esp_rom: implement usb deinit functions added in S3 ROM for S2

This cleans up usb_console.c and prepares it for S3 support.

components/esp_rom/esp32s2/usb_patches.c

@@ -0,0 +1,83 @@
+/*
+ * SPDX-FileCopyrightText: 2020-2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <string.h>
+#include "esp32s2/rom/usb/usb_common.h"
+#include "soc/soc.h"
+#include "hal/efuse_hal.h"
+
+/* USB CDC descriptor.
+ * Note that we aren't using the one in ROM since it doesn't
+ * set "serial" to the MAC address.
+ * However overriding the descriptor is cheap - we can reuse most
+ * of its components from ROM.
+ */
+
+/* This is not const, since the MAC address is only known at run time */
+static struct string_descriptor s_str_serial_descr = {
+    .bLength = 2 + 2 * 17,
+    .bDescriptorType = 0x03,
+    .bString={'0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0'}
+};
+
+static const struct rom_usb_descriptors s_acm_usb_descriptors_override = {
+    .device_descr = &general_device_descr,
+    .config_descr = { &acm_config_descr },
+    .string_count = 4,
+    .string0_descr = &string0_descr,
+    .string_descrs = {
+        &str_manu_descr,
+        &str_prod_descr,
+        &s_str_serial_descr
+    }
+};
+
+static inline uint16_t nibble_to_hex_u16(uint8_t b)
+{
+    if (b < 0xa) {
+        return '0' + b;
+    } else {
+        return 'a' + b - 0xa;
+    }
+}
+
+void rom_usb_cdc_set_descriptor_patch(void)
+{
+    uint8_t mac_bytes[6];
+    efuse_hal_get_mac(mac_bytes);
+    /* Convert to UTF16 string */
+#pragma GCC diagnostic push
+#if     __GNUC__ >= 9
+#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
+#endif
+    uint16_t* dst = s_str_serial_descr.bString;
+    for (int i = 0; i < 6; ++i) {
+        uint8_t b = mac_bytes[5 - i]; /* printing from the MSB */
+        *dst++ = nibble_to_hex_u16(b >> 4);
+        *dst++ = nibble_to_hex_u16(b & 0xf);
+        dst++;
+    }
+#pragma GCC diagnostic pop
+
+    /* Override the pointer to descriptors structure */
+    rom_usb_curr_desc = &s_acm_usb_descriptors_override;
+}
+
+/* On ESP32-S2, ROM doesn't provide interfaces to clear usb_dev and usb_dw_ctrl structures.
+ * Starting from ESP32-S3, usb_dev_deinit and usb_dw_ctrl_deinit ROM functions are available.
+ * Here we implement the missing functionality for the ESP32-S2.
+ */
+void usb_dev_deinit(void)
+{
+    extern char rom_usb_dev, rom_usb_dev_end;
+    memset((void *) &rom_usb_dev, 0, &rom_usb_dev_end - &rom_usb_dev);
+}
+
+void usb_dw_ctrl_deinit(void)
+{
+    extern char rom_usb_dw_ctrl, rom_usb_dw_ctrl_end;
+    memset((void *) &rom_usb_dw_ctrl, 0, &rom_usb_dw_ctrl_end - &rom_usb_dw_ctrl);
+}