U-Boot is broken on real N900 HW

[Pali Rohár]

On Wednesday 01 April 2020 12:32:29 Merlijn Wajer wrote:
> Hi,
> 
> On 01/04/2020 00:42, Pali Rohár wrote:
> > On Wednesday 01 April 2020 00:35:07 Pali Rohár wrote:
> >> This patch series contain fixes for Nokia RX-51 board (aka N900).
> >> After these changes it is possible to run U-Boot in qemu emulator again.
> >> And U-Boot can boot kernel image from RAM, eMMC or OneNAND memory without
> >> problem.
> > 
> > But on real Nokia N900 device is U-Boot crashing in reboot loop.
> > 
> > I do not have serial console for Nokia N900 to debug this issue, but
> > seems that it is related to OMAP I2C and OMAP HS MMC code. Problem is
> > that there is no crash and even no error in qemu emulator so I cannot
> > debug this issue.
> > 
> > First problem is around /* reset lp5523 led */ code in rx51.c. On real
> > N900 device it generates repeating messages:
> > 
> >   Check if pads/pull-ups of bus are properly configured
> >   Timed out in wait_for_event: status=0000
> > 
> > When I commented that few lines all these messages disappeared. So
> > problem is with OMAP I2C.
> > 
> > Second problem happen after misc_init_r() function finishes. U-Boot just
> > prints on N900 screen message "data abort" and reboots. As I do not have
> > serial console it is hard to debug. but I figured out that problem is in
> > mmc_set_ios() function in mmc.c file. In function mmc_set_clock() I put
> > debug info prior to mmc_set_ios() call and after it, and debug info
> > prior was printed, not after.
> > 
> > I remember that somebody had serial jig for Nokia N900, could somebody
> > look at this reboot loop problem?
> > 
> > And any idea how should be OMAP I2C configured in U-Boot to correctly
> > work?
> > 
> > Maybe I will try to find some time to git bisect which change broke
> > U-Boot on real N900 hardware.
> 
> Took latest u-boot master, applied patches and this is the result on
> serial (first part is NOLO booting, I think that can be ignored) [1].

...

> U-Boot 2020.04-rc4-00033-g7dbafe0634-dirty (Apr 01 2020 - 12:15:47 +0200)
> 
> OMAP3530-HS ES3.1, CPU-OPP2, L3-165MHz, Max CPU Clock 600 MHz
> Nokia RX-51 + LPDDR/OneNAND
> I2C:   ready
> DRAM:  256 MiB
> NAND:  0 Bytes

Looks like that something with NAND is broken.

> MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
> In:    vga
> Out:   vga
> Err:   vga
> Timed out in wait_for_event: status=0100
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> Timed out in wait_for_event: status=0000
> Check if pads/pull-ups of bus are properly configured
> i2c_read (addr phase): pads on bus probably not configured (status=0x10)
> i2c_write: timed out writig last byte!

These i2c errors are caused by

	/* reset lp5523 led */
	i2c_set_bus_num(1);
	state = 0xff;
	i2c_write(0x32, 0x3d, 1, &state, 1);
	i2c_set_bus_num(0);

Is there anything which needs to be done to initialize i2c bus 1?
Because this code is working fine on older U-Boot version.

Was something changed to OMAP i2c bus code in U-Boot?

> OMAP die ID: 031400240000000004036ac10b01100f
> OMAP3530-HS ES3.1, CPU-OPP2, L3-165MHz, Max CPU Clock 600 MHz
> 

And then U-Boot freeze, right?

Any idea how to debug this issue?

On my N900 I'm getting "data abort" error on display and then instant
reboot.