arm: spear: Add command to switch between 1-bit HW ECC and SW BCH4

This patch adds the "nandecc" command to switch between the SPEAr600 internal
1-bit HW ECC and the 4-bit SW BCH4 ECC. This can be needed to support NAND
chips with a stronger ECC than 1-bit, as on the x600. And to dynamically
switch between both ECC schemes for backwards compatibility.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

arch/arm/cpu/arm926ejs/spear/cpu.c

@@ -83,3 +83,37 @@ int print_cpuinfo(void)
 	return 0;
 }
 #endif
+
+#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_NAND_ECC_BCH)
+static int do_switch_ecc(cmd_tbl_t *cmdtp, int flag, int argc,
+			 char *const argv[])
+{
+	if (argc != 2)
+		goto usage;
+
+	if (strncmp(argv[1], "hw", 2) == 0) {
+		/* 1-bit HW ECC */
+		printf("Switching to 1-bit HW ECC\n");
+		fsmc_nand_switch_ecc(1);
+	} else if (strncmp(argv[1], "bch4", 2) == 0) {
+		/* 4-bit SW ECC BCH4 */
+		printf("Switching to 4-bit SW ECC (BCH4)\n");
+		fsmc_nand_switch_ecc(4);
+	} else {
+		goto usage;
+	}
+
+	return 0;
+
+usage:
+	printf("Usage: nandecc %s\n", cmdtp->usage);
+	return 1;
+}
+
+U_BOOT_CMD(
+	nandecc, 2, 0,	do_switch_ecc,
+	"switch NAND ECC calculation algorithm",
+	"hw|bch4 - Switch between NAND hardware 1-bit HW and"
+	" 4-bit SW BCH\n"
+);
+#endif

arch/arm/include/asm/arch-spear/spr_misc.h

@@ -253,5 +253,6 @@ struct misc_regs {
 #define SOC_SPEAR320		203
 
 extern int get_socrev(void);
+int fsmc_nand_switch_ecc(uint32_t eccstrength);
 
 #endif