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 * -Disable all IRQs (on CPU side)
28 * -Optionally, setup the High priority Interrupts as Level 2 IRQs
30 void arc_init_IRQ(void)
34 /* Disable all IRQs: enable them as devices request */
35 write_aux_reg(AUX_IENABLE, 0);
37 /* setup any high priority Interrupts (Level2 in ARCompact jargon) */
38 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3;
39 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5;
40 level_mask |= IS_ENABLED(CONFIG_ARC_IRQ6_LV2) << 6;
43 * Write to register, even if no LV2 IRQs configured to reset it
44 * in case bootloader had mucked with it
46 write_aux_reg(AUX_IRQ_LEV, level_mask);
49 pr_info("Level-2 interrupts bitset %x\n", level_mask);
53 * ARC700 core includes a simple on-chip intc supporting
54 * -per IRQ enable/disable
55 * -2 levels of interrupts (high/low)
56 * -all interrupts being level triggered
58 * To reduce platform code, we assume all IRQs directly hooked-up into intc.
59 * Platforms with external intc, hence cascaded IRQs, are free to over-ride
63 static void arc_mask_irq(struct irq_data *data)
65 arch_mask_irq(data->irq);
68 static void arc_unmask_irq(struct irq_data *data)
70 arch_unmask_irq(data->irq);
73 static struct irq_chip onchip_intc = {
74 .name = "ARC In-core Intc",
75 .irq_mask = arc_mask_irq,
76 .irq_unmask = arc_unmask_irq,
79 static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq,
82 if (irq == TIMER0_IRQ)
83 irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq);
85 irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq);
90 static const struct irq_domain_ops arc_intc_domain_ops = {
91 .xlate = irq_domain_xlate_onecell,
92 .map = arc_intc_domain_map,
95 static struct irq_domain *root_domain;
98 init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
101 panic("DeviceTree incore intc not a root irq controller\n");
103 root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0,
104 &arc_intc_domain_ops, NULL);
107 panic("root irq domain not avail\n");
109 /* with this we don't need to export root_domain */
110 irq_set_default_host(root_domain);
115 IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ);
118 * Late Interrupt system init called from start_kernel for Boot CPU only
120 * Since slab must already be initialized, platforms can start doing any
121 * needed request_irq( )s
123 void __init init_IRQ(void)
125 /* Any external intc can be setup here */
126 if (machine_desc->init_irq)
127 machine_desc->init_irq();
129 /* process the entire interrupt tree in one go */
133 /* Master CPU can initialize it's side of IPI */
134 if (machine_desc->init_smp)
135 machine_desc->init_smp(smp_processor_id());
140 * "C" Entry point for any ARC ISR, called from low level vector handler
141 * @irq is the vector number read from ICAUSE reg of on-chip intc
143 void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
145 struct pt_regs *old_regs = set_irq_regs(regs);
148 generic_handle_irq(irq);
150 set_irq_regs(old_regs);
154 * arch_local_irq_enable - Enable interrupts.
156 * 1. Explicitly called to re-enable interrupts
157 * 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc
158 * which maybe in hard ISR itself
160 * Semantics of this function change depending on where it is called from:
162 * -If called from hard-ISR, it must not invert interrupt priorities
163 * e.g. suppose TIMER is high priority (Level 2) IRQ
164 * Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times.
165 * Here local_irq_enable( ) shd not re-enable lower priority interrupts
166 * -If called from soft-ISR, it must re-enable all interrupts
167 * soft ISR are low prioity jobs which can be very slow, thus all IRQs
168 * must be enabled while they run.
169 * Now hardware context wise we may still be in L2 ISR (not done rtie)
170 * still we must re-enable both L1 and L2 IRQs
171 * Another twist is prev scenario with flow being
172 * L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR
173 * here we must not re-enable Ll as prev Ll Interrupt's h/w context will get
174 * over-written (this is deficiency in ARC700 Interrupt mechanism)
177 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */
179 void arch_local_irq_enable(void)
183 flags = arch_local_save_flags();
185 /* Allow both L1 and L2 at the onset */
186 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
188 /* Called from hard ISR (between irq_enter and irq_exit) */
191 /* If in L2 ISR, don't re-enable any further IRQs as this can
192 * cause IRQ priorities to get upside down. e.g. it could allow
193 * L1 be taken while in L2 hard ISR which is wrong not only in
194 * theory, it can also cause the dreaded L1-L2-L1 scenario
196 if (flags & STATUS_A2_MASK)
197 flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK);
199 /* Even if in L1 ISR, allowe Higher prio L2 IRQs */
200 else if (flags & STATUS_A1_MASK)
201 flags &= ~(STATUS_E1_MASK);
204 /* called from soft IRQ, ideally we want to re-enable all levels */
206 else if (in_softirq()) {
208 /* However if this is case of L1 interrupted by L2,
209 * re-enabling both may cause whaco L1-L2-L1 scenario
210 * because ARC700 allows level 1 to interrupt an active L2 ISR
211 * Thus we disable both
212 * However some code, executing in soft ISR wants some IRQs
213 * to be enabled so we re-enable L2 only
215 * How do we determine L1 intr by L2
216 * -A2 is set (means in L2 ISR)
217 * -E1 is set in this ISR's pt_regs->status32 which is
218 * saved copy of status32_l2 when l2 ISR happened
220 struct pt_regs *pt = get_irq_regs();
221 if ((flags & STATUS_A2_MASK) && pt &&
222 (pt->status32 & STATUS_A1_MASK)) {
223 /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */
224 flags &= ~(STATUS_E1_MASK);
228 arch_local_irq_restore(flags);
231 #else /* ! CONFIG_ARC_COMPACT_IRQ_LEVELS */
234 * Simpler version for only 1 level of interrupt
235 * Here we only Worry about Level 1 Bits
237 void arch_local_irq_enable(void)
242 * ARC IDE Drivers tries to re-enable interrupts from hard-isr
243 * context which is simply wrong
246 WARN_ONCE(1, "IRQ enabled from hard-isr");
250 flags = arch_local_save_flags();
251 flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
252 arch_local_irq_restore(flags);
255 EXPORT_SYMBOL(arch_local_irq_enable);