@@ -270,4 +270,13 @@ 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 "Device Tree 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 device tree node 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
@@ -62,6 +62,7 @@ int karma_partition(struct parsed_partitions *state);
int ldm_partition(struct parsed_partitions *state);
int mac_partition(struct parsed_partitions *state);
int msdos_partition(struct parsed_partitions *state);
+int of_partition(struct parsed_partitions *state);
int osf_partition(struct parsed_partitions *state);
int sgi_partition(struct parsed_partitions *state);
int sun_partition(struct parsed_partitions *state);
@@ -43,6 +43,9 @@ static int (*const check_part[])(struct parsed_partitions *) = {
#ifdef CONFIG_CMDLINE_PARTITION
cmdline_partition,
#endif
+#ifdef CONFIG_OF_PARTITION
+ of_partition, /* cmdline have priority to OF */
+#endif
#ifdef CONFIG_EFI_PARTITION
efi_partition, /* this must come before msdos */
#endif
new file mode 100644
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/blkdev.h>
+#include <linux/major.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include "check.h"
+
+static int validate_of_partition(struct device_node *np, int slot)
+{
+ int a_cells, s_cells;
+ 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);
+
+ /* Make sure reg len match the expected addr and size cells */
+ if (len / sizeof(*reg) != a_cells + s_cells)
+ return -EINVAL;
+
+ /* Validate offset conversion from bytes to sectors */
+ offset = of_read_number(reg, a_cells);
+ if (offset % SECTOR_SIZE)
+ return -EINVAL;
+
+ /* Validate size conversion from bytes to sectors */
+ size = of_read_number(reg + a_cells, s_cells);
+ if (!size || size % SECTOR_SIZE)
+ return -EINVAL;
+
+ return 0;
+}
+
+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);
+
+ /* Convert bytes to sector size */
+ offset = of_read_number(reg, a_cells) / SECTOR_SIZE;
+ size = of_read_number(reg + a_cells, s_cells) / SECTOR_SIZE;
+
+ put_partition(state, slot, offset, size);
+
+ if (of_property_read_bool(np, "read-only"))
+ state->parts[slot].flags |= ADDPART_FLAG_READONLY;
+
+ /*
+ * Follow MTD label logic, search for label property,
+ * fallback to node name if not found.
+ */
+ info = &state->parts[slot].info;
+ partname = of_get_property(np, "label", &len);
+ if (!partname)
+ partname = of_get_property(np, "name", &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 *partitions_np, *np;
+ struct device *ddev = disk_to_dev(state->disk);
+ int slot;
+
+ partitions_np = of_node_get(ddev->of_node);
+ if (!partitions_np ||
+ !of_device_is_compatible(partitions_np, "fixed-partitions"))
+ return 0;
+
+ slot = 1;
+ /* Validate parition offset and size */
+ for_each_child_of_node(partitions_np, np) {
+ if (validate_of_partition(np, slot)) {
+ of_node_put(np);
+ of_node_put(partitions_np);
+
+ return -1;
+ }
+
+ slot++;
+ }
+
+ slot = 1;
+ for_each_child_of_node(partitions_np, np) {
+ if (slot >= state->limit) {
+ of_node_put(np);
+ break;
+ }
+
+ 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 with "fixed-partitions" compatible 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. If label is not declared, the node name is used as fallback. Eventually is also possible to declare the read-only property to flag the partition as read-only. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- block/partitions/Kconfig | 9 +++ block/partitions/Makefile | 1 + block/partitions/check.h | 1 + block/partitions/core.c | 3 + block/partitions/of.c | 116 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 130 insertions(+) create mode 100644 block/partitions/of.c