[#5739] Blackfin serial dma is wonky after 2.6.32 upgrade

Submitted By: Mike Frysinger

Open Date

2009-12-03 19:42:21 Close Date

2010-01-19 01:21:16

Priority:

Medium Assignee:

Sonic Zhang

Status:

Closed Fixed In Release:

N/A

Found In Release:

2010R1 Release:

Category:

N/A Board:

N/A

Processor:

ALL Silicon Revision:

Is this bug repeatable?:

Yes Resolution:

Fixed

Uboot version or rev.:

Toolchain version or rev.:

trunk 3760

App binary format:

N/A

Summary: Blackfin serial dma is wonky after 2.6.32 upgrade

Details:

the serial core under went some changes that seems to have made our dma mode angry. boot up a BF537-STAMP_defconfig and see the misbehavior. RX seems to work fine, but TX lags way behind.

Follow-ups

--- Mike Frysinger 2009-12-15 15:27:24

as a data point, vanilla 2.6.32 and current master (2.6.33-rc0) dont suffer this

problem. but i havent picked through the big pile of serial changes we have

locally to find out which one is causing the problem exactly.

--- Sonic Zhang 2009-12-15 23:07:44

Just figure out the cacheflush against the tx dma buffer should not be punt,

because it is allocated in cacheable memory region by kernel. Only the rx dma

buffer is allocated in uncacheable DMA region in bfin serial driver.

Fixed.

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