1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Generic Broadcom Set Top Box Level 2 Interrupt controller driver
4  *
5  * Copyright (C) 2014-2017 Broadcom
6  */
7 
8 #define pr_fmt(fmt)	KBUILD_MODNAME	": " fmt
9 
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/spinlock.h>
15 #include <linux/of.h>
16 #include <linux/of_irq.h>
17 #include <linux/of_address.h>
18 #include <linux/of_platform.h>
19 #include <linux/interrupt.h>
20 #include <linux/irq.h>
21 #include <linux/io.h>
22 #include <linux/irqdomain.h>
23 #include <linux/irqchip.h>
24 #include <linux/irqchip/chained_irq.h>
25 
26 struct brcmstb_intc_init_params {
27 	irq_flow_handler_t handler;
28 	int cpu_status;
29 	int cpu_clear;
30 	int cpu_mask_status;
31 	int cpu_mask_set;
32 	int cpu_mask_clear;
33 };
34 
35 /* Register offsets in the L2 latched interrupt controller */
36 static const struct brcmstb_intc_init_params l2_edge_intc_init = {
37 	.handler		= handle_edge_irq,
38 	.cpu_status		= 0x00,
39 	.cpu_clear		= 0x08,
40 	.cpu_mask_status	= 0x0c,
41 	.cpu_mask_set		= 0x10,
42 	.cpu_mask_clear		= 0x14
43 };
44 
45 /* Register offsets in the L2 level interrupt controller */
46 static const struct brcmstb_intc_init_params l2_lvl_intc_init = {
47 	.handler		= handle_level_irq,
48 	.cpu_status		= 0x00,
49 	.cpu_clear		= -1, /* Register not present */
50 	.cpu_mask_status	= 0x04,
51 	.cpu_mask_set		= 0x08,
52 	.cpu_mask_clear		= 0x0C
53 };
54 
55 /* L2 intc private data structure */
56 struct brcmstb_l2_intc_data {
57 	struct irq_domain *domain;
58 	struct irq_chip_generic *gc;
59 	int status_offset;
60 	int mask_offset;
61 	bool can_wake;
62 	u32 saved_mask; /* for suspend/resume */
63 };
64 
65 /**
66  * brcmstb_l2_mask_and_ack - Mask and ack pending interrupt
67  * @d: irq_data
68  *
69  * Chip has separate enable/disable registers instead of a single mask
70  * register and pending interrupt is acknowledged by setting a bit.
71  *
72  * Note: This function is generic and could easily be added to the
73  * generic irqchip implementation if there ever becomes a will to do so.
74  * Perhaps with a name like irq_gc_mask_disable_and_ack_set().
75  *
76  * e.g.: https://patchwork.kernel.org/patch/9831047/
77  */
78 static void brcmstb_l2_mask_and_ack(struct irq_data *d)
79 {
80 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
81 	struct irq_chip_type *ct = irq_data_get_chip_type(d);
82 	u32 mask = d->mask;
83 
84 	irq_gc_lock(gc);
85 	irq_reg_writel(gc, mask, ct->regs.disable);
86 	*ct->mask_cache &= ~mask;
87 	irq_reg_writel(gc, mask, ct->regs.ack);
88 	irq_gc_unlock(gc);
89 }
90 
91 static void brcmstb_l2_intc_irq_handle(struct irq_desc *desc)
92 {
93 	struct brcmstb_l2_intc_data *b = irq_desc_get_handler_data(desc);
94 	struct irq_chip *chip = irq_desc_get_chip(desc);
95 	unsigned int irq;
96 	u32 status;
97 
98 	chained_irq_enter(chip, desc);
99 
100 	status = irq_reg_readl(b->gc, b->status_offset) &
101 		~(irq_reg_readl(b->gc, b->mask_offset));
102 
103 	if (status == 0) {
104 		raw_spin_lock(&desc->lock);
105 		handle_bad_irq(desc);
106 		raw_spin_unlock(&desc->lock);
107 		goto out;
108 	}
109 
110 	do {
111 		irq = ffs(status) - 1;
112 		status &= ~(1 << irq);
113 		generic_handle_irq(irq_linear_revmap(b->domain, irq));
114 	} while (status);
115 out:
116 	chained_irq_exit(chip, desc);
117 }
118 
119 static void brcmstb_l2_intc_suspend(struct irq_data *d)
120 {
121 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
122 	struct irq_chip_type *ct = irq_data_get_chip_type(d);
123 	struct brcmstb_l2_intc_data *b = gc->private;
124 	unsigned long flags;
125 
126 	irq_gc_lock_irqsave(gc, flags);
127 	/* Save the current mask */
128 	b->saved_mask = irq_reg_readl(gc, ct->regs.mask);
129 
130 	if (b->can_wake) {
131 		/* Program the wakeup mask */
132 		irq_reg_writel(gc, ~gc->wake_active, ct->regs.disable);
133 		irq_reg_writel(gc, gc->wake_active, ct->regs.enable);
134 	}
135 	irq_gc_unlock_irqrestore(gc, flags);
136 }
137 
138 static void brcmstb_l2_intc_resume(struct irq_data *d)
139 {
140 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
141 	struct irq_chip_type *ct = irq_data_get_chip_type(d);
142 	struct brcmstb_l2_intc_data *b = gc->private;
143 	unsigned long flags;
144 
145 	irq_gc_lock_irqsave(gc, flags);
146 	if (ct->chip.irq_ack) {
147 		/* Clear unmasked non-wakeup interrupts */
148 		irq_reg_writel(gc, ~b->saved_mask & ~gc->wake_active,
149 				ct->regs.ack);
150 	}
151 
152 	/* Restore the saved mask */
153 	irq_reg_writel(gc, b->saved_mask, ct->regs.disable);
154 	irq_reg_writel(gc, ~b->saved_mask, ct->regs.enable);
155 	irq_gc_unlock_irqrestore(gc, flags);
156 }
157 
158 static int __init brcmstb_l2_intc_of_init(struct device_node *np,
159 					  struct device_node *parent,
160 					  const struct brcmstb_intc_init_params
161 					  *init_params)
162 {
163 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
164 	struct brcmstb_l2_intc_data *data;
165 	struct irq_chip_type *ct;
166 	int ret;
167 	unsigned int flags;
168 	int parent_irq;
169 	void __iomem *base;
170 
171 	data = kzalloc(sizeof(*data), GFP_KERNEL);
172 	if (!data)
173 		return -ENOMEM;
174 
175 	base = of_iomap(np, 0);
176 	if (!base) {
177 		pr_err("failed to remap intc L2 registers\n");
178 		ret = -ENOMEM;
179 		goto out_free;
180 	}
181 
182 	/* Disable all interrupts by default */
183 	writel(0xffffffff, base + init_params->cpu_mask_set);
184 
185 	/* Wakeup interrupts may be retained from S5 (cold boot) */
186 	data->can_wake = of_property_read_bool(np, "brcm,irq-can-wake");
187 	if (!data->can_wake && (init_params->cpu_clear >= 0))
188 		writel(0xffffffff, base + init_params->cpu_clear);
189 
190 	parent_irq = irq_of_parse_and_map(np, 0);
191 	if (!parent_irq) {
192 		pr_err("failed to find parent interrupt\n");
193 		ret = -EINVAL;
194 		goto out_unmap;
195 	}
196 
197 	data->domain = irq_domain_add_linear(np, 32,
198 				&irq_generic_chip_ops, NULL);
199 	if (!data->domain) {
200 		ret = -ENOMEM;
201 		goto out_unmap;
202 	}
203 
204 	/* MIPS chips strapped for BE will automagically configure the
205 	 * peripheral registers for CPU-native byte order.
206 	 */
207 	flags = 0;
208 	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
209 		flags |= IRQ_GC_BE_IO;
210 
211 	/* Allocate a single Generic IRQ chip for this node */
212 	ret = irq_alloc_domain_generic_chips(data->domain, 32, 1,
213 			np->full_name, init_params->handler, clr, 0, flags);
214 	if (ret) {
215 		pr_err("failed to allocate generic irq chip\n");
216 		goto out_free_domain;
217 	}
218 
219 	/* Set the IRQ chaining logic */
220 	irq_set_chained_handler_and_data(parent_irq,
221 					 brcmstb_l2_intc_irq_handle, data);
222 
223 	data->gc = irq_get_domain_generic_chip(data->domain, 0);
224 	data->gc->reg_base = base;
225 	data->gc->private = data;
226 	data->status_offset = init_params->cpu_status;
227 	data->mask_offset = init_params->cpu_mask_status;
228 
229 	ct = data->gc->chip_types;
230 
231 	if (init_params->cpu_clear >= 0) {
232 		ct->regs.ack = init_params->cpu_clear;
233 		ct->chip.irq_ack = irq_gc_ack_set_bit;
234 		ct->chip.irq_mask_ack = brcmstb_l2_mask_and_ack;
235 	} else {
236 		/* No Ack - but still slightly more efficient to define this */
237 		ct->chip.irq_mask_ack = irq_gc_mask_disable_reg;
238 	}
239 
240 	ct->chip.irq_mask = irq_gc_mask_disable_reg;
241 	ct->regs.disable = init_params->cpu_mask_set;
242 	ct->regs.mask = init_params->cpu_mask_status;
243 
244 	ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
245 	ct->regs.enable = init_params->cpu_mask_clear;
246 
247 	ct->chip.irq_suspend = brcmstb_l2_intc_suspend;
248 	ct->chip.irq_resume = brcmstb_l2_intc_resume;
249 	ct->chip.irq_pm_shutdown = brcmstb_l2_intc_suspend;
250 
251 	if (data->can_wake) {
252 		/* This IRQ chip can wake the system, set all child interrupts
253 		 * in wake_enabled mask
254 		 */
255 		data->gc->wake_enabled = 0xffffffff;
256 		ct->chip.irq_set_wake = irq_gc_set_wake;
257 	}
258 
259 	pr_info("registered L2 intc (%pOF, parent irq: %d)\n", np, parent_irq);
260 
261 	return 0;
262 
263 out_free_domain:
264 	irq_domain_remove(data->domain);
265 out_unmap:
266 	iounmap(base);
267 out_free:
268 	kfree(data);
269 	return ret;
270 }
271 
272 static int __init brcmstb_l2_edge_intc_of_init(struct device_node *np,
273 	struct device_node *parent)
274 {
275 	return brcmstb_l2_intc_of_init(np, parent, &l2_edge_intc_init);
276 }
277 IRQCHIP_DECLARE(brcmstb_l2_intc, "brcm,l2-intc", brcmstb_l2_edge_intc_of_init);
278 
279 static int __init brcmstb_l2_lvl_intc_of_init(struct device_node *np,
280 	struct device_node *parent)
281 {
282 	return brcmstb_l2_intc_of_init(np, parent, &l2_lvl_intc_init);
283 }
284 IRQCHIP_DECLARE(bcm7271_l2_intc, "brcm,bcm7271-l2-intc",
285 	brcmstb_l2_lvl_intc_of_init);
286