amba-pl011.c

linux 内核源代码

static void
pl011_set_termios(struct uart_port *port, struct ktermios *termios,
		     struct ktermios *old)
{
	unsigned int lcr_h, old_cr;
	unsigned long flags;
	unsigned int baud, quot;

	/*
	 * Ask the core to calculate the divisor for us.
	 */
	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
	quot = port->uartclk * 4 / baud;

	switch (termios->c_cflag & CSIZE) {
	case CS5:
		lcr_h = UART01x_LCRH_WLEN_5;
		break;
	case CS6:
		lcr_h = UART01x_LCRH_WLEN_6;
		break;
	case CS7:
		lcr_h = UART01x_LCRH_WLEN_7;
		break;
	default: // CS8
		lcr_h = UART01x_LCRH_WLEN_8;
		break;
	}
	if (termios->c_cflag & CSTOPB)
		lcr_h |= UART01x_LCRH_STP2;
	if (termios->c_cflag & PARENB) {
		lcr_h |= UART01x_LCRH_PEN;
		if (!(termios->c_cflag & PARODD))
			lcr_h |= UART01x_LCRH_EPS;
	}
	if (port->fifosize > 1)
		lcr_h |= UART01x_LCRH_FEN;

	spin_lock_irqsave(&port->lock, flags);

	/*
	 * Update the per-port timeout.
	 */
	uart_update_timeout(port, termios->c_cflag, baud);

	port->read_status_mask = UART011_DR_OE | 255;
	if (termios->c_iflag & INPCK)
		port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
	if (termios->c_iflag & (BRKINT | PARMRK))
		port->read_status_mask |= UART011_DR_BE;

	/*
	 * Characters to ignore
	 */
	port->ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
	if (termios->c_iflag & IGNBRK) {
		port->ignore_status_mask |= UART011_DR_BE;
		/*
		 * If we're ignoring parity and break indicators,
		 * ignore overruns too (for real raw support).
		 */
		if (termios->c_iflag & IGNPAR)
			port->ignore_status_mask |= UART011_DR_OE;
	}

	/*
	 * Ignore all characters if CREAD is not set.
	 */
	if ((termios->c_cflag & CREAD) == 0)
		port->ignore_status_mask |= UART_DUMMY_DR_RX;

	if (UART_ENABLE_MS(port, termios->c_cflag))
		pl011_enable_ms(port);

	/* first, disable everything */
	old_cr = readw(port->membase + UART011_CR);
	writew(0, port->membase + UART011_CR);

	/* Set baud rate */
	writew(quot & 0x3f, port->membase + UART011_FBRD);
	writew(quot >> 6, port->membase + UART011_IBRD);

	/*
	 * ----------v----------v----------v----------v-----
	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
	 * ----------^----------^----------^----------^-----
	 */
	writew(lcr_h, port->membase + UART011_LCRH);
	writew(old_cr, port->membase + UART011_CR);

	spin_unlock_irqrestore(&port->lock, flags);
}

static const char *pl011_type(struct uart_port *port)
{
	return port->type == PORT_AMBA ? "AMBA/PL011" : NULL;
}

/*
 * Release the memory region(s) being used by 'port'
 */
static void pl010_release_port(struct uart_port *port)
{
	release_mem_region(port->mapbase, SZ_4K);
}

/*
 * Request the memory region(s) being used by 'port'
 */
static int pl010_request_port(struct uart_port *port)
{
	return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
			!= NULL ? 0 : -EBUSY;
}

/*
 * Configure/autoconfigure the port.
 */
static void pl010_config_port(struct uart_port *port, int flags)
{
	if (flags & UART_CONFIG_TYPE) {
		port->type = PORT_AMBA;
		pl010_request_port(port);
	}
}

/*
 * verify the new serial_struct (for TIOCSSERIAL).
 */
static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	int ret = 0;
	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
		ret = -EINVAL;
	if (ser->irq < 0 || ser->irq >= NR_IRQS)
		ret = -EINVAL;
	if (ser->baud_base < 9600)
		ret = -EINVAL;
	return ret;
}

static struct uart_ops amba_pl011_pops = {
	.tx_empty	= pl01x_tx_empty,
	.set_mctrl	= pl011_set_mctrl,
	.get_mctrl	= pl01x_get_mctrl,
	.stop_tx	= pl011_stop_tx,
	.start_tx	= pl011_start_tx,
	.stop_rx	= pl011_stop_rx,
	.enable_ms	= pl011_enable_ms,
	.break_ctl	= pl011_break_ctl,
	.startup	= pl011_startup,
	.shutdown	= pl011_shutdown,
	.set_termios	= pl011_set_termios,
	.type		= pl011_type,
	.release_port	= pl010_release_port,
	.request_port	= pl010_request_port,
	.config_port	= pl010_config_port,
	.verify_port	= pl010_verify_port,
};

static struct uart_amba_port *amba_ports[UART_NR];

#ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE

static void pl011_console_putchar(struct uart_port *port, int ch)
{
	struct uart_amba_port *uap = (struct uart_amba_port *)port;

	while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
		barrier();
	writew(ch, uap->port.membase + UART01x_DR);
}

static void
pl011_console_write(struct console *co, const char *s, unsigned int count)
{
	struct uart_amba_port *uap = amba_ports[co->index];
	unsigned int status, old_cr, new_cr;

	clk_enable(uap->clk);

	/*
	 *	First save the CR then disable the interrupts
	 */
	old_cr = readw(uap->port.membase + UART011_CR);
	new_cr = old_cr & ~UART011_CR_CTSEN;
	new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
	writew(new_cr, uap->port.membase + UART011_CR);

	uart_console_write(&uap->port, s, count, pl011_console_putchar);

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the TCR
	 */
	do {
		status = readw(uap->port.membase + UART01x_FR);
	} while (status & UART01x_FR_BUSY);
	writew(old_cr, uap->port.membase + UART011_CR);

	clk_disable(uap->clk);
}

static void __init
pl011_console_get_options(struct uart_amba_port *uap, int *baud,
			     int *parity, int *bits)
{
	if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
		unsigned int lcr_h, ibrd, fbrd;

		lcr_h = readw(uap->port.membase + UART011_LCRH);

		*parity = 'n';
		if (lcr_h & UART01x_LCRH_PEN) {
			if (lcr_h & UART01x_LCRH_EPS)
				*parity = 'e';
			else
				*parity = 'o';
		}

		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
			*bits = 7;
		else
			*bits = 8;

		ibrd = readw(uap->port.membase + UART011_IBRD);
		fbrd = readw(uap->port.membase + UART011_FBRD);

		*baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
	}
}

static int __init pl011_console_setup(struct console *co, char *options)
{
	struct uart_amba_port *uap;
	int baud = 38400;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	/*
	 * Check whether an invalid uart number has been specified, and
	 * if so, search for the first available port that does have
	 * console support.
	 */
	if (co->index >= UART_NR)
		co->index = 0;
	uap = amba_ports[co->index];
	if (!uap)
		return -ENODEV;

	uap->port.uartclk = clk_get_rate(uap->clk);

	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);
	else
		pl011_console_get_options(uap, &baud, &parity, &bits);

	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
}

static struct uart_driver amba_reg;
static struct console amba_console = {
	.name		= "ttyAMA",
	.write		= pl011_console_write,
	.device		= uart_console_device,
	.setup		= pl011_console_setup,
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
	.data		= &amba_reg,
};

#define AMBA_CONSOLE	(&amba_console)
#else
#define AMBA_CONSOLE	NULL
#endif

static struct uart_driver amba_reg = {
	.owner			= THIS_MODULE,
	.driver_name		= "ttyAMA",
	.dev_name		= "ttyAMA",
	.major			= SERIAL_AMBA_MAJOR,
	.minor			= SERIAL_AMBA_MINOR,
	.nr			= UART_NR,
	.cons			= AMBA_CONSOLE,
};

static int pl011_probe(struct amba_device *dev, void *id)
{
	struct uart_amba_port *uap;
	void __iomem *base;
	int i, ret;

	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
		if (amba_ports[i] == NULL)
			break;

	if (i == ARRAY_SIZE(amba_ports)) {
		ret = -EBUSY;
		goto out;
	}

	uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
	if (uap == NULL) {
		ret = -ENOMEM;
		goto out;
	}

	base = ioremap(dev->res.start, PAGE_SIZE);
	if (!base) {
		ret = -ENOMEM;
		goto free;
	}

	uap->clk = clk_get(&dev->dev, "UARTCLK");
	if (IS_ERR(uap->clk)) {
		ret = PTR_ERR(uap->clk);
		goto unmap;
	}

	uap->port.dev = &dev->dev;
	uap->port.mapbase = dev->res.start;
	uap->port.membase = base;
	uap->port.iotype = UPIO_MEM;
	uap->port.irq = dev->irq[0];
	uap->port.fifosize = 16;
	uap->port.ops = &amba_pl011_pops;
	uap->port.flags = UPF_BOOT_AUTOCONF;
	uap->port.line = i;

	amba_ports[i] = uap;

	amba_set_drvdata(dev, uap);
	ret = uart_add_one_port(&amba_reg, &uap->port);
	if (ret) {
		amba_set_drvdata(dev, NULL);
		amba_ports[i] = NULL;
		clk_put(uap->clk);
 unmap:
		iounmap(base);
 free:
		kfree(uap);
	}
 out:
	return ret;
}

static int pl011_remove(struct amba_device *dev)
{
	struct uart_amba_port *uap = amba_get_drvdata(dev);
	int i;

	amba_set_drvdata(dev, NULL);

	uart_remove_one_port(&amba_reg, &uap->port);

	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
		if (amba_ports[i] == uap)
			amba_ports[i] = NULL;

	iounmap(uap->port.membase);
	clk_put(uap->clk);
	kfree(uap);
	return 0;
}

static struct amba_id pl011_ids[] __initdata = {
	{
		.id	= 0x00041011,
		.mask	= 0x000fffff,
	},
	{ 0, 0 },
};

static struct amba_driver pl011_driver = {
	.drv = {
		.name	= "uart-pl011",
	},
	.id_table	= pl011_ids,
	.probe		= pl011_probe,
	.remove		= pl011_remove,
};

static int __init pl011_init(void)
{
	int ret;
	printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");

	ret = uart_register_driver(&amba_reg);
	if (ret == 0) {
		ret = amba_driver_register(&pl011_driver);
		if (ret)
			uart_unregister_driver(&amba_reg);
	}
	return ret;
}

static void __exit pl011_exit(void)
{
	amba_driver_unregister(&pl011_driver);
	uart_unregister_driver(&amba_reg);
}

module_init(pl011_init);
module_exit(pl011_exit);

MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("ARM AMBA serial port driver");
MODULE_LICENSE("GPL");