risc-v/esp32-c3: complements serial driver

arch/risc-v/src/esp32c3/Kconfig

@@ -225,4 +225,33 @@ config ESP32C3_RWDT
 
 endmenu
 
+menu "UART configuration"
+	depends on ESP32C3_UART
+
+if ESP32C3_UART0
+
+config ESP32C3_UART0_TXPIN
+	int "UART0 TX Pin"
+	default 21
+
+config ESP32C3_UART0_RXPIN
+	int "UART0 RX Pin"
+	default 20
+
+endif # ESP32C3_UART0
+
+if ESP32C3_UART1
+
+config ESP32C3_UART1_TXPIN
+	int "UART1 TX Pin"
+	default 18
+
+config ESP32C3_UART1_RXPIN
+	int "UART1 RX Pin"
+	default 19
+
+endif # ESP32C3_UART1
+
+endmenu
+
 endif # ARCH_CHIP_ESP32C3

arch/risc-v/src/esp32c3/esp32c3_gpio.h

@@ -34,6 +34,10 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+#define MATRIX_DETACH_OUT_SIG     0x100  /* Detach an OUTPUT signal */
+#define MATRIX_DETACH_IN_LOW_PIN  0x30   /* Detach non-inverted INPUT signal */
+#define MATRIX_DETACH_IN_LOW_HIGH 0x38   /* Detach inverted INPUT signal */
+
 /* Bit-encoded input to esp32c3_configgpio() ********************************/
 
 /* Encoded pin attributes used with esp32c3_configgpio()
@@ -149,8 +153,8 @@ bool esp32c3_gpioread(int pin);
  * Description:
  *   Set gpio input to a signal
  *   NOTE: one gpio can input to several signals
- *   If gpio == 0x30, cancel input to the signal, input 0 to signal
+ *   If signal_idx == 0x30, cancel input to the signal, input 0 to signal
- *   If gpio == 0x38, cancel input to the signal, input 1 to signal
+ *   If signal_idx == 0x38, cancel input to the signal, input 1 to signal
  *
  ****************************************************************************/
 

arch/risc-v/src/esp32c3/esp32c3_lowputc.h

@@ -37,9 +37,13 @@
 #include <errno.h>
 #include <debug.h>
 
-#include "hardware/esp32c3_uart.h"
 #include "chip.h"
 
+#include "hardware/esp32c3_uart.h"
+#include "hardware/esp32c3_gpio_sigmap.h"
+
+#include "esp32c3_irq.h"
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -68,8 +72,8 @@ enum uart_data_length
 
 enum uart_stop_length
 {
-    UART_STOP_BITS_1   = 0x1,  /* stop bit: 1 bit */
+    UART_STOP_BITS_1   = 0x1,  /* Stop bit: 1 bit */
-    UART_STOP_BITS_2   = 0x3,  /* stop bit: 2bits */
+    UART_STOP_BITS_2   = 0x3,  /* Stop bit: 2 bits */
 };
 
 /* Default FIFOs size */
@@ -83,7 +87,6 @@ enum uart_stop_length
 
 struct esp32c3_uart_s
 {
-  uint32_t  base;           /* Base address of UART registers */
   uint8_t   periph;         /* UART peripheral ID */
   int       cpuint;         /* CPU interrupt assigned to this UART */
   uint8_t   id;             /* UART ID */
@@ -93,6 +96,10 @@ struct esp32c3_uart_s
   uint8_t   parity;         /* 0=no parity, 1=odd parity, 2=even parity */
   uint8_t   stop_b2;        /* Use 2 stop bits? 0 no, others yes */
   uint8_t   int_pri;        /* UART Interrupt Priority */
+  uint8_t   txpin;          /* TX pin */
+  uint8_t   txsig;          /* TX signal */
+  uint8_t   rxpin;          /* RX pin */
+  uint8_t   rxsig;          /* RX signal */
 };
 
 /****************************************************************************
@@ -101,101 +108,316 @@ struct esp32c3_uart_s
 
 /****************************************************************************
  * Name: esp32c3_lowputc_reset_core
- *  Reset both TX and RX core
+ *
+ * Description:
+ *   Reset both TX and RX cores.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_reset_core(const struct esp32c3_uart_s *conf);
+void esp32c3_lowputc_reset_cores(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_rst_tx
+ *
+ * Description:
+ *   Reset TX core.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_rst_tx(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_rst_rx
+ *
+ * Description:
+ *   Reset RX core.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_rst_rx(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_enable_sclk
- *    Enable clock for whole core
+ *
+ * Description:
+ *   Enable clock for whole core.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_enable_sclk(const struct esp32c3_uart_s *conf);
+void esp32c3_lowputc_enable_sclk(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_disable_sclk
- *    Disable clock for whole core
+ *
+ * Description:
+ *   Disable clock for whole core.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_disable_sclk(const struct esp32c3_uart_s *conf);
+void esp32c3_lowputc_disable_sclk(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_set_sclk
- *    Set a source clock for UART
+ *
- *    APB_CLK  = 1  80 MHz
+ * Description:
- *    CLK_8    = 2        8 MHz
+ *   Set a source clock for UART.
- *    XTAL_CLK = 3
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *   source         - APB_CLK  = 1  80 MHz
+ *                    CLK_8    = 2  8 MHz
+ *                    XTAL_CLK = 3
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_set_sclk(const struct esp32c3_uart_s *conf, enum
+void esp32c3_lowputc_set_sclk(const struct esp32c3_uart_s *priv,
-                              uart_sclk source);
+                              enum uart_sclk source);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_get_sclk
- *    Get the source clock for UART
+ *
+ * Description:
+ *   Get the source clock for UART.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ * Returned Value:
+ *   The frequency of the clock in Hz.
+ *
  ****************************************************************************/
 
-uint32_t esp32c3_lowputc_get_sclk(const struct esp32c3_uart_s *conf);
+uint32_t esp32c3_lowputc_get_sclk(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_baud
- *    Set the baud rate
+ *
+ * Description:
+ *   Set the baud rate according to the value in the private driver
+ *   struct.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_baud(const struct esp32c3_uart_s * conf);
+void esp32c3_lowputc_baud(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_normal_mode
- *    Set the UART to operate in normal mode
+ *
+ * Description:
+ *   Set the UART to operate in normal mode, i.e., disable the RS485 mode and
+ *   IRDA mode.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_normal_mode(const struct esp32c3_uart_s * conf);
+void esp32c3_lowputc_normal_mode(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_parity
- *    Set the parity
+ *
+ * Description:
+ *   Set the parity, according to the value in the private driver
+ *   struct.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_parity(const struct esp32c3_uart_s * conf);
+void esp32c3_lowputc_parity(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_data_length
- *    Set the data length
+ *
+ * Description:
+ *   Set the data bits length, according to the value in the private driver
+ *   struct.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-int esp32c3_lowputc_data_length(const struct esp32c3_uart_s * conf);
+int esp32c3_lowputc_data_length(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_stop_length
- *    Set the stop length
+ *
+ * Description:
+ *   Set the stop bits length, according to the value in the private driver
+ *   struct.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_stop_length(const struct esp32c3_uart_s * conf);
+void esp32c3_lowputc_stop_length(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_set_tx_idle_time
- *    Set the idle time between transfers
+ *
+ * Description:
+ *   Set the idle time between transfers.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *   time           - Desired time interval between the transfers.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_set_tx_idle_time(const struct esp32c3_uart_s *
+void esp32c3_lowputc_set_tx_idle_time(const struct esp32c3_uart_s *priv,
-                                      conf, uint32_t time);
+                                      uint32_t time);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_send_byte
- *    Send one byte
+ *
+ * Description:
+ *   Send one byte.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *   byte           - Byte to be sent.
+ *
  ****************************************************************************/
 
-void esp32c3_lowputc_send_byte(const struct esp32c3_uart_s * conf,
+void esp32c3_lowputc_send_byte(const struct esp32c3_uart_s *priv,
                                char byte);
 
 /****************************************************************************
  * Name: esp32c3_lowputc_is_tx_fifo_full
- *    Send one byte
+ *
+ * Description:
+ *   Verify if TX FIFO is full.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ * Returned Value:
+ *   True if it is full, otherwise false.
+ *
  ****************************************************************************/
 
-bool esp32c3_lowputc_is_tx_fifo_full(const struct esp32c3_uart_s *
+bool esp32c3_lowputc_is_tx_fifo_full(const struct esp32c3_uart_s *priv);
-                                     conf);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_rst_peripheral
+ *
+ * Description:
+ *   Reset the UART peripheral by using System reg.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_rst_peripheral(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_rst_txfifo
+ *
+ * Description:
+ *   Reset TX FIFO.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_rst_txfifo(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_rst_rxfifo
+ *
+ * Description:
+ *   Reset RX FIFO.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_rst_rxfifo(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_disable_all_uart_int
+ *
+ * Description:
+ *   Disable all UART interrupts.
+ *
+ * Parameters:
+ *   priv           - Pointer to the private driver struct.
+ *   current_status - Pointer to a variable to store the current status of
+ *                    the interrupt enable register before disabling
+ *                    UART interrupts.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_disable_all_uart_int(const struct esp32c3_uart_s *priv,
+                                          uint32_t *current_status);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_restore_all_uart_int
+ *
+ * Description:
+ *   Restore all UART interrupts.
+ *
+ * Parameters:
+ *   priv        - Pointer to the private driver struct.
+ *   last_status - Pointer to a variable that stored the last state of the
+ *                 interrupt enable register.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_restore_all_uart_int(const struct esp32c3_uart_s *priv,
+                                          uint32_t * last_status);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_config_pins
+ *
+ * Description:
+ *   Configure TX and RX UART pins.
+ *
+ * Parameters:
+ *   priv        - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_config_pins(const struct esp32c3_uart_s *priv);
+
+/****************************************************************************
+ * Name: esp32c3_lowputc_restore_pins
+ *
+ * Description:
+ *   Configure both pins back to INPUT mode and detach the TX pin from the
+ *   output signal and the RX pin from the input signal.
+ *
+ * Parameters:
+ *   priv        - Pointer to the private driver struct.
+ *
+ ****************************************************************************/
+
+void esp32c3_lowputc_restore_pins(const struct esp32c3_uart_s *priv);
 
 /****************************************************************************
  * Name: esp32c3_lowsetup

arch/risc-v/src/esp32c3/esp32c3_serial.c

@@ -35,13 +35,16 @@
 #include <errno.h>
 #include <debug.h>
 
-#include "hardware/esp32c3_uart.h"
 #include "riscv_internal.h"
 #include "riscv_arch.h"
 #include "chip.h"
-#include "esp32c3_lowputc.h"
+
+#include "hardware/esp32c3_uart.h"
+#include "hardware/esp32c3_system.h"
+
 #include "esp32c3_config.h"
 #include "esp32c3_irq.h"
+#include "esp32c3_lowputc.h"
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -149,15 +152,19 @@ static char g_uart0_txbuffer[CONFIG_UART0_TXBUFSIZE];
 
 static struct esp32c3_uart_s g_uart0_config =
 {
-  .base = REG_UART_BASE(0),
   .periph = ESP32C3_PERIPH_UART0,
   .id = 0,
+  .cpuint = -ENOMEM,
   .irq = ESP32C3_IRQ_UART0,
   .baud = CONFIG_UART0_BAUD,
   .bits = CONFIG_UART0_BITS,
   .parity = CONFIG_UART0_PARITY,
   .stop_b2 =  CONFIG_UART0_2STOP,
-  .int_pri = 1
+  .int_pri = ESP32C3_INT_PRIO_DEF,
+  .txpin = CONFIG_ESP32C3_UART0_TXPIN,
+  .txsig = U0TXD_OUT_IDX,
+  .rxpin = CONFIG_ESP32C3_UART0_RXPIN,
+  .rxsig = U0RXD_IN_IDX,
 };
 
 /* Fill only the requested fields */
@@ -195,15 +202,19 @@ static char g_uart1_txbuffer[CONFIG_UART1_TXBUFSIZE];
 
 static struct esp32c3_uart_s g_uart1_config =
 {
-  .base = REG_UART_BASE(1),
   .periph = ESP32C3_PERIPH_UART1,
   .id = 1,
+  .cpuint = -ENOMEM,
   .irq = ESP32C3_IRQ_UART1,
   .baud = CONFIG_UART1_BAUD,
   .bits = CONFIG_UART1_BITS,
   .parity = CONFIG_UART1_PARITY,
   .stop_b2 =  CONFIG_UART1_2STOP,
-  .int_pri = 1
+  .int_pri = ESP32C3_INT_PRIO_DEF,
+  .txpin = CONFIG_ESP32C3_UART1_TXPIN,
+  .txsig = U1TXD_OUT_IDX,
+  .rxpin = CONFIG_ESP32C3_UART1_RXPIN,
+  .rxsig = U1RXD_IN_IDX,
 };
 
 /* Fill only the requested fields */
@@ -241,8 +252,8 @@ static uart_dev_t g_uart1_dev =
  *
  * Description:
  *   This is the UART interrupt handler.  It will be invoked when an
- *   interrupt received on the 'irq'  It should call uart_transmitchars or
+ *   interrupt is received on the 'irq'  It should call uart_xmitchars or
- *   uart_receivechar to perform the appropriate data transfers.  The
+ *   uart_recvchars to perform the appropriate data transfers.  The
  *   interrupt handling logic must be able to map the 'irq' number into the
  *   appropriate uart_dev_s structure in order to call these functions.
  *
@@ -289,10 +300,52 @@ static int uart_handler(int irq, FAR void *context, FAR void *arg)
  *      That portion of the UART setup is performed when the attach() method
  *      is called.
  *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
+ * Returned Values:
+ *   Zero (OK) is returned.
+ *
  ****************************************************************************/
 
 static int esp32c3_setup(struct uart_dev_s *dev)
 {
+  struct esp32c3_uart_s *priv = dev->priv;
+
+  /* Initialize UART module */
+
+  /* Configure the UART Baud Rate */
+
+  esp32c3_lowputc_baud(priv);
+
+  /* Set a mode */
+
+  esp32c3_lowputc_normal_mode(priv);
+
+  /* Parity */
+
+  esp32c3_lowputc_parity(priv);
+
+  /* Data Frame size */
+
+  esp32c3_lowputc_data_length(priv);
+
+  /* Stop bit */
+
+  esp32c3_lowputc_stop_length(priv);
+
+  /* No Tx idle interval */
+
+  esp32c3_lowputc_set_tx_idle_time(priv, 0);
+
+  /* Set pins */
+
+  esp32c3_lowputc_config_pins(priv);
+
+  /* Enable cores */
+
+  esp32c3_lowputc_enable_sclk(priv);
+
   return OK;
 }
 
@@ -304,10 +357,27 @@ static int esp32c3_setup(struct uart_dev_s *dev)
  * This method reverses the operation the setup method.  NOTE that the serial
  * console is never shutdown.
  *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
  ****************************************************************************/
 
 static void esp32c3_shutdown(struct uart_dev_s *dev)
 {
+  struct esp32c3_uart_s *priv = dev->priv;
+
+  /* Clear FIFOs */
+
+  esp32c3_lowputc_rst_txfifo(priv);
+  esp32c3_lowputc_rst_rxfifo(priv);
+
+  /* Disable ints */
+
+  esp32c3_lowputc_disable_all_uart_int(priv, NULL);
+
+  /* Back pins to normal */
+
+  esp32c3_lowputc_restore_pins(priv);
 }
 
 /****************************************************************************
@@ -324,6 +394,13 @@ static void esp32c3_shutdown(struct uart_dev_s *dev)
  *   and TX interrupts are not enabled until the txint() and rxint() methods
  *   are called.
  *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
+ * Returned Values:
+ *   Zero (OK) is returned on success; A negated errno value is returned
+ *   to indicate the nature of any failure.
+ *
  ****************************************************************************/
 
 static int esp32c3_attach(struct uart_dev_s *dev)
@@ -331,6 +408,8 @@ static int esp32c3_attach(struct uart_dev_s *dev)
   struct esp32c3_uart_s *priv = dev->priv;
   int ret;
 
+  DEBUGASSERT(priv->cpuint == -ENOMEM);
+
   /* Try to attach the IRQ to a CPU int */
 
   priv->cpuint = esp32c3_request_irq(priv->periph, priv->int_pri,
@@ -347,6 +426,10 @@ static int esp32c3_attach(struct uart_dev_s *dev)
     {
       up_enable_irq(priv->cpuint);
     }
+  else
+    {
+      up_disable_irq(priv->cpuint);
+    }
 
   return ret;
 }
@@ -359,39 +442,45 @@ static int esp32c3_attach(struct uart_dev_s *dev)
  *   closed normally just before the shutdown method is called.  The
  *   exception is the serial console which is never shutdown.
  *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
  ****************************************************************************/
 
 static void esp32c3_detach(struct uart_dev_s *dev)
 {
   struct esp32c3_uart_s *priv = dev->priv;
 
+  DEBUGASSERT(priv->cpuint != -ENOMEM);
+
   up_disable_irq(priv->cpuint);
   irq_detach(priv->irq);
   esp32c3_free_cpuint(priv->periph);
+  priv->cpuint = -ENOMEM;
 }
 
 /****************************************************************************
  * Name: esp32c3_txint
  *
  * Description:
- * Call to enable or disable TX interrupts
+ *    Enable or disable TX interrupts.
+ *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *   enable     -  If true enables the TX interrupt, if false disables it.
  *
  ****************************************************************************/
 
 static void esp32c3_txint(struct uart_dev_s *dev, bool enable)
 {
   struct esp32c3_uart_s *priv = dev->priv;
-  irqstate_t flags;
   uint32_t ints_mask = UART_TXFIFO_EMPTY_INT_ENA_M | UART_TX_DONE_INT_ENA_M;
 
-  flags = enter_critical_section();
-
   if (enable)
     {
       /* Set to receive an interrupt when the TX holding register register
        * is empty
        */
-
 #ifndef CONFIG_SUPPRESS_SERIAL_INTS
       modifyreg32(UART_INT_ENA_REG(priv->id), ints_mask, ints_mask);
 #endif
@@ -402,52 +491,58 @@ static void esp32c3_txint(struct uart_dev_s *dev, bool enable)
 
       modifyreg32(UART_INT_ENA_REG(priv->id), ints_mask, 0);
     }
-
-  leave_critical_section(flags);
 }
 
 /****************************************************************************
  * Name: esp32c3_rxint
  *
  * Description:
- *   Call to enable or disable RXRDY interrupts
+ *   Enable or disable RX interrupts.
+ *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *   enable     -  If true enables the RX interrupt, if false disables it.
  *
  ****************************************************************************/
 
 static void esp32c3_rxint(struct uart_dev_s *dev, bool enable)
 {
   struct esp32c3_uart_s *priv = dev->priv;
-  irqstate_t flags;
   uint32_t ints_mask = UART_RXFIFO_TOUT_INT_ENA_M |
                        UART_RXFIFO_FULL_INT_ENA_M;
 
-  flags = enter_critical_section();
-
   if (enable)
     {
-      /* Receive an interrupt when their is anything in the Rx data register
+      /* Receive an interrupt when there is anything in the Rx data register
        * (or an Rx timeout occurs).
        */
-
 #ifndef CONFIG_SUPPRESS_SERIAL_INTS
+      modifyreg32(UART_CONF1_REG(priv->id), UART_RX_TOUT_EN_M,
+                  UART_RX_TOUT_EN_M);
       modifyreg32(UART_INT_ENA_REG(priv->id), ints_mask, ints_mask);
 #endif
     }
   else
     {
+      modifyreg32(UART_CONF1_REG(priv->id), UART_RX_TOUT_EN_M, 0);
+
       /* Disable the RX interrupts */
 
       modifyreg32(UART_INT_ENA_REG(priv->id), ints_mask, 0);
     }
-
-  leave_critical_section(flags);
 }
 
 /****************************************************************************
  * Name: esp32c3_rxavailable
  *
  * Description:
- *   Return true if the receive holding register is not empty
+ *   Check if there is any data available to be read.
+ *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
+ * Returned Values:
+ *   Return true if the RX FIFO is not empty and false if RX FIFO is empty.
  *
  ****************************************************************************/
 
@@ -467,8 +562,15 @@ static bool esp32c3_rxavailable(struct uart_dev_s *dev)
  * Name: esp32c3_txready
  *
  * Description:
- * Return true if the tranmsit hardware is ready to send another byte.  This
+ *    Check if the transmit hardware is ready to send another byte.
- * is used to determine if send() method can be called.
+ *    This is used to determine if send() method can be called.
+ *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
+ * Returned Values:
+ *   Return true if the transmit hardware is ready to send another byte,
+ *   false otherwise.
  *
  ****************************************************************************/
 
@@ -481,10 +583,16 @@ static bool esp32c3_txready(struct uart_dev_s *dev)
  * Name: esp32c3_txempty
  *
  * Description:
- * Return true if all characters have been sent.  If for example, the UART
+ *    Verify if all characters have been sent. If for example, the UART
- * hardware implements FIFOs, then this would mean the transmit FIFO is
+ *    hardware implements FIFOs, then this would mean the transmit FIFO is
- * empty.  This method is called when the driver needs to make sure that
+ *    empty. This method is called when the driver needs to make sure that
- * all characters are "drained" from the TX hardware.
+ *    all characters are "drained" from the TX hardware.
+ *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *
+ * Returned Values:
+ *   Return true if the TX FIFO is empty, false if it is not.
  *
  ****************************************************************************/
 
@@ -500,19 +608,19 @@ static bool esp32c3_txempty(struct uart_dev_s *dev)
 }
 
 /****************************************************************************
- * Name: esp32c3_shutdown
+ * Name: esp32c3_send
  *
  * Description:
- * Disable the UART.  This method is called when the serial port is closed.
+ *    Send a unique character
- * This method reverses the operation the setup method.  NOTE that the serial
+ *
- * console is never shutdown.
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *   ch         -  Byte to be sent.
  *
  ****************************************************************************/
 
 static void esp32c3_send(struct uart_dev_s *dev, int ch)
 {
-  /* Then send the character */
-
   esp32c3_lowputc_send_byte(dev->priv, ch);
 }
 
@@ -524,6 +632,13 @@ static void esp32c3_send(struct uart_dev_s *dev, int ch)
  *   character from the UART.  Error bits associated with the
  *   receipt are provided in the return 'status'.
  *
+ * Parameters:
+ *   dev        -  Pointer to the serial driver struct.
+ *   status     -  Pointer to a variable to store eventual error bits.
+ *
+ * Returned Values:
+ *   Return the byte read from the RX FIFO.
+ *
  ****************************************************************************/
 
 static int esp32c3_receive(struct uart_dev_s *dev, unsigned int *status)
@@ -534,6 +649,10 @@ static int esp32c3_receive(struct uart_dev_s *dev, unsigned int *status)
   rx_fifo = getreg32(UART_FIFO_REG(priv->id));
   rx_fifo = rx_fifo & UART_RXFIFO_RD_BYTE_M;
 
+  /* Since we don't have error bits associated with receipt, we set zero */
+
+  *status = 0;
+
   return (int)rx_fifo;
 }
 
@@ -582,8 +701,6 @@ void up_earlyserialinit(void)
  *
  ****************************************************************************/
 
-/* TODO */
-
 void up_serialinit(void)
 {
 #ifdef HAVE_SERIAL_CONSOLE
@@ -607,13 +724,12 @@ void up_serialinit(void)
  *
  ****************************************************************************/
 
-/* TODO - To finish later with interrupt */
-
 int up_putc(int ch)
 {
 #ifdef HAVE_SERIAL_CONSOLE
+  uint32_t int_status;
 
-  /* TODO disable uart ints */
+  esp32c3_lowputc_disable_all_uart_int(CONSOLE_DEV.priv, &int_status);
 
   /* Check for LF */
 
@@ -625,8 +741,7 @@ int up_putc(int ch)
     }
 
   up_lowputc(ch);
-
+  esp32c3_lowputc_restore_all_uart_int(CONSOLE_DEV.priv, &int_status);
-  /* TODO restore ints */
 #endif
   return ch;
 }
@@ -674,11 +789,13 @@ int up_putc(int ch)
  *
  ****************************************************************************/
 
-/* TODO - Finish it disabling interrupt and restoring it later */
-
 int up_putc(int ch)
 {
 #ifdef HAVE_SERIAL_CONSOLE
+  uint32_t int_status;
+
+  esp32c3_lowputc_disable_all_uart_int(CONSOLE_DEV.priv, &int_status);
+
   /* Check for LF */
 
   if (ch == '\n')
@@ -689,6 +806,7 @@ int up_putc(int ch)
     }
 
   up_lowputc(ch);
+  esp32c3_lowputc_restore_all_uart_int(CONSOLE_DEV.priv, &int_status);
 #endif
   return ch;
 }