1 // SPDX-License-Identifier: GPL-2.0
3 // Register cache access API
5 // Copyright 2011 Wolfson Microelectronics plc
9 #include <linux/bsearch.h>
10 #include <linux/device.h>
11 #include <linux/export.h>
12 #include <linux/slab.h>
13 #include <linux/sort.h>
18 static const struct regcache_ops *cache_types[] = {
20 #if IS_ENABLED(CONFIG_REGCACHE_COMPRESSED)
26 static int regcache_hw_init(struct regmap *map)
31 unsigned int reg, val;
34 if (!map->num_reg_defaults_raw)
37 /* calculate the size of reg_defaults */
38 for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++)
39 if (regmap_readable(map, i * map->reg_stride) &&
40 !regmap_volatile(map, i * map->reg_stride))
43 /* all registers are unreadable or volatile, so just bypass */
45 map->cache_bypass = true;
49 map->num_reg_defaults = count;
50 map->reg_defaults = kmalloc_array(count, sizeof(struct reg_default),
52 if (!map->reg_defaults)
55 if (!map->reg_defaults_raw) {
56 bool cache_bypass = map->cache_bypass;
57 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
59 /* Bypass the cache access till data read from HW */
60 map->cache_bypass = true;
61 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
66 ret = regmap_raw_read(map, 0, tmp_buf,
68 map->cache_bypass = cache_bypass;
70 map->reg_defaults_raw = tmp_buf;
77 /* fill the reg_defaults */
78 for (i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
79 reg = i * map->reg_stride;
81 if (!regmap_readable(map, reg))
84 if (regmap_volatile(map, reg))
87 if (map->reg_defaults_raw) {
88 val = regcache_get_val(map, map->reg_defaults_raw, i);
90 bool cache_bypass = map->cache_bypass;
92 map->cache_bypass = true;
93 ret = regmap_read(map, reg, &val);
94 map->cache_bypass = cache_bypass;
96 dev_err(map->dev, "Failed to read %d: %d\n",
102 map->reg_defaults[j].reg = reg;
103 map->reg_defaults[j].def = val;
110 kfree(map->reg_defaults);
115 int regcache_init(struct regmap *map, const struct regmap_config *config)
121 if (map->cache_type == REGCACHE_NONE) {
122 if (config->reg_defaults || config->num_reg_defaults_raw)
124 "No cache used with register defaults set!\n");
126 map->cache_bypass = true;
130 if (config->reg_defaults && !config->num_reg_defaults) {
132 "Register defaults are set without the number!\n");
136 for (i = 0; i < config->num_reg_defaults; i++)
137 if (config->reg_defaults[i].reg % map->reg_stride)
140 for (i = 0; i < ARRAY_SIZE(cache_types); i++)
141 if (cache_types[i]->type == map->cache_type)
144 if (i == ARRAY_SIZE(cache_types)) {
145 dev_err(map->dev, "Could not match compress type: %d\n",
150 map->num_reg_defaults = config->num_reg_defaults;
151 map->num_reg_defaults_raw = config->num_reg_defaults_raw;
152 map->reg_defaults_raw = config->reg_defaults_raw;
153 map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
154 map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
157 map->cache_ops = cache_types[i];
159 if (!map->cache_ops->read ||
160 !map->cache_ops->write ||
161 !map->cache_ops->name)
164 /* We still need to ensure that the reg_defaults
165 * won't vanish from under us. We'll need to make
168 if (config->reg_defaults) {
169 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
170 sizeof(struct reg_default), GFP_KERNEL);
173 map->reg_defaults = tmp_buf;
174 } else if (map->num_reg_defaults_raw) {
175 /* Some devices such as PMICs don't have cache defaults,
176 * we cope with this by reading back the HW registers and
177 * crafting the cache defaults by hand.
179 ret = regcache_hw_init(map);
182 if (map->cache_bypass)
186 if (!map->max_register)
187 map->max_register = map->num_reg_defaults_raw;
189 if (map->cache_ops->init) {
190 dev_dbg(map->dev, "Initializing %s cache\n",
191 map->cache_ops->name);
192 ret = map->cache_ops->init(map);
199 kfree(map->reg_defaults);
201 kfree(map->reg_defaults_raw);
206 void regcache_exit(struct regmap *map)
208 if (map->cache_type == REGCACHE_NONE)
211 BUG_ON(!map->cache_ops);
213 kfree(map->reg_defaults);
215 kfree(map->reg_defaults_raw);
217 if (map->cache_ops->exit) {
218 dev_dbg(map->dev, "Destroying %s cache\n",
219 map->cache_ops->name);
220 map->cache_ops->exit(map);
225 * regcache_read - Fetch the value of a given register from the cache.
227 * @map: map to configure.
228 * @reg: The register index.
229 * @value: The value to be returned.
231 * Return a negative value on failure, 0 on success.
233 int regcache_read(struct regmap *map,
234 unsigned int reg, unsigned int *value)
238 if (map->cache_type == REGCACHE_NONE)
241 BUG_ON(!map->cache_ops);
243 if (!regmap_volatile(map, reg)) {
244 ret = map->cache_ops->read(map, reg, value);
247 trace_regmap_reg_read_cache(map, reg, *value);
256 * regcache_write - Set the value of a given register in the cache.
258 * @map: map to configure.
259 * @reg: The register index.
260 * @value: The new register value.
262 * Return a negative value on failure, 0 on success.
264 int regcache_write(struct regmap *map,
265 unsigned int reg, unsigned int value)
267 if (map->cache_type == REGCACHE_NONE)
270 BUG_ON(!map->cache_ops);
272 if (!regmap_volatile(map, reg))
273 return map->cache_ops->write(map, reg, value);
278 static bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
283 /* If we don't know the chip just got reset, then sync everything. */
284 if (!map->no_sync_defaults)
287 /* Is this the hardware default? If so skip. */
288 ret = regcache_lookup_reg(map, reg);
289 if (ret >= 0 && val == map->reg_defaults[ret].def)
294 static int regcache_default_sync(struct regmap *map, unsigned int min,
299 for (reg = min; reg <= max; reg += map->reg_stride) {
303 if (regmap_volatile(map, reg) ||
304 !regmap_writeable(map, reg))
307 ret = regcache_read(map, reg, &val);
311 if (!regcache_reg_needs_sync(map, reg, val))
314 map->cache_bypass = true;
315 ret = _regmap_write(map, reg, val);
316 map->cache_bypass = false;
318 dev_err(map->dev, "Unable to sync register %#x. %d\n",
322 dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
329 * regcache_sync - Sync the register cache with the hardware.
331 * @map: map to configure.
333 * Any registers that should not be synced should be marked as
334 * volatile. In general drivers can choose not to use the provided
335 * syncing functionality if they so require.
337 * Return a negative value on failure, 0 on success.
339 int regcache_sync(struct regmap *map)
346 BUG_ON(!map->cache_ops);
348 map->lock(map->lock_arg);
349 /* Remember the initial bypass state */
350 bypass = map->cache_bypass;
351 dev_dbg(map->dev, "Syncing %s cache\n",
352 map->cache_ops->name);
353 name = map->cache_ops->name;
354 trace_regcache_sync(map, name, "start");
356 if (!map->cache_dirty)
361 /* Apply any patch first */
362 map->cache_bypass = true;
363 for (i = 0; i < map->patch_regs; i++) {
364 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
366 dev_err(map->dev, "Failed to write %x = %x: %d\n",
367 map->patch[i].reg, map->patch[i].def, ret);
371 map->cache_bypass = false;
373 if (map->cache_ops->sync)
374 ret = map->cache_ops->sync(map, 0, map->max_register);
376 ret = regcache_default_sync(map, 0, map->max_register);
379 map->cache_dirty = false;
382 /* Restore the bypass state */
384 map->cache_bypass = bypass;
385 map->no_sync_defaults = false;
386 map->unlock(map->lock_arg);
388 regmap_async_complete(map);
390 trace_regcache_sync(map, name, "stop");
394 EXPORT_SYMBOL_GPL(regcache_sync);
397 * regcache_sync_region - Sync part of the register cache with the hardware.
400 * @min: first register to sync
401 * @max: last register to sync
403 * Write all non-default register values in the specified region to
406 * Return a negative value on failure, 0 on success.
408 int regcache_sync_region(struct regmap *map, unsigned int min,
415 BUG_ON(!map->cache_ops);
417 map->lock(map->lock_arg);
419 /* Remember the initial bypass state */
420 bypass = map->cache_bypass;
422 name = map->cache_ops->name;
423 dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
425 trace_regcache_sync(map, name, "start region");
427 if (!map->cache_dirty)
432 if (map->cache_ops->sync)
433 ret = map->cache_ops->sync(map, min, max);
435 ret = regcache_default_sync(map, min, max);
438 /* Restore the bypass state */
439 map->cache_bypass = bypass;
441 map->no_sync_defaults = false;
442 map->unlock(map->lock_arg);
444 regmap_async_complete(map);
446 trace_regcache_sync(map, name, "stop region");
450 EXPORT_SYMBOL_GPL(regcache_sync_region);
453 * regcache_drop_region - Discard part of the register cache
455 * @map: map to operate on
456 * @min: first register to discard
457 * @max: last register to discard
459 * Discard part of the register cache.
461 * Return a negative value on failure, 0 on success.
463 int regcache_drop_region(struct regmap *map, unsigned int min,
468 if (!map->cache_ops || !map->cache_ops->drop)
471 map->lock(map->lock_arg);
473 trace_regcache_drop_region(map, min, max);
475 ret = map->cache_ops->drop(map, min, max);
477 map->unlock(map->lock_arg);
481 EXPORT_SYMBOL_GPL(regcache_drop_region);
484 * regcache_cache_only - Put a register map into cache only mode
486 * @map: map to configure
487 * @enable: flag if changes should be written to the hardware
489 * When a register map is marked as cache only writes to the register
490 * map API will only update the register cache, they will not cause
491 * any hardware changes. This is useful for allowing portions of
492 * drivers to act as though the device were functioning as normal when
493 * it is disabled for power saving reasons.
495 void regcache_cache_only(struct regmap *map, bool enable)
497 map->lock(map->lock_arg);
498 WARN_ON(map->cache_bypass && enable);
499 map->cache_only = enable;
500 trace_regmap_cache_only(map, enable);
501 map->unlock(map->lock_arg);
503 EXPORT_SYMBOL_GPL(regcache_cache_only);
506 * regcache_mark_dirty - Indicate that HW registers were reset to default values
510 * Inform regcache that the device has been powered down or reset, so that
511 * on resume, regcache_sync() knows to write out all non-default values
512 * stored in the cache.
514 * If this function is not called, regcache_sync() will assume that
515 * the hardware state still matches the cache state, modulo any writes that
516 * happened when cache_only was true.
518 void regcache_mark_dirty(struct regmap *map)
520 map->lock(map->lock_arg);
521 map->cache_dirty = true;
522 map->no_sync_defaults = true;
523 map->unlock(map->lock_arg);
525 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
528 * regcache_cache_bypass - Put a register map into cache bypass mode
530 * @map: map to configure
531 * @enable: flag if changes should not be written to the cache
533 * When a register map is marked with the cache bypass option, writes
534 * to the register map API will only update the hardware and not the
535 * the cache directly. This is useful when syncing the cache back to
538 void regcache_cache_bypass(struct regmap *map, bool enable)
540 map->lock(map->lock_arg);
541 WARN_ON(map->cache_only && enable);
542 map->cache_bypass = enable;
543 trace_regmap_cache_bypass(map, enable);
544 map->unlock(map->lock_arg);
546 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
548 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
551 if (regcache_get_val(map, base, idx) == val)
554 /* Use device native format if possible */
555 if (map->format.format_val) {
556 map->format.format_val(base + (map->cache_word_size * idx),
561 switch (map->cache_word_size) {
594 unsigned int regcache_get_val(struct regmap *map, const void *base,
600 /* Use device native format if possible */
601 if (map->format.parse_val)
602 return map->format.parse_val(regcache_get_val_addr(map, base,
605 switch (map->cache_word_size) {
607 const u8 *cache = base;
612 const u16 *cache = base;
617 const u32 *cache = base;
623 const u64 *cache = base;
635 static int regcache_default_cmp(const void *a, const void *b)
637 const struct reg_default *_a = a;
638 const struct reg_default *_b = b;
640 return _a->reg - _b->reg;
643 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
645 struct reg_default key;
646 struct reg_default *r;
651 r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
652 sizeof(struct reg_default), regcache_default_cmp);
655 return r - map->reg_defaults;
660 static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
665 return test_bit(idx, cache_present);
668 static int regcache_sync_block_single(struct regmap *map, void *block,
669 unsigned long *cache_present,
670 unsigned int block_base,
671 unsigned int start, unsigned int end)
673 unsigned int i, regtmp, val;
676 for (i = start; i < end; i++) {
677 regtmp = block_base + (i * map->reg_stride);
679 if (!regcache_reg_present(cache_present, i) ||
680 !regmap_writeable(map, regtmp))
683 val = regcache_get_val(map, block, i);
684 if (!regcache_reg_needs_sync(map, regtmp, val))
687 map->cache_bypass = true;
689 ret = _regmap_write(map, regtmp, val);
691 map->cache_bypass = false;
693 dev_err(map->dev, "Unable to sync register %#x. %d\n",
697 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
704 static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
705 unsigned int base, unsigned int cur)
707 size_t val_bytes = map->format.val_bytes;
713 count = (cur - base) / map->reg_stride;
715 dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
716 count * val_bytes, count, base, cur - map->reg_stride);
718 map->cache_bypass = true;
720 ret = _regmap_raw_write(map, base, *data, count * val_bytes);
722 dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
723 base, cur - map->reg_stride, ret);
725 map->cache_bypass = false;
732 static int regcache_sync_block_raw(struct regmap *map, void *block,
733 unsigned long *cache_present,
734 unsigned int block_base, unsigned int start,
738 unsigned int regtmp = 0;
739 unsigned int base = 0;
740 const void *data = NULL;
743 for (i = start; i < end; i++) {
744 regtmp = block_base + (i * map->reg_stride);
746 if (!regcache_reg_present(cache_present, i) ||
747 !regmap_writeable(map, regtmp)) {
748 ret = regcache_sync_block_raw_flush(map, &data,
755 val = regcache_get_val(map, block, i);
756 if (!regcache_reg_needs_sync(map, regtmp, val)) {
757 ret = regcache_sync_block_raw_flush(map, &data,
765 data = regcache_get_val_addr(map, block, i);
770 return regcache_sync_block_raw_flush(map, &data, base, regtmp +
774 int regcache_sync_block(struct regmap *map, void *block,
775 unsigned long *cache_present,
776 unsigned int block_base, unsigned int start,
779 if (regmap_can_raw_write(map) && !map->use_single_write)
780 return regcache_sync_block_raw(map, block, cache_present,
781 block_base, start, end);
783 return regcache_sync_block_single(map, block, cache_present,
784 block_base, start, end);