1 files changed, 334 insertions, 0 deletions
diff --git a/arch/tile/kernel/irq.c b/arch/tile/kernel/irq.c
new file mode 100644
index 000000000000..596c60086930
--- /dev/null
+++ b/arch/tile/kernel/irq.c
@@ -0,0 +1,334 @@
+/*
+ * 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>
+#include <arch/spr_def.h>
+#include <asm/traps.h>
+
+/* Bit-flag stored in irq_desc->chip_data to indicate HW-cleared irqs. */
+#define IS_HW_CLEARED 1
+
+/*
+ * 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 statistics state. */
+DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
+/*
+ * Define per-tile irq disable mask; the hardware/HV only has a single
+ * mask that we use to implement both masking and disabling.
+ */
+static DEFINE_PER_CPU(unsigned long, irq_disable_mask)
+	____cacheline_internodealigned_in_smp;
+
+/*
+ * Per-tile IRQ nesting depth.  Used to make sure we enable newly
+ * enabled IRQs before exiting the outermost interrupt.
+ */
+static DEFINE_PER_CPU(int, irq_depth);
+
+/* State for allocating IRQs on Gx. */
+#if CHIP_HAS_IPI()
+static unsigned long available_irqs = ~(1UL << IRQ_RESCHEDULE);
+static DEFINE_SPINLOCK(available_irqs_lock);
+#endif
+
+#if CHIP_HAS_IPI()
+/* Use SPRs to manipulate device interrupts. */
+#define mask_irqs(irq_mask) __insn_mtspr(SPR_IPI_MASK_SET_1, irq_mask)
+#define unmask_irqs(irq_mask) __insn_mtspr(SPR_IPI_MASK_RESET_1, irq_mask)
+#define clear_irqs(irq_mask) __insn_mtspr(SPR_IPI_EVENT_RESET_1, irq_mask)
+#else
+/* Use HV to manipulate device interrupts. */
+#define mask_irqs(irq_mask) hv_disable_intr(irq_mask)
+#define unmask_irqs(irq_mask) hv_enable_intr(irq_mask)
+#define clear_irqs(irq_mask) hv_clear_intr(irq_mask)
+#endif
+
+/*
+ * The interrupt handling path, implemented in terms of HV interrupt
+ * emulation on TILE64 and TILEPro, and IPI hardware on TILE-Gx.
+ */
+void tile_dev_intr(struct pt_regs *regs, int intnum)
+{
+	int depth = __get_cpu_var(irq_depth)++;
+	unsigned long original_irqs;
+	unsigned long remaining_irqs;
+	struct pt_regs *old_regs;
+
+#if CHIP_HAS_IPI()
+	/*
+	 * Pending interrupts are listed in an SPR.  We might be
+	 * nested, so be sure to only handle irqs that weren't already
+	 * masked by a previous interrupt.  Then, mask out the ones
+	 * we're going to handle.
+	 */
+	unsigned long masked = __insn_mfspr(SPR_IPI_MASK_1);
+	original_irqs = __insn_mfspr(SPR_IPI_EVENT_1) & ~masked;
+	__insn_mtspr(SPR_IPI_MASK_SET_1, original_irqs);
+#else
+	/*
+	 * Hypervisor performs the equivalent of the Gx code above and
+	 * then puts the pending interrupt mask into a system save reg
+	 * for us to find.
+	 */
+	original_irqs = __insn_mfspr(SPR_SYSTEM_SAVE_1_3);
+#endif
+	remaining_irqs = original_irqs;
+
+	/* Track time spent here in an interrupt context. */
+	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))) {
+			pr_emerg("tile_dev_intr: "
+			       "stack overflow: %ld\n",
+			       sp - sizeof(struct thread_info));
+			dump_stack();
+		}
+	}
+#endif
+	while (remaining_irqs) {
+		unsigned long irq = __ffs(remaining_irqs);
+		remaining_irqs &= ~(1UL << irq);
+
+		/* Count device irqs; Linux IPIs are counted elsewhere. */
+		if (irq != IRQ_RESCHEDULE)
+			__get_cpu_var(irq_stat).irq_dev_intr_count++;
+
+		generic_handle_irq(irq);
+	}
+
+	/*
+	 * If we weren't nested, turn on all enabled interrupts,
+	 * including any that were reenabled during interrupt
+	 * handling.
+	 */
+	if (depth == 0)
+		unmask_irqs(~__get_cpu_var(irq_disable_mask));
+
+	__get_cpu_var(irq_depth)--;
+
+	/*
+	 * Track time spent against the current process again and
+	 * process any softirqs if they are waiting.
+	 */
+	irq_exit();
+	set_irq_regs(old_regs);
+}
+
+
+/*
+ * Remove an irq from the disabled mask.  If we're in an interrupt
+ * context, defer enabling the HW interrupt until we leave.
+ */
+void enable_percpu_irq(unsigned int irq)
+{
+	get_cpu_var(irq_disable_mask) &= ~(1UL << irq);
+	if (__get_cpu_var(irq_depth) == 0)
+		unmask_irqs(1UL << irq);
+	put_cpu_var(irq_disable_mask);
+}
+EXPORT_SYMBOL(enable_percpu_irq);
+
+/*
+ * Add an irq to the disabled mask.  We disable the HW interrupt
+ * immediately so that there's no possibility of it firing.  If we're
+ * in an interrupt context, the return path is careful to avoid
+ * unmasking a newly disabled interrupt.
+ */
+void disable_percpu_irq(unsigned int irq)
+{
+	get_cpu_var(irq_disable_mask) |= (1UL << irq);
+	mask_irqs(1UL << irq);
+	put_cpu_var(irq_disable_mask);
+}
+EXPORT_SYMBOL(disable_percpu_irq);
+
+/* Mask an interrupt. */
+static void tile_irq_chip_mask(unsigned int irq)
+{
+	mask_irqs(1UL << irq);
+}
+
+/* Unmask an interrupt. */
+static void tile_irq_chip_unmask(unsigned int irq)
+{
+	unmask_irqs(1UL << irq);
+}
+
+/*
+ * Clear an interrupt before processing it so that any new assertions
+ * will trigger another irq.
+ */
+static void tile_irq_chip_ack(unsigned int irq)
+{
+	if ((unsigned long)get_irq_chip_data(irq) != IS_HW_CLEARED)
+		clear_irqs(1UL << irq);
+}
+
+/*
+ * For per-cpu interrupts, we need to avoid unmasking any interrupts
+ * that we disabled via disable_percpu_irq().
+ */
+static void tile_irq_chip_eoi(unsigned int irq)
+{
+	if (!(__get_cpu_var(irq_disable_mask) & (1UL << irq)))
+		unmask_irqs(1UL << irq);
+}
+
+static struct irq_chip tile_irq_chip = {
+	.typename = "tile_irq_chip",
+	.ack = tile_irq_chip_ack,
+	.eoi = tile_irq_chip_eoi,
+	.mask = tile_irq_chip_mask,
+	.unmask = tile_irq_chip_unmask,
+};
+
+void __init init_IRQ(void)
+{
+	ipi_init();
+}
+
+void __cpuinit setup_irq_regs(void)
+{
+	/* Enable interrupt delivery. */
+	unmask_irqs(~0UL);
+#if CHIP_HAS_IPI()
+	raw_local_irq_unmask(INT_IPI_1);
+#endif
+}
+
+void tile_irq_activate(unsigned int irq, int tile_irq_type)
+{
+	/*
+	 * We use handle_level_irq() by default because the pending
+	 * interrupt vector (whether modeled by the HV on TILE64 and
+	 * TILEPro or implemented in hardware on TILE-Gx) has
+	 * level-style semantics for each bit.  An interrupt fires
+	 * whenever a bit is high, not just at edges.
+	 */
+	irq_flow_handler_t handle = handle_level_irq;
+	if (tile_irq_type == TILE_IRQ_PERCPU)
+		handle = handle_percpu_irq;
+	set_irq_chip_and_handler(irq, &tile_irq_chip, handle);
+
+	/*
+	 * Flag interrupts that are hardware-cleared so that ack()
+	 * won't clear them.
+	 */
+	if (tile_irq_type == TILE_IRQ_HW_CLEAR)
+		set_irq_chip_data(irq, (void *)IS_HW_CLEARED);
+}
+EXPORT_SYMBOL(tile_irq_activate);
+
+
+void ack_bad_irq(unsigned int irq)
+{
+	pr_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;
+}
+
+#if CHIP_HAS_IPI()
+int create_irq(void)
+{
+	unsigned long flags;
+	int result;
+
+	spin_lock_irqsave(&available_irqs_lock, flags);
+	if (available_irqs == 0)
+		result = -ENOMEM;
+	else {
+		result = __ffs(available_irqs);
+		available_irqs &= ~(1UL << result);
+		dynamic_irq_init(result);
+	}
+	spin_unlock_irqrestore(&available_irqs_lock, flags);
+
+	return result;
+}
+EXPORT_SYMBOL(create_irq);
+
+void destroy_irq(unsigned int irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&available_irqs_lock, flags);
+	available_irqs |= (1UL << irq);
+	dynamic_irq_cleanup(irq);
+	spin_unlock_irqrestore(&available_irqs_lock, flags);
+}
+EXPORT_SYMBOL(destroy_irq);
+#endif