CODEWITHSUNDEEP
linuxlinux-device-driverembedded-linuxdevice-driver
Aivars
Aivars

Reputation: 93

How to change MTD device serial number?

I have embedded system with some MTD devices and added one more MTD device (SPI flash). This new device now is mtd0 and number for all previous MTD devices are +1. How can I assign MTD device number for this new driver to keep numbers of previous MTD devices unchanged ?

Before:

# cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00100000 00020000 "u-boot"
...

After:

# cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00100000 00001000 "spi-nor-flash"
mtd1: 00100000 00020000 "u-boot"
...

I want to achieve:

# cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00100000 00020000 "u-boot"
...
mtd5: 00100000 00001000 "spi-nor-flash"

Upvotes: 0

Views: 1972

Answers (3)

Aivars
Aivars

Reputation: 93

Possible workaround: make SPI flash driver as loadable module and load it after system booting:

/ # cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00800000 00020000 "u-boot"
...
mtd4: 0c8c0000 00020000 "ubipart"

/ # insmod m25p80.ko
[  365.735184] m25p80 spi0.0: n25q256a (32768 Kbytes)
[  365.739903] 1 ofpart partitions found on MTD device spi0.0
[  365.745396] Creating 1 MTD partitions on "spi0.0":
[  365.750133] 0x000000000000-0x000000800000 : "spi-flash"

/ # cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00800000 00020000 "u-boot"
...
mtd4: 0c8c0000 00020000 "ubipart"
mtd5: 00800000 00001000 "spi-flash"

Upvotes: 0

Lev U.
Lev U.

Reputation: 181

You may specify MTD partition numbers in the device tree source file (or in the board .c file if your kernel doesn't use DTB). You need something like this:

&spi0{
    status = "okay";
    pinctrl-names = "default";
    pinctrl-0 = <&spi0_pins>;
    /* DO is MOSI, D1 is MISO */
    /*ti,pindir-d0-out-d1-in = <0>;*/
    m25p80@0 {
            #address-cells = <1>;
            #size-cells = <1>;
            compatible = "st,m25pe80";
            reg = <0>;
            spi-max-frequency = <1000000>;
            /*m25p,fast-read;*/
             partition@12 {
                            label = "spi-nor-spl1";
                            reg = <0x0 0x20000>; /* 128k */
                    };

    };
};

(example taken from here) for SPI flash and other devices with MTD partitions.

Upvotes: 1

Frank Meerk&#246;tter
Frank Meerk&#246;tter

Reputation: 2858

I suggest to have a look at this article https://wiki.archlinux.org/index.php/persistent_block_device_naming . Udev can help you name block devices without relying on the order the devices are discovered.

Upvotes: 1

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