Linux/AM5728: Errata i202 workaround

Gerard

Part Number: AM5728
Other Parts Discussed in Thread: 4460, 4430

Tool/software: Linux

Hello,

Has the workaround for AM5728 errata item i202 (MDR1 Access Can Freeze UART Module) been implemented in one of the Processor SDK releases? If so:

Is it implemented within U-Boot or the Linux kernel?
What version of the Processor SDK was the workaround introduced?

Thanks!

over 7 years ago

0 Steve Kipisz over 7 years ago

TI__Genius 15510 points

I'll take a look at this later today.

Steve K.

0 Steve Kipisz over 7 years ago in reply to Steve Kipisz

TI__Genius 15510 points

I didn't see anything in u-boot, but the errata is implemented in the 8250_omap.c driver. I found this comment before a subroutine.

/*
* Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
* The access to uart register after MDR1 Access
* causes UART to corrupt data.
*
* Need a delay =
* 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
* give 10 times as much
*/

The comment should also include AM57xx.

Steve K.

0 Praneeth Bajjuri over 7 years ago in reply to Steve Kipisz

TI__Expert 6506 points

Additional info:

1) fix is only in linux kernel
original fix >> git.ti.com/.../
which later is moved to 8250_omap >> git.ti.com/.../

2)The fix has been in mainline since 3+ years.
so, fix should have been in ti baseline since Processor SDK Linux 02.00.00
processors.wiki.ti.com/.../Processor_SDK_Linux_Release_Notes

0 Gerard over 7 years ago in reply to Steve Kipisz

Expert 1290 points

Thank you both for your help!

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Linux/AM5728: Errata i202 workaround