regmap: Add hardware spinlock support

On some platforms, when reading or writing some special registers through
regmap, we should acquire one hardware spinlock to synchronize between
the multiple subsystems. Thus this patch adds the hardware spinlock
support for regmap.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

3 files changed, 93 insertions, 16 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 2a4435d76028..8641183cac2f 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -157,6 +157,8 @@ struct regmap {
 
         struct rb_root range_tree;
         void *selector_work_buf;        /* Scratch buffer used for selector */
+
+        struct hwspinlock *hwlock;
 };
 
 struct regcache_ops {
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index b9a779a4a739..999e981a174a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -20,6 +20,7 @@
 #include <linux/sched.h>
 #include <linux/delay.h>
 #include <linux/log2.h>
+#include <linux/hwspinlock.h>
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
@@ -413,6 +414,49 @@ static unsigned int regmap_parse_64_native(const void *buf)
 }
 #endif
 
+static void regmap_lock_hwlock(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_lock_timeout(map->hwlock, UINT_MAX);
+}
+
+static void regmap_lock_hwlock_irq(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_lock_timeout_irq(map->hwlock, UINT_MAX);
+}
+
+static void regmap_lock_hwlock_irqsave(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_lock_timeout_irqsave(map->hwlock, UINT_MAX,
+                                    &map->spinlock_flags);
+}
+
+static void regmap_unlock_hwlock(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_unlock(map->hwlock);
+}
+
+static void regmap_unlock_hwlock_irq(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_unlock_irq(map->hwlock);
+}
+
+static void regmap_unlock_hwlock_irqrestore(void *__map)
+{
+        struct regmap *map = __map;
+
+        hwspin_unlock_irqrestore(map->hwlock, &map->spinlock_flags);
+}
+
 static void regmap_lock_mutex(void *__map)
 {
         struct regmap *map = __map;
@@ -627,6 +671,29 @@ struct regmap *__regmap_init(struct device *dev,
                 map->lock = config->lock;
                 map->unlock = config->unlock;
                 map->lock_arg = config->lock_arg;
+        } else if (config->hwlock_id) {
+                map->hwlock = hwspin_lock_request_specific(config->hwlock_id);
+                if (!map->hwlock) {
+                        ret = -ENXIO;
+                        goto err_map;
+                }
+
+                switch (config->hwlock_mode) {
+                case HWLOCK_IRQSTATE:
+                        map->lock = regmap_lock_hwlock_irqsave;
+                        map->unlock = regmap_unlock_hwlock_irqrestore;
+                        break;
+                case HWLOCK_IRQ:
+                        map->lock = regmap_lock_hwlock_irq;
+                        map->unlock = regmap_unlock_hwlock_irq;
+                        break;
+                default:
+                        map->lock = regmap_lock_hwlock;
+                        map->unlock = regmap_unlock_hwlock;
+                        break;
+                }
+
+                map->lock_arg = map;
         } else {
                 if ((bus && bus->fast_io) ||
                     config->fast_io) {
@@ -729,7 +796,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_write = regmap_format_2_6_write;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
@@ -739,7 +806,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_write = regmap_format_4_12_write;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
@@ -749,7 +816,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_write = regmap_format_7_9_write;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
@@ -759,7 +826,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_write = regmap_format_10_14_write;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
@@ -779,13 +846,13 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_reg = regmap_format_16_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
         case 24:
                 if (reg_endian != REGMAP_ENDIAN_BIG)
-                        goto err_map;
+                        goto err_hwlock;
                 map->format.format_reg = regmap_format_24;
                 break;
 
@@ -801,7 +868,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_reg = regmap_format_32_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 
@@ -818,13 +885,13 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.format_reg = regmap_format_64_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 #endif
 
         default:
-                goto err_map;
+                goto err_hwlock;
         }
 
         if (val_endian == REGMAP_ENDIAN_NATIVE)
@@ -853,12 +920,12 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.parse_val = regmap_parse_16_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
         case 24:
                 if (val_endian != REGMAP_ENDIAN_BIG)
-                        goto err_map;
+                        goto err_hwlock;
                 map->format.format_val = regmap_format_24;
                 map->format.parse_val = regmap_parse_24;
                 break;
@@ -879,7 +946,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.parse_val = regmap_parse_32_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 #ifdef CONFIG_64BIT
@@ -900,7 +967,7 @@ struct regmap *__regmap_init(struct device *dev,
                         map->format.parse_val = regmap_parse_64_native;
                         break;
                 default:
-                        goto err_map;
+                        goto err_hwlock;
                 }
                 break;
 #endif
@@ -909,18 +976,18 @@ struct regmap *__regmap_init(struct device *dev,
         if (map->format.format_write) {
                 if ((reg_endian != REGMAP_ENDIAN_BIG) ||
                     (val_endian != REGMAP_ENDIAN_BIG))
-                        goto err_map;
+                        goto err_hwlock;
                 map->use_single_write = true;
         }
 
         if (!map->format.format_write &&
             !(map->format.format_reg && map->format.format_val))
-                goto err_map;
+                goto err_hwlock;
 
         map->work_buf = kzalloc(map->format.buf_size, GFP_KERNEL);
         if (map->work_buf == NULL) {
                 ret = -ENOMEM;
-                goto err_map;
+                goto err_hwlock;
         }
 
         if (map->format.format_write) {
@@ -1041,6 +1108,8 @@ err_regcache:
 err_range:
         regmap_range_exit(map);
         kfree(map->work_buf);
+err_hwlock:
+        hwspin_lock_free(map->hwlock);
 err_map:
         kfree(map);
 err:
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 978abfbac617..edc32aac84d7 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -273,6 +273,9 @@ typedef void (*regmap_unlock)(void *);
  *
  * @ranges: Array of configuration entries for virtual address ranges.
  * @num_ranges: Number of range configuration entries.
+ * @hwlock_id: Specify the hardware spinlock id.
+ * @hwlock_mode: The hardware spinlock mode, should be HWLOCK_IRQSTATE,
+ *               HWLOCK_IRQ or 0.
  */
 struct regmap_config {
         const char *name;
@@ -317,6 +320,9 @@ struct regmap_config {
 
         const struct regmap_range_cfg *ranges;
         unsigned int num_ranges;
+
+        unsigned int hwlock_id;
+        unsigned int hwlock_mode;
 };
 
 /**