1 files changed, 280 insertions, 0 deletions
diff --git a/arch/tile/kernel/irq.c b/arch/tile/kernel/irq.c
new file mode 100644
index 000000000..22044fc69
--- /dev/null
+++ b/arch/tile/kernel/irq.c
@@ -0,0 +1,280 @@
+/*
+ * 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>
+#include <linux/perf_event.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 arch_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);
+
+#if CHIP_HAS_IPI()
+/* Use SPRs to manipulate device interrupts. */
+#define mask_irqs(irq_mask) __insn_mtspr(SPR_IPI_MASK_SET_K, irq_mask)
+#define unmask_irqs(irq_mask) __insn_mtspr(SPR_IPI_MASK_RESET_K, irq_mask)
+#define clear_irqs(irq_mask) __insn_mtspr(SPR_IPI_EVENT_RESET_K, 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 TILEPro, and IPI hardware on TILE-Gx.
+ * Entered with interrupts disabled.
+ */
+void tile_dev_intr(struct pt_regs *regs, int intnum)
+{
+	int depth = __this_cpu_inc_return(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_K);
+	original_irqs = __insn_mfspr(SPR_IPI_EVENT_K) & ~masked;
+	__insn_mtspr(SPR_IPI_MASK_SET_K, 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_K_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("%s: stack overflow: %ld\n",
+				 __func__, 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)
+			__this_cpu_inc(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 == 1)
+		unmask_irqs(~__this_cpu_read(irq_disable_mask));
+
+	__this_cpu_dec(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.
+ */
+static void tile_irq_chip_enable(struct irq_data *d)
+{
+	get_cpu_var(irq_disable_mask) &= ~(1UL << d->irq);
+	if (__this_cpu_read(irq_depth) == 0)
+		unmask_irqs(1UL << d->irq);
+	put_cpu_var(irq_disable_mask);
+}
+
+/*
+ * 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.
+ */
+static void tile_irq_chip_disable(struct irq_data *d)
+{
+	get_cpu_var(irq_disable_mask) |= (1UL << d->irq);
+	mask_irqs(1UL << d->irq);
+	put_cpu_var(irq_disable_mask);
+}
+
+/* Mask an interrupt. */
+static void tile_irq_chip_mask(struct irq_data *d)
+{
+	mask_irqs(1UL << d->irq);
+}
+
+/* Unmask an interrupt. */
+static void tile_irq_chip_unmask(struct irq_data *d)
+{
+	unmask_irqs(1UL << d->irq);
+}
+
+/*
+ * Clear an interrupt before processing it so that any new assertions
+ * will trigger another irq.
+ */
+static void tile_irq_chip_ack(struct irq_data *d)
+{
+	if ((unsigned long)irq_data_get_irq_chip_data(d) != IS_HW_CLEARED)
+		clear_irqs(1UL << d->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(struct irq_data *d)
+{
+	if (!(__this_cpu_read(irq_disable_mask) & (1UL << d->irq)))
+		unmask_irqs(1UL << d->irq);
+}
+
+static struct irq_chip tile_irq_chip = {
+	.name = "tile_irq_chip",
+	.irq_enable = tile_irq_chip_enable,
+	.irq_disable = tile_irq_chip_disable,
+	.irq_ack = tile_irq_chip_ack,
+	.irq_eoi = tile_irq_chip_eoi,
+	.irq_mask = tile_irq_chip_mask,
+	.irq_unmask = tile_irq_chip_unmask,
+};
+
+void __init init_IRQ(void)
+{
+	ipi_init();
+}
+
+void setup_irq_regs(void)
+{
+	/* Enable interrupt delivery. */
+	unmask_irqs(~0UL);
+#if CHIP_HAS_IPI()
+	arch_local_irq_unmask(INT_IPI_K);
+#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
+	 * 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;
+	irq_set_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)
+		irq_set_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);
+}
+
+/*
+ * /proc/interrupts printing:
+ */
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+#ifdef CONFIG_PERF_EVENTS
+	int i;
+
+	seq_printf(p, "%*s: ", prec, "PMI");
+
+	for_each_online_cpu(i)
+		seq_printf(p, "%10llu ", per_cpu(perf_irqs, i));
+	seq_puts(p, "  perf_events\n");
+#endif
+	return 0;
+}
+
+#if CHIP_HAS_IPI()
+int arch_setup_hwirq(unsigned int irq, int node)
+{
+	return irq >= NR_IRQS ? -EINVAL : 0;
+}
+
+void arch_teardown_hwirq(unsigned int irq) { }
+#endif