U-Boot is broken on real N900 HW

[Pali Rohár]

On Thursday 02 April 2020 20:42:31 Pali Rohár wrote:
> 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.

Above code worked fine for U-Boot 2013.04, but in git version from
January 2015 it prints above error messages.

On on internet forums I see these error messages also from other OMAP3
board, e.g. beagle board.

Has somebody some working OMAP3 board? And can test if it works with
recent version of U-Boot? I guess that above i2c problem would happen
also on other OMAP3 boards.

> 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.

It looks like that omap hs mmc code cause that freeze/reboot on real HW.
Was there some significat change to OMAP3 or omap hs mmc?