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fbd8ae10 DS |
1 | /* |
2 | * Timer device implementation for SGI UV platform. | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * Copyright (c) 2009 Silicon Graphics, Inc. All rights reserved. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/ioctl.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/fs.h> | |
20 | #include <linux/mmtimer.h> | |
21 | #include <linux/miscdevice.h> | |
22 | #include <linux/posix-timers.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/time.h> | |
25 | #include <linux/math64.h> | |
26 | #include <linux/smp_lock.h> | |
27 | ||
28 | #include <asm/genapic.h> | |
29 | #include <asm/uv/uv_hub.h> | |
30 | #include <asm/uv/bios.h> | |
31 | #include <asm/uv/uv.h> | |
32 | ||
33 | MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>"); | |
34 | MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer"); | |
35 | MODULE_LICENSE("GPL"); | |
36 | ||
37 | /* name of the device, usually in /dev */ | |
38 | #define UV_MMTIMER_NAME "mmtimer" | |
39 | #define UV_MMTIMER_DESC "SGI UV Memory Mapped RTC Timer" | |
40 | #define UV_MMTIMER_VERSION "1.0" | |
41 | ||
42 | static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd, | |
43 | unsigned long arg); | |
44 | static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma); | |
45 | ||
46 | /* | |
47 | * Period in femtoseconds (10^-15 s) | |
48 | */ | |
49 | static unsigned long uv_mmtimer_femtoperiod; | |
50 | ||
51 | static const struct file_operations uv_mmtimer_fops = { | |
52 | .owner = THIS_MODULE, | |
53 | .mmap = uv_mmtimer_mmap, | |
54 | .unlocked_ioctl = uv_mmtimer_ioctl, | |
55 | }; | |
56 | ||
57 | /** | |
58 | * uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer | |
59 | * @file: file structure for the device | |
60 | * @cmd: command to execute | |
61 | * @arg: optional argument to command | |
62 | * | |
63 | * Executes the command specified by @cmd. Returns 0 for success, < 0 for | |
64 | * failure. | |
65 | * | |
66 | * Valid commands: | |
67 | * | |
68 | * %MMTIMER_GETOFFSET - Should return the offset (relative to the start | |
69 | * of the page where the registers are mapped) for the counter in question. | |
70 | * | |
71 | * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15) | |
72 | * seconds | |
73 | * | |
74 | * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address | |
75 | * specified by @arg | |
76 | * | |
77 | * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter | |
78 | * | |
79 | * %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace | |
80 | * | |
81 | * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it | |
82 | * in the address specified by @arg. | |
83 | */ | |
84 | static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd, | |
85 | unsigned long arg) | |
86 | { | |
87 | int ret = 0; | |
88 | ||
89 | switch (cmd) { | |
90 | case MMTIMER_GETOFFSET: /* offset of the counter */ | |
91 | /* | |
92 | * UV RTC register is on its own page | |
93 | */ | |
94 | if (PAGE_SIZE <= (1 << 16)) | |
95 | ret = ((UV_LOCAL_MMR_BASE | UVH_RTC) & (PAGE_SIZE-1)) | |
96 | / 8; | |
97 | else | |
98 | ret = -ENOSYS; | |
99 | break; | |
100 | ||
101 | case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */ | |
102 | if (copy_to_user((unsigned long __user *)arg, | |
103 | &uv_mmtimer_femtoperiod, sizeof(unsigned long))) | |
104 | ret = -EFAULT; | |
105 | break; | |
106 | ||
107 | case MMTIMER_GETFREQ: /* frequency in Hz */ | |
108 | if (copy_to_user((unsigned long __user *)arg, | |
109 | &sn_rtc_cycles_per_second, | |
110 | sizeof(unsigned long))) | |
111 | ret = -EFAULT; | |
112 | break; | |
113 | ||
114 | case MMTIMER_GETBITS: /* number of bits in the clock */ | |
115 | ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK); | |
116 | break; | |
117 | ||
118 | case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */ | |
119 | ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0; | |
120 | break; | |
121 | ||
122 | case MMTIMER_GETCOUNTER: | |
123 | if (copy_to_user((unsigned long __user *)arg, | |
124 | (unsigned long *)uv_local_mmr_address(UVH_RTC), | |
125 | sizeof(unsigned long))) | |
126 | ret = -EFAULT; | |
127 | break; | |
128 | default: | |
129 | ret = -ENOTTY; | |
130 | break; | |
131 | } | |
132 | return ret; | |
133 | } | |
134 | ||
135 | /** | |
136 | * uv_mmtimer_mmap - maps the clock's registers into userspace | |
137 | * @file: file structure for the device | |
138 | * @vma: VMA to map the registers into | |
139 | * | |
140 | * Calls remap_pfn_range() to map the clock's registers into | |
141 | * the calling process' address space. | |
142 | */ | |
143 | static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma) | |
144 | { | |
145 | unsigned long uv_mmtimer_addr; | |
146 | ||
147 | if (vma->vm_end - vma->vm_start != PAGE_SIZE) | |
148 | return -EINVAL; | |
149 | ||
150 | if (vma->vm_flags & VM_WRITE) | |
151 | return -EPERM; | |
152 | ||
153 | if (PAGE_SIZE > (1 << 16)) | |
154 | return -ENOSYS; | |
155 | ||
156 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
157 | ||
158 | uv_mmtimer_addr = UV_LOCAL_MMR_BASE | UVH_RTC; | |
159 | uv_mmtimer_addr &= ~(PAGE_SIZE - 1); | |
160 | uv_mmtimer_addr &= 0xfffffffffffffffUL; | |
161 | ||
162 | if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT, | |
163 | PAGE_SIZE, vma->vm_page_prot)) { | |
164 | printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n"); | |
165 | return -EAGAIN; | |
166 | } | |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
171 | static struct miscdevice uv_mmtimer_miscdev = { | |
172 | MISC_DYNAMIC_MINOR, | |
173 | UV_MMTIMER_NAME, | |
174 | &uv_mmtimer_fops | |
175 | }; | |
176 | ||
177 | ||
178 | /** | |
179 | * uv_mmtimer_init - device initialization routine | |
180 | * | |
181 | * Does initial setup for the uv_mmtimer device. | |
182 | */ | |
183 | static int __init uv_mmtimer_init(void) | |
184 | { | |
185 | if (!is_uv_system()) { | |
186 | printk(KERN_ERR "%s: Hardware unsupported\n", UV_MMTIMER_NAME); | |
187 | return -1; | |
188 | } | |
189 | ||
190 | /* | |
191 | * Sanity check the cycles/sec variable | |
192 | */ | |
193 | if (sn_rtc_cycles_per_second < 100000) { | |
194 | printk(KERN_ERR "%s: unable to determine clock frequency\n", | |
195 | UV_MMTIMER_NAME); | |
196 | return -1; | |
197 | } | |
198 | ||
199 | uv_mmtimer_femtoperiod = ((unsigned long)1E15 + | |
200 | sn_rtc_cycles_per_second / 2) / | |
201 | sn_rtc_cycles_per_second; | |
202 | ||
203 | if (misc_register(&uv_mmtimer_miscdev)) { | |
204 | printk(KERN_ERR "%s: failed to register device\n", | |
205 | UV_MMTIMER_NAME); | |
206 | return -1; | |
207 | } | |
208 | ||
209 | printk(KERN_INFO "%s: v%s, %ld MHz\n", UV_MMTIMER_DESC, | |
210 | UV_MMTIMER_VERSION, | |
211 | sn_rtc_cycles_per_second/(unsigned long)1E6); | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | module_init(uv_mmtimer_init); |