serial_uniphier.c
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/*
* Copyright (C) 2012-2015 Panasonic Corporation
* Copyright (C) 2015-2016 Socionext Inc.
* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <linux/io.h>
#include <linux/serial_reg.h>
#include <linux/sizes.h>
#include <linux/errno.h>
#include <serial.h>
#include <fdtdec.h>
/*
* Note: Register map is slightly different from that of 16550.
*/
struct uniphier_serial {
u32 rx; /* In: Receive buffer */
#define tx rx /* Out: Transmit buffer */
u32 ier; /* Interrupt Enable Register */
u32 iir; /* In: Interrupt ID Register */
u32 char_fcr; /* Charactor / FIFO Control Register */
u32 lcr_mcr; /* Line/Modem Control Register */
#define LCR_SHIFT 8
#define LCR_MASK (0xff << (LCR_SHIFT))
u32 lsr; /* In: Line Status Register */
u32 msr; /* In: Modem Status Register */
u32 __rsv0;
u32 __rsv1;
u32 dlr; /* Divisor Latch Register */
};
struct uniphier_serial_private_data {
struct uniphier_serial __iomem *membase;
unsigned int uartclk;
};
#define uniphier_serial_port(dev) \
((struct uniphier_serial_private_data *)dev_get_priv(dev))->membase
static int uniphier_serial_setbrg(struct udevice *dev, int baudrate)
{
struct uniphier_serial_private_data *priv = dev_get_priv(dev);
struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
const unsigned int mode_x_div = 16;
unsigned int divisor;
divisor = DIV_ROUND_CLOSEST(priv->uartclk, mode_x_div * baudrate);
writel(divisor, &port->dlr);
return 0;
}
static int uniphier_serial_getc(struct udevice *dev)
{
struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
if (!(readl(&port->lsr) & UART_LSR_DR))
return -EAGAIN;
return readl(&port->rx);
}
static int uniphier_serial_putc(struct udevice *dev, const char c)
{
struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
if (!(readl(&port->lsr) & UART_LSR_THRE))
return -EAGAIN;
writel(c, &port->tx);
return 0;
}
static int uniphier_serial_pending(struct udevice *dev, bool input)
{
struct uniphier_serial __iomem *port = uniphier_serial_port(dev);
if (input)
return readl(&port->lsr) & UART_LSR_DR;
else
return !(readl(&port->lsr) & UART_LSR_THRE);
}
static int uniphier_serial_probe(struct udevice *dev)
{
DECLARE_GLOBAL_DATA_PTR;
struct uniphier_serial_private_data *priv = dev_get_priv(dev);
struct uniphier_serial __iomem *port;
fdt_addr_t base;
u32 tmp;
base = devfdt_get_addr(dev);
if (base == FDT_ADDR_T_NONE)
return -EINVAL;
port = devm_ioremap(dev, base, SZ_64);
if (!port)
return -ENOMEM;
priv->membase = port;
priv->uartclk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
"clock-frequency", 0);
tmp = readl(&port->lcr_mcr);
tmp &= ~LCR_MASK;
tmp |= UART_LCR_WLEN8 << LCR_SHIFT;
writel(tmp, &port->lcr_mcr);
return 0;
}
static const struct udevice_id uniphier_uart_of_match[] = {
{ .compatible = "socionext,uniphier-uart" },
{ /* sentinel */ }
};
static const struct dm_serial_ops uniphier_serial_ops = {
.setbrg = uniphier_serial_setbrg,
.getc = uniphier_serial_getc,
.putc = uniphier_serial_putc,
.pending = uniphier_serial_pending,
};
U_BOOT_DRIVER(uniphier_serial) = {
.name = "uniphier-uart",
.id = UCLASS_SERIAL,
.of_match = uniphier_uart_of_match,
.probe = uniphier_serial_probe,
.priv_auto_alloc_size = sizeof(struct uniphier_serial_private_data),
.ops = &uniphier_serial_ops,
};