blob: 8110460558ff96c4e698f04666a96a84d8356f34 [file] [log] [blame]
Andres Salomon82dca612009-12-14 18:00:37 -08001/*
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>
21
22#define DRV_NAME "cs5535-mfgpt"
23#define MFGPT_BAR 2
24
25static int mfgpt_reset_timers;
26module_param_named(mfgptfix, mfgpt_reset_timers, int, 0644);
27MODULE_PARM_DESC(mfgptfix, "Reset the MFGPT timers during init; "
28 "required by some broken BIOSes (ie, TinyBIOS < 0.99).");
29
30struct cs5535_mfgpt_timer {
31 struct cs5535_mfgpt_chip *chip;
32 int nr;
33};
34
35static struct cs5535_mfgpt_chip {
36 DECLARE_BITMAP(avail, MFGPT_MAX_TIMERS);
37 resource_size_t base;
38
39 struct pci_dev *pdev;
40 spinlock_t lock;
41 int initialized;
42} cs5535_mfgpt_chip;
43
44int cs5535_mfgpt_toggle_event(struct cs5535_mfgpt_timer *timer, int cmp,
45 int event, int enable)
46{
47 uint32_t msr, mask, value, dummy;
48 int shift = (cmp == MFGPT_CMP1) ? 0 : 8;
49
50 if (!timer) {
51 WARN_ON(1);
52 return -EIO;
53 }
54
55 /*
56 * The register maps for these are described in sections 6.17.1.x of
57 * the AMD Geode CS5536 Companion Device Data Book.
58 */
59 switch (event) {
60 case MFGPT_EVENT_RESET:
61 /*
62 * XXX: According to the docs, we cannot reset timers above
63 * 6; that is, resets for 7 and 8 will be ignored. Is this
64 * a problem? -dilinger
65 */
66 msr = MSR_MFGPT_NR;
67 mask = 1 << (timer->nr + 24);
68 break;
69
70 case MFGPT_EVENT_NMI:
71 msr = MSR_MFGPT_NR;
72 mask = 1 << (timer->nr + shift);
73 break;
74
75 case MFGPT_EVENT_IRQ:
76 msr = MSR_MFGPT_IRQ;
77 mask = 1 << (timer->nr + shift);
78 break;
79
80 default:
81 return -EIO;
82 }
83
84 rdmsr(msr, value, dummy);
85
86 if (enable)
87 value |= mask;
88 else
89 value &= ~mask;
90
91 wrmsr(msr, value, dummy);
92 return 0;
93}
94EXPORT_SYMBOL_GPL(cs5535_mfgpt_toggle_event);
95
96int cs5535_mfgpt_set_irq(struct cs5535_mfgpt_timer *timer, int cmp, int *irq,
97 int enable)
98{
99 uint32_t zsel, lpc, dummy;
100 int shift;
101
102 if (!timer) {
103 WARN_ON(1);
104 return -EIO;
105 }
106
107 /*
108 * Unfortunately, MFGPTs come in pairs sharing their IRQ lines. If VSA
109 * is using the same CMP of the timer's Siamese twin, the IRQ is set to
110 * 2, and we mustn't use nor change it.
111 * XXX: Likewise, 2 Linux drivers might clash if the 2nd overwrites the
112 * IRQ of the 1st. This can only happen if forcing an IRQ, calling this
113 * with *irq==0 is safe. Currently there _are_ no 2 drivers.
114 */
115 rdmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
116 shift = ((cmp == MFGPT_CMP1 ? 0 : 4) + timer->nr % 4) * 4;
117 if (((zsel >> shift) & 0xF) == 2)
118 return -EIO;
119
120 /* Choose IRQ: if none supplied, keep IRQ already set or use default */
121 if (!*irq)
122 *irq = (zsel >> shift) & 0xF;
123 if (!*irq)
124 *irq = CONFIG_CS5535_MFGPT_DEFAULT_IRQ;
125
126 /* Can't use IRQ if it's 0 (=disabled), 2, or routed to LPC */
127 if (*irq < 1 || *irq == 2 || *irq > 15)
128 return -EIO;
129 rdmsr(MSR_PIC_IRQM_LPC, lpc, dummy);
130 if (lpc & (1 << *irq))
131 return -EIO;
132
133 /* All chosen and checked - go for it */
134 if (cs5535_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable))
135 return -EIO;
136 if (enable) {
137 zsel = (zsel & ~(0xF << shift)) | (*irq << shift);
138 wrmsr(MSR_PIC_ZSEL_LOW, zsel, dummy);
139 }
140
141 return 0;
142}
143EXPORT_SYMBOL_GPL(cs5535_mfgpt_set_irq);
144
145struct cs5535_mfgpt_timer *cs5535_mfgpt_alloc_timer(int timer_nr, int domain)
146{
147 struct cs5535_mfgpt_chip *mfgpt = &cs5535_mfgpt_chip;
148 struct cs5535_mfgpt_timer *timer = NULL;
149 unsigned long flags;
150 int max;
151
152 if (!mfgpt->initialized)
153 goto done;
154
155 /* only allocate timers from the working domain if requested */
156 if (domain == MFGPT_DOMAIN_WORKING)
157 max = 6;
158 else
159 max = MFGPT_MAX_TIMERS;
160
161 if (timer_nr >= max) {
162 /* programmer error. silly programmers! */
163 WARN_ON(1);
164 goto done;
165 }
166
167 spin_lock_irqsave(&mfgpt->lock, flags);
168 if (timer_nr < 0) {
169 unsigned long t;
170
171 /* try to find any available timer */
172 t = find_first_bit(mfgpt->avail, max);
173 /* set timer_nr to -1 if no timers available */
174 timer_nr = t < max ? (int) t : -1;
175 } else {
176 /* check if the requested timer's available */
177 if (test_bit(timer_nr, mfgpt->avail))
178 timer_nr = -1;
179 }
180
181 if (timer_nr >= 0)
182 /* if timer_nr is not -1, it's an available timer */
183 __clear_bit(timer_nr, mfgpt->avail);
184 spin_unlock_irqrestore(&mfgpt->lock, flags);
185
186 if (timer_nr < 0)
187 goto done;
188
189 timer = kmalloc(sizeof(*timer), GFP_KERNEL);
190 if (!timer) {
191 /* aw hell */
192 spin_lock_irqsave(&mfgpt->lock, flags);
193 __set_bit(timer_nr, mfgpt->avail);
194 spin_unlock_irqrestore(&mfgpt->lock, flags);
195 goto done;
196 }
197 timer->chip = mfgpt;
198 timer->nr = timer_nr;
199 dev_info(&mfgpt->pdev->dev, "registered timer %d\n", timer_nr);
200
201done:
202 return timer;
203}
204EXPORT_SYMBOL_GPL(cs5535_mfgpt_alloc_timer);
205
206/*
207 * XXX: This frees the timer memory, but never resets the actual hardware
208 * timer. The old geode_mfgpt code did this; it would be good to figure
209 * out a way to actually release the hardware timer. See comments below.
210 */
211void cs5535_mfgpt_free_timer(struct cs5535_mfgpt_timer *timer)
212{
213 kfree(timer);
214}
215EXPORT_SYMBOL_GPL(cs5535_mfgpt_free_timer);
216
217uint16_t cs5535_mfgpt_read(struct cs5535_mfgpt_timer *timer, uint16_t reg)
218{
219 return inw(timer->chip->base + reg + (timer->nr * 8));
220}
221EXPORT_SYMBOL_GPL(cs5535_mfgpt_read);
222
223void cs5535_mfgpt_write(struct cs5535_mfgpt_timer *timer, uint16_t reg,
224 uint16_t value)
225{
226 outw(value, timer->chip->base + reg + (timer->nr * 8));
227}
228EXPORT_SYMBOL_GPL(cs5535_mfgpt_write);
229
230/*
231 * This is a sledgehammer that resets all MFGPT timers. This is required by
232 * some broken BIOSes which leave the system in an unstable state
233 * (TinyBIOS 0.98, for example; fixed in 0.99). It's uncertain as to
234 * whether or not this secret MSR can be used to release individual timers.
235 * Jordan tells me that he and Mitch once played w/ it, but it's unclear
236 * what the results of that were (and they experienced some instability).
237 */
238static void __init reset_all_timers(void)
239{
240 uint32_t val, dummy;
241
242 /* The following undocumented bit resets the MFGPT timers */
243 val = 0xFF; dummy = 0;
244 wrmsr(MSR_MFGPT_SETUP, val, dummy);
245}
246
247/*
248 * Check whether any MFGPTs are available for the kernel to use. In most
249 * cases, firmware that uses AMD's VSA code will claim all timers during
250 * bootup; we certainly don't want to take them if they're already in use.
251 * In other cases (such as with VSAless OpenFirmware), the system firmware
252 * leaves timers available for us to use.
253 */
254static int __init scan_timers(struct cs5535_mfgpt_chip *mfgpt)
255{
256 struct cs5535_mfgpt_timer timer = { .chip = mfgpt };
257 unsigned long flags;
258 int timers = 0;
259 uint16_t val;
260 int i;
261
262 /* bios workaround */
263 if (mfgpt_reset_timers)
264 reset_all_timers();
265
266 /* just to be safe, protect this section w/ lock */
267 spin_lock_irqsave(&mfgpt->lock, flags);
268 for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
269 timer.nr = i;
270 val = cs5535_mfgpt_read(&timer, MFGPT_REG_SETUP);
271 if (!(val & MFGPT_SETUP_SETUP)) {
272 __set_bit(i, mfgpt->avail);
273 timers++;
274 }
275 }
276 spin_unlock_irqrestore(&mfgpt->lock, flags);
277
278 return timers;
279}
280
281static int __init cs5535_mfgpt_probe(struct pci_dev *pdev,
282 const struct pci_device_id *pci_id)
283{
284 int err, t;
285
286 /* There are two ways to get the MFGPT base address; one is by
287 * fetching it from MSR_LBAR_MFGPT, the other is by reading the
288 * PCI BAR info. The latter method is easier (especially across
289 * different architectures), so we'll stick with that for now. If
290 * it turns out to be unreliable in the face of crappy BIOSes, we
291 * can always go back to using MSRs.. */
292
293 err = pci_enable_device_io(pdev);
294 if (err) {
295 dev_err(&pdev->dev, "can't enable device IO\n");
296 goto done;
297 }
298
299 err = pci_request_region(pdev, MFGPT_BAR, DRV_NAME);
300 if (err) {
301 dev_err(&pdev->dev, "can't alloc PCI BAR #%d\n", MFGPT_BAR);
302 goto done;
303 }
304
305 /* set up the driver-specific struct */
306 cs5535_mfgpt_chip.base = pci_resource_start(pdev, MFGPT_BAR);
307 cs5535_mfgpt_chip.pdev = pdev;
308 spin_lock_init(&cs5535_mfgpt_chip.lock);
309
310 dev_info(&pdev->dev, "allocated PCI BAR #%d: base 0x%llx\n", MFGPT_BAR,
311 (unsigned long long) cs5535_mfgpt_chip.base);
312
313 /* detect the available timers */
314 t = scan_timers(&cs5535_mfgpt_chip);
315 dev_info(&pdev->dev, DRV_NAME ": %d MFGPT timers available\n", t);
316 cs5535_mfgpt_chip.initialized = 1;
317 return 0;
318
319done:
320 return err;
321}
322
323static struct pci_device_id cs5535_mfgpt_pci_tbl[] = {
324 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) },
325 { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
326 { 0, },
327};
328MODULE_DEVICE_TABLE(pci, cs5535_mfgpt_pci_tbl);
329
330/*
331 * Just like with the cs5535-gpio driver, we can't use the standard PCI driver
332 * registration stuff. It only allows only one driver to bind to each PCI
333 * device, and we want the GPIO and MFGPT drivers to be able to share a PCI
334 * device. Instead, we manually scan for the PCI device, request a single
335 * region, and keep track of the devices that we're using.
336 */
337
338static int __init cs5535_mfgpt_scan_pci(void)
339{
340 struct pci_dev *pdev;
341 int err = -ENODEV;
342 int i;
343
344 for (i = 0; i < ARRAY_SIZE(cs5535_mfgpt_pci_tbl); i++) {
345 pdev = pci_get_device(cs5535_mfgpt_pci_tbl[i].vendor,
346 cs5535_mfgpt_pci_tbl[i].device, NULL);
347 if (pdev) {
348 err = cs5535_mfgpt_probe(pdev,
349 &cs5535_mfgpt_pci_tbl[i]);
350 if (err)
351 pci_dev_put(pdev);
352
353 /* we only support a single CS5535/6 southbridge */
354 break;
355 }
356 }
357
358 return err;
359}
360
361static int __init cs5535_mfgpt_init(void)
362{
363 return cs5535_mfgpt_scan_pci();
364}
365
366module_init(cs5535_mfgpt_init);
367
368MODULE_AUTHOR("Andres Salomon <dilinger@collabora.co.uk>");
369MODULE_DESCRIPTION("CS5535/CS5536 MFGPT timer driver");
370MODULE_LICENSE("GPL");