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authorOhad Ben-Cohen <ohad@wizery.com>2011-09-05 23:15:06 +0300
committerOhad Ben-Cohen <ohad@wizery.com>2011-09-21 19:45:32 +0300
commitc3c1250e93a7ab1327a9fc49d2a22405672f4204 (patch)
tree2dc99df2ab4657de87a66da7d0a047a95ff27711 /drivers/hwspinlock
parentc97f6dd0fe21dfd658c59c144a1b7fd5d8db04ac (diff)
downloadlinux-c3c1250e93a7ab1327a9fc49d2a22405672f4204.tar.gz
hwspinlock/core/omap: fix id issues on multiple hwspinlock devices
hwspinlock devices provide system-wide hardware locks that are used by remote processors that have no other way to achieve synchronization. To achieve that, each physical lock must have a system-wide id number that is agreed upon, otherwise remote processors can't possibly assume they're using the same hardware lock. Usually boards have a single hwspinlock device, which provides several hwspinlocks, and in this case, they can be trivially numbered 0 to (num-of-locks - 1). In case boards have several hwspinlocks devices, a different base id should be used for each hwspinlock device (they can't all use 0 as a starting id!). While this is certainly not common, it's just plain wrong to just silently use 0 as a base id whenever the hwspinlock driver is probed. This patch provides a hwspinlock_pdata structure, that boards can use to set a different base id for each of the hwspinlock devices they may have, and demonstrates how to use it with the omap hwspinlock driver. While we're at it, make sure the hwspinlock core prints an explicit error message in case an hwspinlock is registered with an id number that already exists; this will help users catch such base id issues. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com> Acked-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'drivers/hwspinlock')
-rw-r--r--drivers/hwspinlock/hwspinlock_core.c2
-rw-r--r--drivers/hwspinlock/omap_hwspinlock.c6
2 files changed, 7 insertions, 1 deletions
diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c
index af5175c5d5f..4eb85b4a320 100644
--- a/drivers/hwspinlock/hwspinlock_core.c
+++ b/drivers/hwspinlock/hwspinlock_core.c
@@ -282,6 +282,8 @@ int hwspin_lock_register(struct hwspinlock *hwlock)
spin_lock(&hwspinlock_tree_lock);
ret = radix_tree_insert(&hwspinlock_tree, hwlock->id, hwlock);
+ if (ret == -EEXIST)
+ pr_err("hwspinlock id %d already exists!\n", hwlock->id);
if (ret)
goto out;
diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c
index d0583480fe3..2044d181e49 100644
--- a/drivers/hwspinlock/omap_hwspinlock.c
+++ b/drivers/hwspinlock/omap_hwspinlock.c
@@ -94,12 +94,16 @@ 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 resource *res;
void __iomem *io_base;
int i, ret;
+ if (!pdata)
+ return -ENODEV;
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
@@ -141,7 +145,7 @@ static int __devinit omap_hwspinlock_probe(struct platform_device *pdev)
omap_lock = &state->lock[i];
omap_lock->lock.dev = &pdev->dev;
- omap_lock->lock.id = i;
+ 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;