[U-Boot] [PATCH v5 2/2] env: mmc: add erase-function

[Frank Wunderlich]

this adds erase environment for mmc storage

squashed fixes:
 - add CONFIG_CMD_ERASEENV
 - env: erase redundant offset if defined

Suggested-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
Signed-off-by: Frank Wunderlich <frank-w at public-files.de>
---
 env/mmc.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/env/mmc.c b/env/mmc.c
index c3cf35d01b..da5cf21637 100644
--- a/env/mmc.c
+++ b/env/mmc.c
@@ -242,6 +242,55 @@ fini:
 	fini_mmc_for_env(mmc);
 	return ret;
 }
+
+#if defined(CONFIG_CMD_ERASEENV)
+static inline int erase_env(struct mmc *mmc, unsigned long size,
+			    unsigned long offset)
+{
+	uint blk_start, blk_cnt, n;
+	struct blk_desc *desc = mmc_get_blk_desc(mmc);
+
+	blk_start	= ALIGN(offset, mmc->write_bl_len) / mmc->write_bl_len;
+	blk_cnt		= ALIGN(size, mmc->write_bl_len) / mmc->write_bl_len;
+
+	n = blk_derase(desc, blk_start, blk_cnt);
+	printf("%d blocks erased: %s\n", n, (n == blk_cnt) ? "OK" : "ERROR");
+
+	return (n == blk_cnt) ? CMD_RET_SUCCESS : CMD_RET_FAILURE;
+}
+
+static int env_mmc_erase(void)
+{
+	int dev = mmc_get_env_dev();
+	struct mmc *mmc = find_mmc_device(dev);
+	int	ret, copy = 0;
+	u32	offset;
+
+	if (!mmc)
+		return CMD_RET_FAILURE;
+
+	if (mmc_getwp(mmc) == 1) {
+		printf("Error: card is write protected!\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (mmc_get_env_addr(mmc, copy, &offset))
+		return CMD_RET_FAILURE;
+
+	ret = erase_env(mmc, CONFIG_ENV_SIZE, offset);
+
+#ifdef CONFIG_ENV_OFFSET_REDUND
+	copy = 1;
+
+	if (mmc_get_env_addr(mmc, copy, &offset))
+		return CMD_RET_FAILURE;
+
+	ret |= erase_env(mmc, CONFIG_ENV_SIZE, offset);
+#endif
+
+	return ret;
+}
+#endif /* CONFIG_CMD_ERASEENV */
 #endif /* CONFIG_CMD_SAVEENV && !CONFIG_SPL_BUILD */

 static inline int read_env(struct mmc *mmc, unsigned long size,
@@ -351,5 +400,8 @@ U_BOOT_ENV_LOCATION(mmc) = {
 	.load		= env_mmc_load,
 #ifndef CONFIG_SPL_BUILD
 	.save		= env_save_ptr(env_mmc_save),
+#if defined(CONFIG_CMD_ERASEENV)
+	.erase		= env_mmc_erase,
+#endif
 #endif
 };
--
2.17.1