[src/trunk]: src/sys/dev/ic during SRST (softreset), make a short delay betwe...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/88ca1654b7c3
branches:  trunk
changeset: 446002:88ca1654b7c3
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Mon Nov 19 22:05:22 2018 +0000

description:
during SRST (softreset), make a short delay between the RST set and
clear; SATA specifies minimum 5 usec for the toggle period, and
some controllers (seems usually on AMD motherboards) actually require it

this fixes the 'clearing WDCTL_RST failed' error in PR kern/53307
and PR kern/53524

confirmed working on a ASUS Prime A320M-K mainboard by me, and by Patrick
Welche on another Ryzen system

XXX pullup-8

diffstat:

 sys/dev/ic/ahcisata_core.c |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (32 lines):

diff -r 6849c5e3eb96 -r 88ca1654b7c3 sys/dev/ic/ahcisata_core.c
--- a/sys/dev/ic/ahcisata_core.c        Mon Nov 19 21:52:24 2018 +0000
+++ b/sys/dev/ic/ahcisata_core.c        Mon Nov 19 22:05:22 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ahcisata_core.c,v 1.68 2018/11/19 21:52:24 jdolecek Exp $      */
+/*     $NetBSD: ahcisata_core.c,v 1.69 2018/11/19 22:05:22 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ahcisata_core.c,v 1.68 2018/11/19 21:52:24 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ahcisata_core.c,v 1.69 2018/11/19 22:05:22 jdolecek Exp $");
 
 #include <sys/types.h>
 #include <sys/malloc.h>
@@ -841,6 +841,13 @@
                break;
        }
 
+       /*
+        * SATA specification has toggle period for SRST bit of 5 usec. Some
+        * controllers fail to process the SRST clear operation unless
+        * we wait for at least this period between the set and clear commands.
+        */
+       ata_delay(chp, 10, "ahcirstw", flags);
+
        cmd_h->cmdh_flags = htole16(RHD_FISLEN / 4 |
            (drive << AHCI_CMDH_F_PMP_SHIFT));
        cmd_h->cmdh_prdbc = 0;