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Diffstat (limited to 'src/drivers/pc80/i8259.c')
| -rw-r--r-- | src/drivers/pc80/i8259.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/drivers/pc80/i8259.c b/src/drivers/pc80/i8259.c new file mode 100644 index 0000000000..66988753cf --- /dev/null +++ b/src/drivers/pc80/i8259.c @@ -0,0 +1,141 @@ +/* + * 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 +} + + |