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/*
* (C) Copyright 2015
* Kamil Lulko, <kamil.lulko@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <asm/io.h>
#include <serial.h>
#include <asm/arch/stm32.h>
#include <dm/platform_data/serial_stm32.h>
struct stm32_usart {
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;
#define MAX_SERIAL_PORTS 4
/*
* RCC USART specific definitions
*/
#define RCC_ENR_USART1EN (1 << 4)
#define RCC_ENR_USART2EN (1 << 17)
#define RCC_ENR_USART3EN (1 << 18)
#define RCC_ENR_USART6EN (1 << 5)
/* Array used to figure out which RCC bit needs to be set */
static const unsigned long usart_port_rcc_pairs[MAX_SERIAL_PORTS][2] = {
{ STM32_USART1_BASE, RCC_ENR_USART1EN },
{ STM32_USART2_BASE, RCC_ENR_USART2EN },
{ STM32_USART3_BASE, RCC_ENR_USART3EN },
{ STM32_USART6_BASE, RCC_ENR_USART6EN }
};
static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
{
struct stm32_serial_platdata *plat = dev->platdata;
struct stm32_usart *const usart = plat->base;
u32 clock, int_div, frac_div, tmp;
if (((u32)usart & STM32_BUS_MASK) == STM32_APB1PERIPH_BASE)
clock = clock_get(CLOCK_APB1);
else if (((u32)usart & STM32_BUS_MASK) == STM32_APB2PERIPH_BASE)
clock = clock_get(CLOCK_APB2);
else
return -EINVAL;
int_div = (25 * clock) / (4 * 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);
return 0;
}
static int stm32_serial_getc(struct udevice *dev)
{
struct stm32_serial_platdata *plat = dev->platdata;
struct stm32_usart *const usart = plat->base;
if ((readl(&usart->sr) & USART_SR_FLAG_RXNE) == 0)
return -EAGAIN;
return readl(&usart->dr);
}
static int stm32_serial_putc(struct udevice *dev, const char c)
{
struct stm32_serial_platdata *plat = dev->platdata;
struct stm32_usart *const usart = plat->base;
if ((readl(&usart->sr) & USART_SR_FLAG_TXE) == 0)
return -EAGAIN;
writel(c, &usart->dr);
return 0;
}
static int stm32_serial_pending(struct udevice *dev, bool input)
{
struct stm32_serial_platdata *plat = dev->platdata;
struct stm32_usart *const usart = plat->base;
if (input)
return readl(&usart->sr) & USART_SR_FLAG_RXNE ? 1 : 0;
else
return readl(&usart->sr) & USART_SR_FLAG_TXE ? 0 : 1;
}
static int stm32_serial_probe(struct udevice *dev)
{
struct stm32_serial_platdata *plat = dev->platdata;
struct stm32_usart *const usart = plat->base;
int usart_port = -1;
int i;
for (i = 0; i < MAX_SERIAL_PORTS; i++) {
if ((u32)usart == usart_port_rcc_pairs[i][0]) {
usart_port = i;
break;
}
}
if (usart_port == -1)
return -EINVAL;
if (((u32)usart & STM32_BUS_MASK) == STM32_APB1PERIPH_BASE)
setbits_le32(&STM32_RCC->apb1enr,
usart_port_rcc_pairs[usart_port][1]);
else if (((u32)usart & STM32_BUS_MASK) == STM32_APB2PERIPH_BASE)
setbits_le32(&STM32_RCC->apb2enr,
usart_port_rcc_pairs[usart_port][1]);
else
return -EINVAL;
setbits_le32(&usart->cr1, USART_CR1_RE | USART_CR1_TE | USART_CR1_UE);
return 0;
}
static const struct dm_serial_ops stm32_serial_ops = {
.putc = stm32_serial_putc,
.pending = stm32_serial_pending,
.getc = stm32_serial_getc,
.setbrg = stm32_serial_setbrg,
};
U_BOOT_DRIVER(serial_stm32) = {
.name = "serial_stm32",
.id = UCLASS_SERIAL,
.ops = &stm32_serial_ops,
.probe = stm32_serial_probe,
.flags = DM_FLAG_PRE_RELOC,
};
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