i.MX31 3DS board not booting after commit 1c2f87c22... ARM: 8025/1: Get rid of meminfo

[Magnus Lilja]

Hi,

I'm trying to get current modern Linux kernels to boot on the i.MX31 PDK 
board (a.k.a MX31_3DS).

One problem I've noticed is that I have to comment out the following 
code from mach-mx31_3ds.c, the reserve function is registered as 
mach_desc->reserve . If I leave this function as is the kernel stops 
very early in the boot (see end of the mail).

static void __init mx31_3ds_reserve(void)
{
	/* reserve MX31_3DS_CAMERA_BUF_SIZE bytes for mx3-camera */
	mx3_camera_base = arm_memblock_steal(MX31_3DS_CAMERA_BUF_SIZE,
					 MX31_3DS_CAMERA_BUF_SIZE);
}

The commits that causes this problem (according to git bisect) is:
[1c2f87c22566cd057bc8cde10c37ae9da1a1bb76] ARM: 8025/1: Get rid of meminfo

(Yes, it's been a while since I last tried to boot a modern kernel on 
this board)

I'm using the imx_v6_v7_defconfig.

Kernel boot log using earlyprintk. (the arm_memblock_init NNN lines are 
my added printk's)

Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.0-rc7-dirty (lilja at xubuntu-14-04) (gcc 
version 4. 8.3 20140320 (prerelease) (Sourcery CodeBench Lite 
2014.05-29) ) #150 SMP Sun Dec 11 11:12:32 CET 2016
[    0.000000] CPU: ARMv6-compatible processor [4107b364] revision 4 
(ARMv6TEJ), cr=00c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing 
instruction cache
[    0.000000] Machine: Freescale MX31PDK (3DS)
[    0.000000] bootconsole [earlycon0] enabled
[    0.000000] arm_memblock_init 268
[    0.000000] arm_memblock_init 273
[    0.000000] arm_memblock_init 277
[    0.000000] cma: Reserved 16 MiB at 0x86800000
[    0.000000] arm_memblock_init 281
[    0.000000] Memory policy: Data cache writeback
[    0.000000] CPU: All CPU(s) started in SVC mode.
[    0.000000] percpu: Embedded 14 pages/cpu @c64f0000 s26688 r8192 
d22464 u57344
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on. 
Total pages: 30464
[    0.000000] Kernel command line: console=ttymxc0,115200 earlyprintk
[    0.000000] PID hash table entries: 512 (order: -1, 2048 bytes)
[    0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 
bytes)
[    0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)

This is where boot stops. If I comment out the arm_memblock_steal() call 
from mx31_3ds_reserve() the boot works and the next couple of lines are:

[    0.000000] Memory: 92564K/131072K available (8192K kernel code, 360K 
rwdata, 2 280K rodata, 1024K init, 8218K bss, 22124K reserved, 16384K 
cma-reserved, 0K highmem)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
[    0.000000]     vmalloc : 0xc8800000 - 0xff800000   ( 880 MB)
[    0.000000]     lowmem  : 0xc0000000 - 0xc8000000   ( 128 MB)
[    0.000000]     pkmap   : 0xbfe00000 - 0xc0000000   (   2 MB)
[    0.000000]     modules : 0xbf000000 - 0xbfe00000   (  14 MB)
[    0.000000]       .text : 0xc0008000 - 0xc0900000   (9184 kB)
[    0.000000]       .init : 0xc0c00000 - 0xc0d00000   (1024 kB)
[    0.000000]       .data : 0xc0d00000 - 0xc0d5a120   ( 361 kB


I have really no clue why that commit causes problems. There are not a 
lot of boards using mach_desc->reserve .

Any ideas on how to fix or debug this?

Regards, Magnus