1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * arch/sh/kernel/cpu/irq/imask.c
4  *
5  * Copyright (C) 1999, 2000  Niibe Yutaka
6  *
7  * Simple interrupt handling using IMASK of SR register.
8  *
9  */
10 /* NOTE: Will not work on level 15 */
11 #include <linux/ptrace.h>
12 #include <linux/errno.h>
13 #include <linux/kernel_stat.h>
14 #include <linux/signal.h>
15 #include <linux/sched.h>
16 #include <linux/interrupt.h>
17 #include <linux/init.h>
18 #include <linux/bitops.h>
19 #include <linux/spinlock.h>
20 #include <linux/cache.h>
21 #include <linux/irq.h>
22 #include <linux/bitmap.h>
23 #include <asm/irq.h>
24 
25 /* Bitmap of IRQ masked */
26 #define IMASK_PRIORITY	15
27 
28 static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
29 static int interrupt_priority;
30 
set_interrupt_registers(int ip)31 static inline void set_interrupt_registers(int ip)
32 {
33 	unsigned long __dummy;
34 
35 	asm volatile(
36 #ifdef CONFIG_CPU_HAS_SR_RB
37 		     "ldc	%2, r6_bank\n\t"
38 #endif
39 		     "stc	sr, %0\n\t"
40 		     "and	#0xf0, %0\n\t"
41 		     "shlr2	%0\n\t"
42 		     "cmp/eq	#0x3c, %0\n\t"
43 		     "bt/s	1f	! CLI-ed\n\t"
44 		     " stc	sr, %0\n\t"
45 		     "and	%1, %0\n\t"
46 		     "or	%2, %0\n\t"
47 		     "ldc	%0, sr\n"
48 		     "1:"
49 		     : "=&z" (__dummy)
50 		     : "r" (~0xf0), "r" (ip << 4)
51 		     : "t");
52 }
53 
mask_imask_irq(struct irq_data * data)54 static void mask_imask_irq(struct irq_data *data)
55 {
56 	unsigned int irq = data->irq;
57 
58 	clear_bit(irq, imask_mask);
59 	if (interrupt_priority < IMASK_PRIORITY - irq)
60 		interrupt_priority = IMASK_PRIORITY - irq;
61 	set_interrupt_registers(interrupt_priority);
62 }
63 
unmask_imask_irq(struct irq_data * data)64 static void unmask_imask_irq(struct irq_data *data)
65 {
66 	unsigned int irq = data->irq;
67 
68 	set_bit(irq, imask_mask);
69 	interrupt_priority = IMASK_PRIORITY -
70 		find_first_zero_bit(imask_mask, IMASK_PRIORITY);
71 	set_interrupt_registers(interrupt_priority);
72 }
73 
74 static struct irq_chip imask_irq_chip = {
75 	.name		= "SR.IMASK",
76 	.irq_mask	= mask_imask_irq,
77 	.irq_unmask	= unmask_imask_irq,
78 	.irq_mask_ack	= mask_imask_irq,
79 };
80 
make_imask_irq(unsigned int irq)81 void make_imask_irq(unsigned int irq)
82 {
83 	irq_set_chip_and_handler_name(irq, &imask_irq_chip, handle_level_irq,
84 				      "level");
85 }
86