/* * linux/drivers/serial/s3c2410.c * * Driver for onboard UARTs on the Samsung S3C24XX * * Based on drivers/char/serial.c and drivers/char/21285.c * * Ben Dooks, (c) 2003-2005 Simtec Electronics *	http://www.simtec.co.uk/products/SWLINUX/ * * Changelog: * * 22-Jul-2004  BJD  Finished off device rewrite * * 21-Jul-2004  BJD  Thanks to <herbet@13thfloor.at> for pointing out *                   problems with baud rate and loss of IR settings. Update *                   to add configuration via platform_device structure * * 28-Sep-2004  BJD  Re-write for the following items *		     - S3C2410 and S3C2440 serial support *		     - Power Management support *		     - Fix console via IrDA devices *		     - SysReq (Herbert P鰐zl) *		     - Break character handling (Herbert P鰐zl) *		     - spin-lock initialisation (Dimitry Andric) *		     - added clock control *		     - updated init code to use platform_device info * * 06-Mar-2005  BJD  Add s3c2440 fclk clock source * * 09-Mar-2005  BJD  Add s3c2400 support * * 10-Mar-2005  LCVR Changed S3C2410_VA_UART to S3C24XX_VA_UART*//* Note on 2440 fclk clock source handling * * Whilst it is possible to use the fclk as clock source, the method * of properly switching too/from this is currently un-implemented, so * whichever way is configured at startup is the one that will be used.*//* Hote on 2410 error handling * * The s3c2410 manual has a love/hate affair with the contents of the * UERSTAT register in the UART blocks, and keeps marking some of the * error bits as reserved. Having checked with the s3c2410x01, * it copes with BREAKs properly, so I am happy to ignore the RESERVED * feature from the latter versions of the manual. * * If it becomes aparrent that latter versions of the 2410 remove these * bits, then action will have to be taken to differentiate the versions * and change the policy on BREAK * * BJD, 04-Nov-2004*/#include <linux/config.h>#if defined(CONFIG_SERIAL_S3C2410_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)#define SUPPORT_SYSRQ#endif#include <linux/module.h>#include <linux/ioport.h>#include <linux/platform_device.h>#include <linux/init.h>#include <linux/sysrq.h>#include <linux/console.h>#include <linux/tty.h>#include <linux/tty_flip.h>#include <linux/serial_core.h>#include <linux/serial.h>#include <linux/delay.h>#include <linux/clk.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/hardware.h>#include <asm/arch/regs-serial.h>#include <asm/arch/regs-gpio.h>/* structures */struct s3c24xx_uart_info {	char			*name;	unsigned int		type;	unsigned int		fifosize;	unsigned long		rx_fifomask;	unsigned long		rx_fifoshift;	unsigned long		rx_fifofull;	unsigned long		tx_fifomask;	unsigned long		tx_fifoshift;	unsigned long		tx_fifofull;	/* clock source control */	int (*get_clksrc)(struct uart_port *, struct s3c24xx_uart_clksrc *clk);	int (*set_clksrc)(struct uart_port *, struct s3c24xx_uart_clksrc *clk);	/* uart controls */	int (*reset_port)(struct uart_port *, struct s3c2410_uartcfg *);};struct s3c24xx_uart_port {	unsigned char			rx_claimed;	unsigned char			tx_claimed;	struct s3c24xx_uart_info	*info;	struct s3c24xx_uart_clksrc	*clksrc;	struct clk			*clk;	struct clk			*baudclk;	struct uart_port		port;};/* configuration defines */#if 0#if 1/* send debug to the low-level output routines */extern void printascii(const char *);static voids3c24xx_serial_dbg(const char *fmt, ...){	va_list va;	char buff[256];	va_start(va, fmt);	vsprintf(buff, fmt, va);	va_end(va);	printascii(buff);}#define dbg(x...) s3c24xx_serial_dbg(x)#else#define dbg(x...) printk(KERN_DEBUG "s3c24xx: ");#endif#else /* no debug */#define dbg(x...) do {} while(0)#endif/* UART name and device definitions */#define S3C24XX_SERIAL_NAME	"ttySAC"#define S3C24XX_SERIAL_DEVFS    "tts/"#define S3C24XX_SERIAL_MAJOR	204#define S3C24XX_SERIAL_MINOR	64/* conversion functions */#define s3c24xx_dev_to_port(__dev) (struct uart_port *)dev_get_drvdata(__dev)#define s3c24xx_dev_to_cfg(__dev) (struct s3c2410_uartcfg *)((__dev)->platform_data)/* we can support 3 uarts, but not always use them */#ifdef CONFIG_CPU_S3C2400#define NR_PORTS (2)#else#define NR_PORTS (3)#endif/* port irq numbers */#define TX_IRQ(port) ((port)->irq + 1)#define RX_IRQ(port) ((port)->irq)/* register access controls */#define portaddr(port, reg) ((port)->membase + (reg))#define rd_regb(port, reg) (__raw_readb(portaddr(port, reg)))#define rd_regl(port, reg) (__raw_readl(portaddr(port, reg)))#define wr_regb(port, reg, val) \  do { __raw_writeb(val, portaddr(port, reg)); } while(0)#define wr_regl(port, reg, val) \  do { __raw_writel(val, portaddr(port, reg)); } while(0)/* macros to change one thing to another */#define tx_enabled(port) ((port)->unused[0])#define rx_enabled(port) ((port)->unused[1])/* flag to ignore all characters comming in */#define RXSTAT_DUMMY_READ (0x10000000)static inline struct s3c24xx_uart_port *to_ourport(struct uart_port *port){	return container_of(port, struct s3c24xx_uart_port, port);}/* translate a port to the device name */static inline const char *s3c24xx_serial_portname(struct uart_port *port){	return to_platform_device(port->dev)->name;}static int s3c24xx_serial_txempty_nofifo(struct uart_port *port){	return (rd_regl(port, S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXE);}static void s3c24xx_serial_rx_enable(struct uart_port *port){	unsigned long flags;	unsigned int ucon, ufcon;	int count = 10000;	spin_lock_irqsave(&port->lock, flags);	while (--count && !s3c24xx_serial_txempty_nofifo(port))		udelay(100);	ufcon = rd_regl(port, S3C2410_UFCON);	ufcon |= S3C2410_UFCON_RESETRX;	wr_regl(port, S3C2410_UFCON, ufcon);	ucon = rd_regl(port, S3C2410_UCON);	ucon |= S3C2410_UCON_RXIRQMODE;	wr_regl(port, S3C2410_UCON, ucon);	rx_enabled(port) = 1;	spin_unlock_irqrestore(&port->lock, flags);}static void s3c24xx_serial_rx_disable(struct uart_port *port){	unsigned long flags;	unsigned int ucon;	spin_lock_irqsave(&port->lock, flags);	ucon = rd_regl(port, S3C2410_UCON);	ucon &= ~S3C2410_UCON_RXIRQMODE;	wr_regl(port, S3C2410_UCON, ucon);	rx_enabled(port) = 0;	spin_unlock_irqrestore(&port->lock, flags);}static void s3c24xx_serial_stop_tx(struct uart_port *port){	if (tx_enabled(port)) {		disable_irq(TX_IRQ(port));		tx_enabled(port) = 0;		if (port->flags & UPF_CONS_FLOW)			s3c24xx_serial_rx_enable(port);	}}static void s3c24xx_serial_start_tx(struct uart_port *port){	if (!tx_enabled(port)) {		if (port->flags & UPF_CONS_FLOW)			s3c24xx_serial_rx_disable(port);		enable_irq(TX_IRQ(port));		tx_enabled(port) = 1;	}}static void s3c24xx_serial_stop_rx(struct uart_port *port){	if (rx_enabled(port)) {		dbg("s3c24xx_serial_stop_rx: port=%p\n", port);		disable_irq(RX_IRQ(port));		rx_enabled(port) = 0;	}}static void s3c24xx_serial_enable_ms(struct uart_port *port){}static inline struct s3c24xx_uart_info *s3c24xx_port_to_info(struct uart_port *port){	return to_ourport(port)->info;}static inline struct s3c2410_uartcfg *s3c24xx_port_to_cfg(struct uart_port *port){	if (port->dev == NULL)		return NULL;	return (struct s3c2410_uartcfg *)port->dev->platform_data;}static int s3c24xx_serial_rx_fifocnt(struct s3c24xx_uart_port *ourport,				     unsigned long ufstat){	struct s3c24xx_uart_info *info = ourport->info;	if (ufstat & info->rx_fifofull)		return info->fifosize;	return (ufstat & info->rx_fifomask) >> info->rx_fifoshift;}/* ? - where has parity gone?? */#define S3C2410_UERSTAT_PARITY (0x1000)static irqreturn_ts3c24xx_serial_rx_chars(int irq, void *dev_id, struct pt_regs *regs){	struct s3c24xx_uart_port *ourport = dev_id;	struct uart_port *port = &ourport->port;	struct tty_struct *tty = port->info->tty;	unsigned int ufcon, ch, flag, ufstat, uerstat;	int max_count = 64;	while (max_count-- > 0) {		ufcon = rd_regl(port, S3C2410_UFCON);		ufstat = rd_regl(port, S3C2410_UFSTAT);		if (s3c24xx_serial_rx_fifocnt(ourport, ufstat) == 0)			break;		uerstat = rd_regl(port, S3C2410_UERSTAT);		ch = rd_regb(port, S3C2410_URXH);		if (port->flags & UPF_CONS_FLOW) {			int txe = s3c24xx_serial_txempty_nofifo(port);			if (rx_enabled(port)) {				if (!txe) {					rx_enabled(port) = 0;					continue;				}			} else {				if (txe) {					ufcon |= S3C2410_UFCON_RESETRX;					wr_regl(port, S3C2410_UFCON, ufcon);					rx_enabled(port) = 1;					goto out;				}				continue;			}		}		/* insert the character into the buffer */		flag = TTY_NORMAL;		port->icount.rx++;		if (unlikely(uerstat & S3C2410_UERSTAT_ANY)) {			dbg("rxerr: port ch=0x%02x, rxs=0x%08x\n",			    ch, uerstat);			/* check for break */			if (uerstat & S3C2410_UERSTAT_BREAK) {				dbg("break!\n");				port->icount.brk++;				if (uart_handle_break(port))				    goto ignore_char;			}			if (uerstat & S3C2410_UERSTAT_FRAME)				port->icount.frame++;			if (uerstat & S3C2410_UERSTAT_OVERRUN)				port->icount.overrun++;			uerstat &= port->read_status_mask;			if (uerstat & S3C2410_UERSTAT_BREAK)				flag = TTY_BREAK;			else if (uerstat & S3C2410_UERSTAT_PARITY)				flag = TTY_PARITY;			else if (uerstat & ( S3C2410_UERSTAT_FRAME | S3C2410_UERSTAT_OVERRUN))				flag = TTY_FRAME;		}		if (uart_handle_sysrq_char(port, ch, regs))			goto ignore_char;		uart_insert_char(port, uerstat, S3C2410_UERSTAT_OVERRUN, ch, flag);	ignore_char:		continue;	}	tty_flip_buffer_push(tty); out:	return IRQ_HANDLED;}static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id, struct pt_regs *regs){	struct s3c24xx_uart_port *ourport = id;	struct uart_port *port = &ourport->port;	struct circ_buf *xmit = &port->info->xmit;	int count = 256;	if (port->x_char) {		wr_regb(port, S3C2410_UTXH, port->x_char);		port->icount.tx++;		port->x_char = 0;		goto out;	}	/* if there isnt anything more to transmit, or the uart is now	 * stopped, disable the uart and exit	*/	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {		s3c24xx_serial_stop_tx(port);		goto out;	}	/* try and drain the buffer... */	while (!uart_circ_empty(xmit) && count-- > 0) {		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)			break;		wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);		port->icount.tx++;	}	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)		uart_write_wakeup(port);	if (uart_circ_empty(xmit))		s3c24xx_serial_stop_tx(port); out:	return IRQ_HANDLED;}static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port){	struct s3c24xx_uart_info *info = s3c24xx_port_to_info(port);	unsigned long ufstat = rd_regl(port, S3C2410_UFSTAT);	unsigned long ufcon = rd_regl(port, S3C2410_UFCON);	if (ufcon & S3C2410_UFCON_FIFOMODE) {		if ((ufstat & info->tx_fifomask) != 0 ||		    (ufstat & info->tx_fifofull))			return 0;		return 1;	}	return s3c24xx_serial_txempty_nofifo(port);}/* no modem control lines */static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port){	unsigned int umstat = rd_regb(port,S3C2410_UMSTAT);	if (umstat & S3C2410_UMSTAT_CTS)		return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;	else		return TIOCM_CAR | TIOCM_DSR;}static void s3c24xx_serial_set_mctrl(struct uart_port *port, unsigned int mctrl){	/* todo - possibly remove AFC and do manual CTS */}static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state){	unsigned long flags;	unsigned int ucon;	spin_lock_irqsave(&port->lock, flags);	ucon = rd_regl(port, S3C2410_UCON);	if (break_state)		ucon |= S3C2410_UCON_SBREAK;	else		ucon &= ~S3C2410_UCON_SBREAK;	wr_regl(port, S3C2410_UCON, ucon);	spin_unlock_irqrestore(&port->lock, flags);}static void s3c24xx_serial_shutdown(struct uart_port *port){	struct s3c24xx_uart_port *ourport = to_ourport(port);	if (ourport->tx_claimed) {		free_irq(TX_IRQ(port), ourport);		tx_enabled(port) = 0;		ourport->tx_claimed = 0;	}	if (ourport->rx_claimed) {		free_irq(RX_IRQ(port), ourport);		ourport->rx_claimed = 0;		rx_enabled(port) = 0;	}}static int s3c24xx_serial_startup(struct uart_port *port){	struct s3c24xx_uart_port *ourport = to_ourport(port);	int ret;	dbg("s3c24xx_serial_startup: port=%p (%08lx,%p)\n",	    port->mapbase, port->membase);	rx_enabled(port) = 1;	ret = request_irq(RX_IRQ(port),			  s3c24xx_serial_rx_chars, 0,			  s3c24xx_serial_portname(port), ourport);	if (ret != 0) {		printk(KERN_ERR "cannot get irq %d\n", RX_IRQ(port));		return ret;	}	ourport->rx_claimed = 1;	dbg("requesting tx irq...\n");	tx_enabled(port) = 1;	ret = request_irq(TX_IRQ(port),			  s3c24xx_serial_tx_chars, 0,			  s3c24xx_serial_portname(port), ourport);	if (ret) {		printk(KERN_ERR "cannot get irq %d\n", TX_IRQ(port));		goto err;	}	ourport->tx_claimed = 1;	dbg("s3c24xx_serial_startup ok\n");	/* the port reset code should have done the correct	 * register setup for the port controls */	return ret; err:	s3c24xx_serial_shutdown(port);	return ret;}/* power power management control */static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,			      unsigned int old){	struct s3c24xx_uart_port *ourport = to_ourport(port);	switch (level) {	case 3:		if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)			clk_disable(ourport->baudclk);		clk_disable(ourport->clk);		break;	case 0:		clk_enable(ourport->clk);		if (!IS_ERR(ourport->baudclk) && ourport->baudclk != NULL)			clk_enable(ourport->baudclk);		break;	default:		printk(KERN_ERR "s3c24xx_serial: unknown pm %d\n", level);	}}/* baud rate calculation * * The UARTs on the S3C2410/S3C2440 can take their clocks from a number * of different sources, including the peripheral clock ("pclk") and an * external clock ("uclk"). The S3C2440 also adds the core clock ("fclk") * with a programmable extra divisor. * * The following code goes through the clock sources, and calculates the * baud clocks (and the resultant actual baud rates) and then tries to * pick the closest one and select that. **/#define MAX_CLKS (8)