linux/arch/arm/mach-ebsa110/core.c
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   1/*
   2 *  linux/arch/arm/mach-ebsa110/core.c
   3 *
   4 *  Copyright (C) 1998-2001 Russell King
   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 version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 *  Extra MM routines for the EBSA-110 architecture
  11 */
  12#include <linux/kernel.h>
  13#include <linux/mm.h>
  14#include <linux/interrupt.h>
  15#include <linux/serial_8250.h>
  16#include <linux/init.h>
  17#include <linux/io.h>
  18
  19#include <mach/hardware.h>
  20#include <asm/irq.h>
  21#include <asm/setup.h>
  22#include <asm/mach-types.h>
  23#include <asm/pgtable.h>
  24#include <asm/page.h>
  25#include <asm/system_misc.h>
  26
  27#include <asm/mach/arch.h>
  28#include <asm/mach/irq.h>
  29#include <asm/mach/map.h>
  30
  31#include <asm/mach/time.h>
  32
  33#include "core.h"
  34
  35static void ebsa110_mask_irq(struct irq_data *d)
  36{
  37        __raw_writeb(1 << d->irq, IRQ_MCLR);
  38}
  39
  40static void ebsa110_unmask_irq(struct irq_data *d)
  41{
  42        __raw_writeb(1 << d->irq, IRQ_MSET);
  43}
  44
  45static struct irq_chip ebsa110_irq_chip = {
  46        .irq_ack        = ebsa110_mask_irq,
  47        .irq_mask       = ebsa110_mask_irq,
  48        .irq_unmask     = ebsa110_unmask_irq,
  49};
  50 
  51static void __init ebsa110_init_irq(void)
  52{
  53        unsigned long flags;
  54        unsigned int irq;
  55
  56        local_irq_save(flags);
  57        __raw_writeb(0xff, IRQ_MCLR);
  58        __raw_writeb(0x55, IRQ_MSET);
  59        __raw_writeb(0x00, IRQ_MSET);
  60        if (__raw_readb(IRQ_MASK) != 0x55)
  61                while (1);
  62        __raw_writeb(0xff, IRQ_MCLR);   /* clear all interrupt enables */
  63        local_irq_restore(flags);
  64
  65        for (irq = 0; irq < NR_IRQS; irq++) {
  66                irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
  67                                         handle_level_irq);
  68                irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
  69        }
  70}
  71
  72static struct map_desc ebsa110_io_desc[] __initdata = {
  73        /*
  74         * sparse external-decode ISAIO space
  75         */
  76        {       /* IRQ_STAT/IRQ_MCLR */
  77                .virtual        = (unsigned long)IRQ_STAT,
  78                .pfn            = __phys_to_pfn(TRICK4_PHYS),
  79                .length         = TRICK4_SIZE,
  80                .type           = MT_DEVICE
  81        }, {    /* IRQ_MASK/IRQ_MSET */
  82                .virtual        = (unsigned long)IRQ_MASK,
  83                .pfn            = __phys_to_pfn(TRICK3_PHYS),
  84                .length         = TRICK3_SIZE,
  85                .type           = MT_DEVICE
  86        }, {    /* SOFT_BASE */
  87                .virtual        = (unsigned long)SOFT_BASE,
  88                .pfn            = __phys_to_pfn(TRICK1_PHYS),
  89                .length         = TRICK1_SIZE,
  90                .type           = MT_DEVICE
  91        }, {    /* PIT_BASE */
  92                .virtual        = (unsigned long)PIT_BASE,
  93                .pfn            = __phys_to_pfn(TRICK0_PHYS),
  94                .length         = TRICK0_SIZE,
  95                .type           = MT_DEVICE
  96        },
  97
  98        /*
  99         * self-decode ISAIO space
 100         */
 101        {
 102                .virtual        = ISAIO_BASE,
 103                .pfn            = __phys_to_pfn(ISAIO_PHYS),
 104                .length         = ISAIO_SIZE,
 105                .type           = MT_DEVICE
 106        }, {
 107                .virtual        = ISAMEM_BASE,
 108                .pfn            = __phys_to_pfn(ISAMEM_PHYS),
 109                .length         = ISAMEM_SIZE,
 110                .type           = MT_DEVICE
 111        }
 112};
 113
 114static void __init ebsa110_map_io(void)
 115{
 116        iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
 117}
 118
 119static void __iomem *ebsa110_ioremap_caller(phys_addr_t cookie, size_t size,
 120                                            unsigned int flags, void *caller)
 121{
 122        return (void __iomem *)cookie;
 123}
 124
 125static void ebsa110_iounmap(volatile void __iomem *io_addr)
 126{}
 127
 128static void __init ebsa110_init_early(void)
 129{
 130        arch_ioremap_caller = ebsa110_ioremap_caller;
 131        arch_iounmap = ebsa110_iounmap;
 132}
 133
 134#define PIT_CTRL                (PIT_BASE + 0x0d)
 135#define PIT_T2                  (PIT_BASE + 0x09)
 136#define PIT_T1                  (PIT_BASE + 0x05)
 137#define PIT_T0                  (PIT_BASE + 0x01)
 138
 139/*
 140 * This is the rate at which your MCLK signal toggles (in Hz)
 141 * This was measured on a 10 digit frequency counter sampling
 142 * over 1 second.
 143 */
 144#define MCLK    47894000
 145
 146/*
 147 * This is the rate at which the PIT timers get clocked
 148 */
 149#define CLKBY7  (MCLK / 7)
 150
 151/*
 152 * This is the counter value.  We tick at 200Hz on this platform.
 153 */
 154#define COUNT   ((CLKBY7 + (HZ / 2)) / HZ)
 155
 156/*
 157 * Get the time offset from the system PIT.  Note that if we have missed an
 158 * interrupt, then the PIT counter will roll over (ie, be negative).
 159 * This actually works out to be convenient.
 160 */
 161static u32 ebsa110_gettimeoffset(void)
 162{
 163        unsigned long offset, count;
 164
 165        __raw_writeb(0x40, PIT_CTRL);
 166        count = __raw_readb(PIT_T1);
 167        count |= __raw_readb(PIT_T1) << 8;
 168
 169        /*
 170         * If count > COUNT, make the number negative.
 171         */
 172        if (count > COUNT)
 173                count |= 0xffff0000;
 174
 175        offset = COUNT;
 176        offset -= count;
 177
 178        /*
 179         * `offset' is in units of timer counts.  Convert
 180         * offset to units of microseconds.
 181         */
 182        offset = offset * (1000000 / HZ) / COUNT;
 183
 184        return offset * 1000;
 185}
 186
 187static irqreturn_t
 188ebsa110_timer_interrupt(int irq, void *dev_id)
 189{
 190        u32 count;
 191
 192        /* latch and read timer 1 */
 193        __raw_writeb(0x40, PIT_CTRL);
 194        count = __raw_readb(PIT_T1);
 195        count |= __raw_readb(PIT_T1) << 8;
 196
 197        count += COUNT;
 198
 199        __raw_writeb(count & 0xff, PIT_T1);
 200        __raw_writeb(count >> 8, PIT_T1);
 201
 202        timer_tick();
 203
 204        return IRQ_HANDLED;
 205}
 206
 207static struct irqaction ebsa110_timer_irq = {
 208        .name           = "EBSA110 Timer Tick",
 209        .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 210        .handler        = ebsa110_timer_interrupt,
 211};
 212
 213/*
 214 * Set up timer interrupt.
 215 */
 216void __init ebsa110_timer_init(void)
 217{
 218        arch_gettimeoffset = ebsa110_gettimeoffset;
 219
 220        /*
 221         * Timer 1, mode 2, LSB/MSB
 222         */
 223        __raw_writeb(0x70, PIT_CTRL);
 224        __raw_writeb(COUNT & 0xff, PIT_T1);
 225        __raw_writeb(COUNT >> 8, PIT_T1);
 226
 227        setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
 228}
 229
 230static struct plat_serial8250_port serial_platform_data[] = {
 231        {
 232                .iobase         = 0x3f8,
 233                .irq            = 1,
 234                .uartclk        = 1843200,
 235                .regshift       = 0,
 236                .iotype         = UPIO_PORT,
 237                .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 238        },
 239        {
 240                .iobase         = 0x2f8,
 241                .irq            = 2,
 242                .uartclk        = 1843200,
 243                .regshift       = 0,
 244                .iotype         = UPIO_PORT,
 245                .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 246        },
 247        { },
 248};
 249
 250static struct platform_device serial_device = {
 251        .name                   = "serial8250",
 252        .id                     = PLAT8250_DEV_PLATFORM,
 253        .dev                    = {
 254                .platform_data  = serial_platform_data,
 255        },
 256};
 257
 258static struct resource am79c961_resources[] = {
 259        {
 260                .start          = 0x220,
 261                .end            = 0x238,
 262                .flags          = IORESOURCE_IO,
 263        }, {
 264                .start          = IRQ_EBSA110_ETHERNET,
 265                .end            = IRQ_EBSA110_ETHERNET,
 266                .flags          = IORESOURCE_IRQ,
 267        },
 268};
 269
 270static struct platform_device am79c961_device = {
 271        .name                   = "am79c961",
 272        .id                     = -1,
 273        .num_resources          = ARRAY_SIZE(am79c961_resources),
 274        .resource               = am79c961_resources,
 275};
 276
 277static struct platform_device *ebsa110_devices[] = {
 278        &serial_device,
 279        &am79c961_device,
 280};
 281
 282/*
 283 * EBSA110 idling methodology:
 284 *
 285 * We can not execute the "wait for interrupt" instruction since that
 286 * will stop our MCLK signal (which provides the clock for the glue
 287 * logic, and therefore the timer interrupt).
 288 *
 289 * Instead, we spin, polling the IRQ_STAT register for the occurrence
 290 * of any interrupt with core clock down to the memory clock.
 291 */
 292static void ebsa110_idle(void)
 293{
 294        const char *irq_stat = (char *)0xff000000;
 295
 296        /* disable clock switching */
 297        asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
 298
 299        /* wait for an interrupt to occur */
 300        while (!*irq_stat);
 301
 302        /* enable clock switching */
 303        asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
 304}
 305
 306static int __init ebsa110_init(void)
 307{
 308        arm_pm_idle = ebsa110_idle;
 309        return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
 310}
 311
 312arch_initcall(ebsa110_init);
 313
 314static void ebsa110_restart(enum reboot_mode mode, const char *cmd)
 315{
 316        soft_restart(0x80000000);
 317}
 318
 319MACHINE_START(EBSA110, "EBSA110")
 320        /* Maintainer: Russell King */
 321        .atag_offset    = 0x400,
 322        .reserve_lp0    = 1,
 323        .reserve_lp2    = 1,
 324        .map_io         = ebsa110_map_io,
 325        .init_early     = ebsa110_init_early,
 326        .init_irq       = ebsa110_init_irq,
 327        .init_time      = ebsa110_timer_init,
 328        .restart        = ebsa110_restart,
 329MACHINE_END
 330