699 lines · c
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 Public7 * License. See the file "COPYING" in the main directory of this archive8 * 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/of_address.h>17#include <linux/of.h>18#include <linux/platform_device.h>19#include <linux/slab.h>20#include <linux/smp.h>21#include <asm/cdmm.h>22#include <asm/hazards.h>23#include <asm/mipsregs.h>24 25/* Access control and status register fields */26#define CDMM_ACSR_DEVTYPE_SHIFT 2427#define CDMM_ACSR_DEVTYPE (255ul << CDMM_ACSR_DEVTYPE_SHIFT)28#define CDMM_ACSR_DEVSIZE_SHIFT 1629#define CDMM_ACSR_DEVSIZE (31ul << CDMM_ACSR_DEVSIZE_SHIFT)30#define CDMM_ACSR_DEVREV_SHIFT 1231#define CDMM_ACSR_DEVREV (15ul << CDMM_ACSR_DEVREV_SHIFT)32#define CDMM_ACSR_UW (1ul << 3)33#define CDMM_ACSR_UR (1ul << 2)34#define CDMM_ACSR_SW (1ul << 1)35#define CDMM_ACSR_SR (1ul << 0)36 37/* Each block of device registers is 64 bytes */38#define CDMM_DRB_SIZE 6439 40#define to_mips_cdmm_driver(d) container_of_const(d, struct mips_cdmm_driver, drv)41 42/* Default physical base address */43static phys_addr_t mips_cdmm_default_base;44 45/* Bus operations */46 47static const struct mips_cdmm_device_id *48mips_cdmm_lookup(const struct mips_cdmm_device_id *table,49 struct mips_cdmm_device *dev)50{51 int ret = 0;52 53 for (; table->type; ++table) {54 ret = (dev->type == table->type);55 if (ret)56 break;57 }58 59 return ret ? table : NULL;60}61 62static int mips_cdmm_match(struct device *dev, const struct device_driver *drv)63{64 struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);65 const struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(drv);66 67 return mips_cdmm_lookup(cdrv->id_table, cdev) != NULL;68}69 70static int mips_cdmm_uevent(const struct device *dev, struct kobj_uevent_env *env)71{72 const struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);73 int retval = 0;74 75 retval = add_uevent_var(env, "CDMM_CPU=%u", cdev->cpu);76 if (retval)77 return retval;78 79 retval = add_uevent_var(env, "CDMM_TYPE=0x%02x", cdev->type);80 if (retval)81 return retval;82 83 retval = add_uevent_var(env, "CDMM_REV=%u", cdev->rev);84 if (retval)85 return retval;86 87 retval = add_uevent_var(env, "MODALIAS=mipscdmm:t%02X", cdev->type);88 return retval;89}90 91/* Device attributes */92 93#define CDMM_ATTR(name, fmt, arg...) \94static ssize_t name##_show(struct device *_dev, \95 struct device_attribute *attr, char *buf) \96{ \97 struct mips_cdmm_device *dev = to_mips_cdmm_device(_dev); \98 return sprintf(buf, fmt, arg); \99} \100static DEVICE_ATTR_RO(name);101 102CDMM_ATTR(cpu, "%u\n", dev->cpu);103CDMM_ATTR(type, "0x%02x\n", dev->type);104CDMM_ATTR(revision, "%u\n", dev->rev);105CDMM_ATTR(modalias, "mipscdmm:t%02X\n", dev->type);106CDMM_ATTR(resource, "\t%016llx\t%016llx\t%016lx\n",107 (unsigned long long)dev->res.start,108 (unsigned long long)dev->res.end,109 dev->res.flags);110 111static struct attribute *mips_cdmm_dev_attrs[] = {112 &dev_attr_cpu.attr,113 &dev_attr_type.attr,114 &dev_attr_revision.attr,115 &dev_attr_modalias.attr,116 &dev_attr_resource.attr,117 NULL,118};119ATTRIBUTE_GROUPS(mips_cdmm_dev);120 121const struct bus_type mips_cdmm_bustype = {122 .name = "cdmm",123 .dev_groups = mips_cdmm_dev_groups,124 .match = mips_cdmm_match,125 .uevent = mips_cdmm_uevent,126};127EXPORT_SYMBOL_GPL(mips_cdmm_bustype);128 129/*130 * Standard driver callback helpers.131 *132 * All the CDMM driver callbacks need to be executed on the appropriate CPU from133 * workqueues. For the standard driver callbacks we need a work function134 * (mips_cdmm_{void,int}_work()) to do the actual call from the right CPU, and a135 * wrapper function (generated with BUILD_PERCPU_HELPER) to arrange for the work136 * function to be called on that CPU.137 */138 139/**140 * struct mips_cdmm_work_dev - Data for per-device call work.141 * @fn: CDMM driver callback function to call for the device.142 * @dev: CDMM device to pass to @fn.143 */144struct mips_cdmm_work_dev {145 void *fn;146 struct mips_cdmm_device *dev;147};148 149/**150 * mips_cdmm_void_work() - Call a void returning CDMM driver callback.151 * @data: struct mips_cdmm_work_dev pointer.152 *153 * A work_on_cpu() callback function to call an arbitrary CDMM driver callback154 * function which doesn't return a value.155 */156static long mips_cdmm_void_work(void *data)157{158 struct mips_cdmm_work_dev *work = data;159 void (*fn)(struct mips_cdmm_device *) = work->fn;160 161 fn(work->dev);162 return 0;163}164 165/**166 * mips_cdmm_int_work() - Call an int returning CDMM driver callback.167 * @data: struct mips_cdmm_work_dev pointer.168 *169 * A work_on_cpu() callback function to call an arbitrary CDMM driver callback170 * function which returns an int.171 */172static long mips_cdmm_int_work(void *data)173{174 struct mips_cdmm_work_dev *work = data;175 int (*fn)(struct mips_cdmm_device *) = work->fn;176 177 return fn(work->dev);178}179 180#define _BUILD_RET_void181#define _BUILD_RET_int return182 183/**184 * BUILD_PERCPU_HELPER() - Helper to call a CDMM driver callback on right CPU.185 * @_ret: Return type (void or int).186 * @_name: Name of CDMM driver callback function.187 *188 * Generates a specific device callback function to call a CDMM driver callback189 * function on the appropriate CPU for the device, and if applicable return the190 * result.191 */192#define BUILD_PERCPU_HELPER(_ret, _name) \193static _ret mips_cdmm_##_name(struct device *dev) \194{ \195 struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \196 struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(dev->driver); \197 struct mips_cdmm_work_dev work = { \198 .fn = cdrv->_name, \199 .dev = cdev, \200 }; \201 \202 _BUILD_RET_##_ret work_on_cpu(cdev->cpu, \203 mips_cdmm_##_ret##_work, &work); \204}205 206/* Driver callback functions */207BUILD_PERCPU_HELPER(int, probe) /* int mips_cdmm_probe(struct device) */208BUILD_PERCPU_HELPER(int, remove) /* int mips_cdmm_remove(struct device) */209BUILD_PERCPU_HELPER(void, shutdown) /* void mips_cdmm_shutdown(struct device) */210 211 212/* Driver registration */213 214/**215 * mips_cdmm_driver_register() - Register a CDMM driver.216 * @drv: CDMM driver information.217 *218 * Register a CDMM driver with the CDMM subsystem. The driver will be informed219 * of matching devices which are discovered.220 *221 * Returns: 0 on success.222 */223int mips_cdmm_driver_register(struct mips_cdmm_driver *drv)224{225 drv->drv.bus = &mips_cdmm_bustype;226 227 if (drv->probe)228 drv->drv.probe = mips_cdmm_probe;229 if (drv->remove)230 drv->drv.remove = mips_cdmm_remove;231 if (drv->shutdown)232 drv->drv.shutdown = mips_cdmm_shutdown;233 234 return driver_register(&drv->drv);235}236EXPORT_SYMBOL_GPL(mips_cdmm_driver_register);237 238/**239 * mips_cdmm_driver_unregister() - Unregister a CDMM driver.240 * @drv: CDMM driver information.241 *242 * Unregister a CDMM driver from the CDMM subsystem.243 */244void mips_cdmm_driver_unregister(struct mips_cdmm_driver *drv)245{246 driver_unregister(&drv->drv);247}248EXPORT_SYMBOL_GPL(mips_cdmm_driver_unregister);249 250 251/* CDMM initialisation and bus discovery */252 253/**254 * struct mips_cdmm_bus - Info about CDMM bus.255 * @phys: Physical address at which it is mapped.256 * @regs: Virtual address where registers can be accessed.257 * @drbs: Total number of DRBs.258 * @drbs_reserved: Number of DRBs reserved.259 * @discovered: Whether the devices on the bus have been discovered yet.260 * @offline: Whether the CDMM bus is going offline (or very early261 * coming back online), in which case it should be262 * reconfigured each time.263 */264struct mips_cdmm_bus {265 phys_addr_t phys;266 void __iomem *regs;267 unsigned int drbs;268 unsigned int drbs_reserved;269 bool discovered;270 bool offline;271};272 273static struct mips_cdmm_bus mips_cdmm_boot_bus;274static DEFINE_PER_CPU(struct mips_cdmm_bus *, mips_cdmm_buses);275static atomic_t mips_cdmm_next_id = ATOMIC_INIT(-1);276 277/**278 * mips_cdmm_get_bus() - Get the per-CPU CDMM bus information.279 *280 * Get information about the per-CPU CDMM bus, if the bus is present.281 *282 * The caller must prevent migration to another CPU, either by disabling283 * pre-emption or by running from a pinned kernel thread.284 *285 * Returns: Pointer to CDMM bus information for the current CPU.286 * May return ERR_PTR(-errno) in case of error, so check with287 * IS_ERR().288 */289static struct mips_cdmm_bus *mips_cdmm_get_bus(void)290{291 struct mips_cdmm_bus *bus, **bus_p;292 unsigned long flags;293 unsigned int cpu;294 295 if (!cpu_has_cdmm)296 return ERR_PTR(-ENODEV);297 298 cpu = smp_processor_id();299 /* Avoid early use of per-cpu primitives before initialised */300 if (cpu == 0)301 return &mips_cdmm_boot_bus;302 303 /* Get bus pointer */304 bus_p = per_cpu_ptr(&mips_cdmm_buses, cpu);305 local_irq_save(flags);306 bus = *bus_p;307 /* Attempt allocation if NULL */308 if (unlikely(!bus)) {309 bus = kzalloc(sizeof(*bus), GFP_ATOMIC);310 if (unlikely(!bus))311 bus = ERR_PTR(-ENOMEM);312 else313 *bus_p = bus;314 }315 local_irq_restore(flags);316 return bus;317}318 319/**320 * mips_cdmm_cur_base() - Find current physical base address of CDMM region.321 *322 * Returns: Physical base address of CDMM region according to cdmmbase CP0323 * register, or 0 if the CDMM region is disabled.324 */325static phys_addr_t mips_cdmm_cur_base(void)326{327 unsigned long cdmmbase = read_c0_cdmmbase();328 329 if (!(cdmmbase & MIPS_CDMMBASE_EN))330 return 0;331 332 return (cdmmbase >> MIPS_CDMMBASE_ADDR_SHIFT)333 << MIPS_CDMMBASE_ADDR_START;334}335 336/**337 * mips_cdmm_phys_base() - Choose a physical base address for CDMM region.338 *339 * Picking a suitable physical address at which to map the CDMM region is340 * platform specific, so this weak function can be overridden by platform341 * code to pick a suitable value if none is configured by the bootloader.342 * By default this method tries to find a CDMM-specific node in the system343 * dtb. Note that this won't work for early serial console.344 */345phys_addr_t __weak mips_cdmm_phys_base(void)346{347 struct device_node *np;348 struct resource res;349 int err;350 351 np = of_find_compatible_node(NULL, NULL, "mti,mips-cdmm");352 if (np) {353 err = of_address_to_resource(np, 0, &res);354 of_node_put(np);355 if (!err)356 return res.start;357 }358 359 return 0;360}361 362/**363 * mips_cdmm_setup() - Ensure the CDMM bus is initialised and usable.364 * @bus: Pointer to bus information for current CPU.365 * IS_ERR(bus) is checked, so no need for caller to check.366 *367 * The caller must prevent migration to another CPU, either by disabling368 * pre-emption or by running from a pinned kernel thread.369 *370 * Returns 0 on success, -errno on failure.371 */372static int mips_cdmm_setup(struct mips_cdmm_bus *bus)373{374 unsigned long cdmmbase, flags;375 int ret = 0;376 377 if (IS_ERR(bus))378 return PTR_ERR(bus);379 380 local_irq_save(flags);381 /* Don't set up bus a second time unless marked offline */382 if (bus->offline) {383 /* If CDMM region is still set up, nothing to do */384 if (bus->phys == mips_cdmm_cur_base())385 goto out;386 /*387 * The CDMM region isn't set up as expected, so it needs388 * reconfiguring, but then we can stop checking it.389 */390 bus->offline = false;391 } else if (bus->phys > 1) {392 goto out;393 }394 395 /* If the CDMM region is already configured, inherit that setup */396 if (!bus->phys)397 bus->phys = mips_cdmm_cur_base();398 /* Otherwise, ask platform code for suggestions */399 if (!bus->phys)400 bus->phys = mips_cdmm_phys_base();401 /* Otherwise, copy what other CPUs have done */402 if (!bus->phys)403 bus->phys = mips_cdmm_default_base;404 /* Otherwise, complain once */405 if (!bus->phys) {406 bus->phys = 1;407 /*408 * If you hit this, either your bootloader needs to set up the409 * CDMM on the boot CPU, or else you need to implement410 * mips_cdmm_phys_base() for your platform (see asm/cdmm.h).411 */412 pr_err("cdmm%u: Failed to choose a physical base\n",413 smp_processor_id());414 }415 /* Already complained? */416 if (bus->phys == 1) {417 ret = -ENOMEM;418 goto out;419 }420 /* Record our success for other CPUs to copy */421 mips_cdmm_default_base = bus->phys;422 423 pr_debug("cdmm%u: Enabling CDMM region at %pa\n",424 smp_processor_id(), &bus->phys);425 426 /* Enable CDMM */427 cdmmbase = read_c0_cdmmbase();428 cdmmbase &= (1ul << MIPS_CDMMBASE_ADDR_SHIFT) - 1;429 cdmmbase |= (bus->phys >> MIPS_CDMMBASE_ADDR_START)430 << MIPS_CDMMBASE_ADDR_SHIFT;431 cdmmbase |= MIPS_CDMMBASE_EN;432 write_c0_cdmmbase(cdmmbase);433 tlbw_use_hazard();434 435 bus->regs = (void __iomem *)CKSEG1ADDR(bus->phys);436 bus->drbs = 1 + ((cdmmbase & MIPS_CDMMBASE_SIZE) >>437 MIPS_CDMMBASE_SIZE_SHIFT);438 bus->drbs_reserved = !!(cdmmbase & MIPS_CDMMBASE_CI);439 440out:441 local_irq_restore(flags);442 return ret;443}444 445/**446 * mips_cdmm_early_probe() - Minimally probe for a specific device on CDMM.447 * @dev_type: CDMM type code to look for.448 *449 * Minimally configure the in-CPU Common Device Memory Map (CDMM) and look for a450 * specific device. This can be used to find a device very early in boot for451 * example to configure an early FDC console device.452 *453 * The caller must prevent migration to another CPU, either by disabling454 * pre-emption or by running from a pinned kernel thread.455 *456 * Returns: MMIO pointer to device memory. The caller can read the ACSR457 * register to find more information about the device (such as the458 * version number or the number of blocks).459 * May return IOMEM_ERR_PTR(-errno) in case of error, so check with460 * IS_ERR().461 */462void __iomem *mips_cdmm_early_probe(unsigned int dev_type)463{464 struct mips_cdmm_bus *bus;465 void __iomem *cdmm;466 u32 acsr;467 unsigned int drb, type, size;468 int err;469 470 if (WARN_ON(!dev_type))471 return IOMEM_ERR_PTR(-ENODEV);472 473 bus = mips_cdmm_get_bus();474 err = mips_cdmm_setup(bus);475 if (err)476 return IOMEM_ERR_PTR(err);477 478 /* Skip the first block if it's reserved for more registers */479 drb = bus->drbs_reserved;480 cdmm = bus->regs;481 482 /* Look for a specific device type */483 for (; drb < bus->drbs; drb += size + 1) {484 acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE);485 type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT;486 if (type == dev_type)487 return cdmm + drb * CDMM_DRB_SIZE;488 size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT;489 }490 491 return IOMEM_ERR_PTR(-ENODEV);492}493EXPORT_SYMBOL_GPL(mips_cdmm_early_probe);494 495/**496 * mips_cdmm_release() - Release a removed CDMM device.497 * @dev: Device object498 *499 * Clean up the struct mips_cdmm_device for an unused CDMM device. This is500 * called automatically by the driver core when a device is removed.501 */502static void mips_cdmm_release(struct device *dev)503{504 struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev);505 506 kfree(cdev);507}508 509/**510 * mips_cdmm_bus_discover() - Discover the devices on the CDMM bus.511 * @bus: CDMM bus information, must already be set up.512 */513static void mips_cdmm_bus_discover(struct mips_cdmm_bus *bus)514{515 void __iomem *cdmm;516 u32 acsr;517 unsigned int drb, type, size, rev;518 struct mips_cdmm_device *dev;519 unsigned int cpu = smp_processor_id();520 int ret = 0;521 int id = 0;522 523 /* Skip the first block if it's reserved for more registers */524 drb = bus->drbs_reserved;525 cdmm = bus->regs;526 527 /* Discover devices */528 bus->discovered = true;529 pr_info("cdmm%u discovery (%u blocks)\n", cpu, bus->drbs);530 for (; drb < bus->drbs; drb += size + 1) {531 acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE);532 type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT;533 size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT;534 rev = (acsr & CDMM_ACSR_DEVREV) >> CDMM_ACSR_DEVREV_SHIFT;535 536 if (!type)537 continue;538 539 pr_info("cdmm%u-%u: @%u (%#x..%#x), type 0x%02x, rev %u\n",540 cpu, id, drb, drb * CDMM_DRB_SIZE,541 (drb + size + 1) * CDMM_DRB_SIZE - 1,542 type, rev);543 544 dev = kzalloc(sizeof(*dev), GFP_KERNEL);545 if (!dev)546 break;547 548 dev->cpu = cpu;549 dev->res.start = bus->phys + drb * CDMM_DRB_SIZE;550 dev->res.end = bus->phys +551 (drb + size + 1) * CDMM_DRB_SIZE - 1;552 dev->res.flags = IORESOURCE_MEM;553 dev->type = type;554 dev->rev = rev;555 dev->dev.parent = get_cpu_device(cpu);556 dev->dev.bus = &mips_cdmm_bustype;557 dev->dev.id = atomic_inc_return(&mips_cdmm_next_id);558 dev->dev.release = mips_cdmm_release;559 560 dev_set_name(&dev->dev, "cdmm%u-%u", cpu, id);561 ++id;562 ret = device_register(&dev->dev);563 if (ret)564 put_device(&dev->dev);565 }566}567 568 569/*570 * CPU hotplug and initialisation571 *572 * All the CDMM driver callbacks need to be executed on the appropriate CPU from573 * workqueues. For the CPU callbacks, they need to be called for all devices on574 * that CPU, so the work function calls bus_for_each_dev, using a helper575 * (generated with BUILD_PERDEV_HELPER) to call the driver callback if the576 * device's CPU matches.577 */578 579/**580 * BUILD_PERDEV_HELPER() - Helper to call a CDMM driver callback if CPU matches.581 * @_name: Name of CDMM driver callback function.582 *583 * Generates a bus_for_each_dev callback function to call a specific CDMM driver584 * callback function for the device if the device's CPU matches that pointed to585 * by the data argument.586 *587 * This is used for informing drivers for all devices on a given CPU of some588 * event (such as the CPU going online/offline).589 *590 * It is expected to already be called from the appropriate CPU.591 */592#define BUILD_PERDEV_HELPER(_name) \593static int mips_cdmm_##_name##_helper(struct device *dev, void *data) \594{ \595 struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \596 struct mips_cdmm_driver *cdrv; \597 unsigned int cpu = *(unsigned int *)data; \598 \599 if (cdev->cpu != cpu || !dev->driver) \600 return 0; \601 \602 cdrv = to_mips_cdmm_driver(dev->driver); \603 if (!cdrv->_name) \604 return 0; \605 return cdrv->_name(cdev); \606}607 608/* bus_for_each_dev callback helper functions */609BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */610BUILD_PERDEV_HELPER(cpu_up) /* int mips_cdmm_cpu_up_helper(...) */611 612/**613 * mips_cdmm_cpu_down_prep() - Callback for CPUHP DOWN_PREP:614 * Tear down the CDMM bus.615 * @cpu: unsigned int CPU number.616 *617 * This function is executed on the hotplugged CPU and calls the CDMM618 * driver cpu_down callback for all devices on that CPU.619 */620static int mips_cdmm_cpu_down_prep(unsigned int cpu)621{622 struct mips_cdmm_bus *bus;623 long ret;624 625 /* Inform all the devices on the bus */626 ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu,627 mips_cdmm_cpu_down_helper);628 629 /*630 * While bus is offline, each use of it should reconfigure it just in631 * case it is first use when coming back online again.632 */633 bus = mips_cdmm_get_bus();634 if (!IS_ERR(bus))635 bus->offline = true;636 637 return ret;638}639 640/**641 * mips_cdmm_cpu_online() - Callback for CPUHP ONLINE: Bring up the CDMM bus.642 * @cpu: unsigned int CPU number.643 *644 * This work_on_cpu callback function is executed on a given CPU to discover645 * CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all646 * devices already discovered on that CPU.647 *648 * It is used as work_on_cpu callback function during649 * initialisation. When CPUs are brought online the function is650 * invoked directly on the hotplugged CPU.651 */652static int mips_cdmm_cpu_online(unsigned int cpu)653{654 struct mips_cdmm_bus *bus;655 long ret;656 657 bus = mips_cdmm_get_bus();658 ret = mips_cdmm_setup(bus);659 if (ret)660 return ret;661 662 /* Bus now set up, so we can drop the offline flag if still set */663 bus->offline = false;664 665 if (!bus->discovered)666 mips_cdmm_bus_discover(bus);667 else668 /* Inform all the devices on the bus */669 ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu,670 mips_cdmm_cpu_up_helper);671 672 return ret;673}674 675/**676 * mips_cdmm_init() - Initialise CDMM bus.677 *678 * Initialise CDMM bus, discover CDMM devices for online CPUs, and arrange for679 * hotplug notifications so the CDMM drivers can be kept up to date.680 */681static int __init mips_cdmm_init(void)682{683 int ret;684 685 /* Register the bus */686 ret = bus_register(&mips_cdmm_bustype);687 if (ret)688 return ret;689 690 /* We want to be notified about new CPUs */691 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "bus/cdmm:online",692 mips_cdmm_cpu_online, mips_cdmm_cpu_down_prep);693 if (ret < 0)694 pr_warn("cdmm: Failed to register CPU notifier\n");695 696 return ret;697}698subsys_initcall(mips_cdmm_init);699