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"
16 #include <asm/sections.h>
18 #include <asm/mach_desc.h>
21 * Early Hardware specific Interrupt setup
22 * -Called very early (start_kernel -> setup_arch -> setup_processor)
23 * -Platform Independent (must for any ARC700)
24 * -Needed for each CPU (hence not foldable into init_IRQ)
27 * -setup Vector Table Base Reg - in case Linux not linked at 0x8000_0000
28 * -Disable all IRQs (on CPU side)
29 * -Optionally, setup the High priority Interrupts as Level 2 IRQs
31 void arc_init_IRQ(void)
35 /* Disable all IRQs: enable them as devices request */
36 write_aux_reg(AUX_IENABLE, 0);
38 /* setup any high priority Interrupts (Level2 in ARCompact jargon) */
39 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3;
40 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5;
41 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ6_LV2) << 6;
44 pr_info("Level-2 interrupts bitset %x\n", level_mask);
45 write_aux_reg(AUX_IRQ_LEV, level_mask);
50 * ARC700 core includes a simple on-chip intc supporting
51 * -per IRQ enable/disable
52 * -2 levels of interrupts (high/low)
53 * -all interrupts being level triggered
55 * To reduce platform code, we assume all IRQs directly hooked-up into intc.
56 * Platforms with external intc, hence cascaded IRQs, are free to over-ride
60 static void arc_mask_irq(struct irq_data *data)
62 arch_mask_irq(data->irq);
65 static void arc_unmask_irq(struct irq_data *data)
67 arch_unmask_irq(data->irq);
70 static struct irq_chip onchip_intc = {
71 .name = "ARC In-core Intc",
72 .irq_mask = arc_mask_irq,
73 .irq_unmask = arc_unmask_irq,
76 static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
79 if (irq == TIMER0_IRQ)
80 irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
82 irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
87 static const struct irq_domain_ops arc_intc_domain_ops = {
88 .xlate = irq_domain_xlate_onecell,
89 .map = arc_intc_domain_map,
92 static struct irq_domain *root_domain;
95 init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
98 panic("DeviceTree incore intc not a root irq controller\n");
100 root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0,
101 &arc_intc_domain_ops, NULL);
104 panic("root irq domain not avail\n");
106 /* with this we don't need to export root_domain */
107 irq_set_default_host(root_domain);
112 IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ);
115 * Late Interrupt system init called from start_kernel for Boot CPU only
117 * Since slab must already be initialized, platforms can start doing any
118 * needed request_irq( )s
120 void __init init_IRQ(void)
122 /* Any external intc can be setup here */
123 if (machine_desc->init_irq)
124 machine_desc->init_irq();
126 /* process the entire interrupt tree in one go */
130 /* Master CPU can initialize it's side of IPI */
131 if (machine_desc->init_smp)
132 machine_desc->init_smp(smp_processor_id());
137 * "C" Entry point for any ARC ISR, called from low level vector handler
138 * @irq is the vector number read from ICAUSE reg of on-chip intc
140 void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
142 struct pt_regs *old_regs = set_irq_regs(regs);
145 generic_handle_irq(irq);
147 set_irq_regs(old_regs);
150 int __init get_hw_config_num_irq(void)
152 uint32_t val = read_aux_reg(ARC_REG_VECBASE_BCR);
154 switch (val & 0x03) {
169 * arch_local_irq_enable - Enable interrupts.
171 * 1. Explicitly called to re-enable interrupts
172 * 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc
173 * which maybe in hard ISR itself
175 * Semantics of this function change depending on where it is called from:
177 * -If called from hard-ISR, it must not invert interrupt priorities
178 * e.g. suppose TIMER is high priority (Level 2) IRQ
179 * Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times.
180 * Here local_irq_enable( ) shd not re-enable lower priority interrupts
181 * -If called from soft-ISR, it must re-enable all interrupts
182 * soft ISR are low prioity jobs which can be very slow, thus all IRQs
183 * must be enabled while they run.
184 * Now hardware context wise we may still be in L2 ISR (not done rtie)
185 * still we must re-enable both L1 and L2 IRQs
186 * Another twist is prev scenario with flow being
187 * L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR
188 * here we must not re-enable Ll as prev Ll Interrupt's h/w context will get
189 * over-written (this is deficiency in ARC700 Interrupt mechanism)
192 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */
194 void arch_local_irq_enable(void)
198 flags = arch_local_save_flags();
200 /* Allow both L1 and L2 at the onset */
201 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
203 /* Called from hard ISR (between irq_enter and irq_exit) */
206 /* If in L2 ISR, don't re-enable any further IRQs as this can
207 * cause IRQ priorities to get upside down. e.g. it could allow
208 * L1 be taken while in L2 hard ISR which is wrong not only in
209 * theory, it can also cause the dreaded L1-L2-L1 scenario
211 if (flags & STATUS_A2_MASK)
212 flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK);
214 /* Even if in L1 ISR, allowe Higher prio L2 IRQs */
215 else if (flags & STATUS_A1_MASK)
216 flags &= ~(STATUS_E1_MASK);
219 /* called from soft IRQ, ideally we want to re-enable all levels */
221 else if (in_softirq()) {
223 /* However if this is case of L1 interrupted by L2,
224 * re-enabling both may cause whaco L1-L2-L1 scenario
225 * because ARC700 allows level 1 to interrupt an active L2 ISR
226 * Thus we disable both
227 * However some code, executing in soft ISR wants some IRQs
228 * to be enabled so we re-enable L2 only
230 * How do we determine L1 intr by L2
231 * -A2 is set (means in L2 ISR)
232 * -E1 is set in this ISR's pt_regs->status32 which is
233 * saved copy of status32_l2 when l2 ISR happened
235 struct pt_regs *pt = get_irq_regs();
236 if ((flags & STATUS_A2_MASK) && pt &&
237 (pt->status32 & STATUS_A1_MASK)) {
238 /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */
239 flags &= ~(STATUS_E1_MASK);
243 arch_local_irq_restore(flags);
246 #else /* ! CONFIG_ARC_COMPACT_IRQ_LEVELS */
249 * Simpler version for only 1 level of interrupt
250 * Here we only Worry about Level 1 Bits
252 void arch_local_irq_enable(void)
257 * ARC IDE Drivers tries to re-enable interrupts from hard-isr
258 * context which is simply wrong
261 WARN_ONCE(1, "IRQ enabled from hard-isr");
265 flags = arch_local_save_flags();
266 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
267 arch_local_irq_restore(flags);
270 EXPORT_SYMBOL(arch_local_irq_enable);