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authorDimitri Sivanich <sivanich@sgi.com>2009-09-23 18:57:15 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 10:21:03 -0400
commitfbd8ae106850b6a0215c2776e70a75a1b93cafc2 (patch)
tree88c63571c3daf7da4ce5779db4b12e99c9d90dff /drivers/char
parent459ca8b4ed1889b0a69bbe21888e6af136d495f3 (diff)
drivers/char/uv_mmtimer.c: add memory mapped RTC driver for UV
This driver memory maps the UV Hub RTC. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/Kconfig8
-rw-r--r--drivers/char/Makefile1
-rw-r--r--drivers/char/uv_mmtimer.c216
3 files changed, 225 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 6a06913b01d3..08a6f50ae791 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -1087,6 +1087,14 @@ config MMTIMER
1087 The mmtimer device allows direct userspace access to the 1087 The mmtimer device allows direct userspace access to the
1088 Altix system timer. 1088 Altix system timer.
1089 1089
1090config UV_MMTIMER
1091 tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
1092 depends on X86_UV
1093 default m
1094 help
1095 The uv_mmtimer device allows direct userspace access to the
1096 UV system timer.
1097
1090source "drivers/char/tpm/Kconfig" 1098source "drivers/char/tpm/Kconfig"
1091 1099
1092config TELCLOCK 1100config TELCLOCK
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 66f779ad4f4c..19a79dd79eee 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_RAW_DRIVER) += raw.o
58obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o 58obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
59obj-$(CONFIG_MSPEC) += mspec.o 59obj-$(CONFIG_MSPEC) += mspec.o
60obj-$(CONFIG_MMTIMER) += mmtimer.o 60obj-$(CONFIG_MMTIMER) += mmtimer.o
61obj-$(CONFIG_UV_MMTIMER) += uv_mmtimer.o
61obj-$(CONFIG_VIOTAPE) += viotape.o 62obj-$(CONFIG_VIOTAPE) += viotape.o
62obj-$(CONFIG_HVCS) += hvcs.o 63obj-$(CONFIG_HVCS) += hvcs.o
63obj-$(CONFIG_IBM_BSR) += bsr.o 64obj-$(CONFIG_IBM_BSR) += bsr.o
diff --git a/drivers/char/uv_mmtimer.c b/drivers/char/uv_mmtimer.c
new file mode 100644
index 000000000000..867b67be9f0a
--- /dev/null
+++ b/drivers/char/uv_mmtimer.c
@@ -0,0 +1,216 @@
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
33MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>");
34MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer");
35MODULE_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
42static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
43 unsigned long arg);
44static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
45
46/*
47 * Period in femtoseconds (10^-15 s)
48 */
49static unsigned long uv_mmtimer_femtoperiod;
50
51static 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 */
84static 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 */
143static 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
171static 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 */
183static 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
216module_init(uv_mmtimer_init);