[U-Boot] i.MX35PDK: Starting U-Boot from serial NOR-Flash

From: Fabio Estevam <festevam@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] i.MX35PDK: Starting U-Boot from serial NOR-Flash
Date: Thu, 5 Jul 2012 15:06:27 -0300	[thread overview]
Message-ID: <CAOMZO5BtJ_SYbbWXL+jEgEsQJBKCA9AjNyAa+mrhfswLqfT1Tg@mail.gmail.com> (raw)
In-Reply-To: <334319B2EBE0B144BAE1402B79D82DC5D31358D8@srvpegasus>

Hi Michael,

On Thu, Jul 5, 2012 at 6:09 AM, Hornung, Michael <mhornung@init-ka.de> wrote:
> Hi Fabio,
>
> thank you very much for your reply.
>
>> With these values you can create a correct imximage.cfg file for mx35pdk.
>
> Thank you, I'll try my best.
>
>>> $ ./tools/mkimage -n ./board/freescale/mx35pdk/imximage.cfg -T imximage -e 0xA0000000 -d u-boot.bin u-boot.imx

The best way to generate 'u-boot.imx' is to simply do 'make
u-boot.imx' and then you don't need to pass the above line manually.

> Can you tell me which address I have to append to the -e switch of the mkimage program? I think that my choice (0xA0000000) is
> incorrect since it is /CS0 memory region of the WEIM. Is it 0x10000000 for internal RAM? And if so, do I have to change the following
> define within "include/configs/mx35pdk.h", too?
>
> /* Set TEXT at the beginning of the NOR flash */
> #define CONFIG_SYS_TEXT_BASE    0xA0000000

In internal mode you should do:

#define CONFIG_LOADADDR		0x80800000
#define CONFIG_SYS_TEXT_BASE    0x87800000

for mx35.

You probably will need to skip the RAM init in
board/freescale/mx35pdk/lowlevel_init.S

For a quick test I would remove the call to 'setup_sdram' there,
because RAM will be inited by the values from your created
imximage.cfg file.

After you managed to boot from internal mode, then we can think on how
to properly handle both internal and external boot modes. Maybe we
will need to create another mx35pdk target so that we can handle the
internal mode.

>> So my suggestion for you is to try to boot from internal boot mode first. Try booting from SD card first as this would be easier.
>
> Could you please give a short explanation, why it is easier to boot from SD than from serial NOR?

Well, I don't have SPI NOR populated on my board ;-)

Besides that, flashing an SD card is much simpler. Please read
doc/README.imximage

Booting from SD is the mode we support by default on other
mx25/mx51/mx53/mx6 boards.

Regards,

Fabio Estevam