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Commit 630a8b25 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Bartlomiej Zolnierkiewicz
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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: default avatarSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: ralf@linux-mips.org
Acked-by: default avatarSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: default avatarBartlomiej 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]);

}