Re: [PATCH RFC 1/2] clk: ti: add a usecount for autoidle

Tero Kristo <t-kristo@xxxxxx> · Thu, 4 Oct 2018 17:40:06 +0300

On 04/10/18 08:51, Andreas Kemnade wrote:
We have the scenario that first autoidle is disabled for all clocks,
then it is disabled for selected ones and then enabled for all. So
we should have some counting here, also according to the
comment in  _setup_iclk_autoidle()

Signed-off-by: Andreas Kemnade <andreas@xxxxxxxxxxxx>
---
  drivers/clk/ti/autoidle.c | 20 ++++++++++++--------
  include/linux/clk/ti.h    |  1 +
  2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
index 7bb9afbe4058..be2ce42e4f33 100644
--- a/drivers/clk/ti/autoidle.c
+++ b/drivers/clk/ti/autoidle.c
@@ -48,8 +48,11 @@ int omap2_clk_deny_idle(struct clk *clk)
  	struct clk_hw_omap *c;
  
  	c = to_clk_hw_omap(__clk_get_hw(clk));
-	if (c->ops && c->ops->deny_idle)
-		c->ops->deny_idle(c);
+	if (c->ops && c->ops->deny_idle) {
+		c->autoidle_count--;
+		if (c->autoidle_count == -1)
+			c->ops->deny_idle(c);

This code is racy as you have no locking in place. Please fix.

Also, this should be verified that it doesn't cause any PM regressions, 
I hope you have done that?

-Tero

+	}
  	return 0;
  }
  
@@ -64,8 +67,11 @@ int omap2_clk_allow_idle(struct clk *clk)
  	struct clk_hw_omap *c;
  
  	c = to_clk_hw_omap(__clk_get_hw(clk));
-	if (c->ops && c->ops->allow_idle)
-		c->ops->allow_idle(c);
+	if (c->ops && c->ops->allow_idle) {
+		c->autoidle_count++;
+		if (c->autoidle_count == 0)
+			c->ops->allow_idle(c);
+	}
  	return 0;
  }
  
@@ -201,8 +207,7 @@ int omap2_clk_enable_autoidle_all(void)
  	struct clk_hw_omap *c;
  
  	list_for_each_entry(c, &clk_hw_omap_clocks, node)
-		if (c->ops && c->ops->allow_idle)
-			c->ops->allow_idle(c);
+		omap2_clk_allow_idle(c->hw.clk);
  
  	_clk_generic_allow_autoidle_all();
  
@@ -223,8 +228,7 @@ int omap2_clk_disable_autoidle_all(void)
  	struct clk_hw_omap *c;
  
  	list_for_each_entry(c, &clk_hw_omap_clocks, node)
-		if (c->ops && c->ops->deny_idle)
-			c->ops->deny_idle(c);
+		omap2_clk_deny_idle(c->hw.clk);
  
  	_clk_generic_deny_autoidle_all();
  
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index a8faa38b1ed6..c460355419c0 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -159,6 +159,7 @@ struct clk_hw_omap {
  	const char		*clkdm_name;
  	struct clockdomain	*clkdm;
  	const struct clk_hw_omap_ops	*ops;
+	int autoidle_count;
  };
  
  /*


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