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;
71 map->cache_free = true;
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 if (config->num_reg_defaults && !config->reg_defaults) {
138 "Register defaults number are set without the reg!\n");
142 for (i = 0; i < config->num_reg_defaults; i++)
143 if (config->reg_defaults[i].reg % map->reg_stride)
146 for (i = 0; i < ARRAY_SIZE(cache_types); i++)
147 if (cache_types[i]->type == map->cache_type)
150 if (i == ARRAY_SIZE(cache_types)) {
151 dev_err(map->dev, "Could not match compress type: %d\n",
156 map->num_reg_defaults = config->num_reg_defaults;
157 map->num_reg_defaults_raw = config->num_reg_defaults_raw;
158 map->reg_defaults_raw = config->reg_defaults_raw;
159 map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
160 map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
163 map->cache_ops = cache_types[i];
165 if (!map->cache_ops->read ||
166 !map->cache_ops->write ||
167 !map->cache_ops->name)
170 /* We still need to ensure that the reg_defaults
171 * won't vanish from under us. We'll need to make
174 if (config->reg_defaults) {
175 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
176 sizeof(struct reg_default), GFP_KERNEL);
179 map->reg_defaults = tmp_buf;
180 } else if (map->num_reg_defaults_raw) {
181 /* Some devices such as PMICs don't have cache defaults,
182 * we cope with this by reading back the HW registers and
183 * crafting the cache defaults by hand.
185 ret = regcache_hw_init(map);
188 if (map->cache_bypass)
192 if (!map->max_register && map->num_reg_defaults_raw)
193 map->max_register = (map->num_reg_defaults_raw - 1) * map->reg_stride;
195 if (map->cache_ops->init) {
196 dev_dbg(map->dev, "Initializing %s cache\n",
197 map->cache_ops->name);
198 ret = map->cache_ops->init(map);
205 kfree(map->reg_defaults);
207 kfree(map->reg_defaults_raw);
212 void regcache_exit(struct regmap *map)
214 if (map->cache_type == REGCACHE_NONE)
217 BUG_ON(!map->cache_ops);
219 kfree(map->reg_defaults);
221 kfree(map->reg_defaults_raw);
223 if (map->cache_ops->exit) {
224 dev_dbg(map->dev, "Destroying %s cache\n",
225 map->cache_ops->name);
226 map->cache_ops->exit(map);
231 * regcache_read - Fetch the value of a given register from the cache.
233 * @map: map to configure.
234 * @reg: The register index.
235 * @value: The value to be returned.
237 * Return a negative value on failure, 0 on success.
239 int regcache_read(struct regmap *map,
240 unsigned int reg, unsigned int *value)
244 if (map->cache_type == REGCACHE_NONE)
247 BUG_ON(!map->cache_ops);
249 if (!regmap_volatile(map, reg)) {
250 ret = map->cache_ops->read(map, reg, value);
253 trace_regmap_reg_read_cache(map, reg, *value);
262 * regcache_write - Set the value of a given register in the cache.
264 * @map: map to configure.
265 * @reg: The register index.
266 * @value: The new register value.
268 * Return a negative value on failure, 0 on success.
270 int regcache_write(struct regmap *map,
271 unsigned int reg, unsigned int value)
273 if (map->cache_type == REGCACHE_NONE)
276 BUG_ON(!map->cache_ops);
278 if (!regmap_volatile(map, reg))
279 return map->cache_ops->write(map, reg, value);
284 static bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
289 /* If we don't know the chip just got reset, then sync everything. */
290 if (!map->no_sync_defaults)
293 /* Is this the hardware default? If so skip. */
294 ret = regcache_lookup_reg(map, reg);
295 if (ret >= 0 && val == map->reg_defaults[ret].def)
300 static int regcache_default_sync(struct regmap *map, unsigned int min,
305 for (reg = min; reg <= max; reg += map->reg_stride) {
309 if (regmap_volatile(map, reg) ||
310 !regmap_writeable(map, reg))
313 ret = regcache_read(map, reg, &val);
317 if (!regcache_reg_needs_sync(map, reg, val))
320 map->cache_bypass = true;
321 ret = _regmap_write(map, reg, val);
322 map->cache_bypass = false;
324 dev_err(map->dev, "Unable to sync register %#x. %d\n",
328 dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
335 * regcache_sync - Sync the register cache with the hardware.
337 * @map: map to configure.
339 * Any registers that should not be synced should be marked as
340 * volatile. In general drivers can choose not to use the provided
341 * syncing functionality if they so require.
343 * Return a negative value on failure, 0 on success.
345 int regcache_sync(struct regmap *map)
352 BUG_ON(!map->cache_ops);
354 map->lock(map->lock_arg);
355 /* Remember the initial bypass state */
356 bypass = map->cache_bypass;
357 dev_dbg(map->dev, "Syncing %s cache\n",
358 map->cache_ops->name);
359 name = map->cache_ops->name;
360 trace_regcache_sync(map, name, "start");
362 if (!map->cache_dirty)
367 /* Apply any patch first */
368 map->cache_bypass = true;
369 for (i = 0; i < map->patch_regs; i++) {
370 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
372 dev_err(map->dev, "Failed to write %x = %x: %d\n",
373 map->patch[i].reg, map->patch[i].def, ret);
377 map->cache_bypass = false;
379 if (map->cache_ops->sync)
380 ret = map->cache_ops->sync(map, 0, map->max_register);
382 ret = regcache_default_sync(map, 0, map->max_register);
385 map->cache_dirty = false;
388 /* Restore the bypass state */
390 map->cache_bypass = bypass;
391 map->no_sync_defaults = false;
392 map->unlock(map->lock_arg);
394 regmap_async_complete(map);
396 trace_regcache_sync(map, name, "stop");
400 EXPORT_SYMBOL_GPL(regcache_sync);
403 * regcache_sync_region - Sync part of the register cache with the hardware.
406 * @min: first register to sync
407 * @max: last register to sync
409 * Write all non-default register values in the specified region to
412 * Return a negative value on failure, 0 on success.
414 int regcache_sync_region(struct regmap *map, unsigned int min,
421 BUG_ON(!map->cache_ops);
423 map->lock(map->lock_arg);
425 /* Remember the initial bypass state */
426 bypass = map->cache_bypass;
428 name = map->cache_ops->name;
429 dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
431 trace_regcache_sync(map, name, "start region");
433 if (!map->cache_dirty)
438 if (map->cache_ops->sync)
439 ret = map->cache_ops->sync(map, min, max);
441 ret = regcache_default_sync(map, min, max);
444 /* Restore the bypass state */
445 map->cache_bypass = bypass;
447 map->no_sync_defaults = false;
448 map->unlock(map->lock_arg);
450 regmap_async_complete(map);
452 trace_regcache_sync(map, name, "stop region");
456 EXPORT_SYMBOL_GPL(regcache_sync_region);
459 * regcache_drop_region - Discard part of the register cache
461 * @map: map to operate on
462 * @min: first register to discard
463 * @max: last register to discard
465 * Discard part of the register cache.
467 * Return a negative value on failure, 0 on success.
469 int regcache_drop_region(struct regmap *map, unsigned int min,
474 if (!map->cache_ops || !map->cache_ops->drop)
477 map->lock(map->lock_arg);
479 trace_regcache_drop_region(map, min, max);
481 ret = map->cache_ops->drop(map, min, max);
483 map->unlock(map->lock_arg);
487 EXPORT_SYMBOL_GPL(regcache_drop_region);
490 * regcache_cache_only - Put a register map into cache only mode
492 * @map: map to configure
493 * @enable: flag if changes should be written to the hardware
495 * When a register map is marked as cache only writes to the register
496 * map API will only update the register cache, they will not cause
497 * any hardware changes. This is useful for allowing portions of
498 * drivers to act as though the device were functioning as normal when
499 * it is disabled for power saving reasons.
501 void regcache_cache_only(struct regmap *map, bool enable)
503 map->lock(map->lock_arg);
504 WARN_ON(map->cache_type != REGCACHE_NONE &&
505 map->cache_bypass && enable);
506 map->cache_only = enable;
507 trace_regmap_cache_only(map, enable);
508 map->unlock(map->lock_arg);
510 EXPORT_SYMBOL_GPL(regcache_cache_only);
513 * regcache_mark_dirty - Indicate that HW registers were reset to default values
517 * Inform regcache that the device has been powered down or reset, so that
518 * on resume, regcache_sync() knows to write out all non-default values
519 * stored in the cache.
521 * If this function is not called, regcache_sync() will assume that
522 * the hardware state still matches the cache state, modulo any writes that
523 * happened when cache_only was true.
525 void regcache_mark_dirty(struct regmap *map)
527 map->lock(map->lock_arg);
528 map->cache_dirty = true;
529 map->no_sync_defaults = true;
530 map->unlock(map->lock_arg);
532 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
535 * regcache_cache_bypass - Put a register map into cache bypass mode
537 * @map: map to configure
538 * @enable: flag if changes should not be written to the cache
540 * When a register map is marked with the cache bypass option, writes
541 * to the register map API will only update the hardware and not
542 * the cache directly. This is useful when syncing the cache back to
545 void regcache_cache_bypass(struct regmap *map, bool enable)
547 map->lock(map->lock_arg);
548 WARN_ON(map->cache_only && enable);
549 map->cache_bypass = enable;
550 trace_regmap_cache_bypass(map, enable);
551 map->unlock(map->lock_arg);
553 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
555 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
558 if (regcache_get_val(map, base, idx) == val)
561 /* Use device native format if possible */
562 if (map->format.format_val) {
563 map->format.format_val(base + (map->cache_word_size * idx),
568 switch (map->cache_word_size) {
601 unsigned int regcache_get_val(struct regmap *map, const void *base,
607 /* Use device native format if possible */
608 if (map->format.parse_val)
609 return map->format.parse_val(regcache_get_val_addr(map, base,
612 switch (map->cache_word_size) {
614 const u8 *cache = base;
619 const u16 *cache = base;
624 const u32 *cache = base;
630 const u64 *cache = base;
642 static int regcache_default_cmp(const void *a, const void *b)
644 const struct reg_default *_a = a;
645 const struct reg_default *_b = b;
647 return _a->reg - _b->reg;
650 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
652 struct reg_default key;
653 struct reg_default *r;
658 r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
659 sizeof(struct reg_default), regcache_default_cmp);
662 return r - map->reg_defaults;
667 static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
672 return test_bit(idx, cache_present);
675 static int regcache_sync_block_single(struct regmap *map, void *block,
676 unsigned long *cache_present,
677 unsigned int block_base,
678 unsigned int start, unsigned int end)
680 unsigned int i, regtmp, val;
683 for (i = start; i < end; i++) {
684 regtmp = block_base + (i * map->reg_stride);
686 if (!regcache_reg_present(cache_present, i) ||
687 !regmap_writeable(map, regtmp))
690 val = regcache_get_val(map, block, i);
691 if (!regcache_reg_needs_sync(map, regtmp, val))
694 map->cache_bypass = true;
696 ret = _regmap_write(map, regtmp, val);
698 map->cache_bypass = false;
700 dev_err(map->dev, "Unable to sync register %#x. %d\n",
704 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
711 static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
712 unsigned int base, unsigned int cur)
714 size_t val_bytes = map->format.val_bytes;
720 count = (cur - base) / map->reg_stride;
722 dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
723 count * val_bytes, count, base, cur - map->reg_stride);
725 map->cache_bypass = true;
727 ret = _regmap_raw_write(map, base, *data, count * val_bytes, false);
729 dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
730 base, cur - map->reg_stride, ret);
732 map->cache_bypass = false;
739 static int regcache_sync_block_raw(struct regmap *map, void *block,
740 unsigned long *cache_present,
741 unsigned int block_base, unsigned int start,
745 unsigned int regtmp = 0;
746 unsigned int base = 0;
747 const void *data = NULL;
750 for (i = start; i < end; i++) {
751 regtmp = block_base + (i * map->reg_stride);
753 if (!regcache_reg_present(cache_present, i) ||
754 !regmap_writeable(map, regtmp)) {
755 ret = regcache_sync_block_raw_flush(map, &data,
762 val = regcache_get_val(map, block, i);
763 if (!regcache_reg_needs_sync(map, regtmp, val)) {
764 ret = regcache_sync_block_raw_flush(map, &data,
772 data = regcache_get_val_addr(map, block, i);
777 return regcache_sync_block_raw_flush(map, &data, base, regtmp +
781 int regcache_sync_block(struct regmap *map, void *block,
782 unsigned long *cache_present,
783 unsigned int block_base, unsigned int start,
786 if (regmap_can_raw_write(map) && !map->use_single_write)
787 return regcache_sync_block_raw(map, block, cache_present,
788 block_base, start, end);
790 return regcache_sync_block_single(map, block, cache_present,
791 block_base, start, end);