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. 6 * 7 * Copyright Alistair Popple, IBM Corporation 2014. 8 * 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. 13 */ 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/of_irq.h> 26 27 #include <asm/machdep.h> 28 #include <asm/opal.h> 29 30 #include "powernv.h" 31 32 /* Maximum number of events supported by OPAL firmware */ 33 #define MAX_NUM_EVENTS 64 34 35 struct opal_event_irqchip { 36 struct irq_chip irqchip; 37 struct irq_domain *domain; 38 unsigned long mask; 39 }; 40 static struct opal_event_irqchip opal_event_irqchip; 41 static u64 last_outstanding_events; 42 static int opal_irq_count; 43 static struct resource *opal_irqs; 44 45 void opal_handle_events(void) 46 { 47 __be64 events = 0; 48 u64 e; 49 50 e = READ_ONCE(last_outstanding_events) & opal_event_irqchip.mask; 51 again: 52 while (e) { 53 int virq, hwirq; 54 55 hwirq = fls64(e) - 1; 56 e &= ~BIT_ULL(hwirq); 57 58 local_irq_disable(); 59 virq = irq_find_mapping(opal_event_irqchip.domain, hwirq); 60 if (virq) { 61 irq_enter(); 62 generic_handle_irq(virq); 63 irq_exit(); 64 } 65 local_irq_enable(); 66 67 cond_resched(); 68 } 69 last_outstanding_events = 0; 70 if (opal_poll_events(&events) != OPAL_SUCCESS) 71 return; 72 e = be64_to_cpu(events) & opal_event_irqchip.mask; 73 if (e) 74 goto again; 75 } 76 77 bool opal_have_pending_events(void) 78 { 79 if (last_outstanding_events & opal_event_irqchip.mask) 80 return true; 81 return false; 82 } 83 84 static void opal_event_mask(struct irq_data *d) 85 { 86 clear_bit(d->hwirq, &opal_event_irqchip.mask); 87 } 88 89 static void opal_event_unmask(struct irq_data *d) 90 { 91 set_bit(d->hwirq, &opal_event_irqchip.mask); 92 if (opal_have_pending_events()) 93 opal_wake_poller(); 94 } 95 96 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type) 97 { 98 /* 99 * For now we only support level triggered events. The irq 100 * handler will be called continuously until the event has 101 * been cleared in OPAL. 102 */ 103 if (flow_type != IRQ_TYPE_LEVEL_HIGH) 104 return -EINVAL; 105 106 return 0; 107 } 108 109 static struct opal_event_irqchip opal_event_irqchip = { 110 .irqchip = { 111 .name = "OPAL EVT", 112 .irq_mask = opal_event_mask, 113 .irq_unmask = opal_event_unmask, 114 .irq_set_type = opal_event_set_type, 115 }, 116 .mask = 0, 117 }; 118 119 static int opal_event_map(struct irq_domain *d, unsigned int irq, 120 irq_hw_number_t hwirq) 121 { 122 irq_set_chip_data(irq, &opal_event_irqchip); 123 irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip, 124 handle_level_irq); 125 126 return 0; 127 } 128 129 static irqreturn_t opal_interrupt(int irq, void *data) 130 { 131 __be64 events; 132 133 opal_handle_interrupt(virq_to_hw(irq), &events); 134 last_outstanding_events = be64_to_cpu(events); 135 if (opal_have_pending_events()) 136 opal_wake_poller(); 137 138 return IRQ_HANDLED; 139 } 140 141 static int opal_event_match(struct irq_domain *h, struct device_node *node, 142 enum irq_domain_bus_token bus_token) 143 { 144 return irq_domain_get_of_node(h) == node; 145 } 146 147 static int opal_event_xlate(struct irq_domain *h, struct device_node *np, 148 const u32 *intspec, unsigned int intsize, 149 irq_hw_number_t *out_hwirq, unsigned int *out_flags) 150 { 151 *out_hwirq = intspec[0]; 152 *out_flags = IRQ_TYPE_LEVEL_HIGH; 153 154 return 0; 155 } 156 157 static const struct irq_domain_ops opal_event_domain_ops = { 158 .match = opal_event_match, 159 .map = opal_event_map, 160 .xlate = opal_event_xlate, 161 }; 162 163 void opal_event_shutdown(void) 164 { 165 unsigned int i; 166 167 /* First free interrupts, which will also mask them */ 168 for (i = 0; i < opal_irq_count; i++) { 169 if (!opal_irqs || !opal_irqs[i].start) 170 continue; 171 172 if (in_interrupt() || irqs_disabled()) 173 disable_irq_nosync(opal_irqs[i].start); 174 else 175 free_irq(opal_irqs[i].start, NULL); 176 177 opal_irqs[i].start = 0; 178 } 179 } 180 181 int __init opal_event_init(void) 182 { 183 struct device_node *dn, *opal_node; 184 bool old_style = false; 185 int i, rc = 0; 186 187 opal_node = of_find_node_by_path("/ibm,opal"); 188 if (!opal_node) { 189 pr_warn("opal: Node not found\n"); 190 return -ENODEV; 191 } 192 193 /* If dn is NULL it means the domain won't be linked to a DT 194 * node so therefore irq_of_parse_and_map(...) wont work. But 195 * that shouldn't be problem because if we're running a 196 * version of skiboot that doesn't have the dn then the 197 * devices won't have the correct properties and will have to 198 * fall back to the legacy method (opal_event_request(...)) 199 * anyway. */ 200 dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event"); 201 opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS, 202 &opal_event_domain_ops, &opal_event_irqchip); 203 of_node_put(dn); 204 if (!opal_event_irqchip.domain) { 205 pr_warn("opal: Unable to create irq domain\n"); 206 rc = -ENOMEM; 207 goto out; 208 } 209 210 /* Look for new-style (standard) "interrupts" property */ 211 opal_irq_count = of_irq_count(opal_node); 212 213 /* Absent ? Look for the old one */ 214 if (opal_irq_count < 1) { 215 /* Get opal-interrupts property and names if present */ 216 rc = of_property_count_u32_elems(opal_node, "opal-interrupts"); 217 if (rc > 0) 218 opal_irq_count = rc; 219 old_style = true; 220 } 221 222 /* No interrupts ? Bail out */ 223 if (!opal_irq_count) 224 goto out; 225 226 pr_debug("OPAL: Found %d interrupts reserved for OPAL using %s scheme\n", 227 opal_irq_count, old_style ? "old" : "new"); 228 229 /* Allocate an IRQ resources array */ 230 opal_irqs = kcalloc(opal_irq_count, sizeof(struct resource), GFP_KERNEL); 231 if (WARN_ON(!opal_irqs)) { 232 rc = -ENOMEM; 233 goto out; 234 } 235 236 /* Build the resources array */ 237 if (old_style) { 238 /* Old style "opal-interrupts" property */ 239 for (i = 0; i < opal_irq_count; i++) { 240 struct resource *r = &opal_irqs[i]; 241 const char *name = NULL; 242 u32 hw_irq; 243 int virq; 244 245 rc = of_property_read_u32_index(opal_node, "opal-interrupts", 246 i, &hw_irq); 247 if (WARN_ON(rc < 0)) { 248 opal_irq_count = i; 249 break; 250 } 251 of_property_read_string_index(opal_node, "opal-interrupts-names", 252 i, &name); 253 virq = irq_create_mapping(NULL, hw_irq); 254 if (!virq) { 255 pr_warn("Failed to map OPAL irq 0x%x\n", hw_irq); 256 continue; 257 } 258 r->start = r->end = virq; 259 r->flags = IORESOURCE_IRQ | IRQ_TYPE_LEVEL_LOW; 260 r->name = name; 261 } 262 } else { 263 /* new style standard "interrupts" property */ 264 rc = of_irq_to_resource_table(opal_node, opal_irqs, opal_irq_count); 265 if (WARN_ON(rc < 0)) { 266 opal_irq_count = 0; 267 kfree(opal_irqs); 268 goto out; 269 } 270 if (WARN_ON(rc < opal_irq_count)) 271 opal_irq_count = rc; 272 } 273 274 /* Install interrupt handlers */ 275 for (i = 0; i < opal_irq_count; i++) { 276 struct resource *r = &opal_irqs[i]; 277 const char *name; 278 279 /* Prefix name */ 280 if (r->name && strlen(r->name)) 281 name = kasprintf(GFP_KERNEL, "opal-%s", r->name); 282 else 283 name = kasprintf(GFP_KERNEL, "opal"); 284 285 /* Install interrupt handler */ 286 rc = request_irq(r->start, opal_interrupt, r->flags & IRQD_TRIGGER_MASK, 287 name, NULL); 288 if (rc) { 289 pr_warn("Error %d requesting OPAL irq %d\n", rc, (int)r->start); 290 continue; 291 } 292 } 293 rc = 0; 294 out: 295 of_node_put(opal_node); 296 return rc; 297 } 298 machine_arch_initcall(powernv, opal_event_init); 299 300 /** 301 * opal_event_request(unsigned int opal_event_nr) - Request an event 302 * @opal_event_nr: the opal event number to request 303 * 304 * This routine can be used to find the linux virq number which can 305 * then be passed to request_irq to assign a handler for a particular 306 * opal event. This should only be used by legacy devices which don't 307 * have proper device tree bindings. Most devices should use 308 * irq_of_parse_and_map() instead. 309 */ 310 int opal_event_request(unsigned int opal_event_nr) 311 { 312 if (WARN_ON_ONCE(!opal_event_irqchip.domain)) 313 return 0; 314 315 return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr); 316 } 317 EXPORT_SYMBOL(opal_event_request); 318