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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2009 coresystems GmbH
*
* This program 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; version 2 of the License.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <arch/io.h>
#include <pc80/i8259.h>
#include <console/console.h>
#define MASTER_PIC_ICW1 0x20
#define SLAVE_PIC_ICW1 0xa0
#define ICW_SELECT (1 << 4)
#define OCW_SELECT (0 << 4)
#define ADI (1 << 2)
#define SNGL (1 << 1)
#define IC4 (1 << 0)
#define MASTER_PIC_ICW2 0x21
#define SLAVE_PIC_ICW2 0xa1
#define INT_VECTOR_MASTER 0x20
#define IRQ0 0x00
#define IRQ1 0x01
#define INT_VECTOR_SLAVE 0x28
#define IRQ8 0x00
#define IRQ9 0x01
#define MASTER_PIC_ICW3 0x21
#define CASCADED_PIC (1 << 2)
#define MASTER_PIC_ICW4 0x21
#define SLAVE_PIC_ICW4 0xa1
#define MICROPROCESSOR_MODE (1 << 0)
#define SLAVE_PIC_ICW3 0xa1
#define SLAVE_ID 0x02
#define MASTER_PIC_OCW1 0x21
#define SLAVE_PIC_OCW1 0xa1
#define IRQ2 (1 << 2)
#define ALL_IRQS 0xff
#define ELCR1 0x4d0
#define ELCR2 0x4d1
void setup_i8259(void)
{
/* A write to ICW1 starts the Interrupt Controller Initialization
* Sequence. This implicitly causes the following to happen:
* - Interrupt Mask register is cleared
* - Priority 7 is assigned to IRQ7 input
* - Slave mode address is set to 7
* - Special mask mode is cleared
*
* We send the initialization sequence to both the master and
* slave i8259 controller.
*/
outb(ICW_SELECT|IC4, MASTER_PIC_ICW1);
outb(ICW_SELECT|IC4, SLAVE_PIC_ICW1);
/* Now the interrupt controller expects us to write to ICW2. */
outb(INT_VECTOR_MASTER | IRQ0, MASTER_PIC_ICW2);
outb(INT_VECTOR_SLAVE | IRQ8, SLAVE_PIC_ICW2);
/* Now the interrupt controller expects us to write to ICW3.
*
* The normal scenario is to set up cascading on IRQ2 on the master
* i8259 and assign the slave ID 2 to the slave i8259.
*/
outb(CASCADED_PIC, MASTER_PIC_ICW3);
outb(SLAVE_ID, SLAVE_PIC_ICW3);
/* Now the interrupt controller expects us to write to ICW4.
*
* We switch both i8259 to microprocessor mode because they're
* operating as part of an x86 architecture based chipset
*/
outb(MICROPROCESSOR_MODE, MASTER_PIC_ICW2);
outb(MICROPROCESSOR_MODE, SLAVE_PIC_ICW2);
/* Now clear the interrupts through OCW1.
* First we mask off all interrupts on the slave interrupt controller
* then we mask off all interrupts but interrupt 2 on the master
* controller. This way the cascading stays alife.
*/
outb(ALL_IRQS, SLAVE_PIC_OCW1);
outb(ALL_IRQS & ~IRQ2, MASTER_PIC_OCW1);
}
/**
* @brief Configure IRQ triggering in the i8259 compatible Interrupt Controller.
*
* Switch a certain interrupt to be level / edge triggered.
*
* @param int_num legacy interrupt number (3-7, 9-15)
* @param is_level_triggered 1 for level triggered interrupt, 0 for edge
* triggered interrupt
*/
void i8259_configure_irq_trigger(int int_num, int is_level_triggered)
{
u16 int_bits = inb(ELCR1) | (((u16)inb(ELCR2)) << 8);
printk(BIOS_SPEW, "%s: current interrupts are 0x%x\n", __func__, int_bits);
if (is_level_triggered)
int_bits |= (1 << int_num);
else
int_bits &= ~(1 << int_num);
/* Write new values */
printk(BIOS_SPEW, "%s: try to set interrupts 0x%x\n", __func__, int_bits);
outb((u8)(int_bits & 0xff), ELCR1);
outb((u8)(int_bits >> 8), ELCR2);
#ifdef PARANOID_IRQ_TRIGGERS
/* Try reading back the new values. This seems like an error but is not ... */
if (inb(ELCR1) != (int_bits & 0xff)) {
printk(BIOS_ERR, "%s: lower order bits are wrong: want 0x%x, got 0x%x\n",
__func__, (int_bits & 0xff), inb(ELCR1));
}
if (inb(ELCR2) != (int_bits >> 8)) {
printk(BIOS_ERR, "%s: higher order bits are wrong: want 0x%x, got 0x%x\n",
__func__, (int_bits>>8), inb(ELCR2));
}
#endif
}
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