2 * linux/arch/sh/kernel/irq_maskreg.c
4 * Copyright (C) 2001 A&D Co., Ltd. <http://www.aandd.co.jp>
6 * This file may be copied or modified under the terms of the GNU
7 * General Public License. See linux/COPYING for more information.
9 * Interrupt handling for Simple external interrupt mask register
11 * This is for the machine which have single 16 bit register
12 * for masking external IRQ individually.
13 * Each bit of the register is for masking each interrupt.
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/irq.h>
20 #include <asm/system.h>
22 #include <asm/machvec.h>
24 /* address of external interrupt mask register
25 * address must be set prior to use these (maybe in init_XXX_irq())
26 * XXX : is it better to use .config than specifying it in code? */
27 unsigned short *irq_mask_register = 0;
29 /* forward declaration */
30 static unsigned int startup_maskreg_irq(unsigned int irq);
31 static void shutdown_maskreg_irq(unsigned int irq);
32 static void enable_maskreg_irq(unsigned int irq);
33 static void disable_maskreg_irq(unsigned int irq);
34 static void mask_and_ack_maskreg(unsigned int);
35 static void end_maskreg_irq(unsigned int irq);
37 /* hw_interrupt_type */
38 static struct hw_interrupt_type maskreg_irq_type = {
39 .typename = " Mask Register",
40 .startup = startup_maskreg_irq,
41 .shutdown = shutdown_maskreg_irq,
42 .enable = enable_maskreg_irq,
43 .disable = disable_maskreg_irq,
44 .ack = mask_and_ack_maskreg,
45 .end = end_maskreg_irq
48 /* actual implementatin */
49 static unsigned int startup_maskreg_irq(unsigned int irq)
51 enable_maskreg_irq(irq);
52 return 0; /* never anything pending */
55 static void shutdown_maskreg_irq(unsigned int irq)
57 disable_maskreg_irq(irq);
60 static void disable_maskreg_irq(unsigned int irq)
62 if (irq_mask_register) {
64 unsigned short val, mask = 0x01 << irq;
67 local_irq_save(flags);
68 val = ctrl_inw((unsigned long)irq_mask_register);
70 ctrl_outw(val, (unsigned long)irq_mask_register);
71 local_irq_restore(flags);
75 static void enable_maskreg_irq(unsigned int irq)
77 if (irq_mask_register) {
79 unsigned short val, mask = ~(0x01 << irq);
81 /* Clear "irq"th bit */
82 local_irq_save(flags);
83 val = ctrl_inw((unsigned long)irq_mask_register);
85 ctrl_outw(val, (unsigned long)irq_mask_register);
86 local_irq_restore(flags);
90 static void mask_and_ack_maskreg(unsigned int irq)
92 disable_maskreg_irq(irq);
95 static void end_maskreg_irq(unsigned int irq)
97 if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
98 enable_maskreg_irq(irq);
101 void make_maskreg_irq(unsigned int irq)
103 disable_irq_nosync(irq);
104 irq_desc[irq].chip = &maskreg_irq_type;
105 disable_maskreg_irq(irq);