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 /* Standard 8250/16550 compatible serial ports */
  35 static struct plat_serial8250_port serial_std_platform_data[] = {
  36 #ifdef CONFIG_ARCH_LPC32XX_UART5_SELECT
  37         {
  38                 .membase        = io_p2v(LPC32XX_UART5_BASE),
  39                 .mapbase        = LPC32XX_UART5_BASE,
  40                 .irq            = IRQ_LPC32XX_UART_IIR5,
  41                 .uartclk        = LPC32XX_MAIN_OSC_FREQ,
  42                 .regshift       = 2,
  43                 .iotype         = UPIO_MEM32,
  44                 .flags          = UPF_BOOT_AUTOCONF | UPF_BUGGY_UART |
  45                                         UPF_SKIP_TEST,
  46         },
  47 #endif
  48 #ifdef CONFIG_ARCH_LPC32XX_UART3_SELECT
  49         {
  50                 .membase        = io_p2v(LPC32XX_UART3_BASE),
  51                 .mapbase        = LPC32XX_UART3_BASE,
  52                 .irq            = IRQ_LPC32XX_UART_IIR3,
  53                 .uartclk        = LPC32XX_MAIN_OSC_FREQ,
  54                 .regshift       = 2,
  55                 .iotype         = UPIO_MEM32,
  56                 .flags          = UPF_BOOT_AUTOCONF | UPF_BUGGY_UART |
  57                                         UPF_SKIP_TEST,
  58         },
  59 #endif
  60 #ifdef CONFIG_ARCH_LPC32XX_UART4_SELECT
  61         {
  62                 .membase        = io_p2v(LPC32XX_UART4_BASE),
  63                 .mapbase        = LPC32XX_UART4_BASE,
  64                 .irq            = IRQ_LPC32XX_UART_IIR4,
  65                 .uartclk        = LPC32XX_MAIN_OSC_FREQ,
  66                 .regshift       = 2,
  67                 .iotype         = UPIO_MEM32,
  68                 .flags          = UPF_BOOT_AUTOCONF | UPF_BUGGY_UART |
  69                                         UPF_SKIP_TEST,
  70         },
  71 #endif
  72 #ifdef CONFIG_ARCH_LPC32XX_UART6_SELECT
  73         {
  74                 .membase        = io_p2v(LPC32XX_UART6_BASE),
  75                 .mapbase        = LPC32XX_UART6_BASE,
  76                 .irq            = IRQ_LPC32XX_UART_IIR6,
  77                 .uartclk        = LPC32XX_MAIN_OSC_FREQ,
  78                 .regshift       = 2,
  79                 .iotype         = UPIO_MEM32,
  80                 .flags          = UPF_BOOT_AUTOCONF | UPF_BUGGY_UART |
  81                                         UPF_SKIP_TEST,
  82         },
  83 #endif
  84         { },
  85 };
  86
  87 struct uartinit {
  88         char *uart_ck_name;
  89         u32 ck_mode_mask;
  90         void __iomem *pdiv_clk_reg;
  91 };
  92
  93 static struct uartinit uartinit_data[] __initdata = {
  94 #ifdef CONFIG_ARCH_LPC32XX_UART5_SELECT
  95         {
  96                 .uart_ck_name = "uart5_ck",
  97                 .ck_mode_mask =
  98                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 5),
  99                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART5_CLK_CTRL,
 100         },
 101 #endif
 102 #ifdef CONFIG_ARCH_LPC32XX_UART3_SELECT
 103         {
 104                 .uart_ck_name = "uart3_ck",
 105                 .ck_mode_mask =
 106                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 3),
 107                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART3_CLK_CTRL,
 108         },
 109 #endif
 110 #ifdef CONFIG_ARCH_LPC32XX_UART4_SELECT
 111         {
 112                 .uart_ck_name = "uart4_ck",
 113                 .ck_mode_mask =
 114                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 4),
 115                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART4_CLK_CTRL,
 116         },
 117 #endif
 118 #ifdef CONFIG_ARCH_LPC32XX_UART6_SELECT
 119         {
 120                 .uart_ck_name = "uart6_ck",
 121                 .ck_mode_mask =
 122                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 6),
 123                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART6_CLK_CTRL,
 124         },
 125 #endif
 126 };
 127
 128 static struct platform_device serial_std_platform_device = {
 129         .name                   = "serial8250",
 130         .id                     = 0,
 131         .dev                    = {
 132                 .platform_data  = serial_std_platform_data,
 133         },
 134 };
 135
 136 static struct platform_device *lpc32xx_serial_devs[] __initdata = {
 137         &serial_std_platform_device,
 138 };
 139
 140 void __init lpc32xx_serial_init(void)
 141 {
 142         u32 tmp, clkmodes = 0;
 143         struct clk *clk;
 144         unsigned int puart;
 145         int i, j;
 146
 147         /* UART clocks are off, let clock driver manage them */
 148         __raw_writel(0, LPC32XX_CLKPWR_UART_CLK_CTRL);
 149
 150         for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
 151                 clk = clk_get(NULL, uartinit_data[i].uart_ck_name);
 152                 if (!IS_ERR(clk)) {
 153                         clk_enable(clk);
 154                         serial_std_platform_data[i].uartclk =
 155                                 clk_get_rate(clk);
 156                 }
 157
 158                 /* Fall back on main osc rate if clock rate return fails */
 159                 if (serial_std_platform_data[i].uartclk == 0)
 160                         serial_std_platform_data[i].uartclk =
 161                                 LPC32XX_MAIN_OSC_FREQ;
 162
 163                 /* Setup UART clock modes for all UARTs, disable autoclock */
 164                 clkmodes |= uartinit_data[i].ck_mode_mask;
 165
 166                 /* pre-UART clock divider set to 1 */
 167                 __raw_writel(0x0101, uartinit_data[i].pdiv_clk_reg);
 168         }
 169
 170         /* This needs to be done after all UART clocks are setup */
 171         __raw_writel(clkmodes, LPC32XX_UARTCTL_CLKMODE);
 172         for (i = 0; i < ARRAY_SIZE(uartinit_data) - 1; i++) {
 173                 /* Force a flush of the RX FIFOs to work around a HW bug */
 174                 puart = serial_std_platform_data[i].mapbase;
 175                 __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
 176                 __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
 177                 j = LPC32XX_SUART_FIFO_SIZE;
 178                 while (j--)
 179                         tmp = __raw_readl(LPC32XX_UART_DLL_FIFO(puart));
 180                 __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
 181         }
 182
 183         /* Disable UART5->USB transparent mode or USB won't work */
 184         tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
 185         tmp &= ~LPC32XX_UART_U5_ROUTE_TO_USB;
 186         __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);
 187
 188         platform_add_devices(lpc32xx_serial_devs,
 189                 ARRAY_SIZE(lpc32xx_serial_devs));
 190 }