2 * Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com)
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
13 #include <linux/irqdomain.h>
14 #include <linux/irqchip.h>
15 #include "../../drivers/irqchip/irqchip.h"
19 * Early Hardware specific Interrupt setup
20 * -Platform independent, needed for each CPU (not foldable into init_IRQ)
21 * -Called very early (start_kernel -> setup_arch -> setup_processor)
24 * -Optionally, setup the High priority Interrupts as Level 2 IRQs
26 void arc_init_IRQ(void)
30 /* setup any high priority Interrupts (Level2 in ARCompact jargon) */
31 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3;
32 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5;
33 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ6_LV2) << 6;
36 * Write to register, even if no LV2 IRQs configured to reset it
37 * in case bootloader had mucked with it
39 write_aux_reg(AUX_IRQ_LEV, level_mask);
42 pr_info("Level-2 interrupts bitset %x\n", level_mask);
46 * ARC700 core includes a simple on-chip intc supporting
47 * -per IRQ enable/disable
48 * -2 levels of interrupts (high/low)
49 * -all interrupts being level triggered
51 * To reduce platform code, we assume all IRQs directly hooked-up into intc.
52 * Platforms with external intc, hence cascaded IRQs, are free to over-ride
56 static void arc_irq_mask(struct irq_data *data)
60 ienb = read_aux_reg(AUX_IENABLE);
61 ienb &= ~(1 << data->irq);
62 write_aux_reg(AUX_IENABLE, ienb);
65 static void arc_irq_unmask(struct irq_data *data)
69 ienb = read_aux_reg(AUX_IENABLE);
70 ienb |= (1 << data->irq);
71 write_aux_reg(AUX_IENABLE, ienb);
74 static struct irq_chip onchip_intc = {
75 .name = "ARC In-core Intc",
76 .irq_mask = arc_irq_mask,
77 .irq_unmask = arc_irq_unmask,
80 static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
84 * XXX: the IPI IRQ needs to be handled like TIMER too. However ARC core
85 * code doesn't own it (like TIMER0). ISS IDU / ezchip define it
86 * in platform header which can't be included here as it goes
87 * against multi-platform image philisophy
89 if (irq == TIMER0_IRQ)
90 irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
92 irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
97 static const struct irq_domain_ops arc_intc_domain_ops = {
98 .xlate = irq_domain_xlate_onecell,
99 .map = arc_intc_domain_map,
102 static struct irq_domain *root_domain;
105 init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
108 panic("DeviceTree incore intc not a root irq controller\n");
110 root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0,
111 &arc_intc_domain_ops, NULL);
114 panic("root irq domain not avail\n");
116 /* with this we don't need to export root_domain */
117 irq_set_default_host(root_domain);
122 IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ);
125 * arch_local_irq_enable - Enable interrupts.
127 * 1. Explicitly called to re-enable interrupts
128 * 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc
129 * which maybe in hard ISR itself
131 * Semantics of this function change depending on where it is called from:
133 * -If called from hard-ISR, it must not invert interrupt priorities
134 * e.g. suppose TIMER is high priority (Level 2) IRQ
135 * Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times.
136 * Here local_irq_enable( ) shd not re-enable lower priority interrupts
137 * -If called from soft-ISR, it must re-enable all interrupts
138 * soft ISR are low prioity jobs which can be very slow, thus all IRQs
139 * must be enabled while they run.
140 * Now hardware context wise we may still be in L2 ISR (not done rtie)
141 * still we must re-enable both L1 and L2 IRQs
142 * Another twist is prev scenario with flow being
143 * L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR
144 * here we must not re-enable Ll as prev Ll Interrupt's h/w context will get
145 * over-written (this is deficiency in ARC700 Interrupt mechanism)
148 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */
150 void arch_local_irq_enable(void)
153 unsigned long flags = arch_local_save_flags();
155 /* Allow both L1 and L2 at the onset */
156 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
158 /* Called from hard ISR (between irq_enter and irq_exit) */
161 /* If in L2 ISR, don't re-enable any further IRQs as this can
162 * cause IRQ priorities to get upside down. e.g. it could allow
163 * L1 be taken while in L2 hard ISR which is wrong not only in
164 * theory, it can also cause the dreaded L1-L2-L1 scenario
166 if (flags & STATUS_A2_MASK)
167 flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK);
169 /* Even if in L1 ISR, allowe Higher prio L2 IRQs */
170 else if (flags & STATUS_A1_MASK)
171 flags &= ~(STATUS_E1_MASK);
174 /* called from soft IRQ, ideally we want to re-enable all levels */
176 else if (in_softirq()) {
178 /* However if this is case of L1 interrupted by L2,
179 * re-enabling both may cause whaco L1-L2-L1 scenario
180 * because ARC700 allows level 1 to interrupt an active L2 ISR
181 * Thus we disable both
182 * However some code, executing in soft ISR wants some IRQs
183 * to be enabled so we re-enable L2 only
185 * How do we determine L1 intr by L2
186 * -A2 is set (means in L2 ISR)
187 * -E1 is set in this ISR's pt_regs->status32 which is
188 * saved copy of status32_l2 when l2 ISR happened
190 struct pt_regs *pt = get_irq_regs();
192 if ((flags & STATUS_A2_MASK) && pt &&
193 (pt->status32 & STATUS_A1_MASK)) {
194 /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */
195 flags &= ~(STATUS_E1_MASK);
199 arch_local_irq_restore(flags);
202 #else /* ! CONFIG_ARC_COMPACT_IRQ_LEVELS */
205 * Simpler version for only 1 level of interrupt
206 * Here we only Worry about Level 1 Bits
208 void arch_local_irq_enable(void)
213 * ARC IDE Drivers tries to re-enable interrupts from hard-isr
214 * context which is simply wrong
217 WARN_ONCE(1, "IRQ enabled from hard-isr");
221 flags = arch_local_save_flags();
222 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
223 arch_local_irq_restore(flags);
226 EXPORT_SYMBOL(arch_local_irq_enable);