[IMX6DL]fastboot erase SD分区实现

u-boot: v2009.08

系统默认只支持nand的fastboot erase功能，而我们用的是SD，当使用fastboot erase时，会提示：

“Not support erase command for EMMC”

SD和EMMC都是基于MMC，u-boot本身有实现mmc的block erase功能，

因此我们利用它来擦写对应的块即可。

在擦写之前，我们需要对应的分区信息，fastboot init那会需要将partition

的信息添加到partition table中，这里是添加userdata分区的例子：

diff --git a/drivers/fastboot/fastboot.c b/drivers/fastboot/fastboot.c
index cb1d176..e7606e0 100644
--- a/drivers/fastboot/fastboot.c
+++ b/drivers/fastboot/fastboot.c
@@ -84,6 +84,8 @@ enum {
     PTN_KERNEL_INDEX,
     PTN_URAMDISK_INDEX,
     PTN_SYSTEM_INDEX,
+    /*Kris, 20160701, add userdata partition. */
+    PTN_USERDATA_INDEX,
     PTN_RECOVERY_INDEX
 };

@@ -406,6 +408,12 @@ static int fastboot_init_mmc_sata_ptable(void)
                                   user_partition,
                                   "system", dev_desc, ptable);

+       /*Kris, 20160701, add userdata partition. */
+       setup_ptable_mmc_partition(PTN_USERDATA_INDEX,
+                                  CONFIG_ANDROID_USERDATA_PARTITION_MMC,
+                                  user_partition,
+                                  "userdata", dev_desc, ptable);
+
        for (i = 0; i <= PTN_RECOVERY_INDEX; i++)
                fastboot_flash_add_ptn(&ptable[i]);

diff --git a/include/configs/mx6_tek_android.h b/include/configs/mx6_tek_android.h
index e9ea67f..20a515c 100644
--- a/include/configs/mx6_tek_android.h
+++ b/include/configs/mx6_tek_android.h
@@ -59,6 +59,9 @@
 #define CONFIG_ANDROID_RECOVERY_PARTITION_MMC 2
 #define CONFIG_ANDROID_CACHE_PARTITION_MMC 6

+/*Kris, 20160701, add userdata partition. */
+#define CONFIG_ANDROID_USERDATA_PARTITION_MMC  4
+

这里的CONFIG_ANDROID_USERDATA_PARTITION_MMC的值一定要和你的具体分区信息对应，

比如我的userdata分区是/dev/block/mmcblk0p4, 因此是分区4.

接着就可以实现fastboot erase功能了，对应的fastboot命令接收函数是rx_handler(),

改动如下：

diff --git a/common/cmd_fastboot.c b/common/cmd_fastboot.c
index 900ed1a..eff8d8a 100644
--- a/common/cmd_fastboot.c
+++ b/common/cmd_fastboot.c
@@ -939,8 +939,55 @@ static int rx_handler (const unsigned char *buffer, unsigned int buffer_size)
                        }
                        ret = 0;
 #else
+/*Kris,20160701, support erase partition. {*/
+#if 0
                        printf("Not support erase command for EMMC\n");
                        ret = -1;
+#else
+                       struct fastboot_ptentry *ptn;
+                       char slot_no[32], offset[32],  length[32], part_no[32];
+                       unsigned int temp;
+
+                       /* Next is the partition name */
+                       ptn = fastboot_flash_find_ptn(cmdbuf + 6);
+                       if (ptn == 0) {
+                               printf("Partition:'%s' does not exist\n",cmdbuf + 6);
+                               sprintf(response, "FAILpartition does not exist");
+                       }
+
+                       printf("erase partition '%s'\n", ptn->name);
+                       char *mmc_erase[4] = {"mmc", "erase", NULL, NULL};
+                       char *mmc_dev[4] = {"mmc", "dev", NULL, NULL};
+
+                       mmc_dev[2] = slot_no;
+                       mmc_dev[3] = part_no;
+                       mmc_erase[2] = offset;
+                       mmc_erase[3] = length;
+
+                       sprintf(offset, "0x%x", ptn->start);
+                       temp = (ptn->length +MMC_SATA_BLOCK_SIZE - 1) / MMC_SATA_BLOCK_SIZE;
+                       sprintf(length, "0x%x", temp);
+                       sprintf(slot_no, "%d", fastboot_devinfo.dev_id);
+                       sprintf(part_no, "%d", ptn->partition_id);
+
+                       printf("Initializing '%s'\n", ptn->name);
+                       if (do_mmcops(NULL, 0, 4, mmc_dev))
+                               sprintf(response, "FAIL:Init of MMC card");
+                       else
+                               sprintf(response, "OKAY");
+
+                       printf("Erasing '%s'\n", ptn->name);
+                       if (do_mmcops(NULL, 0, 4, mmc_erase)) {
+                               printf("Erasing '%s' FAILED!\n", ptn->name);
+                               sprintf(response, "FAIL: Write partition");
+                       } else {
+                               printf("Erasing '%s' DONE!\n", ptn->name);
+                               sprintf(response, "OKAY");
+                       }
+                       ret = 0;
+#endif
+/*Kris,20160701, support erase partition. }*/
+
 #endif

这样就可以erase了(其他分区也通用)，userdata比较大，所以erase有一会儿：

[[email protected]:~]$ sudo fastboot erase userdata

erasing ‘userdata‘...

OKAY [126.140s]

finished. total time: 126.140s

当然erase之后还需要将useradata image download进去，否则会因无文件系统而挂载失败。

编译了个5M大小的image,主要用它的文件系统。

[[email protected]:~]$ sudo fastboot flash userdata userdata.img

sending ‘userdata‘ (5120 KB)...

OKAY [  4.915s]

writing ‘userdata‘...

OKAY [  0.586s]

finished. total time: 5.501s