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u-boot/drivers/serial/serial_stm32.c
Patrice Chotard f828fa4d82 serial: serial_stm32: Add reset support 
In some cases, UART is configured by early boot stage.
To be sure of the initial state of UART and to avoid
spurious chars on console, reset the serial block before
configuring it.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-12-15 11:49:56 -05:00

286 lines
7.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016, STMicroelectronics - All Rights Reserved
* Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <reset.h>
#include <serial.h>
#include <watchdog.h>
#include <asm/io.h>
#include <asm/arch/stm32.h>
#include "serial_stm32.h"
static void _stm32_serial_setbrg(fdt_addr_t base,
struct stm32_uart_info *uart_info,
u32 clock_rate,
int baudrate)
{
bool stm32f4 = uart_info->stm32f4;
u32 int_div, mantissa, fraction, oversampling;
int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
if (int_div < 16) {
oversampling = 8;
setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
} else {
oversampling = 16;
clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
}
mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT;
fraction = int_div % oversampling;
writel(mantissa | fraction, base + BRR_OFFSET(stm32f4));
}
static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
_stm32_serial_setbrg(plat->base, plat->uart_info,
plat->clock_rate, baudrate);
return 0;
}
static int stm32_serial_setconfig(struct udevice *dev, uint serial_config)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
u8 uart_enable_bit = plat->uart_info->uart_enable_bit;
u32 cr1 = plat->base + CR1_OFFSET(stm32f4);
u32 config = 0;
uint parity = SERIAL_GET_PARITY(serial_config);
uint bits = SERIAL_GET_BITS(serial_config);
uint stop = SERIAL_GET_STOP(serial_config);
/*
* only parity config is implemented, check if other serial settings
* are the default one.
* (STM32F4 serial IP didn't support parity setting)
*/
if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP || stm32f4)
return -ENOTSUPP; /* not supported in driver*/
clrbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
/* update usart configuration (uart need to be disable)
* PCE: parity check enable
* PS : '0' : Even / '1' : Odd
* M[1:0] = '00' : 8 Data bits
* M[1:0] = '01' : 9 Data bits with parity
*/
switch (parity) {
default:
case SERIAL_PAR_NONE:
config = 0;
break;
case SERIAL_PAR_ODD:
config = USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0;
break;
case SERIAL_PAR_EVEN:
config = USART_CR1_PCE | USART_CR1_M0;
break;
}
clrsetbits_le32(cr1,
USART_CR1_PCE | USART_CR1_PS | USART_CR1_M1 |
USART_CR1_M0,
config);
setbits_le32(cr1, USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
return 0;
}
static int stm32_serial_getc(struct udevice *dev)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
u32 isr = readl(base + ISR_OFFSET(stm32f4));
if ((isr & USART_ISR_RXNE) == 0)
return -EAGAIN;
if (isr & (USART_ISR_PE | USART_ISR_ORE)) {
if (!stm32f4)
setbits_le32(base + ICR_OFFSET,
USART_ICR_PCECF | USART_ICR_ORECF);
else
readl(base + RDR_OFFSET(stm32f4));
return -EIO;
}
return readl(base + RDR_OFFSET(stm32f4));
}
static int _stm32_serial_putc(fdt_addr_t base,
struct stm32_uart_info *uart_info,
const char c)
{
bool stm32f4 = uart_info->stm32f4;
if ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE) == 0)
return -EAGAIN;
writel(c, base + TDR_OFFSET(stm32f4));
return 0;
}
static int stm32_serial_putc(struct udevice *dev, const char c)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
return _stm32_serial_putc(plat->base, plat->uart_info, c);
}
static int stm32_serial_pending(struct udevice *dev, bool input)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
if (input)
return readl(base + ISR_OFFSET(stm32f4)) &
USART_ISR_RXNE ? 1 : 0;
else
return readl(base + ISR_OFFSET(stm32f4)) &
USART_ISR_TXE ? 0 : 1;
}
static void _stm32_serial_init(fdt_addr_t base,
struct stm32_uart_info *uart_info)
{
bool stm32f4 = uart_info->stm32f4;
u8 uart_enable_bit = uart_info->uart_enable_bit;
/* Disable uart-> enable fifo -> enable uart */
clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
BIT(uart_enable_bit));
if (uart_info->has_fifo)
setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_FIFOEN);
setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
BIT(uart_enable_bit));
}
static int stm32_serial_probe(struct udevice *dev)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
struct clk clk;
struct reset_ctl reset;
int ret;
plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
ret = clk_get_by_index(dev, 0, &clk);
if (ret < 0)
return ret;
ret = clk_enable(&clk);
if (ret) {
dev_err(dev, "failed to enable clock\n");
return ret;
}
ret = reset_get_by_index(dev, 0, &reset);
if (!ret) {
reset_assert(&reset);
udelay(2);
reset_deassert(&reset);
}
plat->clock_rate = clk_get_rate(&clk);
if (plat->clock_rate < 0) {
clk_disable(&clk);
return plat->clock_rate;
};
_stm32_serial_init(plat->base, plat->uart_info);
return 0;
}
static const struct udevice_id stm32_serial_id[] = {
{ .compatible = "st,stm32-uart", .data = (ulong)&stm32f4_info},
{ .compatible = "st,stm32f7-uart", .data = (ulong)&stm32f7_info},
{ .compatible = "st,stm32h7-uart", .data = (ulong)&stm32h7_info},
{}
};
static int stm32_serial_ofdata_to_platdata(struct udevice *dev)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
plat->base = devfdt_get_addr(dev);
if (plat->base == FDT_ADDR_T_NONE)
return -EINVAL;
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,
.setconfig = stm32_serial_setconfig
};
U_BOOT_DRIVER(serial_stm32) = {
.name = "serial_stm32",
.id = UCLASS_SERIAL,
.of_match = of_match_ptr(stm32_serial_id),
.ofdata_to_platdata = of_match_ptr(stm32_serial_ofdata_to_platdata),
.platdata_auto_alloc_size = sizeof(struct stm32x7_serial_platdata),
.ops = &stm32_serial_ops,
.probe = stm32_serial_probe,
#if !CONFIG_IS_ENABLED(OF_CONTROL)
.flags = DM_FLAG_PRE_RELOC,
#endif
};
#ifdef CONFIG_DEBUG_UART_STM32
#include <debug_uart.h>
static inline struct stm32_uart_info *_debug_uart_info(void)
{
struct stm32_uart_info *uart_info;
#if defined(CONFIG_STM32F4)
uart_info = &stm32f4_info;
#elif defined(CONFIG_STM32F7)
uart_info = &stm32f7_info;
#else
uart_info = &stm32h7_info;
#endif
return uart_info;
}
static inline void _debug_uart_init(void)
{
fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
struct stm32_uart_info *uart_info = _debug_uart_info();
_stm32_serial_init(base, uart_info);
_stm32_serial_setbrg(base, uart_info,
CONFIG_DEBUG_UART_CLOCK,
CONFIG_BAUDRATE);
printf("DEBUG done\n");
}
static inline void _debug_uart_putc(int c)
{
fdt_addr_t base = CONFIG_DEBUG_UART_BASE;
struct stm32_uart_info *uart_info = _debug_uart_info();
while (_stm32_serial_putc(base, uart_info, c) == -EAGAIN)
WATCHDOG_RESET();
}
DEBUG_UART_FUNCS
#endif
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