I've been playing with passing some data from first to second stage using Jan's patches.
It worked fine, but in my case I want to store this data on a global variable, which is cleared as it's in the BSS.
There is a clean workarround to this issue?
Thanks,
Vicente.
On Wed, Sep 26, 2012 at 9:45 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
If I understand correctly the first stage loader puts some data hereOn Wed, Sep 26, 2012 at 12:59:51AM +0200, vj wrote:
> ---
> arch/arm/cpu/cpu.c | 1 +
> arch/arm/lib/barebox.lds.S | 10 +
> arch/arm/mach-omap/Kconfig | 21 +
> arch/arm/mach-omap/Makefile | 1 +
> arch/arm/mach-omap/include/mach/omap4_rom_usb.h | 146 +++++
> arch/arm/mach-omap/omap4_generic.c | 2 +
> arch/arm/mach-omap/omap4_rom_usb.c | 189 ++++++
> arch/arm/mach-omap/xload.c | 26 +
> scripts/.gitignore | 1 +
> scripts/Makefile | 3 +
> scripts/usbboot.c | 797 ++++++++++++++++++++++++
> 11 files changed, 1197 insertions(+)
> create mode 100644 arch/arm/mach-omap/include/mach/omap4_rom_usb.h
> create mode 100644 arch/arm/mach-omap/omap4_rom_usb.c
> create mode 100644 scripts/usbboot.c
>
> diff --git a/arch/arm/cpu/cpu.c b/arch/arm/cpu/cpu.c
> index 71ef8c0..05343de 100644
> --- a/arch/arm/cpu/cpu.c
> +++ b/arch/arm/cpu/cpu.c
> @@ -89,6 +89,7 @@ void arch_shutdown(void)
> : "r0", "r1", "r2", "r3", "r6", "r10", "r12", "lr", "cc", "memory"
> );
> #endif
> + __asm__ __volatile__ ("cpsid i\n");
> }
>
> #ifdef CONFIG_THUMB2_BAREBOX
> diff --git a/arch/arm/lib/barebox.lds.S b/arch/arm/lib/barebox.lds.S
> index a69013f..ff7b63d 100644
> --- a/arch/arm/lib/barebox.lds.S
> +++ b/arch/arm/lib/barebox.lds.S
> @@ -97,6 +97,16 @@ SECTIONS
> __bss_start = .;
> .bss : { *(.bss*) }
> __bss_stop = .;
> +#ifdef CONFIG_SHARE_USB_HANDLE
> + /*
> + * Reserve space for the USB handle
> + */
> + . = CONFIG_USB_HANDLE_HANDOVER;
> + . = ALIGN(4);
> + __usb_handle = .;
> + /* . += sizeof(struct usb); */
> + . += 84;
> +#endif
where a second stage barebox (configured with the same value for
CONFIG_USB_HANDLE_HANDOVER) will pick it up.
This seems to be a bit fragile. Fortunately Jan has posted a series
that gives the control of the reset vector to the boards, which means
that both stages do not have to agree on an addres, but instead a
pointer can be passed from the first to the second stage.
> +int usb_open(void)
So this uses the OMAP4 ROM to do USB communication, right? The functions
should have a omap_rom_* prefix then, otherwise it's not clear for a
reader which context these functions have.
The calling of the ROM code btw explains why the setting of VBAR breaks
USB boot. The ROM probably uses the vectors.
You can add the following to CONFIG_OMAP4_USB_BOOT instead:
> +
> + n = rom_get_per_driver(&pusb->io, boot->device_type);
> + if (n)
> + return n;
> +
> + pusb->dread.xfer_mode = boot->xfer_mode;
> + pusb->dread.options = boot->options;
> + pusb->dread.device_type = boot->device_type;
> +
> + pusb->dwrite.xfer_mode = boot->xfer_mode;
> + pusb->dwrite.options = boot->options;
> + pusb->dwrite.device_type = boot->device_type;
> +#else
> +#ifdef CONFIG_MMU
> +#error USB communications not working under MMU
depends on !MMU
So that an invalid config is not allowed in the first place.
> diff --git a/scripts/usbboot.c b/scripts/usbboot.c
This should also be named omap4-usbboot.c, or maybe, if the works on
other OMAPs, just omap-usboot.c
Sascha
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