boot_serial: espressif: ESP32-S2 serial recovery mode interface

Add the serial adapter for ESP32-S2 for boot recovery and MCUMGR
communication.

Signed-off-by: Almir Okato <almir.okato@espressif.com>
diff --git a/boot/espressif/hal/include/esp32s2/esp32s2.cmake b/boot/espressif/hal/include/esp32s2/esp32s2.cmake
index 588ec1c..7afafc6 100644
--- a/boot/espressif/hal/include/esp32s2/esp32s2.cmake
+++ b/boot/espressif/hal/include/esp32s2/esp32s2.cmake
@@ -5,6 +5,7 @@
 list(APPEND hal_srcs
     ${esp_idf_dir}/components/esp_hw_support/port/${MCUBOOT_TARGET}/regi2c_ctrl.c
     ${esp_idf_dir}/components/efuse/src/esp_efuse_api_key_esp32xx.c
+    ${esp_idf_dir}/components/esp_rom/patches/esp_rom_crc.c
     )
 
 list(APPEND LINKER_SCRIPTS
diff --git a/boot/espressif/hal/src/esp32s2/bootloader_init.c b/boot/espressif/hal/src/esp32s2/bootloader_init.c
index 90e329e..a3e4b2f 100644
--- a/boot/espressif/hal/src/esp32s2/bootloader_init.c
+++ b/boot/espressif/hal/src/esp32s2/bootloader_init.c
@@ -14,6 +14,8 @@
 #include "esp_rom_gpio.h"
 
 #include "bootloader_init.h"
+#include "bootloader_common.h"
+#include "bootloader_console.h"
 #include "bootloader_mem.h"
 #include "bootloader_clock.h"
 #include "bootloader_flash_config.h"
@@ -120,18 +122,6 @@
     return ESP_OK;
 }
 
-static void bootloader_init_uart_console(void)
-{
-    const int uart_num = 0;
-
-    uartAttach(NULL);
-    ets_install_uart_printf();
-    uart_tx_wait_idle(0);
-
-    const int uart_baud = CONFIG_ESP_CONSOLE_UART_BAUDRATE;
-    uart_div_modify(uart_num, (rtc_clk_apb_freq_get() << 4) / uart_baud);
-}
-
 static void bootloader_super_wdt_auto_feed(void)
 {
     REG_SET_BIT(RTC_CNTL_SWD_CONF_REG, RTC_CNTL_SWD_AUTO_FEED_EN);
@@ -158,7 +148,7 @@
     /* config clock */
     bootloader_clock_configure();
     /* initialize uart console, from now on, we can use ets_printf */
-    bootloader_init_uart_console();
+    bootloader_console_init();
     /* read bootloader header */
     if ((ret = bootloader_read_bootloader_header()) != ESP_OK) {
         goto err;
diff --git a/boot/espressif/port/esp32s2/bootloader.conf b/boot/espressif/port/esp32s2/bootloader.conf
index febafcc..de969f4 100644
--- a/boot/espressif/port/esp32s2/bootloader.conf
+++ b/boot/espressif/port/esp32s2/bootloader.conf
@@ -12,6 +12,37 @@
 CONFIG_ESP_SCRATCH_OFFSET=0x210000
 CONFIG_ESP_SCRATCH_SIZE=0x40000
 
+# Enables the MCUboot Serial Recovery, that allows the use of
+# MCUMGR to upload a firmware through the serial port
+# CONFIG_ESP_MCUBOOT_SERIAL=y
+# Use sector erasing (recommended) instead of entire image size
+# erasing when uploading through Serial Recovery
+# CONFIG_ESP_MCUBOOT_ERASE_PROGRESSIVELY=y
+
+# GPIO used to boot on Serial Recovery
+# CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT=5
+# GPIO input type (0 for Pull-down, 1 for Pull-up)
+# CONFIG_ESP_SERIAL_BOOT_GPIO_INPUT_TYPE=0
+# GPIO signal value
+# CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT_VAL=1
+# Delay time for identify the GPIO signal
+# CONFIG_ESP_SERIAL_BOOT_DETECT_DELAY_S=5
+# UART port used for serial communication (not needed when using USB)
+# CONFIG_ESP_SERIAL_BOOT_UART_NUM=1
+# GPIO for Serial RX signal
+# CONFIG_ESP_SERIAL_BOOT_GPIO_RX=18
+# GPIO for Serial TX signal
+# CONFIG_ESP_SERIAL_BOOT_GPIO_TX=17
+
+# Use UART0 for console printing (use either UART or USB alone)
+CONFIG_ESP_CONSOLE_UART=y
+CONFIG_ESP_CONSOLE_UART_NUM=0
+# Configures alternative UART port for console printing
+# (UART_NUM=0 must not be changed)
+# CONFIG_ESP_CONSOLE_UART_CUSTOM=y
+# CONFIG_ESP_CONSOLE_UART_TX_GPIO=17
+# CONFIG_ESP_CONSOLE_UART_RX_GPIO=18
+
 # CONFIG_ESP_SIGN_EC256=y
 # CONFIG_ESP_SIGN_ED25519=n
 # CONFIG_ESP_SIGN_RSA=n
diff --git a/boot/espressif/port/esp32s2/ld/bootloader.ld b/boot/espressif/port/esp32s2/ld/bootloader.ld
index 6db36e3..75315e1 100644
--- a/boot/espressif/port/esp32s2/ld/bootloader.ld
+++ b/boot/espressif/port/esp32s2/ld/bootloader.ld
@@ -40,6 +40,7 @@
     *libhal.a:bootloader_efuse_esp32s2.*(.literal .text .literal.* .text.*)
     *libhal.a:bootloader_utility.*(.literal .text .literal.* .text.*)
     *libhal.a:bootloader_sha.*(.literal .text .literal.* .text.*)
+    *libhal.a:bootloader_console.*(.literal .text .literal.* .text.*)
     *libhal.a:bootloader_console_loader.*(.literal .text .literal.* .text.*)
     *libhal.a:bootloader_panic.*(.literal .text .literal.* .text.*)
     *libhal.a:bootloader_soc.*(.literal .text .literal.* .text.*)
diff --git a/boot/espressif/port/esp32s2/serial_adapter.c b/boot/espressif/port/esp32s2/serial_adapter.c
new file mode 100644
index 0000000..0706a0d
--- /dev/null
+++ b/boot/espressif/port/esp32s2/serial_adapter.c
@@ -0,0 +1,191 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <bootutil/bootutil_log.h>
+
+#include <esp_rom_uart.h>
+#include <esp_rom_gpio.h>
+#include <esp_rom_sys.h>
+#include <esp_rom_caps.h>
+#include <soc/uart_periph.h>
+#include <soc/gpio_struct.h>
+#include <soc/io_mux_reg.h>
+#include <soc/rtc.h>
+#include <hal/gpio_types.h>
+#include <hal/gpio_ll.h>
+#include <hal/uart_ll.h>
+#include <hal/clk_gate_ll.h>
+#include <hal/gpio_hal.h>
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT
+#define SERIAL_BOOT_GPIO_DETECT     CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT
+#else
+#define SERIAL_BOOT_GPIO_DETECT     GPIO_NUM_5
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT_VAL
+#define SERIAL_BOOT_GPIO_DETECT_VAL     CONFIG_ESP_SERIAL_BOOT_GPIO_DETECT_VAL
+#else
+#define SERIAL_BOOT_GPIO_DETECT_VAL     1
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_DETECT_DELAY_S
+#define SERIAL_BOOT_DETECT_DELAY_S     CONFIG_ESP_SERIAL_BOOT_DETECT_DELAY_S
+#else
+#define SERIAL_BOOT_DETECT_DELAY_S     5
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_GPIO_INPUT_TYPE
+#define SERIAL_BOOT_GPIO_INPUT_TYPE    CONFIG_ESP_SERIAL_BOOT_GPIO_INPUT_TYPE
+#else
+// pull-down
+#define SERIAL_BOOT_GPIO_INPUT_TYPE    0
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_UART_NUM
+#define SERIAL_BOOT_UART_NUM    CONFIG_ESP_SERIAL_BOOT_UART_NUM
+#else
+#define SERIAL_BOOT_UART_NUM    ESP_ROM_UART_1
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_GPIO_RX
+#define SERIAL_BOOT_GPIO_RX     CONFIG_ESP_SERIAL_BOOT_GPIO_RX
+#else
+#define SERIAL_BOOT_GPIO_RX     GPIO_NUM_18
+#endif
+
+#ifdef CONFIG_ESP_SERIAL_BOOT_GPIO_TX
+#define SERIAL_BOOT_GPIO_TX     CONFIG_ESP_SERIAL_BOOT_GPIO_TX
+#else
+#define SERIAL_BOOT_GPIO_TX     GPIO_NUM_17
+#endif
+
+static uart_dev_t *serial_boot_uart_dev = (SERIAL_BOOT_UART_NUM == 0) ?
+                                          &UART0 :
+                                          &UART1;
+
+void console_write(const char *str, int cnt)
+{
+    uint32_t tx_len;
+    uint32_t write_len;
+
+    do {
+        tx_len = uart_ll_get_txfifo_len(serial_boot_uart_dev);
+        if (tx_len > 0) {
+            write_len = tx_len < cnt ? tx_len : cnt;
+            uart_ll_write_txfifo(serial_boot_uart_dev, (const uint8_t *)str, write_len);
+            cnt -= write_len;
+        }
+        MCUBOOT_WATCHDOG_FEED();
+        esp_rom_delay_us(1000);
+    } while (cnt > 0);
+}
+
+int console_read(char *str, int cnt, int *newline)
+{
+    uint32_t len = 0;
+    uint32_t read_len = 0;
+    bool stop = false;
+
+    do {
+        len = uart_ll_get_rxfifo_len(serial_boot_uart_dev);
+
+        if (len > 0) {
+            for (uint32_t i = 0; i < len; i++) {
+                /* Read the character from the RX FIFO */
+                uart_ll_read_rxfifo(serial_boot_uart_dev, (uint8_t *)&str[read_len], 1);
+                read_len++;
+                if (read_len == cnt - 1|| str[read_len - 1] == '\n') {
+                    stop = true;
+                    break;
+                }
+            }
+        }
+        MCUBOOT_WATCHDOG_FEED();
+        esp_rom_delay_us(1000);
+    } while (!stop);
+    *newline = (str[read_len - 1] == '\n') ? 1 : 0;
+    return read_len;
+}
+
+int boot_console_init(void)
+{
+    BOOT_LOG_INF("Initializing serial boot pins");
+
+    /* Enable GPIO for UART RX */
+    esp_rom_gpio_pad_select_gpio(SERIAL_BOOT_GPIO_RX);
+    esp_rom_gpio_connect_in_signal(SERIAL_BOOT_GPIO_RX,
+                                   UART_PERIPH_SIGNAL(SERIAL_BOOT_UART_NUM, SOC_UART_RX_PIN_IDX),
+                                   0);
+    gpio_ll_input_enable(&GPIO, SERIAL_BOOT_GPIO_RX);
+    esp_rom_gpio_pad_pullup_only(SERIAL_BOOT_GPIO_RX);
+
+    /* Enable GPIO for UART TX */
+    esp_rom_gpio_pad_select_gpio(SERIAL_BOOT_GPIO_TX);
+    esp_rom_gpio_connect_out_signal(SERIAL_BOOT_GPIO_TX,
+                                    UART_PERIPH_SIGNAL(SERIAL_BOOT_UART_NUM, SOC_UART_TX_PIN_IDX),
+                                    0, 0);
+    gpio_ll_output_enable(&GPIO, SERIAL_BOOT_GPIO_TX);
+
+    uart_ll_set_sclk(serial_boot_uart_dev, UART_SCLK_APB);
+    uart_ll_set_mode_normal(serial_boot_uart_dev);
+    uart_ll_set_baudrate(serial_boot_uart_dev, 115200);
+    uart_ll_set_stop_bits(serial_boot_uart_dev, 1u);
+    uart_ll_set_parity(serial_boot_uart_dev, UART_PARITY_DISABLE);
+    uart_ll_set_rx_tout(serial_boot_uart_dev, 16);
+    uart_ll_set_data_bit_num(serial_boot_uart_dev, UART_DATA_8_BITS);
+    uart_ll_set_tx_idle_num(serial_boot_uart_dev, 0);
+    uart_ll_set_hw_flow_ctrl(serial_boot_uart_dev, UART_HW_FLOWCTRL_DISABLE, 100);
+    periph_ll_enable_clk_clear_rst(PERIPH_UART0_MODULE + SERIAL_BOOT_UART_NUM);
+
+    uart_ll_txfifo_rst(serial_boot_uart_dev);
+    uart_ll_rxfifo_rst(serial_boot_uart_dev);
+    esp_rom_delay_us(50000);
+
+    return 0;
+}
+
+bool boot_serial_detect_pin(void)
+{
+    bool detected = false;
+    int pin_value = 0;
+
+    esp_rom_gpio_pad_select_gpio(SERIAL_BOOT_GPIO_DETECT);
+    gpio_ll_input_enable(&GPIO, SERIAL_BOOT_GPIO_DETECT);
+    switch (SERIAL_BOOT_GPIO_INPUT_TYPE) {
+        // Pull-down
+        case 0:
+            gpio_ll_pulldown_en(&GPIO, SERIAL_BOOT_GPIO_DETECT);
+            break;
+        // Pull-up
+        case 1:
+            gpio_ll_pullup_en(&GPIO, SERIAL_BOOT_GPIO_DETECT);
+            break;
+    }
+    esp_rom_delay_us(50000);
+
+    pin_value = gpio_ll_get_level(&GPIO, SERIAL_BOOT_GPIO_DETECT);
+    detected = (pin_value == SERIAL_BOOT_GPIO_DETECT_VAL);
+    esp_rom_delay_us(50000);
+
+    if (detected) {
+        if (SERIAL_BOOT_DETECT_DELAY_S > 0) {
+            /* The delay time is an approximation */
+            for (int i = 0; i < (SERIAL_BOOT_DETECT_DELAY_S * 100); i++) {
+                esp_rom_delay_us(10000);
+                pin_value = gpio_ll_get_level(&GPIO, SERIAL_BOOT_GPIO_DETECT);
+                detected = (pin_value == SERIAL_BOOT_GPIO_DETECT_VAL);
+                if (!detected) {
+                    break;
+                }
+            }
+        }
+    }
+    return detected;
+}