1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/module.h> 3 #include <linux/smp.h> 4 #include <linux/time.h> 5 #include <linux/errno.h> 6 #include <linux/timex.h> 7 #include <linux/clocksource.h> 8 #include <linux/io.h> 9 10 /* IBM Summit (EXA) Cyclone counter code*/ 11 #define CYCLONE_CBAR_ADDR 0xFEB00CD0 12 #define CYCLONE_PMCC_OFFSET 0x51A0 13 #define CYCLONE_MPMC_OFFSET 0x51D0 14 #define CYCLONE_MPCS_OFFSET 0x51A8 15 #define CYCLONE_TIMER_FREQ 100000000 16 17 int use_cyclone; 18 void __init cyclone_setup(void) 19 { 20 use_cyclone = 1; 21 } 22 23 static void __iomem *cyclone_mc; 24 25 static u64 read_cyclone(struct clocksource *cs) 26 { 27 return (u64)readq((void __iomem *)cyclone_mc); 28 } 29 30 static struct clocksource clocksource_cyclone = { 31 .name = "cyclone", 32 .rating = 300, 33 .read = read_cyclone, 34 .mask = (1LL << 40) - 1, 35 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 36 }; 37 38 int __init init_cyclone_clock(void) 39 { 40 u64 __iomem *reg; 41 u64 base; /* saved cyclone base address */ 42 u64 offset; /* offset from pageaddr to cyclone_timer register */ 43 int i; 44 u32 __iomem *cyclone_timer; /* Cyclone MPMC0 register */ 45 46 if (!use_cyclone) 47 return 0; 48 49 printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n"); 50 51 /* find base address */ 52 offset = (CYCLONE_CBAR_ADDR); 53 reg = ioremap(offset, sizeof(u64)); 54 if(!reg){ 55 printk(KERN_ERR "Summit chipset: Could not find valid CBAR" 56 " register.\n"); 57 use_cyclone = 0; 58 return -ENODEV; 59 } 60 base = readq(reg); 61 iounmap(reg); 62 if(!base){ 63 printk(KERN_ERR "Summit chipset: Could not find valid CBAR" 64 " value.\n"); 65 use_cyclone = 0; 66 return -ENODEV; 67 } 68 69 /* setup PMCC */ 70 offset = (base + CYCLONE_PMCC_OFFSET); 71 reg = ioremap(offset, sizeof(u64)); 72 if(!reg){ 73 printk(KERN_ERR "Summit chipset: Could not find valid PMCC" 74 " register.\n"); 75 use_cyclone = 0; 76 return -ENODEV; 77 } 78 writel(0x00000001,reg); 79 iounmap(reg); 80 81 /* setup MPCS */ 82 offset = (base + CYCLONE_MPCS_OFFSET); 83 reg = ioremap(offset, sizeof(u64)); 84 if(!reg){ 85 printk(KERN_ERR "Summit chipset: Could not find valid MPCS" 86 " register.\n"); 87 use_cyclone = 0; 88 return -ENODEV; 89 } 90 writel(0x00000001,reg); 91 iounmap(reg); 92 93 /* map in cyclone_timer */ 94 offset = (base + CYCLONE_MPMC_OFFSET); 95 cyclone_timer = ioremap(offset, sizeof(u32)); 96 if(!cyclone_timer){ 97 printk(KERN_ERR "Summit chipset: Could not find valid MPMC" 98 " register.\n"); 99 use_cyclone = 0; 100 return -ENODEV; 101 } 102 103 /*quick test to make sure its ticking*/ 104 for(i=0; i<3; i++){ 105 u32 old = readl(cyclone_timer); 106 int stall = 100; 107 while(stall--) barrier(); 108 if(readl(cyclone_timer) == old){ 109 printk(KERN_ERR "Summit chipset: Counter not counting!" 110 " DISABLED\n"); 111 iounmap(cyclone_timer); 112 cyclone_timer = NULL; 113 use_cyclone = 0; 114 return -ENODEV; 115 } 116 } 117 /* initialize last tick */ 118 cyclone_mc = cyclone_timer; 119 clocksource_cyclone.archdata.fsys_mmio = cyclone_timer; 120 clocksource_register_hz(&clocksource_cyclone, CYCLONE_TIMER_FREQ); 121 122 return 0; 123 } 124 125 __initcall(init_cyclone_clock); 126