patch-2.3.9 linux/arch/mips/baget/irq.c

• Lines: 439
• Date: Fri Jun 25 17:40:12 1999
• Orig file: v2.3.8/linux/arch/mips/baget/irq.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.8/linux/arch/mips/baget/irq.c linux/arch/mips/baget/irq.c
@@ -0,0 +1,438 @@
+/*
+ * Code to handle Baget/MIPS IRQs plus some generic interrupt stuff.
+ *
+ * Copyright (C) 1998 Vladimir Roganov & Gleb Raiko
+ *      Code (mostly sleleton and comments) derived from DECstation IRQ
+ *      handling.
+ *
+ * $Id$
+ */
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/timex.h>
+#include <linux/malloc.h>
+#include <linux/random.h>
+#include <linux/delay.h>
+
+#include <asm/bitops.h>
+#include <asm/bootinfo.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/mipsregs.h>
+#include <asm/system.h>
+
+#include <asm/baget/baget.h>
+
+unsigned int local_bh_count[NR_CPUS];
+unsigned int local_irq_count[NR_CPUS];
+unsigned long spurious_count = 0;
+
+atomic_t __mips_bh_counter;
+
+/*
+ * This table is a correspondence between IRQ numbers and CPU PILs
+ */
+ 
+static int irq_to_pil_map[BAGET_IRQ_NR] = { 
+	7/*fixme: dma_err -1*/,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 0x00 - 0x0f */
+	-1,-1,-1,-1, 3,-1,-1,-1, 2, 2, 2,-1, 3,-1,-1,3/*fixme: lance*/, /* 0x10 - 0x1f */
+        -1,-1,-1,-1,-1,-1, 5,-1,-1,-1,-1,-1, 7,-1,-1,-1, /* 0x20 - 0x2f */
+	-1, 3, 2/*fixme systimer:3*/, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3  /* 0x30 - 0x3f */
+};
+
+static inline int irq_to_pil(int irq_nr) 
+{
+	int pil = -1;
+
+	if (irq_nr >= BAGET_IRQ_NR) 
+		baget_printk("irq_to_pil: too large irq_nr = 0x%x\n", irq_nr);
+	else {
+		pil = irq_to_pil_map[irq_nr];
+		if (pil == -1)
+			baget_printk("irq_to_pil: unknown irq = 0x%x\n", irq_nr);
+	}
+
+	return pil;
+}
+
+/* Function for careful CP0 interrupt mask access */
+
+static inline void modify_cp0_intmask(unsigned clr_mask, unsigned set_mask)
+{
+	unsigned long status = read_32bit_cp0_register(CP0_STATUS);
+	status &= ~((clr_mask & 0xFF) << 8);
+	status |=   (set_mask & 0xFF) << 8;
+	write_32bit_cp0_register(CP0_STATUS, status);
+}
+
+/* 
+ *  These two functions may be used for unconditional IRQ
+ *  masking via their PIL protection.
+ */
+
+static inline void mask_irq(unsigned int irq_nr)
+{
+        modify_cp0_intmask(irq_to_pil(irq_nr), 0);
+}
+
+static inline void unmask_irq(unsigned int irq_nr)
+{
+	modify_cp0_intmask(0, irq_to_pil(irq_nr));
+}
+
+/*
+ * The following section is introduced for masking/unasking IRQ
+ * only while no more IRQs uses same CPU PIL.
+ *
+ * These functions are used in request_irq, free_irq, but it looks
+ * they cannot change something: CP0_STATUS is private for any
+ * process, and their action is invisible for system.
+ */
+
+static volatile unsigned int pil_in_use[BAGET_PIL_NR] = { 0, };
+
+void mask_irq_count(int irq_nr) 
+{
+	unsigned long flags;
+	int pil = irq_to_pil(irq_nr);
+	
+	save_and_cli(flags);
+	if (!--pil_in_use[pil])
+		mask_irq(irq_nr);
+	restore_flags(flags);
+}
+
+void unmask_irq_count(int irq_nr) 
+{
+	unsigned long flags;
+	int pil = irq_to_pil(irq_nr);
+	
+	save_and_cli(flags);
+	if (!pil_in_use[pil]++)
+		unmask_irq(irq_nr);
+	restore_flags(flags);
+}
+
+/*
+ * Two functions below are exported versions of mask/unmask IRQ
+ */
+
+void disable_irq(unsigned int irq_nr)
+{
+	unsigned long flags;
+
+	save_and_cli(flags);
+	mask_irq(irq_nr);
+	restore_flags(flags);
+}
+
+void enable_irq(unsigned int irq_nr)
+{
+	unsigned long flags;
+
+	save_and_cli(flags);
+	unmask_irq(irq_nr);
+	restore_flags(flags);
+}
+
+/*
+ * Data definition for static irqaction allocation.
+ * It is used while SLAB module is not initialized.
+ */
+
+#define MAX_STATIC_ALLOC 4 
+struct irqaction static_irqaction[MAX_STATIC_ALLOC];
+int static_irq_count = 0;
+ 
+/*
+ * Pointers to the low-level handlers: first the general ones, then the
+ * fast ones, then the bad ones.
+ */
+static struct irqaction *irq_action[BAGET_IRQ_NR] = { NULL, };
+
+int get_irq_list(char *buf)
+{
+	int i, len = 0;
+	struct irqaction * action;
+
+	for (i = 0 ; i < BAGET_IRQ_NR ; i++) {
+		action = irq_action[i];
+		if (!action) 
+			continue;
+		len += sprintf(buf+len, "%2d: %8d %c %s",
+			i, kstat.irqs[0][i],
+			(action->flags & SA_INTERRUPT) ? '+' : ' ',
+			action->name);
+		for (action=action->next; action; action = action->next) {
+			len += sprintf(buf+len, ",%s %s",
+				(action->flags & SA_INTERRUPT) ? " +" : "",
+				action->name);
+		}
+		len += sprintf(buf+len, "\n");
+	}
+	return len;
+}
+
+
+/*
+ * do_IRQ handles IRQ's that have been installed without the
+ * SA_INTERRUPT flag: it uses the full signal-handling return
+ * and runs with other interrupts enabled. All relatively slow
+ * IRQ's should use this format: notably the keyboard/timer
+ * routines.
+ */
+static void do_IRQ(int irq, struct pt_regs * regs)
+{
+	struct irqaction *action;
+	int do_random, cpu;
+
+	cpu = smp_processor_id();
+	hardirq_enter(cpu);
+	kstat.irqs[cpu][irq]++;
+
+	mask_irq(irq);  
+	action = *(irq + irq_action);
+	if (action) {
+		if (!(action->flags & SA_INTERRUPT))
+			__sti();
+		action = *(irq + irq_action);
+		do_random = 0;
+        	do {
+			do_random |= action->flags;
+			action->handler(irq, action->dev_id, regs);
+			action = action->next;
+        	} while (action);
+		if (do_random & SA_SAMPLE_RANDOM)
+			add_interrupt_randomness(irq);
+		__cli();
+	} else {
+		printk("do_IRQ: Unregistered IRQ (0x%X) occured\n", irq);
+	}
+	unmask_irq(irq);
+	hardirq_exit(cpu);
+
+	/* unmasking and bottom half handling is done magically for us. */
+}
+
+/*
+ *  What to do in case of 'no VIC register available' for current interrupt
+ */
+static void vic_reg_error(unsigned long address, unsigned char active_pils) 
+{
+	printk("\nNo VIC register found: reg=%08lx active_pils=%02x\n"
+	       "Current interrupt mask from CP0_CAUSE: %02x\n", 
+	       address, 0xff & active_pils, 
+	       0xff & (read_32bit_cp0_register(CP0_CAUSE)>>8));
+	{ int i; for (i=0; i<10000; i++) udelay(1000); }
+}	
+
+static char baget_fpu_irq = BAGET_FPU_IRQ;
+#define BAGET_INT_FPU {(unsigned long)&baget_fpu_irq, 1}
+
+/*
+ *  Main interrupt handler: interrupt demultiplexer
+ */
+asmlinkage void baget_interrupt(struct pt_regs *regs)
+{
+	static struct baget_int_reg int_reg[BAGET_PIL_NR] = { 
+		BAGET_INT_NONE, BAGET_INT_NONE, BAGET_INT0_ACK, BAGET_INT1_ACK,
+		BAGET_INT_NONE, BAGET_INT_FPU,  BAGET_INT_NONE, BAGET_INT5_ACK 
+	};
+	unsigned char active_pils;
+	while ((active_pils = read_32bit_cp0_register(CP0_CAUSE)>>8)) {
+		int pil;
+		struct baget_int_reg* reg;
+
+                for (pil = 0; pil < BAGET_PIL_NR; pil++) {
+                        if (!(active_pils & (1<<pil))) continue;
+ 			
+			reg = &int_reg[pil];
+
+			if (reg->address) {
+                                extern int try_read(unsigned long,int);
+				int irq  = try_read(reg->address, reg->size);
+
+				if (irq != -1) 
+				      do_IRQ(BAGET_IRQ_MASK(irq), regs);
+				else 
+				      vic_reg_error(reg->address, active_pils);
+			} else {
+				printk("baget_interrupt: unknown interrupt "
+				       "(pil = %d)\n", pil);
+			}
+		}
+	}
+}
+
+/*
+ * Idea is to put all interrupts
+ * in a single table and differenciate them just by number.
+ */
+int setup_baget_irq(int irq, struct irqaction * new)
+{
+	int shared = 0;
+	struct irqaction *old, **p;
+	unsigned long flags;
+
+	p = irq_action + irq;
+	if ((old = *p) != NULL) {
+		/* Can't share interrupts unless both agree to */
+		if (!(old->flags & new->flags & SA_SHIRQ))
+			return -EBUSY;
+
+		/* Can't share interrupts unless both are same type */
+		if ((old->flags ^ new->flags) & SA_INTERRUPT)
+			return -EBUSY;
+
+		/* add new interrupt at end of irq queue */
+		do {
+			p = &old->next;
+			old = *p;
+		} while (old);
+		shared = 1;
+	}
+
+	if (new->flags & SA_SAMPLE_RANDOM)
+		rand_initialize_irq(irq);
+
+	save_and_cli(flags);
+	*p = new;
+	restore_flags(flags);
+
+	if (!shared) {
+		unmask_irq_count(irq);
+	}
+
+	return 0;
+}
+
+int request_irq(unsigned int irq, 
+		void (*handler)(int, void *, struct pt_regs *),
+		unsigned long irqflags, 
+		const char * devname,
+		void *dev_id)
+{
+	int retval;
+	struct irqaction * action = NULL;
+
+	if (irq >= BAGET_IRQ_NR)
+		return -EINVAL;
+	if (!handler)
+		return -EINVAL;
+	if (irq_to_pil_map[irq] < 0) 
+		return -EINVAL;
+
+        if (irqflags & SA_STATIC_ALLOC) {
+		unsigned long flags;
+
+		save_and_cli(flags);
+		if (static_irq_count < MAX_STATIC_ALLOC)
+			action = &static_irqaction[static_irq_count++];
+		else 
+			printk("Request for IRQ%d (%s) SA_STATIC_ALLOC failed "
+			       "using kmalloc\n", irq, devname);
+		restore_flags(flags);
+	}
+  
+	if (action == NULL)
+		action = (struct irqaction *)
+			kmalloc(sizeof(struct irqaction), GFP_KERNEL);
+
+	if (!action) 
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->flags = irqflags;
+	action->mask = 0;
+	action->name = devname;
+	action->next = NULL;
+	action->dev_id = dev_id;
+
+	retval = setup_baget_irq(irq, action);
+
+	if (retval)
+		kfree(action);
+
+	return retval;
+}
+		
+void free_irq(unsigned int irq, void *dev_id)
+{
+	struct irqaction * action, **p;
+	unsigned long flags;
+
+	if (irq >= BAGET_IRQ_NR) 
+		printk("Trying to free IRQ%d\n",irq);
+
+	for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {
+		if (action->dev_id != dev_id)
+			continue;
+
+		/* Found it - now free it */
+		save_and_cli(flags);
+		*p = action->next;
+		if (!irq[irq_action])
+			unmask_irq_count(irq);
+		restore_flags(flags);
+
+		if (action->flags & SA_STATIC_ALLOC)
+		{
+			/* This interrupt is marked as specially allocated
+			 * so it is a bad idea to free it.
+			 */
+			printk("Attempt to free statically allocated "
+			       "IRQ%d (%s)\n", irq, action->name);
+			return;
+		}
+ 
+		kfree(action);
+		return;
+	}
+	printk("Trying to free free IRQ%d\n",irq);
+}
+
+static int baget_irq_canonicalize(int irq) 
+{
+	return irq;
+}
+
+int (*irq_cannonicalize)(int irq) = baget_irq_canonicalize; 
+
+unsigned long probe_irq_on (void)
+{
+	/* TODO */
+	return 0;
+}
+
+int probe_irq_off (unsigned long irqs)
+{
+	/* TODO */
+	return 0;
+}
+
+
+static void write_err_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+{
+	*(volatile char*) BAGET_WRERR_ACK = 0;
+}
+
+__initfunc(void init_IRQ(void))
+{
+	irq_setup();
+
+	/* Enable access to VIC interrupt registers */
+	vac_outw(0xacef | 0x8200, VAC_PIO_FUNC);
+
+	/* Enable interrupts for pils 2 and 3 (lines 0 and 1) */
+	modify_cp0_intmask(0, (1<<2)|(1<<3));
+
+	if (request_irq(0/*fixme*/, write_err_interrupt, 
+			SA_INTERRUPT|SA_STATIC_ALLOC, "write_err", NULL) < 0) 
+		printk("init_IRQ: unable to register write_err irq\n");
+}