diff options
Diffstat (limited to 'arch/openrisc/kernel/irq.c')
| -rw-r--r-- | arch/openrisc/kernel/irq.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/openrisc/kernel/irq.c b/arch/openrisc/kernel/irq.c new file mode 100644 index 00000000000..8ec77bc9f1e --- /dev/null +++ b/arch/openrisc/kernel/irq.c @@ -0,0 +1,186 @@ +/* + * OpenRISC irq.c + * + * Linux architectural port borrowing liberally from similar works of + * others. All original copyrights apply as per the original source + * declaration. + * + * Modifications for the OpenRISC architecture: + * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/of.h> +#include <linux/ftrace.h> +#include <linux/irq.h> +#include <linux/export.h> +#include <linux/irqdomain.h> +#include <linux/irqflags.h> + +/* read interrupt enabled status */ +unsigned long arch_local_save_flags(void) +{ + return mfspr(SPR_SR) & (SPR_SR_IEE|SPR_SR_TEE); +} +EXPORT_SYMBOL(arch_local_save_flags); + +/* set interrupt enabled status */ +void arch_local_irq_restore(unsigned long flags) +{ + mtspr(SPR_SR, ((mfspr(SPR_SR) & ~(SPR_SR_IEE|SPR_SR_TEE)) | flags)); +} +EXPORT_SYMBOL(arch_local_irq_restore); + + +/* OR1K PIC implementation */ + +/* We're a couple of cycles faster than the generic implementations with + * these 'fast' versions. + */ + +static void or1k_pic_mask(struct irq_data *data) +{ + mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq)); +} + +static void or1k_pic_unmask(struct irq_data *data) +{ + mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->hwirq)); +} + +static void or1k_pic_ack(struct irq_data *data) +{ + /* EDGE-triggered interrupts need to be ack'ed in order to clear + * the latch. + * LEVEL-triggered interrupts do not need to be ack'ed; however, + * ack'ing the interrupt has no ill-effect and is quicker than + * trying to figure out what type it is... + */ + + /* The OpenRISC 1000 spec says to write a 1 to the bit to ack the + * interrupt, but the OR1200 does this backwards and requires a 0 + * to be written... + */ + +#ifdef CONFIG_OR1K_1200 + /* There are two oddities with the OR1200 PIC implementation: + * i) LEVEL-triggered interrupts are latched and need to be cleared + * ii) the interrupt latch is cleared by writing a 0 to the bit, + * as opposed to a 1 as mandated by the spec + */ + + mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq)); +#else + WARN(1, "Interrupt handling possibly broken\n"); + mtspr(SPR_PICSR, (1UL << data->hwirq)); +#endif +} + +static void or1k_pic_mask_ack(struct irq_data *data) +{ + /* Comments for pic_ack apply here, too */ + +#ifdef CONFIG_OR1K_1200 + mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq)); + mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq)); +#else + WARN(1, "Interrupt handling possibly broken\n"); + mtspr(SPR_PICMR, (1UL << data->hwirq)); + mtspr(SPR_PICSR, (1UL << data->hwirq)); +#endif +} + +#if 0 +static int or1k_pic_set_type(struct irq_data *data, unsigned int flow_type) +{ + /* There's nothing to do in the PIC configuration when changing + * flow type. Level and edge-triggered interrupts are both + * supported, but it's PIC-implementation specific which type + * is handled. */ + + return irq_setup_alt_chip(data, flow_type); +} +#endif + +static struct irq_chip or1k_dev = { + .name = "or1k-PIC", + .irq_unmask = or1k_pic_unmask, + .irq_mask = or1k_pic_mask, + .irq_ack = or1k_pic_ack, + .irq_mask_ack = or1k_pic_mask_ack, +}; + +static struct irq_domain *root_domain; + +static inline int pic_get_irq(int first) +{ + int hwirq; + + hwirq = ffs(mfspr(SPR_PICSR) >> first); + if (!hwirq) + return NO_IRQ; + else + hwirq = hwirq + first -1; + + return irq_find_mapping(root_domain, hwirq); +} + + +static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) +{ + irq_set_chip_and_handler_name(irq, &or1k_dev, + handle_level_irq, "level"); + irq_set_status_flags(irq, IRQ_LEVEL | IRQ_NOPROBE); + + return 0; +} + +static const struct irq_domain_ops or1k_irq_domain_ops = { + .xlate = irq_domain_xlate_onecell, + .map = or1k_map, +}; + +/* + * This sets up the IRQ domain for the PIC built in to the OpenRISC + * 1000 CPU. This is the "root" domain as these are the interrupts + * that directly trigger an exception in the CPU. + */ +static void __init or1k_irq_init(void) +{ + struct device_node *intc = NULL; + + /* The interrupt controller device node is mandatory */ + intc = of_find_compatible_node(NULL, NULL, "opencores,or1k-pic"); + BUG_ON(!intc); + + /* Disable all interrupts until explicitly requested */ + mtspr(SPR_PICMR, (0UL)); + + root_domain = irq_domain_add_linear(intc, 32, + &or1k_irq_domain_ops, NULL); +} + +void __init init_IRQ(void) +{ + or1k_irq_init(); +} + +void __irq_entry do_IRQ(struct pt_regs *regs) +{ + int irq = -1; + struct pt_regs *old_regs = set_irq_regs(regs); + + irq_enter(); + + while ((irq = pic_get_irq(irq + 1)) != NO_IRQ) + generic_handle_irq(irq); + + irq_exit(); + set_irq_regs(old_regs); +} |