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/* Copyright 2014 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "usart-stm32f0.h"
#include "clock.h"
#include "common.h"
#include "compile_time_macros.h"
#include "hooks.h"
#include "registers.h"
#include "task.h"
#include "util.h"
/*
* This configs array stores the currently active usart_config structure for
* each USART, an entry will be NULL if no USART driver is initialized for the
* corresponding hardware instance.
*/
#define STM32_USARTS_MAX 4
static struct usart_config const *configs[STM32_USARTS_MAX];
struct usart_configs usart_get_configs(void)
{
return (struct usart_configs){ configs, ARRAY_SIZE(configs) };
}
static void usart_variant_enable(struct usart_config const *config)
{
/*
* Make sure we register this config before enabling the HW.
* If we did it the other way around the FREQ_CHANGE hook could be
* called before we update the configs array and we would miss the
* clock frequency change event, leaving our baud rate divisor wrong.
*/
configs[config->hw->index] = config;
usart_set_baud(config, config->baud);
task_enable_irq(config->hw->irq);
}
void usart_set_baud(struct usart_config const *config, int baud)
{
usart_set_baud_f0_l(config, baud, clock_get_freq());
}
static void usart_variant_disable(struct usart_config const *config)
{
int index = config->hw->index;
/*
* Only disable the shared interrupt for USART3/4 if both USARTs are
* now disabled.
*/
if ((index == 0) || (index == 1) ||
(index == 2 && configs[3] == NULL) ||
(index == 3 && configs[2] == NULL))
task_disable_irq(config->hw->irq);
configs[index] = NULL;
}
static struct usart_hw_ops const usart_variant_hw_ops = {
.enable = usart_variant_enable,
.disable = usart_variant_disable,
};
static void freq_change(void)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(configs); ++i)
if (configs[i])
usart_set_baud_f0_l(configs[i], configs[i]->baud,
clock_get_freq());
}
DECLARE_HOOK(HOOK_FREQ_CHANGE, freq_change, HOOK_PRIO_DEFAULT);
void usart_clear_tc(struct usart_config const *config)
{
/*
* ST reference code does blind write to this register, as is usual
* with the "write 1 to clear" convention, despite the datasheet
* listing the bits as "keep at reset value", (which we assume is due
* to copying from the description of reserved bits in read/write
* registers.)
*/
STM32_USART_ICR(config->hw->base) = STM32_USART_ICR_TCCF;
}
/*
* USART interrupt bindings. These functions can not be defined as static or
* they will be removed by the linker because of the way that DECLARE_IRQ works.
*/
#if defined(CONFIG_STREAM_USART1)
struct usart_hw_config const usart1_hw = {
.index = 0,
.base = STM32_USART1_BASE,
.irq = STM32_IRQ_USART1,
.clock_register = &STM32_RCC_APB2ENR,
.clock_enable = STM32_RCC_PB2_USART1,
.ops = &usart_variant_hw_ops,
};
static void usart1_interrupt(void)
{
usart_interrupt(configs[0]);
}
DECLARE_IRQ(STM32_IRQ_USART1, usart1_interrupt, 2);
#endif
#if defined(CONFIG_STREAM_USART2)
struct usart_hw_config const usart2_hw = {
.index = 1,
.base = STM32_USART2_BASE,
.irq = STM32_IRQ_USART2,
.clock_register = &STM32_RCC_APB1ENR,
.clock_enable = STM32_RCC_PB1_USART2,
.ops = &usart_variant_hw_ops,
};
static void usart2_interrupt(void)
{
usart_interrupt(configs[1]);
}
DECLARE_IRQ(STM32_IRQ_USART2, usart2_interrupt, 2);
#endif
#if defined(CONFIG_STREAM_USART3)
struct usart_hw_config const usart3_hw = {
.index = 2,
.base = STM32_USART3_BASE,
.irq = STM32_IRQ_USART3_4,
.clock_register = &STM32_RCC_APB1ENR,
.clock_enable = STM32_RCC_PB1_USART3,
.ops = &usart_variant_hw_ops,
};
#endif
#if defined(CONFIG_STREAM_USART4)
struct usart_hw_config const usart4_hw = {
.index = 3,
.base = STM32_USART4_BASE,
.irq = STM32_IRQ_USART3_4,
.clock_register = &STM32_RCC_APB1ENR,
.clock_enable = STM32_RCC_PB1_USART4,
.ops = &usart_variant_hw_ops,
};
#endif
#if defined(CONFIG_STREAM_USART3) || defined(CONFIG_STREAM_USART4)
static void usart3_4_interrupt(void)
{
/*
* This interrupt handler could be called with one of these configs
* not initialized, so we need to check here and only call the generic
* USART interrupt handler for initialized configs.
*/
if (configs[2])
usart_interrupt(configs[2]);
if (configs[3])
usart_interrupt(configs[3]);
}
DECLARE_IRQ(STM32_IRQ_USART3_4, usart3_4_interrupt, 2);
#endif
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