arch/arm/mach-ebsa110/core.c

   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
  35 static void ebsa110_mask_irq(struct irq_data *d)
  36 {
  37         __raw_writeb(1 << d->irq, IRQ_MCLR);
  38 }
  39
  40 static void ebsa110_unmask_irq(struct irq_data *d)
  41 {
  42         __raw_writeb(1 << d->irq, IRQ_MSET);
  43 }
  44
  45 static 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
  51 static 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
  72 static 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
 114 static void __init ebsa110_map_io(void)
 115 {
 116         iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
 117 }
 118
 119 static 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
 125 static void ebsa110_iounmap(volatile void __iomem *io_addr)
 126 {}
 127
 128 static 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  */
 161 static 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
 187 static irqreturn_t
 188 ebsa110_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
 207 static 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  */
 216 void __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
 230 static 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
 250 static struct platform_device serial_device = {
 251         .name                   = "serial8250",
 252         .id                     = PLAT8250_DEV_PLATFORM,
 253         .dev                    = {
 254                 .platform_data  = serial_platform_data,
 255         },
 256 };
 257
 258 static 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
 270 static struct platform_device am79c961_device = {
 271         .name                   = "am79c961",
 272         .id                     = -1,
 273         .num_resources          = ARRAY_SIZE(am79c961_resources),
 274         .resource               = am79c961_resources,
 275 };
 276
 277 static 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  */
 292 static 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
 306 static 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
 312 arch_initcall(ebsa110_init);
 313
 314 static void ebsa110_restart(enum reboot_mode mode, const char *cmd)
 315 {
 316         soft_restart(0x80000000);
 317 }
 318
 319 MACHINE_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,
 329 MACHINE_END