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