CVS commit: src/sys/arch/alpha/pci

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Sun Jul 18 19:58:34 UTC 2021

Modified Files:
        src/sys/arch/alpha/pci: tsp_dma.c

Log Message:
According to section 8.1.2.2 of the Tsunami/Typhoon hardware reference
manual (DS-0025A-TE), the SGMAP TLB is arranged as 168 locations of 4
consecutive quadwords.  It seems that on some revisions of the Pchip,
SGMAP translation is not perfectly reliable unless we align the DMA
segments to the TLBs natural boundaries (observed on the API CS20).

N.B. the Titan (as observed on a Compaq DS25) does not seem to have this
problem, but we'll play it safe and run this way on both variants.

PR port-alpha/40604.


To generate a diff of this commit:
cvs rdiff -u -r1.20 -r1.21 src/sys/arch/alpha/pci/tsp_dma.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.