Hi Kevin,
working my way through these...
On Thu, 9 Dec 2010, Kevin Hilman wrote:
Add new powerdomain API
int pwrdm_get_context_loss_count(struct powerdomain *pwrdm)
for checking how many times the powerdomain has lost context. The
loss count is the sum sum of the powerdomain off-mode counter, the
logic off counter and the per-bank memory off counter.
Cc: Paul Walmsley p...@pwsan.com
Signed-off-by: Kevin Hilman khil...@deeprootsystems.com
---
arch/arm/mach-omap2/powerdomain.c | 23 +++
arch/arm/mach-omap2/powerdomain.h |1 +
2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/powerdomain.c
b/arch/arm/mach-omap2/powerdomain.c
index 06ef60e..78e7d22 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -909,3 +909,26 @@ int pwrdm_post_transition(void)
pwrdm_for_each(_pwrdm_post_transition_cb, NULL);
return 0;
}
+
+/**
+ * pwrdm_get_context_loss_count - get powerdomain's context loss count
+ * @pwrdm: struct powerdomain * to wait for
+ *
+ * Context loss count is a sum of powerdomain off-mode counter,
+ * the logic off counter and the per-bank memory off counter.
+ */
+int pwrdm_get_context_loss_count(struct powerdomain *pwrdm)
+{
+ int i, count;
There should be a test here to prevent a null pointer deref if pwrdm is
NULL.
+
+ count = pwrdm-state_counter[PWRDM_POWER_OFF];
+ count += pwrdm-ret_logic_off_counter;
+
+ for (i = 0; i pwrdm-banks; i++)
+ count += pwrdm-ret_mem_off_counter[i];
Looks like these state counters are unsigned ints. So they could easily
overflow count when they are summed. This is probably not a major problem
as far as this function is concerned, but the next patch can return
-ENODEV upon error, which, if this function were really unlucky, it could
effectively return -ENODEV.
It would be good to constrain the minimum successful return value of this
function to 0. This will require some creativity since the function
shouldn't just return 0 for all sums that wrap around and wind up
negative; the return value should still continue to differ from the value
when it was called previously. Otherwise devices might not restore their
context when they should.
+
+ pr_debug(powerdomain: %s: context loss count = %u\n,
+ pwrdm-name, count);
+
+ return count;
+}
diff --git a/arch/arm/mach-omap2/powerdomain.h
b/arch/arm/mach-omap2/powerdomain.h
index 35b5b48..d269eff 100644
--- a/arch/arm/mach-omap2/powerdomain.h
+++ b/arch/arm/mach-omap2/powerdomain.h
@@ -211,6 +211,7 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
int pwrdm_pre_transition(void);
int pwrdm_post_transition(void);
int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
+int pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
extern void omap2xxx_powerdomains_init(void);
extern void omap3xxx_powerdomains_init(void);
Also, as we discussed privately, there is at least one bug in the counters
where the logic-off and membank-off counters don't increment correctly
when the entire powerdomain is off. But that problem does not have to be
dealt with as part of this series...
- Paul
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