diff options
Diffstat (limited to 'include/grub/i386/pit.h')
| -rw-r--r-- | include/grub/i386/pit.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/include/grub/i386/pit.h b/include/grub/i386/pit.h new file mode 100644 index 0000000..4bd49d4 --- /dev/null +++ b/include/grub/i386/pit.h @@ -0,0 +1,103 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2008 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef KERNEL_CPU_PIT_HEADER +#define KERNEL_CPU_PIT_HEADER 1 + +#include <grub/types.h> +#include <grub/err.h> + +enum + { + /* The PIT channel value ports. You can write to and read from them. + Do not mess with timer 0 or 1. */ + GRUB_PIT_COUNTER_0 = 0x40, + GRUB_PIT_COUNTER_1 = 0x41, + GRUB_PIT_COUNTER_2 = 0x42, + /* The PIT control port. You can only write to it. Do not mess with + timer 0 or 1. */ + GRUB_PIT_CTRL = 0x43, + /* The speaker port. */ + GRUB_PIT_SPEAKER_PORT = 0x61, + }; + + +/* The speaker port. */ +enum + { + /* If 0, follow state of SPEAKER_DATA bit, otherwise enable output + from timer 2. */ + GRUB_PIT_SPK_TMR2 = 0x01, + /* If SPEAKER_TMR2 is not set, this provides direct input into the + speaker. Otherwise, this enables or disables the output from the + timer. */ + GRUB_PIT_SPK_DATA = 0x02, + + GRUB_PIT_SPK_TMR2_LATCH = 0x20 + }; + +/* The PIT control port. You can only write to it. Do not mess with + timer 0 or 1. */ +enum + { + GRUB_PIT_CTRL_SELECT_MASK = 0xc0, + GRUB_PIT_CTRL_SELECT_0 = 0x00, + GRUB_PIT_CTRL_SELECT_1 = 0x40, + GRUB_PIT_CTRL_SELECT_2 = 0x80, + + /* Read and load control. */ + GRUB_PIT_CTRL_READLOAD_MASK= 0x30, + GRUB_PIT_CTRL_COUNTER_LATCH = 0x00, /* Hold timer value until read. */ + GRUB_PIT_CTRL_READLOAD_LSB = 0x10, /* Read/load the LSB. */ + GRUB_PIT_CTRL_READLOAD_MSB = 0x20, /* Read/load the MSB. */ + GRUB_PIT_CTRL_READLOAD_WORD = 0x30, /* Read/load the LSB then the MSB. */ + + /* Mode control. */ + GRUB_PIT_CTRL_MODE_MASK = 0x0e, + /* Interrupt on terminal count. Setting the mode sets output to low. + When counter is set and terminated, output is set to high. */ + GRUB_PIT_CTRL_INTR_ON_TERM = 0x00, + /* Programmable one-shot. When loading counter, output is set to + high. When counter terminated, output is set to low. Can be + triggered again from that point on by setting the gate pin to + high. */ + GRUB_PIT_CTRL_PROGR_ONE_SHOT = 0x02, + + /* Rate generator. Output is low for one period of the counter, and + high for the other. */ + GRUB_PIT_CTRL_RATE_GEN = 0x04, + + /* Square wave generator. Output is low for one half of the period, + and high for the other half. */ + GRUB_PIT_CTRL_SQUAREWAVE_GEN = 0x06, + /* Software triggered strobe. Setting the mode sets output to high. + When counter is set and terminated, output is set to low. */ + GRUB_PIT_CTRL_SOFTSTROBE = 0x08, + + /* Hardware triggered strobe. Like software triggered strobe, but + only starts the counter when the gate pin is set to high. */ + GRUB_PIT_CTRL_HARDSTROBE = 0x0a, + + + /* Count mode. */ + GRUB_PIT_CTRL_COUNT_MASK = 0x01, + GRUB_PIT_CTRL_COUNT_BINARY = 0x00, /* 16-bit binary counter. */ + GRUB_PIT_CTRL_COUNT_BCD = 0x01 /* 4-decade BCD counter. */ + }; + +#endif /* ! KERNEL_CPU_PIT_HEADER */ |