1/*
  2 * ACPI GSI IRQ layer
  3 *
  4 * Copyright (C) 2015 ARM Ltd.
  5 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11#include <linux/acpi.h>
 12#include <linux/irq.h>
 13#include <linux/irqdomain.h>
 14#include <linux/of.h>
 15
 16enum acpi_irq_model_id acpi_irq_model;
 17
 18static struct fwnode_handle *acpi_gsi_domain_id;
 19
 20/**
 21 * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
 22 * @gsi: GSI IRQ number to map
 23 * @irq: pointer where linux IRQ number is stored
 24 *
 25 * irq location updated with irq value [>0 on success, 0 on failure]
 26 *
 27 * Returns: 0 on success
 28 *          -EINVAL on failure
 29 */
 30int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 31{
 32	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
 33							DOMAIN_BUS_ANY);
 34
 35	*irq = irq_find_mapping(d, gsi);
 36	/*
 37	 * *irq == 0 means no mapping, that should
 38	 * be reported as a failure
 39	 */
 40	return (*irq > 0) ? 0 : -EINVAL;
 41}
 42EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
 43
 44/**
 45 * acpi_register_gsi() - Map a GSI to a linux IRQ number
 46 * @dev: device for which IRQ has to be mapped
 47 * @gsi: GSI IRQ number
 48 * @trigger: trigger type of the GSI number to be mapped
 49 * @polarity: polarity of the GSI to be mapped
 50 *
 51 * Returns: a valid linux IRQ number on success
 52 *          -EINVAL on failure
 53 */
 54int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 55		      int polarity)
 56{
 57	struct irq_fwspec fwspec;
 58
 59	if (WARN_ON(!acpi_gsi_domain_id)) {
 60		pr_warn("GSI: No registered irqchip, giving up\n");
 61		return -EINVAL;
 62	}
 63
 64	fwspec.fwnode = acpi_gsi_domain_id;
 65	fwspec.param[0] = gsi;
 66	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
 67	fwspec.param_count = 2;
 68
 69	return irq_create_fwspec_mapping(&fwspec);
 70}
 71EXPORT_SYMBOL_GPL(acpi_register_gsi);
 72
 73/**
 74 * acpi_unregister_gsi() - Free a GSI<->linux IRQ number mapping
 75 * @gsi: GSI IRQ number
 76 */
 77void acpi_unregister_gsi(u32 gsi)
 78{
 79	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
 80							DOMAIN_BUS_ANY);
 81	int irq = irq_find_mapping(d, gsi);
 82
 83	irq_dispose_mapping(irq);
 84}
 85EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
 86
 87/**
 88 * acpi_get_irq_source_fwhandle() - Retrieve fwhandle from IRQ resource source.
 89 * @source: acpi_resource_source to use for the lookup.
 90 *
 91 * Description:
 92 * Retrieve the fwhandle of the device referenced by the given IRQ resource
 93 * source.
 94 *
 95 * Return:
 96 * The referenced device fwhandle or NULL on failure
 97 */
 98static struct fwnode_handle *
 99acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source)
100{
101	struct fwnode_handle *result;
102	struct acpi_device *device;
103	acpi_handle handle;
104	acpi_status status;
105
106	if (!source->string_length)
107		return acpi_gsi_domain_id;
108
109	status = acpi_get_handle(NULL, source->string_ptr, &handle);
110	if (WARN_ON(ACPI_FAILURE(status)))
111		return NULL;
112
113	device = acpi_bus_get_acpi_device(handle);
114	if (WARN_ON(!device))
115		return NULL;
116
117	result = &device->fwnode;
118	acpi_bus_put_acpi_device(device);
119	return result;
120}
121
122/*
123 * Context for the resource walk used to lookup IRQ resources.
124 * Contains a return code, the lookup index, and references to the flags
125 * and fwspec where the result is returned.
126 */
127struct acpi_irq_parse_one_ctx {
128	int rc;
129	unsigned int index;
130	unsigned long *res_flags;
131	struct irq_fwspec *fwspec;
132};
133
134/**
135 * acpi_irq_parse_one_match - Handle a matching IRQ resource.
136 * @fwnode: matching fwnode
137 * @hwirq: hardware IRQ number
138 * @triggering: triggering attributes of hwirq
139 * @polarity: polarity attributes of hwirq
140 * @polarity: polarity attributes of hwirq
141 * @shareable: shareable attributes of hwirq
142 * @ctx: acpi_irq_parse_one_ctx updated by this function
143 *
144 * Description:
145 * Handle a matching IRQ resource by populating the given ctx with
146 * the information passed.
147 */
148static inline void acpi_irq_parse_one_match(struct fwnode_handle *fwnode,
149					    u32 hwirq, u8 triggering,
150					    u8 polarity, u8 shareable,
151					    struct acpi_irq_parse_one_ctx *ctx)
152{
153	if (!fwnode)
154		return;
155	ctx->rc = 0;
156	*ctx->res_flags = acpi_dev_irq_flags(triggering, polarity, shareable);
157	ctx->fwspec->fwnode = fwnode;
158	ctx->fwspec->param[0] = hwirq;
159	ctx->fwspec->param[1] = acpi_dev_get_irq_type(triggering, polarity);
160	ctx->fwspec->param_count = 2;
161}
162
163/**
164 * acpi_irq_parse_one_cb - Handle the given resource.
165 * @ares: resource to handle
166 * @context: context for the walk
167 *
168 * Description:
169 * This is called by acpi_walk_resources passing each resource returned by
170 * the _CRS method. We only inspect IRQ resources. Since IRQ resources
171 * might contain multiple interrupts we check if the index is within this
172 * one's interrupt array, otherwise we subtract the current resource IRQ
173 * count from the lookup index to prepare for the next resource.
174 * Once a match is found we call acpi_irq_parse_one_match to populate
175 * the result and end the walk by returning AE_CTRL_TERMINATE.
176 *
177 * Return:
178 * AE_OK if the walk should continue, AE_CTRL_TERMINATE if a matching
179 * IRQ resource was found.
180 */
181static acpi_status acpi_irq_parse_one_cb(struct acpi_resource *ares,
182					 void *context)
183{
184	struct acpi_irq_parse_one_ctx *ctx = context;
185	struct acpi_resource_irq *irq;
186	struct acpi_resource_extended_irq *eirq;
187	struct fwnode_handle *fwnode;
188
189	switch (ares->type) {
190	case ACPI_RESOURCE_TYPE_IRQ:
191		irq = &ares->data.irq;
192		if (ctx->index >= irq->interrupt_count) {
193			ctx->index -= irq->interrupt_count;
194			return AE_OK;
195		}
196		fwnode = acpi_gsi_domain_id;
197		acpi_irq_parse_one_match(fwnode, irq->interrupts[ctx->index],
198					 irq->triggering, irq->polarity,
199					 irq->sharable, ctx);
200		return AE_CTRL_TERMINATE;
201	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
202		eirq = &ares->data.extended_irq;
203		if (eirq->producer_consumer == ACPI_PRODUCER)
204			return AE_OK;
205		if (ctx->index >= eirq->interrupt_count) {
206			ctx->index -= eirq->interrupt_count;
207			return AE_OK;
208		}
209		fwnode = acpi_get_irq_source_fwhandle(&eirq->resource_source);
210		acpi_irq_parse_one_match(fwnode, eirq->interrupts[ctx->index],
211					 eirq->triggering, eirq->polarity,
212					 eirq->sharable, ctx);
213		return AE_CTRL_TERMINATE;
214	}
215
216	return AE_OK;
217}
218
219/**
220 * acpi_irq_parse_one - Resolve an interrupt for a device
221 * @handle: the device whose interrupt is to be resolved
222 * @index: index of the interrupt to resolve
223 * @fwspec: structure irq_fwspec filled by this function
224 * @flags: resource flags filled by this function
225 *
226 * Description:
227 * Resolves an interrupt for a device by walking its CRS resources to find
228 * the appropriate ACPI IRQ resource and populating the given struct irq_fwspec
229 * and flags.
230 *
231 * Return:
232 * The result stored in ctx.rc by the callback, or the default -EINVAL value
233 * if an error occurs.
234 */
235static int acpi_irq_parse_one(acpi_handle handle, unsigned int index,
236			      struct irq_fwspec *fwspec, unsigned long *flags)
237{
238	struct acpi_irq_parse_one_ctx ctx = { -EINVAL, index, flags, fwspec };
239
240	acpi_walk_resources(handle, METHOD_NAME__CRS, acpi_irq_parse_one_cb, &ctx);
241	return ctx.rc;
242}
243
244/**
245 * acpi_irq_get - Lookup an ACPI IRQ resource and use it to initialize resource.
246 * @handle: ACPI device handle
247 * @index:  ACPI IRQ resource index to lookup
248 * @res:    Linux IRQ resource to initialize
249 *
250 * Description:
251 * Look for the ACPI IRQ resource with the given index and use it to initialize
252 * the given Linux IRQ resource.
253 *
254 * Return:
255 * 0 on success
256 * -EINVAL if an error occurs
257 * -EPROBE_DEFER if the IRQ lookup/conversion failed
258 */
259int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
260{
261	struct irq_fwspec fwspec;
262	struct irq_domain *domain;
263	unsigned long flags;
264	int rc;
265
266	rc = acpi_irq_parse_one(handle, index, &fwspec, &flags);
267	if (rc)
268		return rc;
269
270	domain = irq_find_matching_fwnode(fwspec.fwnode, DOMAIN_BUS_ANY);
271	if (!domain)
272		return -EPROBE_DEFER;
273
274	rc = irq_create_fwspec_mapping(&fwspec);
275	if (rc <= 0)
276		return -EINVAL;
277
278	res->start = rc;
279	res->end = rc;
280	res->flags = flags;
281
282	return 0;
283}
284EXPORT_SYMBOL_GPL(acpi_irq_get);
285
286/**
287 * acpi_set_irq_model - Setup the GSI irqdomain information
288 * @model: the value assigned to acpi_irq_model
289 * @fwnode: the irq_domain identifier for mapping and looking up
290 *          GSI interrupts
291 */
292void __init acpi_set_irq_model(enum acpi_irq_model_id model,
293			       struct fwnode_handle *fwnode)
294{
295	acpi_irq_model = model;
296	acpi_gsi_domain_id = fwnode;
297}