mpc52xx_uart.c

Linux Kernel 2.6.9 for OMAP1710

				/*
				 * Overrun is special, since it's
				 * reported immediately, and doesn't
				 * affect the current character
				 */
				if (tty->flip.count < (TTY_FLIPBUF_SIZE-1)) {
					tty->flip.flag_buf_ptr++;
					tty->flip.char_buf_ptr++;
					tty->flip.count++;
				}
				*tty->flip.flag_buf_ptr = TTY_OVERRUN;
			}

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

		}

		tty->flip.char_buf_ptr++;
		tty->flip.flag_buf_ptr++;
		tty->flip.count++;

	}

	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,0);
		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,0);
		return 0;
	}

	return 1;
}

static irqreturn_t 
mpc52xx_uart_int(int irq, void *dev_id, struct pt_regs *regs)
{
	struct uart_port *port = (struct uart_port *) dev_id;
	unsigned long pass = ISR_PASS_LIMIT;
	unsigned int keepgoing;
	unsigned short status;
	
	if ( irq != port->irq ) {
		printk( KERN_WARNING
		        "mpc52xx_uart_int : " \
		        "Received wrong int %d. Waiting for %d\n",
		       irq, port->irq);
		return IRQ_NONE;
	}
	
	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, regs);

		/* 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 *psc = PSC(port);
	unsigned char mr1;

	/* 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 = __res.bi_baudrate ?
		__res.bi_baudrate : CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;

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

		/* Line return handling */
		if ( *s++ == '\n' )
			out_8(&psc->mpc52xx_psc_buffer_8, '\r');
		
		/* 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);
}

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

	int baud = 9600;
	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 */
	port->lock	= SPIN_LOCK_UNLOCKED;
	port->uartclk	= __res.bi_ipbfreq / 2; /* Look at CTLR doc */
	port->ops	= &mpc52xx_uart_ops;
	port->mapbase	= MPC52xx_PSCx(co->index);

		/* We ioremap ourself */
	port->membase = ioremap(port->mapbase, sizeof(struct mpc52xx_psc));
	if (port->membase == NULL) {
		release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));
		return -EBUSY;
	}

	/* 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);
}


extern struct uart_driver mpc52xx_uart_driver;

static struct console mpc52xx_console = {
	.name	= "ttyS",
	.write	= mpc52xx_console_write,
	.device	= uart_console_device,
	.setup	= mpc52xx_console_setup,
	.flags	= CON_PRINTBUFFER,
	.index	= -1,	/* Specified on the cmdline (e.g. console=ttyS0 ) */
	.data	= &mpc52xx_uart_driver,
};

	
static int __init 
mpc52xx_console_init(void)
{
	register_console(&mpc52xx_console);
	return 0;
}

console_initcall(mpc52xx_console_init);

#define MPC52xx_PSC_CONSOLE &mpc52xx_console
#else
#define MPC52xx_PSC_CONSOLE NULL
#endif


/* ======================================================================== */
/* UART Driver                                                              */
/* ======================================================================== */

static struct uart_driver mpc52xx_uart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "mpc52xx_psc_uart",
	.dev_name	= "ttyS",
	.devfs_name	= "ttyS",
	.major		= TTY_MAJOR,
	.minor		= 64,
	.nr		= MPC52xx_PSC_MAXNUM,
	.cons		= MPC52xx_PSC_CONSOLE,
};


/* ======================================================================== */
/* OCP Driver                                                               */
/* ======================================================================== */

static int __devinit
mpc52xx_uart_probe(struct ocp_device *ocp)
{
	struct uart_port *port = NULL;
	int idx, ret;

	/* Get the corresponding port struct */
	idx = ocp->def->index;
	if (idx < 0 || idx >= MPC52xx_PSC_MAXNUM)
		return -EINVAL;
	
	port = &mpc52xx_uart_ports[idx];

	/* Init the port structure */
	port->lock	= SPIN_LOCK_UNLOCKED;
	port->mapbase	= ocp->def->paddr;
	port->irq	= ocp->def->irq;
	port->uartclk	= __res.bi_ipbfreq / 2; /* Look at CTLR doc */
	port->fifosize	= 255; /* Should be 512 ! But it can't be */
	                       /* stored in a unsigned char       */
	port->iotype	= UPIO_MEM;
	port->flags	= UPF_BOOT_AUTOCONF |
			  ( uart_console(port) ? 0 : UPF_IOREMAP );
	port->line	= idx;
	port->ops	= &mpc52xx_uart_ops;
	port->read_status_mask = 0;
	
	/* Requests the mem & irqs */
	/* Unlike other serial drivers, we reserve the resources here, so we
	 * can detect early if multiple drivers uses the same PSC. Special
	 * care must be taken with the console PSC
	 */
	ret = request_irq(
		port->irq, mpc52xx_uart_int,
		SA_INTERRUPT | SA_SAMPLE_RANDOM, "mpc52xx_psc_uart", port);
	if (ret)
		goto error;

	ret = request_mem_region(port->mapbase, sizeof(struct mpc52xx_psc),
	                         "mpc52xx_psc_uart") != NULL ? 0 : -EBUSY;
	if (ret)
		goto free_irq;

	/* Add the port to the uart sub-system */
	ret = uart_add_one_port(&mpc52xx_uart_driver, port);
	if (ret)
		goto release_mem;

	ocp_set_drvdata(ocp, (void*)port);

	return 0;


free_irq:
	free_irq(port->irq, mpc52xx_uart_int);

release_mem:
	release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));

error:
	if (uart_console(port))
		printk(	"mpc52xx_uart.c: Error during resource alloction for "
			"the console port !!! Check that the console PSC is "
			"not used by another OCP driver !!!\n" );

	return ret;
}

static void
mpc52xx_uart_remove(struct ocp_device *ocp)
{
	struct uart_port *port = (struct uart_port *) ocp_get_drvdata(ocp);

	ocp_set_drvdata(ocp, NULL);

	if (port) {
		uart_remove_one_port(&mpc52xx_uart_driver, port);
		release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));
		free_irq(port->irq, mpc52xx_uart_int);
	}
}

#ifdef CONFIG_PM
static int
mpc52xx_uart_suspend(struct ocp_device *ocp, u32 state)
{
	struct uart_port *port = (struct uart_port *) ocp_get_drvdata(ocp);

	uart_suspend_port(&mpc52xx_uart_driver, port);

	return 0;
}

static int
mpc52xx_uart_resume(struct ocp_device *ocp)
{
	struct uart_port *port = (struct uart_port *) ocp_get_drvdata(ocp);

	uart_resume_port(&mpc52xx_uart_driver, port);

	return 0;
}
#endif

static struct ocp_device_id mpc52xx_uart_ids[] __devinitdata = {
	{ .vendor = OCP_VENDOR_FREESCALE, .function = OCP_FUNC_PSC_UART },
	{ .vendor = OCP_VENDOR_INVALID /* Terminating entry */ }
};

MODULE_DEVICE_TABLE(ocp, mpc52xx_uart_ids);

static struct ocp_driver mpc52xx_uart_ocp_driver = {
	.name		= "mpc52xx_psc_uart",
	.id_table	= mpc52xx_uart_ids,
	.probe		= mpc52xx_uart_probe,
	.remove		= mpc52xx_uart_remove,
#ifdef CONFIG_PM
	.suspend	= mpc52xx_uart_suspend,
	.resume		= mpc52xx_uart_resume,
#endif
};


/* ======================================================================== */
/* Module                                                                   */
/* ======================================================================== */

static int __init
mpc52xx_uart_init(void)
{
	int ret;

	printk(KERN_INFO "Serial: MPC52xx PSC driver\n");

	ret = uart_register_driver(&mpc52xx_uart_driver);
	if (ret)
		return ret;

	ret = ocp_register_driver(&mpc52xx_uart_ocp_driver);

	return ret;
}

static void __exit
mpc52xx_uart_exit(void)
{
	ocp_unregister_driver(&mpc52xx_uart_ocp_driver);
	uart_unregister_driver(&mpc52xx_uart_driver);
}


module_init(mpc52xx_uart_init);
module_exit(mpc52xx_uart_exit);

MODULE_AUTHOR("Sylvain Munaut <[e-mail]>");
MODULE_DESCRIPTION("Freescale MPC52xx PSC UART");
MODULE_LICENSE("GPL");