From 98871e58af27dee3b5d02232246775e6843599b5 Mon Sep 17 00:00:00 2001
From: SPRESENSE <41312067+SPRESENSE@users.noreply.github.com>
Date: Wed, 19 May 2021 17:04:22 +0900
Subject: [PATCH] arch: cxd56xx: Fix gnss open error by clock change

If the system clock is changed during loading gnssfw, gnss open may be
failed. So this commit prohibits clock change until loading gnssfw is
completed.
---
 arch/arm/src/cxd56xx/cxd56_gnss.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm/src/cxd56xx/cxd56_gnss.c b/arch/arm/src/cxd56xx/cxd56_gnss.c
index 8325b89aa0b..13c739abaed 100644
--- a/arch/arm/src/cxd56xx/cxd56_gnss.c
+++ b/arch/arm/src/cxd56xx/cxd56_gnss.c
@@ -389,6 +389,11 @@ static struct pm_cpu_freqlock_s g_lv_lock =
   PM_CPUFREQLOCK_INIT(PM_CPUFREQLOCK_TAG('G', 'T', 0),
                       PM_CPUFREQLOCK_FLAG_LV);
 
+/* Lock to prohibit clock change in gnss open */
+
+static struct pm_cpu_freqlock_s g_hold_lock =
+  PM_CPUFREQLOCK_INIT(0, PM_CPUFREQLOCK_FLAG_HOLD);
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -2632,7 +2637,16 @@ static int cxd56_gnss_open(FAR struct file *filep)
 
       nxsem_set_protocol(&priv->syncsem, SEM_PRIO_NONE);
 
+      /* Prohibit the clock change during loading image */
+
+      up_pm_acquire_freqlock(&g_hold_lock);
+
       ret = fw_pm_loadimage(CXD56_GNSS_GPS_CPUID, CXD56_GNSS_FWNAME);
+
+      /* Allow the clock change after loading image */
+
+      up_pm_release_freqlock(&g_hold_lock);
+
       if (ret < 0)
         {
           goto _err1;