msm: kgsl: improve active_cnt and ACTIVE state management
Require any code path which intends to touch the hardware
to take a reference on active_cnt with kgsl_active_count_get()
and release it with kgsl_active_count_put() when finished.
These functions now do the wake / sleep steps that were
previously handled by kgsl_check_suspended() and
kgsl_check_idle().
Additionally, kgsl_pre_hwaccess() will no longer turn on
the clocks, it just enforces via BUG_ON that the clocks
are enabled before a register is touched.
Change-Id: I31b0d067e6d600f0228450dbd73f69caa919ce13
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_pwrctrl.c b/drivers/gpu/msm/kgsl_pwrctrl.c
index 9083054..9d4c245 100644
--- a/drivers/gpu/msm/kgsl_pwrctrl.c
+++ b/drivers/gpu/msm/kgsl_pwrctrl.c
@@ -1012,6 +1012,14 @@
pwr->power_flags = 0;
}
+/**
+ * kgsl_idle_check() - Work function for GPU interrupts and idle timeouts.
+ * @device: The device
+ *
+ * This function is called for work that is queued by the interrupt
+ * handler or the idle timer. It attempts to transition to a clocks
+ * off state if the active_cnt is 0 and the hardware is idle.
+ */
void kgsl_idle_check(struct work_struct *work)
{
struct kgsl_device *device = container_of(work, struct kgsl_device,
@@ -1021,15 +1029,22 @@
return;
mutex_lock(&device->mutex);
- if (device->state & (KGSL_STATE_ACTIVE | KGSL_STATE_NAP)) {
- kgsl_pwrscale_idle(device);
- if (kgsl_pwrctrl_sleep(device) != 0) {
+ kgsl_pwrscale_idle(device);
+
+ if (device->state == KGSL_STATE_ACTIVE
+ || device->state == KGSL_STATE_NAP) {
+ if (device->active_cnt > 0 || kgsl_pwrctrl_sleep(device) != 0) {
+
+ kgsl_pwrctrl_request_state(device, KGSL_STATE_NONE);
+
mod_timer(&device->idle_timer,
jiffies +
device->pwrctrl.interval_timeout);
- /* If the GPU has been too busy to sleep, make sure *
- * that is acurately reflected in the % busy numbers. */
+ /*
+ * If the GPU has been too busy to sleep, make sure
+ * that is acurately reflected in the % busy numbers.
+ */
device->pwrctrl.clk_stats.no_nap_cnt++;
if (device->pwrctrl.clk_stats.no_nap_cnt >
UPDATE_BUSY) {
@@ -1061,54 +1076,26 @@
}
}
+
+/**
+ * kgsl_pre_hwaccess - Enforce preconditions for touching registers
+ * @device: The device
+ *
+ * This function ensures that the correct lock is held and that the GPU
+ * clock is on immediately before a register is read or written. Note
+ * that this function does not check active_cnt because the registers
+ * must be accessed during device start and stop, when the active_cnt
+ * may legitimately be 0.
+ */
void kgsl_pre_hwaccess(struct kgsl_device *device)
{
+ /* In order to touch a register you must hold the device mutex...*/
BUG_ON(!mutex_is_locked(&device->mutex));
- switch (device->state) {
- case KGSL_STATE_ACTIVE:
- return;
- case KGSL_STATE_NAP:
- case KGSL_STATE_SLEEP:
- case KGSL_STATE_SLUMBER:
- kgsl_pwrctrl_wake(device);
- break;
- case KGSL_STATE_SUSPEND:
- kgsl_check_suspended(device);
- break;
- case KGSL_STATE_INIT:
- case KGSL_STATE_HUNG:
- case KGSL_STATE_DUMP_AND_FT:
- if (test_bit(KGSL_PWRFLAGS_CLK_ON,
- &device->pwrctrl.power_flags))
- break;
- else
- KGSL_PWR_ERR(device,
- "hw access while clocks off from state %d\n",
- device->state);
- break;
- default:
- KGSL_PWR_ERR(device, "hw access while in unknown state %d\n",
- device->state);
- break;
- }
+ /* and have the clock on! */
+ BUG_ON(!test_bit(KGSL_PWRFLAGS_CLK_ON, &device->pwrctrl.power_flags));
}
EXPORT_SYMBOL(kgsl_pre_hwaccess);
-void kgsl_check_suspended(struct kgsl_device *device)
-{
- if (device->requested_state == KGSL_STATE_SUSPEND ||
- device->state == KGSL_STATE_SUSPEND) {
- mutex_unlock(&device->mutex);
- wait_for_completion(&device->hwaccess_gate);
- mutex_lock(&device->mutex);
- } else if (device->state == KGSL_STATE_DUMP_AND_FT) {
- mutex_unlock(&device->mutex);
- wait_for_completion(&device->ft_gate);
- mutex_lock(&device->mutex);
- } else if (device->state == KGSL_STATE_SLUMBER)
- kgsl_pwrctrl_wake(device);
-}
-
static int
_nap(struct kgsl_device *device)
{
@@ -1187,6 +1174,8 @@
case KGSL_STATE_NAP:
case KGSL_STATE_SLEEP:
del_timer_sync(&device->idle_timer);
+ /* make sure power is on to stop the device*/
+ kgsl_pwrctrl_enable(device);
device->ftbl->suspend_context(device);
device->ftbl->stop(device);
_sleep_accounting(device);
@@ -1236,9 +1225,9 @@
/******************************************************************/
/* Caller must hold the device mutex. */
-void kgsl_pwrctrl_wake(struct kgsl_device *device)
+int kgsl_pwrctrl_wake(struct kgsl_device *device)
{
- int status;
+ int status = 0;
unsigned int context_id;
unsigned int state = device->state;
unsigned int ts_processed = 0xdeaddead;
@@ -1288,8 +1277,10 @@
KGSL_PWR_WARN(device, "unhandled state %s\n",
kgsl_pwrstate_to_str(device->state));
kgsl_pwrctrl_request_state(device, KGSL_STATE_NONE);
+ status = -EINVAL;
break;
}
+ return status;
}
EXPORT_SYMBOL(kgsl_pwrctrl_wake);
@@ -1355,3 +1346,124 @@
}
EXPORT_SYMBOL(kgsl_pwrstate_to_str);
+
+/**
+ * kgsl_active_count_get() - Increase the device active count
+ * @device: Pointer to a KGSL device
+ *
+ * Increase the active count for the KGSL device and turn on
+ * clocks if this is the first reference. Code paths that need
+ * to touch the hardware or wait for the hardware to complete
+ * an operation must hold an active count reference until they
+ * are finished. An error code will be returned if waking the
+ * device fails. The device mutex must be held while *calling
+ * this function.
+ */
+int kgsl_active_count_get(struct kgsl_device *device)
+{
+ int ret = 0;
+ BUG_ON(!mutex_is_locked(&device->mutex));
+
+ if (device->active_cnt == 0) {
+ if (device->requested_state == KGSL_STATE_SUSPEND ||
+ device->state == KGSL_STATE_SUSPEND) {
+ mutex_unlock(&device->mutex);
+ wait_for_completion(&device->hwaccess_gate);
+ mutex_lock(&device->mutex);
+ } else if (device->state == KGSL_STATE_DUMP_AND_FT) {
+ mutex_unlock(&device->mutex);
+ wait_for_completion(&device->ft_gate);
+ mutex_lock(&device->mutex);
+ }
+ ret = kgsl_pwrctrl_wake(device);
+ }
+ if (ret == 0)
+ device->active_cnt++;
+ return ret;
+}
+EXPORT_SYMBOL(kgsl_active_count_get);
+
+/**
+ * kgsl_active_count_get_light() - Increase the device active count
+ * @device: Pointer to a KGSL device
+ *
+ * Increase the active count for the KGSL device WITHOUT
+ * turning on the clocks. Currently this is only used for creating
+ * kgsl_events. The device mutex must be held while calling this function.
+ */
+int kgsl_active_count_get_light(struct kgsl_device *device)
+{
+ BUG_ON(!mutex_is_locked(&device->mutex));
+
+ if (device->state != KGSL_STATE_ACTIVE) {
+ dev_WARN_ONCE(device->dev, 1, "device in unexpected state %s\n",
+ kgsl_pwrstate_to_str(device->state));
+ return -EINVAL;
+ }
+
+ if (device->active_cnt == 0) {
+ dev_WARN_ONCE(device->dev, 1, "active count is 0!\n");
+ return -EINVAL;
+ }
+
+ device->active_cnt++;
+ return 0;
+}
+EXPORT_SYMBOL(kgsl_active_count_get_light);
+
+/**
+ * kgsl_active_count_put() - Decrease the device active count
+ * @device: Pointer to a KGSL device
+ *
+ * Decrease the active count for the KGSL device and turn off
+ * clocks if there are no remaining references. This function will
+ * transition the device to NAP if there are no other pending state
+ * changes. It also completes the suspend gate. The device mutex must
+ * be held while calling this function.
+ */
+void kgsl_active_count_put(struct kgsl_device *device)
+{
+ BUG_ON(!mutex_is_locked(&device->mutex));
+ BUG_ON(device->active_cnt == 0);
+
+ kgsl_pwrscale_idle(device);
+ if (device->active_cnt > 1) {
+ device->active_cnt--;
+ return;
+ }
+
+ INIT_COMPLETION(device->suspend_gate);
+
+ if (device->pwrctrl.nap_allowed == true &&
+ (device->state == KGSL_STATE_ACTIVE &&
+ device->requested_state == KGSL_STATE_NONE)) {
+ kgsl_pwrctrl_request_state(device, KGSL_STATE_NAP);
+ if (kgsl_pwrctrl_sleep(device) != 0)
+ mod_timer(&device->idle_timer,
+ jiffies
+ + device->pwrctrl.interval_timeout);
+ }
+ device->active_cnt--;
+
+ if (device->active_cnt == 0)
+ complete(&device->suspend_gate);
+}
+EXPORT_SYMBOL(kgsl_active_count_put);
+
+/**
+ * kgsl_active_count_wait() - Wait for activity to finish.
+ * @device: Pointer to a KGSL device
+ *
+ * Block until all active_cnt users put() their reference.
+ */
+void kgsl_active_count_wait(struct kgsl_device *device)
+{
+ BUG_ON(!mutex_is_locked(&device->mutex));
+
+ if (device->active_cnt != 0) {
+ mutex_unlock(&device->mutex);
+ wait_for_completion(&device->suspend_gate);
+ mutex_lock(&device->mutex);
+ }
+}
+EXPORT_SYMBOL(kgsl_active_count_wait);