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| author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2008-11-02 23:40:09 +0300 |
|---|---|---|
| committer | Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> | 2008-11-02 23:40:09 +0300 |
| commit | 630a8b2500c8d04e87e597c4afa5e1fafff04591 (patch) | |
| tree | 846c569c1f4f16bf6c1fdef1071850ce48f2c920 /drivers | |
| parent | ccd32e221c3e3797ac56305c554ad8b07c13c815 (diff) | |
| download | linux-630a8b2500c8d04e87e597c4afa5e1fafff04591.tar.xz | |
tx4938ide: Check minimum cycle time and SHWT range (v2)
SHWT value is used as address valid to -CSx assertion and -CSx to -DIOx
assertion setup time, and contrarywise, -DIOx to -CSx release and -CSx
release to address invalid hold time, so it actualy applies 4 times and
so constitutes -DIOx recovery time. Check requirement of the recovery
time and cycle time. Also check SHWT maximum value.
Suggested-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: ralf@linux-mips.org
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/ide/tx4938ide.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/ide/tx4938ide.c b/drivers/ide/tx4938ide.c index fa660f931a11..9c518e722707 100644 --- a/drivers/ide/tx4938ide.c +++ b/drivers/ide/tx4938ide.c @@ -39,10 +39,17 @@ static void tx4938ide_tune_ebusc(unsigned int ebus_ch, /* Address-valid to DIOR/DIOW setup */ shwt = DIV_ROUND_UP(t->setup, cycle); + /* -DIOx recovery time (SHWT * 4) and cycle time requirement */ + while ((shwt * 4 + wt + (wt ? 2 : 3)) * cycle < t->cycle) + shwt++; + if (shwt > 7) { + pr_warning("tx4938ide: SHWT violation (%d)\n", shwt); + shwt = 7; + } pr_debug("tx4938ide: ebus %d, bus cycle %dns, WT %d, SHWT %d\n", ebus_ch, cycle, wt, shwt); - __raw_writeq((cr & ~(0x3f007ull)) | (wt << 12) | shwt, + __raw_writeq((cr & ~0x3f007ull) | (wt << 12) | shwt, &tx4938_ebuscptr->cr[ebus_ch]); } |