2 * Register cache access API
4 * Copyright 2011 Wolfson Microelectronics plc
6 * Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/bsearch.h>
14 #include <linux/device.h>
15 #include <linux/export.h>
16 #include <linux/slab.h>
17 #include <linux/sort.h>
22 static const struct regcache_ops *cache_types[] = {
28 static int regcache_hw_init(struct regmap *map)
36 if (!map->num_reg_defaults_raw)
39 /* calculate the size of reg_defaults */
40 for (count = 0, i = 0; i < map->num_reg_defaults_raw; i++)
41 if (!regmap_volatile(map, i * map->reg_stride))
44 /* all registers are volatile, so just bypass */
46 map->cache_bypass = true;
50 map->num_reg_defaults = count;
51 map->reg_defaults = kmalloc_array(count, sizeof(struct reg_default),
53 if (!map->reg_defaults)
56 if (!map->reg_defaults_raw) {
57 bool cache_bypass = map->cache_bypass;
58 dev_warn(map->dev, "No cache defaults, reading back from HW\n");
60 /* Bypass the cache access till data read from HW*/
61 map->cache_bypass = true;
62 tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
67 ret = regmap_raw_read(map, 0, tmp_buf,
68 map->num_reg_defaults_raw);
69 map->cache_bypass = cache_bypass;
73 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 if (regmap_volatile(map, i * map->reg_stride))
81 val = regcache_get_val(map, map->reg_defaults_raw, i);
82 map->reg_defaults[j].reg = i * map->reg_stride;
83 map->reg_defaults[j].def = val;
92 kfree(map->reg_defaults);
97 int regcache_init(struct regmap *map, const struct regmap_config *config)
103 for (i = 0; i < config->num_reg_defaults; i++)
104 if (config->reg_defaults[i].reg % map->reg_stride)
107 if (map->cache_type == REGCACHE_NONE) {
108 map->cache_bypass = true;
112 for (i = 0; i < ARRAY_SIZE(cache_types); i++)
113 if (cache_types[i]->type == map->cache_type)
116 if (i == ARRAY_SIZE(cache_types)) {
117 dev_err(map->dev, "Could not match compress type: %d\n",
122 map->num_reg_defaults = config->num_reg_defaults;
123 map->num_reg_defaults_raw = config->num_reg_defaults_raw;
124 map->reg_defaults_raw = config->reg_defaults_raw;
125 map->cache_word_size = DIV_ROUND_UP(config->val_bits, 8);
126 map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
129 map->cache_ops = cache_types[i];
131 if (!map->cache_ops->read ||
132 !map->cache_ops->write ||
133 !map->cache_ops->name)
136 /* We still need to ensure that the reg_defaults
137 * won't vanish from under us. We'll need to make
140 if (config->reg_defaults) {
141 if (!map->num_reg_defaults)
143 tmp_buf = kmemdup(config->reg_defaults, map->num_reg_defaults *
144 sizeof(struct reg_default), GFP_KERNEL);
147 map->reg_defaults = tmp_buf;
148 } else if (map->num_reg_defaults_raw) {
149 /* Some devices such as PMICs don't have cache defaults,
150 * we cope with this by reading back the HW registers and
151 * crafting the cache defaults by hand.
153 ret = regcache_hw_init(map);
156 if (map->cache_bypass)
160 if (!map->max_register)
161 map->max_register = map->num_reg_defaults_raw;
163 if (map->cache_ops->init) {
164 dev_dbg(map->dev, "Initializing %s cache\n",
165 map->cache_ops->name);
166 ret = map->cache_ops->init(map);
173 kfree(map->reg_defaults);
175 kfree(map->reg_defaults_raw);
180 void regcache_exit(struct regmap *map)
182 if (map->cache_type == REGCACHE_NONE)
185 BUG_ON(!map->cache_ops);
187 kfree(map->reg_defaults);
189 kfree(map->reg_defaults_raw);
191 if (map->cache_ops->exit) {
192 dev_dbg(map->dev, "Destroying %s cache\n",
193 map->cache_ops->name);
194 map->cache_ops->exit(map);
199 * regcache_read: Fetch the value of a given register from the cache.
201 * @map: map to configure.
202 * @reg: The register index.
203 * @value: The value to be returned.
205 * Return a negative value on failure, 0 on success.
207 int regcache_read(struct regmap *map,
208 unsigned int reg, unsigned int *value)
212 if (map->cache_type == REGCACHE_NONE)
215 BUG_ON(!map->cache_ops);
217 if (!regmap_volatile(map, reg)) {
218 ret = map->cache_ops->read(map, reg, value);
221 trace_regmap_reg_read_cache(map, reg, *value);
230 * regcache_write: Set the value of a given register in the cache.
232 * @map: map to configure.
233 * @reg: The register index.
234 * @value: The new register value.
236 * Return a negative value on failure, 0 on success.
238 int regcache_write(struct regmap *map,
239 unsigned int reg, unsigned int value)
241 if (map->cache_type == REGCACHE_NONE)
244 BUG_ON(!map->cache_ops);
246 if (!regmap_volatile(map, reg))
247 return map->cache_ops->write(map, reg, value);
252 static bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
257 /* If we don't know the chip just got reset, then sync everything. */
258 if (!map->no_sync_defaults)
261 /* Is this the hardware default? If so skip. */
262 ret = regcache_lookup_reg(map, reg);
263 if (ret >= 0 && val == map->reg_defaults[ret].def)
268 static int regcache_default_sync(struct regmap *map, unsigned int min,
273 for (reg = min; reg <= max; reg += map->reg_stride) {
277 if (regmap_volatile(map, reg) ||
278 !regmap_writeable(map, reg))
281 ret = regcache_read(map, reg, &val);
285 if (!regcache_reg_needs_sync(map, reg, val))
288 map->cache_bypass = true;
289 ret = _regmap_write(map, reg, val);
290 map->cache_bypass = false;
292 dev_err(map->dev, "Unable to sync register %#x. %d\n",
296 dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
303 * regcache_sync: Sync the register cache with the hardware.
305 * @map: map to configure.
307 * Any registers that should not be synced should be marked as
308 * volatile. In general drivers can choose not to use the provided
309 * syncing functionality if they so require.
311 * Return a negative value on failure, 0 on success.
313 int regcache_sync(struct regmap *map)
320 BUG_ON(!map->cache_ops);
322 map->lock(map->lock_arg);
323 /* Remember the initial bypass state */
324 bypass = map->cache_bypass;
325 dev_dbg(map->dev, "Syncing %s cache\n",
326 map->cache_ops->name);
327 name = map->cache_ops->name;
328 trace_regcache_sync(map, name, "start");
330 if (!map->cache_dirty)
335 /* Apply any patch first */
336 map->cache_bypass = true;
337 for (i = 0; i < map->patch_regs; i++) {
338 ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
340 dev_err(map->dev, "Failed to write %x = %x: %d\n",
341 map->patch[i].reg, map->patch[i].def, ret);
345 map->cache_bypass = false;
347 if (map->cache_ops->sync)
348 ret = map->cache_ops->sync(map, 0, map->max_register);
350 ret = regcache_default_sync(map, 0, map->max_register);
353 map->cache_dirty = false;
356 /* Restore the bypass state */
358 map->cache_bypass = bypass;
359 map->no_sync_defaults = false;
360 map->unlock(map->lock_arg);
362 regmap_async_complete(map);
364 trace_regcache_sync(map, name, "stop");
368 EXPORT_SYMBOL_GPL(regcache_sync);
371 * regcache_sync_region: Sync part of the register cache with the hardware.
374 * @min: first register to sync
375 * @max: last register to sync
377 * Write all non-default register values in the specified region to
380 * Return a negative value on failure, 0 on success.
382 int regcache_sync_region(struct regmap *map, unsigned int min,
389 BUG_ON(!map->cache_ops);
391 map->lock(map->lock_arg);
393 /* Remember the initial bypass state */
394 bypass = map->cache_bypass;
396 name = map->cache_ops->name;
397 dev_dbg(map->dev, "Syncing %s cache from %d-%d\n", name, min, max);
399 trace_regcache_sync(map, name, "start region");
401 if (!map->cache_dirty)
406 if (map->cache_ops->sync)
407 ret = map->cache_ops->sync(map, min, max);
409 ret = regcache_default_sync(map, min, max);
412 /* Restore the bypass state */
413 map->cache_bypass = bypass;
415 map->no_sync_defaults = false;
416 map->unlock(map->lock_arg);
418 regmap_async_complete(map);
420 trace_regcache_sync(map, name, "stop region");
424 EXPORT_SYMBOL_GPL(regcache_sync_region);
427 * regcache_drop_region: Discard part of the register cache
429 * @map: map to operate on
430 * @min: first register to discard
431 * @max: last register to discard
433 * Discard part of the register cache.
435 * Return a negative value on failure, 0 on success.
437 int regcache_drop_region(struct regmap *map, unsigned int min,
442 if (!map->cache_ops || !map->cache_ops->drop)
445 map->lock(map->lock_arg);
447 trace_regcache_drop_region(map, min, max);
449 ret = map->cache_ops->drop(map, min, max);
451 map->unlock(map->lock_arg);
455 EXPORT_SYMBOL_GPL(regcache_drop_region);
458 * regcache_cache_only: Put a register map into cache only mode
460 * @map: map to configure
461 * @cache_only: flag if changes should be written to the hardware
463 * When a register map is marked as cache only writes to the register
464 * map API will only update the register cache, they will not cause
465 * any hardware changes. This is useful for allowing portions of
466 * drivers to act as though the device were functioning as normal when
467 * it is disabled for power saving reasons.
469 void regcache_cache_only(struct regmap *map, bool enable)
471 map->lock(map->lock_arg);
472 WARN_ON(map->cache_bypass && enable);
473 map->cache_only = enable;
474 trace_regmap_cache_only(map, enable);
475 map->unlock(map->lock_arg);
477 EXPORT_SYMBOL_GPL(regcache_cache_only);
480 * regcache_mark_dirty: Indicate that HW registers were reset to default values
484 * Inform regcache that the device has been powered down or reset, so that
485 * on resume, regcache_sync() knows to write out all non-default values
486 * stored in the cache.
488 * If this function is not called, regcache_sync() will assume that
489 * the hardware state still matches the cache state, modulo any writes that
490 * happened when cache_only was true.
492 void regcache_mark_dirty(struct regmap *map)
494 map->lock(map->lock_arg);
495 map->cache_dirty = true;
496 map->no_sync_defaults = true;
497 map->unlock(map->lock_arg);
499 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
502 * regcache_cache_bypass: Put a register map into cache bypass mode
504 * @map: map to configure
505 * @cache_bypass: flag if changes should not be written to the hardware
507 * When a register map is marked with the cache bypass option, writes
508 * to the register map API will only update the hardware and not the
509 * the cache directly. This is useful when syncing the cache back to
512 void regcache_cache_bypass(struct regmap *map, bool enable)
514 map->lock(map->lock_arg);
515 WARN_ON(map->cache_only && enable);
516 map->cache_bypass = enable;
517 trace_regmap_cache_bypass(map, enable);
518 map->unlock(map->lock_arg);
520 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
522 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
525 if (regcache_get_val(map, base, idx) == val)
528 /* Use device native format if possible */
529 if (map->format.format_val) {
530 map->format.format_val(base + (map->cache_word_size * idx),
535 switch (map->cache_word_size) {
557 unsigned int regcache_get_val(struct regmap *map, const void *base,
563 /* Use device native format if possible */
564 if (map->format.parse_val)
565 return map->format.parse_val(regcache_get_val_addr(map, base,
568 switch (map->cache_word_size) {
570 const u8 *cache = base;
574 const u16 *cache = base;
578 const u32 *cache = base;
588 static int regcache_default_cmp(const void *a, const void *b)
590 const struct reg_default *_a = a;
591 const struct reg_default *_b = b;
593 return _a->reg - _b->reg;
596 int regcache_lookup_reg(struct regmap *map, unsigned int reg)
598 struct reg_default key;
599 struct reg_default *r;
604 r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
605 sizeof(struct reg_default), regcache_default_cmp);
608 return r - map->reg_defaults;
613 static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
618 return test_bit(idx, cache_present);
621 static int regcache_sync_block_single(struct regmap *map, void *block,
622 unsigned long *cache_present,
623 unsigned int block_base,
624 unsigned int start, unsigned int end)
626 unsigned int i, regtmp, val;
629 for (i = start; i < end; i++) {
630 regtmp = block_base + (i * map->reg_stride);
632 if (!regcache_reg_present(cache_present, i) ||
633 !regmap_writeable(map, regtmp))
636 val = regcache_get_val(map, block, i);
637 if (!regcache_reg_needs_sync(map, regtmp, val))
640 map->cache_bypass = true;
642 ret = _regmap_write(map, regtmp, val);
644 map->cache_bypass = false;
646 dev_err(map->dev, "Unable to sync register %#x. %d\n",
650 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
657 static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
658 unsigned int base, unsigned int cur)
660 size_t val_bytes = map->format.val_bytes;
666 count = (cur - base) / map->reg_stride;
668 dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
669 count * val_bytes, count, base, cur - map->reg_stride);
671 map->cache_bypass = true;
673 ret = _regmap_raw_write(map, base, *data, count * val_bytes);
675 dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
676 base, cur - map->reg_stride, ret);
678 map->cache_bypass = false;
685 static int regcache_sync_block_raw(struct regmap *map, void *block,
686 unsigned long *cache_present,
687 unsigned int block_base, unsigned int start,
691 unsigned int regtmp = 0;
692 unsigned int base = 0;
693 const void *data = NULL;
696 for (i = start; i < end; i++) {
697 regtmp = block_base + (i * map->reg_stride);
699 if (!regcache_reg_present(cache_present, i) ||
700 !regmap_writeable(map, regtmp)) {
701 ret = regcache_sync_block_raw_flush(map, &data,
708 val = regcache_get_val(map, block, i);
709 if (!regcache_reg_needs_sync(map, regtmp, val)) {
710 ret = regcache_sync_block_raw_flush(map, &data,
718 data = regcache_get_val_addr(map, block, i);
723 return regcache_sync_block_raw_flush(map, &data, base, regtmp +
727 int regcache_sync_block(struct regmap *map, void *block,
728 unsigned long *cache_present,
729 unsigned int block_base, unsigned int start,
732 if (regmap_can_raw_write(map) && !map->use_single_write)
733 return regcache_sync_block_raw(map, block, cache_present,
734 block_base, start, end);
736 return regcache_sync_block_single(map, block, cache_present,
737 block_base, start, end);