[PATCH v3 1/3] clk: ti: add a usecount for autoidle

Andreas Kemnade
2019-01-16T22:04:47Z

Multiple users might deny autoidle on a clock. So we should have some
counting here, also according to the comment in _setup_iclk_autoidle().
Also setting autoidle regs is not atomic, so there is another reason
for locking.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
Change since v2:
- rebase on top of clk: ti: get rid of CLK_IS_BASIC
Changes since v1:
- use spinlocks instead of mutexes
- invert logic
drivers/clk/ti/autoidle.c | 32 ++++++++++++++++++++++++++++----
include/linux/clk/ti.h | 1 +
2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
index a129b4b36ea3..964e97b5478a 100644
--- a/drivers/clk/ti/autoidle.c
+++ b/drivers/clk/ti/autoidle.c
@@ -36,17 +36,41 @@ struct clk_ti_autoidle {

static LIST_HEAD(autoidle_clks);

+/*
+ * we have some non-atomic read/write
+ * operations behind it, so lets
+ * take one lock for handling autoidle
+ * of all clocks
+ */
+static DEFINE_SPINLOCK(autoidle_spinlock);
+
static int _omap2_clk_deny_idle(struct clk_hw_omap *clk)
{
- if (clk->ops && clk->ops->deny_idle)
- clk->ops->deny_idle(clk);
+ if (clk->ops && clk->ops->deny_idle) {
+ unsigned long irqflags;
+
+ spin_lock_irqsave(&autoidle_spinlock, irqflags);
+ clk->autoidle_count++;
+ if (clk->autoidle_count == 1)
+ clk->ops->deny_idle(clk);
+
+ spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
+ }
return 0;
}

static int _omap2_clk_allow_idle(struct clk_hw_omap *clk)
{
- if (clk->ops && clk->ops->allow_idle)
- clk->ops->allow_idle(clk);
+ if (clk->ops && clk->ops->allow_idle) {
+ unsigned long irqflags;
+
+ spin_lock_irqsave(&autoidle_spinlock, irqflags);
+ clk->autoidle_count--;
+ if (clk->autoidle_count == 0)
+ clk->ops->allow_idle(clk);
+
+ spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
+ }
return 0;
}

diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index eacc5df57b99..78872efc7be0 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -160,6 +160,7 @@ struct clk_hw_omap {
struct clockdomain *clkdm;
const struct clk_hw_omap_ops *ops;
u32 context;
+ int autoidle_count;
};

/*
--
2.11.0