change(esp_pm): improve POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP description

Rename PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP to PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
and improve the description for it

components/esp_hw_support/sleep_cpu.c

@@ -92,7 +92,7 @@ static DRAM_ATTR __attribute__((unused)) sleep_cpu_retention_t s_cpu_retention;
 
 #if SOC_PM_SUPPORT_TAGMEM_PD && SOC_PM_CPU_RETENTION_BY_RTCCNTL
 
-#if CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
+#if CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
 static uint32_t cache_tagmem_retention_setup(uint32_t code_seg_vaddr, uint32_t code_seg_size, uint32_t data_seg_vaddr, uint32_t data_seg_size)
 {
     uint32_t sets;   /* i/d-cache total set counts */
@@ -153,11 +153,11 @@ static uint32_t cache_tagmem_retention_setup(uint32_t code_seg_vaddr, uint32_t c
      * i/d-cache tagmem blocks (128 bits * 3 = 96 bits * 4) */
     return (((icache_tagmem_blk_gs + dcache_tagmem_blk_gs) << 2) * 3);
 }
-#endif // CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
+#endif // CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
 
 static esp_err_t esp_sleep_tagmem_pd_low_init(void)
 {
-#if CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
+#if CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
         if (s_cpu_retention.retent.tagmem.link_addr == NULL) {
             extern char _stext[], _etext[];
             uint32_t code_start = (uint32_t)_stext;
@@ -186,11 +186,11 @@ static esp_err_t esp_sleep_tagmem_pd_low_init(void)
                 return ESP_ERR_NO_MEM;
             }
         }
-#else // CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
+#else // CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
         s_cpu_retention.retent.tagmem.icache.enable = 0;
         s_cpu_retention.retent.tagmem.dcache.enable = 0;
         s_cpu_retention.retent.tagmem.link_addr = NULL;
-#endif // CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
+#endif // CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
     return ESP_OK;
 }
 

components/esp_pm/Kconfig

@@ -108,21 +108,31 @@ menu "Power Management"
     config PM_POWER_DOWN_CPU_IN_LIGHT_SLEEP
         bool "Power down CPU in light sleep"
         depends on SOC_PM_SUPPORT_CPU_PD
-        select PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP if ESP32S3_DATA_CACHE_16KB
+        select PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP if ESP32S3_DATA_CACHE_16KB
         default y
         help
-            If enabled, the CPU will be powered down in light sleep. On esp32c3 soc, enabling this
-            option will consume 1.68 KB of internal RAM and will reduce sleep current consumption
-            by about 100 uA. On esp32s3 soc, enabling this option will consume 8.58 KB of internal
-            RAM and will reduce sleep current consumption by about 650 uA.
+            If enabled, the CPU will be powered down in light sleep, ESP chips supports saving and restoring CPU's running
+            context before and after light sleep, the feature provides applications with seamless CPU powerdowned lightsleep
+            without user awareness.
+            But this will takes up some internal memory. On esp32c3 soc, enabling this option will consume 1.68 KB of internal
+            RAM and will reduce sleep current consumption by about 100 uA. On esp32s3 soc, enabling this option will consume
+            8.58 KB of internal RAM and will reduce sleep current consumption by about 650 uA.
 
-    config PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP
-        bool "Power down I/D-cache tag memory in light sleep"
+    config PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP
+        bool "Restore I/D-cache tag memory after power down CPU light sleep"
         depends on IDF_TARGET_ESP32S3 && PM_POWER_DOWN_CPU_IN_LIGHT_SLEEP
         default y
         help
-            If enabled, the I/D-cache tag memory will be retained in light sleep. Depending on the the
-            cache configuration, if this option is enabled, it will consume up to 9 KB of internal RAM.
+            Cache tag memory and CPU both belong to the CPU power domain. ESP chips supports saving and restoring Cache tag memory
+            before and after sleep, this feature supports accesses to the external memory that was cached before sleep still
+            be cached when the CPU wakes up from a powerdowned CPU lightsleep. This option controls the restore method for Cache
+            tag memory in lightsleep.
+            If this option is enabled, the I/D-cache tag memory will be backuped to the internal RAM before sleep and restored
+            upon wakeup. Depending on the the cache configuration, if this option is enabled, it will consume up to 9 KB
+            of internal RAM.
+            If this option is disabled, all cached data won't be kept after sleep, the DCache will be writeback before
+            sleep and invalid all cached data after sleep, all accesses to external memory(Flash/PSRAM) will be cache
+            missed after waking up, resulting in performance degradation due to increased memory accesses latency.
 
     config PM_POWER_DOWN_PERIPHERAL_IN_LIGHT_SLEEP
         bool "Power down Digital Peripheral in light sleep (EXPERIMENTAL)"

components/esp_pm/linker.lf

@@ -97,5 +97,5 @@ entries:
     if SOC_PM_CPU_RETENTION_BY_RTCCNTL = y:
         if PM_SLP_IRAM_OPT = y && PM_POWER_DOWN_CPU_IN_LIGHT_SLEEP = y:
             rtc_cntl_hal:rtc_cntl_hal_enable_cpu_retention (noflash)
-        if PM_SLP_IRAM_OPT = y && PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP = y:
+        if PM_SLP_IRAM_OPT = y && PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP = y:
             rtc_cntl_hal:rtc_cntl_hal_enable_tagmem_retention (noflash)

components/esp_pm/sdkconfig.rename

@@ -1,3 +1,4 @@
 # sdkconfig replacement configurations for deprecated options formatted as
 # CONFIG_DEPRECATED_OPTION CONFIG_NEW_OPTION
 CONFIG_ESP_SYSTEM_PM_POWER_DOWN_CPU                                      CONFIG_PM_POWER_DOWN_CPU_IN_LIGHT_SLEEP
+CONFIG_PM_POWER_DOWN_TAGMEM_IN_LIGHT_SLEEP                               CONFIG_PM_RESTORE_CACHE_TAGMEM_AFTER_LIGHT_SLEEP