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    /*
     * (c) 2004 Sascha Hauer <sascha@saschahauer.de>
     *
     * This program is free software; you can redistribute it and/or modify
     * it under the terms of the GNU General Public License as published by
     * the Free Software Foundation; either version 2 of the License, or
     * (at your option) any later version.
     *
     * This program is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     * GNU General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
     *
     */
    
    #include <common.h>
    #include <asm/arch/imx-regs.h>
    
    #if defined CONFIG_IMX_SERIAL1
    #define UART_BASE IMX_UART1_BASE
    #elif defined CONFIG_IMX_SERIAL2
    #define UART_BASE IMX_UART2_BASE
    #else
    #error "define CONFIG_IMX_SERIAL1, CONFIG_IMX_SERIAL2 or CONFIG_IMX_SERIAL_NONE"
    #endif
    
    struct imx_serial {
    	volatile uint32_t urxd[16];
    	volatile uint32_t utxd[16];
    	volatile uint32_t ucr1;
    	volatile uint32_t ucr2;
    	volatile uint32_t ucr3;
    	volatile uint32_t ucr4;
    	volatile uint32_t ufcr;
    	volatile uint32_t usr1;
    	volatile uint32_t usr2;
    	volatile uint32_t uesc;
    	volatile uint32_t utim;
    	volatile uint32_t ubir;
    	volatile uint32_t ubmr;
    	volatile uint32_t ubrc;
    	volatile uint32_t bipr[4];
    	volatile uint32_t bmpr[4];
    	volatile uint32_t uts;
    };
    
    
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    void serial_setbrg (void)
    {
    	serial_init();
    }
    
    extern void imx_gpio_mode(int gpio_mode);
    
    /*
     * Initialise the serial port with the given baudrate. The settings
     * are always 8 data bits, no parity, 1 stop bit, no start bits.
     *
     */
    int serial_init (void)
    {
    	volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
    
    	unsigned int ufcr_rfdiv;
    	unsigned int refclk;
    
    
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    #ifdef CONFIG_IMX_SERIAL1
    	imx_gpio_mode(PC11_PF_UART1_TXD);
    	imx_gpio_mode(PC12_PF_UART1_RXD);
    #else
    	imx_gpio_mode(PB30_PF_UART2_TXD);
    	imx_gpio_mode(PB31_PF_UART2_RXD);
    #endif
    
    	/* Disable UART */
    	base->ucr1 &= ~UCR1_UARTEN;
    
    	/* Set to default POR state */
    
    	base->ucr1 = 0x00000004;
    	base->ucr2 = 0x00000000;
    	base->ucr3 = 0x00000000;
    	base->ucr4 = 0x00008040;
    	base->uesc = 0x0000002B;
    	base->utim = 0x00000000;
    	base->ubir = 0x00000000;
    	base->ubmr = 0x00000000;
    	base->uts  = 0x00000000;
    	/* Set clocks */
    	base->ucr4 |= UCR4_REF16;
    
    	/* Configure FIFOs */
    	base->ufcr = 0xa81;
    
    
    	/* set the baud rate.
    	 *
    	 * baud * 16   x
    	 * --------- = -
    	 *  refclk     y
    	 *
    	 * x - 1 = UBIR
    	 * y - 1 = UBMR
    	 *
    	 * each register is 16 bits wide. refclk max is 96 MHz
    	 *
    	 */
    
    	ufcr_rfdiv = ((base->ufcr) & UFCR_RFDIV) >> 7;
    	if (ufcr_rfdiv == 6)
    		ufcr_rfdiv = 7;
    	else
    		ufcr_rfdiv = 6 - ufcr_rfdiv;
    
    	refclk = get_PERCLK1();
    	refclk /= ufcr_rfdiv;
    
    
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    	/* Set the numerator value minus one of the BRM ratio */
    
    	base->ubir = (gd->baudrate / 100) - 1;
    
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    	/* Set the denominator value minus one of the BRM ratio	*/
    
    	base->ubmr = (refclk/(16 * 100)) - 1;
    
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    	/* Set to 8N1 */
    	base->ucr2 &= ~UCR2_PREN;
    	base->ucr2 |= UCR2_WS;
    	base->ucr2 &= ~UCR2_STPB;
    
    	/* Ignore RTS */
    	base->ucr2 |= UCR2_IRTS;
    
    	/* Enable UART */
    	base->ucr1 |= UCR1_UARTEN | UCR1_UARTCLKEN;
    
    	/* Enable FIFOs */
    	base->ucr2 |= UCR2_SRST | UCR2_RXEN | UCR2_TXEN;
    
    
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    	/* Clear status flags */
    
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    	base->usr2 |= USR2_ADET  |
    
    		      USR2_DTRF  |
    		      USR2_IDLE  |
    		      USR2_IRINT |
    		      USR2_WAKE  |
    		      USR2_RTSF  |
    		      USR2_BRCD  |
    		      USR2_ORE;
    
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    	/* Clear status flags */
    
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    	base->usr1 |= USR1_PARITYERR |
    
    		      USR1_RTSD      |
    		      USR1_ESCF      |
    		      USR1_FRAMERR   |
    		      USR1_AIRINT    |
    		      USR1_AWAKE;
    
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    	return (0);
    }
    
    /*
     * Read a single byte from the serial port. Returns 1 on success, 0
     * otherwise. When the function is successful, the character read is
     * written into its argument c.
     */
    int serial_getc (void)
    {
    	volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
    	unsigned char ch;
    
    	while(base->uts & UTS_RXEMPTY);
    
    	ch = (char)base->urxd[0];
    
    	return ch;
    }
    
    #ifdef CONFIG_HWFLOW
    static int hwflow = 0; /* turned off by default */
    int hwflow_onoff(int on)
    {
    }
    #endif
    
    /*
     * Output a single byte to the serial port.
     */
    void serial_putc (const char c)
    {
    	volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
    
    	/* Wait for Tx FIFO not full */
    	while (base->uts & UTS_TXFULL);
    
    	base->utxd[0] = c;
    
    	/* If \n, also do \r */
    	if (c == '\n')
    		serial_putc ('\r');
    }
    
    /*
     * Test whether a character is in the RX buffer
     */
    int serial_tstc (void)
    {
    	volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
    
    	/* If receive fifo is empty, return false */
    	if (base->uts & UTS_RXEMPTY)
    		return 0;
    	return 1;
    }
    
    void
    serial_puts (const char *s)
    {
    	while (*s) {
    		serial_putc (*s++);
    	}
    }