--- /dev/null
+/*
+ * Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip.h>
+#include "../../drivers/irqchip/irqchip.h"
+#include <asm/sections.h>
+#include <asm/irq.h>
+#include <asm/mach_desc.h>
+
+/*
+ * Early Hardware specific Interrupt setup
+ * -Platform independent, needed for each CPU (not foldable into init_IRQ)
+ * -Called very early (start_kernel -> setup_arch -> setup_processor)
+ *
+ * what it does ?
+ * -Optionally, setup the High priority Interrupts as Level 2 IRQs
+ */
+void arc_init_IRQ(void)
+{
+ int level_mask = 0;
+
+ /* setup any high priority Interrupts (Level2 in ARCompact jargon) */
+ level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3;
+ level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5;
+ level_mask |= IS_ENABLED(CONFIG_ARC_IRQ6_LV2) << 6;
+
+ /*
+ * Write to register, even if no LV2 IRQs configured to reset it
+ * in case bootloader had mucked with it
+ */
+ write_aux_reg(AUX_IRQ_LEV, level_mask);
+
+ if (level_mask)
+ pr_info("Level-2 interrupts bitset %x\n", level_mask);
+}
+
+/*
+ * ARC700 core includes a simple on-chip intc supporting
+ * -per IRQ enable/disable
+ * -2 levels of interrupts (high/low)
+ * -all interrupts being level triggered
+ *
+ * To reduce platform code, we assume all IRQs directly hooked-up into intc.
+ * Platforms with external intc, hence cascaded IRQs, are free to over-ride
+ * below, per IRQ.
+ */
+
+static void arc_irq_mask(struct irq_data *data)
+{
+ unsigned int ienb;
+
+ ienb = read_aux_reg(AUX_IENABLE);
+ ienb &= ~(1 << data->irq);
+ write_aux_reg(AUX_IENABLE, ienb);
+}
+
+static void arc_irq_unmask(struct irq_data *data)
+{
+ unsigned int ienb;
+
+ ienb = read_aux_reg(AUX_IENABLE);
+ ienb |= (1 << data->irq);
+ write_aux_reg(AUX_IENABLE, ienb);
+}
+
+static struct irq_chip onchip_intc = {
+ .name = "ARC In-core Intc",
+ .irq_mask = arc_irq_mask,
+ .irq_unmask = arc_irq_unmask,
+};
+
+static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hw)
+{
+ if (irq == TIMER0_IRQ)
+ irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
+ else
+ irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
+
+ return 0;
+}
+
+static const struct irq_domain_ops arc_intc_domain_ops = {
+ .xlate = irq_domain_xlate_onecell,
+ .map = arc_intc_domain_map,
+};
+
+static struct irq_domain *root_domain;
+
+static int __init
+init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
+{
+ if (parent)
+ panic("DeviceTree incore intc not a root irq controller\n");
+
+ root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0,
+ &arc_intc_domain_ops, NULL);
+
+ if (!root_domain)
+ panic("root irq domain not avail\n");
+
+ /* with this we don't need to export root_domain */
+ irq_set_default_host(root_domain);
+
+ return 0;
+}
+
+IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ);
+
+/*
+ * Late Interrupt system init called from start_kernel for Boot CPU only
+ *
+ * Since slab must already be initialized, platforms can start doing any
+ * needed request_irq( )s
+ */
+void __init init_IRQ(void)
+{
+ /* Any external intc can be setup here */
+ if (machine_desc->init_irq)
+ machine_desc->init_irq();
+
+ /* process the entire interrupt tree in one go */
+ irqchip_init();
+
+#ifdef CONFIG_SMP
+ /* Master CPU can initialize it's side of IPI */
+ if (machine_desc->init_smp)
+ machine_desc->init_smp(smp_processor_id());
+#endif
+}
+
+/*
+ * "C" Entry point for any ARC ISR, called from low level vector handler
+ * @irq is the vector number read from ICAUSE reg of on-chip intc
+ */
+void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+
+ irq_enter();
+ generic_handle_irq(irq);
+ irq_exit();
+ set_irq_regs(old_regs);
+}
+
+void arc_request_percpu_irq(int irq, int cpu,
+ irqreturn_t (*isr)(int irq, void *dev),
+ const char *irq_nm,
+ void *percpu_dev)
+{
+ /* Boot cpu calls request, all call enable */
+ if (!cpu) {
+ int rc;
+
+ /*
+ * These 2 calls are essential to making percpu IRQ APIs work
+ * Ideally these details could be hidden in irq chip map function
+ * but the issue is IPIs IRQs being static (non-DT) and platform
+ * specific, so we can't identify them there.
+ */
+ irq_set_percpu_devid(irq);
+ irq_modify_status(irq, IRQ_NOAUTOEN, 0); /* @irq, @clr, @set */
+
+ rc = request_percpu_irq(irq, isr, irq_nm, percpu_dev);
+ if (rc)
+ panic("Percpu IRQ request failed for %d\n", irq);
+ }
+
+ enable_percpu_irq(irq, 0);
+}
+
+/*
+ * arch_local_irq_enable - Enable interrupts.
+ *
+ * 1. Explicitly called to re-enable interrupts
+ * 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc
+ * which maybe in hard ISR itself
+ *
+ * Semantics of this function change depending on where it is called from:
+ *
+ * -If called from hard-ISR, it must not invert interrupt priorities
+ * e.g. suppose TIMER is high priority (Level 2) IRQ
+ * Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times.
+ * Here local_irq_enable( ) shd not re-enable lower priority interrupts
+ * -If called from soft-ISR, it must re-enable all interrupts
+ * soft ISR are low prioity jobs which can be very slow, thus all IRQs
+ * must be enabled while they run.
+ * Now hardware context wise we may still be in L2 ISR (not done rtie)
+ * still we must re-enable both L1 and L2 IRQs
+ * Another twist is prev scenario with flow being
+ * L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR
+ * here we must not re-enable Ll as prev Ll Interrupt's h/w context will get
+ * over-written (this is deficiency in ARC700 Interrupt mechanism)
+ */
+
+#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */
+
+void arch_local_irq_enable(void)
+{
+
+ unsigned long flags;
+ flags = arch_local_save_flags();
+
+ /* Allow both L1 and L2 at the onset */
+ flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
+
+ /* Called from hard ISR (between irq_enter and irq_exit) */
+ if (in_irq()) {
+
+ /* If in L2 ISR, don't re-enable any further IRQs as this can
+ * cause IRQ priorities to get upside down. e.g. it could allow
+ * L1 be taken while in L2 hard ISR which is wrong not only in
+ * theory, it can also cause the dreaded L1-L2-L1 scenario
+ */
+ if (flags & STATUS_A2_MASK)
+ flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK);
+
+ /* Even if in L1 ISR, allowe Higher prio L2 IRQs */
+ else if (flags & STATUS_A1_MASK)
+ flags &= ~(STATUS_E1_MASK);
+ }
+
+ /* called from soft IRQ, ideally we want to re-enable all levels */
+
+ else if (in_softirq()) {
+
+ /* However if this is case of L1 interrupted by L2,
+ * re-enabling both may cause whaco L1-L2-L1 scenario
+ * because ARC700 allows level 1 to interrupt an active L2 ISR
+ * Thus we disable both
+ * However some code, executing in soft ISR wants some IRQs
+ * to be enabled so we re-enable L2 only
+ *
+ * How do we determine L1 intr by L2
+ * -A2 is set (means in L2 ISR)
+ * -E1 is set in this ISR's pt_regs->status32 which is
+ * saved copy of status32_l2 when l2 ISR happened
+ */
+ struct pt_regs *pt = get_irq_regs();
+ if ((flags & STATUS_A2_MASK) && pt &&
+ (pt->status32 & STATUS_A1_MASK)) {
+ /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */
+ flags &= ~(STATUS_E1_MASK);
+ }
+ }
+
+ arch_local_irq_restore(flags);
+}
+
+#else /* ! CONFIG_ARC_COMPACT_IRQ_LEVELS */
+
+/*
+ * Simpler version for only 1 level of interrupt
+ * Here we only Worry about Level 1 Bits
+ */
+void arch_local_irq_enable(void)
+{
+ unsigned long flags;
+
+ /*
+ * ARC IDE Drivers tries to re-enable interrupts from hard-isr
+ * context which is simply wrong
+ */
+ if (in_irq()) {
+ WARN_ONCE(1, "IRQ enabled from hard-isr");
+ return;
+ }
+
+ flags = arch_local_save_flags();
+ flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
+ arch_local_irq_restore(flags);
+}
+#endif
+EXPORT_SYMBOL(arch_local_irq_enable);
Code Review / kvmfornfv.git / blobdiff