[U-Boot] [RFC PATCH v2] ARM: Avoid compiler optimization for usages of readb, writeb and friends.

[John Rigby]

On Mon, Dec 20, 2010 at 10:12 AM, Alexander Holler <holler at ahsoftware.de> wrote:

> There must be more problems. Using gcc 4.5.1, the read*/write*-patch and
> your hack, my kernel doesn't boot. Using gcc 4.3.5 and the same source to
> compile u-boot the kernel comes up. Here is the output for the non-working
> u-boot:
>
> ----------------
> U-Boot 2010.12-rc3-00015-g3ae9687-dirty (Dec 20 2010 - 18:01:41, gcc 4.5.1)
>
> OMAP3530-GP ES3.1, CPU-OPP2, L3-165MHz, Max CPU Clock 720 mHz
> OMAP3 Beagle board + LPDDR/NAND
> I2C:   ready
> DRAM:  256 MiB
> NAND:  256 MiB
> MMC:   OMAP SD/MMC: 0
> In:    serial
> Out:   serial
> Err:   serial
> Beagle Rev C4
> timed out in wait_for_pin: I2C_STAT=0
> No EEPROM on expansion board
> Die ID #062a000400000000040365fa16019019
> Hit any key to stop autoboot:  0
> reading boot.scr
>
> 422 bytes read
> Running bootscript from mmc ...
> ## Executing script at 82000000
> reading uImage
>
> 2419940 bytes read
> Booting from mmc ...
> ## Booting kernel from Legacy Image at 82000000 ...
>   Image Name:   Linux-2.6.37-rc5-beagleboard-000
>   Image Type:   ARM Linux Kernel Image (uncompressed)
>   Data Size:    2419876 Bytes = 2.3 MiB
>   Load Address: 80008000
>   Entry Point:  80008000
>   Verifying Checksum ... OK
>   Loading Kernel Image ... OK
> OK
> ----------------
>
> Nothing else.
>
> Regards,
>
> Alexander
>

Yes, you are correct, I see the same here with 4.5.2.  I noticed that
bd did not have correct values of machine type and boot params:

bd address  = 0x8FF24FE0
arch_number = 0xFF0084FF
boot_params = 0xBB2000FE
DRAM bank   = 0x00000000
-> start    = 0x80000000
-> size     = 0x08000000
DRAM bank   = 0x00000001
-> start    = 0x88000000
-> size     = 0x08000000
baudrate    = 115200 bps
TLB addr    = 0x8FFF0000
relocaddr   = 0x8FF85000
reloc off   = 0x0FF7D000
irq_sp      = 0x8FF24F68
sp start    = 0x8FF24F60
FB base     = 0x00000000

If we then look at board_init in beagle.c the problem is obvious:

800331ac <board_init>:
800331ac:       e92d4008        push    {r3, lr}
800331b0:       ebff5a74        bl      80009b88 <gpmc_init>
800331b4:       e3a00000        mov     r0, #0
800331b8:       e5983000        ldr     r3, [r8]
800331bc:       e5983000        ldr     r3, [r8]
800331c0:       e8bd8008        pop     {r3, pc}

Here is with source mingled in:
800331ac <board_init>:
/*
 * Routine: board_init
 * Description: Early hardware init.
 */
int board_init(void)
{
800331ac:       e92d4008        push    {r3, lr}
        DECLARE_GLOBAL_DATA_PTR;

        gpmc_init(); /* in SRAM or SDRAM, finish GPMC */
800331b0:       ebff5a74        bl      80009b88 <gpmc_init>
        gd->bd->bi_arch_number = MACH_TYPE_OMAP3_BEAGLE;
        /* boot param addr */
        gd->bd->bi_boot_params = (OMAP34XX_SDRC_CS0 + 0x100);

        return 0;
}
800331b4:       e3a00000        mov     r0, #0
{
        DECLARE_GLOBAL_DATA_PTR;

        gpmc_init(); /* in SRAM or SDRAM, finish GPMC */
        /* board id for Linux */
        gd->bd->bi_arch_number = MACH_TYPE_OMAP3_BEAGLE;
800331b8:       e5983000        ldr     r3, [r8]
        /* boot param addr */
        gd->bd->bi_boot_params = (OMAP34XX_SDRC_CS0 + 0x100);
800331bc:       e5983000        ldr     r3, [r8]

        return 0;
}
800331c0:       e8bd8008        pop     {r3, pc}

br,

John