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/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 24 |
27 | #define CDMM_ACSR_DEVTYPE (255ul << CDMM_ACSR_DEVTYPE_SHIFT) |
28 | #define CDMM_ACSR_DEVSIZE_SHIFT 16 |
29 | #define CDMM_ACSR_DEVSIZE (31ul << CDMM_ACSR_DEVSIZE_SHIFT) |
30 | #define CDMM_ACSR_DEVREV_SHIFT 12 |
31 | #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 64 |
39 | |
40 | #define to_mips_cdmm_driver(d) container_of(d, struct mips_cdmm_driver, drv) |
41 | |
42 | /* Default physical base address */ |
43 | static phys_addr_t mips_cdmm_default_base; |
44 | |
45 | /* Bus operations */ |
46 | |
47 | static const struct mips_cdmm_device_id * |
48 | mips_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 | |
62 | static int mips_cdmm_match(struct device *dev, struct device_driver *drv) |
63 | { |
64 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
65 | struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(drv); |
66 | |
67 | return mips_cdmm_lookup(table: cdrv->id_table, dev: cdev) != NULL; |
68 | } |
69 | |
70 | static 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, format: "CDMM_CPU=%u" , cdev->cpu); |
76 | if (retval) |
77 | return retval; |
78 | |
79 | retval = add_uevent_var(env, format: "CDMM_TYPE=0x%02x" , cdev->type); |
80 | if (retval) |
81 | return retval; |
82 | |
83 | retval = add_uevent_var(env, format: "CDMM_REV=%u" , cdev->rev); |
84 | if (retval) |
85 | return retval; |
86 | |
87 | retval = add_uevent_var(env, format: "MODALIAS=mipscdmm:t%02X" , cdev->type); |
88 | return retval; |
89 | } |
90 | |
91 | /* Device attributes */ |
92 | |
93 | #define CDMM_ATTR(name, fmt, arg...) \ |
94 | static 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 | } \ |
100 | static DEVICE_ATTR_RO(name); |
101 | |
102 | CDMM_ATTR(cpu, "%u\n" , dev->cpu); |
103 | CDMM_ATTR(type, "0x%02x\n" , dev->type); |
104 | CDMM_ATTR(revision, "%u\n" , dev->rev); |
105 | CDMM_ATTR(modalias, "mipscdmm:t%02X\n" , dev->type); |
106 | CDMM_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 | |
111 | static 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 | }; |
119 | ATTRIBUTE_GROUPS(mips_cdmm_dev); |
120 | |
121 | 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 | }; |
127 | EXPORT_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 from |
133 | * workqueues. For the standard driver callbacks we need a work function |
134 | * (mips_cdmm_{void,int}_work()) to do the actual call from the right CPU, and a |
135 | * wrapper function (generated with BUILD_PERCPU_HELPER) to arrange for the work |
136 | * 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 | */ |
144 | struct 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 callback |
154 | * function which doesn't return a value. |
155 | */ |
156 | static 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 callback |
170 | * function which returns an int. |
171 | */ |
172 | static 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_void |
181 | #define _BUILD_RET_int return |
182 | |
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 callback |
189 | * function on the appropriate CPU for the device, and if applicable return the |
190 | * result. |
191 | */ |
192 | #define BUILD_PERCPU_HELPER(_ret, _name) \ |
193 | static _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 */ |
207 | BUILD_PERCPU_HELPER(int, probe) /* int mips_cdmm_probe(struct device) */ |
208 | BUILD_PERCPU_HELPER(int, remove) /* int mips_cdmm_remove(struct device) */ |
209 | BUILD_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 informed |
219 | * of matching devices which are discovered. |
220 | * |
221 | * Returns: 0 on success. |
222 | */ |
223 | int 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->drv); |
235 | } |
236 | EXPORT_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 | */ |
244 | void mips_cdmm_driver_unregister(struct mips_cdmm_driver *drv) |
245 | { |
246 | driver_unregister(drv: &drv->drv); |
247 | } |
248 | EXPORT_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 early |
261 | * coming back online), in which case it should be |
262 | * reconfigured each time. |
263 | */ |
264 | struct 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 | |
273 | static struct mips_cdmm_bus mips_cdmm_boot_bus; |
274 | static DEFINE_PER_CPU(struct mips_cdmm_bus *, mips_cdmm_buses); |
275 | static 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 disabling |
283 | * 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 with |
287 | * IS_ERR(). |
288 | */ |
289 | static 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(error: -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(size: sizeof(*bus), GFP_ATOMIC); |
310 | if (unlikely(!bus)) |
311 | bus = ERR_PTR(error: -ENOMEM); |
312 | else |
313 | *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 CP0 |
323 | * register, or 0 if the CDMM region is disabled. |
324 | */ |
325 | static 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 is |
340 | * platform specific, so this weak function can be overridden by platform |
341 | * 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 system |
343 | * dtb. Note that this won't work for early serial console. |
344 | */ |
345 | phys_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, compat: "mti,mips-cdmm" ); |
352 | if (np) { |
353 | err = of_address_to_resource(dev: np, index: 0, r: &res); |
354 | of_node_put(node: 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 disabling |
368 | * pre-emption or by running from a pinned kernel thread. |
369 | * |
370 | * Returns 0 on success, -errno on failure. |
371 | */ |
372 | static int mips_cdmm_setup(struct mips_cdmm_bus *bus) |
373 | { |
374 | unsigned long cdmmbase, flags; |
375 | int ret = 0; |
376 | |
377 | if (IS_ERR(ptr: bus)) |
378 | return PTR_ERR(ptr: 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 needs |
388 | * 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 the |
409 | * CDMM on the boot CPU, or else you need to implement |
410 | * 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 | |
440 | out: |
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 a |
450 | * specific device. This can be used to find a device very early in boot for |
451 | * example to configure an early FDC console device. |
452 | * |
453 | * The caller must prevent migration to another CPU, either by disabling |
454 | * pre-emption or by running from a pinned kernel thread. |
455 | * |
456 | * Returns: MMIO pointer to device memory. The caller can read the ACSR |
457 | * register to find more information about the device (such as the |
458 | * version number or the number of blocks). |
459 | * May return IOMEM_ERR_PTR(-errno) in case of error, so check with |
460 | * IS_ERR(). |
461 | */ |
462 | void __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(addr: 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 | } |
493 | EXPORT_SYMBOL_GPL(mips_cdmm_early_probe); |
494 | |
495 | /** |
496 | * mips_cdmm_release() - Release a removed CDMM device. |
497 | * @dev: Device object |
498 | * |
499 | * Clean up the struct mips_cdmm_device for an unused CDMM device. This is |
500 | * called automatically by the driver core when a device is removed. |
501 | */ |
502 | static void mips_cdmm_release(struct device *dev) |
503 | { |
504 | struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
505 | |
506 | kfree(objp: 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 | */ |
513 | static 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(addr: 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(v: &mips_cdmm_next_id); |
558 | dev->dev.release = mips_cdmm_release; |
559 | |
560 | dev_set_name(dev: &dev->dev, name: "cdmm%u-%u" , cpu, id); |
561 | ++id; |
562 | ret = device_register(dev: &dev->dev); |
563 | if (ret) |
564 | put_device(dev: &dev->dev); |
565 | } |
566 | } |
567 | |
568 | |
569 | /* |
570 | * CPU hotplug and initialisation |
571 | * |
572 | * All the CDMM driver callbacks need to be executed on the appropriate CPU from |
573 | * workqueues. For the CPU callbacks, they need to be called for all devices on |
574 | * that CPU, so the work function calls bus_for_each_dev, using a helper |
575 | * (generated with BUILD_PERDEV_HELPER) to call the driver callback if the |
576 | * 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 driver |
584 | * callback function for the device if the device's CPU matches that pointed to |
585 | * by the data argument. |
586 | * |
587 | * This is used for informing drivers for all devices on a given CPU of some |
588 | * 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) \ |
593 | static 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 */ |
609 | BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */ |
610 | BUILD_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 CDMM |
618 | * driver cpu_down callback for all devices on that CPU. |
619 | */ |
620 | static 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(bus: &mips_cdmm_bustype, NULL, data: &cpu, |
627 | fn: mips_cdmm_cpu_down_helper); |
628 | |
629 | /* |
630 | * While bus is offline, each use of it should reconfigure it just in |
631 | * case it is first use when coming back online again. |
632 | */ |
633 | bus = mips_cdmm_get_bus(); |
634 | if (!IS_ERR(ptr: 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 discover |
645 | * CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all |
646 | * devices already discovered on that CPU. |
647 | * |
648 | * It is used as work_on_cpu callback function during |
649 | * initialisation. When CPUs are brought online the function is |
650 | * invoked directly on the hotplugged CPU. |
651 | */ |
652 | static 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 | else |
668 | /* Inform all the devices on the bus */ |
669 | ret = bus_for_each_dev(bus: &mips_cdmm_bustype, NULL, data: &cpu, |
670 | fn: 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 for |
679 | * hotplug notifications so the CDMM drivers can be kept up to date. |
680 | */ |
681 | static int __init mips_cdmm_init(void) |
682 | { |
683 | int ret; |
684 | |
685 | /* Register the bus */ |
686 | ret = bus_register(bus: &mips_cdmm_bustype); |
687 | if (ret) |
688 | return ret; |
689 | |
690 | /* We want to be notified about new CPUs */ |
691 | ret = cpuhp_setup_state(state: CPUHP_AP_ONLINE_DYN, name: "bus/cdmm:online" , |
692 | startup: mips_cdmm_cpu_online, teardown: mips_cdmm_cpu_down_prep); |
693 | if (ret < 0) |
694 | pr_warn("cdmm: Failed to register CPU notifier\n" ); |
695 | |
696 | return ret; |
697 | } |
698 | subsys_initcall(mips_cdmm_init); |
699 | |