ep93xx_amba.c

Cirrus logic ep9302 本机串口驱动程序

#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>

#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/irq.h>

#if defined(CONFIG_SERIAL_AMBA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

#include <asm/hardware/serial_amba.h>

#if !defined(CONFIG_EP93XX_IRDA)
#define UART_NR		3
#else
#define UART_NR		2
#endif

#define SERIAL_AMBA_MAJOR	204
#define SERIAL_AMBA_MINOR	16
#define SERIAL_AMBA_NR		UART_NR

#define CALLOUT_AMBA_NAME	"cuaam"
#define CALLOUT_AMBA_MAJOR	205
#define CALLOUT_AMBA_MINOR	16
#define CALLOUT_AMBA_NR		UART_NR

static struct tty_driver normal, callout;
static struct tty_struct *cs_amba_table[UART_NR];
static struct termios *cs_amba_termios[UART_NR], *cs_amba_termios_locked[UART_NR];
#ifdef SUPPORT_SYSRQ
static struct console cs_amba_console;
#endif

#define AMBA_ISR_PASS_LIMIT	256

/*
 * Access macros for the AMBA UARTs
 */
#define UART_GET_INT_STATUS(p)	((readl((p)->membase + AMBA_UARTIIR)) & 0xff)
#define UART_PUT_ICR(p, c)		writel((c), (p)->membase + AMBA_UARTICR)
#define UART_GET_FR(p)			((readl((p)->membase + AMBA_UARTFR)) & 0xff)
#define UART_GET_CHAR(p)		((readl((p)->membase + AMBA_UARTDR)) & 0xff)
#define UART_PUT_CHAR(p, c)		writel((c), (p)->membase + AMBA_UARTDR)
#define UART_GET_RSR(p)			((readl((p)->membase + AMBA_UARTRSR)) & 0xff)
#define UART_GET_CR(p)			((readl((p)->membase + AMBA_UARTCR)) & 0xff)
#define UART_PUT_CR(p,c)		writel((c), (p)->membase + AMBA_UARTCR)
#define UART_GET_LCRL(p)		((readl((p)->membase + AMBA_UARTLCR_L)) & 0xff)
#define UART_PUT_LCRL(p,c)		writel((c), (p)->membase + AMBA_UARTLCR_L)
#define UART_GET_LCRM(p)		((readl((p)->membase + AMBA_UARTLCR_M)) & 0xff)
#define UART_PUT_LCRM(p,c)		writel((c), (p)->membase + AMBA_UARTLCR_M)
#define UART_GET_LCRH(p)		((readl((p)->membase + AMBA_UARTLCR_H)) & 0xff)
#define UART_PUT_LCRH(p,c)		writel((c), (p)->membase + AMBA_UARTLCR_H)
#define UART_RX_DATA(s)			(((s) & AMBA_UARTFR_RXFE) == 0)
#define UART_TX_READY(s)		(((s) & AMBA_UARTFR_TXFF) == 0)
#define UART_TX_EMPTY(p)		((UART_GET_FR(p) & AMBA_UARTFR_TMSK) == 0)

#define UART_PUT_MCR(c, p)  writel((c), (p)->membase + ((unsigned int)UART1MCR & 0xffff))
#define UART_CLEAR_ECR(p)   writel( 0, (p)->membase + AMBA_UARTECR)

#define UART_DUMMY_RSR_RX	256
#define UART_PORT_SIZE		64

/*
 * Our private driver data mappings.
 */
#define drv_old_status	driver_priv

/*
 * We wrap our port structure around the generic uart_port.
 */
struct uart_amba_port {
	struct uart_port	port;
	unsigned int		dtr_mask;
	unsigned int		rts_mask;
	unsigned int		old_status;
};


static void csambauart_enable_clocks(struct uart_port *port)
{
	unsigned int uiSysDevCfg;

    /*
	 * Enable the clocks to this UART in CSC_syscon
	 * - Read DEVCFG
	 * - OR in the correct uart enable bit
	 * - Set the lock register
	 * - Write back to DEVCFG
	 */
    uiSysDevCfg = inl(SYSCON_DEVCFG);

	switch( port->mapbase ) 
	{
		case UART1_BASE:
		    uiSysDevCfg |= SYSCON_DEVCFG_U1EN;
			break;
	
		case UART2_BASE:
		    uiSysDevCfg |= SYSCON_DEVCFG_U2EN;
			break;

		case UART3_BASE:
		    uiSysDevCfg |= SYSCON_DEVCFG_U3EN;
			break;
	} 
    
	SysconSetLocked( SYSCON_DEVCFG, uiSysDevCfg );
} 

static void csambauart_disable_clocks(struct uart_port *port)
{
	unsigned int uiSysDevCfg;

	/*
	 * Disable the clocks to this UART in CSC_syscon
	 * - Read DEVCFG
	 * - AND to clear the correct uart enable bit
	 * - Set the lock register
	 * - Write back to DEVCFG
	 */
    uiSysDevCfg = inl(SYSCON_DEVCFG);
	
	switch( port->mapbase ) 
	{
		case UART1_BASE:
		    uiSysDevCfg &= ~((unsigned int)SYSCON_DEVCFG_U1EN);
			break;
			
		case UART2_BASE:
		    uiSysDevCfg &= ~((unsigned int)SYSCON_DEVCFG_U2EN);
			break;
			
		case UART3_BASE:
		    uiSysDevCfg &= ~((unsigned int)SYSCON_DEVCFG_U3EN);
			break;
    }
    
	SysconSetLocked( SYSCON_DEVCFG, uiSysDevCfg );
}

static int csambauart_is_port_enabled(struct uart_port *port)
{
	unsigned int uiSysDevCfg;

    uiSysDevCfg = inl(SYSCON_DEVCFG);
	
	switch( port->mapbase ) 
	{
		case UART1_BASE:
		    uiSysDevCfg &= (unsigned int)SYSCON_DEVCFG_U1EN;
			break;
			
		case UART2_BASE:
		    uiSysDevCfg &= (unsigned int)SYSCON_DEVCFG_U2EN;
			break;
			
		case UART3_BASE:
		    uiSysDevCfg &= (unsigned int)SYSCON_DEVCFG_U3EN;
			break;
    }

	return( uiSysDevCfg != 0 );    
}



static void csambauart_stop_tx(struct uart_port *port, unsigned int tty_stop)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr &= ~AMBA_UARTCR_TIE;
	UART_PUT_CR(port, cr);
}

static void csambauart_start_tx(struct uart_port *port, unsigned int tty_start)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr |= AMBA_UARTCR_TIE;
	UART_PUT_CR(port, cr);
}

static void csambauart_stop_rx(struct uart_port *port)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr &= ~(AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE);
	UART_PUT_CR(port, cr);
}

static void csambauart_enable_ms(struct uart_port *port)
{
	unsigned int cr;

	cr = UART_GET_CR(port);
	cr |= AMBA_UARTCR_MSIE;
	UART_PUT_CR(port, cr);
}

static void
#ifdef SUPPORT_SYSRQ
csambauart_rx_chars(struct uart_port *port, struct pt_regs *regs)
#else
csambauart_rx_chars(struct uart_port *port)
#endif
{
	struct tty_struct *tty = port->info->tty;
	unsigned int status, ch, rsr, max_count = 256;

	status = UART_GET_FR(port);
	while (UART_RX_DATA(status) && max_count--) {
		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
			tty->flip.tqueue.routine((void *)tty);
			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
				printk(KERN_WARNING "TTY_DONT_FLIP set\n");
				return;
			}
		}

		ch = UART_GET_CHAR(port);

		*tty->flip.char_buf_ptr = ch;
		*tty->flip.flag_buf_ptr = TTY_NORMAL;
		port->icount.rx++;

		/*
		 * Note that the error handling code is
		 * out of the main execution path
		 */
		rsr = UART_GET_RSR(port) | UART_DUMMY_RSR_RX;
		if (rsr & AMBA_UARTRSR_ANY) {
			if (rsr & AMBA_UARTRSR_BE) {
				rsr &= ~(AMBA_UARTRSR_FE | AMBA_UARTRSR_PE);
				port->icount.brk++;
				if (uart_handle_break(port))
					goto ignore_char;
			} else if (rsr & AMBA_UARTRSR_PE)
				port->icount.parity++;
			else if (rsr & AMBA_UARTRSR_FE)
				port->icount.frame++;
			if (rsr & AMBA_UARTRSR_OE)
				port->icount.overrun++;

			rsr &= port->read_status_mask;

			if (rsr & AMBA_UARTRSR_BE)
				*tty->flip.flag_buf_ptr = TTY_BREAK;
			else if (rsr & AMBA_UARTRSR_PE)
				*tty->flip.flag_buf_ptr = TTY_PARITY;
			else if (rsr & AMBA_UARTRSR_FE)
				*tty->flip.flag_buf_ptr = TTY_FRAME;
		}

		if (uart_handle_sysrq_char(port, ch, regs))
			goto ignore_char;

		if ((rsr & port->ignore_status_mask) == 0) {
			tty->flip.flag_buf_ptr++;
			tty->flip.char_buf_ptr++;
			tty->flip.count++;
		}
		if ((rsr & AMBA_UARTRSR_OE) &&
		    tty->flip.count < TTY_FLIPBUF_SIZE) {
			/*
			 * Overrun is special, since it's reported
			 * immediately, and doesn't affect the current
			 * character
			 */
			*tty->flip.char_buf_ptr++ = 0;
			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;
			tty->flip.count++;
		}
	ignore_char:
		status = UART_GET_FR(port);
	}
	tty_flip_buffer_push(tty);
	return;
}

static void csambauart_tx_chars(struct uart_port *port)
{
	struct circ_buf *xmit = &port->info->xmit;
	int count;

	if (port->x_char) {
		UART_PUT_CHAR(port, port->x_char);
		port->icount.tx++;
		port->x_char = 0;
		return;
	}
	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		csambauart_stop_tx(port, 0);
		return;
	}

	count = port->fifosize >> 1;
	do {
		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	} while (--count > 0);

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	if (uart_circ_empty(xmit))
		csambauart_stop_tx(port, 0);
}

static void csambauart_modem_status(struct uart_port *port)
{
	struct uart_amba_port *uap = (struct uart_amba_port *)port;
	unsigned int status, delta;

	UART_PUT_ICR(&uap->port, 0);

	status = UART_GET_FR(&uap->port) & AMBA_UARTFR_MODEM_ANY;

	delta = status ^ uap->old_status;
	uap->old_status = status;

	if (!delta)
		return;

	if (delta & AMBA_UARTFR_DCD)
		uart_handle_dcd_change(&uap->port, status & AMBA_UARTFR_DCD);

	if (delta & AMBA_UARTFR_DSR)
		uap->port.icount.dsr++;

	if (delta & AMBA_UARTFR_CTS)
		uart_handle_cts_change(&uap->port, status & AMBA_UARTFR_CTS);

	wake_up_interruptible(&uap->port.info->delta_msr_wait);
}

static void csambauart_int(int irq, void *dev_id, struct pt_regs *regs)
{
	struct uart_port *port = dev_id;
	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;

	status = UART_GET_INT_STATUS(port);
	do {
		if (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS))
#ifdef SUPPORT_SYSRQ
			csambauart_rx_chars(port, regs);
#else
			csambauart_rx_chars(port);
#endif
		if (status & AMBA_UARTIIR_TIS)
			csambauart_tx_chars(port);
		if (status & AMBA_UARTIIR_MIS)
			csambauart_modem_status(port);

		if (pass_counter-- == 0)
			break;

		status = UART_GET_INT_STATUS(port);
	} while (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS |
			   AMBA_UARTIIR_TIS));
}

static unsigned int csambauart_tx_empty(struct uart_port *port)
{
	return UART_GET_FR(port) & AMBA_UARTFR_BUSY ? 0 : TIOCSER_TEMT;