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>
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>
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
;
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
)
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
);
62 while (events
& mask
) {
63 hwirq
= fls64(events
) - 1;
64 if (BIT_ULL(hwirq
) & mask
) {
65 virq
= irq_find_mapping(opal_event_irqchip
.domain
,
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
)
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
)
114 static struct opal_event_irqchip opal_event_irqchip
= {
117 .irq_mask
= opal_event_mask
,
118 .irq_unmask
= opal_event_unmask
,
119 .irq_set_type
= opal_event_set_type
,
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
,
134 static irqreturn_t
opal_interrupt(int irq
, void *data
)
138 opal_handle_interrupt(virq_to_hw(irq
), &events
);
139 opal_handle_events(be64_to_cpu(events
));
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
;
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)
175 /* First free interrupts, which will also mask them */
176 for (i
= 0; i
< opal_irq_count
; i
++) {
178 free_irq(opal_irqs
[i
], NULL
);
183 int __init
opal_event_init(void)
185 struct device_node
*dn
, *opal_node
;
187 int i
, irqlen
, rc
= 0;
189 opal_node
= of_find_node_by_path("/ibm,opal");
191 pr_warn("opal: Node not found\n");
195 /* If dn is NULL it means the domain won't be linked to a DT
196 * node so therefore irq_of_parse_and_map(...) wont work. But
197 * that shouldn't be problem because if we're running a
198 * version of skiboot that doesn't have the dn then the
199 * devices won't have the correct properties and will have to
200 * fall back to the legacy method (opal_event_request(...))
202 dn
= of_find_compatible_node(NULL
, NULL
, "ibm,opal-event");
203 opal_event_irqchip
.domain
= irq_domain_add_linear(dn
, MAX_NUM_EVENTS
,
204 &opal_event_domain_ops
, &opal_event_irqchip
);
206 if (!opal_event_irqchip
.domain
) {
207 pr_warn("opal: Unable to create irq domain\n");
212 /* Get interrupt property */
213 irqs
= of_get_property(opal_node
, "opal-interrupts", &irqlen
);
214 opal_irq_count
= irqs
? (irqlen
/ 4) : 0;
215 pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count
);
217 /* Install interrupt handlers */
218 opal_irqs
= kcalloc(opal_irq_count
, sizeof(*opal_irqs
), GFP_KERNEL
);
219 for (i
= 0; irqs
&& i
< opal_irq_count
; i
++, irqs
++) {
220 unsigned int irq
, virq
;
222 /* Get hardware and virtual IRQ */
223 irq
= be32_to_cpup(irqs
);
224 virq
= irq_create_mapping(NULL
, irq
);
226 pr_warn("Failed to map irq 0x%x\n", irq
);
230 /* Install interrupt handler */
231 rc
= request_irq(virq
, opal_interrupt
, IRQF_TRIGGER_LOW
,
234 irq_dispose_mapping(virq
);
235 pr_warn("Error %d requesting irq %d (0x%x)\n",
245 of_node_put(opal_node
);
248 machine_arch_initcall(powernv
, opal_event_init
);
251 * opal_event_request(unsigned int opal_event_nr) - Request an event
252 * @opal_event_nr: the opal event number to request
254 * This routine can be used to find the linux virq number which can
255 * then be passed to request_irq to assign a handler for a particular
256 * opal event. This should only be used by legacy devices which don't
257 * have proper device tree bindings. Most devices should use
258 * irq_of_parse_and_map() instead.
260 int opal_event_request(unsigned int opal_event_nr
)
262 if (WARN_ON_ONCE(!opal_event_irqchip
.domain
))
265 return irq_create_mapping(opal_event_irqchip
.domain
, opal_event_nr
);
267 EXPORT_SYMBOL(opal_event_request
);