1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2015 Imagination Technologies Ltd 4 * Author: Qais Yousef <qais.yousef@imgtec.com> 5 * 6 * This file contains driver APIs to the IPI subsystem. 7 */ 8 9 #define pr_fmt(fmt) "genirq/ipi: " fmt 10 11 #include <linux/irqdomain.h> 12 #include <linux/irq.h> 13 14 /** 15 * irq_reserve_ipi() - Setup an IPI to destination cpumask 16 * @domain: IPI domain 17 * @dest: cpumask of cpus which can receive the IPI 18 * 19 * Allocate a virq that can be used to send IPI to any CPU in dest mask. 20 * 21 * On success it'll return linux irq number and error code on failure 22 */ 23 int irq_reserve_ipi(struct irq_domain *domain, 24 const struct cpumask *dest) 25 { 26 unsigned int nr_irqs, offset; 27 struct irq_data *data; 28 int virq, i; 29 30 if (!domain ||!irq_domain_is_ipi(domain)) { 31 pr_warn("Reservation on a non IPI domain\n"); 32 return -EINVAL; 33 } 34 35 if (!cpumask_subset(dest, cpu_possible_mask)) { 36 pr_warn("Reservation is not in possible_cpu_mask\n"); 37 return -EINVAL; 38 } 39 40 nr_irqs = cpumask_weight(dest); 41 if (!nr_irqs) { 42 pr_warn("Reservation for empty destination mask\n"); 43 return -EINVAL; 44 } 45 46 if (irq_domain_is_ipi_single(domain)) { 47 /* 48 * If the underlying implementation uses a single HW irq on 49 * all cpus then we only need a single Linux irq number for 50 * it. We have no restrictions vs. the destination mask. The 51 * underlying implementation can deal with holes nicely. 52 */ 53 nr_irqs = 1; 54 offset = 0; 55 } else { 56 unsigned int next; 57 58 /* 59 * The IPI requires a seperate HW irq on each CPU. We require 60 * that the destination mask is consecutive. If an 61 * implementation needs to support holes, it can reserve 62 * several IPI ranges. 63 */ 64 offset = cpumask_first(dest); 65 /* 66 * Find a hole and if found look for another set bit after the 67 * hole. For now we don't support this scenario. 68 */ 69 next = cpumask_next_zero(offset, dest); 70 if (next < nr_cpu_ids) 71 next = cpumask_next(next, dest); 72 if (next < nr_cpu_ids) { 73 pr_warn("Destination mask has holes\n"); 74 return -EINVAL; 75 } 76 } 77 78 virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL); 79 if (virq <= 0) { 80 pr_warn("Can't reserve IPI, failed to alloc descs\n"); 81 return -ENOMEM; 82 } 83 84 virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE, 85 (void *) dest, true, NULL); 86 87 if (virq <= 0) { 88 pr_warn("Can't reserve IPI, failed to alloc hw irqs\n"); 89 goto free_descs; 90 } 91 92 for (i = 0; i < nr_irqs; i++) { 93 data = irq_get_irq_data(virq + i); 94 cpumask_copy(data->common->affinity, dest); 95 data->common->ipi_offset = offset; 96 irq_set_status_flags(virq + i, IRQ_NO_BALANCING); 97 } 98 return virq; 99 100 free_descs: 101 irq_free_descs(virq, nr_irqs); 102 return -EBUSY; 103 } 104 105 /** 106 * irq_destroy_ipi() - unreserve an IPI that was previously allocated 107 * @irq: linux irq number to be destroyed 108 * @dest: cpumask of cpus which should have the IPI removed 109 * 110 * The IPIs allocated with irq_reserve_ipi() are retuerned to the system 111 * destroying all virqs associated with them. 112 * 113 * Return 0 on success or error code on failure. 114 */ 115 int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest) 116 { 117 struct irq_data *data = irq_get_irq_data(irq); 118 struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL; 119 struct irq_domain *domain; 120 unsigned int nr_irqs; 121 122 if (!irq || !data || !ipimask) 123 return -EINVAL; 124 125 domain = data->domain; 126 if (WARN_ON(domain == NULL)) 127 return -EINVAL; 128 129 if (!irq_domain_is_ipi(domain)) { 130 pr_warn("Trying to destroy a non IPI domain!\n"); 131 return -EINVAL; 132 } 133 134 if (WARN_ON(!cpumask_subset(dest, ipimask))) 135 /* 136 * Must be destroying a subset of CPUs to which this IPI 137 * was set up to target 138 */ 139 return -EINVAL; 140 141 if (irq_domain_is_ipi_per_cpu(domain)) { 142 irq = irq + cpumask_first(dest) - data->common->ipi_offset; 143 nr_irqs = cpumask_weight(dest); 144 } else { 145 nr_irqs = 1; 146 } 147 148 irq_domain_free_irqs(irq, nr_irqs); 149 return 0; 150 } 151 152 /** 153 * ipi_get_hwirq - Get the hwirq associated with an IPI to a cpu 154 * @irq: linux irq number 155 * @cpu: the target cpu 156 * 157 * When dealing with coprocessors IPI, we need to inform the coprocessor of 158 * the hwirq it needs to use to receive and send IPIs. 159 * 160 * Returns hwirq value on success and INVALID_HWIRQ on failure. 161 */ 162 irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu) 163 { 164 struct irq_data *data = irq_get_irq_data(irq); 165 struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL; 166 167 if (!data || !ipimask || cpu >= nr_cpu_ids) 168 return INVALID_HWIRQ; 169 170 if (!cpumask_test_cpu(cpu, ipimask)) 171 return INVALID_HWIRQ; 172 173 /* 174 * Get the real hardware irq number if the underlying implementation 175 * uses a seperate irq per cpu. If the underlying implementation uses 176 * a single hardware irq for all cpus then the IPI send mechanism 177 * needs to take care of the cpu destinations. 178 */ 179 if (irq_domain_is_ipi_per_cpu(data->domain)) 180 data = irq_get_irq_data(irq + cpu - data->common->ipi_offset); 181 182 return data ? irqd_to_hwirq(data) : INVALID_HWIRQ; 183 } 184 EXPORT_SYMBOL_GPL(ipi_get_hwirq); 185 186 static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data, 187 const struct cpumask *dest, unsigned int cpu) 188 { 189 struct cpumask *ipimask = irq_data_get_affinity_mask(data); 190 191 if (!chip || !ipimask) 192 return -EINVAL; 193 194 if (!chip->ipi_send_single && !chip->ipi_send_mask) 195 return -EINVAL; 196 197 if (cpu >= nr_cpu_ids) 198 return -EINVAL; 199 200 if (dest) { 201 if (!cpumask_subset(dest, ipimask)) 202 return -EINVAL; 203 } else { 204 if (!cpumask_test_cpu(cpu, ipimask)) 205 return -EINVAL; 206 } 207 return 0; 208 } 209 210 /** 211 * __ipi_send_single - send an IPI to a target Linux SMP CPU 212 * @desc: pointer to irq_desc of the IRQ 213 * @cpu: destination CPU, must in the destination mask passed to 214 * irq_reserve_ipi() 215 * 216 * This function is for architecture or core code to speed up IPI sending. Not 217 * usable from driver code. 218 * 219 * Returns zero on success and negative error number on failure. 220 */ 221 int __ipi_send_single(struct irq_desc *desc, unsigned int cpu) 222 { 223 struct irq_data *data = irq_desc_get_irq_data(desc); 224 struct irq_chip *chip = irq_data_get_irq_chip(data); 225 226 #ifdef DEBUG 227 /* 228 * Minimise the overhead by omitting the checks for Linux SMP IPIs. 229 * Since the callers should be arch or core code which is generally 230 * trusted, only check for errors when debugging. 231 */ 232 if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu))) 233 return -EINVAL; 234 #endif 235 if (!chip->ipi_send_single) { 236 chip->ipi_send_mask(data, cpumask_of(cpu)); 237 return 0; 238 } 239 240 /* FIXME: Store this information in irqdata flags */ 241 if (irq_domain_is_ipi_per_cpu(data->domain) && 242 cpu != data->common->ipi_offset) { 243 /* use the correct data for that cpu */ 244 unsigned irq = data->irq + cpu - data->common->ipi_offset; 245 246 data = irq_get_irq_data(irq); 247 } 248 chip->ipi_send_single(data, cpu); 249 return 0; 250 } 251 252 /** 253 * ipi_send_mask - send an IPI to target Linux SMP CPU(s) 254 * @desc: pointer to irq_desc of the IRQ 255 * @dest: dest CPU(s), must be a subset of the mask passed to 256 * irq_reserve_ipi() 257 * 258 * This function is for architecture or core code to speed up IPI sending. Not 259 * usable from driver code. 260 * 261 * Returns zero on success and negative error number on failure. 262 */ 263 int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest) 264 { 265 struct irq_data *data = irq_desc_get_irq_data(desc); 266 struct irq_chip *chip = irq_data_get_irq_chip(data); 267 unsigned int cpu; 268 269 #ifdef DEBUG 270 /* 271 * Minimise the overhead by omitting the checks for Linux SMP IPIs. 272 * Since the callers should be arch or core code which is generally 273 * trusted, only check for errors when debugging. 274 */ 275 if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0))) 276 return -EINVAL; 277 #endif 278 if (chip->ipi_send_mask) { 279 chip->ipi_send_mask(data, dest); 280 return 0; 281 } 282 283 if (irq_domain_is_ipi_per_cpu(data->domain)) { 284 unsigned int base = data->irq; 285 286 for_each_cpu(cpu, dest) { 287 unsigned irq = base + cpu - data->common->ipi_offset; 288 289 data = irq_get_irq_data(irq); 290 chip->ipi_send_single(data, cpu); 291 } 292 } else { 293 for_each_cpu(cpu, dest) 294 chip->ipi_send_single(data, cpu); 295 } 296 return 0; 297 } 298 299 /** 300 * ipi_send_single - Send an IPI to a single CPU 301 * @virq: linux irq number from irq_reserve_ipi() 302 * @cpu: destination CPU, must in the destination mask passed to 303 * irq_reserve_ipi() 304 * 305 * Returns zero on success and negative error number on failure. 306 */ 307 int ipi_send_single(unsigned int virq, unsigned int cpu) 308 { 309 struct irq_desc *desc = irq_to_desc(virq); 310 struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL; 311 struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL; 312 313 if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu))) 314 return -EINVAL; 315 316 return __ipi_send_single(desc, cpu); 317 } 318 EXPORT_SYMBOL_GPL(ipi_send_single); 319 320 /** 321 * ipi_send_mask - Send an IPI to target CPU(s) 322 * @virq: linux irq number from irq_reserve_ipi() 323 * @dest: dest CPU(s), must be a subset of the mask passed to 324 * irq_reserve_ipi() 325 * 326 * Returns zero on success and negative error number on failure. 327 */ 328 int ipi_send_mask(unsigned int virq, const struct cpumask *dest) 329 { 330 struct irq_desc *desc = irq_to_desc(virq); 331 struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL; 332 struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL; 333 334 if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0))) 335 return -EINVAL; 336 337 return __ipi_send_mask(desc, dest); 338 } 339 EXPORT_SYMBOL_GPL(ipi_send_mask); 340