write partition(s) to F-RAM fm25v01a-g

[ArRi_4326921]

Hello folks,

I am currently working on an embedded linux module based on Raspbian mounting on-board the F-RAM in the object :

https://www.cypress.com/part/fm25v01a-g

So as suggested here :

F-RAM Support under Linux – KBA223028

and here :

where can I find FM25V02 FRAM Linux Driver

I place this entry for the FRAM in the spi-nor.c source file of my kernel

{ "fm25v01a",  INFO(0x7f7f7f, 0, 16, 1024, 0) },

since the overall size of the memory is 16K. So, after cross-building the module and reloading at the next boot, I am able to the device with

$ cat /proc/mtd

dev:    size erasesize  name

mtd0: 00080000 00000200 "spi0.1"

so the next step I try is to use fdisk to create a partition as usual (my choice of filesystem type is FAT12) but when i try to write the changes I can't simply do it...any pointers for that ?

$ fdisk /dev/mtd0   

Welcome to fdisk (util-linux 2.29.2).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Device does not contain a recognized partition table.

Created a new DOS disklabel with disk identifier 0x5638c96c.

Command (m for help): p

Disk /dev/mtd0: 0 B, 0 bytes, 0 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disklabel type: dos

Disk identifier: 0x5638c96c

Command (m for help): n

Partition type

   p   primary (0 primary, 0 extended, 4 free)

   e   extended (container for logical partitions)

Select (default p): p

Partition number (1-4, default 1):

First sector (1-4294967295, default 1):

Last sector, +sectors or +size{K,M,G,T,P} (1-4294967294, default 4294967294): +5K

Created a new partition 1 of type 'Linux' and of size 5.5 KiB.

Command (m for help): t

Selected partition 1

Partition type (type L to list all types): 1

Changed type of partition 'Linux' to 'FAT12'.

Command (m for help): w

The partition table has been altered.

/dev/mtd0: close device failed: Invalid argument

thanks in advance !

           Arturo

[GernotH_31]

Hi Arturo,

you cannot partition a mtd with fdisk like you do with a hard disk, this is not supported. However, what you can do is, you can define mtd partitions as usual and then run a FAT on just one mtd partition.

It is preferable to define the F-RAM sector layout with 512 bytes sectors. This way it nicely corresponds to the usual 512 bytes sectors of disks. Then you can run a FAT as follows.

Best regards,

Gernot

# cat /proc/mtd

dev: size   erasesize  name

mtd0: 00080000 00000200 "spi0.0"

# mkfs.vfat /dev/mtdblock0

mkfs.fat 3.0.28 (2015-05-16)

unable to get drive geometry, using default 255/63

# mount -t vfat /dev/mtdblock0 /tt

# echo "Hello world!" > /tt/hello.txt

# umount /tt

# mount -t vfat /dev/mtdblock0 /tt

# ls -l /tt

total 2

-rwxr-xr-x 1 root root 13 Feb  5 11:13 hello.txt

[ArRi_4326921]

Hello Gernot,

I just run this command :

# mkfs.vfat /dev/mtd0  

mkfs.fat 4.1 (2017-01-24)

mkfs.vfat: unable to discover size of /dev/mtd0

since in my case the device is /dev/mtd0 but I get that message error, any pointers ?

# ls -l /dev/ | grep mtd

crw------- 1 root root     90,   0 Jun 28 10:51 mtd0

crw------- 1 root root     90,   1 Jun 28 10:51 mtd0ro

this are just the mounted devices belonging to the mtd group.

           Kind Regards

[GernotH_31]

Hi Arturo,

you need to enable the mtdblock driver in the kernel configuration menu. Afterwards, you should get both /dev/mtdx character devices and /dev/mtdblockx block devices.

Best regards,

Gernot

[ArRi_4326921]

I have gone further....after manually loading the mtdblock.ko kernel module finally the device /dev/mtdblock0 pops up but I am unable to format the filesytem as you suggested :

# cat /proc/mtd

dev: size erasesize name

mtd0: 00004000 00000010 "spi0.1"

# mkfs.vfat /dev/mtdblock0

mkfs.fat 4.1 (2017-01-24)

attribute "partition" not found

mkfs.vfat: Device partition expected, not making filesystem on entire device '/dev/mtdblock0' (use -I to override)

# mkfs.vfat -I /dev/mtdblock0

mkfs.fat 4.1 (2017-01-24)

attribute "partition" not found

mkfs.vfat: Attempting to create a too large filesystem

any pointers ?

[GernotH_31]

Your mtd size/erasesize does not look good. eraseisize seems to be set to 0x10=16!? Can you set the erasesize to 512 (0x200) and check again?

[ArRi_4326921]

The FRAM has an overall size of 16K, hence my spi-nor.c entry :

https://www.cypress.com/part/fm25v01a-gload&usg=AOvVaw1S3e-YB5-BR7JEZgCLtE5Y

more information about it

root@aranciarty:~# mtdinfo --map /dev/mtd0

mtd0

Name:                           spi0.1

Type:                           nor

Eraseblock size:                16 bytes

Amount of eraseblocks:          1024 (16384 bytes, 16.0 KiB)

Minimum input/output unit size: 1 byte

Sub-page size:                  1 byte

Character device major/minor:   90:0

Bad blocks are allowed:         false

Device is writable:             true

Eraseblock map:

maybe declaring one of these arguments :

#define SECT_4K BIT(0) /* SPINOR_OP_BE_4K works uniformly */

#define SPI_NOR_NO_ERASE BIT(1) /* No erase command needed */

#define SST_WRITE BIT(2) /* use SST byte programming */

#define SPI_NOR_NO_FR BIT(3) /* Can't do fastread */

#define SECT_4K_PMC BIT(4) /* SPINOR_OP_BE_4K_PMC works uniformly */

#define SPI_NOR_DUAL_READ BIT(5) /* Flash supports Dual Read */

#define SPI_NOR_QUAD_READ BIT(6) /* Flash supports Quad Read */

#define USE_FSR BIT(7) /* use flag status register */

#define SPI_NOR_HAS_LOCK BIT(8) /* Flash supports lock/unlock via SR */

#define SPI_NOR_HAS_TB BIT(9) /*

* Flash SR has Top/Bottom (TB) protect

* bit. Must be used with

* SPI_NOR_HAS_LOCK.

*/

#define SPI_S3AN BIT(10) /*

* Xilinx Spartan 3AN In-System Flash

* (MFR cannot be used for probing

* because it has the same value as

* ATMEL flashes)

*/

#define SPI_NOR_4B_OPCODES BIT(11) /*

* Use dedicated 4byte address op codes

* to support memory size above 128Mib.

*/

#define NO_CHIP_ERASE BIT(12) /* Chip does not support chip erase */

#define SPI_NOR_SKIP_SFDP BIT(13) /* Skip parsing of SFDP tables */

#define USE_CLSR BIT(14) /* use CLSR command */

might solve it ?

[ArRi_4326921]

Hello GernotH,

I rebuilt the module with this entries :

{ "fm25v01a",  INFO(0x7f7f7f, 0, 512, 32, 0) },

or, as an alternative :

{ "fm25v01a",    INFO(0x7f7f7f, 0, 512, 32, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_HAS_LOCK) },

so getting this output :

# mtdinfo -a

Count of MTD devices:          1

Present MTD devices:            mtd0

Sysfs interface supported:      yes

mtd0

Name:                          spi0.1

Type:                          nor

Eraseblock size:                512 bytes

Amount of eraseblocks:          32 (16384 bytes, 16.0 KiB)

Minimum input/output unit size: 1 byte

Sub-page size:                  1 byte

Character device major/minor:  90:0

Bad blocks are allowed:        false

Device is writable:            true

but the error still persists....any idea ?

BTW, which is your on-board FRAM and above all which are your kernel modifications ? It may help me a lot understanding the issue....

          Thanks in advance

[GernotH_31]

Another detail you need to consider is that this device requires 2 address bytes! This is different from the 3 or 4 address bytes that are usually used for flash memories in the driver. There are special macros available to specify that.

I have ordered some parts and will take a closer look at this when I have got them. Will keep you posted!

--Gernot

[ArRi_4326921]

Hello Gernot,

thank you for all the effort you are putting into this issue. I have really appreciated it.....looking forward to hear back from you as soon as you move on this behaviour.

Thank you very much again !

--Arturo

[GernotH_31 · Accepted solution]

Hi Arturo,

I have got samples now and checked the situation. Using the Cypress SPI memories driver (with support for 2 address bytes), I can reproduce the situation:

# ./mkfs.vfat  /dev/mtdblock0                                                                        

mkfs.fat 4.1 (2017-01-24)                                                                                       

mkfs.vfat: Attempting to create a too large filesystem

After analyzing the mkfs source code (mkfs.fat.c), I think the F-RAM device is too small for a FAT file system. This device has just 16 kByte, i.e. just 32 sectors of 512 bytes each. This is much less than a floppy disk had in the early days. FAT makes clusters of sectors and uses 2 FAT tables.

So I think you will have to move to a larger F-RAM density if you want to run a FAT on the device. I might run some tests here to find out the exact limit if you want.

Best regards,

Gernot