linux-kernel - [PATCH] m68k/mac: Fix reboot hang on Mac IIci

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Message-Id: <480ebd1249d229c6dc1f3f1c6d599b8505483fd8.1714797072.git.fthain@linux-m68k.org>
Date: Sat, 04 May 2024 14:31:12 +1000
From: Finn Thain <fthain@...ux-m68k.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Joshua Thompson <funaho@...ai.org>,
    Stan Johnson <userm57@...oo.com>,
    linux-m68k@...ts.linux-m68k.org,
    linux-kernel@...r.kernel.org
Subject: [PATCH] m68k/mac: Fix reboot hang on Mac IIci

Calling mac_reset() on a Mac IIci does reset the system, but what
follows is a POST failure that requires a manual reset to resolve.
Avoid that by using the 68030 asm implementation instead of the C
implementation.

Apparently the SE/30 has a similar problem as it has used the asm
implementation since before git. This patch extends that solution to
other systems with a similar ROM.

After this patch, the only systems still using the C implementation are
68040 systems where adb_type is either MAC_ADB_IOP or MAC_ADB_II. This
implies a 1 MiB Quadra ROM.

This now includes the Quadra 900/950, which previously fell through to
the "should never get here" catch-all.

Reported-and-tested-by: Stan Johnson <userm57@...oo.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@...ux-m68k.org>
---
Tested on Mac IIci & IIfx, Quadra 630 & 650, Daystar Mac II, QEMU.

Some corner cases remain problematic. For example, a stock Mac II or
a Mac IIci with a 68040 accelerator will still use the C routine, because
mac_reset() lacks an asm implementation for '020 and '040 systems.

However, amiga_reset(), atari_reset() and mac_reset() do have a lot in
common, which suggests that a generic asm reset function parameterized by
final JMP location may be a useful refactoring. This would provide the
'020 and '040 handling missing here and could potentially replace
hp300_reset(), dn_dummy_reset() and q40_reset().
---
 arch/m68k/mac/misc.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/arch/m68k/mac/misc.c b/arch/m68k/mac/misc.c
index 4c8f8cbfa05f..e7f0f72c1b36 100644
--- a/arch/m68k/mac/misc.c
+++ b/arch/m68k/mac/misc.c
@@ -453,30 +453,18 @@ void mac_poweroff(void)
 
 void mac_reset(void)
 {
-	if (macintosh_config->adb_type == MAC_ADB_II &&
-	    macintosh_config->ident != MAC_MODEL_SE30) {
-		/* need ROMBASE in booter */
-		/* indeed, plus need to MAP THE ROM !! */
-
-		if (mac_bi_data.rombase == 0)
-			mac_bi_data.rombase = 0x40800000;
-
-		/* works on some */
-		rom_reset = (void *) (mac_bi_data.rombase + 0xa);
-
-		local_irq_disable();
-		rom_reset();
 #ifdef CONFIG_ADB_CUDA
-	} else if (macintosh_config->adb_type == MAC_ADB_EGRET ||
-	           macintosh_config->adb_type == MAC_ADB_CUDA) {
+	if (macintosh_config->adb_type == MAC_ADB_EGRET ||
+	    macintosh_config->adb_type == MAC_ADB_CUDA) {
 		cuda_restart();
+	} else
 #endif
 #ifdef CONFIG_ADB_PMU
-	} else if (macintosh_config->adb_type == MAC_ADB_PB2) {
+	if (macintosh_config->adb_type == MAC_ADB_PB2) {
 		pmu_restart();
+	} else
 #endif
-	} else if (CPU_IS_030) {
-
+	if (CPU_IS_030) {
 		/* 030-specific reset routine.  The idea is general, but the
 		 * specific registers to reset are '030-specific.  Until I
 		 * have a non-030 machine, I can't test anything else.
@@ -524,6 +512,18 @@ void mac_reset(void)
 		    "jmp %/a0@\n\t" /* jump to the reset vector */
 		    ".chip 68k"
 		    : : "r" (offset), "a" (rombase) : "a0");
+	} else {
+		/* need ROMBASE in booter */
+		/* indeed, plus need to MAP THE ROM !! */
+
+		if (mac_bi_data.rombase == 0)
+			mac_bi_data.rombase = 0x40800000;
+
+		/* works on some */
+		rom_reset = (void *)(mac_bi_data.rombase + 0xa);
+
+		local_irq_disable();
+		rom_reset();
 	}
 
 	/* should never get here */
-- 
2.39.3