cpu/mips/ar7240/ar7240_serial.c

/*
 * Copyright (c) 2013 Qualcomm Atheros, Inc.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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 <asm/addrspace.h>
#include <asm/types.h>
#include <config.h>
#include <ar7240_soc.h>

#define		REG_OFFSET		4

/* === END OF CONFIG === */

/* register offset */
#define         OFS_RCV_BUFFER          (0*REG_OFFSET)
#define         OFS_TRANS_HOLD          (0*REG_OFFSET)
#define         OFS_SEND_BUFFER         (0*REG_OFFSET)
#define         OFS_INTR_ENABLE         (1*REG_OFFSET)
#define         OFS_INTR_ID             (2*REG_OFFSET)
#define         OFS_DATA_FORMAT         (3*REG_OFFSET)
#define         OFS_LINE_CONTROL        (3*REG_OFFSET)
#define         OFS_MODEM_CONTROL       (4*REG_OFFSET)
#define         OFS_RS232_OUTPUT        (4*REG_OFFSET)
#define         OFS_LINE_STATUS         (5*REG_OFFSET)
#define         OFS_MODEM_STATUS        (6*REG_OFFSET)
#define         OFS_RS232_INPUT         (6*REG_OFFSET)
#define         OFS_SCRATCH_PAD         (7*REG_OFFSET)

#define         OFS_DIVISOR_LSB         (0*REG_OFFSET)
#define         OFS_DIVISOR_MSB         (1*REG_OFFSET)

#define         MY_WRITE(y, z)  ((*((volatile u32*)(y))) = z)
#define         UART16550_READ(y)   ar7240_reg_rd((AR7240_UART_BASE+y))
#define         UART16550_WRITE(x, z)  ar7240_reg_wr((AR7240_UART_BASE+x), z)

void
ar7240_sys_frequency(u32 *cpu_freq, u32 *ddr_freq, u32 *ahb_freq)
{
    u32 pll, pll_div, ref_div, ahb_div, ddr_div, freq;

    pll = ar7240_reg_rd(AR7240_CPU_PLL_CONFIG);

    pll_div =
        ((pll & PLL_CONFIG_PLL_DIV_MASK) >> PLL_CONFIG_PLL_DIV_SHIFT);

    ref_div =
        ((pll & PLL_CONFIG_PLL_REF_DIV_MASK) >> PLL_CONFIG_PLL_REF_DIV_SHIFT);

    ddr_div =
        ((pll & PLL_CONFIG_DDR_DIV_MASK) >> PLL_CONFIG_DDR_DIV_SHIFT) + 1;

    ahb_div =
       (((pll & PLL_CONFIG_AHB_DIV_MASK) >> PLL_CONFIG_AHB_DIV_SHIFT) + 1)*2;

    freq = pll_div * ref_div * 5000000;

    if (cpu_freq)
        *cpu_freq = freq;

    if (ddr_freq)
        *ddr_freq = freq/ddr_div;

    if (ahb_freq)
        *ahb_freq = freq/ahb_div;
}

int serial_init(void)
{
    u32 div,val;
    u32 ahb_freq, ddr_freq, cpu_freq;

#ifdef CONFIG_WASP
    val = ar7240_reg_rd(WASP_BOOTSTRAP_REG);

    if ((val & WASP_REF_CLK_25) == 0) {
        div = (25 * 1000000) / (16 * CONFIG_BAUDRATE);
    } else {
        div = (40 * 1000000) / (16 * CONFIG_BAUDRATE);
    }
#else

    ar7240_sys_frequency(&cpu_freq, &ddr_freq, &ahb_freq);

    div  = ahb_freq/(16 * CONFIG_BAUDRATE);

    MY_WRITE(0xb8040000, 0xcff);
    MY_WRITE(0xb8040008, 0x3b);

    val = ar7240_reg_rd(0xb8040028);
    MY_WRITE(0xb8040028,(val | 0x8002));

    MY_WRITE(0xb8040008, 0x2f);
#endif

    /*
     * set DIAB bit
     */
    UART16550_WRITE(OFS_LINE_CONTROL, 0x80);

    /* set divisor */
    UART16550_WRITE(OFS_DIVISOR_LSB, (div & 0xff));
    UART16550_WRITE(OFS_DIVISOR_MSB, ((div >> 8) & 0xff));

    /* clear DIAB bit*/
    UART16550_WRITE(OFS_LINE_CONTROL, 0x00);

    /* set data format */
    UART16550_WRITE(OFS_DATA_FORMAT, 0x3);

    UART16550_WRITE(OFS_INTR_ENABLE, 0);

    return 0;
}

int serial_tstc (void)
{
    return(UART16550_READ(OFS_LINE_STATUS) & 0x1);
}

u8 serial_getc(void)
{
    while(!serial_tstc());

    return UART16550_READ(OFS_RCV_BUFFER);
}


void serial_putc(u8 byte)
{
    if (byte == '\n') serial_putc ('\r');

    while (((UART16550_READ(OFS_LINE_STATUS)) & 0x20) == 0x0);
    UART16550_WRITE(OFS_SEND_BUFFER, byte);
}

void serial_setbrg (void)
{
}

void serial_puts (const char *s)
{
	while (*s)
	{
		serial_putc (*s++);
	}
}