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- /*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- * 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, version 2.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT. See the GNU General Public License for
- * more details.
- */
- #include <linux/module.h>
- #include <linux/seq_file.h>
- #include <linux/interrupt.h>
- #include <linux/irq.h>
- #include <linux/kernel_stat.h>
- #include <linux/uaccess.h>
- #include <hv/drv_pcie_rc_intf.h>
- /*
- * The set of interrupts we enable for raw_local_irq_enable().
- * This is initialized to have just a single interrupt that the kernel
- * doesn't actually use as a sentinel. During kernel init,
- * interrupts are added as the kernel gets prepared to support them.
- * NOTE: we could probably initialize them all statically up front.
- */
- DEFINE_PER_CPU(unsigned long long, interrupts_enabled_mask) =
- INITIAL_INTERRUPTS_ENABLED;
- EXPORT_PER_CPU_SYMBOL(interrupts_enabled_mask);
- /* Define per-tile device interrupt state */
- DEFINE_PER_CPU(HV_IntrState, dev_intr_state);
- DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
- EXPORT_PER_CPU_SYMBOL(irq_stat);
- /*
- * Interrupt dispatcher, invoked upon a hypervisor device interrupt downcall
- */
- void tile_dev_intr(struct pt_regs *regs, int intnum)
- {
- int irq;
- /*
- * Get the device interrupt pending mask from where the hypervisor
- * has tucked it away for us.
- */
- unsigned long pending_dev_intr_mask = __insn_mfspr(SPR_SYSTEM_SAVE_1_3);
- /* Track time spent here in an interrupt context. */
- struct pt_regs *old_regs = set_irq_regs(regs);
- irq_enter();
- #ifdef CONFIG_DEBUG_STACKOVERFLOW
- /* Debugging check for stack overflow: less than 1/8th stack free? */
- {
- long sp = stack_pointer - (long) current_thread_info();
- if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
- printk(KERN_EMERG "tile_dev_intr: "
- "stack overflow: %ld\n",
- sp - sizeof(struct thread_info));
- dump_stack();
- }
- }
- #endif
- for (irq = 0; pending_dev_intr_mask; ++irq) {
- if (pending_dev_intr_mask & 0x1) {
- generic_handle_irq(irq);
- /* Count device irqs; IPIs are counted elsewhere. */
- if (irq > HV_MAX_IPI_INTERRUPT)
- __get_cpu_var(irq_stat).irq_dev_intr_count++;
- }
- pending_dev_intr_mask >>= 1;
- }
- /*
- * Track time spent against the current process again and
- * process any softirqs if they are waiting.
- */
- irq_exit();
- set_irq_regs(old_regs);
- }
- /* Mask an interrupt. */
- static void hv_dev_irq_mask(unsigned int irq)
- {
- HV_IntrState *p_intr_state = &__get_cpu_var(dev_intr_state);
- hv_disable_intr(p_intr_state, 1 << irq);
- }
- /* Unmask an interrupt. */
- static void hv_dev_irq_unmask(unsigned int irq)
- {
- /* Re-enable the hypervisor to generate interrupts. */
- HV_IntrState *p_intr_state = &__get_cpu_var(dev_intr_state);
- hv_enable_intr(p_intr_state, 1 << irq);
- }
- /*
- * The HV doesn't latch incoming interrupts while an interrupt is
- * disabled, so we need to reenable interrupts before running the
- * handler.
- *
- * ISSUE: Enabling the interrupt this early avoids any race conditions
- * but introduces the possibility of nested interrupt stack overflow.
- * An imminent change to the HV IRQ model will fix this.
- */
- static void hv_dev_irq_ack(unsigned int irq)
- {
- hv_dev_irq_unmask(irq);
- }
- /*
- * Since ack() reenables interrupts, there's nothing to do at eoi().
- */
- static void hv_dev_irq_eoi(unsigned int irq)
- {
- }
- static struct irq_chip hv_dev_irq_chip = {
- .typename = "hv_dev_irq_chip",
- .ack = hv_dev_irq_ack,
- .mask = hv_dev_irq_mask,
- .unmask = hv_dev_irq_unmask,
- .eoi = hv_dev_irq_eoi,
- };
- static struct irqaction resched_action = {
- .handler = handle_reschedule_ipi,
- .name = "resched",
- .dev_id = handle_reschedule_ipi /* unique token */,
- };
- void __init init_IRQ(void)
- {
- /* Bind IPI irqs. Does this belong somewhere else in init? */
- tile_irq_activate(IRQ_RESCHEDULE);
- BUG_ON(setup_irq(IRQ_RESCHEDULE, &resched_action));
- }
- void __cpuinit init_per_tile_IRQs(void)
- {
- int rc;
- /* Set the pointer to the per-tile device interrupt state. */
- HV_IntrState *sv_ptr = &__get_cpu_var(dev_intr_state);
- rc = hv_dev_register_intr_state(sv_ptr);
- if (rc != HV_OK)
- panic("hv_dev_register_intr_state: error %d", rc);
- }
- void tile_irq_activate(unsigned int irq)
- {
- /*
- * Paravirtualized drivers can call up to the HV to find out
- * which irq they're associated with. The HV interface
- * doesn't provide a generic call for discovering all valid
- * IRQs, so drivers must call this method to initialize newly
- * discovered IRQs.
- *
- * We could also just initialize all 32 IRQs at startup, but
- * doing so would lead to a kernel fault if an unexpected
- * interrupt fires and jumps to a NULL action. By defering
- * the set_irq_chip_and_handler() call, unexpected IRQs are
- * handled properly by handle_bad_irq().
- */
- hv_dev_irq_mask(irq);
- set_irq_chip_and_handler(irq, &hv_dev_irq_chip, handle_percpu_irq);
- }
- void ack_bad_irq(unsigned int irq)
- {
- printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
- }
- /*
- * Generic, controller-independent functions:
- */
- int show_interrupts(struct seq_file *p, void *v)
- {
- int i = *(loff_t *) v, j;
- struct irqaction *action;
- unsigned long flags;
- if (i == 0) {
- seq_printf(p, " ");
- for (j = 0; j < NR_CPUS; j++)
- if (cpu_online(j))
- seq_printf(p, "CPU%-8d", j);
- seq_putc(p, '\n');
- }
- if (i < NR_IRQS) {
- raw_spin_lock_irqsave(&irq_desc[i].lock, flags);
- action = irq_desc[i].action;
- if (!action)
- goto skip;
- seq_printf(p, "%3d: ", i);
- #ifndef CONFIG_SMP
- seq_printf(p, "%10u ", kstat_irqs(i));
- #else
- for_each_online_cpu(j)
- seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
- #endif
- seq_printf(p, " %14s", irq_desc[i].chip->typename);
- seq_printf(p, " %s", action->name);
- for (action = action->next; action; action = action->next)
- seq_printf(p, ", %s", action->name);
- seq_putc(p, '\n');
- skip:
- raw_spin_unlock_irqrestore(&irq_desc[i].lock, flags);
- }
- return 0;
- }
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