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mtd block readonly low level nand driver cramfs

DISCUSSION Max Stirling 1 participant 4 messages Jan 24, 2008 – Jan 30, 2008 Memory technology devices (MTD)

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Max Stirling

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#0 lore raw

Hi,

This might sound quite basic question. This is the first time I am looking into the MTD code so have some really basic questions.

I am trying to mount a read only fs (cramfs) on the flash. Please let me know if the following steps are right:

1. Enabled the following in the Kconfig files
CONFIG_MTD_PARITIONS
CONFIG_MTD
CONFIG_MTD_BLOCK_RO
CONFIG_MTD_NAND
CONFIG_MTD_NAND_IDS

After booting the compiled kernel I am able to see the mtdblock under /proc/devices using 31 Major number.

Now for me to mount the cramfs image that is on the flash I need to provide the low level nand driver code. This I need to write but before starting that can any one point me to a reference nand driver code that is used for read only mount? Which functionality would the MTD require to be implemented for mounting a cramfs image which is on the flash.

Would appreciate any pointers to how to get started off with this.

thanks in advance for the reply.

M.S

author
#1 lore raw

I was looking at the chips folder under MTD and the MTD_ROM flag settings.

I got this idea of having this low level driver code under chips with the MTD_ROM flag set and mounting this for cramfs.

Please comment, especially folks using the RO FS mounted on flash.

MS

Quoted 32 lines · Max Stirling

Hi,

This might sound quite basic question. This is the first time I am looking into the MTD code so have some really basic questions.

I am trying to mount a read only fs (cramfs) on the flash. Please let me know if the following steps are right:

1. Enabled the following in the Kconfig files
CONFIG_MTD_PARITIONS
CONFIG_MTD
CONFIG_MTD_BLOCK_RO
CONFIG_MTD_NAND
CONFIG_MTD_NAND_IDS

After booting the compiled kernel I am able to see the mtdblock under /proc/devices using 31 Major number.

Now for me to mount the cramfs image that is on the flash I need to provide the low level nand driver code. This I need to write but before starting that can any one point me to a reference nand driver code that is used for read only mount? Which functionality would the MTD require to be implemented for mounting a cramfs image which is on the flash.

Would appreciate any pointers to how to get started off with this.

thanks in advance for the reply.

M.S

author
#2 lore raw
Quoted 44 lines · Max Stirling

I was looking at the chips folder under MTD and the MTD_ROM flag settings.

I got this idea of having this low level driver code under chips with the MTD_ROM flag set and mounting this for cramfs.

Please comment, especially folks using the RO FS mounted on flash.

MS

Quoted 33 lines · Max Stirling

Hi,

This might sound quite basic question. This is the first time I am looking into the MTD code so have some really basic questions.

I am trying to mount a read only fs (cramfs) on the flash. Please let me know if the following steps are right:

1. Enabled the following in the Kconfig files
CONFIG_MTD_PARITIONS
CONFIG_MTD
CONFIG_MTD_BLOCK_RO
CONFIG_MTD_NAND
CONFIG_MTD_NAND_IDS

After booting the compiled kernel I am able to see the mtdblock under /proc/devices using 31 Major number.

Now for me to mount the cramfs image that is on the flash I need to provide the low level nand driver code. This I need to write but before starting that can any one point me to a reference nand driver code that is used for read only mount? Which functionality would the MTD require to be implemented for mounting a cramfs image which is on the flash.

Would appreciate any pointers to how to get started off with this.

thanks in advance for the reply.

M.S

When using the cramfs as the fs for the flash and mtdblock_ro enabled. Which one should I be calling the user module, the cramfs or the mtdblock_ro?

author
#3 lore raw
Quoted 39 lines · Max Stirling
Quoted 38 lines · Max Stirling

I was looking at the chips folder under MTD and the MTD_ROM flag settings.

I got this idea of having this low level driver code under chips with the MTD_ROM flag set and mounting this for cramfs.

Please comment, especially folks using the RO FS mounted on flash.

MS

Quoted 27 lines · Max Stirling

Hi,

This might sound quite basic question. This is the first time I am looking into the MTD code so have some really basic questions.

I am trying to mount a read only fs (cramfs) on the flash. Please let me know if the following steps are right:

1. Enabled the following in the Kconfig files
CONFIG_MTD_PARITIONS
CONFIG_MTD
CONFIG_MTD_BLOCK_RO
CONFIG_MTD_NAND
CONFIG_MTD_NAND_IDS

After booting the compiled kernel I am able to see the mtdblock under /proc/devices using 31 Major number.

Now for me to mount the cramfs image that is on the flash I need to provide the low level nand driver code. This I need to write but before starting that can any one point me to a reference nand driver code that is used for read only mount? Which functionality would the MTD require to be implemented for mounting a cramfs image which is on the flash.

Would appreciate any pointers to how to get started off with this.

Quoted 9 lines
Quoted 6 lines
Quoted 6 lines

thanks in advance for the reply.

M.S

When using the cramfs as the fs for the flash and mtdblock_ro enabled. Which one should I be calling the user module, the cramfs or the mtdblock_ro?

I have enabled the mtdblock_ro module and written a low lever chip driver code. Since I am mounting this as read-only I have set the type in mtd_info to MTD_ROM.

When I do a mount using command

# mount -t cramfs /dev/mtdblock mnt_cramfs
.
mtdblock_ro.c mtdblock_readsect
mtdblock_ro.c mtdblock_readsect
mtdblock_ro.c mtdblock_readsect
mtdblock_ro.c mtdblock_readsect
.
mount: Mounting /dev/mtdblock on cramfs failed: Invalid argument.

I created a cramfs image using cramfs utility and written that to flash. I tested the cramfs image by mounting on my local machine.

Is there anything that is missing here?

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