James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Bus driver for MIPS Common Device Memory Map (CDMM). |
| 3 | * |
| 4 | * Copyright (C) 2014-2015 Imagination Technologies Ltd. |
| 5 | * |
| 6 | * This file is subject to the terms and conditions of the GNU General Public |
| 7 | * License. See the file "COPYING" in the main directory of this archive |
| 8 | * for more details. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/atomic.h> |
| 12 | #include <linux/err.h> |
| 13 | #include <linux/cpu.h> |
| 14 | #include <linux/cpumask.h> |
| 15 | #include <linux/io.h> |
| 16 | #include <linux/platform_device.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/smp.h> |
| 19 | #include <asm/cdmm.h> |
| 20 | #include <asm/hazards.h> |
| 21 | #include <asm/mipsregs.h> |
| 22 | |
| 23 | /* Access control and status register fields */ |
| 24 | #define CDMM_ACSR_DEVTYPE_SHIFT 24 |
| 25 | #define CDMM_ACSR_DEVTYPE (255ul << CDMM_ACSR_DEVTYPE_SHIFT) |
| 26 | #define CDMM_ACSR_DEVSIZE_SHIFT 16 |
| 27 | #define CDMM_ACSR_DEVSIZE (31ul << CDMM_ACSR_DEVSIZE_SHIFT) |
| 28 | #define CDMM_ACSR_DEVREV_SHIFT 12 |
| 29 | #define CDMM_ACSR_DEVREV (15ul << CDMM_ACSR_DEVREV_SHIFT) |
| 30 | #define CDMM_ACSR_UW (1ul << 3) |
| 31 | #define CDMM_ACSR_UR (1ul << 2) |
| 32 | #define CDMM_ACSR_SW (1ul << 1) |
| 33 | #define CDMM_ACSR_SR (1ul << 0) |
| 34 | |
| 35 | /* Each block of device registers is 64 bytes */ |
| 36 | #define CDMM_DRB_SIZE 64 |
| 37 | |
| 38 | #define to_mips_cdmm_driver(d) container_of(d, struct mips_cdmm_driver, drv) |
| 39 | |
| 40 | /* Default physical base address */ |
| 41 | static phys_addr_t mips_cdmm_default_base; |
| 42 | |
| 43 | /* Bus operations */ |
| 44 | |
| 45 | static const struct mips_cdmm_device_id * |
| 46 | mips_cdmm_lookup(const struct mips_cdmm_device_id *table, |
| 47 | struct mips_cdmm_device *dev) |
| 48 | { |
| 49 | int ret = 0; |
| 50 | |
| 51 | for (; table->type; ++table) { |
| 52 | ret = (dev->type == table->type); |
| 53 | if (ret) |
| 54 | break; |
| 55 | } |
| 56 | |
| 57 | return ret ? table : NULL; |
| 58 | } |
| 59 | |
| 60 | static int mips_cdmm_match(struct device *dev, struct device_driver *drv) |
| 61 | { |
| 62 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
| 63 | struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(drv); |
| 64 | |
| 65 | return mips_cdmm_lookup(cdrv->id_table, cdev) != NULL; |
| 66 | } |
| 67 | |
| 68 | static int mips_cdmm_uevent(struct device *dev, struct kobj_uevent_env *env) |
| 69 | { |
| 70 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
| 71 | int retval = 0; |
| 72 | |
| 73 | retval = add_uevent_var(env, "CDMM_CPU=%u", cdev->cpu); |
| 74 | if (retval) |
| 75 | return retval; |
| 76 | |
| 77 | retval = add_uevent_var(env, "CDMM_TYPE=0x%02x", cdev->type); |
| 78 | if (retval) |
| 79 | return retval; |
| 80 | |
| 81 | retval = add_uevent_var(env, "CDMM_REV=%u", cdev->rev); |
| 82 | if (retval) |
| 83 | return retval; |
| 84 | |
| 85 | retval = add_uevent_var(env, "MODALIAS=mipscdmm:t%02X", cdev->type); |
| 86 | return retval; |
| 87 | } |
| 88 | |
| 89 | /* Device attributes */ |
| 90 | |
| 91 | #define CDMM_ATTR(name, fmt, arg...) \ |
| 92 | static ssize_t name##_show(struct device *_dev, \ |
| 93 | struct device_attribute *attr, char *buf) \ |
| 94 | { \ |
| 95 | struct mips_cdmm_device *dev = to_mips_cdmm_device(_dev); \ |
| 96 | return sprintf(buf, fmt, arg); \ |
| 97 | } \ |
| 98 | static DEVICE_ATTR_RO(name); |
| 99 | |
| 100 | CDMM_ATTR(cpu, "%u\n", dev->cpu); |
| 101 | CDMM_ATTR(type, "0x%02x\n", dev->type); |
| 102 | CDMM_ATTR(revision, "%u\n", dev->rev); |
| 103 | CDMM_ATTR(modalias, "mipscdmm:t%02X\n", dev->type); |
| 104 | CDMM_ATTR(resource, "\t%016llx\t%016llx\t%016lx\n", |
| 105 | (unsigned long long)dev->res.start, |
| 106 | (unsigned long long)dev->res.end, |
| 107 | dev->res.flags); |
| 108 | |
| 109 | static struct attribute *mips_cdmm_dev_attrs[] = { |
| 110 | &dev_attr_cpu.attr, |
| 111 | &dev_attr_type.attr, |
| 112 | &dev_attr_revision.attr, |
| 113 | &dev_attr_modalias.attr, |
| 114 | &dev_attr_resource.attr, |
| 115 | NULL, |
| 116 | }; |
| 117 | ATTRIBUTE_GROUPS(mips_cdmm_dev); |
| 118 | |
| 119 | struct bus_type mips_cdmm_bustype = { |
| 120 | .name = "cdmm", |
| 121 | .dev_groups = mips_cdmm_dev_groups, |
| 122 | .match = mips_cdmm_match, |
| 123 | .uevent = mips_cdmm_uevent, |
| 124 | }; |
| 125 | EXPORT_SYMBOL_GPL(mips_cdmm_bustype); |
| 126 | |
| 127 | /* |
| 128 | * Standard driver callback helpers. |
| 129 | * |
| 130 | * All the CDMM driver callbacks need to be executed on the appropriate CPU from |
| 131 | * workqueues. For the standard driver callbacks we need a work function |
| 132 | * (mips_cdmm_{void,int}_work()) to do the actual call from the right CPU, and a |
| 133 | * wrapper function (generated with BUILD_PERCPU_HELPER) to arrange for the work |
| 134 | * function to be called on that CPU. |
| 135 | */ |
| 136 | |
| 137 | /** |
| 138 | * struct mips_cdmm_work_dev - Data for per-device call work. |
| 139 | * @fn: CDMM driver callback function to call for the device. |
| 140 | * @dev: CDMM device to pass to @fn. |
| 141 | */ |
| 142 | struct mips_cdmm_work_dev { |
| 143 | void *fn; |
| 144 | struct mips_cdmm_device *dev; |
| 145 | }; |
| 146 | |
| 147 | /** |
| 148 | * mips_cdmm_void_work() - Call a void returning CDMM driver callback. |
| 149 | * @data: struct mips_cdmm_work_dev pointer. |
| 150 | * |
| 151 | * A work_on_cpu() callback function to call an arbitrary CDMM driver callback |
| 152 | * function which doesn't return a value. |
| 153 | */ |
| 154 | static long mips_cdmm_void_work(void *data) |
| 155 | { |
| 156 | struct mips_cdmm_work_dev *work = data; |
| 157 | void (*fn)(struct mips_cdmm_device *) = work->fn; |
| 158 | |
| 159 | fn(work->dev); |
| 160 | return 0; |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * mips_cdmm_int_work() - Call an int returning CDMM driver callback. |
| 165 | * @data: struct mips_cdmm_work_dev pointer. |
| 166 | * |
| 167 | * A work_on_cpu() callback function to call an arbitrary CDMM driver callback |
| 168 | * function which returns an int. |
| 169 | */ |
| 170 | static long mips_cdmm_int_work(void *data) |
| 171 | { |
| 172 | struct mips_cdmm_work_dev *work = data; |
| 173 | int (*fn)(struct mips_cdmm_device *) = work->fn; |
| 174 | |
| 175 | return fn(work->dev); |
| 176 | } |
| 177 | |
| 178 | #define _BUILD_RET_void |
| 179 | #define _BUILD_RET_int return |
| 180 | |
| 181 | /** |
| 182 | * BUILD_PERCPU_HELPER() - Helper to call a CDMM driver callback on right CPU. |
| 183 | * @_ret: Return type (void or int). |
| 184 | * @_name: Name of CDMM driver callback function. |
| 185 | * |
| 186 | * Generates a specific device callback function to call a CDMM driver callback |
| 187 | * function on the appropriate CPU for the device, and if applicable return the |
| 188 | * result. |
| 189 | */ |
| 190 | #define BUILD_PERCPU_HELPER(_ret, _name) \ |
| 191 | static _ret mips_cdmm_##_name(struct device *dev) \ |
| 192 | { \ |
| 193 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \ |
| 194 | struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(dev->driver); \ |
| 195 | struct mips_cdmm_work_dev work = { \ |
| 196 | .fn = cdrv->_name, \ |
| 197 | .dev = cdev, \ |
| 198 | }; \ |
| 199 | \ |
| 200 | _BUILD_RET_##_ret work_on_cpu(cdev->cpu, \ |
| 201 | mips_cdmm_##_ret##_work, &work); \ |
| 202 | } |
| 203 | |
| 204 | /* Driver callback functions */ |
| 205 | BUILD_PERCPU_HELPER(int, probe) /* int mips_cdmm_probe(struct device) */ |
| 206 | BUILD_PERCPU_HELPER(int, remove) /* int mips_cdmm_remove(struct device) */ |
| 207 | BUILD_PERCPU_HELPER(void, shutdown) /* void mips_cdmm_shutdown(struct device) */ |
| 208 | |
| 209 | |
| 210 | /* Driver registration */ |
| 211 | |
| 212 | /** |
| 213 | * mips_cdmm_driver_register() - Register a CDMM driver. |
| 214 | * @drv: CDMM driver information. |
| 215 | * |
| 216 | * Register a CDMM driver with the CDMM subsystem. The driver will be informed |
| 217 | * of matching devices which are discovered. |
| 218 | * |
| 219 | * Returns: 0 on success. |
| 220 | */ |
| 221 | int mips_cdmm_driver_register(struct mips_cdmm_driver *drv) |
| 222 | { |
| 223 | drv->drv.bus = &mips_cdmm_bustype; |
| 224 | |
| 225 | if (drv->probe) |
| 226 | drv->drv.probe = mips_cdmm_probe; |
| 227 | if (drv->remove) |
| 228 | drv->drv.remove = mips_cdmm_remove; |
| 229 | if (drv->shutdown) |
| 230 | drv->drv.shutdown = mips_cdmm_shutdown; |
| 231 | |
| 232 | return driver_register(&drv->drv); |
| 233 | } |
| 234 | EXPORT_SYMBOL_GPL(mips_cdmm_driver_register); |
| 235 | |
| 236 | /** |
| 237 | * mips_cdmm_driver_unregister() - Unregister a CDMM driver. |
| 238 | * @drv: CDMM driver information. |
| 239 | * |
| 240 | * Unregister a CDMM driver from the CDMM subsystem. |
| 241 | */ |
| 242 | void mips_cdmm_driver_unregister(struct mips_cdmm_driver *drv) |
| 243 | { |
| 244 | driver_unregister(&drv->drv); |
| 245 | } |
| 246 | EXPORT_SYMBOL_GPL(mips_cdmm_driver_unregister); |
| 247 | |
| 248 | |
| 249 | /* CDMM initialisation and bus discovery */ |
| 250 | |
| 251 | /** |
| 252 | * struct mips_cdmm_bus - Info about CDMM bus. |
| 253 | * @phys: Physical address at which it is mapped. |
| 254 | * @regs: Virtual address where registers can be accessed. |
| 255 | * @drbs: Total number of DRBs. |
| 256 | * @drbs_reserved: Number of DRBs reserved. |
| 257 | * @discovered: Whether the devices on the bus have been discovered yet. |
| 258 | * @offline: Whether the CDMM bus is going offline (or very early |
| 259 | * coming back online), in which case it should be |
| 260 | * reconfigured each time. |
| 261 | */ |
| 262 | struct mips_cdmm_bus { |
| 263 | phys_addr_t phys; |
| 264 | void __iomem *regs; |
| 265 | unsigned int drbs; |
| 266 | unsigned int drbs_reserved; |
| 267 | bool discovered; |
| 268 | bool offline; |
| 269 | }; |
| 270 | |
| 271 | static struct mips_cdmm_bus mips_cdmm_boot_bus; |
| 272 | static DEFINE_PER_CPU(struct mips_cdmm_bus *, mips_cdmm_buses); |
| 273 | static atomic_t mips_cdmm_next_id = ATOMIC_INIT(-1); |
| 274 | |
| 275 | /** |
| 276 | * mips_cdmm_get_bus() - Get the per-CPU CDMM bus information. |
| 277 | * |
| 278 | * Get information about the per-CPU CDMM bus, if the bus is present. |
| 279 | * |
| 280 | * The caller must prevent migration to another CPU, either by disabling |
| 281 | * pre-emption or by running from a pinned kernel thread. |
| 282 | * |
| 283 | * Returns: Pointer to CDMM bus information for the current CPU. |
| 284 | * May return ERR_PTR(-errno) in case of error, so check with |
| 285 | * IS_ERR(). |
| 286 | */ |
| 287 | static struct mips_cdmm_bus *mips_cdmm_get_bus(void) |
| 288 | { |
| 289 | struct mips_cdmm_bus *bus, **bus_p; |
| 290 | unsigned long flags; |
| 291 | unsigned int cpu; |
| 292 | |
| 293 | if (!cpu_has_cdmm) |
| 294 | return ERR_PTR(-ENODEV); |
| 295 | |
| 296 | cpu = smp_processor_id(); |
| 297 | /* Avoid early use of per-cpu primitives before initialised */ |
| 298 | if (cpu == 0) |
| 299 | return &mips_cdmm_boot_bus; |
| 300 | |
| 301 | /* Get bus pointer */ |
| 302 | bus_p = per_cpu_ptr(&mips_cdmm_buses, cpu); |
| 303 | local_irq_save(flags); |
| 304 | bus = *bus_p; |
| 305 | /* Attempt allocation if NULL */ |
| 306 | if (unlikely(!bus)) { |
| 307 | bus = kzalloc(sizeof(*bus), GFP_ATOMIC); |
| 308 | if (unlikely(!bus)) |
| 309 | bus = ERR_PTR(-ENOMEM); |
| 310 | else |
| 311 | *bus_p = bus; |
| 312 | } |
| 313 | local_irq_restore(flags); |
| 314 | return bus; |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * mips_cdmm_cur_base() - Find current physical base address of CDMM region. |
| 319 | * |
| 320 | * Returns: Physical base address of CDMM region according to cdmmbase CP0 |
| 321 | * register, or 0 if the CDMM region is disabled. |
| 322 | */ |
| 323 | static phys_addr_t mips_cdmm_cur_base(void) |
| 324 | { |
| 325 | unsigned long cdmmbase = read_c0_cdmmbase(); |
| 326 | |
| 327 | if (!(cdmmbase & MIPS_CDMMBASE_EN)) |
| 328 | return 0; |
| 329 | |
| 330 | return (cdmmbase >> MIPS_CDMMBASE_ADDR_SHIFT) |
| 331 | << MIPS_CDMMBASE_ADDR_START; |
| 332 | } |
| 333 | |
| 334 | /** |
Bjorn Helgaas | e1d9749 | 2015-07-12 18:11:54 -0500 | [diff] [blame] | 335 | * mips_cdmm_phys_base() - Choose a physical base address for CDMM region. |
| 336 | * |
| 337 | * Picking a suitable physical address at which to map the CDMM region is |
| 338 | * platform specific, so this weak function can be overridden by platform |
| 339 | * code to pick a suitable value if none is configured by the bootloader. |
| 340 | */ |
| 341 | phys_addr_t __weak mips_cdmm_phys_base(void) |
| 342 | { |
| 343 | return 0; |
| 344 | } |
| 345 | |
| 346 | /** |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 347 | * mips_cdmm_setup() - Ensure the CDMM bus is initialised and usable. |
| 348 | * @bus: Pointer to bus information for current CPU. |
| 349 | * IS_ERR(bus) is checked, so no need for caller to check. |
| 350 | * |
| 351 | * The caller must prevent migration to another CPU, either by disabling |
| 352 | * pre-emption or by running from a pinned kernel thread. |
| 353 | * |
| 354 | * Returns 0 on success, -errno on failure. |
| 355 | */ |
| 356 | static int mips_cdmm_setup(struct mips_cdmm_bus *bus) |
| 357 | { |
| 358 | unsigned long cdmmbase, flags; |
| 359 | int ret = 0; |
| 360 | |
| 361 | if (IS_ERR(bus)) |
| 362 | return PTR_ERR(bus); |
| 363 | |
| 364 | local_irq_save(flags); |
| 365 | /* Don't set up bus a second time unless marked offline */ |
| 366 | if (bus->offline) { |
| 367 | /* If CDMM region is still set up, nothing to do */ |
| 368 | if (bus->phys == mips_cdmm_cur_base()) |
| 369 | goto out; |
| 370 | /* |
| 371 | * The CDMM region isn't set up as expected, so it needs |
| 372 | * reconfiguring, but then we can stop checking it. |
| 373 | */ |
| 374 | bus->offline = false; |
| 375 | } else if (bus->phys > 1) { |
| 376 | goto out; |
| 377 | } |
| 378 | |
| 379 | /* If the CDMM region is already configured, inherit that setup */ |
| 380 | if (!bus->phys) |
| 381 | bus->phys = mips_cdmm_cur_base(); |
| 382 | /* Otherwise, ask platform code for suggestions */ |
Bjorn Helgaas | e1d9749 | 2015-07-12 18:11:54 -0500 | [diff] [blame] | 383 | if (!bus->phys) |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 384 | bus->phys = mips_cdmm_phys_base(); |
| 385 | /* Otherwise, copy what other CPUs have done */ |
| 386 | if (!bus->phys) |
| 387 | bus->phys = mips_cdmm_default_base; |
| 388 | /* Otherwise, complain once */ |
| 389 | if (!bus->phys) { |
| 390 | bus->phys = 1; |
| 391 | /* |
| 392 | * If you hit this, either your bootloader needs to set up the |
| 393 | * CDMM on the boot CPU, or else you need to implement |
| 394 | * mips_cdmm_phys_base() for your platform (see asm/cdmm.h). |
| 395 | */ |
| 396 | pr_err("cdmm%u: Failed to choose a physical base\n", |
| 397 | smp_processor_id()); |
| 398 | } |
| 399 | /* Already complained? */ |
| 400 | if (bus->phys == 1) { |
| 401 | ret = -ENOMEM; |
| 402 | goto out; |
| 403 | } |
| 404 | /* Record our success for other CPUs to copy */ |
| 405 | mips_cdmm_default_base = bus->phys; |
| 406 | |
| 407 | pr_debug("cdmm%u: Enabling CDMM region at %pa\n", |
| 408 | smp_processor_id(), &bus->phys); |
| 409 | |
| 410 | /* Enable CDMM */ |
| 411 | cdmmbase = read_c0_cdmmbase(); |
| 412 | cdmmbase &= (1ul << MIPS_CDMMBASE_ADDR_SHIFT) - 1; |
| 413 | cdmmbase |= (bus->phys >> MIPS_CDMMBASE_ADDR_START) |
| 414 | << MIPS_CDMMBASE_ADDR_SHIFT; |
| 415 | cdmmbase |= MIPS_CDMMBASE_EN; |
| 416 | write_c0_cdmmbase(cdmmbase); |
| 417 | tlbw_use_hazard(); |
| 418 | |
| 419 | bus->regs = (void __iomem *)CKSEG1ADDR(bus->phys); |
| 420 | bus->drbs = 1 + ((cdmmbase & MIPS_CDMMBASE_SIZE) >> |
| 421 | MIPS_CDMMBASE_SIZE_SHIFT); |
| 422 | bus->drbs_reserved = !!(cdmmbase & MIPS_CDMMBASE_CI); |
| 423 | |
| 424 | out: |
| 425 | local_irq_restore(flags); |
| 426 | return ret; |
| 427 | } |
| 428 | |
| 429 | /** |
| 430 | * mips_cdmm_early_probe() - Minimally probe for a specific device on CDMM. |
| 431 | * @dev_type: CDMM type code to look for. |
| 432 | * |
| 433 | * Minimally configure the in-CPU Common Device Memory Map (CDMM) and look for a |
| 434 | * specific device. This can be used to find a device very early in boot for |
| 435 | * example to configure an early FDC console device. |
| 436 | * |
| 437 | * The caller must prevent migration to another CPU, either by disabling |
| 438 | * pre-emption or by running from a pinned kernel thread. |
| 439 | * |
| 440 | * Returns: MMIO pointer to device memory. The caller can read the ACSR |
| 441 | * register to find more information about the device (such as the |
| 442 | * version number or the number of blocks). |
| 443 | * May return IOMEM_ERR_PTR(-errno) in case of error, so check with |
| 444 | * IS_ERR(). |
| 445 | */ |
| 446 | void __iomem *mips_cdmm_early_probe(unsigned int dev_type) |
| 447 | { |
| 448 | struct mips_cdmm_bus *bus; |
| 449 | void __iomem *cdmm; |
| 450 | u32 acsr; |
| 451 | unsigned int drb, type, size; |
| 452 | int err; |
| 453 | |
| 454 | if (WARN_ON(!dev_type)) |
| 455 | return IOMEM_ERR_PTR(-ENODEV); |
| 456 | |
| 457 | bus = mips_cdmm_get_bus(); |
| 458 | err = mips_cdmm_setup(bus); |
| 459 | if (err) |
| 460 | return IOMEM_ERR_PTR(err); |
| 461 | |
| 462 | /* Skip the first block if it's reserved for more registers */ |
| 463 | drb = bus->drbs_reserved; |
| 464 | cdmm = bus->regs; |
| 465 | |
| 466 | /* Look for a specific device type */ |
| 467 | for (; drb < bus->drbs; drb += size + 1) { |
James Hogan | e21422d | 2015-04-28 10:57:29 +0100 | [diff] [blame] | 468 | acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE); |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 469 | type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT; |
| 470 | if (type == dev_type) |
| 471 | return cdmm + drb * CDMM_DRB_SIZE; |
| 472 | size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT; |
| 473 | } |
| 474 | |
| 475 | return IOMEM_ERR_PTR(-ENODEV); |
| 476 | } |
| 477 | EXPORT_SYMBOL_GPL(mips_cdmm_early_probe); |
| 478 | |
| 479 | /** |
| 480 | * mips_cdmm_release() - Release a removed CDMM device. |
| 481 | * @dev: Device object |
| 482 | * |
| 483 | * Clean up the struct mips_cdmm_device for an unused CDMM device. This is |
| 484 | * called automatically by the driver core when a device is removed. |
| 485 | */ |
| 486 | static void mips_cdmm_release(struct device *dev) |
| 487 | { |
| 488 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
| 489 | |
| 490 | kfree(cdev); |
| 491 | } |
| 492 | |
| 493 | /** |
| 494 | * mips_cdmm_bus_discover() - Discover the devices on the CDMM bus. |
| 495 | * @bus: CDMM bus information, must already be set up. |
| 496 | */ |
| 497 | static void mips_cdmm_bus_discover(struct mips_cdmm_bus *bus) |
| 498 | { |
| 499 | void __iomem *cdmm; |
| 500 | u32 acsr; |
| 501 | unsigned int drb, type, size, rev; |
| 502 | struct mips_cdmm_device *dev; |
| 503 | unsigned int cpu = smp_processor_id(); |
| 504 | int ret = 0; |
| 505 | int id = 0; |
| 506 | |
| 507 | /* Skip the first block if it's reserved for more registers */ |
| 508 | drb = bus->drbs_reserved; |
| 509 | cdmm = bus->regs; |
| 510 | |
| 511 | /* Discover devices */ |
| 512 | bus->discovered = true; |
| 513 | pr_info("cdmm%u discovery (%u blocks)\n", cpu, bus->drbs); |
| 514 | for (; drb < bus->drbs; drb += size + 1) { |
James Hogan | e21422d | 2015-04-28 10:57:29 +0100 | [diff] [blame] | 515 | acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE); |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 516 | type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT; |
| 517 | size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT; |
| 518 | rev = (acsr & CDMM_ACSR_DEVREV) >> CDMM_ACSR_DEVREV_SHIFT; |
| 519 | |
| 520 | if (!type) |
| 521 | continue; |
| 522 | |
| 523 | pr_info("cdmm%u-%u: @%u (%#x..%#x), type 0x%02x, rev %u\n", |
| 524 | cpu, id, drb, drb * CDMM_DRB_SIZE, |
| 525 | (drb + size + 1) * CDMM_DRB_SIZE - 1, |
| 526 | type, rev); |
| 527 | |
| 528 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); |
| 529 | if (!dev) |
| 530 | break; |
| 531 | |
| 532 | dev->cpu = cpu; |
| 533 | dev->res.start = bus->phys + drb * CDMM_DRB_SIZE; |
| 534 | dev->res.end = bus->phys + |
| 535 | (drb + size + 1) * CDMM_DRB_SIZE - 1; |
| 536 | dev->res.flags = IORESOURCE_MEM; |
| 537 | dev->type = type; |
| 538 | dev->rev = rev; |
| 539 | dev->dev.parent = get_cpu_device(cpu); |
| 540 | dev->dev.bus = &mips_cdmm_bustype; |
| 541 | dev->dev.id = atomic_inc_return(&mips_cdmm_next_id); |
| 542 | dev->dev.release = mips_cdmm_release; |
| 543 | |
| 544 | dev_set_name(&dev->dev, "cdmm%u-%u", cpu, id); |
| 545 | ++id; |
| 546 | ret = device_register(&dev->dev); |
| 547 | if (ret) { |
| 548 | put_device(&dev->dev); |
| 549 | kfree(dev); |
| 550 | } |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | |
| 555 | /* |
| 556 | * CPU hotplug and initialisation |
| 557 | * |
| 558 | * All the CDMM driver callbacks need to be executed on the appropriate CPU from |
| 559 | * workqueues. For the CPU callbacks, they need to be called for all devices on |
| 560 | * that CPU, so the work function calls bus_for_each_dev, using a helper |
| 561 | * (generated with BUILD_PERDEV_HELPER) to call the driver callback if the |
| 562 | * device's CPU matches. |
| 563 | */ |
| 564 | |
| 565 | /** |
| 566 | * BUILD_PERDEV_HELPER() - Helper to call a CDMM driver callback if CPU matches. |
| 567 | * @_name: Name of CDMM driver callback function. |
| 568 | * |
| 569 | * Generates a bus_for_each_dev callback function to call a specific CDMM driver |
| 570 | * callback function for the device if the device's CPU matches that pointed to |
| 571 | * by the data argument. |
| 572 | * |
| 573 | * This is used for informing drivers for all devices on a given CPU of some |
| 574 | * event (such as the CPU going online/offline). |
| 575 | * |
| 576 | * It is expected to already be called from the appropriate CPU. |
| 577 | */ |
| 578 | #define BUILD_PERDEV_HELPER(_name) \ |
| 579 | static int mips_cdmm_##_name##_helper(struct device *dev, void *data) \ |
| 580 | { \ |
| 581 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \ |
| 582 | struct mips_cdmm_driver *cdrv; \ |
| 583 | unsigned int cpu = *(unsigned int *)data; \ |
| 584 | \ |
| 585 | if (cdev->cpu != cpu || !dev->driver) \ |
| 586 | return 0; \ |
| 587 | \ |
| 588 | cdrv = to_mips_cdmm_driver(dev->driver); \ |
| 589 | if (!cdrv->_name) \ |
| 590 | return 0; \ |
| 591 | return cdrv->_name(cdev); \ |
| 592 | } |
| 593 | |
| 594 | /* bus_for_each_dev callback helper functions */ |
| 595 | BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */ |
| 596 | BUILD_PERDEV_HELPER(cpu_up) /* int mips_cdmm_cpu_up_helper(...) */ |
| 597 | |
| 598 | /** |
| 599 | * mips_cdmm_bus_down() - Tear down the CDMM bus. |
| 600 | * @data: Pointer to unsigned int CPU number. |
| 601 | * |
Anna-Maria Gleixner | 015aa05 | 2016-05-02 11:00:49 +0200 | [diff] [blame] | 602 | * This function is executed on the hotplugged CPU and calls the CDMM |
| 603 | * driver cpu_down callback for all devices on that CPU. |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 604 | */ |
| 605 | static long mips_cdmm_bus_down(void *data) |
| 606 | { |
| 607 | struct mips_cdmm_bus *bus; |
| 608 | long ret; |
| 609 | |
| 610 | /* Inform all the devices on the bus */ |
| 611 | ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data, |
| 612 | mips_cdmm_cpu_down_helper); |
| 613 | |
| 614 | /* |
| 615 | * While bus is offline, each use of it should reconfigure it just in |
| 616 | * case it is first use when coming back online again. |
| 617 | */ |
| 618 | bus = mips_cdmm_get_bus(); |
| 619 | if (!IS_ERR(bus)) |
| 620 | bus->offline = true; |
| 621 | |
| 622 | return ret; |
| 623 | } |
| 624 | |
| 625 | /** |
| 626 | * mips_cdmm_bus_up() - Bring up the CDMM bus. |
| 627 | * @data: Pointer to unsigned int CPU number. |
| 628 | * |
| 629 | * This work_on_cpu callback function is executed on a given CPU to discover |
| 630 | * CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all |
| 631 | * devices already discovered on that CPU. |
| 632 | * |
Anna-Maria Gleixner | 015aa05 | 2016-05-02 11:00:49 +0200 | [diff] [blame] | 633 | * It is used as work_on_cpu callback function during |
| 634 | * initialisation. When CPUs are brought online the function is |
| 635 | * invoked directly on the hotplugged CPU. |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 636 | */ |
| 637 | static long mips_cdmm_bus_up(void *data) |
| 638 | { |
| 639 | struct mips_cdmm_bus *bus; |
| 640 | long ret; |
| 641 | |
| 642 | bus = mips_cdmm_get_bus(); |
| 643 | ret = mips_cdmm_setup(bus); |
| 644 | if (ret) |
| 645 | return ret; |
| 646 | |
| 647 | /* Bus now set up, so we can drop the offline flag if still set */ |
| 648 | bus->offline = false; |
| 649 | |
| 650 | if (!bus->discovered) |
| 651 | mips_cdmm_bus_discover(bus); |
| 652 | else |
| 653 | /* Inform all the devices on the bus */ |
| 654 | ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data, |
| 655 | mips_cdmm_cpu_up_helper); |
| 656 | |
| 657 | return ret; |
| 658 | } |
| 659 | |
| 660 | /** |
| 661 | * mips_cdmm_cpu_notify() - Take action when a CPU is going online or offline. |
| 662 | * @nb: CPU notifier block . |
| 663 | * @action: Event that has taken place (CPU_*). |
| 664 | * @data: CPU number. |
| 665 | * |
| 666 | * This notifier is used to keep the CDMM buses updated as CPUs are offlined and |
| 667 | * onlined. When CPUs go offline or come back online, so does their CDMM bus, so |
| 668 | * devices must be informed. Also when CPUs come online for the first time the |
| 669 | * devices on the CDMM bus need discovering. |
| 670 | * |
| 671 | * Returns: NOTIFY_OK if event was used. |
| 672 | * NOTIFY_DONE if we didn't care. |
| 673 | */ |
| 674 | static int mips_cdmm_cpu_notify(struct notifier_block *nb, |
| 675 | unsigned long action, void *data) |
| 676 | { |
| 677 | unsigned int cpu = (unsigned int)data; |
| 678 | |
| 679 | switch (action & ~CPU_TASKS_FROZEN) { |
| 680 | case CPU_ONLINE: |
| 681 | case CPU_DOWN_FAILED: |
Anna-Maria Gleixner | 015aa05 | 2016-05-02 11:00:49 +0200 | [diff] [blame] | 682 | mips_cdmm_bus_up(&cpu); |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 683 | break; |
| 684 | case CPU_DOWN_PREPARE: |
Anna-Maria Gleixner | 015aa05 | 2016-05-02 11:00:49 +0200 | [diff] [blame] | 685 | mips_cdmm_bus_down(&cpu); |
James Hogan | 8286ae0 | 2015-03-25 15:39:50 +0000 | [diff] [blame] | 686 | break; |
| 687 | default: |
| 688 | return NOTIFY_DONE; |
| 689 | } |
| 690 | |
| 691 | return NOTIFY_OK; |
| 692 | } |
| 693 | |
| 694 | static struct notifier_block mips_cdmm_cpu_nb = { |
| 695 | .notifier_call = mips_cdmm_cpu_notify, |
| 696 | }; |
| 697 | |
| 698 | /** |
| 699 | * mips_cdmm_init() - Initialise CDMM bus. |
| 700 | * |
| 701 | * Initialise CDMM bus, discover CDMM devices for online CPUs, and arrange for |
| 702 | * hotplug notifications so the CDMM drivers can be kept up to date. |
| 703 | */ |
| 704 | static int __init mips_cdmm_init(void) |
| 705 | { |
| 706 | unsigned int cpu; |
| 707 | int ret; |
| 708 | |
| 709 | /* Register the bus */ |
| 710 | ret = bus_register(&mips_cdmm_bustype); |
| 711 | if (ret) |
| 712 | return ret; |
| 713 | |
| 714 | /* We want to be notified about new CPUs */ |
| 715 | ret = register_cpu_notifier(&mips_cdmm_cpu_nb); |
| 716 | if (ret) { |
| 717 | pr_warn("cdmm: Failed to register CPU notifier\n"); |
| 718 | goto out; |
| 719 | } |
| 720 | |
| 721 | /* Discover devices on CDMM of online CPUs */ |
| 722 | for_each_online_cpu(cpu) |
| 723 | work_on_cpu(cpu, mips_cdmm_bus_up, &cpu); |
| 724 | |
| 725 | return 0; |
| 726 | out: |
| 727 | bus_unregister(&mips_cdmm_bustype); |
| 728 | return ret; |
| 729 | } |
| 730 | subsys_initcall(mips_cdmm_init); |