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         resource_size_t mapbase;
  92 };
  93
  94 static struct uartinit uartinit_data[] __initdata = {
  95 #ifdef CONFIG_ARCH_LPC32XX_UART5_SELECT
  96         {
  97                 .uart_ck_name = "uart5_ck",
  98                 .ck_mode_mask =
  99                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 5),
 100                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART5_CLK_CTRL,
 101                 .mapbase = LPC32XX_UART5_BASE,
 102         },
 103 #endif
 104 #ifdef CONFIG_ARCH_LPC32XX_UART3_SELECT
 105         {
 106                 .uart_ck_name = "uart3_ck",
 107                 .ck_mode_mask =
 108                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 3),
 109                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART3_CLK_CTRL,
 110                 .mapbase = LPC32XX_UART3_BASE,
 111         },
 112 #endif
 113 #ifdef CONFIG_ARCH_LPC32XX_UART4_SELECT
 114         {
 115                 .uart_ck_name = "uart4_ck",
 116                 .ck_mode_mask =
 117                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 4),
 118                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART4_CLK_CTRL,
 119                 .mapbase = LPC32XX_UART4_BASE,
 120         },
 121 #endif
 122 #ifdef CONFIG_ARCH_LPC32XX_UART6_SELECT
 123         {
 124                 .uart_ck_name = "uart6_ck",
 125                 .ck_mode_mask =
 126                         LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 6),
 127                 .pdiv_clk_reg = LPC32XX_CLKPWR_UART6_CLK_CTRL,
 128                 .mapbase = LPC32XX_UART6_BASE,
 129         },
 130 #endif
 131 };
 132
 133 static struct platform_device serial_std_platform_device = {
 134         .name                   = "serial8250",
 135         .id                     = 0,
 136         .dev                    = {
 137                 .platform_data  = serial_std_platform_data,
 138         },
 139 };
 140
 141 static struct platform_device *lpc32xx_serial_devs[] __initdata = {
 142         &serial_std_platform_device,
 143 };
 144
 145 void __init lpc32xx_serial_init(void)
 146 {
 147         u32 tmp, clkmodes = 0;
 148         struct clk *clk;
 149         unsigned int puart;
 150         int i, j;
 151
 152         /* UART clocks are off, let clock driver manage them */
 153         __raw_writel(0, LPC32XX_CLKPWR_UART_CLK_CTRL);
 154
 155         for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
 156                 clk = clk_get(NULL, uartinit_data[i].uart_ck_name);
 157                 if (!IS_ERR(clk)) {
 158                         clk_enable(clk);
 159                         serial_std_platform_data[i].uartclk =
 160                                 clk_get_rate(clk);
 161                 }
 162
 163                 /* Fall back on main osc rate if clock rate return fails */
 164                 if (serial_std_platform_data[i].uartclk == 0)
 165                         serial_std_platform_data[i].uartclk =
 166                                 LPC32XX_MAIN_OSC_FREQ;
 167
 168                 /* Setup UART clock modes for all UARTs, disable autoclock */
 169                 clkmodes |= uartinit_data[i].ck_mode_mask;
 170
 171                 /* pre-UART clock divider set to 1 */
 172                 __raw_writel(0x0101, uartinit_data[i].pdiv_clk_reg);
 173
 174                 /*
 175                  * Force a flush of the RX FIFOs to work around a
 176                  * HW bug
 177                  */
 178                 puart = uartinit_data[i].mapbase;
 179                 __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
 180                 __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
 181                 j = LPC32XX_SUART_FIFO_SIZE;
 182                 while (j--)
 183                         tmp = __raw_readl(
 184                                 LPC32XX_UART_DLL_FIFO(puart));
 185                 __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
 186         }
 187
 188         /* This needs to be done after all UART clocks are setup */
 189         __raw_writel(clkmodes, LPC32XX_UARTCTL_CLKMODE);
 190         for (i = 0; i < ARRAY_SIZE(uartinit_data); i++) {
 191                 /* Force a flush of the RX FIFOs to work around a HW bug */
 192                 puart = serial_std_platform_data[i].mapbase;
 193                 __raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
 194                 __raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
 195                 j = LPC32XX_SUART_FIFO_SIZE;
 196                 while (j--)
 197                         tmp = __raw_readl(LPC32XX_UART_DLL_FIFO(puart));
 198                 __raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
 199         }
 200
 201         /* Disable UART5->USB transparent mode or USB won't work */
 202         tmp = __raw_readl(LPC32XX_UARTCTL_CTRL);
 203         tmp &= ~LPC32XX_UART_U5_ROUTE_TO_USB;
 204         __raw_writel(tmp, LPC32XX_UARTCTL_CTRL);
 205
 206         platform_add_devices(lpc32xx_serial_devs,
 207                 ARRAY_SIZE(lpc32xx_serial_devs));
 208 }