mmc: Tinification of the mmc code

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.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 24f4b28..5e84a41 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -26,6 +26,21 @@
 	  option will be removed as soon as all DM_MMC drivers use it, as it
 	  will the only supported behaviour.
 
+config SPL_MMC_TINY
+	bool "Tiny MMC framework in SPL"
+	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 && BLK && DM_MMC_OPS