Add memory diagnostics and optimize PSRAM usage

src/system_console.c

@@ -3,13 +3,42 @@
 
 #include "system_console.h"
 
+#include <stdint.h>
 #include <stdio.h>
 
 #include "esp_console.h"
+#include "esp_heap_caps.h"
 #include "esp_system.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 
+static void print_heap_region(const char *name, uint32_t capabilities)
+{
+    printf("%s: free=%u minimum-free=%u largest-block=%u bytes\n",
+           name,
+           (unsigned int)heap_caps_get_free_size(capabilities),
+           (unsigned int)heap_caps_get_minimum_free_size(capabilities),
+           (unsigned int)heap_caps_get_largest_free_block(capabilities));
+}
+
+static int command_memory(int argc, char **argv)
+{
+    (void)argv;
+    if (argc != 1) {
+        printf("Usage: memory\n");
+        return 1;
+    }
+
+    print_heap_region("Internal 8-bit heap",
+                      MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
+    print_heap_region("Internal DMA heap",
+                      MALLOC_CAP_INTERNAL | MALLOC_CAP_DMA | MALLOC_CAP_8BIT);
+    print_heap_region("External PSRAM",
+                      MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
+    printf("Minimum-free is a conservative sum of each matching heap region's lifetime minimum.\n");
+    return 0;
+}
+
 static int command_reboot(int argc, char **argv)
 {
     (void)argv;
@@ -28,12 +57,24 @@ static int command_reboot(int argc, char **argv)
 
 esp_err_t system_console_register_commands(void)
 {
-    const esp_console_cmd_t command = {
+    const esp_console_cmd_t reboot_command = {
         .command = "reboot",
         .help = "Restart the ESP32; unsaved RAM-only configuration is lost",
         .hint = NULL,
         .func = &command_reboot,
         .argtable = NULL,
     };
-    return esp_console_cmd_register(&command);
+    esp_err_t error = esp_console_cmd_register(&reboot_command);
+    if (error != ESP_OK) {
+        return error;
+    }
+
+    const esp_console_cmd_t memory_command = {
+        .command = "memory",
+        .help = "Show internal and PSRAM heap availability/low-water marks",
+        .hint = NULL,
+        .func = &command_memory,
+        .argtable = NULL,
+    };
+    return esp_console_cmd_register(&memory_command);
 }