Rewrite i386 interrupt handling

Rewrite interrupt handling functionality for the i386 port. Separated
functionality into separate CPU and Architecture components.

It appears as if the i386 interrupt handler functionality was intended
to allow multiple handlers to be installed for a given interrupt.
Unfortunately, this functionality was not fully implemented and also
had the problem that irq_free_handler() does not allow the passing
of the handler function pointer and therefore could never be used to
free specific handlers that had been installed for a given IRQ.

There were also various issues with array bounds not being fully
tested.

I had two objectives in mind for the new implementation:

1) Keep the implementation as similar as possible to existing
   implementations. To that end, I have used the leon2/3
   implementations as the reference

2) Seperate CPU and Architecture specific elements. All specific i386
   interrupt functionality is now in cpu/i386/ with the high level
   API and architecture specific code in lib_i386. Functionality
   specific to the PC/AT architecture (i.e. cascaded i8259 PICs) has
   been further split out into an individual file to allow for the
   implementation of the PIC architecture of the SC520 CPU (supports
   more IRQs)

Signed-off-by: Graeme Russ <graeme.russ at gmail.com>

5 files changed, 59 insertions, 3 deletions

diff --git a/include/asm-i386/interrupt.h b/include/asm-i386/interrupt.h
index 315b400..7f408cb 100644
--- a/include/asm-i386/interrupt.h
+++ b/include/asm-i386/interrupt.h
@@ -1,7 +1,10 @@
 /*
- * (C) Copyright 2008
+ * (C) Copyright 2009
  * Graeme Russ, graeme.russ@gmail.com
  *
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, daniel@omicron.se
+ *
  * See file CREDITS for list of people who contributed to this
  * project.
  *
@@ -24,6 +27,47 @@
 #ifndef __ASM_INTERRUPT_H_
 #define __ASM_INTERRUPT_H_ 1
 
-void set_vector(int intnum, void *routine);
+/* cpu/i386/interrupts.c */
+void set_vector(u8 intnum, void *routine);
+
+/* lib_i386/interupts.c */
+void disable_irq(int irq);
+void enable_irq(int irq);
+
+/* Architecture specific functions */
+void mask_irq(int irq);
+void unmask_irq(int irq);
+void specific_eoi(int irq);
+
+extern char exception_stack[];
+
+#define __isr__ void __attribute__ ((regparm(0)))
+
+#define DECLARE_INTERRUPT(x) \
+	asm(".globl irq_"#x"\n" \
+		    "irq_"#x":\n" \
+		    "pusha \n" \
+		    "pushl $"#x"\n" \
+		    "pushl $irq_return\n" \
+		    "jmp   do_irq\n"); \
+	__isr__ irq_##x(void)
+
+#define DECLARE_EXCEPTION(x, f) \
+	asm(".globl exp_"#x"\n" \
+		    "exp_"#x":\n" \
+		    "pusha \n" \
+		    "movl     %esp, %ebx\n" \
+		    "movl     $exception_stack, %eax\n" \
+		    "movl     %eax, %esp \n" \
+		    "pushl    %ebx\n" \
+		    "movl     32(%esp), %ebx\n" \
+		    "xorl     %edx, %edx\n" \
+		    "movw     36(%esp), %dx\n" \
+		    "pushl    %edx\n" \
+		    "pushl    %ebx\n" \
+		    "pushl    $"#x"\n" \
+		    "pushl    $exp_return\n" \
+		    "jmp      "#f"\n"); \
+	__isr__ exp_##x(void)
 
 #endif
diff --git a/include/asm-i386/u-boot-i386.h b/include/asm-i386/u-boot-i386.h
index 12d10a7..9a60cac 100644
--- a/include/asm-i386/u-boot-i386.h
+++ b/include/asm-i386/u-boot-i386.h
@@ -45,6 +45,12 @@ extern ulong i386boot_bios_size;    /* size of BIOS emulation code */
 int cpu_init(void);
 int timer_init(void);
 
+/* cpu/.../interrupts.c */
+int cpu_init_interrupts(void);
+
+/* cpu/.../exceptions.c */
+int cpu_init_exceptions(void);
+
 /* board/.../... */
 int board_init(void);
 int dram_init(void);
diff --git a/include/configs/eNET.h b/include/configs/eNET.h
index 2ae79d8..84e1aef 100644
--- a/include/configs/eNET.h
+++ b/include/configs/eNET.h
@@ -90,7 +90,7 @@
 #define CONFIG_CMD_RUN		/* run command in env variable	*/
 #define CONFIG_CMD_SETGETDCR	/* DCR support on 4xx		*/
 #define CONFIG_CMD_XIMG		/* Load part of Multi Image	*/
-#undef CONFIG_CMD_IRQ		/* IRQ Information		*/
+#define CONFIG_CMD_IRQ		/* IRQ Information		*/
 
 #define CONFIG_BOOTDELAY		15
 #define CONFIG_BOOTARGS			"root=/dev/mtdblock0 console=ttyS0,9600"
@@ -148,6 +148,8 @@
 #undef  CONFIG_SYS_TSC_TIMER			/* use the Pentium TSC timers */
 #define CONFIG_SYS_USE_SIO_UART		0       /* prefer the uarts on the SIO to those
 					 * in the SC520 on the CDP */
+#define CONFIG_SYS_PCAT_INTERRUPTS
+#define CONFIG_SYS_NUM_IRQS		16
 
 /*-----------------------------------------------------------------------
  * Memory organization
diff --git a/include/configs/sc520_cdp.h b/include/configs/sc520_cdp.h
index cb0de42..19e5889 100644
--- a/include/configs/sc520_cdp.h
+++ b/include/configs/sc520_cdp.h
@@ -53,6 +53,8 @@
 #undef  CONFIG_SYS_TSC_TIMER                   /* use the Pentium TSC timers */
 #define  CONFIG_SYS_USE_SIO_UART       0       /* prefer the uarts on the SIO to those
 					 * in the SC520 on the CDP */
+#define CONFIG_SYS_PCAT_INTERRUPTS
+#define CONFIG_SYS_NUM_IRQS		16
 
 #define CONFIG_SYS_STACK_SIZE          0x8000  /* Size of bootloader stack */
 
diff --git a/include/configs/sc520_spunk.h b/include/configs/sc520_spunk.h
index 3e86184..20481bd 100644
--- a/include/configs/sc520_spunk.h
+++ b/include/configs/sc520_spunk.h
@@ -49,6 +49,8 @@
 #undef  CONFIG_SYS_SC520_TIMER                 /* use SC520 swtimers */
 #define CONFIG_SYS_GENERIC_TIMER       1       /* use the i8254 PIT timers */
 #undef  CONFIG_SYS_TSC_TIMER                   /* use the Pentium TSC timers */
+#define CONFIG_SYS_PCAT_INTERRUPTS
+#define CONFIG_SYS_NUM_IRQS		16
 
 #define CONFIG_SYS_STACK_SIZE          0x8000  /* Size of bootloader stack */