linux/drivers/acpi/arm64/gtdt.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * ARM Specific GTDT table Support
   4 *
   5 * Copyright (C) 2016, Linaro Ltd.
   6 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
   7 *         Fu Wei <fu.wei@linaro.org>
   8 *         Hanjun Guo <hanjun.guo@linaro.org>
   9 */
  10
  11#include <linux/acpi.h>
  12#include <linux/init.h>
  13#include <linux/irqdomain.h>
  14#include <linux/kernel.h>
  15#include <linux/platform_device.h>
  16
  17#include <clocksource/arm_arch_timer.h>
  18
  19#undef pr_fmt
  20#define pr_fmt(fmt) "ACPI GTDT: " fmt
  21
  22/**
  23 * struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
  24 * @gtdt:       The pointer to the struct acpi_table_gtdt of GTDT table.
  25 * @gtdt_end:   The pointer to the end of GTDT table.
  26 * @platform_timer:     The pointer to the start of Platform Timer Structure
  27 *
  28 * The struct store the key info of GTDT table, it should be initialized by
  29 * acpi_gtdt_init.
  30 */
  31struct acpi_gtdt_descriptor {
  32        struct acpi_table_gtdt *gtdt;
  33        void *gtdt_end;
  34        void *platform_timer;
  35};
  36
  37static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;
  38
  39static inline void *next_platform_timer(void *platform_timer)
  40{
  41        struct acpi_gtdt_header *gh = platform_timer;
  42
  43        platform_timer += gh->length;
  44        if (platform_timer < acpi_gtdt_desc.gtdt_end)
  45                return platform_timer;
  46
  47        return NULL;
  48}
  49
  50#define for_each_platform_timer(_g)                             \
  51        for (_g = acpi_gtdt_desc.platform_timer; _g;    \
  52             _g = next_platform_timer(_g))
  53
  54static inline bool is_timer_block(void *platform_timer)
  55{
  56        struct acpi_gtdt_header *gh = platform_timer;
  57
  58        return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;
  59}
  60
  61static inline bool is_non_secure_watchdog(void *platform_timer)
  62{
  63        struct acpi_gtdt_header *gh = platform_timer;
  64        struct acpi_gtdt_watchdog *wd = platform_timer;
  65
  66        if (gh->type != ACPI_GTDT_TYPE_WATCHDOG)
  67                return false;
  68
  69        return !(wd->timer_flags & ACPI_GTDT_WATCHDOG_SECURE);
  70}
  71
  72static int __init map_gt_gsi(u32 interrupt, u32 flags)
  73{
  74        int trigger, polarity;
  75
  76        trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
  77                        : ACPI_LEVEL_SENSITIVE;
  78
  79        polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
  80                        : ACPI_ACTIVE_HIGH;
  81
  82        return acpi_register_gsi(NULL, interrupt, trigger, polarity);
  83}
  84
  85/**
  86 * acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
  87 * @type:       the type of PPI.
  88 *
  89 * Note: Secure state is not managed by the kernel on ARM64 systems.
  90 * So we only handle the non-secure timer PPIs,
  91 * ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
  92 *
  93 * Return: the mapped PPI value, 0 if error.
  94 */
  95int __init acpi_gtdt_map_ppi(int type)
  96{
  97        struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  98
  99        switch (type) {
 100        case ARCH_TIMER_PHYS_NONSECURE_PPI:
 101                return map_gt_gsi(gtdt->non_secure_el1_interrupt,
 102                                  gtdt->non_secure_el1_flags);
 103        case ARCH_TIMER_VIRT_PPI:
 104                return map_gt_gsi(gtdt->virtual_timer_interrupt,
 105                                  gtdt->virtual_timer_flags);
 106
 107        case ARCH_TIMER_HYP_PPI:
 108                return map_gt_gsi(gtdt->non_secure_el2_interrupt,
 109                                  gtdt->non_secure_el2_flags);
 110        default:
 111                pr_err("Failed to map timer interrupt: invalid type.\n");
 112        }
 113
 114        return 0;
 115}
 116
 117/**
 118 * acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
 119 * @type:       the type of PPI.
 120 *
 121 * Return: true if the timer HW state is lost when a CPU enters an idle state,
 122 * false otherwise
 123 */
 124bool __init acpi_gtdt_c3stop(int type)
 125{
 126        struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
 127
 128        switch (type) {
 129        case ARCH_TIMER_PHYS_NONSECURE_PPI:
 130                return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
 131
 132        case ARCH_TIMER_VIRT_PPI:
 133                return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);
 134
 135        case ARCH_TIMER_HYP_PPI:
 136                return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
 137
 138        default:
 139                pr_err("Failed to get c3stop info: invalid type.\n");
 140        }
 141
 142        return false;
 143}
 144
 145/**
 146 * acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
 147 * @table:                      The pointer to GTDT table.
 148 * @platform_timer_count:       It points to a integer variable which is used
 149 *                              for storing the number of platform timers.
 150 *                              This pointer could be NULL, if the caller
 151 *                              doesn't need this info.
 152 *
 153 * Return: 0 if success, -EINVAL if error.
 154 */
 155int __init acpi_gtdt_init(struct acpi_table_header *table,
 156                          int *platform_timer_count)
 157{
 158        void *platform_timer;
 159        struct acpi_table_gtdt *gtdt;
 160
 161        gtdt = container_of(table, struct acpi_table_gtdt, header);
 162        acpi_gtdt_desc.gtdt = gtdt;
 163        acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
 164        acpi_gtdt_desc.platform_timer = NULL;
 165        if (platform_timer_count)
 166                *platform_timer_count = 0;
 167
 168        if (table->revision < 2) {
 169                pr_warn("Revision:%d doesn't support Platform Timers.\n",
 170                        table->revision);
 171                return 0;
 172        }
 173
 174        if (!gtdt->platform_timer_count) {
 175                pr_debug("No Platform Timer.\n");
 176                return 0;
 177        }
 178
 179        platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
 180        if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
 181                pr_err(FW_BUG "invalid timer data.\n");
 182                return -EINVAL;
 183        }
 184        acpi_gtdt_desc.platform_timer = platform_timer;
 185        if (platform_timer_count)
 186                *platform_timer_count = gtdt->platform_timer_count;
 187
 188        return 0;
 189}
 190
 191static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,
 192                                         struct arch_timer_mem *timer_mem)
 193{
 194        int i;
 195        struct arch_timer_mem_frame *frame;
 196        struct acpi_gtdt_timer_entry *gtdt_frame;
 197
 198        if (!block->timer_count) {
 199                pr_err(FW_BUG "GT block present, but frame count is zero.\n");
 200                return -ENODEV;
 201        }
 202
 203        if (block->timer_count > ARCH_TIMER_MEM_MAX_FRAMES) {
 204                pr_err(FW_BUG "GT block lists %d frames, ACPI spec only allows 8\n",
 205                       block->timer_count);
 206                return -EINVAL;
 207        }
 208
 209        timer_mem->cntctlbase = (phys_addr_t)block->block_address;
 210        /*
 211         * The CNTCTLBase frame is 4KB (register offsets 0x000 - 0xFFC).
 212         * See ARM DDI 0487A.k_iss10775, page I1-5129, Table I1-3
 213         * "CNTCTLBase memory map".
 214         */
 215        timer_mem->size = SZ_4K;
 216
 217        gtdt_frame = (void *)block + block->timer_offset;
 218        if (gtdt_frame + block->timer_count != (void *)block + block->header.length)
 219                return -EINVAL;
 220
 221        /*
 222         * Get the GT timer Frame data for every GT Block Timer
 223         */
 224        for (i = 0; i < block->timer_count; i++, gtdt_frame++) {
 225                if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER)
 226                        continue;
 227                if (gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES ||
 228                    !gtdt_frame->base_address || !gtdt_frame->timer_interrupt)
 229                        goto error;
 230
 231                frame = &timer_mem->frame[gtdt_frame->frame_number];
 232
 233                /* duplicate frame */
 234                if (frame->valid)
 235                        goto error;
 236
 237                frame->phys_irq = map_gt_gsi(gtdt_frame->timer_interrupt,
 238                                             gtdt_frame->timer_flags);
 239                if (frame->phys_irq <= 0) {
 240                        pr_warn("failed to map physical timer irq in frame %d.\n",
 241                                gtdt_frame->frame_number);
 242                        goto error;
 243                }
 244
 245                if (gtdt_frame->virtual_timer_interrupt) {
 246                        frame->virt_irq =
 247                                map_gt_gsi(gtdt_frame->virtual_timer_interrupt,
 248                                           gtdt_frame->virtual_timer_flags);
 249                        if (frame->virt_irq <= 0) {
 250                                pr_warn("failed to map virtual timer irq in frame %d.\n",
 251                                        gtdt_frame->frame_number);
 252                                goto error;
 253                        }
 254                } else {
 255                        pr_debug("virtual timer in frame %d not implemented.\n",
 256                                 gtdt_frame->frame_number);
 257                }
 258
 259                frame->cntbase = gtdt_frame->base_address;
 260                /*
 261                 * The CNTBaseN frame is 4KB (register offsets 0x000 - 0xFFC).
 262                 * See ARM DDI 0487A.k_iss10775, page I1-5130, Table I1-4
 263                 * "CNTBaseN memory map".
 264                 */
 265                frame->size = SZ_4K;
 266                frame->valid = true;
 267        }
 268
 269        return 0;
 270
 271error:
 272        do {
 273                if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER ||
 274                    gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES)
 275                        continue;
 276
 277                frame = &timer_mem->frame[gtdt_frame->frame_number];
 278
 279                if (frame->phys_irq > 0)
 280                        acpi_unregister_gsi(gtdt_frame->timer_interrupt);
 281                frame->phys_irq = 0;
 282
 283                if (frame->virt_irq > 0)
 284                        acpi_unregister_gsi(gtdt_frame->virtual_timer_interrupt);
 285                frame->virt_irq = 0;
 286        } while (i-- >= 0 && gtdt_frame--);
 287
 288        return -EINVAL;
 289}
 290
 291/**
 292 * acpi_arch_timer_mem_init() - Get the info of all GT blocks in GTDT table.
 293 * @timer_mem:  The pointer to the array of struct arch_timer_mem for returning
 294 *              the result of parsing. The element number of this array should
 295 *              be platform_timer_count(the total number of platform timers).
 296 * @timer_count: It points to a integer variable which is used for storing the
 297 *              number of GT blocks we have parsed.
 298 *
 299 * Return: 0 if success, -EINVAL/-ENODEV if error.
 300 */
 301int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,
 302                                    int *timer_count)
 303{
 304        int ret;
 305        void *platform_timer;
 306
 307        *timer_count = 0;
 308        for_each_platform_timer(platform_timer) {
 309                if (is_timer_block(platform_timer)) {
 310                        ret = gtdt_parse_timer_block(platform_timer, timer_mem);
 311                        if (ret)
 312                                return ret;
 313                        timer_mem++;
 314                        (*timer_count)++;
 315                }
 316        }
 317
 318        if (*timer_count)
 319                pr_info("found %d memory-mapped timer block(s).\n",
 320                        *timer_count);
 321
 322        return 0;
 323}
 324
 325/*
 326 * Initialize a SBSA generic Watchdog platform device info from GTDT
 327 */
 328static int __init gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,
 329                                        int index)
 330{
 331        struct platform_device *pdev;
 332        int irq;
 333
 334        /*
 335         * According to SBSA specification the size of refresh and control
 336         * frames of SBSA Generic Watchdog is SZ_4K(Offset 0x000 \xE2\x80\x93 0xFFF).
 337         */
 338        struct resource res[] = {
 339                DEFINE_RES_MEM(wd->control_frame_address, SZ_4K),
 340                DEFINE_RES_MEM(wd->refresh_frame_address, SZ_4K),
 341                {},
 342        };
 343        int nr_res = ARRAY_SIZE(res);
 344
 345        pr_debug("found a Watchdog (0x%llx/0x%llx gsi:%u flags:0x%x).\n",
 346                 wd->refresh_frame_address, wd->control_frame_address,
 347                 wd->timer_interrupt, wd->timer_flags);
 348
 349        if (!(wd->refresh_frame_address && wd->control_frame_address)) {
 350                pr_err(FW_BUG "failed to get the Watchdog base address.\n");
 351                return -EINVAL;
 352        }
 353
 354        irq = map_gt_gsi(wd->timer_interrupt, wd->timer_flags);
 355        res[2] = (struct resource)DEFINE_RES_IRQ(irq);
 356        if (irq <= 0) {
 357                pr_warn("failed to map the Watchdog interrupt.\n");
 358                nr_res--;
 359        }
 360
 361        /*
 362         * Add a platform device named "sbsa-gwdt" to match the platform driver.
 363         * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog
 364         * The platform driver can get device info below by matching this name.
 365         */
 366        pdev = platform_device_register_simple("sbsa-gwdt", index, res, nr_res);
 367        if (IS_ERR(pdev)) {
 368                if (irq > 0)
 369                        acpi_unregister_gsi(wd->timer_interrupt);
 370                return PTR_ERR(pdev);
 371        }
 372
 373        return 0;
 374}
 375
 376static int __init gtdt_sbsa_gwdt_init(void)
 377{
 378        void *platform_timer;
 379        struct acpi_table_header *table;
 380        int ret, timer_count, gwdt_count = 0;
 381
 382        if (acpi_disabled)
 383                return 0;
 384
 385        if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table)))
 386                return -EINVAL;
 387
 388        /*
 389         * Note: Even though the global variable acpi_gtdt_desc has been
 390         * initialized by acpi_gtdt_init() while initializing the arch timers,
 391         * when we call this function to get SBSA watchdogs info from GTDT, the
 392         * pointers stashed in it are stale (since they are early temporary
 393         * mappings carried out before acpi_permanent_mmap is set) and we need
 394         * to re-initialize them with permanent mapped pointer values to let the
 395         * GTDT parsing possible.
 396         */
 397        ret = acpi_gtdt_init(table, &timer_count);
 398        if (ret || !timer_count)
 399                goto out_put_gtdt;
 400
 401        for_each_platform_timer(platform_timer) {
 402                if (is_non_secure_watchdog(platform_timer)) {
 403                        ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count);
 404                        if (ret)
 405                                break;
 406                        gwdt_count++;
 407                }
 408        }
 409
 410        if (gwdt_count)
 411                pr_info("found %d SBSA generic Watchdog(s).\n", gwdt_count);
 412
 413out_put_gtdt:
 414        acpi_put_table(table);
 415        return ret;
 416}
 417
 418device_initcall(gtdt_sbsa_gwdt_init);
 419