[U-Boot] [PATCH 2/2] watchdog: omap_wdt: Disable DM watchdog support in SPL

[Suniel Mahesh]

On 17/07/19 22:58, Tom Rini wrote:
> On Fri, Jul 12, 2019 at 02:53:47PM +0530, sunil.m at techveda.org wrote:
> 
>> From: Suniel Mahesh <suniel.spartan at gmail.com>
>>
>> This patch disables DM watchdog support for SPL builds and uses
>> the legacy omap watchdog on TI AM335x chipsets.
>>
>> The following build error is reported if DM watchdog support was enabled in SPL:
>>
>>   CC      spl/drivers/usb/gadget/rndis.o
>>   LD      spl/drivers/usb/gadget/built-in.o
>>   LD      spl/drivers/usb/musb-new/built-in.o
>>   LD      spl/drivers/built-in.o
>>   LD      spl/u-boot-spl
>> arm-linux-ld.bfd: u-boot-spl section .u_boot_list will not fit in region .sram
>> arm-linux-ld.bfd: region .sram overflowed by 440 bytes
>> make[1]: *** [spl/u-boot-spl] Error 1
>> make: *** [spl/u-boot-spl] Error 2
>>
>> Tested on BeagleboneBlack board.
>>
>> Signed-off-by: Suniel Mahesh <sunil.m at techveda.org>
> 
> My concern here is that if we don't configure the watchdog we could now
> end up in the case where the WDT trips while we're doing a slow boot
> such as UART.  

Here in SPL, watchdog is configured but it doesn't use DT and DM. It uses
legacy driver(non DT/non DM). I have also tested a slow boot(UART) as you indicated on 
AM335X based BeagleboneBlack board. Here are the results:

1. SPL trying to load u-boot via UART, if it can't find it, then we need to reset the board:

U-Boot SPL 2019.07-00058-g076875b-dirty (Jul 18 2019 - 10:39:43 +0530)
Trying to boot from UART
CCCCCCCCCCspl: ymodem err - Timed out
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

2. if we provide u-boot-dtb.bin, then it loads without any problem.

Hope I gave some inputs here.

As was mentioned elsewhere we might need to switch to
> using platdata so this still fits? 

right now watchdog driver in SPL is not using platdata, its just a plain
driver. Do we need to convert the driver in SPL to use platdata ? 

And we will need the whole of
> "omap2" to build after this is applied, thanks.
> 
yes this needs to be done, once all these are fixed and more over these patches
are dependant on Marek Vasuts's patches.
https://patchwork.ozlabs.org/patch/1112591/

Regards
Sunil