[EFR32] Change Matter NVM3 reserved keys range (project-chip#17059)

* Change Region and Sub region for matter nvm3 storage

* add nvm3 key reserved range checks

src/platform/EFR32/EFR32Config.cpp

@@ -500,8 +500,10 @@ exit:;
 
 bool EFR32Config::ValidConfigKey(Key key)
 {
-    // Returns true if the key is in the valid Matter Config nvm3 key range.
-    if ((key >= kMinConfigKey_MatterFactory) && (key <= kMaxConfigKey_MatterKvs))
+    // Returns true if the key is in the Matter nvm3 reserved key range.
+    // Additional check validates that the user consciously defined the expected key range
+    if ((key >= kMatterNvm3KeyLoLimit) && (key <= kMatterNvm3KeyHiLimit) && (key >= kMinConfigKey_MatterFactory) &&
+        (key <= kMaxConfigKey_MatterKvs))
     {
         return true;
     }

src/platform/EFR32/EFR32Config.h

@@ -56,11 +56,14 @@ namespace Internal {
 // Silabs NVM3 objects use a 20-bit number,
 // NVM3 Key 19:16 Stack region
 // NVM3 Key 15:0 Available NVM3 keys 0x0000 -> 0xFFFF.
-// e.g. key = 0x0AA201
-// '0A' = Matter nvm3 region
-// 'A2' = the nv group base offest (Factory, Config or Counter)
+// Matter stack reserved region ranges from 0x087200 to 0x087FFF
+// e.g. key = 0x087201
+// '08' = Matter nvm3 region
+// '72' = the sub region group base offset (Factory, Config, Counter or KVS)
 // '01' = the id offset inside the group.
-constexpr uint32_t kMatterNvm3KeyDomain = 0x0A0000U;
+constexpr uint32_t kMatterNvm3KeyDomain  = 0x080000U;
+constexpr uint32_t kMatterNvm3KeyLoLimit = 0x087200U; // Do not modify without Silabs GSDK team approval
+constexpr uint32_t kMatterNvm3KeyHiLimit = 0x087FFFU; // Do not modify without Silabs GSDK team approval
 constexpr inline uint32_t EFR32ConfigKey(uint8_t keyBaseOffset, uint8_t id)
 {
     return kMatterNvm3KeyDomain | static_cast<uint32_t>(keyBaseOffset) << 8 | id;
@@ -74,14 +77,15 @@ class EFR32Config
     using Key = uint32_t;
 
     // NVM3 key base offsets used by the CHIP Device Layer.
+    // ** Key base can range from 0x72 to 0x7F **
     // Persistent config values set at manufacturing time. Retained during factory reset.
-    static constexpr uint8_t kMatterFactory_KeyBase = 0xA2;
+    static constexpr uint8_t kMatterFactory_KeyBase = 0x72;
     // Persistent config values set at runtime. Cleared during factory reset.
-    static constexpr uint8_t kMatterConfig_KeyBase = 0xA3;
+    static constexpr uint8_t kMatterConfig_KeyBase = 0x73;
     // Persistent counter values set at runtime. Retained during factory reset.
-    static constexpr uint8_t kMatterCounter_KeyBase = 0xA4;
+    static constexpr uint8_t kMatterCounter_KeyBase = 0x74;
     // Persistent config values set at runtime. Cleared during factory reset.
-    static constexpr uint8_t kMatterKvs_KeyBase = 0xA5;
+    static constexpr uint8_t kMatterKvs_KeyBase = 0x75;
 
     // Key definitions for well-known configuration values.
     // Factory config keys