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/init.h> 11 #include <linux/smp.h> 12 13 #include <asm/cpu-info.h> 14 #include <asm/time.h> 15 16 #include <asm/octeon/octeon.h> 17 #include <asm/octeon/cvmx-ipd-defs.h> 18 #include <asm/octeon/cvmx-mio-defs.h> 19 20 /* 21 * Set the current core's cvmcount counter to the value of the 22 * IPD_CLK_COUNT. We do this on all cores as they are brought 23 * on-line. This allows for a read from a local cpu register to 24 * access a synchronized counter. 25 * 26 * On CPU_CAVIUM_OCTEON2 the IPD_CLK_COUNT is scaled by rdiv/sdiv. 27 */ 28 void octeon_init_cvmcount(void) 29 { 30 unsigned long flags; 31 unsigned loops = 2; 32 u64 f = 0; 33 u64 rdiv = 0; 34 u64 sdiv = 0; 35 if (current_cpu_type() == CPU_CAVIUM_OCTEON2) { 36 union cvmx_mio_rst_boot rst_boot; 37 rst_boot.u64 = cvmx_read_csr(CVMX_MIO_RST_BOOT); 38 rdiv = rst_boot.s.c_mul; /* CPU clock */ 39 sdiv = rst_boot.s.pnr_mul; /* I/O clock */ 40 f = (0x8000000000000000ull / sdiv) * 2; 41 } 42 43 44 /* Clobber loops so GCC will not unroll the following while loop. */ 45 asm("" : "+r" (loops)); 46 47 local_irq_save(flags); 48 /* 49 * Loop several times so we are executing from the cache, 50 * which should give more deterministic timing. 51 */ 52 while (loops--) { 53 u64 ipd_clk_count = cvmx_read_csr(CVMX_IPD_CLK_COUNT); 54 if (rdiv != 0) { 55 ipd_clk_count *= rdiv; 56 if (f != 0) { 57 asm("dmultu\t%[cnt],%[f]\n\t" 58 "mfhi\t%[cnt]" 59 : [cnt] "+r" (ipd_clk_count), 60 [f] "=r" (f) 61 : : "hi", "lo"); 62 } 63 } 64 write_c0_cvmcount(ipd_clk_count); 65 } 66 local_irq_restore(flags); 67 } 68 69 static cycle_t octeon_cvmcount_read(struct clocksource *cs) 70 { 71 return read_c0_cvmcount(); 72 } 73 74 static struct clocksource clocksource_mips = { 75 .name = "OCTEON_CVMCOUNT", 76 .read = octeon_cvmcount_read, 77 .mask = CLOCKSOURCE_MASK(64), 78 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 79 }; 80 81 unsigned long long notrace sched_clock(void) 82 { 83 /* 64-bit arithmatic can overflow, so use 128-bit. */ 84 u64 t1, t2, t3; 85 unsigned long long rv; 86 u64 mult = clocksource_mips.mult; 87 u64 shift = clocksource_mips.shift; 88 u64 cnt = read_c0_cvmcount(); 89 90 asm ( 91 "dmultu\t%[cnt],%[mult]\n\t" 92 "nor\t%[t1],$0,%[shift]\n\t" 93 "mfhi\t%[t2]\n\t" 94 "mflo\t%[t3]\n\t" 95 "dsll\t%[t2],%[t2],1\n\t" 96 "dsrlv\t%[rv],%[t3],%[shift]\n\t" 97 "dsllv\t%[t1],%[t2],%[t1]\n\t" 98 "or\t%[rv],%[t1],%[rv]\n\t" 99 : [rv] "=&r" (rv), [t1] "=&r" (t1), [t2] "=&r" (t2), [t3] "=&r" (t3) 100 : [cnt] "r" (cnt), [mult] "r" (mult), [shift] "r" (shift) 101 : "hi", "lo"); 102 return rv; 103 } 104 105 void __init plat_time_init(void) 106 { 107 clocksource_mips.rating = 300; 108 clocksource_set_clock(&clocksource_mips, octeon_get_clock_rate()); 109 clocksource_register(&clocksource_mips); 110 } 111 112 static u64 octeon_udelay_factor; 113 static u64 octeon_ndelay_factor; 114 115 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 } 126 127 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); 140 141 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); 154 155 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