[PATCH 8/8] mx25 3ds: add support for boot from UART

[Baruch Siach]

Hi Sascha,

On Thu, Jun 10, 2010 at 02:12:08PM +0200, Sascha Hauer wrote:
> On Thu, Jun 10, 2010 at 02:49:39PM +0300, Baruch Siach wrote:
> > On Thu, Jun 10, 2010 at 01:12:37PM +0200, Sascha Hauer wrote:
> > > On Wed, Jun 09, 2010 at 10:05:07AM +0300, Baruch Siach wrote:
> > 
> > [snip]
> > 
> > > > --- a/board/freescale-mx25-3-stack/3stack.c
> > > > +++ b/board/freescale-mx25-3-stack/3stack.c
> > > > @@ -44,7 +44,11 @@ extern unsigned long _stext;
> > > >  
> > > >  void __naked __flash_header_start go(void)
> > > >  {
> > > > +#if defined CONFIG_FREESCALE_MX25_3STACK_UART_BOOT
> > > > +	__asm__ (".word	exception_vectors\n");
> > > > +#else
> > > >  	__asm__ __volatile__("b exception_vectors\n");
> > > > +#endif
> > > 
> > > Do we need this change? I booted other i.MX SoCs without it. I really
> > > like to keep this because it enables to jump to the first address if
> > > booting second stage.
> > 
> > This is actually a (very) short "flash" header with only the 
> > app_code_jump_vector entry left. Only reverse engineering the Freescale ATK 
> > software revealed this secret. Reading through the i.MX25 Reference Manual I 
> > now see that there is an option to pass DCD separately, but it complicates the 
> > boot sequence.  This change only affects builds when this configuration 
> > option, and this option is disabled by default.
> 
> What do you use to upload images?

I use a custom Perl script that parses a .inc file with the same syntax as the 
those distributed with the Freescale ATK. This script and the .inc file are 
attached.

> I once updated my favourite terminal program microcom 
> (git://git.pengutronix.de/git/tools/microcom) to be
> able to upload and start images. I didn't need any special images. I
> just used the ability to write registers to initialize the SDRAM and
> then uploaded an image to sdram with image type 0xaa which seems to
> just start the image at the given address.

What is this "given address"? Is this the same address as the image load 
address, i.e., the first instruction in the image?

> Find a log attached (which is on an i.MX27, but I tested it on i.MX35 and 
> i.MX51 aswell) Maybe this could be a solution for you aswell.

This could really simplify things. Is this support integrated in the git 
version of microcom?

Some more question below.

> Anyway, that said, I can apply your patch, too. I just find it very
> comfortable to use one image for all boot scenarios.
> 
> Sascha
> 
> sha at kiwi:~/octopus/microcom/microcom ./microcom -p /dev/ttyS0 -f
> connected to /dev/ttyS0
> Escape character: Ctrl-\
> Type the escape character followed by c to get to the menu or q to quit
> 
> barebox:/
> Enter command. Try 'help' for a list of builtin commands
> -> x b

Do you have Barebox running on the board at this point?
Is the above 'x b' a special microcom command, or a Barebox script?

I must say that Barebox is much more fun to work with than RedBoot. A huge 
improvement.

Thanks.

baruch

> mw 0xD8001010 0x00000004
> mw 0xD8001004 0x006ac73a
> mw 0xD8001000 0x92100000
> mw 0xA0000f00 0x12344321
> mw 0xD8001000 0xa2100000
> mw 0xA0000000 0x12344321
> mw 0xA0000000 0x12344321
> mw 0xD8001000 0xb2100000
> mwb 0xA0000033 0xda
> mwb 0xA1000000 0xff
> mw 0xD8001000 0x82226080
> mw 0xA0000000 0xDEADBEEF
> mw 0xD8001010 0x0000000c
> upload 0xa0000000 /home/sha/octopus/barebox/barebox/barebox-pcm038.bin 0xaa
> image type: 0xaa
> 
>     ################################################################
>     ################################################################
>     ########################################
> 
> ----------------------
> ����
> 
> barebox 2010.04.0-00140-g0a28ada-dirty (Apr 15 2010 - 11:40:21)
> 
> Board: Phytec phyCORE-i.MX27
> cfi_probe: cfi_flash base: 0xc0000000 size: 0x02000000
> NAND device: Manufacturer ID: 0x20, Chip ID: 0x36 (ST Micro NAND 64MiB
> 1,8V 8-bit)
> Bad block table found at page 131040, version 0x01
> Bad block table found at page 131008, version 0x01
> imxfb at imxfb0: i.MX Framebuffer driver
> ULPI Vendor ID 0xffffff92    Product ID 0xffffff92
> No ISP1504 found
> ehci at ehci0: USB EHCI 1.00
> cfi_protect: protect 0xc0040000 (size 131072)
> 
> Using environment in NOR Flash
> initialising PLLs: 0xa7f1ea18 0xa7f291f4
> Malloc space: 0xa6f00000 -> 0xa7f00000 (size 16 MB)
> Stack space : 0xa6ef8000 -> 0xa6f00000 (size 32 kB)
> running /env/bin/init...
> 
> Hit any key to stop autoboot:  2
> 
> type update_kernel nand|nor [<imagename>] to update kernel into flash
> type update_root nand|nor [<imagename>] to update rootfs into flash
> 
> barebox:/

-- 
                                                     ~. .~   Tk Open Systems
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