From: Finn Thain <fthain@telegraphics•com.au>
To: Geert Uytterhoeven <geert@linux-m68k•org>
Cc: linux-m68k@vger•kernel.org, linuxppc-dev@lists•ozlabs.org
Subject: [PATCH 01/16] pmac_zilog: fix unexpected irq
Date: Mon, 24 Oct 2011 01:11:09 +1100 [thread overview]
Message-ID: <20111023141115.208699274@telegraphics.com.au> (raw)
In-Reply-To: 20111023141108.856998818@telegraphics.com.au
On most 68k Macs the SCC IRQ is an autovector interrupt and cannot be masked. This can be a problem when pmac_zilog starts up.
For example, the serial debugging code in arch/m68k/kernel/head.S may be used beforehand. It disables the SCC interrupts at the chip but doesn't ack them. Then when a pmac_zilog port is opened and SCC chip interrupts become enabled, the machine locks up with "unexpected interrupt" because request_irq() hasn't happened yet.
Fix this by setting the SCC master interrupt enable bit only after the handler is installed. This is achieved by extracting that operation out of __pmz_startup() and placing it into a seperate routine.
A similar problem arises when the irq is freed. Fix this by resetting the chip first (on m68k mac).
Signed-off-by: Finn Thain <fthain@telegraphics•com.au>
---
This patch has been tested on a variety of m68k Macs but no PowerMacs.
Index: linux-m68k/drivers/tty/serial/pmac_zilog.c
===================================================================
--- linux-m68k.orig/drivers/tty/serial/pmac_zilog.c 2011-10-22 23:02:22.000000000 +1100
+++ linux-m68k/drivers/tty/serial/pmac_zilog.c 2011-10-22 23:02:38.000000000 +1100
@@ -910,8 +910,8 @@ static int __pmz_startup(struct uart_pma
/* Clear handshaking, enable BREAK interrupts */
uap->curregs[R15] = BRKIE;
- /* Master interrupt enable */
- uap->curregs[R9] |= NV | MIE;
+ /* No vector */
+ uap->curregs[R9] |= NV;
pmz_load_zsregs(uap, uap->curregs);
@@ -925,6 +925,17 @@ static int __pmz_startup(struct uart_pma
return pwr_delay;
}
+static void pmz_master_int_control(struct uart_pmac_port *uap, int enable)
+{
+ if (enable) {
+ uap->curregs[R9] |= MIE; /* Master interrupt enable */
+ write_zsreg(uap, R9, uap->curregs[R9]);
+ } else {
+ uap->curregs[R9] &= ~MIE;
+ write_zsreg(uap, 9, FHWRES);
+ }
+}
+
static void pmz_irda_reset(struct uart_pmac_port *uap)
{
uap->curregs[R5] |= DTR;
@@ -976,6 +987,19 @@ static int pmz_startup(struct uart_port
return -ENXIO;
}
+ /*
+ * Most 68k Mac models cannot mask the SCC IRQ so they must enable
+ * interrupts after the handler is installed and not before.
+ */
+#ifndef CONFIG_MAC
+ if (!ZS_IS_CONS(uap))
+#endif
+ {
+ spin_lock_irqsave(&port->lock, flags);
+ pmz_master_int_control(uap, 1);
+ spin_unlock_irqrestore(&port->lock, flags);
+ }
+
mutex_unlock(&pmz_irq_mutex);
/* Right now, we deal with delay by blocking here, I'll be
@@ -1015,6 +1039,11 @@ static void pmz_shutdown(struct uart_por
mutex_lock(&pmz_irq_mutex);
+#ifdef CONFIG_MAC
+ if (!ZS_IS_OPEN(uap->mate))
+ pmz_master_int_control(uap, 0);
+#endif
+
/* Release interrupt handler */
free_irq(uap->port.irq, uap);
@@ -1734,6 +1763,7 @@ static int pmz_resume(struct macio_dev *
goto bail;
}
pwr_delay = __pmz_startup(uap);
+ pmz_master_int_control(uap, 1);
/* Take care of config that may have changed while asleep */
__pmz_set_termios(&uap->port, &uap->termios_cache, NULL);
@@ -2178,6 +2208,9 @@ static int __init pmz_console_setup(stru
* Enable the hardware
*/
pwr_delay = __pmz_startup(uap);
+#ifndef CONFIG_MAC
+ pmz_master_int_control(uap, 1);
+#endif
if (pwr_delay)
mdelay(pwr_delay);
next parent reply other threads:[~2011-10-23 14:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111023141108.856998818@telegraphics.com.au>
2011-10-23 14:11 ` Finn Thain [this message]
2011-11-24 14:34 ` [PATCH 01/16] pmac_zilog: fix unexpected irq Finn Thain
2011-11-24 14:56 ` Alan Cox
2011-11-24 20:41 ` Benjamin Herrenschmidt
2011-11-25 3:15 ` Finn Thain
2011-11-28 0:30 ` Benjamin Herrenschmidt
2011-11-24 15:28 ` David Laight
2011-11-24 20:43 ` Benjamin Herrenschmidt
2011-12-06 15:13 ` [PATCH 01/16 v2] " Finn Thain
2011-12-06 15:27 ` Geert Uytterhoeven
2011-12-07 1:26 ` Finn Thain
2011-12-06 15:39 ` Alan Cox
2011-12-07 3:49 ` [PATCH 01/16 v3] " Finn Thain
2011-12-08 3:17 ` Benjamin Herrenschmidt
2011-12-08 4:20 ` Benjamin Herrenschmidt
2011-12-08 4:30 ` Benjamin Herrenschmidt
2011-12-08 11:26 ` Finn Thain
2011-12-08 11:54 ` Geert Uytterhoeven
2011-12-08 19:44 ` Benjamin Herrenschmidt
2011-12-11 23:48 ` Benjamin Herrenschmidt
2011-12-11 23:55 ` Benjamin Herrenschmidt
2011-12-12 13:34 ` Finn Thain
2011-12-12 20:06 ` Benjamin Herrenschmidt
2011-12-13 1:24 ` Finn Thain
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