linux-stable/arch/m68k/mac/oss.c
Finn Thain da3fb3c9aa m68k/mac: oss irq fixes
The IOP driver calls into the OSS driver to enable its IRQ. This undesirable coupling between drivers only exists because the OSS driver doesn't correctly handle all of its machspec IRQs.

Fix OSS handling of enable/disable for VIA1 IRQs (8 thru 15) which includes MAC_IRQ_ADB.

Back when I implemented pmac_zilog support I redefined IRQ_MAC_SCC incorrectly. Change this to a machspec IRQ so that it works on OSS.

Clean up the unused OSS audio IRQ and OSS_IRQLEV_* cruft that only confuses things.

Fix the OSS description in macints.c and remove an obsolete comment.

Don't enable the VIA1 irq before registering the handler.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2011-12-10 19:52:47 +01:00

228 lines
5.3 KiB
C

/*
* Operating System Services (OSS) chip handling
* Written by Joshua M. Thompson (funaho@jurai.org)
*
*
* This chip is used in the IIfx in place of VIA #2. It acts like a fancy
* VIA chip with prorammable interrupt levels.
*
* 990502 (jmt) - Major rewrite for new interrupt architecture as well as some
* recent insights into OSS operational details.
* 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped
* to mostly match the A/UX interrupt scheme supported on the
* VIA side. Also added support for enabling the ISM irq again
* since we now have a functional IOP manager.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <asm/bootinfo.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_via.h>
#include <asm/mac_oss.h>
int oss_present;
volatile struct mac_oss *oss;
/*
* Initialize the OSS
*
* The OSS "detection" code is actually in via_init() which is always called
* before us. Thus we can count on oss_present being valid on entry.
*/
void __init oss_init(void)
{
int i;
if (!oss_present) return;
oss = (struct mac_oss *) OSS_BASE;
/* Disable all interrupts. Unlike a VIA it looks like we */
/* do this by setting the source's interrupt level to zero. */
for (i = 0; i <= OSS_NUM_SOURCES; i++) {
oss->irq_level[i] = 0;
}
}
/*
* Initialize OSS for Nubus access
*/
void __init oss_nubus_init(void)
{
}
/*
* Handle miscellaneous OSS interrupts.
*/
static void oss_irq(unsigned int irq, struct irq_desc *desc)
{
int events = oss->irq_pending &
(OSS_IP_IOPSCC | OSS_IP_SCSI | OSS_IP_IOPISM);
#ifdef DEBUG_IRQS
if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
printk("oss_irq: irq %u events = 0x%04X\n", irq,
(int) oss->irq_pending);
}
#endif
if (events & OSS_IP_IOPSCC) {
oss->irq_pending &= ~OSS_IP_IOPSCC;
generic_handle_irq(IRQ_MAC_SCC);
}
if (events & OSS_IP_SCSI) {
oss->irq_pending &= ~OSS_IP_SCSI;
generic_handle_irq(IRQ_MAC_SCSI);
}
if (events & OSS_IP_IOPISM) {
oss->irq_pending &= ~OSS_IP_IOPISM;
generic_handle_irq(IRQ_MAC_ADB);
}
}
/*
* Nubus IRQ handler, OSS style
*
* Unlike the VIA/RBV this is on its own autovector interrupt level.
*/
static void oss_nubus_irq(unsigned int irq, struct irq_desc *desc)
{
int events, irq_bit, i;
events = oss->irq_pending & OSS_IP_NUBUS;
if (!events)
return;
#ifdef DEBUG_NUBUS_INT
if (console_loglevel > 7) {
printk("oss_nubus_irq: events = 0x%04X\n", events);
}
#endif
/* There are only six slots on the OSS, not seven */
i = 6;
irq_bit = 0x40;
do {
--i;
irq_bit >>= 1;
if (events & irq_bit) {
oss->irq_pending &= ~irq_bit;
generic_handle_irq(NUBUS_SOURCE_BASE + i);
}
} while(events & (irq_bit - 1));
}
/*
* Register the OSS and NuBus interrupt dispatchers.
*
* This IRQ mapping is laid out with two things in mind: first, we try to keep
* things on their own levels to avoid having to do double-dispatches. Second,
* the levels match as closely as possible the alternate IRQ mapping mode (aka
* "A/UX mode") available on some VIA machines.
*/
#define OSS_IRQLEV_IOPISM IRQ_AUTO_1
#define OSS_IRQLEV_SCSI IRQ_AUTO_2
#define OSS_IRQLEV_NUBUS IRQ_AUTO_3
#define OSS_IRQLEV_IOPSCC IRQ_AUTO_4
#define OSS_IRQLEV_VIA1 IRQ_AUTO_6
void __init oss_register_interrupts(void)
{
irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_irq);
irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_irq);
irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq);
irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_irq);
irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq);
/* OSS_VIA1 gets enabled here because it has no machspec interrupt. */
oss->irq_level[OSS_VIA1] = IRQ_AUTO_6;
}
/*
* Enable an OSS interrupt
*
* It looks messy but it's rather straightforward. The switch() statement
* just maps the machspec interrupt numbers to the right OSS interrupt
* source (if the OSS handles that interrupt) and then sets the interrupt
* level for that source to nonzero, thus enabling the interrupt.
*/
void oss_irq_enable(int irq) {
#ifdef DEBUG_IRQUSE
printk("oss_irq_enable(%d)\n", irq);
#endif
switch(irq) {
case IRQ_MAC_SCC:
oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
return;
case IRQ_MAC_ADB:
oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
return;
case IRQ_MAC_SCSI:
oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
return;
case IRQ_NUBUS_9:
case IRQ_NUBUS_A:
case IRQ_NUBUS_B:
case IRQ_NUBUS_C:
case IRQ_NUBUS_D:
case IRQ_NUBUS_E:
irq -= NUBUS_SOURCE_BASE;
oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
return;
}
if (IRQ_SRC(irq) == 1)
via_irq_enable(irq);
}
/*
* Disable an OSS interrupt
*
* Same as above except we set the source's interrupt level to zero,
* to disable the interrupt.
*/
void oss_irq_disable(int irq) {
#ifdef DEBUG_IRQUSE
printk("oss_irq_disable(%d)\n", irq);
#endif
switch(irq) {
case IRQ_MAC_SCC:
oss->irq_level[OSS_IOPSCC] = 0;
return;
case IRQ_MAC_ADB:
oss->irq_level[OSS_IOPISM] = 0;
return;
case IRQ_MAC_SCSI:
oss->irq_level[OSS_SCSI] = 0;
return;
case IRQ_NUBUS_9:
case IRQ_NUBUS_A:
case IRQ_NUBUS_B:
case IRQ_NUBUS_C:
case IRQ_NUBUS_D:
case IRQ_NUBUS_E:
irq -= NUBUS_SOURCE_BASE;
oss->irq_level[irq] = 0;
return;
}
if (IRQ_SRC(irq) == 1)
via_irq_disable(irq);
}