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2008-08-07 Christian Franke <franke@computer.org>

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* kern/i386/pit.c (TIMER2_SPEAKER): New define.
	(TIMER2_GATE): Likewise.
	(grub_pit_wait): Add enable/disable of the timer2 gate
	bit of port 0x61.  This fixes a possible infinite loop.
This commit is contained in:
chrfranke 2008-08-07 19:43:36 +00:00
parent 5ebc275d6f
commit 5c41d44d7d
2 changed files with 23 additions and 0 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2008-08-07 Christian Franke <franke@computer.org>
* kern/i386/pit.c (TIMER2_SPEAKER): New define.
(TIMER2_GATE): Likewise.
(grub_pit_wait): Add enable/disable of the timer2 gate
bit of port 0x61. This fixes a possible infinite loop.
2008-08-07 Bean <bean123ch@gmail.com> 2008-08-07 Bean <bean123ch@gmail.com>
* conf/x86_64-efi.rmk (kernel_mod_SOURCES): Add kern/time.c, * conf/x86_64-efi.rmk (kernel_mod_SOURCES): Add kern/time.c,

16
kern/i386/pit.c
View file

@ -28,13 +28,29 @@
#define TIMER_ENABLE_LSB 0x20 #define TIMER_ENABLE_LSB 0x20
#define TIMER_ENABLE_MSB 0x10 #define TIMER_ENABLE_MSB 0x10
#define TIMER2_LATCH 0x20 #define TIMER2_LATCH 0x20
#define TIMER2_SPEAKER 0x02
#define TIMER2_GATE 0x01
void void
grub_pit_wait (grub_uint16_t tics) grub_pit_wait (grub_uint16_t tics)
{ {
/* Disable timer2 gate and speaker. */
grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE),
TIMER2_REG_LATCH);
/* Set tics. */
grub_outb (TIMER2_SELECT | TIMER_ENABLE_LSB | TIMER_ENABLE_MSB, TIMER_REG_COMMAND); grub_outb (TIMER2_SELECT | TIMER_ENABLE_LSB | TIMER_ENABLE_MSB, TIMER_REG_COMMAND);
grub_outb (tics & 0xff, TIMER2_REG_CONTROL); grub_outb (tics & 0xff, TIMER2_REG_CONTROL);
grub_outb (tics >> 8, TIMER2_REG_CONTROL); grub_outb (tics >> 8, TIMER2_REG_CONTROL);
/* Enable timer2 gate, keep speaker disabled. */
grub_outb ((grub_inb (TIMER2_REG_LATCH) & ~ TIMER2_SPEAKER) | TIMER2_GATE,
TIMER2_REG_LATCH);
/* Wait. */
while ((grub_inb (TIMER2_REG_LATCH) & TIMER2_LATCH) == 0x00); while ((grub_inb (TIMER2_REG_LATCH) & TIMER2_LATCH) == 0x00);
/* Disable timer2 gate and speaker. */
grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE),
TIMER2_REG_LATCH);
} }