From 447808bf500a7cc92173266a59f8a494e132b122 Mon Sep 17 00:00:00 2001
From: Stewart Smith <stewart@linux.ibm.com>
Date: Thu, 29 Mar 2018 17:02:46 +1100
Subject: [PATCH] hvc_opal: don't set tb_ticks_per_usec in udbg_init_opal_common()
Git-commit: 447808bf500a7cc92173266a59f8a494e132b122
Patch-mainline: v4.18-rc1
References: bsc#1051510

time_init() will set up tb_ticks_per_usec based on reality.
time_init() is called *after* udbg_init_opal_common() during boot.

from arch/powerpc/kernel/time.c:
  unsigned long tb_ticks_per_usec = 100; /* sane default */

Currently, all powernv systems have a timebase frequency of 512mhz
(512000000/1000000 == 0x200) - although there's nothing written
down anywhere that I can find saying that we couldn't make that
different based on the requirements in the ISA.

So, we've been (accidentally) thwacking the (currently) correct
(for powernv at least) value for tb_ticks_per_usec earlier than
we otherwise would have.

The "sane default" seems to be adequate for our purposes between
udbg_init_opal_common() and time_init() being called, and if it isn't,
then we should probably be setting it somewhere that isn't hvc_opal.c!

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/tty/hvc/hvc_opal.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c
index 2ed07ca6389e..9645c0062a90 100644
--- a/drivers/tty/hvc/hvc_opal.c
+++ b/drivers/tty/hvc/hvc_opal.c
@@ -318,7 +318,6 @@ static void udbg_init_opal_common(void)
 	udbg_putc = udbg_opal_putc;
 	udbg_getc = udbg_opal_getc;
 	udbg_getc_poll = udbg_opal_getc_poll;
-	tb_ticks_per_usec = 0x200; /* Make udelay not suck */
 }
 
 void __init hvc_opal_init_early(void)
-- 
2.16.4