1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
3  */
4 
5 /*
6  * Driver for interrupt combiners in the Top-level Control and Status
7  * Registers (TCSR) hardware block in Qualcomm Technologies chips.
8  * An interrupt combiner in this block combines a set of interrupts by
9  * OR'ing the individual interrupt signals into a summary interrupt
10  * signal routed to a parent interrupt controller, and provides read-
11  * only, 32-bit registers to query the status of individual interrupts.
12  * The status bit for IRQ n is bit (n % 32) within register (n / 32)
13  * of the given combiner. Thus, each combiner can be described as a set
14  * of register offsets and the number of IRQs managed.
15  */
16 
17 #define pr_fmt(fmt) "QCOM80B1:" fmt
18 
19 #include <linux/acpi.h>
20 #include <linux/irqchip/chained_irq.h>
21 #include <linux/irqdomain.h>
22 #include <linux/platform_device.h>
23 
24 #define REG_SIZE 32
25 
26 struct combiner_reg {
27 	void __iomem *addr;
28 	unsigned long enabled;
29 };
30 
31 struct combiner {
32 	struct irq_domain   *domain;
33 	int                 parent_irq;
34 	u32                 nirqs;
35 	u32                 nregs;
36 	struct combiner_reg regs[0];
37 };
38 
39 static inline int irq_nr(u32 reg, u32 bit)
40 {
41 	return reg * REG_SIZE + bit;
42 }
43 
44 /*
45  * Handler for the cascaded IRQ.
46  */
47 static void combiner_handle_irq(struct irq_desc *desc)
48 {
49 	struct combiner *combiner = irq_desc_get_handler_data(desc);
50 	struct irq_chip *chip = irq_desc_get_chip(desc);
51 	u32 reg;
52 
53 	chained_irq_enter(chip, desc);
54 
55 	for (reg = 0; reg < combiner->nregs; reg++) {
56 		int virq;
57 		int hwirq;
58 		u32 bit;
59 		u32 status;
60 
61 		bit = readl_relaxed(combiner->regs[reg].addr);
62 		status = bit & combiner->regs[reg].enabled;
63 		if (bit && !status)
64 			pr_warn_ratelimited("Unexpected IRQ on CPU%d: (%08x %08lx %p)\n",
65 					    smp_processor_id(), bit,
66 					    combiner->regs[reg].enabled,
67 					    combiner->regs[reg].addr);
68 
69 		while (status) {
70 			bit = __ffs(status);
71 			status &= ~(1 << bit);
72 			hwirq = irq_nr(reg, bit);
73 			virq = irq_find_mapping(combiner->domain, hwirq);
74 			if (virq > 0)
75 				generic_handle_irq(virq);
76 
77 		}
78 	}
79 
80 	chained_irq_exit(chip, desc);
81 }
82 
83 static void combiner_irq_chip_mask_irq(struct irq_data *data)
84 {
85 	struct combiner *combiner = irq_data_get_irq_chip_data(data);
86 	struct combiner_reg *reg = combiner->regs + data->hwirq / REG_SIZE;
87 
88 	clear_bit(data->hwirq % REG_SIZE, &reg->enabled);
89 }
90 
91 static void combiner_irq_chip_unmask_irq(struct irq_data *data)
92 {
93 	struct combiner *combiner = irq_data_get_irq_chip_data(data);
94 	struct combiner_reg *reg = combiner->regs + data->hwirq / REG_SIZE;
95 
96 	set_bit(data->hwirq % REG_SIZE, &reg->enabled);
97 }
98 
99 static struct irq_chip irq_chip = {
100 	.irq_mask = combiner_irq_chip_mask_irq,
101 	.irq_unmask = combiner_irq_chip_unmask_irq,
102 	.name = "qcom-irq-combiner"
103 };
104 
105 static int combiner_irq_map(struct irq_domain *domain, unsigned int irq,
106 				   irq_hw_number_t hwirq)
107 {
108 	irq_set_chip_and_handler(irq, &irq_chip, handle_level_irq);
109 	irq_set_chip_data(irq, domain->host_data);
110 	irq_set_noprobe(irq);
111 	return 0;
112 }
113 
114 static void combiner_irq_unmap(struct irq_domain *domain, unsigned int irq)
115 {
116 	irq_domain_reset_irq_data(irq_get_irq_data(irq));
117 }
118 
119 static int combiner_irq_translate(struct irq_domain *d, struct irq_fwspec *fws,
120 				  unsigned long *hwirq, unsigned int *type)
121 {
122 	struct combiner *combiner = d->host_data;
123 
124 	if (is_acpi_node(fws->fwnode)) {
125 		if (WARN_ON((fws->param_count != 2) ||
126 			    (fws->param[0] >= combiner->nirqs) ||
127 			    (fws->param[1] & IORESOURCE_IRQ_LOWEDGE) ||
128 			    (fws->param[1] & IORESOURCE_IRQ_HIGHEDGE)))
129 			return -EINVAL;
130 
131 		*hwirq = fws->param[0];
132 		*type = fws->param[1];
133 		return 0;
134 	}
135 
136 	return -EINVAL;
137 }
138 
139 static const struct irq_domain_ops domain_ops = {
140 	.map = combiner_irq_map,
141 	.unmap = combiner_irq_unmap,
142 	.translate = combiner_irq_translate
143 };
144 
145 static acpi_status count_registers_cb(struct acpi_resource *ares, void *context)
146 {
147 	int *count = context;
148 
149 	if (ares->type == ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
150 		++(*count);
151 	return AE_OK;
152 }
153 
154 static int count_registers(struct platform_device *pdev)
155 {
156 	acpi_handle ahandle = ACPI_HANDLE(&pdev->dev);
157 	acpi_status status;
158 	int count = 0;
159 
160 	if (!acpi_has_method(ahandle, METHOD_NAME__CRS))
161 		return -EINVAL;
162 
163 	status = acpi_walk_resources(ahandle, METHOD_NAME__CRS,
164 				     count_registers_cb, &count);
165 	if (ACPI_FAILURE(status))
166 		return -EINVAL;
167 	return count;
168 }
169 
170 struct get_registers_context {
171 	struct device *dev;
172 	struct combiner *combiner;
173 	int err;
174 };
175 
176 static acpi_status get_registers_cb(struct acpi_resource *ares, void *context)
177 {
178 	struct get_registers_context *ctx = context;
179 	struct acpi_resource_generic_register *reg;
180 	phys_addr_t paddr;
181 	void __iomem *vaddr;
182 
183 	if (ares->type != ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
184 		return AE_OK;
185 
186 	reg = &ares->data.generic_reg;
187 	paddr = reg->address;
188 	if ((reg->space_id != ACPI_SPACE_MEM) ||
189 	    (reg->bit_offset != 0) ||
190 	    (reg->bit_width > REG_SIZE)) {
191 		dev_err(ctx->dev, "Bad register resource @%pa\n", &paddr);
192 		ctx->err = -EINVAL;
193 		return AE_ERROR;
194 	}
195 
196 	vaddr = devm_ioremap(ctx->dev, reg->address, REG_SIZE);
197 	if (!vaddr) {
198 		dev_err(ctx->dev, "Can't map register @%pa\n", &paddr);
199 		ctx->err = -ENOMEM;
200 		return AE_ERROR;
201 	}
202 
203 	ctx->combiner->regs[ctx->combiner->nregs].addr = vaddr;
204 	ctx->combiner->nirqs += reg->bit_width;
205 	ctx->combiner->nregs++;
206 	return AE_OK;
207 }
208 
209 static int get_registers(struct platform_device *pdev, struct combiner *comb)
210 {
211 	acpi_handle ahandle = ACPI_HANDLE(&pdev->dev);
212 	acpi_status status;
213 	struct get_registers_context ctx;
214 
215 	if (!acpi_has_method(ahandle, METHOD_NAME__CRS))
216 		return -EINVAL;
217 
218 	ctx.dev = &pdev->dev;
219 	ctx.combiner = comb;
220 	ctx.err = 0;
221 
222 	status = acpi_walk_resources(ahandle, METHOD_NAME__CRS,
223 				     get_registers_cb, &ctx);
224 	if (ACPI_FAILURE(status))
225 		return ctx.err;
226 	return 0;
227 }
228 
229 static int __init combiner_probe(struct platform_device *pdev)
230 {
231 	struct combiner *combiner;
232 	int nregs;
233 	int err;
234 
235 	nregs = count_registers(pdev);
236 	if (nregs <= 0) {
237 		dev_err(&pdev->dev, "Error reading register resources\n");
238 		return -EINVAL;
239 	}
240 
241 	combiner = devm_kzalloc(&pdev->dev, struct_size(combiner, regs, nregs),
242 				GFP_KERNEL);
243 	if (!combiner)
244 		return -ENOMEM;
245 
246 	err = get_registers(pdev, combiner);
247 	if (err < 0)
248 		return err;
249 
250 	combiner->parent_irq = platform_get_irq(pdev, 0);
251 	if (combiner->parent_irq <= 0) {
252 		dev_err(&pdev->dev, "Error getting IRQ resource\n");
253 		return -EPROBE_DEFER;
254 	}
255 
256 	combiner->domain = irq_domain_create_linear(pdev->dev.fwnode, combiner->nirqs,
257 						    &domain_ops, combiner);
258 	if (!combiner->domain)
259 		/* Errors printed by irq_domain_create_linear */
260 		return -ENODEV;
261 
262 	irq_set_chained_handler_and_data(combiner->parent_irq,
263 					 combiner_handle_irq, combiner);
264 
265 	dev_info(&pdev->dev, "Initialized with [p=%d,n=%d,r=%p]\n",
266 		 combiner->parent_irq, combiner->nirqs, combiner->regs[0].addr);
267 	return 0;
268 }
269 
270 static const struct acpi_device_id qcom_irq_combiner_ids[] = {
271 	{ "QCOM80B1", },
272 	{ }
273 };
274 
275 static struct platform_driver qcom_irq_combiner_probe = {
276 	.driver = {
277 		.name = "qcom-irq-combiner",
278 		.acpi_match_table = ACPI_PTR(qcom_irq_combiner_ids),
279 	},
280 	.probe = combiner_probe,
281 };
282 builtin_platform_driver(qcom_irq_combiner_probe);
283