ARM: AM43XX: board: add support for reading onboard EEPROM

Add support for reading onboard EEPROM to enable
board detection.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

arch/arm/include/asm/arch-am33xx/omap.h

@@ -27,5 +27,7 @@
 #define NON_SECURE_SRAM_START	0x402F0400
 #define NON_SECURE_SRAM_END	0x40340000
 #define SRAM_SCRATCH_SPACE_ADDR	0x40337C00
+#define AM4372_BOARD_NAME_START	SRAM_SCRATCH_SPACE_ADDR
+#define AM4372_BOARD_NAME_END	SRAM_SCRATCH_SPACE_ADDR + 0xC
 #endif
 #endif

board/ti/am43xx/board.c

@@ -9,6 +9,8 @@
  */
 
 #include <common.h>
+#include <i2c.h>
+#include <asm/errno.h>
 #include <spl.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/sys_proto.h>
@@ -17,6 +19,50 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+/*
+ * Read header information from EEPROM into global structure.
+ */
+static int read_eeprom(struct am43xx_board_id *header)
+{
+	/* Check if baseboard eeprom is available */
+	if (i2c_probe(CONFIG_SYS_I2C_EEPROM_ADDR)) {
+		printf("Could not probe the EEPROM at 0x%x\n",
+		       CONFIG_SYS_I2C_EEPROM_ADDR);
+		return -ENODEV;
+	}
+
+	/* read the eeprom using i2c */
+	if (i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR, 0, 2, (uchar *)header,
+		     sizeof(struct am43xx_board_id))) {
+		printf("Could not read the EEPROM\n");
+		return -EIO;
+	}
+
+	if (header->magic != 0xEE3355AA) {
+		/*
+		 * read the eeprom using i2c again,
+		 * but use only a 1 byte address
+		 */
+		if (i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR, 0, 1, (uchar *)header,
+			     sizeof(struct am43xx_board_id))) {
+			printf("Could not read the EEPROM at 0x%x\n",
+			       CONFIG_SYS_I2C_EEPROM_ADDR);
+			return -EIO;
+		}
+
+		if (header->magic != 0xEE3355AA) {
+			printf("Incorrect magic number (0x%x) in EEPROM\n",
+			       header->magic);
+			return -EINVAL;
+		}
+	}
+
+	strncpy(am43xx_board_name, (char *)header->name, sizeof(header->name));
+	am43xx_board_name[sizeof(header->name)] = 0;
+
+	return 0;
+}
+
 #ifdef CONFIG_SPL_BUILD
 
 const struct dpll_params dpll_ddr = {

board/ti/am43xx/board.h

@@ -12,6 +12,38 @@
 #ifndef _BOARD_H_
 #define _BOARD_H_
 
+#include <asm/arch/omap.h>
+
+static char *const am43xx_board_name = (char *)AM4372_BOARD_NAME_START;
+
+/*
+ * TI AM437x EVMs define a system EEPROM that defines certain sub-fields.
+ * We use these fields to in turn see what board we are on, and what
+ * that might require us to set or not set.
+ */
+#define HDR_NO_OF_MAC_ADDR	3
+#define HDR_ETH_ALEN		6
+#define HDR_NAME_LEN		8
+
+struct am43xx_board_id {
+	unsigned int  magic;
+	char name[HDR_NAME_LEN];
+	char version[4];
+	char serial[12];
+	char config[32];
+	char mac_addr[HDR_NO_OF_MAC_ADDR][HDR_ETH_ALEN];
+};
+
+static inline int board_is_eposevm(void)
+{
+	return !strncmp(am43xx_board_name, "AM43EPOS", HDR_NAME_LEN);
+}
+
+static inline int board_is_gpevm(void)
+{
+	return !strncmp(am43xx_board_name, "AM43__GP", HDR_NAME_LEN);
+}
+
 void enable_uart0_pin_mux(void);
 void enable_board_pin_mux(void);
 #endif

include/configs/am43xx_evm.h

@@ -25,6 +25,13 @@
 #define CONFIG_SYS_NS16550_REG_SIZE	(-4)
 #define CONFIG_SYS_NS16550_CLK		48000000
 
+/* I2C Configuration */
+#define CONFIG_CMD_EEPROM
+#define CONFIG_ENV_EEPROM_IS_ON_I2C
+#define CONFIG_SYS_I2C_EEPROM_ADDR	0x50	/* Main EEPROM */
+#define CONFIG_SYS_I2C_EEPROM_ADDR_LEN	2
+#define CONFIG_SYS_I2C_MULTI_EEPROMS
+
 /* SPL defines. */
 #define CONFIG_SPL_TEXT_BASE		0x40300350
 #define CONFIG_SPL_MAX_SIZE		(0x40337C00 - CONFIG_SPL_TEXT_BASE)