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25763b3c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
82dca611 AS |
2 | /* |
3 | * Driver for the CS5535/CS5536 Multi-Function General Purpose Timers (MFGPT) | |
4 | * | |
5 | * Copyright (C) 2006, Advanced Micro Devices, Inc. | |
6 | * Copyright (C) 2007 Andres Salomon <dilinger@debian.org> | |
7 | * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk> | |
8 | * | |
82dca611 AS |
9 | * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book. |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/spinlock.h> | |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/module.h> | |
69bc6def | 16 | #include <linux/platform_device.h> |
82dca611 | 17 | #include <linux/cs5535.h> |
5a0e3ad6 | 18 | #include <linux/slab.h> |
82dca611 AS |
19 | |
20 | #define DRV_NAME "cs5535-mfgpt" | |
82dca611 AS |
21 | |
22 | static int mfgpt_reset_timers; | |
23 | module_param_named(mfgptfix, mfgpt_reset_timers, int, 0644); | |
945480b1 RW |
24 | MODULE_PARM_DESC(mfgptfix, "Try to reset the MFGPT timers during init; " |
25 | "required by some broken BIOSes (ie, TinyBIOS < 0.99) or kexec " | |
26 | "(1 = reset the MFGPT using an undocumented bit, " | |
33facb4d RW |
27 | "2 = perform a soft reset by unconfiguring all timers); " |
28 | "use what works best for you."); | |
82dca611 AS |
29 | |
30 | struct cs5535_mfgpt_timer { | |
31 | struct cs5535_mfgpt_chip *chip; | |
32 | int nr; | |
33 | }; | |
34 | ||
35 | static struct cs5535_mfgpt_chip { | |
36 | DECLARE_BITMAP(avail, MFGPT_MAX_TIMERS); | |
37 | resource_size_t base; | |
38 | ||
69bc6def | 39 | struct platform_device *pdev; |
82dca611 AS |
40 | spinlock_t lock; |
41 | int initialized; | |
42 | } cs5535_mfgpt_chip; | |
43 | ||
44 | int 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 | } | |
94 | EXPORT_SYMBOL_GPL(cs5535_mfgpt_toggle_event); | |
95 | ||
96 | int 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 | } | |
143 | EXPORT_SYMBOL_GPL(cs5535_mfgpt_set_irq); | |
144 | ||
145 | struct 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 */ | |
4bbd61fb | 177 | if (!test_bit(timer_nr, mfgpt->avail)) |
82dca611 AS |
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 | ||
201 | done: | |
202 | return timer; | |
203 | } | |
204 | EXPORT_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 | */ | |
211 | void cs5535_mfgpt_free_timer(struct cs5535_mfgpt_timer *timer) | |
212 | { | |
ecd62691 JR |
213 | unsigned long flags; |
214 | uint16_t val; | |
215 | ||
216 | /* timer can be made available again only if never set up */ | |
217 | val = cs5535_mfgpt_read(timer, MFGPT_REG_SETUP); | |
218 | if (!(val & MFGPT_SETUP_SETUP)) { | |
219 | spin_lock_irqsave(&timer->chip->lock, flags); | |
220 | __set_bit(timer->nr, timer->chip->avail); | |
221 | spin_unlock_irqrestore(&timer->chip->lock, flags); | |
222 | } | |
223 | ||
82dca611 AS |
224 | kfree(timer); |
225 | } | |
226 | EXPORT_SYMBOL_GPL(cs5535_mfgpt_free_timer); | |
227 | ||
228 | uint16_t cs5535_mfgpt_read(struct cs5535_mfgpt_timer *timer, uint16_t reg) | |
229 | { | |
230 | return inw(timer->chip->base + reg + (timer->nr * 8)); | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(cs5535_mfgpt_read); | |
233 | ||
234 | void cs5535_mfgpt_write(struct cs5535_mfgpt_timer *timer, uint16_t reg, | |
235 | uint16_t value) | |
236 | { | |
237 | outw(value, timer->chip->base + reg + (timer->nr * 8)); | |
238 | } | |
239 | EXPORT_SYMBOL_GPL(cs5535_mfgpt_write); | |
240 | ||
241 | /* | |
242 | * This is a sledgehammer that resets all MFGPT timers. This is required by | |
243 | * some broken BIOSes which leave the system in an unstable state | |
244 | * (TinyBIOS 0.98, for example; fixed in 0.99). It's uncertain as to | |
245 | * whether or not this secret MSR can be used to release individual timers. | |
246 | * Jordan tells me that he and Mitch once played w/ it, but it's unclear | |
247 | * what the results of that were (and they experienced some instability). | |
248 | */ | |
80c8ae28 | 249 | static void reset_all_timers(void) |
82dca611 AS |
250 | { |
251 | uint32_t val, dummy; | |
252 | ||
253 | /* The following undocumented bit resets the MFGPT timers */ | |
254 | val = 0xFF; dummy = 0; | |
255 | wrmsr(MSR_MFGPT_SETUP, val, dummy); | |
256 | } | |
257 | ||
945480b1 RW |
258 | /* |
259 | * This is another sledgehammer to reset all MFGPT timers. | |
260 | * Instead of using the undocumented bit method it clears | |
261 | * IRQ, NMI and RESET settings. | |
262 | */ | |
263 | static void soft_reset(void) | |
264 | { | |
265 | int i; | |
266 | struct cs5535_mfgpt_timer t; | |
267 | ||
268 | for (i = 0; i < MFGPT_MAX_TIMERS; i++) { | |
269 | t.nr = i; | |
270 | ||
271 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP1, MFGPT_EVENT_RESET, 0); | |
272 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP2, MFGPT_EVENT_RESET, 0); | |
273 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP1, MFGPT_EVENT_NMI, 0); | |
274 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP2, MFGPT_EVENT_NMI, 0); | |
275 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP1, MFGPT_EVENT_IRQ, 0); | |
276 | cs5535_mfgpt_toggle_event(&t, MFGPT_CMP2, MFGPT_EVENT_IRQ, 0); | |
277 | } | |
278 | } | |
279 | ||
82dca611 AS |
280 | /* |
281 | * Check whether any MFGPTs are available for the kernel to use. In most | |
282 | * cases, firmware that uses AMD's VSA code will claim all timers during | |
283 | * bootup; we certainly don't want to take them if they're already in use. | |
284 | * In other cases (such as with VSAless OpenFirmware), the system firmware | |
285 | * leaves timers available for us to use. | |
286 | */ | |
80c8ae28 | 287 | static int scan_timers(struct cs5535_mfgpt_chip *mfgpt) |
82dca611 AS |
288 | { |
289 | struct cs5535_mfgpt_timer timer = { .chip = mfgpt }; | |
290 | unsigned long flags; | |
291 | int timers = 0; | |
292 | uint16_t val; | |
293 | int i; | |
294 | ||
295 | /* bios workaround */ | |
945480b1 | 296 | if (mfgpt_reset_timers == 1) |
82dca611 | 297 | reset_all_timers(); |
945480b1 RW |
298 | else if (mfgpt_reset_timers == 2) |
299 | soft_reset(); | |
82dca611 AS |
300 | |
301 | /* just to be safe, protect this section w/ lock */ | |
302 | spin_lock_irqsave(&mfgpt->lock, flags); | |
303 | for (i = 0; i < MFGPT_MAX_TIMERS; i++) { | |
304 | timer.nr = i; | |
305 | val = cs5535_mfgpt_read(&timer, MFGPT_REG_SETUP); | |
945480b1 | 306 | if (!(val & MFGPT_SETUP_SETUP) || mfgpt_reset_timers == 2) { |
82dca611 AS |
307 | __set_bit(i, mfgpt->avail); |
308 | timers++; | |
309 | } | |
310 | } | |
311 | spin_unlock_irqrestore(&mfgpt->lock, flags); | |
312 | ||
313 | return timers; | |
314 | } | |
315 | ||
80c8ae28 | 316 | static int cs5535_mfgpt_probe(struct platform_device *pdev) |
82dca611 | 317 | { |
69bc6def AS |
318 | struct resource *res; |
319 | int err = -EIO, t; | |
82dca611 | 320 | |
945480b1 RW |
321 | if (mfgpt_reset_timers < 0 || mfgpt_reset_timers > 2) { |
322 | dev_err(&pdev->dev, "Bad mfgpt_reset_timers value: %i\n", | |
323 | mfgpt_reset_timers); | |
324 | goto done; | |
325 | } | |
326 | ||
82dca611 AS |
327 | /* There are two ways to get the MFGPT base address; one is by |
328 | * fetching it from MSR_LBAR_MFGPT, the other is by reading the | |
329 | * PCI BAR info. The latter method is easier (especially across | |
330 | * different architectures), so we'll stick with that for now. If | |
331 | * it turns out to be unreliable in the face of crappy BIOSes, we | |
332 | * can always go back to using MSRs.. */ | |
333 | ||
69bc6def AS |
334 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); |
335 | if (!res) { | |
336 | dev_err(&pdev->dev, "can't fetch device resource info\n"); | |
82dca611 AS |
337 | goto done; |
338 | } | |
339 | ||
69bc6def AS |
340 | if (!request_region(res->start, resource_size(res), pdev->name)) { |
341 | dev_err(&pdev->dev, "can't request region\n"); | |
82dca611 AS |
342 | goto done; |
343 | } | |
344 | ||
345 | /* set up the driver-specific struct */ | |
69bc6def | 346 | cs5535_mfgpt_chip.base = res->start; |
82dca611 AS |
347 | cs5535_mfgpt_chip.pdev = pdev; |
348 | spin_lock_init(&cs5535_mfgpt_chip.lock); | |
349 | ||
7eb19812 | 350 | dev_info(&pdev->dev, "reserved resource region %pR\n", res); |
82dca611 AS |
351 | |
352 | /* detect the available timers */ | |
353 | t = scan_timers(&cs5535_mfgpt_chip); | |
69bc6def | 354 | dev_info(&pdev->dev, "%d MFGPT timers available\n", t); |
82dca611 AS |
355 | cs5535_mfgpt_chip.initialized = 1; |
356 | return 0; | |
357 | ||
358 | done: | |
359 | return err; | |
360 | } | |
361 | ||
853a1378 | 362 | static struct platform_driver cs5535_mfgpt_driver = { |
69bc6def AS |
363 | .driver = { |
364 | .name = DRV_NAME, | |
69bc6def AS |
365 | }, |
366 | .probe = cs5535_mfgpt_probe, | |
82dca611 | 367 | }; |
82dca611 | 368 | |
82dca611 AS |
369 | |
370 | static int __init cs5535_mfgpt_init(void) | |
371 | { | |
853a1378 | 372 | return platform_driver_register(&cs5535_mfgpt_driver); |
82dca611 AS |
373 | } |
374 | ||
375 | module_init(cs5535_mfgpt_init); | |
376 | ||
d45840d9 | 377 | MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>"); |
82dca611 AS |
378 | MODULE_DESCRIPTION("CS5535/CS5536 MFGPT timer driver"); |
379 | MODULE_LICENSE("GPL"); | |
ec9d0cf5 | 380 | MODULE_ALIAS("platform:" DRV_NAME); |