For some hwmods (e.g. DCAN on DRA7) we need the possibility to
disable HW_AUTO for the clockdomain while the module is active.
To achieve this there needs to be a refcounting mechanism to
indicate whether any module in the clockdomain has requested
to disable HW_AUTO. We keep track of this in 'noidlecount'.
Hwmod code must use clkdm_hwmod_prevent_hwauto() to prevent
HW_AUTO of the clockdomain in the future clkdm_hwmod_hwauto() calls.
It must use clkdm_hwmod_allow_hwauto() to allow HW_AUTO in
the future clkdm_hwmod_hwauto() calls.
Hwmod code must use clkdm_hwmod_allow_hwauto() whenever it needs
to request HW_AUTO of any clockdomain. (Typically after it has
enabled the module).
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
arch/arm/mach-omap2/clockdomain.c | 71 +++++++++++++++++++++++++++++++++++++++
arch/arm/mach-omap2/clockdomain.h | 5 +++
2 files changed, 76 insertions(+)
diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
index 2da3b5e..a7190d2 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -1212,6 +1212,77 @@ ccd_exit:
return 0;
}
+/*
+ * prevent future hwauto for this clkdm. If clkdm->usecount becomes hwauto isn't prevented.
+ * It will only prevnt future hwauto but not bring it out of hwauto.
+ */
+int clkdm_hwmod_prevent_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh)
+{
+ /* The clkdm attribute does not exist yet prior OMAP4 */
+ if (cpu_is_omap24xx() || cpu_is_omap34xx())
+ return 0;
+
+ if (!clkdm || !oh || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
+ return -EINVAL;
+
+
+ pwrdm_lock(clkdm->pwrdm.ptr);
+ clkdm->noidlecount++;
+ pwrdm_unlock(clkdm->pwrdm.ptr);
+
+ return 0;
+}
+
+/*
+ * allow future hwauto for this clkdm
+ * It won't put clkdm into hwauto. use clkdm_hwmod_hwauto() for that.
+ */
+int clkdm_hwmod_allow_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh)
+{
+ /* The clkdm attribute does not exist yet prior OMAP4 */
+ if (cpu_is_omap24xx() || cpu_is_omap34xx())
+ return 0;
+
+ if (!clkdm || !oh || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
+ return -EINVAL;
+
+
+ pwrdm_lock(clkdm->pwrdm.ptr);
+
+ if (clkdm->noidlecount == 0) {
+ pwrdm_unlock(clkdm->pwrdm.ptr);
+ WARN_ON(1); /* underflow */
+ return -ERANGE;
+ }
+
+ clkdm->noidlecount--;
+ pwrdm_unlock(clkdm->pwrdm.ptr);
+
+ return 0;
+}
+
+/*
+ * put clkdm in hwauto if we can. checks noidlecount to see if we can.
+ */
+int clkdm_hwmod_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh)
+{
+ /* The clkdm attribute does not exist yet prior OMAP4 */
+ if (cpu_is_omap24xx() || cpu_is_omap34xx())
+ return 0;
+
+ if (!clkdm || !oh || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
+ return -EINVAL;
+
+
+ pwrdm_lock(clkdm->pwrdm.ptr);
+ if (clkdm->noidlecount == 0)
+ clkdm_allow_idle_nolock(clkdm);
+
+ pwrdm_unlock(clkdm->pwrdm.ptr);
+
+ return 0;
+}
+
/**
* clkdm_hwmod_enable - add an enabled downstream hwmod to this clkdm
* @clkdm: struct clockdomain *
diff --git a/arch/arm/mach-omap2/clockdomain.h b/arch/arm/mach-omap2/clockdomain.h
index 77bab5f..8c491be 100644
--- a/arch/arm/mach-omap2/clockdomain.h
+++ b/arch/arm/mach-omap2/clockdomain.h
@@ -114,6 +114,7 @@ struct omap_hwmod;
* @wkdep_srcs: Clockdomains that can be told to wake this powerdomain up
* @sleepdep_srcs: Clockdomains that can be told to keep this clkdm from inact
* @usecount: Usecount tracking
+ * @noidlecount: Noidle count tracking. Domain won't be auto idled this is > 0.
* @node: list_head to link all clockdomains together
*
* @prcm_partition should be a macro from mach-omap2/prcm44xx.h (OMAP4 only)
@@ -138,6 +139,7 @@ struct clockdomain {
struct clkdm_dep *wkdep_srcs;
struct clkdm_dep *sleepdep_srcs;
int usecount;
+ int noidlecount;
struct list_head node;
};
@@ -211,6 +213,9 @@ int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk);
int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk);
int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh);
int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh);
+int clkdm_hwmod_prevent_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh);
+int clkdm_hwmod_allow_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh);
+int clkdm_hwmod_hwauto(struct clockdomain *clkdm, struct omap_hwmod *oh);
extern void __init omap242x_clockdomains_init(void);
extern void __init omap243x_clockdomains_init(void);
--
2.1.4
--
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