[PATCH v16 5/5] CMDQ: save energy

From: HS Liao
Date: Tue Nov 01 2016 - 07:29:54 EST


use clk_disable_unprepare instead of clk_disable to save more energy
when CMDQ is idle.

Signed-off-by: HS Liao <hs.liao@xxxxxxxxxxxx>
---
drivers/mailbox/mtk-cmdq-mailbox.c | 52 ++++++++++++++++++++++++++++++++------
1 file changed, 44 insertions(+), 8 deletions(-)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index 747bcd3..8771e57 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c
@@ -22,6 +22,7 @@
#include <linux/mailbox_controller.h>
#include <linux/mailbox/mtk-cmdq-mailbox.h>
#include <linux/timer.h>
+#include <linux/workqueue.h>

#define CMDQ_THR_MAX_COUNT 3 /* main, sub, general(misc) */
#define CMDQ_OP_CODE_MASK (0xff << CMDQ_OP_CODE_SHIFT)
@@ -75,10 +76,16 @@ struct cmdq_task {
struct cmdq_pkt *pkt; /* the packet sent from mailbox client */
};

+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 clk *clock;
bool suspended;
@@ -203,7 +210,7 @@ static void cmdq_task_exec(struct cmdq_pkt *pkt, struct cmdq_thread *thread)
{
struct cmdq *cmdq;
struct cmdq_task *task;
- unsigned long curr_pa, end_pa;
+ unsigned long curr_pa, end_pa, flags;

cmdq = dev_get_drvdata(thread->chan->mbox->dev);

@@ -219,7 +226,14 @@ static void cmdq_task_exec(struct cmdq_pkt *pkt, struct cmdq_thread *thread)
task->pkt = pkt;

if (list_empty(&thread->task_busy_list)) {
- WARN_ON(clk_enable(cmdq->clock) < 0);
+ /*
+ * Unlock for clk prepare (sleeping function).
+ * This is safe since clk_prepare_enable has internal locks.
+ */
+ 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);
@@ -301,6 +315,26 @@ 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)
{
@@ -350,7 +384,7 @@ 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));
@@ -409,7 +443,7 @@ 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);
}

@@ -433,7 +467,7 @@ static int cmdq_suspend(struct device *dev)
if (task_running)
dev_warn(dev, "exist running task(s) in suspend\n");

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

@@ -441,7 +475,6 @@ 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;
}
@@ -450,8 +483,8 @@ 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;
}

@@ -567,8 +600,11 @@ static int cmdq_probe(struct platform_device *pdev)
return err;
}

+ 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