Changes between Version 29 and Version 30 of MMC


Ignore:
Timestamp:
06/08/2023 09:02:37 PM (10 months ago)
Author:
Tim Harvey
Comment:

moved U-Boot and Linux partition config under the partition config register details

Legend:

Unmodified
Added
Removed
Modified
  • MMC

    v29 v30  
    4343
    4444[=#emmc-partitions]
    45 === eMMC Partitions ===
     45=== eMMC Partitions
    4646eMMC devices are partitioned into several hardware partitions but only one can be selected at a time:
    4747 - BOOT - one or more small partitions intended for boot firmware (eMMC 4.3 spec requires 2 boot and 1 user partition)
     
    114114
    115115Note that changing your eMMC partitioning differs a bit for each eMMC part (Manufacturer make and model) and needs to be done very early on as it can't succeed after a certain number of writes have occurred. If you need a specific partition configuration for a high volume product contact sales@gateworks.com for more info.
     116
     117[=#emmc-uboot]
     118==== U-Boot Support
     119U-Boot provides access to eMMC devices through the {{{mmc}}} command and interface but adds an additional argument to the {{{mmc}}} interface to describe the hardware partition. The interface is therefore described as 'mmc <dev> <part>' where 'dev' is the mmc device (some boards have more than one) and 'part' is the hardware partition: 0=user, 1=boot0, 2=boot1.
     120
     121Use the {{{mmc dev}}} command to specify the device and partition:
     122{{{#!bash
     123mmc dev 0 0 # select user hw partition
     124mmc dev 0 1 # select boot0 hw partition
     125mmc dev 0 2 # select boot1 hw partition
     126}}}
     127
     128If U-Boot has been built with {{{CONFIG_SUPPORT_EMMC_BOOT}}} some additional mmc commands are available:
     129 * mmc bootbus <dev> <boot_bus_width> <reset_boot_bus_width> <boot_mode>
     130 * mmc bootpart-resize <dev> <boot-part-size-mb> <rpmb-part-size-mb>
     131 * mmc partconf <dev> <boot_ack> <boot-partition> <partition-access> # set PARTITION_CONFIG field
     132 * mmc rst-function <dev> <value> # change RST_n_FUNCTION field between 0|1|2 (write-once)
     133
     134The {{{mmc partconf}}} command can be used to configure the PARTITION_CONFIG specifying what hardware partition to boot from:
     135{{{#!bash
     136mmc partconf 0 0 0 0 # disable boot partition (default unset condition; boots from user partition)
     137mmc partconf 0 1 1 0 # set boot0 partition (with ack)
     138mmc partconf 0 1 2 0 # set boot1 partition (with ack)
     139mmc partconf 0 1 7 0 # set user partition (with ack)
     140}}}
     141
     142If U-Boot has been built with {{{CONFIG_SUPPORT_EMMC_RPMB}}} the {{{mmc rpmb}}} command is available for reading, writing and programming the key for the Replay Protection Memory Block (RPMB) partition in eMMC.
     143
     144When using U-Boot to write to eMMC (or microSD) it is often useful to use the {{{gzwrite}}} command. For example if you have a compressed 'disk image' you can write it to your eMMC (assuming it is mmc dev 0) with:
     145{{{#!bash
     146tftpboot ${loadaddr} disk-image.gz && gzwrite mmc 0 ${loadaddr} ${filesize}
     147}}}
     148 * The {{{disk-image.gz}}} contains a partition table at offset 0x0 as well as partitions at their respective offsets (according to the partition table) and has been compressed with gzip
     149 * If you know the flash offset of a specific partition (which you can determine using the {{{part list mmc 0}}} command) you can also use gzwrite to flash a compressed partition image
     150
     151
     152[=#emmc-linux]
     153==== Linux Support
     154Linux presents the various hardware partitions as separate devices:
     155 - /dev/mmcblk0boot0 - BOOT0 partition
     156 - /dev/mmcblk0boot1 - BOOT1 partition
     157 - /dev/mmcblk0rpmb - RPMB partition
     158 - /dev/mmcblk0 - USER partition
     159
     160Note that the BOOT partitions by default are read-only as they are typically used for sensitive boot firmware. To write to them you can disable {{{force_ro}}} in sysfs via:
     161{{{#!bash
     162echo 0 > /sys/class/block/mmcblk0boot0/force_ro
     163}}}
     164
     165The Linux {{{mmc}}} application from the {{{mmc-utils}}} package provides access to eMMC configuration through CSD registers.
     166
     167You can use the {{{mmc}}} utility to configure the eMMC PARTITION_CONFIG to specify the boot device on power-up via {{{mmc bootpart enable <boot_partition> <send_ack> <device>}}} where boot_partition specifies the hardware partition (1=boot0, 2=boot1, 7=user), send_ack specifies the device must send an awknoledgement (for fast boot), and device is the root mmc block device of the eMMC:
     168{{{#!bash
     169# set boot partition to boot0
     170mmc bootpart enable 1 0 /dev/mmcblk0
     171# set boot partition to boot1
     172mmc bootpart enable 2 0 /dev/mmcblk0
     173# set boot partition to user
     174mmc bootpart enable 7 0 /dev/mmcblk0
     175}}}
     176
     177Some additional use cases:
     178{{{#!bash
     179# show PARTITION_CONFIG:
     180mmc extcsd read /dev/mmcblk0 | grep PARTITION_CONFIG
     181# show BUS CONFIG:
     182mmc extcsd read /dev/mmcblk0 | grep BOOT_BUS_CONDITIONS
     183# disable boot partition
     184mmc bootpart enable 0 0 /dev/mmcblk0
     185}}}
     186
     187References:
     188 * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/mmc/mmc-tools.txt
     189
    116190
    117191[=#emmc-enhanced-user-area]
     
    240314- if you change the configuration of your boot area you must re-program the eMMC via JTAG
    241315
    242 [=#emmc-uboot]
    243 === U-Boot Support ===
    244 U-Boot provides access to eMMC devices through the {{{mmc}}} command and interface but adds an additional argument to the {{{mmc}}} interface to describe the hardware partition. The interface is therefore described as 'mmc <dev> <part>' where 'dev' is the mmc device (some boards have more than one) and 'part' is the hardware partition: 0=user, 1=boot0, 2=boot1.
    245 
    246 Use the {{{mmc dev}}} command to specify the device and partition:
    247 {{{#!bash
    248 mmc dev 0 0 # select user hw partition
    249 mmc dev 0 1 # select boot0 hw partition
    250 mmc dev 0 2 # select boot1 hw partition
    251 }}}
    252 
    253 If U-Boot has been built with {{{CONFIG_SUPPORT_EMMC_BOOT}}} some additional mmc commands are available:
    254  * mmc bootbus <dev> <boot_bus_width> <reset_boot_bus_width> <boot_mode>
    255  * mmc bootpart-resize <dev> <boot-part-size-mb> <rpmb-part-size-mb>
    256  * mmc partconf <dev> <boot_ack> <boot-partition> <partition-access> # set PARTITION_CONFIG field
    257  * mmc rst-function <dev> <value> # change RST_n_FUNCTION field between 0|1|2 (write-once)
    258 
    259 The {{{mmc partconf}}} command can be used to configure the PARTITION_CONFIG specifying what hardware partition to boot from:
    260 {{{#!bash
    261 mmc partconf 0 0 0 0 # disable boot partition (default unset condition; boots from user partition)
    262 mmc partconf 0 1 1 0 # set boot0 partition (with ack)
    263 mmc partconf 0 1 2 0 # set boot1 partition (with ack)
    264 mmc partconf 0 1 7 0 # set user partition (with ack)
    265 }}}
    266 
    267 If U-Boot has been built with {{{CONFIG_SUPPORT_EMMC_RPMB}}} the {{{mmc rpmb}}} command is available for reading, writing and programming the key for the Replay Protection Memory Block (RPMB) partition in eMMC.
    268 
    269 When using U-Boot to write to eMMC (or microSD) it is often useful to use the {{{gzwrite}}} command. For example if you have a compressed 'disk image' you can write it to your eMMC (assuming it is mmc dev 0) with:
    270 {{{#!bash
    271 tftpboot ${loadaddr} disk-image.gz && gzwrite mmc 0 ${loadaddr} ${filesize}
    272 }}}
    273  * The {{{disk-image.gz}}} contains a partition table at offset 0x0 as well as partitions at their respective offsets (according to the partition table) and has been compressed with gzip
    274  * If you know the flash offset of a specific partition (which you can determine using the {{{part list mmc 0}}} command) you can also use gzwrite to flash a compressed partition image
    275 
    276 
    277 [=#emmc-linux]
    278 === Linux Support ===
    279 Linux presents the various hardware partitions as separate devices:
    280  - /dev/mmcblk0boot0 - BOOT0 partition
    281  - /dev/mmcblk0boot1 - BOOT1 partition
    282  - /dev/mmcblk0rpmb - RPMB partition
    283  - /dev/mmcblk0 - USER partition
    284 
    285 Note that the BOOT partitions by default are read-only as they are typically used for sensitive boot firmware. To write to them you can disable {{{force_ro}}} in sysfs via:
    286 {{{#!bash
    287 echo 0 > /sys/class/block/mmcblk0boot0/force_ro
    288 }}}
    289 
    290 The Linux {{{mmc}}} application from the {{{mmc-utils}}} package provides access to eMMC configuration through CSD registers.
    291 
    292 You can use the {{{mmc}}} utility to configure the eMMC PARTITION_CONFIG to specify the boot device on power-up via {{{mmc bootpart enable <boot_partition> <send_ack> <device>}}} where boot_partition specifies the hardware partition (1=boot0, 2=boot1, 7=user), send_ack specifies the device must send an awknoledgement (for fast boot), and device is the root mmc block device of the eMMC:
    293 {{{#!bash
    294 # set boot partition to boot0
    295 mmc bootpart enable 1 0 /dev/mmcblk0
    296 # set boot partition to boot1
    297 mmc bootpart enable 2 0 /dev/mmcblk0
    298 # set boot partition to user
    299 mmc bootpart enable 7 0 /dev/mmcblk0
    300 }}}
    301 
    302 Some additional use cases:
    303 {{{#!bash
    304 # show PARTITION_CONFIG:
    305 mmc extcsd read /dev/mmcblk0 | grep PARTITION_CONFIG
    306 # show BUS CONFIG:
    307 mmc extcsd read /dev/mmcblk0 | grep BOOT_BUS_CONDITIONS
    308 # disable boot partition
    309 mmc bootpart enable 0 0 /dev/mmcblk0
    310 }}}
    311 
    312 References:
    313  * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/mmc/mmc-tools.txt
    314 
    315316
    316317[=#microsd]