BKL: remove extraneous #include <smp_lock.h>
[linux-3.10.git] / drivers / char / uv_mmtimer.c
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
27 #include <asm/genapic.h>
28 #include <asm/uv/uv_hub.h>
29 #include <asm/uv/bios.h>
30 #include <asm/uv/uv.h>
31
32 MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>");
33 MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer");
34 MODULE_LICENSE("GPL");
35
36 /* name of the device, usually in /dev */
37 #define UV_MMTIMER_NAME "mmtimer"
38 #define UV_MMTIMER_DESC "SGI UV Memory Mapped RTC Timer"
39 #define UV_MMTIMER_VERSION "1.0"
40
41 static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
42                                                 unsigned long arg);
43 static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
44
45 /*
46  * Period in femtoseconds (10^-15 s)
47  */
48 static unsigned long uv_mmtimer_femtoperiod;
49
50 static const struct file_operations uv_mmtimer_fops = {
51         .owner = THIS_MODULE,
52         .mmap = uv_mmtimer_mmap,
53         .unlocked_ioctl = uv_mmtimer_ioctl,
54         .llseek = noop_llseek,
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                  * Starting with HUB rev 2.0, the UV RTC register is
93                  * replicated across all cachelines of it's own page.
94                  * This allows faster simultaneous reads from a given socket.
95                  *
96                  * The offset returned is in 64 bit units.
97                  */
98                 if (uv_get_min_hub_revision_id() == 1)
99                         ret = 0;
100                 else
101                         ret = ((uv_blade_processor_id() * L1_CACHE_BYTES) %
102                                         PAGE_SIZE) / 8;
103                 break;
104
105         case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
106                 if (copy_to_user((unsigned long __user *)arg,
107                                 &uv_mmtimer_femtoperiod, sizeof(unsigned long)))
108                         ret = -EFAULT;
109                 break;
110
111         case MMTIMER_GETFREQ: /* frequency in Hz */
112                 if (copy_to_user((unsigned long __user *)arg,
113                                 &sn_rtc_cycles_per_second,
114                                 sizeof(unsigned long)))
115                         ret = -EFAULT;
116                 break;
117
118         case MMTIMER_GETBITS: /* number of bits in the clock */
119                 ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK);
120                 break;
121
122         case MMTIMER_MMAPAVAIL:
123                 ret = 1;
124                 break;
125
126         case MMTIMER_GETCOUNTER:
127                 if (copy_to_user((unsigned long __user *)arg,
128                                 (unsigned long *)uv_local_mmr_address(UVH_RTC),
129                                 sizeof(unsigned long)))
130                         ret = -EFAULT;
131                 break;
132         default:
133                 ret = -ENOTTY;
134                 break;
135         }
136         return ret;
137 }
138
139 /**
140  * uv_mmtimer_mmap - maps the clock's registers into userspace
141  * @file: file structure for the device
142  * @vma: VMA to map the registers into
143  *
144  * Calls remap_pfn_range() to map the clock's registers into
145  * the calling process' address space.
146  */
147 static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
148 {
149         unsigned long uv_mmtimer_addr;
150
151         if (vma->vm_end - vma->vm_start != PAGE_SIZE)
152                 return -EINVAL;
153
154         if (vma->vm_flags & VM_WRITE)
155                 return -EPERM;
156
157         if (PAGE_SIZE > (1 << 16))
158                 return -ENOSYS;
159
160         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
161
162         uv_mmtimer_addr = UV_LOCAL_MMR_BASE | UVH_RTC;
163         uv_mmtimer_addr &= ~(PAGE_SIZE - 1);
164         uv_mmtimer_addr &= 0xfffffffffffffffUL;
165
166         if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT,
167                                         PAGE_SIZE, vma->vm_page_prot)) {
168                 printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n");
169                 return -EAGAIN;
170         }
171
172         return 0;
173 }
174
175 static struct miscdevice uv_mmtimer_miscdev = {
176         MISC_DYNAMIC_MINOR,
177         UV_MMTIMER_NAME,
178         &uv_mmtimer_fops
179 };
180
181
182 /**
183  * uv_mmtimer_init - device initialization routine
184  *
185  * Does initial setup for the uv_mmtimer device.
186  */
187 static int __init uv_mmtimer_init(void)
188 {
189         if (!is_uv_system()) {
190                 printk(KERN_ERR "%s: Hardware unsupported\n", UV_MMTIMER_NAME);
191                 return -1;
192         }
193
194         /*
195          * Sanity check the cycles/sec variable
196          */
197         if (sn_rtc_cycles_per_second < 100000) {
198                 printk(KERN_ERR "%s: unable to determine clock frequency\n",
199                        UV_MMTIMER_NAME);
200                 return -1;
201         }
202
203         uv_mmtimer_femtoperiod = ((unsigned long)1E15 +
204                                 sn_rtc_cycles_per_second / 2) /
205                                 sn_rtc_cycles_per_second;
206
207         if (misc_register(&uv_mmtimer_miscdev)) {
208                 printk(KERN_ERR "%s: failed to register device\n",
209                        UV_MMTIMER_NAME);
210                 return -1;
211         }
212
213         printk(KERN_INFO "%s: v%s, %ld MHz\n", UV_MMTIMER_DESC,
214                 UV_MMTIMER_VERSION,
215                 sn_rtc_cycles_per_second/(unsigned long)1E6);
216
217         return 0;
218 }
219
220 module_init(uv_mmtimer_init);