msm: clock: Move voltage scaling to prepare/unprepare
Move the voltage calls to a sleepable context so we can avoid
spinning for hundreds of microseconds with interrupts disabled
waiting for a regulator to increase. This change also paves the
way to making the clock driver into a real regulator consumer
that uses the proper regulator APIs instead of the MSM specific
rpm_vreg API.
Doing this also requires us to make clk_set_rate() a sleeping
call so that concurrent clk_prepare() and clk_set_rate() calls
are synchronized. Making clk_set_rate() sleepable also
necessitates moving the clk_set_rate() call in clock-voter.c to a
sleepable context. Do that by having clock-voter aggregate and
update the rate in prepare/unprepare instead of enable/disable
(note that enable/disable of voter clocks implicitly calls
enable/disable on the parent via generic clock code).
Now that clk_set_rate() is sleeping, call clk_prepare() and
clk_unprepare() in the clock-local code when a rate change
requires reparenting the clock. This cleans up a problem we have
where sources may be left unprepared by a clock rate switch
(hence the default true warned flag for PLLs and crystals).
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
(cherry picked from commit d86d1f2d968f194e3db46bb683e370a9fa3a6037)
Conflicts:
arch/arm/mach-msm/clock-local2.c
Change-Id: Ie5bbb17537d5b33de92f8ea1c2da6070b18c14f1
Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>
diff --git a/arch/arm/mach-msm/clock-local.c b/arch/arm/mach-msm/clock-local.c
index 2df1cd1..b952f2f 100644
--- a/arch/arm/mach-msm/clock-local.c
+++ b/arch/arm/mach-msm/clock-local.c
@@ -320,10 +320,6 @@
u32 reg_val;
void __iomem *const reg = rcg->b.ctl_reg;
- WARN(rcg->current_freq == &rcg_dummy_freq,
- "Attempting to enable %s before setting its rate. "
- "Set the rate first!\n", rcg->c.dbg_name);
-
/*
* Program the NS register, if applicable. NS registers are not
* set in the set_rate path because power can be saved by deferring
@@ -419,6 +415,18 @@
}
}
+static int rcg_clk_prepare(struct clk *c)
+{
+ struct rcg_clk *rcg = to_rcg_clk(c);
+
+ WARN(rcg->current_freq == &rcg_dummy_freq,
+ "Attempting to prepare %s before setting its rate. "
+ "Set the rate first!\n", rcg->c.dbg_name);
+ rcg->prepared = true;
+
+ return 0;
+}
+
/* Enable a rate-settable clock. */
static int rcg_clk_enable(struct clk *c)
{
@@ -445,6 +453,12 @@
spin_unlock_irqrestore(&local_clock_reg_lock, flags);
}
+static void rcg_clk_unprepare(struct clk *c)
+{
+ struct rcg_clk *rcg = to_rcg_clk(c);
+ rcg->prepared = false;
+}
+
/*
* Frequency-related functions
*/
@@ -456,6 +470,7 @@
struct clk_freq_tbl *nf, *cf;
struct clk *chld;
int rc = 0;
+ unsigned long flags;
for (nf = rcg->freq_tbl; nf->freq_hz != FREQ_END
&& nf->freq_hz != rate; nf++)
@@ -466,11 +481,22 @@
cf = rcg->current_freq;
- if (rcg->enabled) {
- /* Enable source clock dependency for the new freq. */
- rc = clk_enable(nf->src_clk);
+ /* Enable source clock dependency for the new frequency */
+ if (rcg->prepared) {
+ rc = clk_prepare(nf->src_clk);
if (rc)
return rc;
+
+ }
+
+ spin_lock_irqsave(&c->lock, flags);
+ if (rcg->enabled) {
+ rc = clk_enable(nf->src_clk);
+ if (rc) {
+ spin_unlock_irqrestore(&c->lock, flags);
+ clk_unprepare(nf->src_clk);
+ return rc;
+ }
}
spin_lock(&local_clock_reg_lock);
@@ -519,6 +545,10 @@
/* Release source requirements of the old freq. */
if (rcg->enabled)
clk_disable(cf->src_clk);
+ spin_unlock_irqrestore(&c->lock, flags);
+
+ if (rcg->prepared)
+ clk_unprepare(cf->src_clk);
return rc;
}
@@ -819,8 +849,10 @@
}
struct clk_ops clk_ops_rcg = {
+ .prepare = rcg_clk_prepare,
.enable = rcg_clk_enable,
.disable = rcg_clk_disable,
+ .unprepare = rcg_clk_unprepare,
.enable_hwcg = rcg_clk_enable_hwcg,
.disable_hwcg = rcg_clk_disable_hwcg,
.in_hwcg_mode = rcg_clk_in_hwcg_mode,