serial.c

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/*
 * arch/arm/mach-lpc32xx/serial.c
 *
 * Author: Kevin Wells <[email protected]>
 *
 * Copyright (C) 2010 NXP Semiconductors
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/serial_8250.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <mach/platform.h>
#include "common.h"

#define LPC32XX_SUART_FIFO_SIZE 64

struct uartinit {
    char *uart_ck_name;
    u32 ck_mode_mask;
    void __iomem *pdiv_clk_reg;
    resource_size_t mapbase;
};

static struct uartinit uartinit_data[] __initdata = {
    {
        .uart_ck_name = "uart5_ck",
        .ck_mode_mask =
            LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 5),
        .pdiv_clk_reg = LPC32XX_CLKPWR_UART5_CLK_CTRL,
        .mapbase = LPC32XX_UART5_BASE,
    },
    {
        .uart_ck_name = "uart3_ck",
        .ck_mode_mask =
            LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 3),
        .pdiv_clk_reg = LPC32XX_CLKPWR_UART3_CLK_CTRL,
        .mapbase = LPC32XX_UART3_BASE,
    },
    {
        .uart_ck_name = "uart4_ck",
        .ck_mode_mask =
            LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 4),
        .pdiv_clk_reg = LPC32XX_CLKPWR_UART4_CLK_CTRL,
        .mapbase = LPC32XX_UART4_BASE,
    },
    {
        .uart_ck_name = "uart6_ck",
        .ck_mode_mask =
            LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 6),
        .pdiv_clk_reg = LPC32XX_CLKPWR_UART6_CLK_CTRL,
        .mapbase = LPC32XX_UART6_BASE,
    },
};

void __init lpc32xx_serial_init(void)
{
    u32 tmp, clkmodes = 0;
    struct clk *clk;
    unsigned int puart;
    int i, j;

    /* UART clocks are off, let clock driver manage them */
    __raw_writel(0, LPC32XX_CLKPWR_UART_CLK_CTRL);

    for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
        clk = clk_get(NULL, uartinit_data[i].uart_ck_name);
        if (!IS_ERR(clk)) {
            clk_enable(clk);
        }

        /* Setup UART clock modes for all UARTs, disable autoclock */
        clkmodes |= uartinit_data[i].ck_mode_mask;

        /* pre-UART clock divider set to 1 */
        __raw_writel(0x0101, uartinit_data[i].pdiv_clk_reg);

        /*
         * Force a flush of the RX FIFOs to work around a
         * HW bug
         */
        puart = uartinit_data[i].mapbase;
        __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
        __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
        j = LPC32XX_SUART_FIFO_SIZE;
        while (j--)
            tmp = __raw_readl(
                LPC32XX_UART_DLL_FIFO(puart));
        __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
    }

    /* This needs to be done after all UART clocks are setup */
    __raw_writel(clkmodes, LPC32XX_UARTCTL_CLKMODE);
    for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
        /* Force a flush of the RX FIFOs to work around a HW bug */
        puart = uartinit_data[i].mapbase;
        __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
        __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
        j = LPC32XX_SUART_FIFO_SIZE;
        while (j--)
            tmp = __raw_readl(LPC32XX_UART_DLL_FIFO(puart));
        __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
    }

    /* Disable IrDA pulsing support on UART6 */
    tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
    tmp |= LPC32XX_UART_UART6_IRDAMOD_BYPASS;
    __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);

    /* Disable UART5->USB transparent mode or USB won't work */
    tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
    tmp &= ~LPC32XX_UART_U5_ROUTE_TO_USB;
    __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);
}