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1/*
2 * Driver for the CS5535/CS5536 Multi-Function General Purpose Timers (MFGPT)
3 *
4 * Copyright (C) 2006, Advanced Micro Devices, Inc.
5 * Copyright (C) 2007 Andres Salomon <dilinger@debian.org>
6 * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of version 2 of the GNU General Public License
10 * as published by the Free Software Foundation.
11 *
12 * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book.
13 */
14
15#include <linux/kernel.h>
16#include <linux/spinlock.h>
17#include <linux/interrupt.h>
18#include <linux/module.h>
19#include <linux/pci.h>
20#include <linux/cs5535.h>
5a0e3ad6 21#include <linux/slab.h>
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22
23#define DRV_NAME "cs5535-mfgpt"
24#define MFGPT_BAR 2
25
26static int mfgpt_reset_timers;
27module_param_named(mfgptfix, mfgpt_reset_timers, int, 0644);
28MODULE_PARM_DESC(mfgptfix, "Reset the MFGPT timers during init; "
29 "required by some broken BIOSes (ie, TinyBIOS < 0.99).");
30
31struct cs5535_mfgpt_timer {
32 struct cs5535_mfgpt_chip *chip;
33 int nr;
34};
35
36static struct cs5535_mfgpt_chip {
37 DECLARE_BITMAP(avail, MFGPT_MAX_TIMERS);
38 resource_size_t base;
39
40 struct pci_dev *pdev;
41 spinlock_t lock;
42 int initialized;
43} cs5535_mfgpt_chip;
44
45int cs5535_mfgpt_toggle_event(struct cs5535_mfgpt_timer *timer, int cmp,
46 int event, int enable)
47{
48 uint32_t msr, mask, value, dummy;
49 int shift = (cmp == MFGPT_CMP1) ? 0 : 8;
50
51 if (!timer) {
52 WARN_ON(1);
53 return -EIO;
54 }
55
56 /*
57 * The register maps for these are described in sections 6.17.1.x of
58 * the AMD Geode CS5536 Companion Device Data Book.
59 */
60 switch (event) {
61 case MFGPT_EVENT_RESET:
62 /*
63 * XXX: According to the docs, we cannot reset timers above
64 * 6; that is, resets for 7 and 8 will be ignored. Is this
65 * a problem? -dilinger
66 */
67 msr = MSR_MFGPT_NR;
68 mask = 1 << (timer->nr + 24);
69 break;
70
71 case MFGPT_EVENT_NMI:
72 msr = MSR_MFGPT_NR;
73 mask = 1 << (timer->nr + shift);
74 break;
75
76 case MFGPT_EVENT_IRQ:
77 msr = MSR_MFGPT_IRQ;
78 mask = 1 << (timer->nr + shift);
79 break;
80
81 default:
82 return -EIO;
83 }
84
85 rdmsr(msr, value, dummy);
86
87 if (enable)
88 value |= mask;
89 else
90 value &= ~mask;
91
92 wrmsr(msr, value, dummy);
93 return 0;
94}
95EXPORT_SYMBOL_GPL(cs5535_mfgpt_toggle_event);
96
97int cs5535_mfgpt_set_irq(struct cs5535_mfgpt_timer *timer, int cmp, int *irq,
98 int enable)
99{
100 uint32_t zsel, lpc, dummy;
101 int shift;
102
103 if (!timer) {
104 WARN_ON(1);
105 return -EIO;
106 }
107
108 /*
109 * Unfortunately, MFGPTs come in pairs sharing their IRQ lines. If VSA
110 * is using the same CMP of the timer's Siamese twin, the IRQ is set to
111 * 2, and we mustn't use nor change it.
112 * XXX: Likewise, 2 Linux drivers might clash if the 2nd overwrites the
113 * IRQ of the 1st. This can only happen if forcing an IRQ, calling this
114 * with *irq==0 is safe. Currently there _are_ no 2 drivers.
115 */
116 rdmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
117 shift = ((cmp == MFGPT_CMP1 ? 0 : 4) + timer->nr % 4) * 4;
118 if (((zsel >> shift) & 0xF) == 2)
119 return -EIO;
120
121 /* Choose IRQ: if none supplied, keep IRQ already set or use default */
122 if (!*irq)
123 *irq = (zsel >> shift) & 0xF;
124 if (!*irq)
125 *irq = CONFIG_CS5535_MFGPT_DEFAULT_IRQ;
126
127 /* Can't use IRQ if it's 0 (=disabled), 2, or routed to LPC */
128 if (*irq < 1 || *irq == 2 || *irq > 15)
129 return -EIO;
130 rdmsr(MSR_PIC_IRQM_LPC, lpc, dummy);
131 if (lpc & (1 << *irq))
132 return -EIO;
133
134 /* All chosen and checked - go for it */
135 if (cs5535_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable))
136 return -EIO;
137 if (enable) {
138 zsel = (zsel & ~(0xF << shift)) | (*irq << shift);
139 wrmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
140 }
141
142 return 0;
143}
144EXPORT_SYMBOL_GPL(cs5535_mfgpt_set_irq);
145
146struct cs5535_mfgpt_timer *cs5535_mfgpt_alloc_timer(int timer_nr, int domain)
147{
148 struct cs5535_mfgpt_chip *mfgpt = &cs5535_mfgpt_chip;
149 struct cs5535_mfgpt_timer *timer = NULL;
150 unsigned long flags;
151 int max;
152
153 if (!mfgpt->initialized)
154 goto done;
155
156 /* only allocate timers from the working domain if requested */
157 if (domain == MFGPT_DOMAIN_WORKING)
158 max = 6;
159 else
160 max = MFGPT_MAX_TIMERS;
161
162 if (timer_nr >= max) {
163 /* programmer error. silly programmers! */
164 WARN_ON(1);
165 goto done;
166 }
167
168 spin_lock_irqsave(&mfgpt->lock, flags);
169 if (timer_nr < 0) {
170 unsigned long t;
171
172 /* try to find any available timer */
173 t = find_first_bit(mfgpt->avail, max);
174 /* set timer_nr to -1 if no timers available */
175 timer_nr = t < max ? (int) t : -1;
176 } else {
177 /* check if the requested timer's available */
178 if (test_bit(timer_nr, mfgpt->avail))
179 timer_nr = -1;
180 }
181
182 if (timer_nr >= 0)
183 /* if timer_nr is not -1, it's an available timer */
184 __clear_bit(timer_nr, mfgpt->avail);
185 spin_unlock_irqrestore(&mfgpt->lock, flags);
186
187 if (timer_nr < 0)
188 goto done;
189
190 timer = kmalloc(sizeof(*timer), GFP_KERNEL);
191 if (!timer) {
192 /* aw hell */
193 spin_lock_irqsave(&mfgpt->lock, flags);
194 __set_bit(timer_nr, mfgpt->avail);
195 spin_unlock_irqrestore(&mfgpt->lock, flags);
196 goto done;
197 }
198 timer->chip = mfgpt;
199 timer->nr = timer_nr;
200 dev_info(&mfgpt->pdev->dev, "registered timer %d\n", timer_nr);
201
202done:
203 return timer;
204}
205EXPORT_SYMBOL_GPL(cs5535_mfgpt_alloc_timer);
206
207/*
208 * XXX: This frees the timer memory, but never resets the actual hardware
209 * timer. The old geode_mfgpt code did this; it would be good to figure
210 * out a way to actually release the hardware timer. See comments below.
211 */
212void cs5535_mfgpt_free_timer(struct cs5535_mfgpt_timer *timer)
213{
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214 unsigned long flags;
215 uint16_t val;
216
217 /* timer can be made available again only if never set up */
218 val = cs5535_mfgpt_read(timer, MFGPT_REG_SETUP);
219 if (!(val & MFGPT_SETUP_SETUP)) {
220 spin_lock_irqsave(&timer->chip->lock, flags);
221 __set_bit(timer->nr, timer->chip->avail);
222 spin_unlock_irqrestore(&timer->chip->lock, flags);
223 }
224
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225 kfree(timer);
226}
227EXPORT_SYMBOL_GPL(cs5535_mfgpt_free_timer);
228
229uint16_t cs5535_mfgpt_read(struct cs5535_mfgpt_timer *timer, uint16_t reg)
230{
231 return inw(timer->chip->base + reg + (timer->nr * 8));
232}
233EXPORT_SYMBOL_GPL(cs5535_mfgpt_read);
234
235void cs5535_mfgpt_write(struct cs5535_mfgpt_timer *timer, uint16_t reg,
236 uint16_t value)
237{
238 outw(value, timer->chip->base + reg + (timer->nr * 8));
239}
240EXPORT_SYMBOL_GPL(cs5535_mfgpt_write);
241
242/*
243 * This is a sledgehammer that resets all MFGPT timers. This is required by
244 * some broken BIOSes which leave the system in an unstable state
245 * (TinyBIOS 0.98, for example; fixed in 0.99). It's uncertain as to
246 * whether or not this secret MSR can be used to release individual timers.
247 * Jordan tells me that he and Mitch once played w/ it, but it's unclear
248 * what the results of that were (and they experienced some instability).
249 */
250static void __init reset_all_timers(void)
251{
252 uint32_t val, dummy;
253
254 /* The following undocumented bit resets the MFGPT timers */
255 val = 0xFF; dummy = 0;
256 wrmsr(MSR_MFGPT_SETUP, val, dummy);
257}
258
259/*
260 * Check whether any MFGPTs are available for the kernel to use. In most
261 * cases, firmware that uses AMD's VSA code will claim all timers during
262 * bootup; we certainly don't want to take them if they're already in use.
263 * In other cases (such as with VSAless OpenFirmware), the system firmware
264 * leaves timers available for us to use.
265 */
266static int __init scan_timers(struct cs5535_mfgpt_chip *mfgpt)
267{
268 struct cs5535_mfgpt_timer timer = { .chip = mfgpt };
269 unsigned long flags;
270 int timers = 0;
271 uint16_t val;
272 int i;
273
274 /* bios workaround */
275 if (mfgpt_reset_timers)
276 reset_all_timers();
277
278 /* just to be safe, protect this section w/ lock */
279 spin_lock_irqsave(&mfgpt->lock, flags);
280 for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
281 timer.nr = i;
282 val = cs5535_mfgpt_read(&timer, MFGPT_REG_SETUP);
283 if (!(val & MFGPT_SETUP_SETUP)) {
284 __set_bit(i, mfgpt->avail);
285 timers++;
286 }
287 }
288 spin_unlock_irqrestore(&mfgpt->lock, flags);
289
290 return timers;
291}
292
293static int __init cs5535_mfgpt_probe(struct pci_dev *pdev,
294 const struct pci_device_id *pci_id)
295{
296 int err, t;
297
298 /* There are two ways to get the MFGPT base address; one is by
299 * fetching it from MSR_LBAR_MFGPT, the other is by reading the
300 * PCI BAR info. The latter method is easier (especially across
301 * different architectures), so we'll stick with that for now. If
302 * it turns out to be unreliable in the face of crappy BIOSes, we
303 * can always go back to using MSRs.. */
304
305 err = pci_enable_device_io(pdev);
306 if (err) {
307 dev_err(&pdev->dev, "can't enable device IO\n");
308 goto done;
309 }
310
311 err = pci_request_region(pdev, MFGPT_BAR, DRV_NAME);
312 if (err) {
313 dev_err(&pdev->dev, "can't alloc PCI BAR #%d\n", MFGPT_BAR);
314 goto done;
315 }
316
317 /* set up the driver-specific struct */
318 cs5535_mfgpt_chip.base = pci_resource_start(pdev, MFGPT_BAR);
319 cs5535_mfgpt_chip.pdev = pdev;
320 spin_lock_init(&cs5535_mfgpt_chip.lock);
321
322 dev_info(&pdev->dev, "allocated PCI BAR #%d: base 0x%llx\n", MFGPT_BAR,
323 (unsigned long long) cs5535_mfgpt_chip.base);
324
325 /* detect the available timers */
326 t = scan_timers(&cs5535_mfgpt_chip);
327 dev_info(&pdev->dev, DRV_NAME ": %d MFGPT timers available\n", t);
328 cs5535_mfgpt_chip.initialized = 1;
329 return 0;
330
331done:
332 return err;
333}
334
335static struct pci_device_id cs5535_mfgpt_pci_tbl[] = {
336 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) },
337 { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
338 { 0, },
339};
340MODULE_DEVICE_TABLE(pci, cs5535_mfgpt_pci_tbl);
341
342/*
343 * Just like with the cs5535-gpio driver, we can't use the standard PCI driver
344 * registration stuff. It only allows only one driver to bind to each PCI
345 * device, and we want the GPIO and MFGPT drivers to be able to share a PCI
346 * device. Instead, we manually scan for the PCI device, request a single
347 * region, and keep track of the devices that we're using.
348 */
349
350static int __init cs5535_mfgpt_scan_pci(void)
351{
352 struct pci_dev *pdev;
353 int err = -ENODEV;
354 int i;
355
356 for (i = 0; i < ARRAY_SIZE(cs5535_mfgpt_pci_tbl); i++) {
357 pdev = pci_get_device(cs5535_mfgpt_pci_tbl[i].vendor,
358 cs5535_mfgpt_pci_tbl[i].device, NULL);
359 if (pdev) {
360 err = cs5535_mfgpt_probe(pdev,
361 &cs5535_mfgpt_pci_tbl[i]);
362 if (err)
363 pci_dev_put(pdev);
364
365 /* we only support a single CS5535/6 southbridge */
366 break;
367 }
368 }
369
370 return err;
371}
372
373static int __init cs5535_mfgpt_init(void)
374{
375 return cs5535_mfgpt_scan_pci();
376}
377
378module_init(cs5535_mfgpt_init);
379
d45840d9 380MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
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381MODULE_DESCRIPTION("CS5535/CS5536 MFGPT timer driver");
382MODULE_LICENSE("GPL");