@@ -270,4 +270,12 @@ config CMDLINE_PARTITION
Say Y here if you want to read the partition table from bootargs.
The format for the command line is just like mtdparts.
+config OF_PARTITION
+ bool "Command line partition support" if PARTITION_ADVANCED
+ depends on OF
+ help
+ Say Y here if you want to enable support for partition table
+ defined in Device Tree. (mainly for eMMC)
+ The format for the command line is just like MTD fixed-partition schema.
+
endmenu
@@ -12,6 +12,7 @@ obj-$(CONFIG_CMDLINE_PARTITION) += cmdline.o
obj-$(CONFIG_MAC_PARTITION) += mac.o
obj-$(CONFIG_LDM_PARTITION) += ldm.o
obj-$(CONFIG_MSDOS_PARTITION) += msdos.o
+obj-$(CONFIG_OF_PARTITION) += of.o
obj-$(CONFIG_OSF_PARTITION) += osf.o
obj-$(CONFIG_SGI_PARTITION) += sgi.o
obj-$(CONFIG_SUN_PARTITION) += sun.o
new file mode 100644
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/blkdev.h>
+#include <linux/of.h>
+#include "check.h"
+
+#define BOOT0_STR "boot0"
+#define BOOT1_STR "boot1"
+
+static struct device_node *get_partitions_node(struct device_node *disk_np,
+ const char *disk_name)
+{
+ const char *node_name = "partitions";
+
+ /* Check if we are parsing boot0 or boot1 */
+ if (!memcmp(disk_name + strlen(disk_name) - strlen(BOOT0_STR),
+ BOOT0_STR, sizeof(BOOT0_STR)))
+ node_name = "partitions-boot0";
+ if (!memcmp(disk_name + strlen(disk_name) - strlen(BOOT1_STR),
+ BOOT1_STR, sizeof(BOOT1_STR)))
+ node_name = "partitions-boot1";
+
+ return of_get_child_by_name(disk_np, node_name);
+}
+
+static void add_of_partition(struct parsed_partitions *state, int slot,
+ struct device_node *np)
+{
+ struct partition_meta_info *info;
+ char tmp[sizeof(info->volname) + 4];
+ int a_cells, s_cells;
+ const char *partname;
+ const __be32 *reg;
+ u64 offset, size;
+ int len;
+
+ reg = of_get_property(np, "reg", &len);
+
+ a_cells = of_n_addr_cells(np);
+ s_cells = of_n_size_cells(np);
+
+ offset = of_read_number(reg, a_cells);
+ size = of_read_number(reg + a_cells, s_cells);
+
+ put_partition(state, slot, offset, size);
+
+ if (of_property_read_bool(pp, "read-only"))
+ state->parts[slot].flags |= ADDPART_FLAG_READONLY;
+
+ info = &state->parts[slot].info;
+ partname = of_get_property(np, "label", &len);
+ strscpy(info->volname, partname, sizeof(info->volname));
+
+ snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
+ strlcat(state->pp_buf, tmp, PAGE_SIZE);
+}
+
+int of_partition(struct parsed_partitions *state)
+{
+ struct device_node *disk_np, *partitions_np, *np;
+ struct device *ddev = disk_to_dev(state->disk);
+ int slot = 1;
+
+ disk_np = of_node_get(ddev->parent->of_node);
+ if (!disk_np)
+ return 0;
+
+ partitions_np = get_partitions_node(disk_np,
+ state->disk->disk_name);
+ if (!partitions_np)
+ return 0;
+
+ for_each_child_of_node(partitions_np, np) {
+ if (slot >= state->limit)
+ return -1;
+
+ add_of_partition(state, slot, np);
+
+ slot++;
+ }
+
+ strlcat(state->pp_buf, "\n", PAGE_SIZE);
+
+ return 1;
+}
Add support for partition table defined in Device Tree. Similar to how it's done with MTD, add support for defining a fixed partition table in device tree. A common scenario for this is fixed block (eMMC) embedded devices that have no MBR or GPT partition table to save storage space. Bootloader access the block device with absolute address of data. This is to complete the functionality with an equivalent implementation with providing partition table with bootargs, for case where the booargs can't be modified and tweaking the Device Tree is the only solution to have an usabe partition table. The implementation follow the fixed-partitions parser used on MTD devices where a "partitions" node is expected to be declared in the OF node of the disk device (mmc-card for eMMC for example) and each child node declare a label and a reg with offset and size. Eventually is also possible to declare the read-only property to flag the partition as read-only. The driver scan the disk name and check if it's suffixed with boot0 or boot1. This is to handle the additional disk provided by eMMC or UFS devices in general. If this suffix is detected, "partitions-boot0" or "partitions-boot1" are used instead of the generic "partitions" Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- block/partitions/Kconfig | 8 ++++ block/partitions/Makefile | 1 + block/partitions/of.c | 85 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 94 insertions(+) create mode 100644 block/partitions/of.c