/*
- * Basic support for controlling the 8259 Programmable Interrupt Controllers.
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
- * Initially written by Michael Brown (mcb30).
- */
-
-#include <etherboot.h>
-#include "pic8259.h"
-#include "old_realmode.h"
-
-/* State of trivial IRQ handler */
-irq_t trivial_irq_installed_on = IRQ_NONE;
-static uint16_t trivial_irq_previous_trigger_count = 0;
-
-/* The actual trivial IRQ handler
+ * 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; either version 2 of the
+ * License, or any later version.
*
- * Note: we depend on the C compiler not realising that we're putting
- * variables in the ".text16" section and therefore not forcing them
- * back to the ".data" section. I don't see any reason to expect this
- * behaviour to change.
+ * 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.
*
- * These must *not* be the first variables to appear in this file; the
- * first variable to appear gets the ".data" directive.
- */
-RM_FRAGMENT(_trivial_irq_handler,
- "pushw %bx\n\t"
- "call 1f\n1:\tpopw %bx\n\t" /* PIC access to variables */
- "incw %cs:(_trivial_irq_trigger_count-1b)(%bx)\n\t"
- "popw %bx\n\t"
- "iret\n\t"
- "\n\t"
- ".globl _trivial_irq_trigger_count\n\t"
- "_trivial_irq_trigger_count: .short 0\n\t"
- "\n\t"
- ".globl _trivial_irq_chain_to\n\t"
- "_trivial_irq_chain_to: .short 0,0\n\t"
- "\n\t"
- ".globl _trivial_irq_chain\n\t"
- "_trivial_irq_chain: .byte 0\n\t"
- );
-extern volatile uint16_t _trivial_irq_trigger_count;
-extern segoff_t _trivial_irq_chain_to;
-extern int8_t _trivial_irq_chain;
-
-/* Current locations of trivial IRQ handler. These will change at
- * runtime when relocation is used; the handler needs to be copied to
- * base memory before being installed.
- */
-void (*trivial_irq_handler)P((void)) = _trivial_irq_handler;
-uint16_t volatile *trivial_irq_trigger_count = &_trivial_irq_trigger_count;
-segoff_t *trivial_irq_chain_to = &_trivial_irq_chain_to;
-uint8_t *trivial_irq_chain = &_trivial_irq_chain;
-
-/* Install a handler for the specified IRQ. Address of previous
- * handler will be stored in previous_handler. Enabled/disabled state
- * of IRQ will be preserved across call, therefore if the handler does
- * chaining, ensure that either (a) IRQ is disabled before call, or
- * (b) previous_handler points directly to the place that the handler
- * picks up its chain-to address.
- */
-
-int install_irq_handler ( irq_t irq, segoff_t *handler,
- uint8_t *previously_enabled,
- segoff_t *previous_handler ) {
- segoff_t *irq_vector = IRQ_VECTOR ( irq );
- *previously_enabled = irq_enabled ( irq );
-
- if ( irq > IRQ_MAX ) {
- DBG ( "Invalid IRQ number %d\n" );
- return 0;
- }
-
- previous_handler->segment = irq_vector->segment;
- previous_handler->offset = irq_vector->offset;
- if ( *previously_enabled ) disable_irq ( irq );
- DBG ( "Installing handler at %hx:%hx for IRQ %d (vector 0000:%hx),"
- " leaving %s\n",
- handler->segment, handler->offset, irq, virt_to_phys(irq_vector),
- ( *previously_enabled ? "enabled" : "disabled" ) );
- DBG ( "...(previous handler at %hx:%hx)\n",
- previous_handler->segment, previous_handler->offset );
- irq_vector->segment = handler->segment;
- irq_vector->offset = handler->offset;
- if ( *previously_enabled ) enable_irq ( irq );
- return 1;
-}
-
-/* Remove handler for the specified IRQ. Routine checks that another
- * handler has not been installed that chains to handler before
- * uninstalling handler. Enabled/disabled state of the IRQ will be
- * restored to that specified by previously_enabled.
- */
-
-int remove_irq_handler ( irq_t irq, segoff_t *handler,
- uint8_t *previously_enabled,
- segoff_t *previous_handler ) {
- segoff_t *irq_vector = IRQ_VECTOR ( irq );
-
- if ( irq > IRQ_MAX ) {
- DBG ( "Invalid IRQ number %d\n" );
- return 0;
- }
- if ( ( irq_vector->segment != handler->segment ) ||
- ( irq_vector->offset != handler->offset ) ) {
- DBG ( "Cannot remove handler for IRQ %d\n" );
- return 0;
- }
-
- DBG ( "Removing handler for IRQ %d\n", irq );
- disable_irq ( irq );
- irq_vector->segment = previous_handler->segment;
- irq_vector->offset = previous_handler->offset;
- if ( *previously_enabled ) enable_irq ( irq );
- return 1;
-}
-
-/* Install the trivial IRQ handler. This routine installs the
- * handler, tests it and enables the IRQ.
- */
-
-int install_trivial_irq_handler ( irq_t irq ) {
- segoff_t trivial_irq_handler_segoff = SEGOFF(trivial_irq_handler);
-
- if ( trivial_irq_installed_on != IRQ_NONE ) {
- DBG ( "Can install trivial IRQ handler only once\n" );
- return 0;
- }
- if ( SEGMENT(trivial_irq_handler) > 0xffff ) {
- DBG ( "Trivial IRQ handler not in base memory\n" );
- return 0;
- }
-
- DBG ( "Installing trivial IRQ handler on IRQ %d\n", irq );
- if ( ! install_irq_handler ( irq, &trivial_irq_handler_segoff,
- trivial_irq_chain,
- trivial_irq_chain_to ) )
- return 0;
- trivial_irq_installed_on = irq;
-
- DBG ( "Testing trivial IRQ handler\n" );
- disable_irq ( irq );
- *trivial_irq_trigger_count = 0;
- trivial_irq_previous_trigger_count = 0;
- fake_irq ( irq );
- if ( ! trivial_irq_triggered ( irq ) ) {
- DBG ( "Installation of trivial IRQ handler failed\n" );
- remove_trivial_irq_handler ( irq );
- return 0;
- }
- /* Send EOI just in case there was a leftover interrupt */
- send_specific_eoi ( irq );
- DBG ( "Trivial IRQ handler installed successfully\n" );
- enable_irq ( irq );
- return 1;
-}
-
-/* Remove the trivial IRQ handler.
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-int remove_trivial_irq_handler ( irq_t irq ) {
- segoff_t trivial_irq_handler_segoff = SEGOFF(trivial_irq_handler);
-
- if ( trivial_irq_installed_on == IRQ_NONE ) return 1;
- if ( irq != trivial_irq_installed_on ) {
- DBG ( "Cannot uninstall trivial IRQ handler from IRQ %d; "
- "is installed on IRQ %d\n", irq,
- trivial_irq_installed_on );
- return 0;
- }
-
- if ( ! remove_irq_handler ( irq, &trivial_irq_handler_segoff,
- trivial_irq_chain,
- trivial_irq_chain_to ) )
- return 0;
+#include <pic8259.h>
- if ( trivial_irq_triggered ( trivial_irq_installed_on ) ) {
- DBG ( "Sending EOI for unwanted trivial IRQ\n" );
- send_specific_eoi ( trivial_irq_installed_on );
- }
-
- trivial_irq_installed_on = IRQ_NONE;
- return 1;
-}
-
-/* Safe method to detect whether or not trivial IRQ has been
- * triggered. Using this call avoids potential race conditions. This
- * call will return success only once per trigger.
- */
-
-int trivial_irq_triggered ( irq_t irq ) {
- uint16_t trivial_irq_this_trigger_count = *trivial_irq_trigger_count;
- int triggered = ( trivial_irq_this_trigger_count -
- trivial_irq_previous_trigger_count );
-
- /* irq is not used at present, but we have it in the API for
- * future-proofing; in case we want the facility to have
- * multiple trivial IRQ handlers installed simultaneously.
- *
- * Avoid compiler warning about unused variable.
- */
- if ( irq == IRQ_NONE ) {};
-
- trivial_irq_previous_trigger_count = trivial_irq_this_trigger_count;
- return triggered ? 1 : 0;
-}
-
-/* Copy trivial IRQ handler to a new location. Typically used to copy
- * the handler into base memory; when relocation is being used we need
- * to do this before installing the handler.
+/** @file
+ *
+ * Minimal support for the 8259 Programmable Interrupt Controller
*
- * Call with target=NULL in order to restore the handler to its
- * original location.
*/
-int copy_trivial_irq_handler ( void *target, size_t target_size ) {
- irq_t currently_installed_on = trivial_irq_installed_on;
- uint32_t offset = ( target == NULL ? 0 :
- target - (void*)_trivial_irq_handler );
-
- if (( target != NULL ) && ( target_size < TRIVIAL_IRQ_HANDLER_SIZE )) {
- DBG ( "Insufficient space to copy trivial IRQ handler\n" );
- return 0;
- }
-
- if ( currently_installed_on != IRQ_NONE ) {
- DBG ("WARNING: relocating trivial IRQ handler while in use\n");
- if ( ! remove_trivial_irq_handler ( currently_installed_on ) )
- return 0;
- }
-
- /* Do the actual copy */
- if ( target != NULL ) {
- DBG ( "Copying trivial IRQ handler to %hx:%hx\n",
- SEGMENT(target), OFFSET(target) );
- memcpy ( target, _trivial_irq_handler,
- TRIVIAL_IRQ_HANDLER_SIZE );
- } else {
- DBG ( "Restoring trivial IRQ handler to original location\n" );
- }
- /* Update all the pointers to structures within the handler */
- trivial_irq_handler = ( void (*)P((void)) )
- ( (void*)_trivial_irq_handler + offset );
- trivial_irq_trigger_count = (uint16_t*)
- ( (void*)&_trivial_irq_trigger_count + offset );
- trivial_irq_chain_to = (segoff_t*)
- ( (void*)&_trivial_irq_chain_to + offset );
- trivial_irq_chain = (uint8_t*)
- ( (void*)&_trivial_irq_chain + offset );
-
- if ( currently_installed_on != IRQ_NONE ) {
- if ( ! install_trivial_irq_handler ( currently_installed_on ) )
- return 0;
- }
- return 1;
-}
-
-/* Send non-specific EOI(s). This seems to be inherently unsafe.
+/**
+ * Send non-specific EOI(s)
+ *
+ * @v irq IRQ number
+ *
+ * This seems to be inherently unsafe.
*/
-
-void send_nonspecific_eoi ( irq_t irq ) {
+static inline void send_nonspecific_eoi ( unsigned int irq ) {
DBG ( "Sending non-specific EOI for IRQ %d\n", irq );
if ( irq >= IRQ_PIC_CUTOFF ) {
outb ( ICR_EOI_NON_SPECIFIC, PIC2_ICR );
outb ( ICR_EOI_NON_SPECIFIC, PIC1_ICR );
}
-/* Send specific EOI(s).
+/**
+ * Send specific EOI(s)
+ *
+ * @v irq IRQ number
*/
-
-void send_specific_eoi ( irq_t irq ) {
+static inline void send_specific_eoi ( unsigned int irq ) {
DBG ( "Sending specific EOI for IRQ %d\n", irq );
- outb ( ICR_EOI_SPECIFIC | ICR_VALUE(irq), ICR_REG(irq) );
+ outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( irq ) ), ICR_REG ( irq ) );
if ( irq >= IRQ_PIC_CUTOFF ) {
- outb ( ICR_EOI_SPECIFIC | ICR_VALUE(CHAINED_IRQ),
- ICR_REG(CHAINED_IRQ) );
+ outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( CHAINED_IRQ ) ),
+ ICR_REG ( CHAINED_IRQ ) );
}
}
-/* Fake an IRQ
- */
-
-void fake_irq ( irq_t irq ) {
- struct {
- uint16_t int_number;
- } PACKED in_stack;
-
- /* Convert IRQ to INT number:
- *
- * subb $0x08,%cl Invert bit 3, set bits 4-7 iff irq < 8
- * xorb $0x70,%cl Invert bits 4-6
- * andb $0x7f,%cl Clear bit 7
- *
- * No, it's not the most intuitive method, but I was proud to
- * get it down to three lines of assembler when this routine
- * was originally implemented in pcbios.S.
- */
- in_stack.int_number = ( ( irq - 8 ) ^ 0x70 ) & 0x7f;
-
- RM_FRAGMENT(rm_fake_irq,
- "popw %ax\n\t" /* %ax = INT number */
- "call 1f\n1:\tpop %bx\n\t"
- "movb %al, %cs:(2f-1b+1)(%bx)\n\t" /* Overwrite INT number..*/
- "\n2:\tint $0x00\n\t" /* ..in this instruction */
- );
-
- real_call ( rm_fake_irq, &in_stack, NULL );
-}
-
-/* Dump current 8259 status: enabled IRQs and handler addresses.
+/**
+ * Send End-Of-Interrupt to the PIC
+ *
+ * @v irq IRQ number
*/
-
-#ifdef DEBUG_IRQ
-void dump_irq_status ( void ) {
- int irq = 0;
-
- for ( irq = 0; irq < 16; irq++ ) {
- if ( irq_enabled ( irq ) ) {
- printf ( "IRQ%d enabled, ISR at %hx:%hx\n", irq,
- IRQ_VECTOR(irq)->segment,
- IRQ_VECTOR(irq)->offset );
- }
- }
+void send_eoi ( unsigned int irq ) {
+ send_specific_eoi ( irq );
}
-#endif
/* For segoff_t */
#include "realmode.h"
-#define IRQ_PIC_CUTOFF (8)
+#define IRQ_PIC_CUTOFF 8
/* 8259 register locations */
-#define PIC1_ICW1 (0x20)
-#define PIC1_OCW2 (0x20)
-#define PIC1_OCW3 (0x20)
-#define PIC1_ICR (0x20)
-#define PIC1_IRR (0x20)
-#define PIC1_ISR (0x20)
-#define PIC1_ICW2 (0x21)
-#define PIC1_ICW3 (0x21)
-#define PIC1_ICW4 (0x21)
-#define PIC1_IMR (0x21)
-#define PIC2_ICW1 (0xa0)
-#define PIC2_OCW2 (0xa0)
-#define PIC2_OCW3 (0xa0)
-#define PIC2_ICR (0xa0)
-#define PIC2_IRR (0xa0)
-#define PIC2_ISR (0xa0)
-#define PIC2_ICW2 (0xa1)
-#define PIC2_ICW3 (0xa1)
-#define PIC2_ICW4 (0xa1)
-#define PIC2_IMR (0xa1)
+#define PIC1_ICW1 0x20
+#define PIC1_OCW2 0x20
+#define PIC1_OCW3 0x20
+#define PIC1_ICR 0x20
+#define PIC1_IRR 0x20
+#define PIC1_ISR 0x20
+#define PIC1_ICW2 0x21
+#define PIC1_ICW3 0x21
+#define PIC1_ICW4 0x21
+#define PIC1_IMR 0x21
+#define PIC2_ICW1 0xa0
+#define PIC2_OCW2 0xa0
+#define PIC2_OCW3 0xa0
+#define PIC2_ICR 0xa0
+#define PIC2_IRR 0xa0
+#define PIC2_ISR 0xa0
+#define PIC2_ICW2 0xa1
+#define PIC2_ICW3 0xa1
+#define PIC2_ICW4 0xa1
+#define PIC2_IMR 0xa1
/* Register command values */
-#define OCW3_ID (0x08)
-#define OCW3_READ_IRR (0x03)
-#define OCW3_READ_ISR (0x02)
-#define ICR_EOI_NON_SPECIFIC (0x20)
-#define ICR_EOI_NOP (0x40)
-#define ICR_EOI_SPECIFIC (0x60)
-#define ICR_EOI_SET_PRIORITY (0xc0)
+#define OCW3_ID 0x08
+#define OCW3_READ_IRR 0x03
+#define OCW3_READ_ISR 0x02
+#define ICR_EOI_NON_SPECIFIC 0x20
+#define ICR_EOI_NOP 0x40
+#define ICR_EOI_SPECIFIC 0x60
+#define ICR_EOI_SET_PRIORITY 0xc0
/* Macros to enable/disable IRQs */
#define IMR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_IMR : PIC2_IMR )
#define disable_irq(x) outb ( inb( IMR_REG(x) ) | IMR_BIT(x), IMR_REG(x) )
/* Macros for acknowledging IRQs */
-#define ICR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
-#define ICR_VALUE(x) ( (x) % IRQ_PIC_CUTOFF )
+#define ICR_REG( irq ) ( (irq) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
+#define ICR_VALUE( irq ) ( (irq) % IRQ_PIC_CUTOFF )
#define CHAINED_IRQ 2
/* Utility macros to convert IRQ numbers to INT numbers and INT vectors */
-#define IRQ_INT(x) ( (x)<IRQ_PIC_CUTOFF ? (x)+0x08 : (x)-IRQ_PIC_CUTOFF+0x70 )
-#define INT_VECTOR(x) ( (segoff_t*) phys_to_virt( 4 * (x) ) )
-#define IRQ_VECTOR(x) ( INT_VECTOR ( IRQ_INT(x) ) )
+#define IRQ_INT( irq ) ( ( ( (irq) - IRQ_PIC_CUTOFF ) ^ 0x70 ) & 0x7f )
/* Other constants */
-typedef uint8_t irq_t;
-#define IRQ_MAX (15)
-#define IRQ_NONE (0xff)
+#define IRQ_MAX 15
+#define IRQ_NONE -1U
/* Function prototypes
*/
-int install_irq_handler ( irq_t irq, segoff_t *handler,
- uint8_t *previously_enabled,
- segoff_t *previous_handler );
-int remove_irq_handler ( irq_t irq, segoff_t *handler,
- uint8_t *previously_enabled,
- segoff_t *previous_handler );
-int install_trivial_irq_handler ( irq_t irq );
-int remove_trivial_irq_handler ( irq_t irq );
-int trivial_irq_triggered ( irq_t irq );
-int copy_trivial_irq_handler ( void *target, size_t target_size );
-void send_non_specific_eoi ( irq_t irq );
-void send_specific_eoi ( irq_t irq );
-void fake_irq ( irq_t irq );
-#ifdef DEBUG_IRQ
-void dump_irq_status ( void );
-#else
-#define dump_irq_status()
-#endif
-
-/* Other code (e.g. undi.c) needs to know the size of the trivial IRQ
- * handler code, so we put prototypes and the size macro here.
- */
-extern void _trivial_irq_handler ( void );
-extern char _trivial_irq_handler_size[];
-#define TRIVIAL_IRQ_HANDLER_SIZE FRAGMENT_SIZE(_trivial_irq_handler)
+void send_eoi ( unsigned int irq );
#endif /* PIC8259_H */
http://git.etherboot.org / people / xl0 / gpxe.git / commitdiff