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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
*
*/
#include <common.h>
#include <init.h>
#include <io.h>
#define UART_RXTX 0x00
#define UART_TXFULL 0x04
#define UART_RXEMPTY 0x08
#define UART_EV_PENDING 0x10
#define UART_EV_RX (1 << 1)
static inline uint32_t litex_serial_readb(struct console_device *cdev,
uint32_t offset)
{
void __iomem *base = cdev->dev->priv;
return readb(base + offset);
}
static inline void litex_serial_writeb(struct console_device *cdev,
uint32_t value, uint32_t offset)
{
void __iomem *base = cdev->dev->priv;
writeb(value, base + offset);
}
static void litex_serial_putc(struct console_device *cdev, char c)
{
while (litex_serial_readb(cdev, UART_TXFULL))
;
litex_serial_writeb(cdev, c, UART_RXTX);
}
static int litex_serial_getc(struct console_device *cdev)
{
int c;
while (litex_serial_readb(cdev, UART_RXEMPTY))
;
c = litex_serial_readb(cdev, UART_RXTX);
/* refresh UART_RXEMPTY by writing UART_EV_RX to UART_EV_PENDING */
litex_serial_writeb(cdev, UART_EV_RX, UART_EV_PENDING);
return c;
}
static int litex_serial_tstc(struct console_device *cdev)
{
return !litex_serial_readb(cdev, UART_RXEMPTY);
}
static int litex_serial_probe(struct device *dev)
{
struct resource *iores;
struct console_device *cdev;
cdev = xzalloc(sizeof(struct console_device));
iores = dev_request_mem_resource(dev, 0);
if (IS_ERR(iores))
return PTR_ERR(iores);
dev->priv = IOMEM(iores->start);
cdev->dev = dev;
cdev->tstc = &litex_serial_tstc;
cdev->putc = &litex_serial_putc;
cdev->getc = &litex_serial_getc;
cdev->setbrg = NULL;
cdev->linux_console_name = "ttyLXU";
cdev->linux_earlycon_name = "liteuart";
cdev->phys_base = IOMEM(iores->start);
console_register(cdev);
return 0;
}
static __maybe_unused struct of_device_id litex_serial_dt_ids[] = {
{
.compatible = "litex,uart",
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, litex_serial_dt_ids);
static struct driver litex_serial_driver = {
.name = "litex-uart",
.probe = litex_serial_probe,
.of_compatible = DRV_OF_COMPAT(litex_serial_dt_ids),
};
console_platform_driver(litex_serial_driver);
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