U-Boot i2c bus num 1 is broken on Nokia N900
Pali Rohár
pali at kernel.org
Mon Oct 26 22:48:58 CET 2020
On Monday 27 April 2020 09:03:13 Heiko Schocher wrote:
> Hello Pali,
>
> Am 26.04.2020 um 01:54 schrieb Pali Rohár:
> > Adding Hannes and Heiko to the loop, please look at this problem.
> >
> > On Saturday 25 April 2020 14:11:32 Pali Rohár wrote:
> > > On Saturday 25 April 2020 07:00:58 Adam Ford wrote:
> > > > On Sat, Apr 25, 2020 at 6:50 AM Pali Rohár <pali at kernel.org> wrote:
> > > > >
> > > > > On Saturday 25 April 2020 06:36:58 Adam Ford wrote:
> > > > > > On Sat, Apr 25, 2020 at 5:42 AM Pali Rohár <pali at kernel.org> wrote:
> > > > > > >
> > > > > > > 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.
> > ...
> > > > > > > > > > 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.
>
> The board code in U-Boot is in a very old state... :-(
>
> > > > > > > >
> > > > > > > > > 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);
>
> deprecated ... the board code needs cleanup ...
I converted code to CONFIG_DM_I2C and nothing was changed, issue is
still there...
> > > > > > > > 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.
> > > > > >
> > > > > > There was a conversion a while ago to dm_i2c, and I converted my board
> > > > > > to support using the device tree during the SPL phase, and whenever I
> > > > > > am aware any driver has driver model (DM) support, I try to convert my
> > > > > > board.
> > > > > >
> > > > > > I have a DM3730 and the last check I did was 2020.04-rc1, and it was working
> > > > >
> > > > > Ok, so it either OMAP3430 specific problem or N900 board specific
> > > > > problem. N900 does not use driver model.
> > > >
> > > > i have an OMAP3530 which is basically a 3430, and it works too. I am
> > > > guessing the issue is unique to the N900 or the fact that it's
> > > > high-security. Neither of my boards are HS parts. They are both GP.
> > >
> > > N900 is HS device, but I guess that should be caused by GP vs HS
> > > difference. Working i2c bus 0 and non-working i2c bus 1 could not be
> > > caused by GP vs HS difference. Also I guess that omap hs mmc would be
> > > same on GP and HS boards.
> > ...
> > > > > Before calling i2c_write(0x32, ...) I tried to call i2c_probe(0x32) and
> > > > > it returned error.
> > > > >
> > > > > If I tried to call "i2c dev 1" in U-Boot console, I got tons of errors
> > > > > and basically U-Boot stopped responding.
> > > > >
> > > > > So by above observation it looks like I2C bus num 1 does not work, but
> > > > > I2C bus num 0 works fine.
> > > > >
> > > > > Do I need to call i2c_probe(...) before calling i2c_write(...)?
> > > > >
> > > > > And is something special needed for initializing omap i2c bus num 1?
> > > > > Because from my above observation it looks like that something is
> > > > > missing for bus 1 which in older u-boot version was not needed.
> >
> > Now I was able to find commit which is causing above i2c problems:
> > "Check if pads/pull-ups of bus are properly configured"
> >
> > It is d5243359e1afc957acd373dbbde1cf6c70ee5485:
> >
> > OMAP24xx I2C: Add support for set-speed
> > Adds support for set-speed on the OMAP24xx I2C Adapter.
> > Changes to omap24_i2c_write(...) for polling ARDY Bit from IRQ-Status.
> > Otherwise on a subsequent call the transfer of last byte from the
> > predecessor is aborted and therefore lost. For exmaple when
> > i2c_write(...) is followed by a i2c_setspeed(...) (which has to
> > deactivate and activate master for changing psc,...).
> > Minor cosmetical changes.
> > Signed-off-by: Hannes Petermaier <oe5hpm at oevsv.at>
> > Cc: Heiko Schocher <hs at denx.de>
> >
> > U-Boot version prior this command does not report those i2c errors.
> >
> > Hannes, any idea how your patch could broke omap i2c i2c bus num 1 on
> > Nokia N900?
>
> Hard to say here anything useful, as I do not have the hardware...
>
> The above commit changes:
>
> - udelay(I2C_WAIT);
> + udelay(adap->waitdelay);
>
> May you can check, if adap->waitdelay is the same as I2C_WAIT ?
Yes, it is the same value.
Anyway, I have deeply looked at that commit again and it just adds
support for omap24_i2c_setspeed and into omap24_i2c_write adds following
change:
@@ -464,6 +502,15 @@ static int omap24_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
goto wr_exit;
}
}
+ /*
+ * poll ARDY bit for making sure that last byte really has been
+ * transferred on the bus.
+ */
+ do {
+ status = wait_for_event(adap);
+ } while (!(status & I2C_STAT_ARDY) && timeout--);
+ if (timeout <= 0)
+ printf("i2c_write: timed out writig last byte!\n");
wr_exit:
flush_fifo(adap);
And this change is causing that non-functional i2c bus.
I applied revert of above change on top of the master u-boot branch and
i2c bus num 1 (second) started working on N900 hw:
diff --git a/drivers/i2c/omap24xx_i2c.c b/drivers/i2c/omap24xx_i2c.c
index 0af4e333c4..a49cf89712 100644
--- a/drivers/i2c/omap24xx_i2c.c
+++ b/drivers/i2c/omap24xx_i2c.c
@@ -820,16 +820,6 @@ static int __omap24_i2c_write(void __iomem *i2c_base, int ip_rev, int waitdelay,
}
}
- /*
- * poll ARDY bit for making sure that last byte really has been
- * transferred on the bus.
- */
- do {
- status = wait_for_event(i2c_base, ip_rev, waitdelay);
- } while (!(status & I2C_STAT_ARDY) && timeout--);
- if (timeout <= 0)
- printf("i2c_write: timed out writig last byte!\n");
-
wr_exit:
flush_fifo(i2c_base, ip_rev);
omap_i2c_write_reg(i2c_base, ip_rev, 0xFFFF, OMAP_I2C_STAT_REG);
I have looked into i2c-omap.c linux kernel driver and its transfer
function does not have any such code for waiting ARDY bit.
Why it is there? I have not able to find any information and that
comment is strange... it looks like it was incomplete/broken? workaround
about other issue.
As you can see in log, at the first call status flags contains value
0x0100 and on all other calls it contains just 0x000 status flags.
Therefore ARDY bit is never set, but i2c transfer works fine.
> bye,
> Heiko
> --
> DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-52 Fax: +49-8142-66989-80 Email: hs at denx.de
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