board: add SDHCI support for PIC32MZDASK board.

Enable MMC, SDHCI, FAT_FS support for PIC32MZ[DA] StarterKit.
Also add custom scripts, rules to boot Linux from microSD card.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>

arch/mips/dts/pic32mzda.dtsi

@@ -150,4 +150,15 @@
 			#gpio-cells = <2>;
 		};
 	};
+
+	sdhci: sdhci@1f8ec000 {
+		compatible = "microchip,pic32mzda-sdhci";
+		reg = <0x1f8ec000 0x100>;
+		interrupts = <191 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&clock REF4CLK>, <&clock PB5CLK>;
+		clock-names = "base_clk", "sys_clk";
+		clock-freq-min-max = <25000000>,<25000000>;
+		bus-width = <4>;
+		status = "disabled";
+	};
 };

arch/mips/dts/pic32mzda_sk.dts

@@ -23,6 +23,9 @@
 };
 
 &clock {
+	microchip,refo2-frequency = <50000000>;
+	microchip,refo4-frequency = <25000000>;
+	microchip,refo5-frequency = <40000000>;
 	status = "okay";
 	u-boot,dm-pre-reloc;
 };
@@ -36,3 +39,7 @@
 	status = "okay";
 	u-boot,dm-pre-reloc;
 };
+
+&sdhci {
+	status = "okay";
+};

configs/pic32mzdask_defconfig

@@ -9,7 +9,6 @@ CONFIG_DEFAULT_DEVICE_TREE="pic32mzda_sk"
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="dask # "
 # CONFIG_CMD_IMLS is not set
-# CONFIG_CMD_EXPORTENV is not set
 # CONFIG_CMD_SAVEENV is not set
 CONFIG_LOOPW=y
 CONFIG_CMD_MEMTEST=y
@@ -22,6 +21,8 @@ CONFIG_CMD_GPIO=y
 CONFIG_CMD_TIME=y
 CONFIG_OF_EMBED=y
 CONFIG_CLK=y
+CONFIG_DM_MMC=y
+CONFIG_PIC32_SDHCI=y
 CONFIG_PINCTRL=y
 # CONFIG_PINCTRL_FULL is not set
 CONFIG_SYS_VSNPRINTF=y

include/configs/pic32mzdask.h

@@ -46,6 +46,7 @@
 
 #define CONFIG_SYS_LOAD_ADDR		0x88500000 /* default load address */
 #define CONFIG_SYS_ENV_ADDR		0x88300000
+#define CONFIG_SYS_FDT_ADDR		0x89d00000
 
 /* Memory Test */
 #define CONFIG_SYS_MEMTEST_START	0x88000000
@@ -77,6 +78,33 @@
  */
 #define CONFIG_OF_LIBFDT	1
 
+/*-----------------------------------------------------------------------
+ * SDHC Configuration
+ */
+#define CONFIG_SDHCI
+#define CONFIG_MMC
+#define CONFIG_GENERIC_MMC
+#define CONFIG_CMD_MMC
+
+/*-----------------------------------------------------------------------
+ * File System Configuration
+ */
+/* FAT FS */
+#define CONFIG_DOS_PARTITION
+#define CONFIG_PARTITION_UUIDS
+#define CONFIG_SUPPORT_VFAT
+#define CONFIG_FS_FAT
+#define CONFIG_FAT_WRITE
+#define CONFIG_CMD_FS_GENERIC
+#define CONFIG_CMD_PART
+#define CONFIG_CMD_FAT
+
+/* EXT4 FS */
+#define CONFIG_FS_EXT4
+#define CONFIG_CMD_EXT2
+#define CONFIG_CMD_EXT4
+#define CONFIG_CMD_EXT4_WRITE
+
 /* -------------------------------------------------
  * Environment
  */
@@ -87,7 +115,34 @@
  * Board boot configuration
  */
 #define CONFIG_TIMESTAMP	/* Print image info with timestamp */
-#define CONFIG_BOOTDELAY	5 /* autoboot after X seconds     */
+#define CONFIG_BOOTDELAY	5
-#undef	CONFIG_BOOTARGS
+
+#define MEM_LAYOUT_ENV_SETTINGS					\
+	"kernel_addr_r="__stringify(CONFIG_SYS_LOAD_ADDR)"\0"	\
+	"fdt_addr_r="__stringify(CONFIG_SYS_FDT_ADDR)"\0"	\
+	"scriptaddr="__stringify(CONFIG_SYS_ENV_ADDR)"\0"
+
+#define CONFIG_LEGACY_BOOTCMD_ENV					\
+	"legacy_bootcmd= "						\
+		"if load mmc 0 ${scriptaddr} uEnv.txt; then "		\
+			"env import -tr ${scriptaddr} ${filesize}; "	\
+			"if test -n \"${bootcmd_uenv}\" ; then "	\
+				"echo Running bootcmd_uenv ...; "	\
+				"run bootcmd_uenv; "			\
+			"fi; "						\
+		"fi; \0"
+
+#define BOOT_TARGET_DEVICES(func)	\
+	func(MMC, mmc, 0)
+
+#include <config_distro_bootcmd.h>
+
+#define CONFIG_EXTRA_ENV_SETTINGS	\
+	MEM_LAYOUT_ENV_SETTINGS		\
+	CONFIG_LEGACY_BOOTCMD_ENV	\
+	BOOTENV
+
+#undef CONFIG_BOOTCOMMAND
+#define CONFIG_BOOTCOMMAND	"run distro_bootcmd || run legacy_bootcmd"
 
 #endif	/* __PIC32MZDASK_CONFIG_H */