diff options
Diffstat (limited to 'arch/m68k/mac/oss.c')
| -rw-r--r-- | arch/m68k/mac/oss.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/m68k/mac/oss.c b/arch/m68k/mac/oss.c new file mode 100644 index 000000000..921e6c092 --- /dev/null +++ b/arch/m68k/mac/oss.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/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 + */ + +void __init oss_init(void) +{ + int i; + + if (macintosh_config->ident != MAC_MODEL_IIFX) + return; + + oss = (struct mac_oss *) OSS_BASE; + pr_debug("OSS detected at %p", oss); + oss_present = 1; + + /* 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; +} + +/* + * Handle OSS interrupts. + * XXX how do you clear a pending IRQ? is it even necessary? + */ + +static void oss_iopism_irq(struct irq_desc *desc) +{ + generic_handle_irq(IRQ_MAC_ADB); +} + +static void oss_scsi_irq(struct irq_desc *desc) +{ + generic_handle_irq(IRQ_MAC_SCSI); +} + +static void oss_nubus_irq(struct irq_desc *desc) +{ + u16 events, irq_bit; + int irq_num; + + events = oss->irq_pending & OSS_IP_NUBUS; + irq_num = NUBUS_SOURCE_BASE + 5; + irq_bit = OSS_IP_NUBUS5; + do { + if (events & irq_bit) { + events &= ~irq_bit; + generic_handle_irq(irq_num); + } + --irq_num; + irq_bit >>= 1; + } while (events); +} + +static void oss_iopscc_irq(struct irq_desc *desc) +{ + generic_handle_irq(IRQ_MAC_SCC); +} + +/* + * 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_iopism_irq); + irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_scsi_irq); + irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq); + irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_iopscc_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] = OSS_IRQLEV_VIA1; +} + +/* + * 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) { + 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) { + 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); +} |