mmc *mmc)
+{
+}
 #else
 struct mmc *mmc_create(const struct mmc_config *cfg, void *priv)
 {
@@ -1825,8 +1880,10 @@ int mmc_initialize(bd_t *bis)
 	initialized = 1;
 
 #ifndef CONFIG_BLK
+#if !CONFIG_IS_ENABLED(MMC_TINY)
 	mmc_list_init();
 #endif
+#endif
 	ret = mmc_probe(bis);
 	if (ret)
 		return ret;
diff --git a/include/mmc.h b/include/mmc.h
index 7fdfc32..3f6f9d2 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -443,6 +443,7 @@ struct mmc *find_mmc_device(int dev_num);
 int mmc_set_dev(int dev_num);
 void print_mmc_devices(char separator);
 int get_mmc_num(void);
+int mmc_switch_part(struct mmc *mmc, unsigned int part_num);
 int mmc_hwpart_config(struct mmc *mmc, const struct mmc_hwpart_conf *conf,
 		      enum mmc_hwpart_conf_mode mode);
 int mmc_getcd(struct mmc *mmc);
-- 
2.7.0