arch/arm/mach-p2001/time.c

   1 /*
   2  *  linux/arch/arm/mach-p2001/time.c
   3  *
   4  *  Copyright (C) 2004-2005 Tobias Lorenz
   5  *
   6  *  Timer handling code
   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 version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include <linux/timex.h>
  22 #include <linux/init.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/sched.h>
  25
  26 #ifdef CONFIG_CPU_FREQ
  27 #include <linux/notifier.h>
  28 #include <linux/cpufreq.h>
  29 #endif
  30
  31 #include <asm/hardware.h>
  32 #include <asm/irq.h>
  33 #include <asm/leds.h>
  34 #include <asm/io.h>
  35
  36 #include <asm/mach/time.h>
  37
  38 #define P2001_TIMER_VALUE(reg, mask, shift, value) { \
  39         unsigned int i = (P2001_TIMER->reg); \
  40         i &= ~((mask) << (shift)); \
  41         i |= (((value) & (mask)) << (shift)); \
  42         (P2001_TIMER->reg) = i; \
  43 }
  44
  45 /*
  46  * short calculation
  47  * ---------------------------------------------------------------
  48  * prescaler = factor * (SYSCLK / 12288000)             max: 255
  49  * period = SYSCLK/prescaler/HZ                         max: 65535
  50  * clocks_per_usec = SYSCLK/prescaler / 1000000         min: 1
  51  *                 = 12288000 / factor / 1000000
  52  * ---------------------------------------------------------------
  53  * IMPORTANT: recalculate factor when HZ changes, so that limits
  54  * are kept within SYSCLK range (12288000-73728000)
  55  */
  56
  57 /**************************************************************************
  58  * Timer 1: Scheduler
  59  **************************************************************************/
  60 #define TIMER1_HZ       HZ      /* 100-1000 HZ */
  61 #define TIMER1_FACTOR   2
  62
  63 static irqreturn_t p2001_timer1_interrupt(int irq, void *dev_id)
  64 {
  65         write_seqlock(&xtime_lock);
  66
  67         timer_tick();
  68
  69         /* clear interrupt pending bit */
  70         P2001_TIMER->TIMER_INT &= ~(1<<0);              // Timer1_Int
  71
  72         write_sequnlock(&xtime_lock);
  73
  74         return IRQ_HANDLED;
  75 }
  76
  77 static struct irqaction p2001_timer1_irq = {
  78         .name           = "P2001 timer1",
  79         .flags          = IRQF_DISABLED | IRQF_TIMER,
  80         .handler        = p2001_timer1_interrupt,
  81 };
  82
  83 /* Return number of microseconds since last interrupt */
  84 #define TIMER1_CLOCKS_PER_USEC (12288000/TIMER1_FACTOR/1000000)
  85 static unsigned long p2001_gettimeoffset(void)
  86 {
  87         return ((0xffff - P2001_TIMER->Timer1) & 0xffff) / TIMER1_CLOCKS_PER_USEC;
  88 }
  89
  90 #ifdef CONFIG_CPU_FREQ
  91 /*
  92  * Transistion notifier
  93  */
  94 static int p2001_timer1_notifier(struct notifier_block *self, unsigned long phase, void *data)
  95 {
  96         struct cpufreq_freqs *cf = data;
  97         unsigned int prescaler, period;
  98
  99         if ((phase == CPUFREQ_POSTCHANGE) ||
 100             (phase == CPUFREQ_RESUMECHANGE)) {
 101                 prescaler = TIMER1_FACTOR*cf->new/12288;
 102                 period = (1000*cf->new/prescaler)/TIMER1_HZ;
 103                 P2001_TIMER_VALUE(TIMER_PRELOAD, 0xffff, 0, period);
 104                 P2001_TIMER_VALUE(Timer12_PreDiv, 0xff, 0, prescaler - 1);
 105         }
 106
 107         return NOTIFY_OK;
 108 }
 109
 110 static struct notifier_block p2001_timer1_nb = { &p2001_timer1_notifier, NULL, 0 };
 111 #endif /* CONFIG_CPU_FREQ */
 112
 113 static void p2001_timer1_init(void)
 114 {
 115         unsigned int prescaler, period;
 116
 117         /* initialize the timer period and prescaler */
 118         prescaler = TIMER1_FACTOR*(CONFIG_SYSCLK/12288000);
 119         period = (CONFIG_SYSCLK/prescaler)/TIMER1_HZ;
 120         P2001_TIMER_VALUE(TIMER_PRELOAD, 0xffff, 0, period);
 121         P2001_TIMER_VALUE(Timer12_PreDiv, 0xff, 0, prescaler - 1);
 122
 123         /* set up the interrupt vector for timer 1 match */
 124         setup_irq(IRQ_TIMER1, &p2001_timer1_irq);
 125
 126         /* enable the timer IRQ */
 127         P2001_TIMER->TIMER_INT |= (1<<4);               // Timer1_Int_En
 128
 129         /* let timer 1 run... */
 130         P2001_TIMER->Timer12_PreDiv &= ~(1<<28);        // Timer_1_Disable
 131
 132 #ifdef CONFIG_CPU_FREQ
 133         cpufreq_register_notifier(&p2001_timer1_nb, CPUFREQ_TRANSITION_NOTIFIER);
 134 #endif
 135 }
 136
 137
 138 /**************************************************************************
 139  * Timer 2: LED Frequency Indicator
 140  **************************************************************************/
 141 #ifdef CONFIG_P2001_TIMER2_LED_FREQ_INDICATOR
 142 #define TIMER2_HZ       10
 143 #define TIMER2_FACTOR   20
 144
 145 static irqreturn_t p2001_timer2_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 146 {
 147         unsigned int gpio2;
 148
 149         /* switch leds */
 150         gpio2 = P2001_GPIO->GPIO2_Out;
 151         if (gpio2 & 0x0040) {
 152                 /* gpio23_v4 on */
 153                 gpio2 &= ~0x00c0;
 154                 gpio2 |= 0x0080;
 155         } else {
 156                 /* gpio22_v5 on */
 157                 gpio2 &= ~0x00c0;
 158                 gpio2 |= 0x0040;
 159         }
 160         P2001_GPIO->GPIO2_Out = gpio2;
 161
 162         /* clear interrupt pending bit */
 163         P2001_TIMER->TIMER_INT &= ~(1<<1);              // Timer2_Int
 164
 165         return IRQ_HANDLED;
 166 }
 167
 168 static struct irqaction p2001_timer2_irq = {
 169         .name           = "P2001 timer2",
 170         .flags          = SA_INTERRUPT,
 171         .handler        = p2001_timer2_interrupt,
 172 };
 173
 174 static void p2001_timer2_init(void)
 175 {
 176         unsigned int prescaler, period;
 177
 178         /* initialize the timer period and prescaler */
 179         prescaler = TIMER2_FACTOR*(CONFIG_SYSCLK/12288000);
 180         period = (CONFIG_SYSCLK/prescaler)/TIMER2_HZ;
 181         P2001_TIMER_VALUE(TIMER_PRELOAD, 0xffff, 16, period);
 182         P2001_TIMER_VALUE(Timer12_PreDiv, 0xff, 8, prescaler - 1);
 183
 184         /* Activate Leds Frequency Indicator */
 185         /* Schematics say that: SDO_2/GPIO_22=V5, SDI_2/GPIO_23=V4 */
 186         P2001_GPIO->PIN_MUX |= (1<<2);                  // set MUX to GPIOs
 187         P2001_GPIO->GPIO2_En |= 0xC0;                   // Enable GPIO driver
 188         P2001_GPIO->GPIO2_Out |= 0x00C00000;            // Mask bits
 189
 190         /* set up the interrupt vector for timer 2 match */
 191         setup_irq(IRQ_TIMER2, &p2001_timer2_irq);
 192
 193         /* enable the timer IRQ */
 194         P2001_TIMER->TIMER_INT |= (1<<5);               // Timer2_Int_En
 195
 196         /* let timer 2 run... */
 197         P2001_TIMER->Timer12_PreDiv &= ~(1<<29);        // Timer_2_Disable
 198 }
 199 #endif
 200
 201
 202 /**************************************************************************
 203  * Watchdog
 204  **************************************************************************/
 205 #ifdef CONFIG_P2001_WATCHDOG
 206 static irqreturn_t p2001_wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 207 {
 208         // printk(KERN_CRIT "Critical watchdog value reached: %d!\n", P2001_TIMER->WatchDog_Timer);
 209
 210         /* Reset watchdog */
 211         P2001_TIMER->Timer12_PreDiv |= (1<<31);         // WatchDog_Reset
 212
 213         /* clear interrupt pending bit */
 214         P2001_TIMER->TIMER_INT &= ~(1<<2);              // WatchDog_Int
 215
 216         return IRQ_HANDLED;
 217 }
 218
 219 static struct irqaction p2001_wdt_irq = {
 220         .name           = "P2001 watchdog",
 221         .flags          = SA_INTERRUPT,
 222         .handler        = p2001_wdt_interrupt,
 223 };
 224
 225 static void p2001_wdt_init(void)
 226 {
 227         /* Set predivider, so that watchdog runs at 3000 Hz */
 228         /* Reset after 65536/3000 = 21.85 secs (75 MHz) */
 229         P2001_TIMER->Timer12_PreDiv |= (0xfff << 16);   // PreDiv_WatchDog
 230
 231         /* Reset watchdog */
 232         P2001_TIMER->Timer12_PreDiv |= (1<<31);         // WatchDog_Reset
 233
 234         /* Warning after 30000/3000 = 10 secs passed */
 235         P2001_TIMER->TIMER_INT |= (1<<6);               // WatchDog_Int_En
 236         P2001_TIMER->TIMER_INT &= 0xff;                 // WatchDog_Int_Level
 237         P2001_TIMER->TIMER_INT |= (30000 << 8);         // WatchDog_Int_Level
 238
 239         /* Activate watchdog warning interrupt */
 240         setup_irq(IRQ_WATCHDOG, &p2001_wdt_irq);
 241
 242         /* Activate watchdog */
 243         P2001_TIMER->Timer12_PreDiv &= ~(1<<30);        // WatchDog_Disable
 244 }
 245 #endif
 246
 247
 248 /**************************************************************************
 249  * Main init
 250  **************************************************************************/
 251 static void __init p2001_init_time(void)
 252 {
 253         /*
 254          * disable and clear timer 0, set to
 255          * internal clock and interval mode
 256          */
 257         P2001_TIMER->Timer12_PreDiv = 0x70bb0000;
 258         P2001_TIMER->Timer1 = 0;
 259         P2001_TIMER->Timer2 = 0;
 260
 261         p2001_timer1_init();
 262 #ifdef CONFIG_P2001_TIMER2_LED_FREQ_INDICATOR
 263         p2001_timer2_init();
 264 #endif
 265 #ifdef CONFIG_P2001_WATCHDOG
 266         p2001_wdt_init();
 267 #endif
 268 }
 269
 270 struct sys_timer p2001_timer = {
 271         .init   = p2001_init_time,
 272         .offset = p2001_gettimeoffset,
 273 };