Commit 630a8b25 authored Nov 02, 2008 by Atsushi Nemoto Committed by Bartlomiej Zolnierkiewicz Nov 02, 2008

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>

parent ccd32e22

drivers/ide/tx4938ide.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -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]);
		}

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