1 /* SPDX-License-Identifier: GPL-2.0
2  *
3  * include/asm-sh/cpu-sh2/watchdog.h
4  *
5  * Copyright (C) 2002, 2003 Paul Mundt
6  */
7 #ifndef __ASM_CPU_SH2_WATCHDOG_H
8 #define __ASM_CPU_SH2_WATCHDOG_H
9 
10 /*
11  * More SH-2 brilliance .. its not good enough that we can't read
12  * and write the same sizes to WTCNT, now we have to read and write
13  * with different sizes at different addresses for WTCNT _and_ RSTCSR.
14  *
15  * At least on the bright side no one has managed to screw over WTCSR
16  * in this fashion .. yet.
17  */
18 /* Register definitions */
19 #define WTCNT		0xfffffe80
20 #define WTCSR		0xfffffe80
21 #define RSTCSR		0xfffffe82
22 
23 #define WTCNT_R		(WTCNT + 1)
24 #define RSTCSR_R	(RSTCSR + 1)
25 
26 /* Bit definitions */
27 #define WTCSR_IOVF	0x80
28 #define WTCSR_WT	0x40
29 #define WTCSR_TME	0x20
30 #define WTCSR_RSTS	0x00
31 
32 #define RSTCSR_RSTS	0x20
33 
34 /**
35  * 	sh_wdt_read_rstcsr - Read from Reset Control/Status Register
36  *
37  *	Reads back the RSTCSR value.
38  */
39 static inline __u8 sh_wdt_read_rstcsr(void)
40 {
41 	/*
42 	 * Same read/write brain-damage as for WTCNT here..
43 	 */
44 	return __raw_readb(RSTCSR_R);
45 }
46 
47 /**
48  * 	sh_wdt_write_csr - Write to Reset Control/Status Register
49  *
50  * 	@val: Value to write
51  *
52  * 	Writes the given value @val to the lower byte of the control/status
53  * 	register. The upper byte is set manually on each write.
54  */
55 static inline void sh_wdt_write_rstcsr(__u8 val)
56 {
57 	/*
58 	 * Note: Due to the brain-damaged nature of this register,
59 	 * we can't presently touch the WOVF bit, since the upper byte
60 	 * has to be swapped for this. So just leave it alone..
61 	 */
62 	__raw_writeb((WTCNT_HIGH << 8) | (__u16)val, RSTCSR);
63 }
64 
65 #endif /* __ASM_CPU_SH2_WATCHDOG_H */
66 
67