Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k

Pull m68k fix from Geert Uytterhoeven:
 "A boot lock-up on Mac, also destined for stable"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k/mac: Fix unexpected interrupt with CONFIG_EARLY_PRINTK

1 files changed, 19 insertions, 10 deletions

diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S
index d197e7ff62c5..ac85f16534af 100644
--- a/arch/m68k/kernel/head.S
+++ b/arch/m68k/kernel/head.S
@@ -2752,11 +2752,9 @@ func_return	get_new_page
 #ifdef CONFIG_MAC
 
 L(scc_initable_mac):
-	.byte	9,12		/* Reset */
 	.byte	4,0x44		/* x16, 1 stopbit, no parity */
 	.byte	3,0xc0		/* receiver: 8 bpc */
 	.byte	5,0xe2		/* transmitter: 8 bpc, assert dtr/rts */
-	.byte	9,0		/* no interrupts */
 	.byte	10,0		/* NRZ */
 	.byte	11,0x50		/* use baud rate generator */
 	.byte	12,1,13,0	/* 38400 baud */
@@ -2899,6 +2897,7 @@ func_start	serial_init,%d0/%d1/%a0/%a1
 	is_not_mac(L(serial_init_not_mac))
 
 #ifdef SERIAL_DEBUG
+
 /* You may define either or both of these. */
 #define MAC_USE_SCC_A /* Modem port */
 #define MAC_USE_SCC_B /* Printer port */
@@ -2908,9 +2907,21 @@ func_start	serial_init,%d0/%d1/%a0/%a1
 #define mac_scc_cha_b_data_offset	0x4
 #define mac_scc_cha_a_data_offset	0x6
 
+#if defined(MAC_USE_SCC_A) || defined(MAC_USE_SCC_B)
+	movel	%pc@(L(mac_sccbase)),%a0
+	/* Reset SCC device */
+	moveb	#9,%a0@(mac_scc_cha_a_ctrl_offset)
+	moveb	#0xc0,%a0@(mac_scc_cha_a_ctrl_offset)
+	/* Wait for 5 PCLK cycles, which is about 68 CPU cycles */
+	/* 5 / 3.6864 MHz = approx. 1.36 us = 68 / 50 MHz */
+	movel	#35,%d0
+5:
+	subq	#1,%d0
+	jne	5b
+#endif
+
 #ifdef MAC_USE_SCC_A
 	/* Initialize channel A */
-	movel	%pc@(L(mac_sccbase)),%a0
 	lea	%pc@(L(scc_initable_mac)),%a1
 5:	moveb	%a1@+,%d0
 	jmi	6f
@@ -2922,9 +2933,6 @@ func_start	serial_init,%d0/%d1/%a0/%a1
 
 #ifdef MAC_USE_SCC_B
 	/* Initialize channel B */
-#ifndef MAC_USE_SCC_A	/* Load mac_sccbase only if needed */
-	movel	%pc@(L(mac_sccbase)),%a0
-#endif	/* MAC_USE_SCC_A */
 	lea	%pc@(L(scc_initable_mac)),%a1
 7:	moveb	%a1@+,%d0
 	jmi	8f
@@ -2933,6 +2941,7 @@ func_start	serial_init,%d0/%d1/%a0/%a1
 	jra	7b
 8:
 #endif	/* MAC_USE_SCC_B */
+
 #endif	/* SERIAL_DEBUG */
 
 	jra	L(serial_init_done)
@@ -3006,17 +3015,17 @@ func_start	serial_putc,%d0/%d1/%a0/%a1
 
 #ifdef SERIAL_DEBUG
 
-#ifdef MAC_USE_SCC_A
+#if defined(MAC_USE_SCC_A) || defined(MAC_USE_SCC_B)
 	movel	%pc@(L(mac_sccbase)),%a1
+#endif
+
+#ifdef MAC_USE_SCC_A
 3:	btst	#2,%a1@(mac_scc_cha_a_ctrl_offset)
 	jeq	3b
 	moveb	%d0,%a1@(mac_scc_cha_a_data_offset)
 #endif	/* MAC_USE_SCC_A */
 
 #ifdef MAC_USE_SCC_B
-#ifndef MAC_USE_SCC_A	/* Load mac_sccbase only if needed */
-	movel	%pc@(L(mac_sccbase)),%a1
-#endif	/* MAC_USE_SCC_A */
 4:	btst	#2,%a1@(mac_scc_cha_b_ctrl_offset)
 	jeq	4b
 	moveb	%d0,%a1@(mac_scc_cha_b_data_offset)