CVS commit: src/sys/arch/hpcsh/dev/hd64461

["Rin Okuyama" <rin%netbsd.org@localhost>]

Module Name:    src
Committed By:   rin
Date:           Mon Oct 11 02:30:01 UTC 2021

Modified Files:
        src/sys/arch/hpcsh/dev/hd64461: hd64461pcmcia.c

Log Message:
Fix workaround for SH-3 PCMCIA bug in accordance with description
found in TECH I vol. 14 (CQ Publishing, Tokyo, 2002, in Japanese),
as well as experiment on real hardware:

Byte-access to area 6 becomes word-access (both CE1# and CE2# are
wrongly asserted), if preceding access is word-wise. Inserting a
dummy byte-access works around the problem. Area 5 is not affected.

Therefore,

(1) Insert a dummy byte-read before all byte-wise operations.

(2) Restrict the workaround to area 6 (channel 0), and rename
    fixup_sh3_pcmcia_area() to fixup_sh3_pcmcia_area6() for clarity.

Also, we used to use 0xba000000 (== HD64461_PCC0_IOBASE) as target
for the dummy read. However, this can modify device states, which
breaks ep(4) at least. Thus,

(3) Use HD64461_PCC0_MEMBASE as target for the dummy read. This is
    assigned to attribute memory space, and byte-read should be
    harmless.


To generate a diff of this commit:
cvs rdiff -u -r1.54 -r1.55 src/sys/arch/hpcsh/dev/hd64461/hd64461pcmcia.c

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