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.. SPDX-License-Identifier: GPL-2.0+:
mmc command
============
Synopsis
--------
::
mmc info
mmc read addr blk# cnt
mmc write addr blk# cnt
mmc erase blk# cnt
mmc rescan [mode]
mmc part
mmc dev [dev] [part] [mode]
mmc list
mmc wp
mmc bootbus <dev> <boot_bus_width> <reset_boot_bus_width> <boot_mode>
mmc bootpart-resize <dev> <dev part size MB> <RPMB part size MB>
mmc partconf <dev> [[varname] | [<boot_ack> <boot_partition> <partition_access>]]
mmc rst-function <dev> <value>
Description
-----------
The mmc command is used to control MMC(eMMC/SD) device.
The 'mmc info' command displays information (Manufacturer ID, OEM, Name, Bus Speed, Mode, ...) of MMC device.
The 'mmc read' command reads raw data to memory address from MMC device with block offset and count.
The 'mmc write' command writes raw data to MMC device from memory address with block offset and count.
addr
memory address
blk#
start block offset
cnt
block count
The 'mmc erase' command erases *cnt* blocks on the MMC device starting at block *blk#*.
blk#
start block offset
cnt
block count
The 'mmc rescan' command scans the available MMC device.
mode
speed mode to set.
CONFIG_MMC_SPEED_MODE_SET should be enabled. The requested speed mode is
passed as a decimal number according to the following table:
========== ==========================
Speed mode Description
========== ==========================
0 MMC legacy
1 MMC High Speed (26MHz)
2 SD High Speed (50MHz)
3 MMC High Speed (52MHz)
4 MMC DDR52 (52MHz)
5 UHS SDR12 (25MHz)
6 UHS SDR25 (50MHz)
7 UHS SDR50 (100MHz)
8 UHS DDR50 (50MHz)
9 UHS SDR104 (208MHz)
10 HS200 (200MHz)
11 HS400 (200MHz)
12 HS400ES (200MHz)
========== ==========================
A speed mode can be set only if it has already been enabled in the device tree
The 'mmc part' command displays the list available partition on current mmc device.
The 'mmc dev' command shows or set current mmc device.
dev
device number to change
part
partition number to change
mode
speed mode to set.
CONFIG_MMC_SPEED_MODE_SET should be enabled. The requested speed mode is
passed as a decimal number according to the following table:
========== ==========================
Speed mode Description
========== ==========================
0 MMC legacy
1 MMC High Speed (26MHz)
2 SD High Speed (50MHz)
3 MMC High Speed (52MHz)
4 MMC DDR52 (52MHz)
5 UHS SDR12 (25MHz)
6 UHS SDR25 (50MHz)
7 UHS SDR50 (100MHz)
8 UHS DDR50 (50MHz)
9 UHS SDR104 (208MHz)
10 HS200 (200MHz)
11 HS400 (200MHz)
12 HS400ES (200MHz)
========== ==========================
A speed mode can be set only if it has already been enabled in the device tree
The 'mmc list' command displays the list available devices.
The 'mmc wp' command enables "power on write protect" function for boot partitions.
The 'mmc bootbus' command sets the BOOT_BUS_WIDTH field. (*Refer to eMMC specification*)
boot_bus_width
0x0
x1 (sdr) or x4(ddr) buswidth in boot operation mode (default)
0x1
x4 (sdr/ddr) buswidth in boot operation mode
0x2
x8 (sdr/ddr) buswidth in boot operation mode
0x3
Reserved
reset_boot_bus_width
0x0
Reset buswidth to x1, Single data reate and backward compatible timing after boot operation (default)
0x1
Retain BOOT_BUS_WIDTH and BOOT_MODE value after boot operation. This is relevant to Push-pull mode operation only
boot_mode
0x0
Use single data rate + backward compatible timing in boot operation (default)
0x1
Use single data rate + High Speed timing in boot operation mode
0x2
Use dual data rate in boot operation
0x3
Reserved
The 'mmc partconf' command shows or changes PARTITION_CONFIG field.
varname
When showing the PARTITION_CONFIG, an optional environment variable to store the current boot_partition value into.
boot_ack
boot acknowledge value
boot_partition
boot partition to enable for boot
0x0
Device not boot enabled(default)
0x1
Boot partition1 enabled for boot
0x2
Boot partition2 enabled for boot
0x7
User area enabled for boot
others
Reserved
partition_access
partitions to access
The 'mmc bootpart-resize' command changes sizes of boot and RPMB partitions.
dev
device number
boot part size MB
target size of boot partition
RPMB part size MB
target size of RPMB partition
The 'mmc rst-function' command changes the RST_n_FUNCTION field.
**WARNING** : This is a write-once field. (*Refer to eMMC specification*)
value
0x0
RST_n signal is temporarily disabled (default)
0x1
RST_n signal is permanently enabled
0x2
RST_n signal is permanently disabled
0x3
Reserved
Examples
--------
The 'mmc info' command displays device's capabilities:
::
=> mmc info
Device: EXYNOS DWMMC
Manufacturer ID: 45
OEM: 100
Name: SDW16
Bus Speed: 52000000
Mode: MMC DDR52 (52MHz)
Rd Block Len: 512
MMC version 5.0
High Capacity: Yes
Capacity: 14.7 GiB
Bus Width: 8-bit DDR
Erase Group Size: 512 KiB
HC WP Group Size: 8 MiB
User Capacity: 14.7 GiB WRREL
Boot Capacity: 4 MiB ENH
RPMB Capacity: 4 MiB ENH
Boot area 0 is not write protected
Boot area 1 is not write protected
The raw data can be read/written via 'mmc read/write' command:
::
=> mmc read 40000000 5000 100
MMC read: dev # 0, block # 20480, count 256 ... 256 blocks read: OK
=> mmc write 40000000 5000 100
MMC write: dev # 0, block # 20480, count 256 ... 256 blocks written: OK
The partition list can be shown via 'mmc part' command:
::
=> mmc part
Partition Map for MMC device 0 -- Partition Type: DOS
Part Start Sector Num Sectors UUID Type
1 8192 131072 dff8751a-01 0e Boot
2 139264 6291456 dff8751a-02 83
3 6430720 1048576 dff8751a-03 83
4 7479296 23298048 dff8751a-04 05 Extd
5 7481344 307200 dff8751a-05 83
6 7790592 65536 dff8751a-06 83
7 7858176 16384 dff8751a-07 83
8 7876608 22900736 dff8751a-08 83
The current device can be shown or set via 'mmc dev' command:
::
=> mmc dev
switch to partitions #0, OK
mmc0(part0) is current device
=> mmc dev 2 0
switch to partitions #0, OK
mmc2 is current device
=> mmc dev 0 1 4
switch to partitions #1, OK
mmc0(part 1) is current device
The list of available devices can be shown via 'mmc list' command:
::
=> mmc list
mmc list
EXYNOS DWMMC: 0 (eMMC)
EXYNOS DWMMC: 2 (SD)
Configuration
-------------
The mmc command is only available if CONFIG_CMD_MMC=y.
Some commands need to enable more configuration.
write, erase
CONFIG_MMC_WRITE
bootbus, bootpart-resize, partconf, rst-function
CONFIG_SUPPORT_EMMC_BOOT=y
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