WebSVN – HelenOS – Diff – //branches/rcu/kernel/arch/ia32/src/drivers/i8254.c

 /*
  * Copyright (c) 2001-2004 Jakub Jermar
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /** @addtogroup ia32
  * @{
  */
 /**
  * @file
  * @brief   i8254 chip driver.
  *
  * Low level time functions.
  */
 #include <arch/types.h>
 #include <time/clock.h>
 #include <time/delay.h>
 #include <arch/cycle.h>
 #include <arch/interrupt.h>
 #include <arch/drivers/i8259.h>
 #include <arch/drivers/i8254.h>
 #include <cpu.h>
 #include <config.h>
 #include <arch/pm.h>
 #include <arch/asm.h>
 #include <arch/cpuid.h>
 #include <arch.h>
 #include <time/delay.h>
 #include <ddi/irq.h>
 #include <ddi/device.h>
 #define CLK_PORT1   0x40
 #define CLK_PORT4   0x43
 #define CLK_CONST   1193180
 #define MAGIC_NUMBER    1194
 static irq_t i8254_irq;
 static irq_ownership_t i8254_claim(void)
 {
     return IRQ_ACCEPT;
 }
 static void i8254_irq_handler(irq_t *irq, void *arg, ...)
 {
     /*
      * This IRQ is responsible for kernel preemption.
      * Nevertheless, we are now holding a spinlock which prevents
      * preemption. For this particular IRQ, we don't need the
      * lock. We just release it, call clock() and then reacquire it again.
      */
     spinlock_unlock(&irq->lock);
     clock();
     spinlock_lock(&irq->lock);
 }
 void i8254_init(void)
 {
     irq_initialize(&i8254_irq);
-    i8254_irq.devno = device_assign_devno();
+    i8254_irq.preack = true;
-    i8254_irq.inr = IRQ_CLK;
+    i8254_irq.devno = device_assign_devno();
-    i8254_irq.claim = i8254_claim;
+    i8254_irq.inr = IRQ_CLK;
-    i8254_irq.handler = i8254_irq_handler;
+    i8254_irq.claim = i8254_claim;
-    irq_register(&i8254_irq);
+    i8254_irq.handler = i8254_irq_handler;
+    irq_register(&i8254_irq);
-    i8254_normal_operation();
-}
+    i8254_normal_operation();
+}
-void i8254_normal_operation(void)
-{
+void i8254_normal_operation(void)
-    outb(CLK_PORT4, 0x36);
+{
-    pic_disable_irqs(1 << IRQ_CLK);
+    outb(CLK_PORT4, 0x36);
-    outb(CLK_PORT1, (CLK_CONST / HZ) & 0xf);
+    pic_disable_irqs(1 << IRQ_CLK);
-    outb(CLK_PORT1, (CLK_CONST / HZ) >> 8);
+    outb(CLK_PORT1, (CLK_CONST / HZ) & 0xf);
-    pic_enable_irqs(1 << IRQ_CLK);
+    outb(CLK_PORT1, (CLK_CONST / HZ) >> 8);
-}
+    pic_enable_irqs(1 << IRQ_CLK);
+}
-#define LOOPS 150000
-#define SHIFT 11
+#define LOOPS 150000
-void i8254_calibrate_delay_loop(void)
+#define SHIFT 11
-{
+void i8254_calibrate_delay_loop(void)
-    uint64_t clk1, clk2;
+{
-    uint32_t t1, t2, o1, o2;
+    uint64_t clk1, clk2;
-    uint8_t not_ok;
+    uint32_t t1, t2, o1, o2;
+    uint8_t not_ok;
-    /*
-     * One-shot timer. Count-down from 0xffff at 1193180Hz
+    /*
-     * MAGIC_NUMBER is the magic value for 1ms.
+     * One-shot timer. Count-down from 0xffff at 1193180Hz
-     */
+     * MAGIC_NUMBER is the magic value for 1ms.
-    outb(CLK_PORT4, 0x30);
+     */
-    outb(CLK_PORT1, 0xff);
+    outb(CLK_PORT4, 0x30);
     outb(CLK_PORT1, 0xff);
+    outb(CLK_PORT1, 0xff);
-    do {
-        /* will read both status and count */
+    do {
-        outb(CLK_PORT4, 0xc2);
+        /* will read both status and count */
-        not_ok = (inb(CLK_PORT1)>>6)&1;
+        outb(CLK_PORT4, 0xc2);
-        t1 = inb(CLK_PORT1);
+        not_ok = (inb(CLK_PORT1)>>6)&1;
-        t1 |= inb(CLK_PORT1) << 8;
+        t1 = inb(CLK_PORT1);
-    } while (not_ok);
+        t1 |= inb(CLK_PORT1) << 8;
+    } while (not_ok);
-    asm_delay_loop(LOOPS);
+    asm_delay_loop(LOOPS);
-    outb(CLK_PORT4, 0xd2);
-    t2 = inb(CLK_PORT1);
+    outb(CLK_PORT4, 0xd2);
-    t2 |= inb(CLK_PORT1) << 8;
+    t2 = inb(CLK_PORT1);
+    t2 |= inb(CLK_PORT1) << 8;
-    /*
-     * We want to determine the overhead of the calibrating mechanism.
+    /*
-     */
+     * We want to determine the overhead of the calibrating mechanism.
-    outb(CLK_PORT4, 0xd2);
+     */
-    o1 = inb(CLK_PORT1);
+    outb(CLK_PORT4, 0xd2);
-    o1 |= inb(CLK_PORT1) << 8;
+    o1 = inb(CLK_PORT1);
+    o1 |= inb(CLK_PORT1) << 8;
-    asm_fake_loop(LOOPS);
+    asm_fake_loop(LOOPS);
-    outb(CLK_PORT4, 0xd2);
-    o2 = inb(CLK_PORT1);
+    outb(CLK_PORT4, 0xd2);
-    o2 |= inb(CLK_PORT1) << 8;
+    o2 = inb(CLK_PORT1);
+    o2 |= inb(CLK_PORT1) << 8;
-    CPU->delay_loop_const =
-        ((MAGIC_NUMBER * LOOPS) / 1000) / ((t1 - t2) - (o1 - o2)) +
+    CPU->delay_loop_const =
-        (((MAGIC_NUMBER * LOOPS) / 1000) % ((t1 - t2) - (o1 - o2)) ? 1 : 0);
+        ((MAGIC_NUMBER * LOOPS) / 1000) / ((t1 - t2) - (o1 - o2)) +
+        (((MAGIC_NUMBER * LOOPS) / 1000) % ((t1 - t2) - (o1 - o2)) ? 1 : 0);
-    clk1 = get_cycle();
-    delay(1 << SHIFT);
+    clk1 = get_cycle();
-    clk2 = get_cycle();
+    delay(1 << SHIFT);
+    clk2 = get_cycle();
-    CPU->frequency_mhz = (clk2 - clk1) >> SHIFT;
+    CPU->frequency_mhz = (clk2 - clk1) >> SHIFT;
-    return;
-}
+    return;
+}
-/** @}
- */
+/** @}
+ */

Subversion Repositories HelenOS

(root)//branches/rcu/kernel/arch/ia32/src/drivers/i8254.c – Rev 2131 → 2265