[incubator-nuttx] 02/21: arch: cxd56xx: Support for suppresion of clock change

[jerpelea]

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jerpelea pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git

commit db340a8941769712bc5e2b93d0aae1ca48628243
Author: SPRESENSE <41312067+sprese...@users.noreply.github.com>
AuthorDate: Wed May 19 17:03:49 2021 +0900

    arch: cxd56xx: Support for suppresion of clock change
    
    Introduce PM_CPUFREQLOCK_FLAG_HOLD into the frequency lock mechanism in
    power manager, which is used to keep the current frequency without clock
    change, for example, during the transfer of a periphral.
---
 arch/arm/include/cxd56xx/pm.h         |  5 +++--
 arch/arm/src/cxd56xx/cxd56_powermgr.c | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/cxd56xx/pm.h b/arch/arm/include/cxd56xx/pm.h
index 824a0a3..fe3ab71 100644
--- a/arch/arm/include/cxd56xx/pm.h
+++ b/arch/arm/include/cxd56xx/pm.h
@@ -62,8 +62,9 @@
 
 /* FrequencyLock request flag definitions */
 
-#define PM_CPUFREQLOCK_FLAG_HV (0x0001) /* request HV */
-#define PM_CPUFREQLOCK_FLAG_LV (0x4000) /* request LV */
+#define PM_CPUFREQLOCK_FLAG_HV (0x0001)   /* request HV */
+#define PM_CPUFREQLOCK_FLAG_LV (0x4000)   /* request LV */
+#define PM_CPUFREQLOCK_FLAG_HOLD (0x8000) /* hold the current frequency */
 
 /* FrequencyLock identifier tag helper macro function */
 
diff --git a/arch/arm/src/cxd56xx/cxd56_powermgr.c 
b/arch/arm/src/cxd56xx/cxd56_powermgr.c
index 489216a..00acf5f 100644
--- a/arch/arm/src/cxd56xx/cxd56_powermgr.c
+++ b/arch/arm/src/cxd56xx/cxd56_powermgr.c
@@ -577,6 +577,13 @@ void up_pm_acquire_freqlock(struct pm_cpu_freqlock_s *lock)
 
   cxd56_pm_semtake(&g_freqlock);
 
+  if (lock->flag == PM_CPUFREQLOCK_FLAG_HOLD)
+    {
+      /* Return with holding the current frequency */
+
+      return;
+    }
+
   for (entry = sq_peek(&g_freqlockqueue); entry; entry = sq_next(entry))
     {
       if (entry == (struct sq_entry_s *)lock)
@@ -616,6 +623,13 @@ void up_pm_release_freqlock(struct pm_cpu_freqlock_s *lock)
 
   DEBUGASSERT(lock);
 
+  if (lock->flag == PM_CPUFREQLOCK_FLAG_HOLD)
+    {
+      /* Release holding the current frequency */
+
+      goto exit;
+    }
+
   up_pm_acquire_wakelock(&g_wlock);
 
   cxd56_pm_semtake(&g_freqlock);
@@ -634,6 +648,7 @@ void up_pm_release_freqlock(struct pm_cpu_freqlock_s *lock)
         }
     }
 
+exit:
   nxsem_post(&g_freqlock);
 
   up_pm_release_wakelock(&g_wlock);