hwspinlock/core: register a bank of hwspinlocks in a single API call

Hardware Spinlock devices usually contain numerous locks (known
devices today support between 32 to 256 locks).

Originally hwspinlock core required drivers to register (and later,
when needed, unregister) each lock separately.

That worked, but required hwspinlocks drivers to do a bit extra work
when they were probed/removed.

This patch changes hwspin_lock_{un}register() to allow a bank of
hwspinlocks to be {un}registered in a single invocation.

A new 'struct hwspinlock_device', which contains an array of 'struct
hwspinlock's is now being passed to the core upon registration (so
instead of wrapping each struct hwspinlock, a priv member has been added
to allow drivers to piggyback their private data with each hwspinlock).

While at it, several per-lock members were moved to be per-device:
1. struct device *dev
2. struct hwspinlock_ops *ops

In addition, now that the array of locks is handled by the core,
there's no reason to maintain a per-lock 'int id' member: the id of the
lock anyway equals to its index in the bank's array plus the bank's
base_id.
Remove this per-lock id member too, and instead use a simple pointers
arithmetic to derive it.

As a result of this change, hwspinlocks drivers are now simpler and smaller
(about %20 code reduction) and the memory footprint of the hwspinlock
framework is reduced.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 29 insertions, 57 deletions

diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c
index 2044d181e49d..aec30064a466 100644
--- a/drivers/hwspinlock/omap_hwspinlock.c
+++ b/drivers/hwspinlock/omap_hwspinlock.c
@@ -41,34 +41,20 @@
 #define SPINLOCK_NOTTAKEN		(0)	/* free */
 #define SPINLOCK_TAKEN			(1)	/* locked */
 
-#define to_omap_hwspinlock(lock)	\
-	container_of(lock, struct omap_hwspinlock, lock)
-
-struct omap_hwspinlock {
-	struct hwspinlock lock;
-	void __iomem *addr;
-};
-
-struct omap_hwspinlock_state {
-	int num_locks;			/* Total number of locks in system */
-	void __iomem *io_base;		/* Mapped base address */
-	struct omap_hwspinlock lock[0];	/* Array of 'num_locks' locks */
-};
-
 static int omap_hwspinlock_trylock(struct hwspinlock *lock)
 {
-	struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
+	void __iomem *lock_addr = lock->priv;
 
 	/* attempt to acquire the lock by reading its value */
-	return (SPINLOCK_NOTTAKEN == readl(omap_lock->addr));
+	return (SPINLOCK_NOTTAKEN == readl(lock_addr));
 }
 
 static void omap_hwspinlock_unlock(struct hwspinlock *lock)
 {
-	struct omap_hwspinlock *omap_lock = to_omap_hwspinlock(lock);
+	void __iomem *lock_addr = lock->priv;
 
 	/* release the lock by writing 0 to it */
-	writel(SPINLOCK_NOTTAKEN, omap_lock->addr);
+	writel(SPINLOCK_NOTTAKEN, lock_addr);
 }
 
 /*
@@ -95,11 +81,11 @@ static const struct hwspinlock_ops omap_hwspinlock_ops = {
 static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
 {
 	struct hwspinlock_pdata *pdata = pdev->dev.platform_data;
-	struct omap_hwspinlock *omap_lock;
-	struct omap_hwspinlock_state *state;
+	struct hwspinlock_device *bank;
+	struct hwspinlock *hwlock;
 	struct resource *res;
 	void __iomem *io_base;
-	int i, ret;
+	int num_locks, i, ret;
 
 	if (!pdata)
 		return -ENODEV;
@@ -122,18 +108,18 @@ static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
 		goto iounmap_base;
 	}
 
-	i *= 32; /* actual number of locks in this device */
+	num_locks = i * 32; /* actual number of locks in this device */
 
-	state = kzalloc(sizeof(*state) + i * sizeof(*omap_lock), GFP_KERNEL);
-	if (!state) {
+	bank = kzalloc(sizeof(*bank) + num_locks * sizeof(*hwlock), GFP_KERNEL);
+	if (!bank) {
 		ret = -ENOMEM;
 		goto iounmap_base;
 	}
 
-	state->num_locks = i;
-	state->io_base = io_base;
+	platform_set_drvdata(pdev, bank);
 
-	platform_set_drvdata(pdev, state);
+	for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++)
+		hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
 
 	/*
 	 * runtime PM will make sure the clock of this module is
@@ -141,26 +127,16 @@ static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
 	 */
 	pm_runtime_enable(&pdev->dev);
 
-	for (i = 0; i < state->num_locks; i++) {
-		omap_lock = &state->lock[i];
-
-		omap_lock->lock.dev = &pdev->dev;
-		omap_lock->lock.id = pdata->base_id + i;
-		omap_lock->lock.ops = &omap_hwspinlock_ops;
-		omap_lock->addr = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i;
-
-		ret = hwspin_lock_register(&omap_lock->lock);
-		if (ret)
-			goto free_locks;
-	}
+	ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops,
+						pdata->base_id, num_locks);
+	if (ret)
+		goto reg_fail;
 
 	return 0;
 
-free_locks:
-	while (--i >= 0)
-		hwspin_lock_unregister(i);
+reg_fail:
 	pm_runtime_disable(&pdev->dev);
-	kfree(state);
+	kfree(bank);
 iounmap_base:
 	iounmap(io_base);
 	return ret;
@@ -168,23 +144,19 @@ iounmap_base:
 
 static int omap_hwspinlock_remove(struct platform_device *pdev)
 {
-	struct omap_hwspinlock_state *state = platform_get_drvdata(pdev);
-	struct hwspinlock *lock;
-	int i;
-
-	for (i = 0; i < state->num_locks; i++) {
-		lock = hwspin_lock_unregister(i);
-		/* this shouldn't happen at this point. if it does, at least
-		 * don't continue with the remove */
-		if (!lock) {
-			dev_err(&pdev->dev, "%s: failed on %d\n", __func__, i);
-			return -EBUSY;
-		}
+	struct hwspinlock_device *bank = platform_get_drvdata(pdev);
+	void __iomem *io_base = bank->lock[0].priv - LOCK_BASE_OFFSET;
+	int ret;
+
+	ret = hwspin_lock_unregister(bank);
+	if (ret) {
+		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
+		return ret;
 	}
 
 	pm_runtime_disable(&pdev->dev);
-	iounmap(state->io_base);
-	kfree(state);
+	iounmap(io_base);
+	kfree(bank);
 
 	return 0;
 }