Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / arch / powerpc / platforms / powernv / opal-irqchip.c
blob9d1b8c0aaf93bb027474bc648ebc41219f244204
1 /*
2 * This file implements an irqchip for OPAL events. Whenever there is
3 * an interrupt that is handled by OPAL we get passed a list of events
4 * that Linux needs to do something about. These basically look like
5 * interrupts to Linux so we implement an irqchip to handle them.
7 * Copyright Alistair Popple, IBM Corporation 2014.
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
14 #include <linux/bitops.h>
15 #include <linux/irq.h>
16 #include <linux/irqchip.h>
17 #include <linux/irqdomain.h>
18 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/kthread.h>
23 #include <linux/delay.h>
24 #include <linux/slab.h>
25 #include <linux/irq_work.h>
27 #include <asm/machdep.h>
28 #include <asm/opal.h>
30 #include "powernv.h"
32 /* Maximum number of events supported by OPAL firmware */
33 #define MAX_NUM_EVENTS 64
35 struct opal_event_irqchip {
36 struct irq_chip irqchip;
37 struct irq_domain *domain;
38 unsigned long mask;
40 static struct opal_event_irqchip opal_event_irqchip;
42 static unsigned int opal_irq_count;
43 static unsigned int *opal_irqs;
45 static void opal_handle_irq_work(struct irq_work *work);
46 static u64 last_outstanding_events;
47 static struct irq_work opal_event_irq_work = {
48 .func = opal_handle_irq_work,
51 void opal_handle_events(uint64_t events)
53 int virq, hwirq = 0;
54 u64 mask = opal_event_irqchip.mask;
56 if (!in_irq() && (events & mask)) {
57 last_outstanding_events = events;
58 irq_work_queue(&opal_event_irq_work);
59 return;
62 while (events & mask) {
63 hwirq = fls64(events) - 1;
64 if (BIT_ULL(hwirq) & mask) {
65 virq = irq_find_mapping(opal_event_irqchip.domain,
66 hwirq);
67 if (virq)
68 generic_handle_irq(virq);
70 events &= ~BIT_ULL(hwirq);
74 static void opal_event_mask(struct irq_data *d)
76 clear_bit(d->hwirq, &opal_event_irqchip.mask);
79 static void opal_event_unmask(struct irq_data *d)
81 __be64 events;
83 set_bit(d->hwirq, &opal_event_irqchip.mask);
85 opal_poll_events(&events);
86 last_outstanding_events = be64_to_cpu(events);
89 * We can't just handle the events now with opal_handle_events().
90 * If we did we would deadlock when opal_event_unmask() is called from
91 * handle_level_irq() with the irq descriptor lock held, because
92 * calling opal_handle_events() would call generic_handle_irq() and
93 * then handle_level_irq() which would try to take the descriptor lock
94 * again. Instead queue the events for later.
96 if (last_outstanding_events & opal_event_irqchip.mask)
97 /* Need to retrigger the interrupt */
98 irq_work_queue(&opal_event_irq_work);
101 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
104 * For now we only support level triggered events. The irq
105 * handler will be called continuously until the event has
106 * been cleared in OPAL.
108 if (flow_type != IRQ_TYPE_LEVEL_HIGH)
109 return -EINVAL;
111 return 0;
114 static struct opal_event_irqchip opal_event_irqchip = {
115 .irqchip = {
116 .name = "OPAL EVT",
117 .irq_mask = opal_event_mask,
118 .irq_unmask = opal_event_unmask,
119 .irq_set_type = opal_event_set_type,
121 .mask = 0,
124 static int opal_event_map(struct irq_domain *d, unsigned int irq,
125 irq_hw_number_t hwirq)
127 irq_set_chip_data(irq, &opal_event_irqchip);
128 irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
129 handle_level_irq);
131 return 0;
134 static irqreturn_t opal_interrupt(int irq, void *data)
136 __be64 events;
138 opal_handle_interrupt(virq_to_hw(irq), &events);
139 opal_handle_events(be64_to_cpu(events));
141 return IRQ_HANDLED;
144 static void opal_handle_irq_work(struct irq_work *work)
146 opal_handle_events(last_outstanding_events);
149 static int opal_event_match(struct irq_domain *h, struct device_node *node,
150 enum irq_domain_bus_token bus_token)
152 return irq_domain_get_of_node(h) == node;
155 static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
156 const u32 *intspec, unsigned int intsize,
157 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
159 *out_hwirq = intspec[0];
160 *out_flags = IRQ_TYPE_LEVEL_HIGH;
162 return 0;
165 static const struct irq_domain_ops opal_event_domain_ops = {
166 .match = opal_event_match,
167 .map = opal_event_map,
168 .xlate = opal_event_xlate,
171 void opal_event_shutdown(void)
173 unsigned int i;
175 /* First free interrupts, which will also mask them */
176 for (i = 0; i < opal_irq_count; i++) {
177 if (!opal_irqs[i])
178 continue;
180 if (in_interrupt())
181 disable_irq_nosync(opal_irqs[i]);
182 else
183 free_irq(opal_irqs[i], NULL);
185 opal_irqs[i] = 0;
189 int __init opal_event_init(void)
191 struct device_node *dn, *opal_node;
192 const char **names;
193 u32 *irqs;
194 int i, rc;
196 opal_node = of_find_node_by_path("/ibm,opal");
197 if (!opal_node) {
198 pr_warn("opal: Node not found\n");
199 return -ENODEV;
202 /* If dn is NULL it means the domain won't be linked to a DT
203 * node so therefore irq_of_parse_and_map(...) wont work. But
204 * that shouldn't be problem because if we're running a
205 * version of skiboot that doesn't have the dn then the
206 * devices won't have the correct properties and will have to
207 * fall back to the legacy method (opal_event_request(...))
208 * anyway. */
209 dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
210 opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
211 &opal_event_domain_ops, &opal_event_irqchip);
212 of_node_put(dn);
213 if (!opal_event_irqchip.domain) {
214 pr_warn("opal: Unable to create irq domain\n");
215 rc = -ENOMEM;
216 goto out;
219 /* Get opal-interrupts property and names if present */
220 rc = of_property_count_u32_elems(opal_node, "opal-interrupts");
221 if (rc < 0)
222 goto out;
224 opal_irq_count = rc;
225 pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);
227 irqs = kcalloc(opal_irq_count, sizeof(*irqs), GFP_KERNEL);
228 names = kcalloc(opal_irq_count, sizeof(*names), GFP_KERNEL);
229 opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
231 if (WARN_ON(!irqs || !names || !opal_irqs))
232 goto out_free;
234 rc = of_property_read_u32_array(opal_node, "opal-interrupts",
235 irqs, opal_irq_count);
236 if (rc < 0) {
237 pr_err("Error %d reading opal-interrupts array\n", rc);
238 goto out_free;
241 /* It's not an error for the names to be missing */
242 of_property_read_string_array(opal_node, "opal-interrupts-names",
243 names, opal_irq_count);
245 /* Install interrupt handlers */
246 for (i = 0; i < opal_irq_count; i++) {
247 unsigned int virq;
248 char *name;
250 /* Get hardware and virtual IRQ */
251 virq = irq_create_mapping(NULL, irqs[i]);
252 if (!virq) {
253 pr_warn("Failed to map irq 0x%x\n", irqs[i]);
254 continue;
257 if (names[i] && strlen(names[i]))
258 name = kasprintf(GFP_KERNEL, "opal-%s", names[i]);
259 else
260 name = kasprintf(GFP_KERNEL, "opal");
262 /* Install interrupt handler */
263 rc = request_irq(virq, opal_interrupt, IRQF_TRIGGER_LOW,
264 name, NULL);
265 if (rc) {
266 irq_dispose_mapping(virq);
267 pr_warn("Error %d requesting irq %d (0x%x)\n",
268 rc, virq, irqs[i]);
269 continue;
272 /* Cache IRQ */
273 opal_irqs[i] = virq;
276 out_free:
277 kfree(irqs);
278 kfree(names);
279 out:
280 of_node_put(opal_node);
281 return rc;
283 machine_arch_initcall(powernv, opal_event_init);
286 * opal_event_request(unsigned int opal_event_nr) - Request an event
287 * @opal_event_nr: the opal event number to request
289 * This routine can be used to find the linux virq number which can
290 * then be passed to request_irq to assign a handler for a particular
291 * opal event. This should only be used by legacy devices which don't
292 * have proper device tree bindings. Most devices should use
293 * irq_of_parse_and_map() instead.
295 int opal_event_request(unsigned int opal_event_nr)
297 if (WARN_ON_ONCE(!opal_event_irqchip.domain))
298 return 0;
300 return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
302 EXPORT_SYMBOL(opal_event_request);