RE: [PATCH V1] serial: imx: revert setup DCEDTE early and ensure DCD and RI irqs to be off

[Steve Twiss <stwiss.opensource@diasemi.com>]

Hi Fabio,

On 24 May 2017 12:53 Fabio Estevam wrote:
> Subject: Re: [PATCH V1] serial: imx: revert setup DCEDTE early and ensure DCD and RI irqs to be off
> On Wed, May 24, 2017 at 7:32 AM, Steve Twiss wrote:
> 
> > The USB to UART connection gets corrupted.
> > If this patch is applied to the kernel, the i.MX6 Q (quad), and only this board as far as
> > we know, starts to fail. This does *not* change the i.MX6DL and other sabre boards
> > have been tested on kernelci.org and do not see a problem.
> >
> > An NXP/Freescale SABRESD i.MX6 Q board is requred.
> >
> > My system for testing is to TFTP the Linux kernel over an ethernet connection. The
> > U-boot executes okay and the UART is working at that point. When the kernel loads
> > the console trace becomes garbled, in the sense that I get the some characters being
> > output to the console, in the style of the kernel starting up, but they are not correct.
> >
> > I expect the kernel has started ok, but I am unable to read/write through the UART
> > console because of corruptions.
> >
> > Console log with the output I am seeing with linux-next/v4.12-rc2
> > --- 8< ---
> > U-Boot 2009.08-00001-gf65536a (Jan 12 2015 - 15:47:19)
> 
> Thanks for your detailed explanation.
> 
> I also have a mx6q sabresd board here, but the error did not happen
> when I use a recent U-Boot version.
>
> I would like to use the same U-Boot version here as well to help
> debugging this problem.

For the previous tests I was using a slightly modified U-Boot from an old Freescale
Android release JB43_110, but I've just compiled up the standard u-boot from
the Freescale git repository, and I get the same results.

> Could you please let me know which 2009.08 branch you used? Is it any
> one from git.freescale.com
> http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/refs/heads ?

I used this tag: jb4.3_1.1.1-ga
http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/commit/?id=jb4.3_1.1.1-ga

This repo is slightly modified for a project I am working on, but it only queries
the  I2C for devices before printing out some messages, so minor changes I
think. Here's the output from the console:

--- 8< ---
U-Boot 2009.08 (May 24 2017 - 13:15:47)

CPU: Freescale i.MX6 family TO1.2 at 792 MHz
Thermal sensor with ratio = 200
Temperature:   38 C, calibration data 0x5f15527d
mx6q pll1: 792MHz
mx6q pll2: 528MHz
mx6q pll3: 480MHz
mx6q pll8: 50MHz
ipg clock     : 66000000Hz
ipg per clock : 66000000Hz
uart clock    : 80000000Hz
cspi clock    : 60000000Hz
ahb clock     : 132000000Hz
axi clock   : 264000000Hz
emi_slow clock: 132000000Hz
ddr clock     : 528000000Hz
usdhc1 clock  : 198000000Hz
usdhc2 clock  : 198000000Hz
usdhc3 clock  : 198000000Hz
usdhc4 clock  : 198000000Hz
nfc clock     : 24000000Hz
Board: i.MX6Q-SABRESD: unknown-board Board: 0x63012 [POR ]
Boot Device: SD
I2C:   ready
DRAM:   1 GB
MMC:   FSL_USDHC: 0,FSL_USDHC: 1,FSL_USDHC: 2,FSL_USDHC: 3
In:    serial
Out:   serial
Err:   serial
Found PFUZE100! deviceid=10,revid=11
Net:   got MAC address from IIM: 00:04:9f:02:e3:0a
FEC0 [PRIME]
Hit any key to stop autoboot:  0
PHY indentify @ 0x1 = 0x004dd074
FEC: Link is Up 796d
Using FEC0 device
TFTP from server 192.168.2.1; our IP address is 192.168.2.2
Filename 'uImage_dtb.imx6q.v4.12-rc2'.
Load address: 0x12000000
Loading: #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         #################################################################
         ##########################################################
done
Bytes transferred = 5951076 (5ace64 hex)
## Booting kernel from Legacy Image at 12000000 ...
   Image Name:
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    5951012 Bytes =  5.7 MB
   Load Address: 10800000
   Entry Point:  10800000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK
OK
--- 8< ---

Regards,
Stephen