1 /*
2  * Marvell Armada 370 and Armada XP SoC IRQ handling
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Lior Amsalem <alior@marvell.com>
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  * Ben Dooks <ben.dooks@codethink.co.uk>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2.  This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/irq.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/of_address.h>
23 #include <linux/of_irq.h>
24 #include <linux/irqdomain.h>
25 #include <asm/mach/arch.h>
26 #include <asm/exception.h>
27 #include <asm/smp_plat.h>
28 #include <asm/mach/irq.h>
29 
30 #include "irqchip.h"
31 
32 /* Interrupt Controller Registers Map */
33 #define ARMADA_370_XP_INT_SET_MASK_OFFS		(0x48)
34 #define ARMADA_370_XP_INT_CLEAR_MASK_OFFS	(0x4C)
35 
36 #define ARMADA_370_XP_INT_CONTROL		(0x00)
37 #define ARMADA_370_XP_INT_SET_ENABLE_OFFS	(0x30)
38 #define ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS	(0x34)
39 #define ARMADA_370_XP_INT_SOURCE_CTL(irq)	(0x100 + irq*4)
40 
41 #define ARMADA_370_XP_CPU_INTACK_OFFS		(0x44)
42 
43 #define ARMADA_370_XP_SW_TRIG_INT_OFFS           (0x4)
44 #define ARMADA_370_XP_IN_DRBEL_MSK_OFFS          (0xc)
45 #define ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS        (0x8)
46 
47 #define ARMADA_370_XP_MAX_PER_CPU_IRQS		(28)
48 
49 #define ARMADA_370_XP_TIMER0_PER_CPU_IRQ	(5)
50 
51 #define IPI_DOORBELL_START                      (0)
52 #define IPI_DOORBELL_END                        (8)
53 #define IPI_DOORBELL_MASK                       0xFF
54 
55 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
56 
57 static void __iomem *per_cpu_int_base;
58 static void __iomem *main_int_base;
59 static struct irq_domain *armada_370_xp_mpic_domain;
60 
61 /*
62  * In SMP mode:
63  * For shared global interrupts, mask/unmask global enable bit
64  * For CPU interrupts, mask/unmask the calling CPU's bit
65  */
66 static void armada_370_xp_irq_mask(struct irq_data *d)
67 {
68 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
69 
70 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
71 		writel(hwirq, main_int_base +
72 				ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);
73 	else
74 		writel(hwirq, per_cpu_int_base +
75 				ARMADA_370_XP_INT_SET_MASK_OFFS);
76 }
77 
78 static void armada_370_xp_irq_unmask(struct irq_data *d)
79 {
80 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
81 
82 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
83 		writel(hwirq, main_int_base +
84 				ARMADA_370_XP_INT_SET_ENABLE_OFFS);
85 	else
86 		writel(hwirq, per_cpu_int_base +
87 				ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
88 }
89 
90 #ifdef CONFIG_SMP
91 static int armada_xp_set_affinity(struct irq_data *d,
92 				  const struct cpumask *mask_val, bool force)
93 {
94 	unsigned long reg;
95 	unsigned long new_mask = 0;
96 	unsigned long online_mask = 0;
97 	unsigned long count = 0;
98 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
99 	int cpu;
100 
101 	for_each_cpu(cpu, mask_val) {
102 		new_mask |= 1 << cpu_logical_map(cpu);
103 		count++;
104 	}
105 
106 	/*
107 	 * Forbid mutlicore interrupt affinity
108 	 * This is required since the MPIC HW doesn't limit
109 	 * several CPUs from acknowledging the same interrupt.
110 	 */
111 	if (count > 1)
112 		return -EINVAL;
113 
114 	for_each_cpu(cpu, cpu_online_mask)
115 		online_mask |= 1 << cpu_logical_map(cpu);
116 
117 	raw_spin_lock(&irq_controller_lock);
118 
119 	reg = readl(main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
120 	reg = (reg & (~online_mask)) | new_mask;
121 	writel(reg, main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
122 
123 	raw_spin_unlock(&irq_controller_lock);
124 
125 	return 0;
126 }
127 #endif
128 
129 static struct irq_chip armada_370_xp_irq_chip = {
130 	.name		= "armada_370_xp_irq",
131 	.irq_mask       = armada_370_xp_irq_mask,
132 	.irq_mask_ack   = armada_370_xp_irq_mask,
133 	.irq_unmask     = armada_370_xp_irq_unmask,
134 #ifdef CONFIG_SMP
135 	.irq_set_affinity = armada_xp_set_affinity,
136 #endif
137 };
138 
139 static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
140 				      unsigned int virq, irq_hw_number_t hw)
141 {
142 	armada_370_xp_irq_mask(irq_get_irq_data(virq));
143 	if (hw != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
144 		writel(hw, per_cpu_int_base +
145 			ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
146 	else
147 		writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
148 	irq_set_status_flags(virq, IRQ_LEVEL);
149 
150 	if (hw == ARMADA_370_XP_TIMER0_PER_CPU_IRQ) {
151 		irq_set_percpu_devid(virq);
152 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
153 					handle_percpu_devid_irq);
154 
155 	} else {
156 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
157 					handle_level_irq);
158 	}
159 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
160 
161 	return 0;
162 }
163 
164 #ifdef CONFIG_SMP
165 void armada_mpic_send_doorbell(const struct cpumask *mask, unsigned int irq)
166 {
167 	int cpu;
168 	unsigned long map = 0;
169 
170 	/* Convert our logical CPU mask into a physical one. */
171 	for_each_cpu(cpu, mask)
172 		map |= 1 << cpu_logical_map(cpu);
173 
174 	/*
175 	 * Ensure that stores to Normal memory are visible to the
176 	 * other CPUs before issuing the IPI.
177 	 */
178 	dsb();
179 
180 	/* submit softirq */
181 	writel((map << 8) | irq, main_int_base +
182 		ARMADA_370_XP_SW_TRIG_INT_OFFS);
183 }
184 
185 void armada_xp_mpic_smp_cpu_init(void)
186 {
187 	/* Clear pending IPIs */
188 	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
189 
190 	/* Enable first 8 IPIs */
191 	writel(IPI_DOORBELL_MASK, per_cpu_int_base +
192 		ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
193 
194 	/* Unmask IPI interrupt */
195 	writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
196 }
197 #endif /* CONFIG_SMP */
198 
199 static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
200 	.map = armada_370_xp_mpic_irq_map,
201 	.xlate = irq_domain_xlate_onecell,
202 };
203 
204 static asmlinkage void __exception_irq_entry
205 armada_370_xp_handle_irq(struct pt_regs *regs)
206 {
207 	u32 irqstat, irqnr;
208 
209 	do {
210 		irqstat = readl_relaxed(per_cpu_int_base +
211 					ARMADA_370_XP_CPU_INTACK_OFFS);
212 		irqnr = irqstat & 0x3FF;
213 
214 		if (irqnr > 1022)
215 			break;
216 
217 		if (irqnr > 0) {
218 			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
219 					irqnr);
220 			handle_IRQ(irqnr, regs);
221 			continue;
222 		}
223 #ifdef CONFIG_SMP
224 		/* IPI Handling */
225 		if (irqnr == 0) {
226 			u32 ipimask, ipinr;
227 
228 			ipimask = readl_relaxed(per_cpu_int_base +
229 						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
230 				& IPI_DOORBELL_MASK;
231 
232 			writel(~IPI_DOORBELL_MASK, per_cpu_int_base +
233 				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
234 
235 			/* Handle all pending doorbells */
236 			for (ipinr = IPI_DOORBELL_START;
237 			     ipinr < IPI_DOORBELL_END; ipinr++) {
238 				if (ipimask & (0x1 << ipinr))
239 					handle_IPI(ipinr, regs);
240 			}
241 			continue;
242 		}
243 #endif
244 
245 	} while (1);
246 }
247 
248 static int __init armada_370_xp_mpic_of_init(struct device_node *node,
249 					     struct device_node *parent)
250 {
251 	u32 control;
252 
253 	main_int_base = of_iomap(node, 0);
254 	per_cpu_int_base = of_iomap(node, 1);
255 
256 	BUG_ON(!main_int_base);
257 	BUG_ON(!per_cpu_int_base);
258 
259 	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
260 
261 	armada_370_xp_mpic_domain =
262 		irq_domain_add_linear(node, (control >> 2) & 0x3ff,
263 				&armada_370_xp_mpic_irq_ops, NULL);
264 
265 	if (!armada_370_xp_mpic_domain)
266 		panic("Unable to add Armada_370_Xp MPIC irq domain (DT)\n");
267 
268 	irq_set_default_host(armada_370_xp_mpic_domain);
269 
270 #ifdef CONFIG_SMP
271 	armada_xp_mpic_smp_cpu_init();
272 
273 	/*
274 	 * Set the default affinity from all CPUs to the boot cpu.
275 	 * This is required since the MPIC doesn't limit several CPUs
276 	 * from acknowledging the same interrupt.
277 	 */
278 	cpumask_clear(irq_default_affinity);
279 	cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
280 
281 #endif
282 
283 	set_handle_irq(armada_370_xp_handle_irq);
284 
285 	return 0;
286 }
287 
288 IRQCHIP_DECLARE(armada_370_xp_mpic, "marvell,mpic", armada_370_xp_mpic_of_init);
289