137 lines
2.8 KiB
C
137 lines
2.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* RT288x/Au1xxx driver
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*/
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/init.h>
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#include <linux/console.h>
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#include <linux/serial.h>
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#include <linux/serial_8250.h>
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#include "8250.h"
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#define RT288X_DL 0x28
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/* Au1x00/RT288x UART hardware has a weird register layout */
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static const u8 au_io_in_map[7] = {
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[UART_RX] = 0,
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[UART_IER] = 2,
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[UART_IIR] = 3,
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[UART_LCR] = 5,
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[UART_MCR] = 6,
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[UART_LSR] = 7,
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[UART_MSR] = 8,
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};
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static const u8 au_io_out_map[5] = {
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[UART_TX] = 1,
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[UART_IER] = 2,
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[UART_FCR] = 4,
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[UART_LCR] = 5,
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[UART_MCR] = 6,
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};
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static unsigned int au_serial_in(struct uart_port *p, int offset)
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{
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if (offset >= ARRAY_SIZE(au_io_in_map))
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return UINT_MAX;
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offset = au_io_in_map[offset];
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return __raw_readl(p->membase + (offset << p->regshift));
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}
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static void au_serial_out(struct uart_port *p, int offset, int value)
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{
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if (offset >= ARRAY_SIZE(au_io_out_map))
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return;
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offset = au_io_out_map[offset];
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__raw_writel(value, p->membase + (offset << p->regshift));
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}
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/* Au1x00 haven't got a standard divisor latch */
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static u32 au_serial_dl_read(struct uart_8250_port *up)
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{
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return __raw_readl(up->port.membase + RT288X_DL);
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}
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static void au_serial_dl_write(struct uart_8250_port *up, u32 value)
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{
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__raw_writel(value, up->port.membase + RT288X_DL);
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}
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int au_platform_setup(struct plat_serial8250_port *p)
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{
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p->iotype = UPIO_AU;
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p->serial_in = au_serial_in;
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p->serial_out = au_serial_out;
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p->dl_read = au_serial_dl_read;
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p->dl_write = au_serial_dl_write;
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p->mapsize = 0x1000;
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p->bugs |= UART_BUG_NOMSR;
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return 0;
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}
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EXPORT_SYMBOL_GPL(au_platform_setup);
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int rt288x_setup(struct uart_port *p)
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{
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struct uart_8250_port *up = up_to_u8250p(p);
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p->iotype = UPIO_AU;
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p->serial_in = au_serial_in;
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p->serial_out = au_serial_out;
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up->dl_read = au_serial_dl_read;
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up->dl_write = au_serial_dl_write;
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p->mapsize = 0x100;
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up->bugs |= UART_BUG_NOMSR;
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return 0;
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}
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EXPORT_SYMBOL_GPL(rt288x_setup);
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#ifdef CONFIG_SERIAL_8250_CONSOLE
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static void au_putc(struct uart_port *port, unsigned char c)
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{
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unsigned int status;
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au_serial_out(port, UART_TX, c);
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for (;;) {
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status = au_serial_in(port, UART_LSR);
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if (uart_lsr_tx_empty(status))
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break;
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cpu_relax();
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}
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}
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static void au_early_serial8250_write(struct console *console,
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const char *s, unsigned int count)
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{
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struct earlycon_device *device = console->data;
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struct uart_port *port = &device->port;
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uart_console_write(port, s, count, au_putc);
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}
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static int __init early_au_setup(struct earlycon_device *dev, const char *opt)
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{
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rt288x_setup(&dev->port);
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dev->con->write = au_early_serial8250_write;
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return 0;
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}
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OF_EARLYCON_DECLARE(palmchip, "ralink,rt2880-uart", early_au_setup);
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#endif
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MODULE_DESCRIPTION("RT288x/Au1xxx UART driver");
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MODULE_LICENSE("GPL");
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