1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * APM X-Gene MSI Driver 4 * 5 * Copyright (c) 2014, Applied Micro Circuits Corporation 6 * Author: Tanmay Inamdar <tinamdar@apm.com> 7 * Duc Dang <dhdang@apm.com> 8 */ 9 #include <linux/cpu.h> 10 #include <linux/interrupt.h> 11 #include <linux/module.h> 12 #include <linux/msi.h> 13 #include <linux/of_irq.h> 14 #include <linux/irqchip/chained_irq.h> 15 #include <linux/pci.h> 16 #include <linux/platform_device.h> 17 #include <linux/of_pci.h> 18 19 #define MSI_IR0 0x000000 20 #define MSI_INT0 0x800000 21 #define IDX_PER_GROUP 8 22 #define IRQS_PER_IDX 16 23 #define NR_HW_IRQS 16 24 #define NR_MSI_VEC (IDX_PER_GROUP * IRQS_PER_IDX * NR_HW_IRQS) 25 26 struct xgene_msi_group { 27 struct xgene_msi *msi; 28 int gic_irq; 29 u32 msi_grp; 30 }; 31 32 struct xgene_msi { 33 struct device_node *node; 34 struct irq_domain *inner_domain; 35 struct irq_domain *msi_domain; 36 u64 msi_addr; 37 void __iomem *msi_regs; 38 unsigned long *bitmap; 39 struct mutex bitmap_lock; 40 struct xgene_msi_group *msi_groups; 41 int num_cpus; 42 }; 43 44 /* Global data */ 45 static struct xgene_msi xgene_msi_ctrl; 46 47 static struct irq_chip xgene_msi_top_irq_chip = { 48 .name = "X-Gene1 MSI", 49 .irq_enable = pci_msi_unmask_irq, 50 .irq_disable = pci_msi_mask_irq, 51 .irq_mask = pci_msi_mask_irq, 52 .irq_unmask = pci_msi_unmask_irq, 53 }; 54 55 static struct msi_domain_info xgene_msi_domain_info = { 56 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | 57 MSI_FLAG_PCI_MSIX), 58 .chip = &xgene_msi_top_irq_chip, 59 }; 60 61 /* 62 * X-Gene v1 has 16 groups of MSI termination registers MSInIRx, where 63 * n is group number (0..F), x is index of registers in each group (0..7) 64 * The register layout is as follows: 65 * MSI0IR0 base_addr 66 * MSI0IR1 base_addr + 0x10000 67 * ... ... 68 * MSI0IR6 base_addr + 0x60000 69 * MSI0IR7 base_addr + 0x70000 70 * MSI1IR0 base_addr + 0x80000 71 * MSI1IR1 base_addr + 0x90000 72 * ... ... 73 * MSI1IR7 base_addr + 0xF0000 74 * MSI2IR0 base_addr + 0x100000 75 * ... ... 76 * MSIFIR0 base_addr + 0x780000 77 * MSIFIR1 base_addr + 0x790000 78 * ... ... 79 * MSIFIR7 base_addr + 0x7F0000 80 * MSIINT0 base_addr + 0x800000 81 * MSIINT1 base_addr + 0x810000 82 * ... ... 83 * MSIINTF base_addr + 0x8F0000 84 * 85 * Each index register supports 16 MSI vectors (0..15) to generate interrupt. 86 * There are total 16 GIC IRQs assigned for these 16 groups of MSI termination 87 * registers. 88 * 89 * Each MSI termination group has 1 MSIINTn register (n is 0..15) to indicate 90 * the MSI pending status caused by 1 of its 8 index registers. 91 */ 92 93 /* MSInIRx read helper */ 94 static u32 xgene_msi_ir_read(struct xgene_msi *msi, 95 u32 msi_grp, u32 msir_idx) 96 { 97 return readl_relaxed(msi->msi_regs + MSI_IR0 + 98 (msi_grp << 19) + (msir_idx << 16)); 99 } 100 101 /* MSIINTn read helper */ 102 static u32 xgene_msi_int_read(struct xgene_msi *msi, u32 msi_grp) 103 { 104 return readl_relaxed(msi->msi_regs + MSI_INT0 + (msi_grp << 16)); 105 } 106 107 /* 108 * With 2048 MSI vectors supported, the MSI message can be constructed using 109 * following scheme: 110 * - Divide into 8 256-vector groups 111 * Group 0: 0-255 112 * Group 1: 256-511 113 * Group 2: 512-767 114 * ... 115 * Group 7: 1792-2047 116 * - Each 256-vector group is divided into 16 16-vector groups 117 * As an example: 16 16-vector groups for 256-vector group 0-255 is 118 * Group 0: 0-15 119 * Group 1: 16-32 120 * ... 121 * Group 15: 240-255 122 * - The termination address of MSI vector in 256-vector group n and 16-vector 123 * group x is the address of MSIxIRn 124 * - The data for MSI vector in 16-vector group x is x 125 */ 126 static u32 hwirq_to_reg_set(unsigned long hwirq) 127 { 128 return (hwirq / (NR_HW_IRQS * IRQS_PER_IDX)); 129 } 130 131 static u32 hwirq_to_group(unsigned long hwirq) 132 { 133 return (hwirq % NR_HW_IRQS); 134 } 135 136 static u32 hwirq_to_msi_data(unsigned long hwirq) 137 { 138 return ((hwirq / NR_HW_IRQS) % IRQS_PER_IDX); 139 } 140 141 static void xgene_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) 142 { 143 struct xgene_msi *msi = irq_data_get_irq_chip_data(data); 144 u32 reg_set = hwirq_to_reg_set(data->hwirq); 145 u32 group = hwirq_to_group(data->hwirq); 146 u64 target_addr = msi->msi_addr + (((8 * group) + reg_set) << 16); 147 148 msg->address_hi = upper_32_bits(target_addr); 149 msg->address_lo = lower_32_bits(target_addr); 150 msg->data = hwirq_to_msi_data(data->hwirq); 151 } 152 153 /* 154 * X-Gene v1 only has 16 MSI GIC IRQs for 2048 MSI vectors. To maintain 155 * the expected behaviour of .set_affinity for each MSI interrupt, the 16 156 * MSI GIC IRQs are statically allocated to 8 X-Gene v1 cores (2 GIC IRQs 157 * for each core). The MSI vector is moved fom 1 MSI GIC IRQ to another 158 * MSI GIC IRQ to steer its MSI interrupt to correct X-Gene v1 core. As a 159 * consequence, the total MSI vectors that X-Gene v1 supports will be 160 * reduced to 256 (2048/8) vectors. 161 */ 162 static int hwirq_to_cpu(unsigned long hwirq) 163 { 164 return (hwirq % xgene_msi_ctrl.num_cpus); 165 } 166 167 static unsigned long hwirq_to_canonical_hwirq(unsigned long hwirq) 168 { 169 return (hwirq - hwirq_to_cpu(hwirq)); 170 } 171 172 static int xgene_msi_set_affinity(struct irq_data *irqdata, 173 const struct cpumask *mask, bool force) 174 { 175 int target_cpu = cpumask_first(mask); 176 int curr_cpu; 177 178 curr_cpu = hwirq_to_cpu(irqdata->hwirq); 179 if (curr_cpu == target_cpu) 180 return IRQ_SET_MASK_OK_DONE; 181 182 /* Update MSI number to target the new CPU */ 183 irqdata->hwirq = hwirq_to_canonical_hwirq(irqdata->hwirq) + target_cpu; 184 185 return IRQ_SET_MASK_OK; 186 } 187 188 static struct irq_chip xgene_msi_bottom_irq_chip = { 189 .name = "MSI", 190 .irq_set_affinity = xgene_msi_set_affinity, 191 .irq_compose_msi_msg = xgene_compose_msi_msg, 192 }; 193 194 static int xgene_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, 195 unsigned int nr_irqs, void *args) 196 { 197 struct xgene_msi *msi = domain->host_data; 198 int msi_irq; 199 200 mutex_lock(&msi->bitmap_lock); 201 202 msi_irq = bitmap_find_next_zero_area(msi->bitmap, NR_MSI_VEC, 0, 203 msi->num_cpus, 0); 204 if (msi_irq < NR_MSI_VEC) 205 bitmap_set(msi->bitmap, msi_irq, msi->num_cpus); 206 else 207 msi_irq = -ENOSPC; 208 209 mutex_unlock(&msi->bitmap_lock); 210 211 if (msi_irq < 0) 212 return msi_irq; 213 214 irq_domain_set_info(domain, virq, msi_irq, 215 &xgene_msi_bottom_irq_chip, domain->host_data, 216 handle_simple_irq, NULL, NULL); 217 218 return 0; 219 } 220 221 static void xgene_irq_domain_free(struct irq_domain *domain, 222 unsigned int virq, unsigned int nr_irqs) 223 { 224 struct irq_data *d = irq_domain_get_irq_data(domain, virq); 225 struct xgene_msi *msi = irq_data_get_irq_chip_data(d); 226 u32 hwirq; 227 228 mutex_lock(&msi->bitmap_lock); 229 230 hwirq = hwirq_to_canonical_hwirq(d->hwirq); 231 bitmap_clear(msi->bitmap, hwirq, msi->num_cpus); 232 233 mutex_unlock(&msi->bitmap_lock); 234 235 irq_domain_free_irqs_parent(domain, virq, nr_irqs); 236 } 237 238 static const struct irq_domain_ops msi_domain_ops = { 239 .alloc = xgene_irq_domain_alloc, 240 .free = xgene_irq_domain_free, 241 }; 242 243 static int xgene_allocate_domains(struct xgene_msi *msi) 244 { 245 msi->inner_domain = irq_domain_add_linear(NULL, NR_MSI_VEC, 246 &msi_domain_ops, msi); 247 if (!msi->inner_domain) 248 return -ENOMEM; 249 250 msi->msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(msi->node), 251 &xgene_msi_domain_info, 252 msi->inner_domain); 253 254 if (!msi->msi_domain) { 255 irq_domain_remove(msi->inner_domain); 256 return -ENOMEM; 257 } 258 259 return 0; 260 } 261 262 static void xgene_free_domains(struct xgene_msi *msi) 263 { 264 if (msi->msi_domain) 265 irq_domain_remove(msi->msi_domain); 266 if (msi->inner_domain) 267 irq_domain_remove(msi->inner_domain); 268 } 269 270 static int xgene_msi_init_allocator(struct xgene_msi *xgene_msi) 271 { 272 int size = BITS_TO_LONGS(NR_MSI_VEC) * sizeof(long); 273 274 xgene_msi->bitmap = kzalloc(size, GFP_KERNEL); 275 if (!xgene_msi->bitmap) 276 return -ENOMEM; 277 278 mutex_init(&xgene_msi->bitmap_lock); 279 280 xgene_msi->msi_groups = kcalloc(NR_HW_IRQS, 281 sizeof(struct xgene_msi_group), 282 GFP_KERNEL); 283 if (!xgene_msi->msi_groups) 284 return -ENOMEM; 285 286 return 0; 287 } 288 289 static void xgene_msi_isr(struct irq_desc *desc) 290 { 291 struct irq_chip *chip = irq_desc_get_chip(desc); 292 struct xgene_msi_group *msi_groups; 293 struct xgene_msi *xgene_msi; 294 int msir_index, msir_val, hw_irq, ret; 295 u32 intr_index, grp_select, msi_grp; 296 297 chained_irq_enter(chip, desc); 298 299 msi_groups = irq_desc_get_handler_data(desc); 300 xgene_msi = msi_groups->msi; 301 msi_grp = msi_groups->msi_grp; 302 303 /* 304 * MSIINTn (n is 0..F) indicates if there is a pending MSI interrupt 305 * If bit x of this register is set (x is 0..7), one or more interupts 306 * corresponding to MSInIRx is set. 307 */ 308 grp_select = xgene_msi_int_read(xgene_msi, msi_grp); 309 while (grp_select) { 310 msir_index = ffs(grp_select) - 1; 311 /* 312 * Calculate MSInIRx address to read to check for interrupts 313 * (refer to termination address and data assignment 314 * described in xgene_compose_msi_msg() ) 315 */ 316 msir_val = xgene_msi_ir_read(xgene_msi, msi_grp, msir_index); 317 while (msir_val) { 318 intr_index = ffs(msir_val) - 1; 319 /* 320 * Calculate MSI vector number (refer to the termination 321 * address and data assignment described in 322 * xgene_compose_msi_msg function) 323 */ 324 hw_irq = (((msir_index * IRQS_PER_IDX) + intr_index) * 325 NR_HW_IRQS) + msi_grp; 326 /* 327 * As we have multiple hw_irq that maps to single MSI, 328 * always look up the virq using the hw_irq as seen from 329 * CPU0 330 */ 331 hw_irq = hwirq_to_canonical_hwirq(hw_irq); 332 ret = generic_handle_domain_irq(xgene_msi->inner_domain, hw_irq); 333 WARN_ON_ONCE(ret); 334 msir_val &= ~(1 << intr_index); 335 } 336 grp_select &= ~(1 << msir_index); 337 338 if (!grp_select) { 339 /* 340 * We handled all interrupts happened in this group, 341 * resample this group MSI_INTx register in case 342 * something else has been made pending in the meantime 343 */ 344 grp_select = xgene_msi_int_read(xgene_msi, msi_grp); 345 } 346 } 347 348 chained_irq_exit(chip, desc); 349 } 350 351 static enum cpuhp_state pci_xgene_online; 352 353 static int xgene_msi_remove(struct platform_device *pdev) 354 { 355 struct xgene_msi *msi = platform_get_drvdata(pdev); 356 357 if (pci_xgene_online) 358 cpuhp_remove_state(pci_xgene_online); 359 cpuhp_remove_state(CPUHP_PCI_XGENE_DEAD); 360 361 kfree(msi->msi_groups); 362 363 kfree(msi->bitmap); 364 msi->bitmap = NULL; 365 366 xgene_free_domains(msi); 367 368 return 0; 369 } 370 371 static int xgene_msi_hwirq_alloc(unsigned int cpu) 372 { 373 struct xgene_msi *msi = &xgene_msi_ctrl; 374 struct xgene_msi_group *msi_group; 375 cpumask_var_t mask; 376 int i; 377 int err; 378 379 for (i = cpu; i < NR_HW_IRQS; i += msi->num_cpus) { 380 msi_group = &msi->msi_groups[i]; 381 if (!msi_group->gic_irq) 382 continue; 383 384 irq_set_chained_handler_and_data(msi_group->gic_irq, 385 xgene_msi_isr, msi_group); 386 387 /* 388 * Statically allocate MSI GIC IRQs to each CPU core. 389 * With 8-core X-Gene v1, 2 MSI GIC IRQs are allocated 390 * to each core. 391 */ 392 if (alloc_cpumask_var(&mask, GFP_KERNEL)) { 393 cpumask_clear(mask); 394 cpumask_set_cpu(cpu, mask); 395 err = irq_set_affinity(msi_group->gic_irq, mask); 396 if (err) 397 pr_err("failed to set affinity for GIC IRQ"); 398 free_cpumask_var(mask); 399 } else { 400 pr_err("failed to alloc CPU mask for affinity\n"); 401 err = -EINVAL; 402 } 403 404 if (err) { 405 irq_set_chained_handler_and_data(msi_group->gic_irq, 406 NULL, NULL); 407 return err; 408 } 409 } 410 411 return 0; 412 } 413 414 static int xgene_msi_hwirq_free(unsigned int cpu) 415 { 416 struct xgene_msi *msi = &xgene_msi_ctrl; 417 struct xgene_msi_group *msi_group; 418 int i; 419 420 for (i = cpu; i < NR_HW_IRQS; i += msi->num_cpus) { 421 msi_group = &msi->msi_groups[i]; 422 if (!msi_group->gic_irq) 423 continue; 424 425 irq_set_chained_handler_and_data(msi_group->gic_irq, NULL, 426 NULL); 427 } 428 return 0; 429 } 430 431 static const struct of_device_id xgene_msi_match_table[] = { 432 {.compatible = "apm,xgene1-msi"}, 433 {}, 434 }; 435 436 static int xgene_msi_probe(struct platform_device *pdev) 437 { 438 struct resource *res; 439 int rc, irq_index; 440 struct xgene_msi *xgene_msi; 441 int virt_msir; 442 u32 msi_val, msi_idx; 443 444 xgene_msi = &xgene_msi_ctrl; 445 446 platform_set_drvdata(pdev, xgene_msi); 447 448 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 449 xgene_msi->msi_regs = devm_ioremap_resource(&pdev->dev, res); 450 if (IS_ERR(xgene_msi->msi_regs)) { 451 rc = PTR_ERR(xgene_msi->msi_regs); 452 goto error; 453 } 454 xgene_msi->msi_addr = res->start; 455 xgene_msi->node = pdev->dev.of_node; 456 xgene_msi->num_cpus = num_possible_cpus(); 457 458 rc = xgene_msi_init_allocator(xgene_msi); 459 if (rc) { 460 dev_err(&pdev->dev, "Error allocating MSI bitmap\n"); 461 goto error; 462 } 463 464 rc = xgene_allocate_domains(xgene_msi); 465 if (rc) { 466 dev_err(&pdev->dev, "Failed to allocate MSI domain\n"); 467 goto error; 468 } 469 470 for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) { 471 virt_msir = platform_get_irq(pdev, irq_index); 472 if (virt_msir < 0) { 473 rc = virt_msir; 474 goto error; 475 } 476 xgene_msi->msi_groups[irq_index].gic_irq = virt_msir; 477 xgene_msi->msi_groups[irq_index].msi_grp = irq_index; 478 xgene_msi->msi_groups[irq_index].msi = xgene_msi; 479 } 480 481 /* 482 * MSInIRx registers are read-to-clear; before registering 483 * interrupt handlers, read all of them to clear spurious 484 * interrupts that may occur before the driver is probed. 485 */ 486 for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) { 487 for (msi_idx = 0; msi_idx < IDX_PER_GROUP; msi_idx++) 488 xgene_msi_ir_read(xgene_msi, irq_index, msi_idx); 489 490 /* Read MSIINTn to confirm */ 491 msi_val = xgene_msi_int_read(xgene_msi, irq_index); 492 if (msi_val) { 493 dev_err(&pdev->dev, "Failed to clear spurious IRQ\n"); 494 rc = -EINVAL; 495 goto error; 496 } 497 } 498 499 rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/xgene:online", 500 xgene_msi_hwirq_alloc, NULL); 501 if (rc < 0) 502 goto err_cpuhp; 503 pci_xgene_online = rc; 504 rc = cpuhp_setup_state(CPUHP_PCI_XGENE_DEAD, "pci/xgene:dead", NULL, 505 xgene_msi_hwirq_free); 506 if (rc) 507 goto err_cpuhp; 508 509 dev_info(&pdev->dev, "APM X-Gene PCIe MSI driver loaded\n"); 510 511 return 0; 512 513 err_cpuhp: 514 dev_err(&pdev->dev, "failed to add CPU MSI notifier\n"); 515 error: 516 xgene_msi_remove(pdev); 517 return rc; 518 } 519 520 static struct platform_driver xgene_msi_driver = { 521 .driver = { 522 .name = "xgene-msi", 523 .of_match_table = xgene_msi_match_table, 524 }, 525 .probe = xgene_msi_probe, 526 .remove = xgene_msi_remove, 527 }; 528 529 static int __init xgene_pcie_msi_init(void) 530 { 531 return platform_driver_register(&xgene_msi_driver); 532 } 533 subsys_initcall(xgene_pcie_msi_init); 534