1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2007 by Ralf Baechle
7 * Copyright (C) 2009, 2010 Cavium Networks, Inc.
8 */
9 #include <linux/clocksource.h>
10 #include <linux/export.h>
11 #include <linux/init.h>
12 #include <linux/smp.h>
13
14 #include <asm/cpu-info.h>
15 #include <asm/time.h>
16
17 #include <asm/octeon/octeon.h>
18 #include <asm/octeon/cvmx-ipd-defs.h>
19 #include <asm/octeon/cvmx-mio-defs.h>
20
21 /*
22 * Set the current core's cvmcount counter to the value of the
23 * IPD_CLK_COUNT. We do this on all cores as they are brought
24 * on-line. This allows for a read from a local cpu register to
25 * access a synchronized counter.
26 *
27 * On CPU_CAVIUM_OCTEON2 the IPD_CLK_COUNT is scaled by rdiv/sdiv.
28 */
octeon_init_cvmcount(void)29 void octeon_init_cvmcount(void)
30 {
31 unsigned long flags;
32 unsigned loops = 2;
33 u64 f = 0;
34 u64 rdiv = 0;
35 u64 sdiv = 0;
36 if (current_cpu_type() == CPU_CAVIUM_OCTEON2) {
37 union cvmx_mio_rst_boot rst_boot;
38 rst_boot.u64 = cvmx_read_csr(CVMX_MIO_RST_BOOT);
39 rdiv = rst_boot.s.c_mul; /* CPU clock */
40 sdiv = rst_boot.s.pnr_mul; /* I/O clock */
41 f = (0x8000000000000000ull / sdiv) * 2;
42 }
43
44
45 /* Clobber loops so GCC will not unroll the following while loop. */
46 asm("" : "+r" (loops));
47
48 local_irq_save(flags);
49 /*
50 * Loop several times so we are executing from the cache,
51 * which should give more deterministic timing.
52 */
53 while (loops--) {
54 u64 ipd_clk_count = cvmx_read_csr(CVMX_IPD_CLK_COUNT);
55 if (rdiv != 0) {
56 ipd_clk_count *= rdiv;
57 if (f != 0) {
58 asm("dmultu\t%[cnt],%[f]\n\t"
59 "mfhi\t%[cnt]"
60 : [cnt] "+r" (ipd_clk_count),
61 [f] "=r" (f)
62 : : "hi", "lo");
63 }
64 }
65 write_c0_cvmcount(ipd_clk_count);
66 }
67 local_irq_restore(flags);
68 }
69
octeon_cvmcount_read(struct clocksource * cs)70 static cycle_t octeon_cvmcount_read(struct clocksource *cs)
71 {
72 return read_c0_cvmcount();
73 }
74
75 static struct clocksource clocksource_mips = {
76 .name = "OCTEON_CVMCOUNT",
77 .read = octeon_cvmcount_read,
78 .mask = CLOCKSOURCE_MASK(64),
79 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
80 };
81
sched_clock(void)82 unsigned long long notrace sched_clock(void)
83 {
84 /* 64-bit arithmatic can overflow, so use 128-bit. */
85 u64 t1, t2, t3;
86 unsigned long long rv;
87 u64 mult = clocksource_mips.mult;
88 u64 shift = clocksource_mips.shift;
89 u64 cnt = read_c0_cvmcount();
90
91 asm (
92 "dmultu\t%[cnt],%[mult]\n\t"
93 "nor\t%[t1],$0,%[shift]\n\t"
94 "mfhi\t%[t2]\n\t"
95 "mflo\t%[t3]\n\t"
96 "dsll\t%[t2],%[t2],1\n\t"
97 "dsrlv\t%[rv],%[t3],%[shift]\n\t"
98 "dsllv\t%[t1],%[t2],%[t1]\n\t"
99 "or\t%[rv],%[t1],%[rv]\n\t"
100 : [rv] "=&r" (rv), [t1] "=&r" (t1), [t2] "=&r" (t2), [t3] "=&r" (t3)
101 : [cnt] "r" (cnt), [mult] "r" (mult), [shift] "r" (shift)
102 : "hi", "lo");
103 return rv;
104 }
105
plat_time_init(void)106 void __init plat_time_init(void)
107 {
108 clocksource_mips.rating = 300;
109 clocksource_register_hz(&clocksource_mips, octeon_get_clock_rate());
110 }
111
112 static u64 octeon_udelay_factor;
113 static u64 octeon_ndelay_factor;
114
octeon_setup_delays(void)115 void __init octeon_setup_delays(void)
116 {
117 octeon_udelay_factor = octeon_get_clock_rate() / 1000000;
118 /*
119 * For __ndelay we divide by 2^16, so the factor is multiplied
120 * by the same amount.
121 */
122 octeon_ndelay_factor = (octeon_udelay_factor * 0x10000ull) / 1000ull;
123
124 preset_lpj = octeon_get_clock_rate() / HZ;
125 }
126
__udelay(unsigned long us)127 void __udelay(unsigned long us)
128 {
129 u64 cur, end, inc;
130
131 cur = read_c0_cvmcount();
132
133 inc = us * octeon_udelay_factor;
134 end = cur + inc;
135
136 while (end > cur)
137 cur = read_c0_cvmcount();
138 }
139 EXPORT_SYMBOL(__udelay);
140
__ndelay(unsigned long ns)141 void __ndelay(unsigned long ns)
142 {
143 u64 cur, end, inc;
144
145 cur = read_c0_cvmcount();
146
147 inc = ((ns * octeon_ndelay_factor) >> 16);
148 end = cur + inc;
149
150 while (end > cur)
151 cur = read_c0_cvmcount();
152 }
153 EXPORT_SYMBOL(__ndelay);
154
__delay(unsigned long loops)155 void __delay(unsigned long loops)
156 {
157 u64 cur, end;
158
159 cur = read_c0_cvmcount();
160 end = cur + loops;
161
162 while (end > cur)
163 cur = read_c0_cvmcount();
164 }
165 EXPORT_SYMBOL(__delay);
166