Re: [RESEND PATCH 2/2] soc: qcom: rpmhpd: Make power_on actually enable the domain

From: Rajendra Nayak
Date: Thu Jul 15 2021 - 08:24:56 EST



On 7/15/2021 5:46 PM, Sibi Sankar wrote:
Hey Bjorn,

Thanks for the patch.

On 2021-07-03 08:24, Bjorn Andersson wrote:
The general expectation is that powering on a power-domain should make
the power domain deliver some power, and if a specific performace state

s/performace/performance/

is needed further requests has to be made.

But in contrast with other power-domain implementations (e.g. rpmpd) the
RPMh does not have an interface to enable the power, so the driver has
to vote for a particular corner (performance level) in rpmh_power_on().

But the corner is never initialized, so a typical request to simply
enable the power domain would not actually turn on the hardware. Further
more, when no more clients vote for a performance state (i.e. the
aggregated vote is 0) the power domain would be turn off.

Fix both of these issues by always voting for a corner with non-zero
value, when the power domain is enabled.

The tracking of the lowest non-zero corner is performed to handle the
corner case if there's ever a domain with a non-zero lowest corner, in
which case both rpmh_power_on() and rpmh_rpmhpd_set_performance_state()
would be allowed to use this lowest corner.

Fixes: 279b7e8a62cc ("soc: qcom: rpmhpd: Add RPMh power domain driver")
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---

Resending because the hunk in rpmhpd_update_level_mapping() was left in the
index.

 drivers/soc/qcom/rpmhpd.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/rpmhpd.c b/drivers/soc/qcom/rpmhpd.c
index fa209b479ab3..76ea6b053ef0 100644
--- a/drivers/soc/qcom/rpmhpd.c
+++ b/drivers/soc/qcom/rpmhpd.c
@@ -30,6 +30,7 @@
  * @active_only:    True if it represents an Active only peer
  * @corner:        current corner
  * @active_corner:    current active corner
+ * @enable_corner:    lowest non-zero corner
  * @level:        An array of level (vlvl) to corner (hlvl) mappings
  *            derived from cmd-db
  * @level_count:    Number of levels supported by the power domain. max
@@ -47,6 +48,7 @@ struct rpmhpd {
     const bool    active_only;
     unsigned int    corner;
     unsigned int    active_corner;
+    unsigned int    enable_corner;
     u32        level[RPMH_ARC_MAX_LEVELS];
     size_t        level_count;
     bool        enabled;
@@ -385,13 +387,13 @@ static int rpmhpd_aggregate_corner(struct rpmhpd
*pd, unsigned int corner)
 static int rpmhpd_power_on(struct generic_pm_domain *domain)
 {
     struct rpmhpd *pd = domain_to_rpmhpd(domain);
-    int ret = 0;
+    unsigned int corner;
+    int ret;

     mutex_lock(&rpmhpd_lock);

-    if (pd->corner)
-        ret = rpmhpd_aggregate_corner(pd, pd->corner);
-
+    corner = max(pd->corner, pd->enable_corner);
+    ret = rpmhpd_aggregate_corner(pd, corner);
     if (!ret)
         pd->enabled = true;

@@ -436,6 +438,10 @@ static int rpmhpd_set_performance_state(struct
generic_pm_domain *domain,
         i--;

     if (pd->enabled) {
+        /* Ensure that the domain isn't turn off */
+        if (i < pd->enable_corner)
+            i = pd->enable_corner;
+
         ret = rpmhpd_aggregate_corner(pd, i);
         if (ret)
             goto out;
@@ -472,6 +478,10 @@ static int rpmhpd_update_level_mapping(struct
rpmhpd *rpmhpd)
     for (i = 0; i < rpmhpd->level_count; i++) {
         rpmhpd->level[i] = buf[i];

+        /* Remember the first non-zero corner */

Shouldn't we be tracking the corner that
corresponds to the first non-zero level
instead?

Thats correct, thanks for spotting this, the first non-zero
corner is always 1 :)


+        if (!rpmhpd->enable_corner)
+            rpmhpd->enable_corner = i;
+
         /*
          * The AUX data may be zero padded.  These 0 valued entries at
          * the end of the map must be ignored.


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