mpc52xx_uart.c

linux 内核源代码

	if (err && (port->flags & UPF_IOREMAP)) {
		iounmap(port->membase);
		port->membase = NULL;
	}

	return err;
}

static void
mpc52xx_uart_config_port(struct uart_port *port, int flags)
{
	if ( (flags & UART_CONFIG_TYPE) &&
	     (mpc52xx_uart_request_port(port) == 0) )
	     	port->type = PORT_MPC52xx;
}

static int
mpc52xx_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	if ( ser->type != PORT_UNKNOWN && ser->type != PORT_MPC52xx )
		return -EINVAL;

	if ( (ser->irq != port->irq) ||
	     (ser->io_type != SERIAL_IO_MEM) ||
	     (ser->baud_base != port->uartclk)  ||
	     (ser->iomem_base != (void*)port->mapbase) ||
	     (ser->hub6 != 0 ) )
		return -EINVAL;

	return 0;
}


static struct uart_ops mpc52xx_uart_ops = {
	.tx_empty	= mpc52xx_uart_tx_empty,
	.set_mctrl	= mpc52xx_uart_set_mctrl,
	.get_mctrl	= mpc52xx_uart_get_mctrl,
	.stop_tx	= mpc52xx_uart_stop_tx,
	.start_tx	= mpc52xx_uart_start_tx,
	.send_xchar	= mpc52xx_uart_send_xchar,
	.stop_rx	= mpc52xx_uart_stop_rx,
	.enable_ms	= mpc52xx_uart_enable_ms,
	.break_ctl	= mpc52xx_uart_break_ctl,
	.startup	= mpc52xx_uart_startup,
	.shutdown	= mpc52xx_uart_shutdown,
	.set_termios	= mpc52xx_uart_set_termios,
/*	.pm		= mpc52xx_uart_pm,		Not supported yet */
/*	.set_wake	= mpc52xx_uart_set_wake,	Not supported yet */
	.type		= mpc52xx_uart_type,
	.release_port	= mpc52xx_uart_release_port,
	.request_port	= mpc52xx_uart_request_port,
	.config_port	= mpc52xx_uart_config_port,
	.verify_port	= mpc52xx_uart_verify_port
};


/* ======================================================================== */
/* Interrupt handling                                                       */
/* ======================================================================== */

static inline int
mpc52xx_uart_int_rx_chars(struct uart_port *port)
{
	struct tty_struct *tty = port->info->tty;
	unsigned char ch, flag;
	unsigned short status;

	/* While we can read, do so ! */
	while ( (status = in_be16(&PSC(port)->mpc52xx_psc_status)) &
	        MPC52xx_PSC_SR_RXRDY) {

		/* Get the char */
		ch = in_8(&PSC(port)->mpc52xx_psc_buffer_8);

		/* Handle sysreq char */
#ifdef SUPPORT_SYSRQ
		if (uart_handle_sysrq_char(port, ch)) {
			port->sysrq = 0;
			continue;
		}
#endif

		/* Store it */

		flag = TTY_NORMAL;
		port->icount.rx++;

		if ( status & (MPC52xx_PSC_SR_PE |
		               MPC52xx_PSC_SR_FE |
		               MPC52xx_PSC_SR_RB) ) {

			if (status & MPC52xx_PSC_SR_RB) {
				flag = TTY_BREAK;
				uart_handle_break(port);
			} else if (status & MPC52xx_PSC_SR_PE)
				flag = TTY_PARITY;
			else if (status & MPC52xx_PSC_SR_FE)
				flag = TTY_FRAME;

			/* Clear error condition */
			out_8(&PSC(port)->command,MPC52xx_PSC_RST_ERR_STAT);

		}
		tty_insert_flip_char(tty, ch, flag);
		if (status & MPC52xx_PSC_SR_OE) {
			/*
			 * Overrun is special, since it's
			 * reported immediately, and doesn't
			 * affect the current character
			 */
			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
		}
	}

	tty_flip_buffer_push(tty);

	return in_be16(&PSC(port)->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY;
}

static inline int
mpc52xx_uart_int_tx_chars(struct uart_port *port)
{
	struct circ_buf *xmit = &port->info->xmit;

	/* Process out of band chars */
	if (port->x_char) {
		out_8(&PSC(port)->mpc52xx_psc_buffer_8, port->x_char);
		port->icount.tx++;
		port->x_char = 0;
		return 1;
	}

	/* Nothing to do ? */
	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		mpc52xx_uart_stop_tx(port);
		return 0;
	}

	/* Send chars */
	while (in_be16(&PSC(port)->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXRDY) {
		out_8(&PSC(port)->mpc52xx_psc_buffer_8, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	}

	/* Wake up */
	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	/* Maybe we're done after all */
	if (uart_circ_empty(xmit)) {
		mpc52xx_uart_stop_tx(port);
		return 0;
	}

	return 1;
}

static irqreturn_t
mpc52xx_uart_int(int irq, void *dev_id)
{
	struct uart_port *port = dev_id;
	unsigned long pass = ISR_PASS_LIMIT;
	unsigned int keepgoing;
	unsigned short status;

	spin_lock(&port->lock);

	/* While we have stuff to do, we continue */
	do {
		/* If we don't find anything to do, we stop */
		keepgoing = 0;

		/* Read status */
		status = in_be16(&PSC(port)->mpc52xx_psc_isr);
		status &= port->read_status_mask;

		/* Do we need to receive chars ? */
		/* For this RX interrupts must be on and some chars waiting */
		if ( status & MPC52xx_PSC_IMR_RXRDY )
			keepgoing |= mpc52xx_uart_int_rx_chars(port);

		/* Do we need to send chars ? */
		/* For this, TX must be ready and TX interrupt enabled */
		if ( status & MPC52xx_PSC_IMR_TXRDY )
			keepgoing |= mpc52xx_uart_int_tx_chars(port);

		/* Limit number of iteration */
		if ( !(--pass) )
			keepgoing = 0;

	} while (keepgoing);

	spin_unlock(&port->lock);

	return IRQ_HANDLED;
}


/* ======================================================================== */
/* Console ( if applicable )                                                */
/* ======================================================================== */

#ifdef CONFIG_SERIAL_MPC52xx_CONSOLE

static void __init
mpc52xx_console_get_options(struct uart_port *port,
                            int *baud, int *parity, int *bits, int *flow)
{
	struct mpc52xx_psc __iomem *psc = PSC(port);
	unsigned char mr1;

	pr_debug("mpc52xx_console_get_options(port=%p)\n", port);

	/* Read the mode registers */
	out_8(&psc->command,MPC52xx_PSC_SEL_MODE_REG_1);
	mr1 = in_8(&psc->mode);

	/* CT{U,L}R are write-only ! */
	*baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
#if !defined(CONFIG_PPC_MERGE)
	if (__res.bi_baudrate)
		*baud = __res.bi_baudrate;
#endif

	/* Parse them */
	switch (mr1 & MPC52xx_PSC_MODE_BITS_MASK) {
		case MPC52xx_PSC_MODE_5_BITS:	*bits = 5; break;
		case MPC52xx_PSC_MODE_6_BITS:	*bits = 6; break;
		case MPC52xx_PSC_MODE_7_BITS:	*bits = 7; break;
		case MPC52xx_PSC_MODE_8_BITS:
		default:			*bits = 8;
	}

	if (mr1 & MPC52xx_PSC_MODE_PARNONE)
		*parity = 'n';
	else
		*parity = mr1 & MPC52xx_PSC_MODE_PARODD ? 'o' : 'e';
}

static void
mpc52xx_console_write(struct console *co, const char *s, unsigned int count)
{
	struct uart_port *port = &mpc52xx_uart_ports[co->index];
	struct mpc52xx_psc __iomem *psc = PSC(port);
	unsigned int i, j;

	/* Disable interrupts */
	out_be16(&psc->mpc52xx_psc_imr, 0);

	/* Wait the TX buffer to be empty */
	j = 5000000;	/* Maximum wait */
	while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP) &&
	       --j)
		udelay(1);

	/* Write all the chars */
	for (i = 0; i < count; i++, s++) {
		/* Line return handling */
		if (*s == '\n')
			out_8(&psc->mpc52xx_psc_buffer_8, '\r');

		/* Send the char */
		out_8(&psc->mpc52xx_psc_buffer_8, *s);

		/* Wait the TX buffer to be empty */
		j = 20000;	/* Maximum wait */
		while (!(in_be16(&psc->mpc52xx_psc_status) &
		         MPC52xx_PSC_SR_TXEMP) && --j)
			udelay(1);
	}

	/* Restore interrupt state */
	out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
}

#if !defined(CONFIG_PPC_MERGE)
static int __init
mpc52xx_console_setup(struct console *co, char *options)
{
	struct uart_port *port = &mpc52xx_uart_ports[co->index];

	int baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	if (co->index < 0 || co->index >= MPC52xx_PSC_MAXNUM)
		return -EINVAL;

	/* Basic port init. Needed since we use some uart_??? func before
	 * real init for early access */
	spin_lock_init(&port->lock);
	port->uartclk	= __res.bi_ipbfreq / 2; /* Look at CTLR doc */
	port->ops	= &mpc52xx_uart_ops;
	port->mapbase	= MPC52xx_PA(MPC52xx_PSCx_OFFSET(co->index+1));

	/* We ioremap ourself */
	port->membase = ioremap(port->mapbase, MPC52xx_PSC_SIZE);
	if (port->membase == NULL)
		return -EINVAL;

	/* Setup the port parameters accoding to options */
	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);
	else
		mpc52xx_console_get_options(port, &baud, &parity, &bits, &flow);

	return uart_set_options(port, co, baud, parity, bits, flow);
}

#else

static int __init
mpc52xx_console_setup(struct console *co, char *options)
{
	struct uart_port *port = &mpc52xx_uart_ports[co->index];
	struct device_node *np = mpc52xx_uart_nodes[co->index];
	unsigned int ipb_freq;
	struct resource res;
	int ret;

	int baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	pr_debug("mpc52xx_console_setup co=%p, co->index=%i, options=%s\n",
		 co, co->index, options);

	if ((co->index < 0) || (co->index > MPC52xx_PSC_MAXNUM)) {
		pr_debug("PSC%x out of range\n", co->index);
		return -EINVAL;
	}

	if (!np) {
		pr_debug("PSC%x not found in device tree\n", co->index);
		return -EINVAL;
	}

	pr_debug("Console on ttyPSC%x is %s\n",
	         co->index, mpc52xx_uart_nodes[co->index]->full_name);

	/* Fetch register locations */
	if ((ret = of_address_to_resource(np, 0, &res)) != 0) {
		pr_debug("Could not get resources for PSC%x\n", co->index);
		return ret;
	}

	/* Search for bus-frequency property in this node or a parent */
	if ((ipb_freq = mpc52xx_find_ipb_freq(np)) == 0) {
		pr_debug("Could not find IPB bus frequency!\n");
		return -EINVAL;
	}

	/* Basic port init. Needed since we use some uart_??? func before
	 * real init for early access */
	spin_lock_init(&port->lock);
	port->uartclk	= ipb_freq / 2;
	port->ops	= &mpc52xx_uart_ops;
	port->mapbase = res.start;
	port->membase = ioremap(res.start, sizeof(struct mpc52xx_psc));
	port->irq = irq_of_parse_and_map(np, 0);

	if (port->membase == NULL)
		return -EINVAL;

	pr_debug("mpc52xx-psc uart at %p, mapped to %p, irq=%x, freq=%i\n",
	         (void*)port->mapbase, port->membase, port->irq, port->uartclk);

	/* Setup the port parameters accoding to options */
	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);
	else
		mpc52xx_console_get_options(port, &baud, &parity, &bits, &flow);

	pr_debug("Setting console parameters: %i %i%c1 flow=%c\n",
	         baud, bits, parity, flow);

	return uart_set_options(port, co, baud, parity, bits, flow);
}
#endif /* defined(CONFIG_PPC_MERGE) */


static struct uart_driver mpc52xx_uart_driver;