From 630a8b2500c8d04e87e597c4afa5e1fafff04591 Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Sun, 2 Nov 2008 21:40:09 +0100 Subject: [PATCH] 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 Signed-off-by: Atsushi Nemoto Cc: ralf@linux-mips.org Acked-by: Sergei Shtylyov Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/tx4938ide.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) 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]); } -- 2.20.1