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Subject[PATCH v10 4/4] CMDQ: save more energy in idle
Date
Use clk_disable_unprepare instead of clk_disable to save more energy
when CMDQ is idle.

Signed-off-by: HS Liao <hs.liao@mediatek.com>
---
drivers/soc/mediatek/mtk-cmdq.c | 55 +++++++++++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 8 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-cmdq.c b/drivers/soc/mediatek/mtk-cmdq.c
index d032603..35b791eb2 100644
--- a/drivers/soc/mediatek/mtk-cmdq.c
+++ b/drivers/soc/mediatek/mtk-cmdq.c
@@ -32,6 +32,7 @@
#include <linux/spinlock.h>
#include <linux/suspend.h>
#include <linux/timer.h>
+#include <linux/workqueue.h>
#include <soc/mediatek/cmdq.h>

#define CMDQ_THR_MAX_COUNT 3 /* main, sub, general(misc) */
@@ -132,10 +133,16 @@ struct cmdq_task {
struct cmdq_task_cb cb;
};

+struct cmdq_clk_release {
+ struct cmdq *cmdq;
+ struct work_struct release_work;
+};
+
struct cmdq {
struct mbox_controller mbox;
void __iomem *base;
u32 irq;
+ struct workqueue_struct *clk_release_wq;
struct cmdq_thread thread[CMDQ_THR_MAX_COUNT];
struct mutex task_mutex;
struct clk *clock;
@@ -301,11 +308,19 @@ static void cmdq_thread_wait_end(struct cmdq_thread *thread,
static void cmdq_task_exec(struct cmdq_task *task, struct cmdq_thread *thread)
{
struct cmdq *cmdq = task->cmdq;
- unsigned long curr_pa, end_pa;
+ unsigned long curr_pa, end_pa, flags;

task->thread = thread;
if (list_empty(&thread->task_busy_list)) {
- WARN_ON(clk_enable(cmdq->clock) < 0);
+ /*
+ * Unlock for clk prepare (sleeping function).
+ * We are safe to do that since we have task_mutex and
+ * only flush will add task.
+ */
+ spin_unlock_irqrestore(&thread->chan->lock, flags);
+ WARN_ON(clk_prepare_enable(cmdq->clock) < 0);
+ spin_lock_irqsave(&thread->chan->lock, flags);
+
WARN_ON(cmdq_thread_reset(cmdq, thread) < 0);

writel(task->pa_base, thread->base + CMDQ_THR_CURR_ADDR);
@@ -387,6 +402,26 @@ static void cmdq_task_handle_error(struct cmdq_task *task)
cmdq_thread_resume(thread);
}

+static void cmdq_clk_release_work(struct work_struct *work_item)
+{
+ struct cmdq_clk_release *clk_release = container_of(work_item,
+ struct cmdq_clk_release, release_work);
+ struct cmdq *cmdq = clk_release->cmdq;
+
+ clk_disable_unprepare(cmdq->clock);
+ kfree(clk_release);
+}
+
+static void cmdq_clk_release_schedule(struct cmdq *cmdq)
+{
+ struct cmdq_clk_release *clk_release;
+
+ clk_release = kmalloc(sizeof(*clk_release), GFP_ATOMIC);
+ clk_release->cmdq = cmdq;
+ INIT_WORK(&clk_release->release_work, cmdq_clk_release_work);
+ queue_work(cmdq->clk_release_wq, &clk_release->release_work);
+}
+
static void cmdq_thread_irq_handler(struct cmdq *cmdq,
struct cmdq_thread *thread)
{
@@ -436,7 +471,7 @@ static void cmdq_thread_irq_handler(struct cmdq *cmdq,

if (list_empty(&thread->task_busy_list)) {
cmdq_thread_disable(cmdq, thread);
- clk_disable(cmdq->clock);
+ cmdq_clk_release_schedule(cmdq);
} else {
mod_timer(&thread->timeout,
jiffies + msecs_to_jiffies(CMDQ_TIMEOUT_MS));
@@ -495,7 +530,7 @@ static void cmdq_thread_handle_timeout(unsigned long data)

cmdq_thread_resume(thread);
cmdq_thread_disable(cmdq, thread);
- clk_disable(cmdq->clock);
+ cmdq_clk_release_schedule(cmdq);
spin_unlock_irqrestore(&thread->chan->lock, flags);
}

@@ -783,7 +818,7 @@ static int cmdq_suspend(struct device *dev)
msleep(20);
}

- clk_unprepare(cmdq->clock);
+ flush_workqueue(cmdq->clk_release_wq);
return 0;
}

@@ -791,7 +826,6 @@ static int cmdq_resume(struct device *dev)
{
struct cmdq *cmdq = dev_get_drvdata(dev);

- WARN_ON(clk_prepare(cmdq->clock) < 0);
cmdq->suspended = false;
return 0;
}
@@ -800,8 +834,8 @@ static int cmdq_remove(struct platform_device *pdev)
{
struct cmdq *cmdq = platform_get_drvdata(pdev);

+ destroy_workqueue(cmdq->clk_release_wq);
mbox_controller_unregister(&cmdq->mbox);
- clk_unprepare(cmdq->clock);
return 0;
}

@@ -919,8 +953,13 @@ static int cmdq_probe(struct platform_device *pdev)
}

mutex_init(&cmdq->task_mutex);
+
+ cmdq->clk_release_wq = alloc_ordered_workqueue(
+ "%s", WQ_MEM_RECLAIM | WQ_HIGHPRI,
+ "cmdq_clk_release");
+
platform_set_drvdata(pdev, cmdq);
- WARN_ON(clk_prepare(cmdq->clock) < 0);
+
return 0;
}

--
1.9.1
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