serial_stm32.c
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/*
* Copyright (C) 2016, STMicroelectronics - All Rights Reserved
* Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <asm/io.h>
#include <serial.h>
#include <asm/arch/stm32.h>
#include "serial_stm32.h"
DECLARE_GLOBAL_DATA_PTR;
static int stm32_serial_setbrg(struct udevice *dev, int baudrate)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
u32 int_div, mantissa, fraction, oversampling;
int_div = DIV_ROUND_CLOSEST(plat->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));
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;
if ((readl(base + ISR_OFFSET(stm32f4)) & USART_SR_FLAG_RXNE) == 0)
return -EAGAIN;
return readl(base + RDR_OFFSET(stm32f4));
}
static int stm32_serial_putc(struct udevice *dev, const char c)
{
struct stm32x7_serial_platdata *plat = dev_get_platdata(dev);
bool stm32f4 = plat->uart_info->stm32f4;
fdt_addr_t base = plat->base;
if ((readl(base + ISR_OFFSET(stm32f4)) & USART_SR_FLAG_TXE) == 0)
return -EAGAIN;
writel(c, base + TDR_OFFSET(stm32f4));
return 0;
}
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_SR_FLAG_RXNE ? 1 : 0;
else
return readl(base + ISR_OFFSET(stm32f4)) &
USART_SR_FLAG_TXE ? 0 : 1;
}
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)
return ret;
ret = clk_enable(&clk);
if (ret) {
dev_err(dev, "failed to enable clock\n");
return ret;
}
plat->clock_rate = clk_get_rate(&clk);
if (plat->clock_rate < 0) {
clk_disable(&clk);
return plat->clock_rate;
};
/* Disable uart-> disable overrun-> enable uart */
clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_RE | USART_CR1_TE |
BIT(uart_enable_bit));
if (plat->uart_info->has_overrun_disable)
setbits_le32(base + CR3_OFFSET(stm32f4), USART_CR3_OVRDIS);
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));
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,
};
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,
.flags = DM_FLAG_PRE_RELOC,
};