arch/arm/mach-ebsa110/core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/mach-ebsa110/core.c
   4  *
   5  *  Copyright (C) 1998-2001 Russell King
   6  *
   7  *  Extra MM routines for the EBSA-110 architecture
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/mm.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/serial_8250.h>
  13 #include <linux/init.h>
  14 #include <linux/io.h>
  15
  16 #include <mach/hardware.h>
  17 #include <asm/irq.h>
  18 #include <asm/setup.h>
  19 #include <asm/mach-types.h>
  20 #include <asm/page.h>
  21 #include <asm/system_misc.h>
  22
  23 #include <asm/mach/arch.h>
  24 #include <asm/mach/irq.h>
  25 #include <asm/mach/map.h>
  26
  27 #include <asm/mach/time.h>
  28
  29 #include "core.h"
  30
  31 static void ebsa110_mask_irq(struct irq_data *d)
  32 {
  33         __raw_writeb(1 << d->irq, IRQ_MCLR);
  34 }
  35
  36 static void ebsa110_unmask_irq(struct irq_data *d)
  37 {
  38         __raw_writeb(1 << d->irq, IRQ_MSET);
  39 }
  40
  41 static struct irq_chip ebsa110_irq_chip = {
  42         .irq_ack        = ebsa110_mask_irq,
  43         .irq_mask       = ebsa110_mask_irq,
  44         .irq_unmask     = ebsa110_unmask_irq,
  45 };
  46
  47 static void __init ebsa110_init_irq(void)
  48 {
  49         unsigned long flags;
  50         unsigned int irq;
  51
  52         local_irq_save(flags);
  53         __raw_writeb(0xff, IRQ_MCLR);
  54         __raw_writeb(0x55, IRQ_MSET);
  55         __raw_writeb(0x00, IRQ_MSET);
  56         if (__raw_readb(IRQ_MASK) != 0x55)
  57                 while (1);
  58         __raw_writeb(0xff, IRQ_MCLR);   /* clear all interrupt enables */
  59         local_irq_restore(flags);
  60
  61         for (irq = 0; irq < NR_IRQS; irq++) {
  62                 irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
  63                                          handle_level_irq);
  64                 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
  65         }
  66 }
  67
  68 static struct map_desc ebsa110_io_desc[] __initdata = {
  69         /*
  70          * sparse external-decode ISAIO space
  71          */
  72         {       /* IRQ_STAT/IRQ_MCLR */
  73                 .virtual        = (unsigned long)IRQ_STAT,
  74                 .pfn            = __phys_to_pfn(TRICK4_PHYS),
  75                 .length         = TRICK4_SIZE,
  76                 .type           = MT_DEVICE
  77         }, {    /* IRQ_MASK/IRQ_MSET */
  78                 .virtual        = (unsigned long)IRQ_MASK,
  79                 .pfn            = __phys_to_pfn(TRICK3_PHYS),
  80                 .length         = TRICK3_SIZE,
  81                 .type           = MT_DEVICE
  82         }, {    /* SOFT_BASE */
  83                 .virtual        = (unsigned long)SOFT_BASE,
  84                 .pfn            = __phys_to_pfn(TRICK1_PHYS),
  85                 .length         = TRICK1_SIZE,
  86                 .type           = MT_DEVICE
  87         }, {    /* PIT_BASE */
  88                 .virtual        = (unsigned long)PIT_BASE,
  89                 .pfn            = __phys_to_pfn(TRICK0_PHYS),
  90                 .length         = TRICK0_SIZE,
  91                 .type           = MT_DEVICE
  92         },
  93
  94         /*
  95          * self-decode ISAIO space
  96          */
  97         {
  98                 .virtual        = ISAIO_BASE,
  99                 .pfn            = __phys_to_pfn(ISAIO_PHYS),
 100                 .length         = ISAIO_SIZE,
 101                 .type           = MT_DEVICE
 102         }, {
 103                 .virtual        = ISAMEM_BASE,
 104                 .pfn            = __phys_to_pfn(ISAMEM_PHYS),
 105                 .length         = ISAMEM_SIZE,
 106                 .type           = MT_DEVICE
 107         }
 108 };
 109
 110 static void __init ebsa110_map_io(void)
 111 {
 112         iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
 113 }
 114
 115 static void __iomem *ebsa110_ioremap_caller(phys_addr_t cookie, size_t size,
 116                                             unsigned int flags, void *caller)
 117 {
 118         return (void __iomem *)cookie;
 119 }
 120
 121 static void ebsa110_iounmap(volatile void __iomem *io_addr)
 122 {}
 123
 124 static void __init ebsa110_init_early(void)
 125 {
 126         arch_ioremap_caller = ebsa110_ioremap_caller;
 127         arch_iounmap = ebsa110_iounmap;
 128 }
 129
 130 #define PIT_CTRL                (PIT_BASE + 0x0d)
 131 #define PIT_T2                  (PIT_BASE + 0x09)
 132 #define PIT_T1                  (PIT_BASE + 0x05)
 133 #define PIT_T0                  (PIT_BASE + 0x01)
 134
 135 /*
 136  * This is the rate at which your MCLK signal toggles (in Hz)
 137  * This was measured on a 10 digit frequency counter sampling
 138  * over 1 second.
 139  */
 140 #define MCLK    47894000
 141
 142 /*
 143  * This is the rate at which the PIT timers get clocked
 144  */
 145 #define CLKBY7  (MCLK / 7)
 146
 147 /*
 148  * This is the counter value.  We tick at 200Hz on this platform.
 149  */
 150 #define COUNT   ((CLKBY7 + (HZ / 2)) / HZ)
 151
 152 /*
 153  * Get the time offset from the system PIT.  Note that if we have missed an
 154  * interrupt, then the PIT counter will roll over (ie, be negative).
 155  * This actually works out to be convenient.
 156  */
 157 static u32 ebsa110_gettimeoffset(void)
 158 {
 159         unsigned long offset, count;
 160
 161         __raw_writeb(0x40, PIT_CTRL);
 162         count = __raw_readb(PIT_T1);
 163         count |= __raw_readb(PIT_T1) << 8;
 164
 165         /*
 166          * If count > COUNT, make the number negative.
 167          */
 168         if (count > COUNT)
 169                 count |= 0xffff0000;
 170
 171         offset = COUNT;
 172         offset -= count;
 173
 174         /*
 175          * `offset' is in units of timer counts.  Convert
 176          * offset to units of microseconds.
 177          */
 178         offset = offset * (1000000 / HZ) / COUNT;
 179
 180         return offset * 1000;
 181 }
 182
 183 static irqreturn_t
 184 ebsa110_timer_interrupt(int irq, void *dev_id)
 185 {
 186         u32 count;
 187
 188         /* latch and read timer 1 */
 189         __raw_writeb(0x40, PIT_CTRL);
 190         count = __raw_readb(PIT_T1);
 191         count |= __raw_readb(PIT_T1) << 8;
 192
 193         count += COUNT;
 194
 195         __raw_writeb(count & 0xff, PIT_T1);
 196         __raw_writeb(count >> 8, PIT_T1);
 197
 198         timer_tick();
 199
 200         return IRQ_HANDLED;
 201 }
 202
 203 /*
 204  * Set up timer interrupt.
 205  */
 206 void __init ebsa110_timer_init(void)
 207 {
 208         int irq = IRQ_EBSA110_TIMER0;
 209
 210         arch_gettimeoffset = ebsa110_gettimeoffset;
 211
 212         /*
 213          * Timer 1, mode 2, LSB/MSB
 214          */
 215         __raw_writeb(0x70, PIT_CTRL);
 216         __raw_writeb(COUNT & 0xff, PIT_T1);
 217         __raw_writeb(COUNT >> 8, PIT_T1);
 218
 219         if (request_irq(irq, ebsa110_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
 220                         "EBSA110 Timer Tick", NULL))
 221                 pr_err("Failed to request irq %d (EBSA110 Timer Tick)\n", irq);
 222 }
 223
 224 static struct plat_serial8250_port serial_platform_data[] = {
 225         {
 226                 .iobase         = 0x3f8,
 227                 .irq            = 1,
 228                 .uartclk        = 1843200,
 229                 .regshift       = 0,
 230                 .iotype         = UPIO_PORT,
 231                 .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 232         },
 233         {
 234                 .iobase         = 0x2f8,
 235                 .irq            = 2,
 236                 .uartclk        = 1843200,
 237                 .regshift       = 0,
 238                 .iotype         = UPIO_PORT,
 239                 .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 240         },
 241         { },
 242 };
 243
 244 static struct platform_device serial_device = {
 245         .name                   = "serial8250",
 246         .id                     = PLAT8250_DEV_PLATFORM,
 247         .dev                    = {
 248                 .platform_data  = serial_platform_data,
 249         },
 250 };
 251
 252 static struct resource am79c961_resources[] = {
 253         {
 254                 .start          = 0x220,
 255                 .end            = 0x238,
 256                 .flags          = IORESOURCE_IO,
 257         }, {
 258                 .start          = IRQ_EBSA110_ETHERNET,
 259                 .end            = IRQ_EBSA110_ETHERNET,
 260                 .flags          = IORESOURCE_IRQ,
 261         },
 262 };
 263
 264 static struct platform_device am79c961_device = {
 265         .name                   = "am79c961",
 266         .id                     = -1,
 267         .num_resources          = ARRAY_SIZE(am79c961_resources),
 268         .resource               = am79c961_resources,
 269 };
 270
 271 static struct platform_device *ebsa110_devices[] = {
 272         &serial_device,
 273         &am79c961_device,
 274 };
 275
 276 /*
 277  * EBSA110 idling methodology:
 278  *
 279  * We can not execute the "wait for interrupt" instruction since that
 280  * will stop our MCLK signal (which provides the clock for the glue
 281  * logic, and therefore the timer interrupt).
 282  *
 283  * Instead, we spin, polling the IRQ_STAT register for the occurrence
 284  * of any interrupt with core clock down to the memory clock.
 285  */
 286 static void ebsa110_idle(void)
 287 {
 288         const char *irq_stat = (char *)0xff000000;
 289
 290         /* disable clock switching */
 291         asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
 292
 293         /* wait for an interrupt to occur */
 294         while (!*irq_stat);
 295
 296         /* enable clock switching */
 297         asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
 298 }
 299
 300 static int __init ebsa110_init(void)
 301 {
 302         arm_pm_idle = ebsa110_idle;
 303         return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
 304 }
 305
 306 arch_initcall(ebsa110_init);
 307
 308 static void ebsa110_restart(enum reboot_mode mode, const char *cmd)
 309 {
 310         soft_restart(0x80000000);
 311 }
 312
 313 MACHINE_START(EBSA110, "EBSA110")
 314         /* Maintainer: Russell King */
 315         .atag_offset    = 0x400,
 316         .reserve_lp0    = 1,
 317         .reserve_lp2    = 1,
 318         .map_io         = ebsa110_map_io,
 319         .init_early     = ebsa110_init_early,
 320         .init_irq       = ebsa110_init_irq,
 321         .init_time      = ebsa110_timer_init,
 322         .restart        = ebsa110_restart,
 323 MACHINE_END