On Sun, 26 May 2013, Laurent Vivier wrote:
> Please send any patch you want I test (including Kconfig one)
Please try this one (with CONFIG_EARLY_PRINTK=y). I've compile tested but
have no hardware here to run it. This patch should fix a couple of bugs,
though perhaps not the one that is causing the unexpected irq (?)
As I recall the crash is a bit unpredictable, but I could reliably trigger
an unexpected interrupt with a serial cable connected to a terminal
emulator with hardware handshaking by bringing the emultator online when
the kernel first begins to execute.
HTH
Finn
--- a/arch/m68k/kernel/head.S 2013-05-28 21:28:52.000000000 +1000
+++ b/arch/m68k/kernel/head.S 2013-05-28 21:37:33.000000000 +1000
@@ -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)
--
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