OMAP: DSS2: DSI: change DSI bus_lock to semaphore
Physical DSI bus is protected by a mutex. This patch changed the mutex to
a semaphore, so that we can lock and unlock the bus_lock from different
threads.
This is needed as the update process is started by user space program, and
thus the lock is acquired in that context, but the lock can be released in
different context, a work thread via irq.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index 928b5e4..53fc0f8 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -27,6 +27,7 @@
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/semaphore.h>
#include <linux/seq_file.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
@@ -227,7 +228,7 @@
} vc[4];
struct mutex lock;
- struct mutex bus_lock;
+ struct semaphore bus_lock;
unsigned pll_locked;
@@ -298,19 +299,19 @@
void dsi_bus_lock(void)
{
- mutex_lock(&dsi.bus_lock);
+ down(&dsi.bus_lock);
}
EXPORT_SYMBOL(dsi_bus_lock);
void dsi_bus_unlock(void)
{
- mutex_unlock(&dsi.bus_lock);
+ up(&dsi.bus_lock);
}
EXPORT_SYMBOL(dsi_bus_unlock);
static bool dsi_bus_is_locked(void)
{
- return mutex_is_locked(&dsi.bus_lock);
+ return dsi.bus_lock.count == 0;
}
static inline int wait_for_bit_change(const struct dsi_reg idx, int bitnum,
@@ -3002,8 +3003,6 @@
u16 x, y, w, h;
while (1) {
- bool sched;
-
wait_event_interruptible(dsi.waitqueue,
dsi.update_mode == OMAP_DSS_UPDATE_AUTO ||
(dsi.update_mode == OMAP_DSS_UPDATE_MANUAL &&
@@ -3089,16 +3088,9 @@
dsi_perf_show("L4");
}
- sched = atomic_read(&dsi.bus_lock.count) < 0;
-
complete_all(&dsi.update_completion);
dsi_bus_unlock();
-
- /* XXX We need to give others chance to get the bus lock. Is
- * there a better way for this? */
- if (dsi.update_mode == OMAP_DSS_UPDATE_AUTO && sched)
- schedule_timeout_interruptible(1);
}
DSSDBG("update thread exiting\n");
@@ -3798,7 +3790,7 @@
spin_lock_init(&dsi.update_lock);
mutex_init(&dsi.lock);
- mutex_init(&dsi.bus_lock);
+ sema_init(&dsi.bus_lock, 1);
#ifdef DSI_CATCH_MISSING_TE
init_timer(&dsi.te_timer);