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serial: stm32: Add debug uart support

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Add support for early debug printf, before the availability of
driver model and device tree support.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
lime2-spi
Patrick Delaunay 6 years ago committed by Tom Rini
parent 246a5e5fc2
commit 215c8bed12
2 changed files with 92 additions and 22 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 9
      drivers/serial/Kconfig
  2. 105
      drivers/serial/serial_stm32.c

9
drivers/serial/Kconfig
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@ -324,6 +324,15 @@ config DEBUG_UART_MXC
will need to provide parameters to make this work. The driver will
be available until the real driver model serial is running.
config DEBUG_UART_STM32
bool "STMicroelectronics STM32"
depends on STM32_SERIAL
help
Select this to enable a debug UART using the serial_stm32 driver
You will need to provide parameters to make this work.
The driver will be available until the real driver model
serial is running.
config DEBUG_UART_UNIPHIER
bool "UniPhier on-chip UART"
depends on ARCH_UNIPHIER

105
drivers/serial/serial_stm32.c
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@ -7,19 +7,21 @@
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <asm/io.h>
#include <serial.h>
#include <watchdog.h>
#include <asm/io.h>
#include <asm/arch/stm32.h>
#include "serial_stm32.h"
static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
static void _stm32_serial_setbrg(fdt_addr_t base,
struct stm32_uart_info *uart_info,
u32 clock_rate,
int baudrate)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
bool stm32f4 = uart_info->stm32f4;
u32 int_div, mantissa, fraction, oversampling;
int_div = DIV_ROUND_CLOSEST(plat->clock_rate, baudrate);
int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
if (int_div < 16) {
oversampling = 8;
@ -33,6 +35,14 @@ static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
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;
}
@ -58,11 +68,11 @@ static int stm32_serial_getc(struct udevice *dev)
return readl(base + RDR_OFFSET(stm32f4));
}
static int stm32_serial_putc(struct udevice *dev, const char c)
static int _stm32_serial_putc(fdt_addr_t base,
struct stm32_uart_info *uart_info,
const char c)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
bool stm32f4 = uart_info->stm32f4;
if ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_FLAG_TXE) == 0)
return -EAGAIN;
@ -72,6 +82,13 @@ static int stm32_serial_putc(struct udevice *dev, const char c)
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);
@ -86,18 +103,28 @@ static int stm32_serial_pending(struct udevice *dev, bool input)
USART_ISR_FLAG_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;
fdt_addr_t base = plat->base;
int ret;
bool stm32f4;
u8 uart_enable_bit;
plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
stm32f4 = plat->uart_info->stm32f4;
uart_enable_bit = plat->uart_info->uart_enable_bit;
ret = clk_get_by_index(dev, 0, &clk);
if (ret < 0)
@ -115,13 +142,7 @@ static int stm32_serial_probe(struct udevice *dev)
return plat->clock_rate;
};
/* Disable uart-> enable fifo-> enable uart */
clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
BIT(uart_enable_bit));
if (plat->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));
_stm32_serial_init(plat->base, plat->uart_info);
return 0;
}
@ -161,3 +182,43 @@ U_BOOT_DRIVER(serial_stm32) = {
.probe = stm32_serial_probe,
.flags = DM_FLAG_PRE_RELOC,
};
#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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