259 lines
7.3 KiB
C
259 lines
7.3 KiB
C
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/* Copyright 2014 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef __CROS_EC_USART_H
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#define __CROS_EC_USART_H
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/* STM32 USART driver for Chrome EC */
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#include "common.h"
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#include "consumer.h"
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#include "producer.h"
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#include "queue.h"
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#include <stdint.h>
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/*
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* Per-USART state stored in RAM. This structure will be zero initialized by
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* BSS init.
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*/
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struct usart_state {
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/*
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* Counter of bytes received and then dropped because of lack of space
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* in the RX queue.
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*/
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uint32_t rx_dropped;
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/*
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* Counter of the number of times an receive overrun condition is
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* detected. This will not usually be a count of the number of bytes
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* that were lost due to overrun conditions.
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*/
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uint32_t rx_overrun;
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};
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struct usart_config;
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struct usart_hw_ops {
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/*
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* The generic USART initialization code calls this function to allow
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* the variant HW specific code to perform any initialization. This
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* function is called before the USART is enabled, and should among
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* other things enable the USARTs interrupt.
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*/
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void (*enable)(struct usart_config const *config);
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/*
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* The generic USART shutdown code calls this function, allowing the
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* variant specific code an opportunity to do any variant specific
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* shutdown tasks.
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*/
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void (*disable)(struct usart_config const *config);
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};
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/*
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* The usart_rx/usart_tx structures contain functions pointers for the
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* interrupt handler and producer/consumer operations required to implement a
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* particular RX/TX strategy.
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*
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* These structures are defined by the various RX/TX implementations, and are
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* used to initialize the usart_config structure to configure the USART driver
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* for interrupt or DMA based transfer.
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*/
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struct usart_rx {
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void (*init)(struct usart_config const *config);
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void (*interrupt)(struct usart_config const *config);
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/*
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* Print to the console any per-strategy diagnostic information, this
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* is used by the usart_info command. This can be NULL if there is
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* nothing interesting to display.
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*/
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void (*info)(struct usart_config const *config);
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struct producer_ops producer_ops;
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};
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struct usart_tx {
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void (*init)(struct usart_config const *config);
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void (*interrupt)(struct usart_config const *config);
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/*
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* Print to the console any per-strategy diagnostic information, this
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* is used by the usart_info command. This can be NULL if there is
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* nothing interesting to display.
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*/
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void (*info)(struct usart_config const *config);
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struct consumer_ops consumer_ops;
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};
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extern struct usart_rx const usart_rx_interrupt;
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extern struct usart_tx const usart_tx_interrupt;
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/*
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* Per-USART hardware configuration stored in flash. Instances of this
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* structure are provided by each variants driver, one per physical USART.
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*/
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struct usart_hw_config {
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int index;
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intptr_t base;
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int irq;
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uint32_t volatile *clock_register;
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uint32_t clock_enable;
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struct usart_hw_ops const *ops;
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};
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/*
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* Compile time Per-USART configuration stored in flash. Instances of this
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* structure are provided by the user of the USART. This structure binds
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* together all information required to operate a USART.
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*/
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struct usart_config {
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/*
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* Pointer to USART HW configuration. There is one HW configuration
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* per physical USART.
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*/
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struct usart_hw_config const *hw;
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struct usart_rx const *rx;
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struct usart_tx const *tx;
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/*
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* Pointer to USART state structure. The state structure maintains per
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* USART information.
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*/
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struct usart_state volatile *state;
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/*
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* Baud rate for USART.
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*/
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int baud;
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/* Other flags (rx/tx inversion, half-duplex). */
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#define USART_CONFIG_FLAG_RX_INV BIT(0)
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#define USART_CONFIG_FLAG_TX_INV BIT(1)
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#define USART_CONFIG_FLAG_HDSEL BIT(2)
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unsigned int flags;
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struct consumer consumer;
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struct producer producer;
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};
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/*
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* Convenience macro for defining USARTs and their associated state and buffers.
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* NAME is used to construct the names of the usart_state struct, and
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* usart_config struct, the latter is just called NAME.
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*
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* HW is the name of the usart_hw_config provided by the variant specific code.
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*
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* RX_QUEUE and TX_QUEUE are the names of the RX and TX queues that this USART
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* should write to and read from respectively.
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*/
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/*
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* The following assertions can not be made because they require access to
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* non-const fields, but should be kept in mind.
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*
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* BUILD_ASSERT(RX_QUEUE.unit_bytes == 1);
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* BUILD_ASSERT(TX_QUEUE.unit_bytes == 1);
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*/
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#define USART_CONFIG(HW, RX, TX, BAUD, FLAGS, RX_QUEUE, TX_QUEUE) \
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((struct usart_config const) { \
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.hw = &HW, \
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.rx = &RX, \
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.tx = &TX, \
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.state = &((struct usart_state){}), \
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.baud = BAUD, \
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.flags = FLAGS, \
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.consumer = { \
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.queue = &TX_QUEUE, \
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.ops = &TX.consumer_ops, \
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}, \
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.producer = { \
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.queue = &RX_QUEUE, \
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.ops = &RX.producer_ops, \
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}, \
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})
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/*
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* Initialize the given USART. Once init is finished the USART streams are
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* available for operating on.
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*/
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void usart_init(struct usart_config const *config);
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/*
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* Shutdown the given USART.
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*/
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void usart_shutdown(struct usart_config const *config);
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/*
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* Handle a USART interrupt. The per-variant USART code creates bindings
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* for the variants interrupts to call this generic USART interrupt handler
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* with the appropriate usart_config.
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*/
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void usart_interrupt(struct usart_config const *config);
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/*
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* These are HW specific baud rate calculation and setting functions that the
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* peripheral variant code uses during initialization and clock frequency
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* change. The baud rate divisor input frequency is passed in Hertz.
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*/
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void usart_set_baud_f0_l(struct usart_config const *config, int baud,
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int frequency_hz);
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void usart_set_baud_f(struct usart_config const *config, int baud,
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int frequency_hz);
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/*
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* Allow specification of parity for this usart.
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* parity is 0: none, 1: odd, 2: even.
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*/
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void usart_set_parity(struct usart_config const *config, int parity);
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/*
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* Check parity for this usart.
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* parity is 0: none, 1: odd, 2: even.
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*/
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int usart_get_parity(struct usart_config const *config);
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/*
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* Set baud rate for this usart. Note that baud rate will get reset on
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* core frequency change, so this only makes sense if the board never
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* goes to deep idle.
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*/
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void usart_set_baud(struct usart_config const *config, int baud);
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/*
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* Different families provide different ways of clearing the transmit complete
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* flag. This function will be provided by the family specific implementation.
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*/
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void usart_clear_tc(struct usart_config const *config);
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/*
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* Each family implementation provides the usart_get_configs function to access
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* a read only list of the configs that are currently enabled.
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*/
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struct usart_configs {
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/*
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* The family's usart_config array, entries in the array for disabled
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* configs will be NULL, enabled configs will point to the usart_config
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* that was enabled. And the following will be true:
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*
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* configs[i]->hw->index == i;
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*/
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struct usart_config const * const *configs;
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/*
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* The total possible number of configs that this family supports.
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* This will be the same as the number of usart_hw structs that the
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* family provides in its family specific usart header.
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*/
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size_t count;
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};
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struct usart_configs usart_get_configs(void);
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#endif /* __CROS_EC_USART_H */
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