Re: mcf54415, spi nor and SD drivers

[Greg Ungerer <gregungerer@westnet.com.au>]

Hi Angelo,

On 06/07/17 18:36, angelo wrote:
> i designed here a new board with mcf54415. Testing a first mainline kernel.
> I would like to load a cramfs rootfs from SPI NOR (mtd, ftl) but actually
> i don't see the SPI NOR flash detected from dmesg.
> 
> Next future step then would be load rootfs from SD.
> 
> Seems there is no selectable driver for
> 
> - SPI controller
> - SD (MMC) controller
> 
> Those should be similar to existing drivers of some other freescale chip,
> or some new implementation is required ? Attaching dmesg.

Most other ColdFire parts use the QSPI hardware module, and its driver
is at drivers/spi/spi-coldfire-qspi.c. But, looking at the hardware
reference manual for the mcf5441x family it contains a DSPI hardware
module - and it looks quite different.

That DSPI module looks to be similar to the one in the Freescale iMX
parts, and its driver is at drivers/spi/spi-fsl-dspi.c. I don't know
that anyone has used that on ColdFire with the mcf5441x parts,
but that is where you should start I think.

I haven't used any SD/MMC drivers on ColdFire so no advice on where
to look for that one.

If you are feeling adventurous you may want to look at:

   https://www.spinics.net/lists/linux-m68k/msg10057.html

With a reasonably recent kernel you don't even need to generate a
different user space filesystem and binaries. You can run your flat
format non-MMU binaries on an MMU configured ColdFire system (as long
as you have CONFIG_BINFMT_FLAT=y in your kernel config). I would love
to be able to push this patch to mainline.

Regards
Greg



> Regards,
> Angelo Dureghello
> 
> 
> U-Boot 2017.05-00709-g9d9f074dfe-dirty (Jul 02 2017 - 19:50:16 +0200)
> 
> CPU:   Freescale MCF54410 (Mask:9f Version:2)
>         CPU CLK 240 MHz BUS CLK 120 MHz FLB CLK 60 MHz
>         INP CLK 30 MHz VCO CLK 480 MHz
> SPI:   ready
> DRAM:  128 MiB
> SF: Detected is25lp128 with page size 256 Bytes, erase size 64 KiB, 
> total 16 MiB
> In:    serial
> Out:   serial
> Err:   serial
> Hit any key to stop autoboot:  0
> SF: Detected is25lp128 with page size 256 Bytes, erase size 64 KiB, 
> total 16 MiB
> device 0 offset 0x100000, size 0x200000
> SF: 2097152 bytes @ 0x100000 Read: OK
> ## Booting kernel from Legacy Image at 40001000 ...
>     Image Name:   mainline kernel
>     Created:      2017-07-05  23:58:53 UTC
>     Image Type:   M68K Linux Kernel Image (uncompressed)
>     Data Size:    1642496 Bytes = 1.6 MiB
>     Load Address: 40001000
>     Entry Point:  40001000
>     Verifying Checksum ... OK
>     Loading Kernel Image ... OK
> [    0.000000] Linux version 4.10.0-rc2stmark2-001-00020-g0f64df301240 
> (angelo@jerusalem) (gcc version 4.9.0 (crosstools-sysam-2016.04.16) ) 
> #16 Thu Jul 6 01:58:52 CEST 2017
> [    0.000000] uClinux with CPU COLDFIRE(m5441x)
> [    0.000000] COLDFIRE port done by Greg Ungerer, gerg@snapgear.com
> [    0.000000] Flat model support (C) 1998,1999 Kenneth Albanowski, D. 
> Jeff Dionne
> [    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  
> Total pages: 16320
> [    0.000000] Kernel command line: console=ttyS0,115200 
> root=/dev/mtdblock3 mtdparts=spi-flash.0:1m(u-boot),7m(kernel),-(rootfs) 
> rw rootwait
> [    0.000000] PID hash table entries: 512 (order: -2, 2048 bytes)
> [    0.000000] Dentry cache hash table entries: 16384 (order: 3, 65536 
> bytes)
> [    0.000000] Inode-cache hash table entries: 8192 (order: 2, 32768 bytes)
> [    0.000000] Memory: 128664K/131072K available (1154K kernel code, 92K 
> rwdata, 304K rodata, 48K init, 121K bss, 2408K reserved, 0K cma-reserved)
> [    0.000000] Virtual kernel memory layout:
> [    0.000000]     vector  : 0x40000000 - 0x40000400   (   1 KiB)
> [    0.000000]     kmap    : 0x00000000 - 0xffffffff   (4095 MiB)
> [    0.000000]     vmalloc : 0x00000000 - 0xfffff ----- Message 
> truncated -----
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