arch/arm/mach-lpc32xx/serial.c

   1 /*
   2  * arch/arm/mach-lpc32xx/serial.c
   3  *
   4  * Author: Kevin Wells <kevin.wells@nxp.com>
   5  *
   6  * Copyright (C) 2010 NXP Semiconductors
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/types.h>
  21 #include <linux/serial.h>
  22 #include <linux/serial_core.h>
  23 #include <linux/serial_reg.h>
  24 #include <linux/serial_8250.h>
  25 #include <linux/clk.h>
  26 #include <linux/io.h>
  27
  28 #include <mach/hardware.h>
  29 #include <mach/platform.h>
  30 #include "common.h"
  31
  32 #define LPC32XX_SUART_FIFO_SIZE 64
  33
  34 struct uartinit {
  35         char *uart_ck_name;
  36         u32 ck_mode_mask;
  37         void __iomem *pdiv_clk_reg;
  38         resource_size_t mapbase;
  39 };
  40
  41 static struct uartinit uartinit_data[] __initdata = {
  42         {
  43                 .uart_ck_name = "uart5_ck",
  44                 .ck_mode_mask =
  45                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 5),
  46                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART5_CLK_CTRL,
  47                 .mapbase = LPC32XX_UART5_BASE,
  48         },
  49         {
  50                 .uart_ck_name = "uart3_ck",
  51                 .ck_mode_mask =
  52                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 3),
  53                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART3_CLK_CTRL,
  54                 .mapbase = LPC32XX_UART3_BASE,
  55         },
  56         {
  57                 .uart_ck_name = "uart4_ck",
  58                 .ck_mode_mask =
  59                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 4),
  60                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART4_CLK_CTRL,
  61                 .mapbase = LPC32XX_UART4_BASE,
  62         },
  63         {
  64                 .uart_ck_name = "uart6_ck",
  65                 .ck_mode_mask =
  66                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 6),
  67                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART6_CLK_CTRL,
  68                 .mapbase = LPC32XX_UART6_BASE,
  69         },
  70 };
  71
  72 void __init lpc32xx_serial_init(void)
  73 {
  74         u32 tmp, clkmodes = 0;
  75         struct clk *clk;
  76         unsigned int puart;
  77         int i, j;
  78
  79         /* UART clocks are off, let clock driver manage them */
  80         __raw_writel(0, LPC32XX_CLKPWR_UART_CLK_CTRL);
  81
  82         for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
  83                 clk = clk_get(NULL, uartinit_data[i].uart_ck_name);
  84                 if (!IS_ERR(clk)) {
  85                         clk_enable(clk);
  86                 }
  87
  88                 /* Setup UART clock modes for all UARTs, disable autoclock */
  89                 clkmodes |= uartinit_data[i].ck_mode_mask;
  90
  91                 /* pre-UART clock divider set to 1 */
  92                 __raw_writel(0x0101, uartinit_data[i].pdiv_clk_reg);
  93
  94                 /*
  95                  * Force a flush of the RX FIFOs to work around a
  96                  * HW bug
  97                  */
  98                 puart = uartinit_data[i].mapbase;
  99                 __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
 100                 __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
 101                 j = LPC32XX_SUART_FIFO_SIZE;
 102                 while (j--)
 103                         tmp = __raw_readl(
 104                                 LPC32XX_UART_DLL_FIFO(puart));
 105                 __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
 106         }
 107
 108         /* This needs to be done after all UART clocks are setup */
 109         __raw_writel(clkmodes, LPC32XX_UARTCTL_CLKMODE);
 110         for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
 111                 /* Force a flush of the RX FIFOs to work around a HW bug */
 112                 puart = uartinit_data[i].mapbase;
 113                 __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
 114                 __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
 115                 j = LPC32XX_SUART_FIFO_SIZE;
 116                 while (j--)
 117                         tmp = __raw_readl(LPC32XX_UART_DLL_FIFO(puart));
 118                 __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
 119         }
 120
 121         /* Disable IrDA pulsing support on UART6 */
 122         tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
 123         tmp |= LPC32XX_UART_UART6_IRDAMOD_BYPASS;
 124         __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);
 125
 126         /* Disable UART5->USB transparent mode or USB won't work */
 127         tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
 128         tmp &= ~LPC32XX_UART_U5_ROUTE_TO_USB;
 129         __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);
 130 }