serial: stm32: Add debug uart support

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>

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 87779098608102e5d7bab8bfe3791fe2e7d21350..2940bd05dc3f939c8e76e9a00dfd4ac6f9e150a6 100644 (file)
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -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.
 
          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
 config DEBUG_UART_UNIPHIER
        bool "UniPhier on-chip UART"
        depends on ARCH_UNIPHIER

diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index 6717ffaaa5b9aed6a06fa6ab3e10b4024b6fb94c..724d6f967246d35f48990f84523aa71c076bea56 100644 (file)
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -7,19 +7,21 @@
 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <common.h>
 #include <clk.h>
 #include <dm.h>

-#include <asm/io.h>

 #include <serial.h>
 #include <serial.h>

+#include <watchdog.h>
+#include <asm/io.h>

 #include <asm/arch/stm32.h>
 #include "serial_stm32.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;
 
        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;
 
        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));
        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;
 }
 
        return 0;
 }


@@ -58,11 +68,11 @@ static int stm32_serial_getc(struct udevice *dev)
        return readl(base + RDR_OFFSET(stm32f4));
 }
 
        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;
 
        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;
 }
 
        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);
 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;
 }
 
                        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;
 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;
        int ret;

-       bool stm32f4;
-       u8 uart_enable_bit;

 
        plat->uart_info = (struct stm32_uart_info *)dev_get_driver_data(dev);
 
        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)
 
        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;
        };
 
                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;
 }
 
        return 0;
 }


@@ -161,3 +182,43 @@ U_BOOT_DRIVER(serial_stm32) = {
        .probe = stm32_serial_probe,
        .flags = DM_FLAG_PRE_RELOC,
 };
        .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