xref: /openbmc/linux/drivers/usb/host/pci-quirks.c (revision 54525552)
1 /*
2  * This file contains code to reset and initialize USB host controllers.
3  * Some of it includes work-arounds for PCI hardware and BIOS quirks.
4  * It may need to run early during booting -- before USB would normally
5  * initialize -- to ensure that Linux doesn't use any legacy modes.
6  *
7  *  Copyright (c) 1999 Martin Mares <mj@ucw.cz>
8  *  (and others)
9  */
10 
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/pci.h>
14 #include <linux/init.h>
15 #include <linux/delay.h>
16 #include <linux/acpi.h>
17 #include <linux/dmi.h>
18 #include "pci-quirks.h"
19 #include "xhci-ext-caps.h"
20 
21 
22 #define UHCI_USBLEGSUP		0xc0		/* legacy support */
23 #define UHCI_USBCMD		0		/* command register */
24 #define UHCI_USBINTR		4		/* interrupt register */
25 #define UHCI_USBLEGSUP_RWC	0x8f00		/* the R/WC bits */
26 #define UHCI_USBLEGSUP_RO	0x5040		/* R/O and reserved bits */
27 #define UHCI_USBCMD_RUN		0x0001		/* RUN/STOP bit */
28 #define UHCI_USBCMD_HCRESET	0x0002		/* Host Controller reset */
29 #define UHCI_USBCMD_EGSM	0x0008		/* Global Suspend Mode */
30 #define UHCI_USBCMD_CONFIGURE	0x0040		/* Config Flag */
31 #define UHCI_USBINTR_RESUME	0x0002		/* Resume interrupt enable */
32 
33 #define OHCI_CONTROL		0x04
34 #define OHCI_CMDSTATUS		0x08
35 #define OHCI_INTRSTATUS		0x0c
36 #define OHCI_INTRENABLE		0x10
37 #define OHCI_INTRDISABLE	0x14
38 #define OHCI_OCR		(1 << 3)	/* ownership change request */
39 #define OHCI_CTRL_RWC		(1 << 9)	/* remote wakeup connected */
40 #define OHCI_CTRL_IR		(1 << 8)	/* interrupt routing */
41 #define OHCI_INTR_OC		(1 << 30)	/* ownership change */
42 
43 #define EHCI_HCC_PARAMS		0x08		/* extended capabilities */
44 #define EHCI_USBCMD		0		/* command register */
45 #define EHCI_USBCMD_RUN		(1 << 0)	/* RUN/STOP bit */
46 #define EHCI_USBSTS		4		/* status register */
47 #define EHCI_USBSTS_HALTED	(1 << 12)	/* HCHalted bit */
48 #define EHCI_USBINTR		8		/* interrupt register */
49 #define EHCI_CONFIGFLAG		0x40		/* configured flag register */
50 #define EHCI_USBLEGSUP		0		/* legacy support register */
51 #define EHCI_USBLEGSUP_BIOS	(1 << 16)	/* BIOS semaphore */
52 #define EHCI_USBLEGSUP_OS	(1 << 24)	/* OS semaphore */
53 #define EHCI_USBLEGCTLSTS	4		/* legacy control/status */
54 #define EHCI_USBLEGCTLSTS_SOOE	(1 << 13)	/* SMI on ownership change */
55 
56 /* AMD quirk use */
57 #define	AB_REG_BAR_LOW		0xe0
58 #define	AB_REG_BAR_HIGH		0xe1
59 #define	AB_REG_BAR_SB700	0xf0
60 #define	AB_INDX(addr)		((addr) + 0x00)
61 #define	AB_DATA(addr)		((addr) + 0x04)
62 #define	AX_INDXC		0x30
63 #define	AX_DATAC		0x34
64 
65 #define	NB_PCIE_INDX_ADDR	0xe0
66 #define	NB_PCIE_INDX_DATA	0xe4
67 #define	PCIE_P_CNTL		0x10040
68 #define	BIF_NB			0x10002
69 #define	NB_PIF0_PWRDOWN_0	0x01100012
70 #define	NB_PIF0_PWRDOWN_1	0x01100013
71 
72 static struct amd_chipset_info {
73 	struct pci_dev	*nb_dev;
74 	struct pci_dev	*smbus_dev;
75 	int nb_type;
76 	int sb_type;
77 	int isoc_reqs;
78 	int probe_count;
79 	int probe_result;
80 } amd_chipset;
81 
82 static DEFINE_SPINLOCK(amd_lock);
83 
84 int usb_amd_find_chipset_info(void)
85 {
86 	u8 rev = 0;
87 	unsigned long flags;
88 	struct amd_chipset_info info;
89 	int ret;
90 
91 	spin_lock_irqsave(&amd_lock, flags);
92 
93 	/* probe only once */
94 	if (amd_chipset.probe_count > 0) {
95 		amd_chipset.probe_count++;
96 		spin_unlock_irqrestore(&amd_lock, flags);
97 		return amd_chipset.probe_result;
98 	}
99 	memset(&info, 0, sizeof(info));
100 	spin_unlock_irqrestore(&amd_lock, flags);
101 
102 	info.smbus_dev = pci_get_device(PCI_VENDOR_ID_ATI, 0x4385, NULL);
103 	if (info.smbus_dev) {
104 		rev = info.smbus_dev->revision;
105 		if (rev >= 0x40)
106 			info.sb_type = 1;
107 		else if (rev >= 0x30 && rev <= 0x3b)
108 			info.sb_type = 3;
109 	} else {
110 		info.smbus_dev = pci_get_device(PCI_VENDOR_ID_AMD,
111 						0x780b, NULL);
112 		if (!info.smbus_dev) {
113 			ret = 0;
114 			goto commit;
115 		}
116 
117 		rev = info.smbus_dev->revision;
118 		if (rev >= 0x11 && rev <= 0x18)
119 			info.sb_type = 2;
120 	}
121 
122 	if (info.sb_type == 0) {
123 		if (info.smbus_dev) {
124 			pci_dev_put(info.smbus_dev);
125 			info.smbus_dev = NULL;
126 		}
127 		ret = 0;
128 		goto commit;
129 	}
130 
131 	info.nb_dev = pci_get_device(PCI_VENDOR_ID_AMD, 0x9601, NULL);
132 	if (info.nb_dev) {
133 		info.nb_type = 1;
134 	} else {
135 		info.nb_dev = pci_get_device(PCI_VENDOR_ID_AMD, 0x1510, NULL);
136 		if (info.nb_dev) {
137 			info.nb_type = 2;
138 		} else {
139 			info.nb_dev = pci_get_device(PCI_VENDOR_ID_AMD,
140 						     0x9600, NULL);
141 			if (info.nb_dev)
142 				info.nb_type = 3;
143 		}
144 	}
145 
146 	ret = info.probe_result = 1;
147 	printk(KERN_DEBUG "QUIRK: Enable AMD PLL fix\n");
148 
149 commit:
150 
151 	spin_lock_irqsave(&amd_lock, flags);
152 	if (amd_chipset.probe_count > 0) {
153 		/* race - someone else was faster - drop devices */
154 
155 		/* Mark that we where here */
156 		amd_chipset.probe_count++;
157 		ret = amd_chipset.probe_result;
158 
159 		spin_unlock_irqrestore(&amd_lock, flags);
160 
161 		if (info.nb_dev)
162 			pci_dev_put(info.nb_dev);
163 		if (info.smbus_dev)
164 			pci_dev_put(info.smbus_dev);
165 
166 	} else {
167 		/* no race - commit the result */
168 		info.probe_count++;
169 		amd_chipset = info;
170 		spin_unlock_irqrestore(&amd_lock, flags);
171 	}
172 
173 	return ret;
174 }
175 EXPORT_SYMBOL_GPL(usb_amd_find_chipset_info);
176 
177 /*
178  * The hardware normally enables the A-link power management feature, which
179  * lets the system lower the power consumption in idle states.
180  *
181  * This USB quirk prevents the link going into that lower power state
182  * during isochronous transfers.
183  *
184  * Without this quirk, isochronous stream on OHCI/EHCI/xHCI controllers of
185  * some AMD platforms may stutter or have breaks occasionally.
186  */
187 static void usb_amd_quirk_pll(int disable)
188 {
189 	u32 addr, addr_low, addr_high, val;
190 	u32 bit = disable ? 0 : 1;
191 	unsigned long flags;
192 
193 	spin_lock_irqsave(&amd_lock, flags);
194 
195 	if (disable) {
196 		amd_chipset.isoc_reqs++;
197 		if (amd_chipset.isoc_reqs > 1) {
198 			spin_unlock_irqrestore(&amd_lock, flags);
199 			return;
200 		}
201 	} else {
202 		amd_chipset.isoc_reqs--;
203 		if (amd_chipset.isoc_reqs > 0) {
204 			spin_unlock_irqrestore(&amd_lock, flags);
205 			return;
206 		}
207 	}
208 
209 	if (amd_chipset.sb_type == 1 || amd_chipset.sb_type == 2) {
210 		outb_p(AB_REG_BAR_LOW, 0xcd6);
211 		addr_low = inb_p(0xcd7);
212 		outb_p(AB_REG_BAR_HIGH, 0xcd6);
213 		addr_high = inb_p(0xcd7);
214 		addr = addr_high << 8 | addr_low;
215 
216 		outl_p(0x30, AB_INDX(addr));
217 		outl_p(0x40, AB_DATA(addr));
218 		outl_p(0x34, AB_INDX(addr));
219 		val = inl_p(AB_DATA(addr));
220 	} else if (amd_chipset.sb_type == 3) {
221 		pci_read_config_dword(amd_chipset.smbus_dev,
222 					AB_REG_BAR_SB700, &addr);
223 		outl(AX_INDXC, AB_INDX(addr));
224 		outl(0x40, AB_DATA(addr));
225 		outl(AX_DATAC, AB_INDX(addr));
226 		val = inl(AB_DATA(addr));
227 	} else {
228 		spin_unlock_irqrestore(&amd_lock, flags);
229 		return;
230 	}
231 
232 	if (disable) {
233 		val &= ~0x08;
234 		val |= (1 << 4) | (1 << 9);
235 	} else {
236 		val |= 0x08;
237 		val &= ~((1 << 4) | (1 << 9));
238 	}
239 	outl_p(val, AB_DATA(addr));
240 
241 	if (!amd_chipset.nb_dev) {
242 		spin_unlock_irqrestore(&amd_lock, flags);
243 		return;
244 	}
245 
246 	if (amd_chipset.nb_type == 1 || amd_chipset.nb_type == 3) {
247 		addr = PCIE_P_CNTL;
248 		pci_write_config_dword(amd_chipset.nb_dev,
249 					NB_PCIE_INDX_ADDR, addr);
250 		pci_read_config_dword(amd_chipset.nb_dev,
251 					NB_PCIE_INDX_DATA, &val);
252 
253 		val &= ~(1 | (1 << 3) | (1 << 4) | (1 << 9) | (1 << 12));
254 		val |= bit | (bit << 3) | (bit << 12);
255 		val |= ((!bit) << 4) | ((!bit) << 9);
256 		pci_write_config_dword(amd_chipset.nb_dev,
257 					NB_PCIE_INDX_DATA, val);
258 
259 		addr = BIF_NB;
260 		pci_write_config_dword(amd_chipset.nb_dev,
261 					NB_PCIE_INDX_ADDR, addr);
262 		pci_read_config_dword(amd_chipset.nb_dev,
263 					NB_PCIE_INDX_DATA, &val);
264 		val &= ~(1 << 8);
265 		val |= bit << 8;
266 
267 		pci_write_config_dword(amd_chipset.nb_dev,
268 					NB_PCIE_INDX_DATA, val);
269 	} else if (amd_chipset.nb_type == 2) {
270 		addr = NB_PIF0_PWRDOWN_0;
271 		pci_write_config_dword(amd_chipset.nb_dev,
272 					NB_PCIE_INDX_ADDR, addr);
273 		pci_read_config_dword(amd_chipset.nb_dev,
274 					NB_PCIE_INDX_DATA, &val);
275 		if (disable)
276 			val &= ~(0x3f << 7);
277 		else
278 			val |= 0x3f << 7;
279 
280 		pci_write_config_dword(amd_chipset.nb_dev,
281 					NB_PCIE_INDX_DATA, val);
282 
283 		addr = NB_PIF0_PWRDOWN_1;
284 		pci_write_config_dword(amd_chipset.nb_dev,
285 					NB_PCIE_INDX_ADDR, addr);
286 		pci_read_config_dword(amd_chipset.nb_dev,
287 					NB_PCIE_INDX_DATA, &val);
288 		if (disable)
289 			val &= ~(0x3f << 7);
290 		else
291 			val |= 0x3f << 7;
292 
293 		pci_write_config_dword(amd_chipset.nb_dev,
294 					NB_PCIE_INDX_DATA, val);
295 	}
296 
297 	spin_unlock_irqrestore(&amd_lock, flags);
298 	return;
299 }
300 
301 void usb_amd_quirk_pll_disable(void)
302 {
303 	usb_amd_quirk_pll(1);
304 }
305 EXPORT_SYMBOL_GPL(usb_amd_quirk_pll_disable);
306 
307 void usb_amd_quirk_pll_enable(void)
308 {
309 	usb_amd_quirk_pll(0);
310 }
311 EXPORT_SYMBOL_GPL(usb_amd_quirk_pll_enable);
312 
313 void usb_amd_dev_put(void)
314 {
315 	struct pci_dev *nb, *smbus;
316 	unsigned long flags;
317 
318 	spin_lock_irqsave(&amd_lock, flags);
319 
320 	amd_chipset.probe_count--;
321 	if (amd_chipset.probe_count > 0) {
322 		spin_unlock_irqrestore(&amd_lock, flags);
323 		return;
324 	}
325 
326 	/* save them to pci_dev_put outside of spinlock */
327 	nb    = amd_chipset.nb_dev;
328 	smbus = amd_chipset.smbus_dev;
329 
330 	amd_chipset.nb_dev = NULL;
331 	amd_chipset.smbus_dev = NULL;
332 	amd_chipset.nb_type = 0;
333 	amd_chipset.sb_type = 0;
334 	amd_chipset.isoc_reqs = 0;
335 	amd_chipset.probe_result = 0;
336 
337 	spin_unlock_irqrestore(&amd_lock, flags);
338 
339 	if (nb)
340 		pci_dev_put(nb);
341 	if (smbus)
342 		pci_dev_put(smbus);
343 }
344 EXPORT_SYMBOL_GPL(usb_amd_dev_put);
345 
346 /*
347  * Make sure the controller is completely inactive, unable to
348  * generate interrupts or do DMA.
349  */
350 void uhci_reset_hc(struct pci_dev *pdev, unsigned long base)
351 {
352 	/* Turn off PIRQ enable and SMI enable.  (This also turns off the
353 	 * BIOS's USB Legacy Support.)  Turn off all the R/WC bits too.
354 	 */
355 	pci_write_config_word(pdev, UHCI_USBLEGSUP, UHCI_USBLEGSUP_RWC);
356 
357 	/* Reset the HC - this will force us to get a
358 	 * new notification of any already connected
359 	 * ports due to the virtual disconnect that it
360 	 * implies.
361 	 */
362 	outw(UHCI_USBCMD_HCRESET, base + UHCI_USBCMD);
363 	mb();
364 	udelay(5);
365 	if (inw(base + UHCI_USBCMD) & UHCI_USBCMD_HCRESET)
366 		dev_warn(&pdev->dev, "HCRESET not completed yet!\n");
367 
368 	/* Just to be safe, disable interrupt requests and
369 	 * make sure the controller is stopped.
370 	 */
371 	outw(0, base + UHCI_USBINTR);
372 	outw(0, base + UHCI_USBCMD);
373 }
374 EXPORT_SYMBOL_GPL(uhci_reset_hc);
375 
376 /*
377  * Initialize a controller that was newly discovered or has just been
378  * resumed.  In either case we can't be sure of its previous state.
379  *
380  * Returns: 1 if the controller was reset, 0 otherwise.
381  */
382 int uhci_check_and_reset_hc(struct pci_dev *pdev, unsigned long base)
383 {
384 	u16 legsup;
385 	unsigned int cmd, intr;
386 
387 	/*
388 	 * When restarting a suspended controller, we expect all the
389 	 * settings to be the same as we left them:
390 	 *
391 	 *	PIRQ and SMI disabled, no R/W bits set in USBLEGSUP;
392 	 *	Controller is stopped and configured with EGSM set;
393 	 *	No interrupts enabled except possibly Resume Detect.
394 	 *
395 	 * If any of these conditions are violated we do a complete reset.
396 	 */
397 	pci_read_config_word(pdev, UHCI_USBLEGSUP, &legsup);
398 	if (legsup & ~(UHCI_USBLEGSUP_RO | UHCI_USBLEGSUP_RWC)) {
399 		dev_dbg(&pdev->dev, "%s: legsup = 0x%04x\n",
400 				__func__, legsup);
401 		goto reset_needed;
402 	}
403 
404 	cmd = inw(base + UHCI_USBCMD);
405 	if ((cmd & UHCI_USBCMD_RUN) || !(cmd & UHCI_USBCMD_CONFIGURE) ||
406 			!(cmd & UHCI_USBCMD_EGSM)) {
407 		dev_dbg(&pdev->dev, "%s: cmd = 0x%04x\n",
408 				__func__, cmd);
409 		goto reset_needed;
410 	}
411 
412 	intr = inw(base + UHCI_USBINTR);
413 	if (intr & (~UHCI_USBINTR_RESUME)) {
414 		dev_dbg(&pdev->dev, "%s: intr = 0x%04x\n",
415 				__func__, intr);
416 		goto reset_needed;
417 	}
418 	return 0;
419 
420 reset_needed:
421 	dev_dbg(&pdev->dev, "Performing full reset\n");
422 	uhci_reset_hc(pdev, base);
423 	return 1;
424 }
425 EXPORT_SYMBOL_GPL(uhci_check_and_reset_hc);
426 
427 static inline int io_type_enabled(struct pci_dev *pdev, unsigned int mask)
428 {
429 	u16 cmd;
430 	return !pci_read_config_word(pdev, PCI_COMMAND, &cmd) && (cmd & mask);
431 }
432 
433 #define pio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_IO)
434 #define mmio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_MEMORY)
435 
436 static void __devinit quirk_usb_handoff_uhci(struct pci_dev *pdev)
437 {
438 	unsigned long base = 0;
439 	int i;
440 
441 	if (!pio_enabled(pdev))
442 		return;
443 
444 	for (i = 0; i < PCI_ROM_RESOURCE; i++)
445 		if ((pci_resource_flags(pdev, i) & IORESOURCE_IO)) {
446 			base = pci_resource_start(pdev, i);
447 			break;
448 		}
449 
450 	if (base)
451 		uhci_check_and_reset_hc(pdev, base);
452 }
453 
454 static int __devinit mmio_resource_enabled(struct pci_dev *pdev, int idx)
455 {
456 	return pci_resource_start(pdev, idx) && mmio_enabled(pdev);
457 }
458 
459 static void __devinit quirk_usb_handoff_ohci(struct pci_dev *pdev)
460 {
461 	void __iomem *base;
462 	u32 control;
463 
464 	if (!mmio_resource_enabled(pdev, 0))
465 		return;
466 
467 	base = pci_ioremap_bar(pdev, 0);
468 	if (base == NULL)
469 		return;
470 
471 	control = readl(base + OHCI_CONTROL);
472 
473 /* On PA-RISC, PDC can leave IR set incorrectly; ignore it there. */
474 #ifdef __hppa__
475 #define	OHCI_CTRL_MASK		(OHCI_CTRL_RWC | OHCI_CTRL_IR)
476 #else
477 #define	OHCI_CTRL_MASK		OHCI_CTRL_RWC
478 
479 	if (control & OHCI_CTRL_IR) {
480 		int wait_time = 500; /* arbitrary; 5 seconds */
481 		writel(OHCI_INTR_OC, base + OHCI_INTRENABLE);
482 		writel(OHCI_OCR, base + OHCI_CMDSTATUS);
483 		while (wait_time > 0 &&
484 				readl(base + OHCI_CONTROL) & OHCI_CTRL_IR) {
485 			wait_time -= 10;
486 			msleep(10);
487 		}
488 		if (wait_time <= 0)
489 			dev_warn(&pdev->dev, "OHCI: BIOS handoff failed"
490 					" (BIOS bug?) %08x\n",
491 					readl(base + OHCI_CONTROL));
492 	}
493 #endif
494 
495 	/* reset controller, preserving RWC (and possibly IR) */
496 	writel(control & OHCI_CTRL_MASK, base + OHCI_CONTROL);
497 
498 	/*
499 	 * disable interrupts
500 	 */
501 	writel(~(u32)0, base + OHCI_INTRDISABLE);
502 	writel(~(u32)0, base + OHCI_INTRSTATUS);
503 
504 	iounmap(base);
505 }
506 
507 static void __devinit ehci_bios_handoff(struct pci_dev *pdev,
508 					void __iomem *op_reg_base,
509 					u32 cap, u8 offset)
510 {
511 	int try_handoff = 1, tried_handoff = 0;
512 
513 	/* The Pegatron Lucid (ExoPC) tablet sporadically waits for 90
514 	 * seconds trying the handoff on its unused controller.  Skip
515 	 * it. */
516 	if (pdev->vendor == 0x8086 && pdev->device == 0x283a) {
517 		const char *dmi_bn = dmi_get_system_info(DMI_BOARD_NAME);
518 		const char *dmi_bv = dmi_get_system_info(DMI_BIOS_VERSION);
519 		if (dmi_bn && !strcmp(dmi_bn, "EXOPG06411") &&
520 		    dmi_bv && !strcmp(dmi_bv, "Lucid-CE-133"))
521 			try_handoff = 0;
522 	}
523 
524 	if (try_handoff && (cap & EHCI_USBLEGSUP_BIOS)) {
525 		dev_dbg(&pdev->dev, "EHCI: BIOS handoff\n");
526 
527 #if 0
528 /* aleksey_gorelov@phoenix.com reports that some systems need SMI forced on,
529  * but that seems dubious in general (the BIOS left it off intentionally)
530  * and is known to prevent some systems from booting.  so we won't do this
531  * unless maybe we can determine when we're on a system that needs SMI forced.
532  */
533 		/* BIOS workaround (?): be sure the pre-Linux code
534 		 * receives the SMI
535 		 */
536 		pci_read_config_dword(pdev, offset + EHCI_USBLEGCTLSTS, &val);
537 		pci_write_config_dword(pdev, offset + EHCI_USBLEGCTLSTS,
538 				       val | EHCI_USBLEGCTLSTS_SOOE);
539 #endif
540 
541 		/* some systems get upset if this semaphore is
542 		 * set for any other reason than forcing a BIOS
543 		 * handoff..
544 		 */
545 		pci_write_config_byte(pdev, offset + 3, 1);
546 	}
547 
548 	/* if boot firmware now owns EHCI, spin till it hands it over. */
549 	if (try_handoff) {
550 		int msec = 1000;
551 		while ((cap & EHCI_USBLEGSUP_BIOS) && (msec > 0)) {
552 			tried_handoff = 1;
553 			msleep(10);
554 			msec -= 10;
555 			pci_read_config_dword(pdev, offset, &cap);
556 		}
557 	}
558 
559 	if (cap & EHCI_USBLEGSUP_BIOS) {
560 		/* well, possibly buggy BIOS... try to shut it down,
561 		 * and hope nothing goes too wrong
562 		 */
563 		if (try_handoff)
564 			dev_warn(&pdev->dev, "EHCI: BIOS handoff failed"
565 				 " (BIOS bug?) %08x\n", cap);
566 		pci_write_config_byte(pdev, offset + 2, 0);
567 	}
568 
569 	/* just in case, always disable EHCI SMIs */
570 	pci_write_config_dword(pdev, offset + EHCI_USBLEGCTLSTS, 0);
571 
572 	/* If the BIOS ever owned the controller then we can't expect
573 	 * any power sessions to remain intact.
574 	 */
575 	if (tried_handoff)
576 		writel(0, op_reg_base + EHCI_CONFIGFLAG);
577 }
578 
579 static void __devinit quirk_usb_disable_ehci(struct pci_dev *pdev)
580 {
581 	void __iomem *base, *op_reg_base;
582 	u32	hcc_params, cap, val;
583 	u8	offset, cap_length;
584 	int	wait_time, delta, count = 256/4;
585 
586 	if (!mmio_resource_enabled(pdev, 0))
587 		return;
588 
589 	base = pci_ioremap_bar(pdev, 0);
590 	if (base == NULL)
591 		return;
592 
593 	cap_length = readb(base);
594 	op_reg_base = base + cap_length;
595 
596 	/* EHCI 0.96 and later may have "extended capabilities"
597 	 * spec section 5.1 explains the bios handoff, e.g. for
598 	 * booting from USB disk or using a usb keyboard
599 	 */
600 	hcc_params = readl(base + EHCI_HCC_PARAMS);
601 	offset = (hcc_params >> 8) & 0xff;
602 	while (offset && --count) {
603 		pci_read_config_dword(pdev, offset, &cap);
604 
605 		switch (cap & 0xff) {
606 		case 1:
607 			ehci_bios_handoff(pdev, op_reg_base, cap, offset);
608 			break;
609 		case 0: /* Illegal reserved cap, set cap=0 so we exit */
610 			cap = 0; /* then fallthrough... */
611 		default:
612 			dev_warn(&pdev->dev, "EHCI: unrecognized capability "
613 				 "%02x\n", cap & 0xff);
614 		}
615 		offset = (cap >> 8) & 0xff;
616 	}
617 	if (!count)
618 		dev_printk(KERN_DEBUG, &pdev->dev, "EHCI: capability loop?\n");
619 
620 	/*
621 	 * halt EHCI & disable its interrupts in any case
622 	 */
623 	val = readl(op_reg_base + EHCI_USBSTS);
624 	if ((val & EHCI_USBSTS_HALTED) == 0) {
625 		val = readl(op_reg_base + EHCI_USBCMD);
626 		val &= ~EHCI_USBCMD_RUN;
627 		writel(val, op_reg_base + EHCI_USBCMD);
628 
629 		wait_time = 2000;
630 		delta = 100;
631 		do {
632 			writel(0x3f, op_reg_base + EHCI_USBSTS);
633 			udelay(delta);
634 			wait_time -= delta;
635 			val = readl(op_reg_base + EHCI_USBSTS);
636 			if ((val == ~(u32)0) || (val & EHCI_USBSTS_HALTED)) {
637 				break;
638 			}
639 		} while (wait_time > 0);
640 	}
641 	writel(0, op_reg_base + EHCI_USBINTR);
642 	writel(0x3f, op_reg_base + EHCI_USBSTS);
643 
644 	iounmap(base);
645 }
646 
647 /*
648  * handshake - spin reading a register until handshake completes
649  * @ptr: address of hc register to be read
650  * @mask: bits to look at in result of read
651  * @done: value of those bits when handshake succeeds
652  * @wait_usec: timeout in microseconds
653  * @delay_usec: delay in microseconds to wait between polling
654  *
655  * Polls a register every delay_usec microseconds.
656  * Returns 0 when the mask bits have the value done.
657  * Returns -ETIMEDOUT if this condition is not true after
658  * wait_usec microseconds have passed.
659  */
660 static int handshake(void __iomem *ptr, u32 mask, u32 done,
661 		int wait_usec, int delay_usec)
662 {
663 	u32	result;
664 
665 	do {
666 		result = readl(ptr);
667 		result &= mask;
668 		if (result == done)
669 			return 0;
670 		udelay(delay_usec);
671 		wait_usec -= delay_usec;
672 	} while (wait_usec > 0);
673 	return -ETIMEDOUT;
674 }
675 
676 /**
677  * PCI Quirks for xHCI.
678  *
679  * Takes care of the handoff between the Pre-OS (i.e. BIOS) and the OS.
680  * It signals to the BIOS that the OS wants control of the host controller,
681  * and then waits 5 seconds for the BIOS to hand over control.
682  * If we timeout, assume the BIOS is broken and take control anyway.
683  */
684 static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
685 {
686 	void __iomem *base;
687 	int ext_cap_offset;
688 	void __iomem *op_reg_base;
689 	u32 val;
690 	int timeout;
691 
692 	if (!mmio_resource_enabled(pdev, 0))
693 		return;
694 
695 	base = ioremap_nocache(pci_resource_start(pdev, 0),
696 				pci_resource_len(pdev, 0));
697 	if (base == NULL)
698 		return;
699 
700 	/*
701 	 * Find the Legacy Support Capability register -
702 	 * this is optional for xHCI host controllers.
703 	 */
704 	ext_cap_offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
705 	do {
706 		if (!ext_cap_offset)
707 			/* We've reached the end of the extended capabilities */
708 			goto hc_init;
709 		val = readl(base + ext_cap_offset);
710 		if (XHCI_EXT_CAPS_ID(val) == XHCI_EXT_CAPS_LEGACY)
711 			break;
712 		ext_cap_offset = xhci_find_next_cap_offset(base, ext_cap_offset);
713 	} while (1);
714 
715 	/* If the BIOS owns the HC, signal that the OS wants it, and wait */
716 	if (val & XHCI_HC_BIOS_OWNED) {
717 		writel(val & XHCI_HC_OS_OWNED, base + ext_cap_offset);
718 
719 		/* Wait for 5 seconds with 10 microsecond polling interval */
720 		timeout = handshake(base + ext_cap_offset, XHCI_HC_BIOS_OWNED,
721 				0, 5000, 10);
722 
723 		/* Assume a buggy BIOS and take HC ownership anyway */
724 		if (timeout) {
725 			dev_warn(&pdev->dev, "xHCI BIOS handoff failed"
726 					" (BIOS bug ?) %08x\n", val);
727 			writel(val & ~XHCI_HC_BIOS_OWNED, base + ext_cap_offset);
728 		}
729 	}
730 
731 	/* Disable any BIOS SMIs */
732 	writel(XHCI_LEGACY_DISABLE_SMI,
733 			base + ext_cap_offset + XHCI_LEGACY_CONTROL_OFFSET);
734 
735 hc_init:
736 	op_reg_base = base + XHCI_HC_LENGTH(readl(base));
737 
738 	/* Wait for the host controller to be ready before writing any
739 	 * operational or runtime registers.  Wait 5 seconds and no more.
740 	 */
741 	timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_CNR, 0,
742 			5000, 10);
743 	/* Assume a buggy HC and start HC initialization anyway */
744 	if (timeout) {
745 		val = readl(op_reg_base + XHCI_STS_OFFSET);
746 		dev_warn(&pdev->dev,
747 				"xHCI HW not ready after 5 sec (HC bug?) "
748 				"status = 0x%x\n", val);
749 	}
750 
751 	/* Send the halt and disable interrupts command */
752 	val = readl(op_reg_base + XHCI_CMD_OFFSET);
753 	val &= ~(XHCI_CMD_RUN | XHCI_IRQS);
754 	writel(val, op_reg_base + XHCI_CMD_OFFSET);
755 
756 	/* Wait for the HC to halt - poll every 125 usec (one microframe). */
757 	timeout = handshake(op_reg_base + XHCI_STS_OFFSET, XHCI_STS_HALT, 1,
758 			XHCI_MAX_HALT_USEC, 125);
759 	if (timeout) {
760 		val = readl(op_reg_base + XHCI_STS_OFFSET);
761 		dev_warn(&pdev->dev,
762 				"xHCI HW did not halt within %d usec "
763 				"status = 0x%x\n", XHCI_MAX_HALT_USEC, val);
764 	}
765 
766 	iounmap(base);
767 }
768 
769 static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
770 {
771 	if (pdev->class == PCI_CLASS_SERIAL_USB_UHCI)
772 		quirk_usb_handoff_uhci(pdev);
773 	else if (pdev->class == PCI_CLASS_SERIAL_USB_OHCI)
774 		quirk_usb_handoff_ohci(pdev);
775 	else if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
776 		quirk_usb_disable_ehci(pdev);
777 	else if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI)
778 		quirk_usb_handoff_xhci(pdev);
779 }
780 DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);
781