perf(usbh_serial): optimize memory usage and add shell cmd switch

Includes:
1. Add `CONFIG_USBHOST_SERIAL_CMD` in Kconfig to allow disable/enable the `usbh_serial` command.
2. Wrap the `usbh_serial` command and `g_serial_testbuffer` with the macro to save resources when not needed.

Result:
- Flash: Reduced by ~0.9KB (text) + potential stdlib removal (snprintf/atoi).
- RAM: Reduced by 512 Bytes (NoCache Data).

Author: MDLZCOOL

Kconfig

@@ -436,6 +436,12 @@ if CHERRYUSB
             prompt "Set host serial rx max buffer size"
             default 2048
 
+        config USBHOST_SERIAL_CMD
+            bool
+            prompt "Enable usbh_serial command for shell"
+            default n
+            depends on USBHOST_SERIAL
+
         menu "Select USB host template, please select class driver first"
             config TEST_USBH_SERIAL
                 bool

Kconfig.rtt

@@ -453,6 +453,12 @@ if RT_USING_CHERRYUSB
             prompt "Set host serial rx max buffer size"
             default 2048
 
+        config CONFIG_USBHOST_SERIAL_CMD
+            bool
+            prompt "Enable usbh_serial command for shell"
+            default n
+            depends on CONFIG_USBHOST_SERIAL
+
         config RT_LWIP_PBUF_POOL_BUFSIZE
             int "The size of each pbuf in the pbuf pool"
             range 1500 2000

Kconfig.rttpkg

@@ -452,6 +452,12 @@ if PKG_USING_CHERRYUSB
             prompt "Set host serial rx max buffer size"
             default 2048
 
+        config CONFIG_USBHOST_SERIAL_CMD
+            bool
+            prompt "Enable usbh_serial command for shell"
+            default n
+            depends on CONFIG_USBHOST_SERIAL
+
         config RT_LWIP_PBUF_POOL_BUFSIZE
             int "The size of each pbuf in the pbuf pool"
             range 1500 2000

class/serial/usbh_serial.c

@@ -618,6 +618,7 @@ int usbh_serial_cdc_read_async(struct usbh_serial *serial, uint8_t *buffer, uint
     return usbh_submit_urb(urb);
 }
 
+#ifdef CONFIG_USBHOST_SERIAL_CMD
 void usbh_serial_help(void)
 {
     USB_LOG_RAW("USB host serial test\r\n"
@@ -702,6 +703,7 @@ int usbh_serial(int argc, char **argv)
 
     return 0;
 }
+#endif
 
 __WEAK void usbh_serial_run(struct usbh_serial *serial)
 {

class/serial/usbh_serial.h

@@ -173,7 +173,9 @@ int usbh_serial_cdc_read_async(struct usbh_serial *serial, uint8_t *buffer, uint
 void usbh_serial_run(struct usbh_serial *serial);
 void usbh_serial_stop(struct usbh_serial *serial);
 
+#ifdef CONFIG_USBHOST_SERIAL_CMD
 int usbh_serial(int argc, char **argv);
+#endif
 
 #ifdef __cplusplus
 }

platform/rtthread/usb_msh.c

@@ -45,7 +45,7 @@ MSH_CMD_EXPORT(usbh_init, init usb host);
 MSH_CMD_EXPORT(usbh_deinit, deinit usb host);
 MSH_CMD_EXPORT(lsusb, ls usb devices);
 
-#ifdef CONFIG_USBHOST_SERIAL
+#if defined(CONFIG_USBHOST_SERIAL) && defined(CONFIG_USBHOST_SERIAL_CMD)
 #include "usbh_serial.h"
 MSH_CMD_EXPORT(usbh_serial, usbh_serial test);
 #endif

tests/hpmicro/inc/usb_config.h

@@ -268,6 +268,11 @@
 #define CONFIG_USBHOST_BLUETOOTH_RX_SIZE 2048
 #endif
 
+/* For CI/CD tests */
+#ifndef CONFIG_USBHOST_SERIAL_CMD
+#define CONFIG_USBHOST_SERIAL_CMD 1
+#endif
+
 /* ================ USB Device Port Configuration ================*/
 
 #define CONFIG_USBDEV_MAX_BUS USB_SOC_MAX_COUNT