how to integrate iomux C code in u-boot and linux?

[jbd64]

Hi,

I'm working on a project with imx6Solo custom board. My colleague generates output C code from iomux-tool v3, and now I have to integrate this on u-boot and linux kernel. I've read i.MX_6Solo6DualLite_BSP_Porting_Guide but it doesn't explain integration process of code provided by iomux.

Can you explain me how to integrate iomux C code in u-boot and linux ?

Thanks !

[weidong_sun]

Hello,jbd64,

(1)In u-boot:

     you can open u-boot/board/freescale/mx6sl_arm2/mx6sl_arm.c and refer to the iomux usage of those pins.(such as i2c,spi,eMMC pins etc)

(2)In linux kernel:

     you can open linux/arch/arm/mach-mx6/board-mx6sl_common.h and find structure :

static iomux_v3_cfg_t mx6sl_brd_pads[] = {

....

/* all signals used on board are iomuxed here, you can add signal you want here */

....

}

(3)IOMUX definitions for i.mx6SL

open linux/arch/arm/plat-mxc/include/mach/iomux-mx6sl.h, you will find all signals are defined for i.mx6SL. if you use one, you only need to add it to (2)

Regards,

Weidong

[YixingKong]

Weidong, could you finish the customr's questions?

Thanks,

Yixing

[leoschwab]

Bumping this thread.  We will shortly be facing the same issue for an i.MX6DL design.  Our HW designer has set up all the IOMux settings; we simply need a way to translate them to a form compatible with the existing 3.0.35 kernel sources.

[jbd64]

So, I have to begin with imx6Solo_arm2 board and customize it for my custom board ?

I've read that imx6Solo processor is compatible with imx6DualLite but not with imx6SoloLight.

Besides, output generated by iomux tools is like this :

     output

     |__ board

          |__ mx6sdl

               |__ iomux_config.h

               |__ rev__iomux

                    |__ dcic_iomux_config.c

                    |__ ecspi_iomux_config.c

                    |__ eim_iomux_config.c

                    ...

                    |__ usdhc_iomux_config.c

                    |__ wdog_iomux_config.c

     |__ sdk

          |__ include

               |__ mx6sdl

                    |__ registers

                         |__ regs.h

                         |__ regsiomuxc.h

- In output/board/mx6sdl/rev__iomux/*_iomux_config.c files, there is MUX control registers pad's functions definition, and pad characteristics.

- In output/sdk/include/mx6sdl/registers/regsiomuxc.h file, definition of all the PADs (i guess).

- In attachment, a tarball file containing output directory, with all sub-directories and files.

Can you explain me how to integrate these IOMUX code provided by IOMUX TOOLS in u-boot and linux ?

I've already looked at u-boot mx6sl_arm.c file, and linux kernel files.

What I think is that IOMUX TOOLS generates all the PADs definitions in regsiomuxc.h file.

Problem is u-boot and linux already have a file which defines all the PADS : for u-boot : include/asm-arm/arch-mx6/mx6_pins.h ; for linux : arch/arm/plat-mxc/include/mach/iomux-mx6X.h (X denotes SOC type).

So, how can I mix IOMUXTOOLS code with U-boot and Linux code ?

[leoschwab]

For what it's worth, I wrote a program to translate the IOMux output into the form used by the Yocto/FSL U-Boot and the 3.0.35 Linux kernel.  The translation is ugly and, in some places, incomplete.  But at least I have something to feed U-Boot now...

EDIT:  *sigh* Never mind.  Linux re-packs the pad control bits so that the whole thing will fit in a uint64_t.

Also:  Neither U-Boot's nor Linux's IOMUX_PAD() macros provide for writing to the Pad Group Control registers.

Also also:  Although the macros are used identically, the IOMUX_PAD() field definitions are different between U-Boot and Linux (Linux sets aside 18 bits; U-Boot uses 19).

Happily, I didn't fry any hardware finding this out.  I have more work to do...