dif_gpio.h

// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0

#ifndef OPENTITAN_SW_DEVICE_LIB_DIF_DIF_GPIO_H_
#define OPENTITAN_SW_DEVICE_LIB_DIF_DIF_GPIO_H_

/**
 * @file
 * @brief <a href="/hw/ip/gpio/doc/">GPIO</a> Device Interface Functions
 */

#include <stddef.h>
#include <stdint.h>

#include "sw/device/lib/base/macros.h"
#include "sw/device/lib/base/mmio.h"
#include "sw/device/lib/dif/dif_base.h"

#include "sw/device/lib/dif/autogen/dif_gpio_autogen.h"

#ifdef __cplusplus
extern "C" {
#endif  // __cplusplus

enum {
  /**
   * Number of pins.
   *
   * This constant is used to check that arguments of type `dif_gpio_pin_t` are
   * within bounds.
   */
  kDifGpioNumPins = 32,
};

/**
 * A GPIO interrupt request trigger.
 *
 * Each GPIO pin has an associated interrupt that can be independently
 * configured to be edge and/or level sensitive. This enum defines supported
 * configurations for these interrupts.
 */
typedef enum dif_gpio_irq_trigger {
  /**
   * Trigger on rising edge.
   */
  kDifGpioIrqTriggerEdgeRising,
  /**
   * Trigger on falling edge.
   */
  kDifGpioIrqTriggerEdgeFalling,
  /**
   * Trigger when input is low.
   */
  kDifGpioIrqTriggerLevelLow,
  /**
   * Trigger when input is high.
   */
  kDifGpioIrqTriggerLevelHigh,
  /**
   * Trigger on rising and falling edges.
   */
  kDifGpioIrqTriggerEdgeRisingFalling,
  /**
   * Trigger on rising edge or when the input is low.
   */
  kDifGpioIrqTriggerEdgeRisingLevelLow,
  /**
   * Trigger on falling edge or when the input is high.
   */
  kDifGpioIrqTriggerEdgeFallingLevelHigh,
} dif_gpio_irq_trigger_t;

/**
 * A GPIO pin index, ranging from 0 to `kDifGpioNumPins - 1`.
 */
typedef uint32_t dif_gpio_pin_t;

/**
 * State for all 32 GPIO pins, given as bit fields.
 *
 * The Nth bit represents the state of the Nth pin.
 *
 * This type is also used as a vector of `dif_toggle_t`s, to indicate
 * toggle state across all 32 pins. A set bit corresponds to
 * `kDifGpioToggleEnabled`.
 */
typedef uint32_t dif_gpio_state_t;

/**
 * A mask for selecting GPIO pins.
 *
 * If the Nth bit is enabled, then the Nth pin is selected by the mask.
 */
typedef uint32_t dif_gpio_mask_t;

/**
 * Resets a GPIO device.
 *
 * Resets the given GPIO device by setting its configuration registers to
 * reset values. Disables interrupts, output, and input filter.
 *
 * @param gpio A GPIO handle.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_reset(const dif_gpio_t *gpio);

/**
 * Configures interrupt triggers for a set of pins.
 *
 * This function configures interrupt triggers, i.e. rising-edge, falling-edge,
 * level-high, and level-low, for the pins given by the mask. Note that
 * interrupt of the pin must also be enabled to generate interrupts.
 *
 * @param gpio A GPIO handle.
 * @param mask Mask that identifies the pins whose interrupt triggers will be
 * configured.
 * @param trigger New configuration of interrupt triggers.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_irq_set_trigger(const dif_gpio_t *gpio,
                                      dif_gpio_mask_t mask,
                                      dif_gpio_irq_trigger_t trigger);

/**
 * Reads from a pin.
 *
 * The value returned by this function is independent of the output enable
 * setting and includes the effects of the input noise filter and the load on
 * the pin.
 *
 * @param gpio A GPIO handle.
 * @param pin A GPIO pin.
 * @param[out] state Pin value.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_read(const dif_gpio_t *gpio, dif_gpio_pin_t pin,
                           bool *state);

/**
 * Reads from all pins.
 *
 * The value returned by this function is independent of the output enable
 * setting and includes the effects of the input noise filter and the load on
 * the pins.
 *
 * @param gpio A GPIO handle.
 * @param[out] state Pin values.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_read_all(const dif_gpio_t *gpio, dif_gpio_state_t *state);

/**
 * Writes to a pin.
 *
 * The actual value on the pin depends on the output enable setting.
 *
 * @param gpio A GPIO handle.
 * @param pin A GPIO pin.
 * @param state Value to write.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_write(const dif_gpio_t *gpio, dif_gpio_pin_t pin,
                            bool state);

/**
 * Writes to all pins.
 *
 * The actual values on the pins depend on the output enable setting.
 *
 * @param gpio A GPIO handle.
 * @param state Value to write.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_write_all(const dif_gpio_t *gpio, dif_gpio_state_t state);

/**
 * Writes to the pins identified by a mask.
 *
 * The actual values on the pins depend on the output enable setting.
 *
 * @param gpio A GPIO handle.
 * @param mask Mask that identifies the pins to write to.
 * @param state Value to write.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_write_masked(const dif_gpio_t *gpio, dif_gpio_mask_t mask,
                                   dif_gpio_state_t state);

/**
 * Sets output enable mode of a pin.
 *
 * @param gpio A GPIO handle.
 * @param pin A GPIO pin.
 * @param state Output mode of the pin.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_output_set_enabled(const dif_gpio_t *gpio,
                                         dif_gpio_pin_t pin,
                                         dif_toggle_t state);

/**
 * Sets output modes of all pins.
 *
 * @param gpio A GPIO handle.
 * @param state Output modes of the pins.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_output_set_enabled_all(const dif_gpio_t *gpio,
                                             dif_gpio_state_t state);

/**
 * Sets the output modes of the pins identified by a mask.
 *
 * @param gpio A GPIO handle.
 * @param mask Mask that identifies the pins whose output modes will be set.
 * @param state Output modes of the pins.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_output_set_enabled_masked(const dif_gpio_t *gpio,
                                                dif_gpio_mask_t mask,
                                                dif_gpio_state_t state);

/**
 * Enable noise filter for GPIO inputs.
 *
 * When enabled, changes in the pin value will be ignored unless stable
 * for 16 cycles.
 *
 * @param gpio A GPIO handle.
 * @param mask Mask that identifies pins to set the filter state of.
 * @param state The new toggle state for the filter.
 * @return The result of the operation.
 */
OT_WARN_UNUSED_RESULT
dif_result_t dif_gpio_input_noise_filter_set_enabled(const dif_gpio_t *gpio,
                                                     dif_gpio_mask_t mask,
                                                     dif_toggle_t state);

#ifdef __cplusplus
}  // extern "C"
#endif  // __cplusplus

#endif  // OPENTITAN_SW_DEVICE_LIB_DIF_DIF_GPIO_H_