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 * Return: Linux IRQ number on success or 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 separate 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 returned 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 const struct cpumask *ipimask; 119 struct irq_domain *domain; 120 unsigned int nr_irqs; 121 122 if (!irq || !data) 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 ipimask = irq_data_get_affinity_mask(data); 135 if (!ipimask || WARN_ON(!cpumask_subset(dest, ipimask))) 136 /* 137 * Must be destroying a subset of CPUs to which this IPI 138 * was set up to target 139 */ 140 return -EINVAL; 141 142 if (irq_domain_is_ipi_per_cpu(domain)) { 143 irq = irq + cpumask_first(dest) - data->common->ipi_offset; 144 nr_irqs = cpumask_weight(dest); 145 } else { 146 nr_irqs = 1; 147 } 148 149 irq_domain_free_irqs(irq, nr_irqs); 150 return 0; 151 } 152 153 /** 154 * ipi_get_hwirq - Get the hwirq associated with an IPI to a CPU 155 * @irq: Linux IRQ number 156 * @cpu: the target CPU 157 * 158 * When dealing with coprocessors IPI, we need to inform the coprocessor of 159 * the hwirq it needs to use to receive and send IPIs. 160 * 161 * Return: hwirq value on success or INVALID_HWIRQ on failure. 162 */ 163 irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu) 164 { 165 struct irq_data *data = irq_get_irq_data(irq); 166 const struct cpumask *ipimask; 167 168 if (!data || cpu >= nr_cpu_ids) 169 return INVALID_HWIRQ; 170 171 ipimask = irq_data_get_affinity_mask(data); 172 if (!ipimask || !cpumask_test_cpu(cpu, ipimask)) 173 return INVALID_HWIRQ; 174 175 /* 176 * Get the real hardware irq number if the underlying implementation 177 * uses a separate irq per cpu. If the underlying implementation uses 178 * a single hardware irq for all cpus then the IPI send mechanism 179 * needs to take care of the cpu destinations. 180 */ 181 if (irq_domain_is_ipi_per_cpu(data->domain)) 182 data = irq_get_irq_data(irq + cpu - data->common->ipi_offset); 183 184 return data ? irqd_to_hwirq(data) : INVALID_HWIRQ; 185 } 186 EXPORT_SYMBOL_GPL(ipi_get_hwirq); 187 188 static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data, 189 const struct cpumask *dest, unsigned int cpu) 190 { 191 const struct cpumask *ipimask = irq_data_get_affinity_mask(data); 192 193 if (!chip || !ipimask) 194 return -EINVAL; 195 196 if (!chip->ipi_send_single && !chip->ipi_send_mask) 197 return -EINVAL; 198 199 if (cpu >= nr_cpu_ids) 200 return -EINVAL; 201 202 if (dest) { 203 if (!cpumask_subset(dest, ipimask)) 204 return -EINVAL; 205 } else { 206 if (!cpumask_test_cpu(cpu, ipimask)) 207 return -EINVAL; 208 } 209 return 0; 210 } 211 212 /** 213 * __ipi_send_single - send an IPI to a target Linux SMP CPU 214 * @desc: pointer to irq_desc of the IRQ 215 * @cpu: destination CPU, must in the destination mask passed to 216 * irq_reserve_ipi() 217 * 218 * This function is for architecture or core code to speed up IPI sending. Not 219 * usable from driver code. 220 * 221 * Return: %0 on success or negative error number on failure. 222 */ 223 int __ipi_send_single(struct irq_desc *desc, unsigned int cpu) 224 { 225 struct irq_data *data = irq_desc_get_irq_data(desc); 226 struct irq_chip *chip = irq_data_get_irq_chip(data); 227 228 #ifdef DEBUG 229 /* 230 * Minimise the overhead by omitting the checks for Linux SMP IPIs. 231 * Since the callers should be arch or core code which is generally 232 * trusted, only check for errors when debugging. 233 */ 234 if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu))) 235 return -EINVAL; 236 #endif 237 if (!chip->ipi_send_single) { 238 chip->ipi_send_mask(data, cpumask_of(cpu)); 239 return 0; 240 } 241 242 /* FIXME: Store this information in irqdata flags */ 243 if (irq_domain_is_ipi_per_cpu(data->domain) && 244 cpu != data->common->ipi_offset) { 245 /* use the correct data for that cpu */ 246 unsigned irq = data->irq + cpu - data->common->ipi_offset; 247 248 data = irq_get_irq_data(irq); 249 } 250 chip->ipi_send_single(data, cpu); 251 return 0; 252 } 253 254 /** 255 * __ipi_send_mask - send an IPI to target Linux SMP CPU(s) 256 * @desc: pointer to irq_desc of the IRQ 257 * @dest: dest CPU(s), must be a subset of the mask passed to 258 * irq_reserve_ipi() 259 * 260 * This function is for architecture or core code to speed up IPI sending. Not 261 * usable from driver code. 262 * 263 * Return: %0 on success or negative error number on failure. 264 */ 265 int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest) 266 { 267 struct irq_data *data = irq_desc_get_irq_data(desc); 268 struct irq_chip *chip = irq_data_get_irq_chip(data); 269 unsigned int cpu; 270 271 #ifdef DEBUG 272 /* 273 * Minimise the overhead by omitting the checks for Linux SMP IPIs. 274 * Since the callers should be arch or core code which is generally 275 * trusted, only check for errors when debugging. 276 */ 277 if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0))) 278 return -EINVAL; 279 #endif 280 if (chip->ipi_send_mask) { 281 chip->ipi_send_mask(data, dest); 282 return 0; 283 } 284 285 if (irq_domain_is_ipi_per_cpu(data->domain)) { 286 unsigned int base = data->irq; 287 288 for_each_cpu(cpu, dest) { 289 unsigned irq = base + cpu - data->common->ipi_offset; 290 291 data = irq_get_irq_data(irq); 292 chip->ipi_send_single(data, cpu); 293 } 294 } else { 295 for_each_cpu(cpu, dest) 296 chip->ipi_send_single(data, cpu); 297 } 298 return 0; 299 } 300 301 /** 302 * ipi_send_single - Send an IPI to a single CPU 303 * @virq: Linux IRQ number from irq_reserve_ipi() 304 * @cpu: destination CPU, must in the destination mask passed to 305 * irq_reserve_ipi() 306 * 307 * Return: %0 on success or negative error number on failure. 308 */ 309 int ipi_send_single(unsigned int virq, unsigned int cpu) 310 { 311 struct irq_desc *desc = irq_to_desc(virq); 312 struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL; 313 struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL; 314 315 if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu))) 316 return -EINVAL; 317 318 return __ipi_send_single(desc, cpu); 319 } 320 EXPORT_SYMBOL_GPL(ipi_send_single); 321 322 /** 323 * ipi_send_mask - Send an IPI to target CPU(s) 324 * @virq: Linux IRQ number from irq_reserve_ipi() 325 * @dest: dest CPU(s), must be a subset of the mask passed to 326 * irq_reserve_ipi() 327 * 328 * Return: %0 on success or negative error number on failure. 329 */ 330 int ipi_send_mask(unsigned int virq, const struct cpumask *dest) 331 { 332 struct irq_desc *desc = irq_to_desc(virq); 333 struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL; 334 struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL; 335 336 if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0))) 337 return -EINVAL; 338 339 return __ipi_send_mask(desc, dest); 340 } 341 EXPORT_SYMBOL_GPL(ipi_send_mask); 342