stm32f4: Add serial driver

Signed-off-by: Kamil Lulko <rev13@wp.pl>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index b385852eee4d94d19a6163570f4b45bc2f6c819a..d183eedbcb3f8598c82968092c6bf493208b1f23 100644 (file)
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_TEGRA_SERIAL) += serial_tegra.o
 obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o
 obj-$(CONFIG_OMAP_SERIAL) += serial_omap.o
 obj-$(CONFIG_X86_SERIAL) += serial_x86.o
+obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o
 
 ifndef CONFIG_SPL_BUILD
 obj-$(CONFIG_USB_TTY) += usbtty.o

diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 9f78492298df2612157ea515eb10ca62ccf2dda8..699c410d6635bf0c8e1f49a8fc614c34c34bb3c6 100644 (file)
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -154,6 +154,7 @@ serial_initfunc(sa1100_serial_initialize);
 serial_initfunc(sandbox_serial_initialize);
 serial_initfunc(sconsole_serial_initialize);
 serial_initfunc(sh_serial_initialize);
+serial_initfunc(stm32_serial_initialize);
 serial_initfunc(uartlite_serial_initialize);
 serial_initfunc(zynq_serial_initialize);
 
@@ -246,6 +247,7 @@ void serial_initialize(void)
        sandbox_serial_initialize();
        sconsole_serial_initialize();
        sh_serial_initialize();
+       stm32_serial_initialize();
        uartlite_serial_initialize();
        zynq_serial_initialize();
 

diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
new file mode 100644 (file)
index 0000000..3c80096
--- /dev/null
+++ b/drivers/serial/serial_stm32.c
@@ -0,0 +1,117 @@
+/*
+ * (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;
+}