1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2000, 2001 Broadcom Corporation
4  *
5  * Copyright (C) 2002 MontaVista Software Inc.
6  * Author: jsun@mvista.com or jsun@junsun.net
7  */
8 #include <linux/bcd.h>
9 #include <linux/types.h>
10 #include <linux/time.h>
11 
12 #include <asm/time.h>
13 #include <asm/addrspace.h>
14 #include <asm/io.h>
15 
16 #include <asm/sibyte/sb1250.h>
17 #include <asm/sibyte/sb1250_regs.h>
18 #include <asm/sibyte/sb1250_smbus.h>
19 
20 
21 /* Xicor 1241 definitions */
22 
23 /*
24  * Register bits
25  */
26 
27 #define X1241REG_SR_BAT 0x80		/* currently on battery power */
28 #define X1241REG_SR_RWEL 0x04		/* r/w latch is enabled, can write RTC */
29 #define X1241REG_SR_WEL 0x02		/* r/w latch is unlocked, can enable r/w now */
30 #define X1241REG_SR_RTCF 0x01		/* clock failed */
31 #define X1241REG_BL_BP2 0x80		/* block protect 2 */
32 #define X1241REG_BL_BP1 0x40		/* block protect 1 */
33 #define X1241REG_BL_BP0 0x20		/* block protect 0 */
34 #define X1241REG_BL_WD1 0x10
35 #define X1241REG_BL_WD0 0x08
36 #define X1241REG_HR_MIL 0x80		/* military time format */
37 
38 /*
39  * Register numbers
40  */
41 
42 #define X1241REG_BL	0x10		/* block protect bits */
43 #define X1241REG_INT	0x11		/*  */
44 #define X1241REG_SC	0x30		/* Seconds */
45 #define X1241REG_MN	0x31		/* Minutes */
46 #define X1241REG_HR	0x32		/* Hours */
47 #define X1241REG_DT	0x33		/* Day of month */
48 #define X1241REG_MO	0x34		/* Month */
49 #define X1241REG_YR	0x35		/* Year */
50 #define X1241REG_DW	0x36		/* Day of Week */
51 #define X1241REG_Y2K	0x37		/* Year 2K */
52 #define X1241REG_SR	0x3F		/* Status register */
53 
54 #define X1241_CCR_ADDRESS	0x6F
55 
56 #define SMB_CSR(reg)	IOADDR(A_SMB_REGISTER(1, reg))
57 
58 static int xicor_read(uint8_t addr)
59 {
60 	while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
61 		;
62 
63 	__raw_writeq((addr >> 8) & 0x7, SMB_CSR(R_SMB_CMD));
64 	__raw_writeq(addr & 0xff, SMB_CSR(R_SMB_DATA));
65 	__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
66 		     SMB_CSR(R_SMB_START));
67 
68 	while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
69 		;
70 
71 	__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
72 		     SMB_CSR(R_SMB_START));
73 
74 	while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
75 		;
76 
77 	if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
78 		/* Clear error bit by writing a 1 */
79 		__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
80 		return -1;
81 	}
82 
83 	return __raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff;
84 }
85 
86 static int xicor_write(uint8_t addr, int b)
87 {
88 	while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
89 		;
90 
91 	__raw_writeq(addr, SMB_CSR(R_SMB_CMD));
92 	__raw_writeq((addr & 0xff) | ((b & 0xff) << 8), SMB_CSR(R_SMB_DATA));
93 	__raw_writeq(V_SMB_ADDR(X1241_CCR_ADDRESS) | V_SMB_TT_WR3BYTE,
94 		     SMB_CSR(R_SMB_START));
95 
96 	while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
97 		;
98 
99 	if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
100 		/* Clear error bit by writing a 1 */
101 		__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
102 		return -1;
103 	} else {
104 		return 0;
105 	}
106 }
107 
108 int xicor_set_time(time64_t t)
109 {
110 	struct rtc_time tm;
111 	int tmp;
112 	unsigned long flags;
113 
114 	rtc_time64_to_tm(t, &tm);
115 	tm.tm_year += 1900;
116 
117 	spin_lock_irqsave(&rtc_lock, flags);
118 	/* unlock writes to the CCR */
119 	xicor_write(X1241REG_SR, X1241REG_SR_WEL);
120 	xicor_write(X1241REG_SR, X1241REG_SR_WEL | X1241REG_SR_RWEL);
121 
122 	/* trivial ones */
123 	tm.tm_sec = bin2bcd(tm.tm_sec);
124 	xicor_write(X1241REG_SC, tm.tm_sec);
125 
126 	tm.tm_min = bin2bcd(tm.tm_min);
127 	xicor_write(X1241REG_MN, tm.tm_min);
128 
129 	tm.tm_mday = bin2bcd(tm.tm_mday);
130 	xicor_write(X1241REG_DT, tm.tm_mday);
131 
132 	/* tm_mon starts from 0, *ick* */
133 	tm.tm_mon ++;
134 	tm.tm_mon = bin2bcd(tm.tm_mon);
135 	xicor_write(X1241REG_MO, tm.tm_mon);
136 
137 	/* year is split */
138 	tmp = tm.tm_year / 100;
139 	tm.tm_year %= 100;
140 	xicor_write(X1241REG_YR, tm.tm_year);
141 	xicor_write(X1241REG_Y2K, tmp);
142 
143 	/* hour is the most tricky one */
144 	tmp = xicor_read(X1241REG_HR);
145 	if (tmp & X1241REG_HR_MIL) {
146 		/* 24 hour format */
147 		tm.tm_hour = bin2bcd(tm.tm_hour);
148 		tmp = (tmp & ~0x3f) | (tm.tm_hour & 0x3f);
149 	} else {
150 		/* 12 hour format, with 0x2 for pm */
151 		tmp = tmp & ~0x3f;
152 		if (tm.tm_hour >= 12) {
153 			tmp |= 0x20;
154 			tm.tm_hour -= 12;
155 		}
156 		tm.tm_hour = bin2bcd(tm.tm_hour);
157 		tmp |= tm.tm_hour;
158 	}
159 	xicor_write(X1241REG_HR, tmp);
160 
161 	xicor_write(X1241REG_SR, 0);
162 	spin_unlock_irqrestore(&rtc_lock, flags);
163 
164 	return 0;
165 }
166 
167 time64_t xicor_get_time(void)
168 {
169 	unsigned int year, mon, day, hour, min, sec, y2k;
170 	unsigned long flags;
171 
172 	spin_lock_irqsave(&rtc_lock, flags);
173 	sec = xicor_read(X1241REG_SC);
174 	min = xicor_read(X1241REG_MN);
175 	hour = xicor_read(X1241REG_HR);
176 
177 	if (hour & X1241REG_HR_MIL) {
178 		hour &= 0x3f;
179 	} else {
180 		if (hour & 0x20)
181 			hour = (hour & 0xf) + 0x12;
182 	}
183 
184 	day = xicor_read(X1241REG_DT);
185 	mon = xicor_read(X1241REG_MO);
186 	year = xicor_read(X1241REG_YR);
187 	y2k = xicor_read(X1241REG_Y2K);
188 	spin_unlock_irqrestore(&rtc_lock, flags);
189 
190 	sec = bcd2bin(sec);
191 	min = bcd2bin(min);
192 	hour = bcd2bin(hour);
193 	day = bcd2bin(day);
194 	mon = bcd2bin(mon);
195 	year = bcd2bin(year);
196 	y2k = bcd2bin(y2k);
197 
198 	year += (y2k * 100);
199 
200 	return mktime64(year, mon, day, hour, min, sec);
201 }
202 
203 int xicor_probe(void)
204 {
205 	return xicor_read(X1241REG_SC) != -1;
206 }
207