arch/arm/mach-clps711x/common.c

   1 /*
   2  *  linux/arch/arm/mach-clps711x/core.c
   3  *
   4  *  Core support for the CLPS711x-based machines.
   5  *
   6  *  Copyright (C) 2001,2011 Deep Blue Solutions Ltd
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22 #include <linux/io.h>
  23 #include <linux/init.h>
  24 #include <linux/sizes.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/irq.h>
  27 #include <linux/clk.h>
  28 #include <linux/clkdev.h>
  29 #include <linux/clockchips.h>
  30 #include <linux/clocksource.h>
  31 #include <linux/clk-provider.h>
  32 #include <linux/sched_clock.h>
  33
  34 #include <asm/mach/map.h>
  35 #include <asm/mach/time.h>
  36 #include <asm/system_misc.h>
  37
  38 #include <mach/hardware.h>
  39
  40 #include "common.h"
  41
  42 static struct clk *clk_pll, *clk_bus, *clk_uart, *clk_timerl, *clk_timerh,
  43                   *clk_tint, *clk_spi;
  44
  45 /*
  46  * This maps the generic CLPS711x registers
  47  */
  48 static struct map_desc clps711x_io_desc[] __initdata = {
  49         {
  50                 .virtual        = (unsigned long)CLPS711X_VIRT_BASE,
  51                 .pfn            = __phys_to_pfn(CLPS711X_PHYS_BASE),
  52                 .length         = SZ_64K,
  53                 .type           = MT_DEVICE
  54         }
  55 };
  56
  57 void __init clps711x_map_io(void)
  58 {
  59         iotable_init(clps711x_io_desc, ARRAY_SIZE(clps711x_io_desc));
  60 }
  61
  62 void __init clps711x_init_irq(void)
  63 {
  64         clps711x_intc_init(CLPS711X_PHYS_BASE, SZ_16K);
  65 }
  66
  67 static u64 notrace clps711x_sched_clock_read(void)
  68 {
  69         return ~readw_relaxed(CLPS711X_VIRT_BASE + TC1D);
  70 }
  71
  72 static void clps711x_clockevent_set_mode(enum clock_event_mode mode,
  73                                          struct clock_event_device *evt)
  74 {
  75         disable_irq(IRQ_TC2OI);
  76
  77         switch (mode) {
  78         case CLOCK_EVT_MODE_PERIODIC:
  79                 enable_irq(IRQ_TC2OI);
  80                 break;
  81         case CLOCK_EVT_MODE_ONESHOT:
  82                 /* Not supported */
  83         case CLOCK_EVT_MODE_SHUTDOWN:
  84         case CLOCK_EVT_MODE_UNUSED:
  85         case CLOCK_EVT_MODE_RESUME:
  86                 /* Left event sources disabled, no more interrupts appear */
  87                 break;
  88         }
  89 }
  90
  91 static struct clock_event_device clockevent_clps711x = {
  92         .name           = "clps711x-clockevent",
  93         .rating         = 300,
  94         .features       = CLOCK_EVT_FEAT_PERIODIC,
  95         .set_mode       = clps711x_clockevent_set_mode,
  96 };
  97
  98 static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
  99 {
 100         clockevent_clps711x.event_handler(&clockevent_clps711x);
 101
 102         return IRQ_HANDLED;
 103 }
 104
 105 static struct irqaction clps711x_timer_irq = {
 106         .name           = "clps711x-timer",
 107         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 108         .handler        = clps711x_timer_interrupt,
 109 };
 110
 111 static void add_fixed_clk(struct clk *clk, const char *name, int rate)
 112 {
 113         clk = clk_register_fixed_rate(NULL, name, NULL, CLK_IS_ROOT, rate);
 114         clk_register_clkdev(clk, name, NULL);
 115 }
 116
 117 void __init clps711x_timer_init(void)
 118 {
 119         int osc, ext, pll, cpu, bus, timl, timh, uart, spi;
 120         u32 tmp;
 121
 122         osc = 3686400;
 123         ext = 13000000;
 124
 125         tmp = clps_readl(PLLR) >> 24;
 126         if (tmp)
 127                 pll = (osc * tmp) / 2;
 128         else
 129                 pll = 73728000; /* Default value */
 130
 131         tmp = clps_readl(SYSFLG2);
 132         if (tmp & SYSFLG2_CKMODE) {
 133                 cpu = ext;
 134                 bus = cpu;
 135                 spi = 135400;
 136                 pll = 0;
 137         } else {
 138                 cpu = pll;
 139                 if (cpu >= 36864000)
 140                         bus = cpu / 2;
 141                 else
 142                         bus = 36864000 / 2;
 143                 spi = cpu / 576;
 144         }
 145
 146         uart = bus / 10;
 147
 148         if (tmp & SYSFLG2_CKMODE) {
 149                 tmp = clps_readl(SYSCON2);
 150                 if (tmp & SYSCON2_OSTB)
 151                         timh = ext / 26;
 152                 else
 153                         timh = 541440;
 154         } else
 155                 timh = DIV_ROUND_CLOSEST(cpu, 144);
 156
 157         timl = DIV_ROUND_CLOSEST(timh, 256);
 158
 159         /* All clocks are fixed */
 160         add_fixed_clk(clk_pll, "pll", pll);
 161         add_fixed_clk(clk_bus, "bus", bus);
 162         add_fixed_clk(clk_uart, "uart", uart);
 163         add_fixed_clk(clk_timerl, "timer_lf", timl);
 164         add_fixed_clk(clk_timerh, "timer_hf", timh);
 165         add_fixed_clk(clk_tint, "tint", 64);
 166         add_fixed_clk(clk_spi, "spi", spi);
 167
 168         pr_info("CPU frequency set at %i Hz.\n", cpu);
 169
 170         /* Start Timer1 in free running mode (Low frequency) */
 171         tmp = clps_readl(SYSCON1) & ~(SYSCON1_TC1S | SYSCON1_TC1M);
 172         clps_writel(tmp, SYSCON1);
 173
 174         sched_clock_register(clps711x_sched_clock_read, 16, timl);
 175
 176         clocksource_mmio_init(CLPS711X_VIRT_BASE + TC1D,
 177                               "clps711x_clocksource", timl, 300, 16,
 178                               clocksource_mmio_readw_down);
 179
 180         /* Set Timer2 prescaler */
 181         clps_writew(DIV_ROUND_CLOSEST(timh, HZ), TC2D);
 182
 183         /* Start Timer2 in prescale mode (High frequency)*/
 184         tmp = clps_readl(SYSCON1) | SYSCON1_TC2M | SYSCON1_TC2S;
 185         clps_writel(tmp, SYSCON1);
 186
 187         clockevents_config_and_register(&clockevent_clps711x, timh, 0, 0);
 188
 189         setup_irq(IRQ_TC2OI, &clps711x_timer_irq);
 190 }
 191
 192 void clps711x_restart(enum reboot_mode mode, const char *cmd)
 193 {
 194         soft_restart(0);
 195 }