serial_cortina.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2020 Cortina-Access Ltd.
* Common UART Driver for Cortina Access CAxxxx line of SoCs
*
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <watchdog.h>
#include <asm/io.h>
#include <serial.h>
#include <linux/compiler.h>
/* Register definitions */
#define UCFG 0x00 /* UART config register */
#define UFC 0x04 /* Flow Control */
#define URX_SAMPLE 0x08 /* UART RX Sample register */
#define URT_TUNE 0x0C /* Fine tune of UART clk */
#define UTX_DATA 0x10 /* UART TX Character data */
#define URX_DATA 0x14 /* UART RX Character data */
#define UINFO 0x18 /* UART Info */
#define UINT_EN0 0x1C /* UART Interrupt enable 0 */
#define UINT_EN1 0x20 /* UART Interrupt enable 1 */
#define UINT0 0x24 /* UART Interrupt 0 setting/clearing */
#define UINT1 0x28 /* UART Interrupt 1 setting/clearing */
#define UINT_STAT 0x2C /* UART Interrupt Status */
/* UART Control Register Bit Fields */
#define UCFG_BAUD_COUNT_MASK 0xFFFFFF00
#define UCFG_BAUD_COUNT(x) ((x << 8) & UCFG_BAUD_COUNT_MASK)
#define UCFG_EN BIT(7)
#define UCFG_RX_EN BIT(6)
#define UCFG_TX_EN BIT(5)
#define UCFG_PARITY_EN BIT(4)
#define UCFG_PARITY_SEL BIT(3)
#define UCFG_2STOP_BIT BIT(2)
#define UCFG_CNT1 BIT(1)
#define UCFG_CNT0 BIT(0)
#define UCFG_CHAR_5 0
#define UCFG_CHAR_6 1
#define UCFG_CHAR_7 2
#define UCFG_CHAR_8 3
#define UINFO_TX_FIFO_EMPTY BIT(3)
#define UINFO_TX_FIFO_FULL BIT(2)
#define UINFO_RX_FIFO_EMPTY BIT(1)
#define UINFO_RX_FIFO_FULL BIT(0)
#define UINT_RX_NON_EMPTY BIT(6)
#define UINT_TX_EMPTY BIT(5)
#define UINT_RX_UNDERRUN BIT(4)
#define UINT_RX_OVERRUN BIT(3)
#define UINT_RX_PARITY_ERR BIT(2)
#define UINT_RX_STOP_ERR BIT(1)
#define UINT_TX_OVERRUN BIT(0)
#define UINT_MASK_ALL 0x7F
struct ca_uart_priv {
void __iomem *base;
};
int ca_serial_setbrg(struct udevice *dev, int baudrate)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
unsigned int uart_ctrl, baud, sample;
baud = CORTINA_UART_CLOCK / baudrate;
uart_ctrl = readl(priv->base + UCFG);
uart_ctrl &= ~UCFG_BAUD_COUNT_MASK;
uart_ctrl |= UCFG_BAUD_COUNT(baud);
writel(uart_ctrl, priv->base + UCFG);
sample = baud / 2;
sample = (sample < 7) ? 7 : sample;
writel(sample, priv->base + URX_SAMPLE);
return 0;
}
static int ca_serial_getc(struct udevice *dev)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
int ch;
ch = readl(priv->base + URX_DATA) & 0xFF;
return (int)ch;
}
static int ca_serial_putc(struct udevice *dev, const char ch)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
unsigned int status;
/* Retry if TX FIFO full */
status = readl(priv->base + UINFO);
if (status & UINFO_TX_FIFO_FULL)
return -EAGAIN;
writel(ch, priv->base + UTX_DATA);
return 0;
}
static int ca_serial_pending(struct udevice *dev, bool input)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
unsigned int status;
status = readl(priv->base + UINFO);
if (input)
return (status & UINFO_RX_FIFO_EMPTY) ? 0 : 1;
else
return (status & UINFO_TX_FIFO_FULL) ? 1 : 0;
}
static int ca_serial_probe(struct udevice *dev)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
u32 uart_ctrl;
/* Set data, parity and stop bits */
uart_ctrl = UCFG_EN | UCFG_TX_EN | UCFG_RX_EN | UCFG_CHAR_8;
writel(uart_ctrl, priv->base + UCFG);
return 0;
}
static int ca_serial_ofdata_to_platdata(struct udevice *dev)
{
struct ca_uart_priv *priv = dev_get_priv(dev);
priv->base = dev_remap_addr_index(dev, 0);
if (!priv->base)
return -ENOENT;
return 0;
}
static const struct dm_serial_ops ca_serial_ops = {
.putc = ca_serial_putc,
.pending = ca_serial_pending,
.getc = ca_serial_getc,
.setbrg = ca_serial_setbrg,
};
static const struct udevice_id ca_serial_ids[] = {
{.compatible = "cortina,ca-uart"},
{}
};
U_BOOT_DRIVER(serial_cortina) = {
.name = "serial_cortina",
.id = UCLASS_SERIAL,
.of_match = ca_serial_ids,
.ofdata_to_platdata = ca_serial_ofdata_to_platdata,
.priv_auto_alloc_size = sizeof(struct ca_uart_priv),
.probe = ca_serial_probe,
.ops = &ca_serial_ops
};