ARM: OMAP2+: clockdomain: bypass clockdomain handling when disabling unused clks
The OMAP port to the common clk framework[1] resulted in spurious WARNs
while disable unused clocks. This is due to _clkdm_clk_hwmod_disable
catching clkdm->usecount's with a value of zero. Even less desirable it
would not allow the clkdm_clk_disable function pointer to get called due
to an early return of -ERANGE.
This patch adds a check for such a corner case by skipping the WARN and
early return in the event that clkdm->usecount and clk->enable_usecount
are both zero. Presumably this could only happen during the check for
unused clocks at boot-time.
[1] http://article.gmane.org/gmane.linux.ports.arm.omap/88824
Signed-off-by: Mike Turquette <mturquette@ti.com>
[paul@pwsan.com: split the hwmod and clock disable cases; modified the
code to skip the clockdomain handling during the disable-unused-clocks phase;
added COMMON_CLK ifdef; removed include of clk-private.h at Mike's request]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
index 64e5046..be6fe35 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -22,6 +22,7 @@
#include <linux/clk.h>
#include <linux/limits.h>
#include <linux/err.h>
+#include <linux/clk-provider.h>
#include <linux/io.h>
@@ -947,35 +948,6 @@
return 0;
}
-static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
-{
- unsigned long flags;
-
- if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
- return -EINVAL;
-
- spin_lock_irqsave(&clkdm->lock, flags);
-
- if (atomic_read(&clkdm->usecount) == 0) {
- spin_unlock_irqrestore(&clkdm->lock, flags);
- WARN_ON(1); /* underflow */
- return -ERANGE;
- }
-
- if (atomic_dec_return(&clkdm->usecount) > 0) {
- spin_unlock_irqrestore(&clkdm->lock, flags);
- return 0;
- }
-
- arch_clkdm->clkdm_clk_disable(clkdm);
- pwrdm_state_switch(clkdm->pwrdm.ptr);
- spin_unlock_irqrestore(&clkdm->lock, flags);
-
- pr_debug("clockdomain: %s: disabled\n", clkdm->name);
-
- return 0;
-}
-
/**
* clkdm_clk_enable - add an enabled downstream clock to this clkdm
* @clkdm: struct clockdomain *
@@ -1018,15 +990,41 @@
*/
int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
{
- /*
- * XXX Rewrite this code to maintain a list of enabled
- * downstream clocks for debugging purposes?
- */
+ unsigned long flags;
- if (!clk)
+ if (!clkdm || !clk || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
return -EINVAL;
- return _clkdm_clk_hwmod_disable(clkdm);
+ spin_lock_irqsave(&clkdm->lock, flags);
+
+#ifdef CONFIG_COMMON_CLK
+ /* corner case: disabling unused clocks */
+ if (__clk_get_enable_count(clk) == 0)
+ goto ccd_exit;
+#endif
+
+ if (atomic_read(&clkdm->usecount) == 0) {
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+ WARN_ON(1); /* underflow */
+ return -ERANGE;
+ }
+
+ if (atomic_dec_return(&clkdm->usecount) > 0) {
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+ return 0;
+ }
+
+ arch_clkdm->clkdm_clk_disable(clkdm);
+ pwrdm_state_switch(clkdm->pwrdm.ptr);
+
+ pr_debug("clockdomain: %s: disabled\n", clkdm->name);
+
+#ifdef CONFIG_COMMON_CLK
+ccd_exit:
+#endif
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+
+ return 0;
}
/**
@@ -1077,6 +1075,8 @@
*/
int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
{
+ unsigned long flags;
+
/* The clkdm attribute does not exist yet prior OMAP4 */
if (cpu_is_omap24xx() || cpu_is_omap34xx())
return 0;
@@ -1086,9 +1086,28 @@
* downstream hwmods for debugging purposes?
*/
- if (!oh)
+ if (!clkdm || !oh || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
return -EINVAL;
- return _clkdm_clk_hwmod_disable(clkdm);
+ spin_lock_irqsave(&clkdm->lock, flags);
+
+ if (atomic_read(&clkdm->usecount) == 0) {
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+ WARN_ON(1); /* underflow */
+ return -ERANGE;
+ }
+
+ if (atomic_dec_return(&clkdm->usecount) > 0) {
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+ return 0;
+ }
+
+ arch_clkdm->clkdm_clk_disable(clkdm);
+ pwrdm_state_switch(clkdm->pwrdm.ptr);
+ spin_unlock_irqrestore(&clkdm->lock, flags);
+
+ pr_debug("clockdomain: %s: disabled\n", clkdm->name);
+
+ return 0;
}