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/*
* (C) Copyright 2015
* Kamil Lulko, <rev13@wp.pl>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <serial.h>
#include <asm/arch/stm32.h>
#define STM32_USART1_BASE (STM32_APB2PERIPH_BASE + 0x1000)
#define RCC_APB2ENR_USART1EN (1 << 4)
#define USART_BASE STM32_USART1_BASE
#define RCC_USART_ENABLE RCC_APB2ENR_USART1EN
struct stm32_serial {
u32 sr;
u32 dr;
u32 brr;
u32 cr1;
u32 cr2;
u32 cr3;
u32 gtpr;
};
#define USART_CR1_RE (1 << 2)
#define USART_CR1_TE (1 << 3)
#define USART_CR1_UE (1 << 13)
#define USART_SR_FLAG_RXNE (1 << 5)
#define USART_SR_FLAG_TXE (1 << 7)
#define USART_BRR_F_MASK 0xF
#define USART_BRR_M_SHIFT 4
#define USART_BRR_M_MASK 0xFFF0
DECLARE_GLOBAL_DATA_PTR;
static void stm32_serial_setbrg(void)
{
serial_init();
}
static int stm32_serial_init(void)
{
struct stm32_serial *usart = (struct stm32_serial *)USART_BASE;
u32 clock, int_div, frac_div, tmp;
if ((USART_BASE & STM32_BUS_MASK) == STM32_APB1PERIPH_BASE) {
setbits_le32(&STM32_RCC->apb1enr, RCC_USART_ENABLE);
clock = clock_get(CLOCK_APB1);
} else if ((USART_BASE & STM32_BUS_MASK) == STM32_APB2PERIPH_BASE) {
setbits_le32(&STM32_RCC->apb2enr, RCC_USART_ENABLE);
clock = clock_get(CLOCK_APB2);
} else {
return -1;
}
int_div = (25 * clock) / (4 * gd->baudrate);
tmp = ((int_div / 100) << USART_BRR_M_SHIFT) & USART_BRR_M_MASK;
frac_div = int_div - (100 * (tmp >> USART_BRR_M_SHIFT));
tmp |= (((frac_div * 16) + 50) / 100) & USART_BRR_F_MASK;
writel(tmp, &usart->brr);
setbits_le32(&usart->cr1, USART_CR1_RE | USART_CR1_TE | USART_CR1_UE);
return 0;
}
static int stm32_serial_getc(void)
{
struct stm32_serial *usart = (struct stm32_serial *)USART_BASE;
while ((readl(&usart->sr) & USART_SR_FLAG_RXNE) == 0)
;
return readl(&usart->dr);
}
static void stm32_serial_putc(const char c)
{
struct stm32_serial *usart = (struct stm32_serial *)USART_BASE;
while ((readl(&usart->sr) & USART_SR_FLAG_TXE) == 0)
;
writel(c, &usart->dr);
}
static int stm32_serial_tstc(void)
{
struct stm32_serial *usart = (struct stm32_serial *)USART_BASE;
u8 ret;
ret = readl(&usart->sr) & USART_SR_FLAG_RXNE;
return ret;
}
static struct serial_device stm32_serial_drv = {
.name = "stm32_serial",
.start = stm32_serial_init,
.stop = NULL,
.setbrg = stm32_serial_setbrg,
.putc = stm32_serial_putc,
.puts = default_serial_puts,
.getc = stm32_serial_getc,
.tstc = stm32_serial_tstc,
};
void stm32_serial_initialize(void)
{
serial_register(&stm32_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &stm32_serial_drv;
}
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