arch/arm/mach-davinci/serial.c

   1 /*
   2  * TI DaVinci serial driver
   3  *
   4  * Copyright (C) 2006 Texas Instruments.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/serial_8250.h>
  25 #include <linux/serial_reg.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/delay.h>
  28 #include <linux/clk.h>
  29 #include <linux/io.h>
  30
  31 #include <asm/irq.h>
  32 #include <mach/hardware.h>
  33 #include <mach/serial.h>
  34 #include <mach/irqs.h>
  35 #include <mach/cputype.h>
  36 #include "clock.h"
  37
  38 static inline unsigned int serial_read_reg(struct plat_serial8250_port *up,
  39                                            int offset)
  40 {
  41         offset <<= up->regshift;
  42         return (unsigned int)__raw_readl(IO_ADDRESS(up->mapbase) + offset);
  43 }
  44
  45 static inline void serial_write_reg(struct plat_serial8250_port *p, int offset,
  46                                     int value)
  47 {
  48         offset <<= p->regshift;
  49         __raw_writel(value, IO_ADDRESS(p->mapbase) + offset);
  50 }
  51
  52 static struct plat_serial8250_port serial_platform_data[] = {
  53         {
  54                 .mapbase        = DAVINCI_UART0_BASE,
  55                 .irq            = IRQ_UARTINT0,
  56                 .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST |
  57                                   UPF_IOREMAP,
  58                 .iotype         = UPIO_MEM,
  59                 .regshift       = 2,
  60         },
  61         {
  62                 .mapbase        = DAVINCI_UART1_BASE,
  63                 .irq            = IRQ_UARTINT1,
  64                 .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST |
  65                                   UPF_IOREMAP,
  66                 .iotype         = UPIO_MEM,
  67                 .regshift       = 2,
  68         },
  69         {
  70                 .mapbase        = DAVINCI_UART2_BASE,
  71                 .irq            = IRQ_UARTINT2,
  72                 .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST |
  73                                   UPF_IOREMAP,
  74                 .iotype         = UPIO_MEM,
  75                 .regshift       = 2,
  76         },
  77         {
  78                 .flags          = 0
  79         },
  80 };
  81
  82 static struct platform_device serial_device = {
  83         .name                   = "serial8250",
  84         .id                     = PLAT8250_DEV_PLATFORM,
  85         .dev                    = {
  86                 .platform_data  = serial_platform_data,
  87         },
  88 };
  89
  90 static void __init davinci_serial_reset(struct plat_serial8250_port *p)
  91 {
  92         unsigned int pwremu = 0;
  93
  94         serial_write_reg(p, UART_IER, 0);  /* disable all interrupts */
  95
  96         /* reset both transmitter and receiver: bits 14,13 = UTRST, URRST */
  97         serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
  98         mdelay(10);
  99
 100         pwremu |= (0x3 << 13);
 101         pwremu |= 0x1;
 102         serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
 103
 104         if (cpu_is_davinci_dm646x())
 105                 serial_write_reg(p, UART_DM646X_SCR,
 106                                  UART_DM646X_SCR_TX_WATERMARK);
 107 }
 108
 109 void __init davinci_serial_init(struct davinci_uart_config *info)
 110 {
 111         int i;
 112         char name[16];
 113         struct clk *uart_clk;
 114         struct device *dev = &serial_device.dev;
 115
 116         /*
 117          * Make sure the serial ports are muxed on at this point.
 118          * You have to mux them off in device drivers later on
 119          * if not needed.
 120          */
 121         for (i = 0; i < DAVINCI_MAX_NR_UARTS; i++) {
 122                 struct plat_serial8250_port *p = serial_platform_data + i;
 123
 124                 if (!(info->enabled_uarts & (1 << i))) {
 125                         p->flags = 0;
 126                         continue;
 127                 }
 128
 129                 if (cpu_is_davinci_dm646x())
 130                         p->iotype = UPIO_MEM32;
 131
 132                 if (cpu_is_davinci_dm355()) {
 133                         if (i == 2) {
 134                                 p->mapbase = (unsigned long)DM355_UART2_BASE;
 135                                 p->irq = IRQ_DM355_UARTINT2;
 136                         }
 137                 }
 138
 139                 sprintf(name, "uart%d", i);
 140                 uart_clk = clk_get(dev, name);
 141                 if (IS_ERR(uart_clk))
 142                         printk(KERN_ERR "%s:%d: failed to get UART%d clock\n",
 143                                         __func__, __LINE__, i);
 144                 else {
 145                         clk_enable(uart_clk);
 146                         p->uartclk = clk_get_rate(uart_clk);
 147                         davinci_serial_reset(p);
 148                 }
 149         }
 150 }
 151
 152 static int __init davinci_init(void)
 153 {
 154         return platform_device_register(&serial_device);
 155 }
 156
 157 arch_initcall(davinci_init);