block: support embedded device command line partition

[firefly-linux-kernel-4.4.55.git] / block / partitions / cmdline.c

diff --git a/block/partitions/cmdline.c b/block/partitions/cmdline.c
new file mode 100644 (file)
index 0000000..56cf4ff
--- /dev/null
+++ b/block/partitions/cmdline.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2013 HUAWEI
+ * Author: Cai Zhiyong <caizhiyong@huawei.com>
+ *
+ * Read block device partition table from command line.
+ * The partition used for fixed block device (eMMC) embedded device.
+ * It is no MBR, save storage space. Bootloader can be easily accessed
+ * by absolute address of data on the block device.
+ * Users can easily change the partition.
+ *
+ * The format for the command line is just like mtdparts.
+ *
+ * Verbose config please reference "Documentation/block/cmdline-partition.txt"
+ *
+ */
+
+#include <linux/cmdline-parser.h>
+
+#include "check.h"
+#include "cmdline.h"
+
+static char *cmdline;
+static struct cmdline_parts *bdev_parts;
+
+static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
+{
+       int label_min;
+       struct partition_meta_info *info;
+       char tmp[sizeof(info->volname) + 4];
+       struct parsed_partitions *state = (struct parsed_partitions *)param;
+
+       if (slot >= state->limit)
+               return 1;
+
+       put_partition(state, slot, subpart->from >> 9,
+                     subpart->size >> 9);
+
+       info = &state->parts[slot].info;
+
+       label_min = min_t(int, sizeof(info->volname) - 1,
+                         sizeof(subpart->name));
+       strncpy(info->volname, subpart->name, label_min);
+       info->volname[label_min] = '\0';
+
+       snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
+       strlcat(state->pp_buf, tmp, PAGE_SIZE);
+
+       state->parts[slot].has_info = true;
+
+       return 0;
+}
+
+static int __init cmdline_parts_setup(char *s)
+{
+       cmdline = s;
+       return 1;
+}
+__setup("blkdevparts=", cmdline_parts_setup);
+
+/*
+ * Purpose: allocate cmdline partitions.
+ * Returns:
+ * -1 if unable to read the partition table
+ *  0 if this isn't our partition table
+ *  1 if successful
+ */
+int cmdline_partition(struct parsed_partitions *state)
+{
+       sector_t disk_size;
+       char bdev[BDEVNAME_SIZE];
+       struct cmdline_parts *parts;
+
+       if (cmdline) {
+               if (bdev_parts)
+                       cmdline_parts_free(&bdev_parts);
+
+               if (cmdline_parts_parse(&bdev_parts, cmdline)) {
+                       cmdline = NULL;
+                       return -1;
+               }
+               cmdline = NULL;
+       }
+
+       if (!bdev_parts)
+               return 0;
+
+       bdevname(state->bdev, bdev);
+       parts = cmdline_parts_find(bdev_parts, bdev);
+       if (!parts)
+               return 0;
+
+       disk_size = get_capacity(state->bdev->bd_disk) << 9;
+
+       cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
+
+       strlcat(state->pp_buf, "\n", PAGE_SIZE);
+
+       return 1;
+}