[PATCH 1/2] regmap: Add hardware spinlock support

[Baolin Wang]

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@xxxxxxxxxx>
---
 drivers/base/regmap/internal.h |    3 +
 drivers/base/regmap/regmap.c   |  118 ++++++++++++++++++++++++++++++++++------
 include/linux/regmap.h         |    9 +++
 3 files changed, 114 insertions(+), 16 deletions(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 2a4435d..bb8b663 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -157,6 +157,9 @@ struct regmap {
 
 	struct rb_root range_tree;
 	void *selector_work_buf;	/* Scratch buffer used for selector */
+
+	struct hwspinlock *hwlock;
+	unsigned int hwlock_timeout;
 };
 
 struct regcache_ops {
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index b9a779a..615e8d0 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -413,6 +413,71 @@ static unsigned int regmap_parse_64_native(const void *buf)
 }
 #endif
 
+static void regmap_lock_hwlock(void *__map)
+{
+	struct regmap *map = __map;
+	int ret;
+
+	if (map->hwlock_timeout)
+		ret = hwspin_lock_timeout(map->hwlock, map->hwlock_timeout);
+	else
+		ret = hwspin_trylock(map->hwlock);
+
+	if (ret)
+		dev_err(map->dev, "Failed to get hwlock %d\n", ret);
+}
+
+static void regmap_lock_hwlock_irq(void *__map)
+{
+	struct regmap *map = __map;
+	int ret;
+
+	if (map->hwlock_timeout)
+		ret = hwspin_lock_timeout_irq(map->hwlock, map->hwlock_timeout);
+	else
+		ret = hwspin_trylock_irq(map->hwlock);
+
+	if (ret)
+		dev_err(map->dev, "Failed to get hwlock %d\n", ret);
+}
+
+static void regmap_lock_hwlock_irqsave(void *__map)
+{
+	struct regmap *map = __map;
+	int ret;
+
+	if (map->hwlock_timeout)
+		ret = hwspin_lock_timeout_irqsave(map->hwlock,
+						  map->hwlock_timeout,
+						  &map->spinlock_flags);
+	else
+		ret = hwspin_trylock_irqsave(map->hwlock, &map->spinlock_flags);
+
+	if (ret)
+		dev_err(map->dev, "Failed to get hwlock %d\n", ret);
+}
+
+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 +692,25 @@ 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;
+		}
+
+		map->hwlock_timeout = config->hwlock_timeout;
+		if (config->hwlock_mode == HWLOCK_IRQSTATE) {
+			map->lock = regmap_lock_hwlock_irqsave;
+			map->unlock = regmap_unlock_hwlock_irqrestore;
+		} else if (config->hwlock_mode == HWLOCK_IRQ) {
+			map->lock = regmap_lock_hwlock_irq;
+			map->unlock = regmap_unlock_hwlock_irq;
+		} else {
+			map->lock = regmap_lock_hwlock;
+			map->unlock = regmap_unlock_hwlock;
+		}
+		map->lock_arg = map;
 	} else {
 		if ((bus && bus->fast_io) ||
 		    config->fast_io) {
@@ -729,7 +813,7 @@ 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 +823,7 @@ 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 +833,7 @@ 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 +843,7 @@ 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 +863,13 @@ 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 +885,7 @@ 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 +902,13 @@ 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 +937,12 @@ 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 +963,7 @@ 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 +984,7 @@ 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 +993,18 @@ 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 +1125,8 @@ struct regmap *__regmap_init(struct device *dev,
 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 978abfb..fe958e2 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -19,6 +19,7 @@
 #include <linux/err.h>
 #include <linux/bug.h>
 #include <linux/lockdep.h>
+#include <linux/hwspinlock.h>
 
 struct module;
 struct device;
@@ -273,6 +274,10 @@ struct regmap_access_table {
  *
  * @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.
+ * @hwlock_timeout: Timeout value in msecs.
  */
 struct regmap_config {
 	const char *name;
@@ -317,6 +322,10 @@ struct regmap_config {
 
 	const struct regmap_range_cfg *ranges;
 	unsigned int num_ranges;
+
+	unsigned int hwlock_id;
+	unsigned int hwlock_mode;
+	unsigned int hwlock_timeout;
 };
 
 /**
-- 
1.7.9.5