add redundant environment for env_sf.c

This patch adds redundant environment for environment in SPI flash.
I took env_flash.c as an example and slightly modified it. Apart
from adapting things to SF, I also slightly changed the decision
logic to use area 2 as a default in case the flags are wrong because
not having a default path worried me.

I did not add a section for CONFIG_ENV_IS_IN_SPI_FLASH in environment.h
because I did not understand if this is desired and/or needed.
So to use the feature, one has to set CONFIG_ENV_OFFSET_REDUND _and_
CONFIG_SYS_REDUNDAND_ENVIRONMENT.

I checked it by powering off my board several times during flash
erase or write, because I do not know if there are other stress
test scenarios.

Signed-off-by: Wolfgang Wegner <w.wegner@astro-kom.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>

common/env_sf.c

@@ -43,6 +43,14 @@
 # define CONFIG_ENV_SPI_MODE	SPI_MODE_3
 #endif
 
+#ifdef CONFIG_ENV_OFFSET_REDUND
+static ulong env_offset = CONFIG_ENV_OFFSET;
+static ulong env_new_offset = CONFIG_ENV_OFFSET_REDUND;
+
+#define ACTIVE_FLAG   1
+#define OBSOLETE_FLAG 0
+#endif /* CONFIG_ENV_ADDR_REDUND */
+
 DECLARE_GLOBAL_DATA_PTR;
 
 /* references to names in env_common.c */
@@ -58,6 +66,229 @@ uchar env_get_char_spec(int index)
 	return *((uchar *)(gd->env_addr + index));
 }
 
+#if defined(CONFIG_ENV_OFFSET_REDUND)
+void swap_env(void)
+{
+	ulong tmp_offset = env_offset;
+
+	env_offset = env_new_offset;
+	env_new_offset = tmp_offset;
+}
+
+int saveenv(void)
+{
+	u32 saved_size, saved_offset;
+	char *saved_buffer = NULL;
+	u32 sector = 1;
+	int ret;
+	char flag = OBSOLETE_FLAG, new_flag = ACTIVE_FLAG;
+
+	if (!env_flash) {
+		puts("Environment SPI flash not initialized\n");
+		return 1;
+	}
+
+	/* Is the sector larger than the env (i.e. embedded) */
+	if (CONFIG_ENV_SECT_SIZE > CONFIG_ENV_SIZE) {
+		saved_size = CONFIG_ENV_SECT_SIZE - CONFIG_ENV_SIZE;
+		saved_offset = env_new_offset + CONFIG_ENV_SIZE;
+		saved_buffer = malloc(saved_size);
+		if (!saved_buffer) {
+			ret = 1;
+			goto done;
+		}
+		ret = spi_flash_read(env_flash, saved_offset,
+					saved_size, saved_buffer);
+		if (ret)
+			goto done;
+	}
+
+	if (CONFIG_ENV_SIZE > CONFIG_ENV_SECT_SIZE) {
+		sector = CONFIG_ENV_SIZE / CONFIG_ENV_SECT_SIZE;
+		if (CONFIG_ENV_SIZE % CONFIG_ENV_SECT_SIZE)
+			sector++;
+	}
+
+	puts("Erasing SPI flash...");
+	ret = spi_flash_erase(env_flash, env_new_offset,
+				sector * CONFIG_ENV_SECT_SIZE);
+	if (ret)
+		goto done;
+
+	puts("Writing to SPI flash...");
+	ret = spi_flash_write(env_flash,
+		env_new_offset + offsetof(env_t, data),
+		sizeof(env_ptr->data), env_ptr->data);
+	if (ret)
+		goto done;
+
+	ret = spi_flash_write(env_flash,
+		env_new_offset + offsetof(env_t, crc),
+		sizeof(env_ptr->crc), &env_ptr->crc);
+	if (ret)
+		goto done;
+
+	ret = spi_flash_write(env_flash,
+		env_offset + offsetof(env_t, flags),
+		sizeof(env_ptr->flags), &flag);
+	if (ret)
+		goto done;
+
+	ret = spi_flash_write(env_flash,
+		env_new_offset + offsetof(env_t, flags),
+		sizeof(env_ptr->flags), &new_flag);
+	if (ret)
+		goto done;
+
+	if (CONFIG_ENV_SECT_SIZE > CONFIG_ENV_SIZE) {
+		ret = spi_flash_write(env_flash, saved_offset,
+					saved_size, saved_buffer);
+		if (ret)
+			goto done;
+	}
+
+	swap_env();
+
+	ret = 0;
+	puts("done\n");
+
+ done:
+	if (saved_buffer)
+		free(saved_buffer);
+	return ret;
+}
+
+void env_relocate_spec(void)
+{
+	int ret;
+	int crc1_ok = 0, crc2_ok = 0;
+	env_t *tmp_env1 = NULL;
+	env_t *tmp_env2 = NULL;
+	uchar flag1, flag2;
+	/* current_env is set only in case both areas are valid! */
+	int current_env = 0;
+
+	tmp_env1 = (env_t *)malloc(CONFIG_ENV_SIZE);
+	if (!tmp_env1) {
+		puts("*** Warning: could not init environment,"
+			" using defaults\n\n");
+		goto out;
+	}
+
+	tmp_env2 = (env_t *)malloc(CONFIG_ENV_SIZE);
+	if (!tmp_env2) {
+		puts("*** Warning: could not init environment,"
+			" using defaults\n\n");
+		goto out;
+	}
+
+	env_flash = spi_flash_probe(CONFIG_ENV_SPI_BUS, CONFIG_ENV_SPI_CS,
+			CONFIG_ENV_SPI_MAX_HZ, CONFIG_ENV_SPI_MODE);
+	if (!env_flash)
+		goto err_probe;
+
+	ret = spi_flash_read(env_flash, CONFIG_ENV_OFFSET,
+				CONFIG_ENV_SIZE, tmp_env1);
+	if (ret)
+		goto err_read;
+
+	if (crc32(0, tmp_env1->data, ENV_SIZE) == tmp_env1->crc)
+		crc1_ok = 1;
+	flag1 = tmp_env1->flags;
+
+	ret = spi_flash_read(env_flash, CONFIG_ENV_OFFSET_REDUND,
+				CONFIG_ENV_SIZE, tmp_env2);
+	if (!ret) {
+		if (crc32(0, tmp_env2->data, ENV_SIZE) == tmp_env2->crc)
+			crc2_ok = 1;
+		flag2 = tmp_env2->flags;
+	}
+
+	if (!crc1_ok && !crc2_ok)
+		goto err_crc;
+	else if (crc1_ok && !crc2_ok) {
+		gd->env_valid = 1;
+		memcpy(env_ptr, tmp_env1, CONFIG_ENV_SIZE);
+	} else if (!crc1_ok && crc2_ok) {
+		gd->env_valid = 1;
+		memcpy(env_ptr, tmp_env2, CONFIG_ENV_SIZE);
+		swap_env();
+	} else if (flag1 == ACTIVE_FLAG && flag2 == OBSOLETE_FLAG) {
+		gd->env_valid = 1;
+		memcpy(env_ptr, tmp_env1, CONFIG_ENV_SIZE);
+	} else if (flag1 == OBSOLETE_FLAG && flag2 == ACTIVE_FLAG) {
+		gd->env_valid = 1;
+		memcpy(env_ptr, tmp_env2, CONFIG_ENV_SIZE);
+		swap_env();
+	} else if (flag1 == flag2) {
+		gd->env_valid = 2;
+		memcpy(env_ptr, tmp_env1, CONFIG_ENV_SIZE);
+		current_env = 1;
+	} else if (flag1 == 0xFF) {
+		gd->env_valid = 2;
+		memcpy(env_ptr, tmp_env1, CONFIG_ENV_SIZE);
+		current_env = 1;
+	} else {
+		/*
+		 * this differs from code in env_flash.c, but I think a sane
+		 * default path is desirable.
+		 */
+		gd->env_valid = 2;
+		memcpy(env_ptr, tmp_env2, CONFIG_ENV_SIZE);
+		swap_env();
+		current_env = 2;
+	}
+	if (current_env == 1) {
+		if (flag2 != OBSOLETE_FLAG) {
+			flag2 = OBSOLETE_FLAG;
+			spi_flash_write(env_flash,
+				env_new_offset + offsetof(env_t, flags),
+				sizeof(env_ptr->flags), &flag2);
+		}
+		if (flag1 != ACTIVE_FLAG) {
+			flag1 = ACTIVE_FLAG;
+			spi_flash_write(env_flash,
+				env_offset + offsetof(env_t, flags),
+				sizeof(env_ptr->flags), &flag1);
+		}
+	} else if (current_env == 2) {
+		if (flag1 != OBSOLETE_FLAG) {
+			flag1 = OBSOLETE_FLAG;
+			spi_flash_write(env_flash,
+				env_new_offset + offsetof(env_t, flags),
+				sizeof(env_ptr->flags), &flag1);
+		}
+		if (flag2 != ACTIVE_FLAG) {
+			flag2 = ACTIVE_FLAG;
+			spi_flash_write(env_flash,
+				env_offset + offsetof(env_t, flags),
+				sizeof(env_ptr->flags), &flag2);
+		}
+	}
+	if (gd->env_valid == 2) {
+		puts("*** Warning - some problems detected "
+			"reading environment; recovered successfully\n\n");
+	}
+	if (tmp_env1)
+		free(tmp_env1);
+	if (tmp_env2)
+		free(tmp_env2);
+	return;
+
+err_read:
+	spi_flash_free(env_flash);
+	env_flash = NULL;
+err_probe:
+err_crc:
+	puts("*** Warning - bad CRC, using default environment\n\n");
+out:
+	if (tmp_env1)
+		free(tmp_env1);
+	if (tmp_env2)
+		free(tmp_env2);
+	set_default_env();
+}
+#else
 int saveenv(void)
 {
 	u32 saved_size, saved_offset;
@@ -144,6 +375,7 @@ err_crc:
 
 	set_default_env();
 }
+#endif
 
 int env_init(void)
 {