feat(l2mem): enable buffer mode for ahb burst access

components/esp_system/port/cpu_start.c

@@ -58,6 +58,7 @@
 #include "esp32c2/rom/secure_boot.h"
 #elif CONFIG_IDF_TARGET_ESP32P4
 #include "soc/hp_sys_clkrst_reg.h"
+#include "hal/l2mem_ll.h"
 #elif CONFIG_IDF_TARGET_ESP32H21
 #include "esp_memprot.h"
 #endif
@@ -403,6 +404,11 @@ void IRAM_ATTR call_start_cpu0(void)
     );
 #endif
 
+#if CONFIG_IDF_TARGET_ESP32P4
+    // enable the buffer mode before any AHB burst happens, that's why we do it here
+    l2mem_ll_enable_ahb_burst_buffer(true, true);
+#endif
+
 #if SOC_BRANCH_PREDICTOR_SUPPORTED
     esp_cpu_branch_prediction_enable();
 #endif

components/hal/esp32p4/include/hal/l2mem_ll.h

@@ -0,0 +1,31 @@
+/*
+ * SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "soc/hp_system_struct.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Enable the burst buffer for L2 memory
+ *
+ * @note During AHB burst access to the L2MEM, in order to reduce the AHB request to the L2MEM arbiter,
+ *       enabling the buffer mode can improve the performance.
+ * @note This function must be called before any AHB burst access to the L2MEM.
+ */
+static inline void l2mem_ll_enable_ahb_burst_buffer(bool en_read, bool en_write)
+{
+    HP_SYSTEM.l2_mem_ahb_buffer_ctrl.l2_mem_ahb_rdbuffer_en = en_read;
+    HP_SYSTEM.l2_mem_ahb_buffer_ctrl.l2_mem_ahb_wrbuffer_en = en_write;
+}
+
+#ifdef __cplusplus
+}
+#endif