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Linux/drivers/misc/ioc4.c

  1 /*
  2  * This file is subject to the terms and conditions of the GNU General Public
  3  * License.  See the file "COPYING" in the main directory of this archive
  4  * for more details.
  5  *
  6  * Copyright (C) 2005-2006 Silicon Graphics, Inc.  All Rights Reserved.
  7  */
  8 
  9 /* This file contains the master driver module for use by SGI IOC4 subdrivers.
 10  *
 11  * It allocates any resources shared between multiple subdevices, and
 12  * provides accessor functions (where needed) and the like for those
 13  * resources.  It also provides a mechanism for the subdevice modules
 14  * to support loading and unloading.
 15  *
 16  * Non-shared resources (e.g. external interrupt A_INT_OUT register page
 17  * alias, serial port and UART registers) are handled by the subdevice
 18  * modules themselves.
 19  *
 20  * This is all necessary because IOC4 is not implemented as a multi-function
 21  * PCI device, but an amalgamation of disparate registers for several
 22  * types of device (ATA, serial, external interrupts).  The normal
 23  * resource management in the kernel doesn't have quite the right interfaces
 24  * to handle this situation (e.g. multiple modules can't claim the same
 25  * PCI ID), thus this IOC4 master module.
 26  */
 27 
 28 #include <linux/errno.h>
 29 #include <linux/module.h>
 30 #include <linux/pci.h>
 31 #include <linux/ioc4.h>
 32 #include <linux/ktime.h>
 33 #include <linux/slab.h>
 34 #include <linux/mutex.h>
 35 #include <linux/time.h>
 36 #include <asm/io.h>
 37 
 38 /***************
 39  * Definitions *
 40  ***************/
 41 
 42 /* Tweakable values */
 43 
 44 /* PCI bus speed detection/calibration */
 45 #define IOC4_CALIBRATE_COUNT 63         /* Calibration cycle period */
 46 #define IOC4_CALIBRATE_CYCLES 256       /* Average over this many cycles */
 47 #define IOC4_CALIBRATE_DISCARD 2        /* Discard first few cycles */
 48 #define IOC4_CALIBRATE_LOW_MHZ 25       /* Lower bound on bus speed sanity */
 49 #define IOC4_CALIBRATE_HIGH_MHZ 75      /* Upper bound on bus speed sanity */
 50 #define IOC4_CALIBRATE_DEFAULT_MHZ 66   /* Assumed if sanity check fails */
 51 
 52 /************************
 53  * Submodule management *
 54  ************************/
 55 
 56 static DEFINE_MUTEX(ioc4_mutex);
 57 
 58 static LIST_HEAD(ioc4_devices);
 59 static LIST_HEAD(ioc4_submodules);
 60 
 61 /* Register an IOC4 submodule */
 62 int
 63 ioc4_register_submodule(struct ioc4_submodule *is)
 64 {
 65         struct ioc4_driver_data *idd;
 66 
 67         mutex_lock(&ioc4_mutex);
 68         list_add(&is->is_list, &ioc4_submodules);
 69 
 70         /* Initialize submodule for each IOC4 */
 71         if (!is->is_probe)
 72                 goto out;
 73 
 74         list_for_each_entry(idd, &ioc4_devices, idd_list) {
 75                 if (is->is_probe(idd)) {
 76                         printk(KERN_WARNING
 77                                "%s: IOC4 submodule %s probe failed "
 78                                "for pci_dev %s",
 79                                __func__, module_name(is->is_owner),
 80                                pci_name(idd->idd_pdev));
 81                 }
 82         }
 83  out:
 84         mutex_unlock(&ioc4_mutex);
 85         return 0;
 86 }
 87 
 88 /* Unregister an IOC4 submodule */
 89 void
 90 ioc4_unregister_submodule(struct ioc4_submodule *is)
 91 {
 92         struct ioc4_driver_data *idd;
 93 
 94         mutex_lock(&ioc4_mutex);
 95         list_del(&is->is_list);
 96 
 97         /* Remove submodule for each IOC4 */
 98         if (!is->is_remove)
 99                 goto out;
100 
101         list_for_each_entry(idd, &ioc4_devices, idd_list) {
102                 if (is->is_remove(idd)) {
103                         printk(KERN_WARNING
104                                "%s: IOC4 submodule %s remove failed "
105                                "for pci_dev %s.\n",
106                                __func__, module_name(is->is_owner),
107                                pci_name(idd->idd_pdev));
108                 }
109         }
110  out:
111         mutex_unlock(&ioc4_mutex);
112 }
113 
114 /*********************
115  * Device management *
116  *********************/
117 
118 #define IOC4_CALIBRATE_LOW_LIMIT \
119         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
120 #define IOC4_CALIBRATE_HIGH_LIMIT \
121         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
122 #define IOC4_CALIBRATE_DEFAULT \
123         (1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
124 
125 #define IOC4_CALIBRATE_END \
126         (IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
127 
128 #define IOC4_INT_OUT_MODE_TOGGLE 0x7    /* Toggle INT_OUT every COUNT+1 ticks */
129 
130 /* Determines external interrupt output clock period of the PCI bus an
131  * IOC4 is attached to.  This value can be used to determine the PCI
132  * bus speed.
133  *
134  * IOC4 has a design feature that various internal timers are derived from
135  * the PCI bus clock.  This causes IOC4 device drivers to need to take the
136  * bus speed into account when setting various register values (e.g. INT_OUT
137  * register COUNT field, UART divisors, etc).  Since this information is
138  * needed by several subdrivers, it is determined by the main IOC4 driver,
139  * even though the following code utilizes external interrupt registers
140  * to perform the speed calculation.
141  */
142 static void
143 ioc4_clock_calibrate(struct ioc4_driver_data *idd)
144 {
145         union ioc4_int_out int_out;
146         union ioc4_gpcr gpcr;
147         unsigned int state, last_state = 1;
148         uint64_t start, end, period;
149         unsigned int count = 0;
150 
151         /* Enable output */
152         gpcr.raw = 0;
153         gpcr.fields.dir = IOC4_GPCR_DIR_0;
154         gpcr.fields.int_out_en = 1;
155         writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
156 
157         /* Reset to power-on state */
158         writel(0, &idd->idd_misc_regs->int_out.raw);
159         mmiowb();
160 
161         /* Set up square wave */
162         int_out.raw = 0;
163         int_out.fields.count = IOC4_CALIBRATE_COUNT;
164         int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
165         int_out.fields.diag = 0;
166         writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
167         mmiowb();
168 
169         /* Check square wave period averaged over some number of cycles */
170         do {
171                 int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
172                 state = int_out.fields.int_out;
173                 if (!last_state && state) {
174                         count++;
175                         if (count == IOC4_CALIBRATE_END) {
176                                 end = ktime_get_ns();
177                                 break;
178                         } else if (count == IOC4_CALIBRATE_DISCARD)
179                                 start = ktime_get_ns();
180                 }
181                 last_state = state;
182         } while (1);
183 
184         /* Calculation rearranged to preserve intermediate precision.
185          * Logically:
186          * 1. "end - start" gives us the measurement period over all
187          *    the square wave cycles.
188          * 2. Divide by number of square wave cycles to get the period
189          *    of a square wave cycle.
190          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
191          *    by which the IOC4 generates the square wave, to get the
192          *    period of an IOC4 INT_OUT count.
193          */
194         period = (end - start) /
195                 (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
196 
197         /* Bounds check the result. */
198         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
199             period < IOC4_CALIBRATE_HIGH_LIMIT) {
200                 printk(KERN_INFO
201                        "IOC4 %s: Clock calibration failed.  Assuming"
202                        "PCI clock is %d ns.\n",
203                        pci_name(idd->idd_pdev),
204                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
205                 period = IOC4_CALIBRATE_DEFAULT;
206         } else {
207                 u64 ns = period;
208 
209                 do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
210                 printk(KERN_DEBUG
211                        "IOC4 %s: PCI clock is %llu ns.\n",
212                        pci_name(idd->idd_pdev), (unsigned long long)ns);
213         }
214 
215         /* Remember results.  We store the extint clock period rather
216          * than the PCI clock period so that greater precision is
217          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
218          * PCI clock period.
219          */
220         idd->count_period = period;
221 }
222 
223 /* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
224  * Each brings out different combinations of IOC4 signals, thus.
225  * the IOC4 subdrivers need to know to which we're attached.
226  *
227  * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
228  * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
229  * If neither is present, it's a PCI-RT.
230  */
231 static unsigned int
232 ioc4_variant(struct ioc4_driver_data *idd)
233 {
234         struct pci_dev *pdev = NULL;
235         int found = 0;
236 
237         /* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
238         do {
239                 pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
240                                       PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
241                 if (pdev &&
242                     idd->idd_pdev->bus->number == pdev->bus->number &&
243                     3 == PCI_SLOT(pdev->devfn))
244                         found = 1;
245         } while (pdev && !found);
246         if (NULL != pdev) {
247                 pci_dev_put(pdev);
248                 return IOC4_VARIANT_IO9;
249         }
250 
251         /* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
252         pdev = NULL;
253         do {
254                 pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
255                                       PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
256                 if (pdev &&
257                     idd->idd_pdev->bus->number == pdev->bus->number &&
258                     3 == PCI_SLOT(pdev->devfn))
259                         found = 1;
260         } while (pdev && !found);
261         if (NULL != pdev) {
262                 pci_dev_put(pdev);
263                 return IOC4_VARIANT_IO10;
264         }
265 
266         /* PCI-RT: No SCSI/SATA controller will be present */
267         return IOC4_VARIANT_PCI_RT;
268 }
269 
270 static void
271 ioc4_load_modules(struct work_struct *work)
272 {
273         request_module("sgiioc4");
274 }
275 
276 static DECLARE_WORK(ioc4_load_modules_work, ioc4_load_modules);
277 
278 /* Adds a new instance of an IOC4 card */
279 static int
280 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
281 {
282         struct ioc4_driver_data *idd;
283         struct ioc4_submodule *is;
284         uint32_t pcmd;
285         int ret;
286 
287         /* Enable IOC4 and take ownership of it */
288         if ((ret = pci_enable_device(pdev))) {
289                 printk(KERN_WARNING
290                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
291                        __func__, pci_name(pdev));
292                 goto out;
293         }
294         pci_set_master(pdev);
295 
296         /* Set up per-IOC4 data */
297         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
298         if (!idd) {
299                 printk(KERN_WARNING
300                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
301                        __func__, pci_name(pdev));
302                 ret = -ENODEV;
303                 goto out_idd;
304         }
305         idd->idd_pdev = pdev;
306         idd->idd_pci_id = pci_id;
307 
308         /* Map IOC4 misc registers.  These are shared between subdevices
309          * so the main IOC4 module manages them.
310          */
311         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
312         if (!idd->idd_bar0) {
313                 printk(KERN_WARNING
314                        "%s: Unable to find IOC4 misc resource "
315                        "for pci_dev %s.\n",
316                        __func__, pci_name(idd->idd_pdev));
317                 ret = -ENODEV;
318                 goto out_pci;
319         }
320         if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
321                             "ioc4_misc")) {
322                 printk(KERN_WARNING
323                        "%s: Unable to request IOC4 misc region "
324                        "for pci_dev %s.\n",
325                        __func__, pci_name(idd->idd_pdev));
326                 ret = -ENODEV;
327                 goto out_pci;
328         }
329         idd->idd_misc_regs = ioremap(idd->idd_bar0,
330                                      sizeof(struct ioc4_misc_regs));
331         if (!idd->idd_misc_regs) {
332                 printk(KERN_WARNING
333                        "%s: Unable to remap IOC4 misc region "
334                        "for pci_dev %s.\n",
335                        __func__, pci_name(idd->idd_pdev));
336                 ret = -ENODEV;
337                 goto out_misc_region;
338         }
339 
340         /* Failsafe portion of per-IOC4 initialization */
341 
342         /* Detect card variant */
343         idd->idd_variant = ioc4_variant(idd);
344         printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
345                idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
346                idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
347                idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
348 
349         /* Initialize IOC4 */
350         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
351         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
352                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
353 
354         /* Determine PCI clock */
355         ioc4_clock_calibrate(idd);
356 
357         /* Disable/clear all interrupts.  Need to do this here lest
358          * one submodule request the shared IOC4 IRQ, but interrupt
359          * is generated by a different subdevice.
360          */
361         /* Disable */
362         writel(~0, &idd->idd_misc_regs->other_iec.raw);
363         writel(~0, &idd->idd_misc_regs->sio_iec);
364         /* Clear (i.e. acknowledge) */
365         writel(~0, &idd->idd_misc_regs->other_ir.raw);
366         writel(~0, &idd->idd_misc_regs->sio_ir);
367 
368         /* Track PCI-device specific data */
369         idd->idd_serial_data = NULL;
370         pci_set_drvdata(idd->idd_pdev, idd);
371 
372         mutex_lock(&ioc4_mutex);
373         list_add_tail(&idd->idd_list, &ioc4_devices);
374 
375         /* Add this IOC4 to all submodules */
376         list_for_each_entry(is, &ioc4_submodules, is_list) {
377                 if (is->is_probe && is->is_probe(idd)) {
378                         printk(KERN_WARNING
379                                "%s: IOC4 submodule 0x%s probe failed "
380                                "for pci_dev %s.\n",
381                                __func__, module_name(is->is_owner),
382                                pci_name(idd->idd_pdev));
383                 }
384         }
385         mutex_unlock(&ioc4_mutex);
386 
387         /* Request sgiioc4 IDE driver on boards that bring that functionality
388          * off of IOC4.  The root filesystem may be hosted on a drive connected
389          * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
390          * won't be picked up by modprobes due to the ioc4 module owning the
391          * PCI device.
392          */
393         if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
394                 /* Request the module from a work procedure as the modprobe
395                  * goes out to a userland helper and that will hang if done
396                  * directly from ioc4_probe().
397                  */
398                 printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
399                 schedule_work(&ioc4_load_modules_work);
400         }
401 
402         return 0;
403 
404 out_misc_region:
405         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
406 out_pci:
407         kfree(idd);
408 out_idd:
409         pci_disable_device(pdev);
410 out:
411         return ret;
412 }
413 
414 /* Removes a particular instance of an IOC4 card. */
415 static void
416 ioc4_remove(struct pci_dev *pdev)
417 {
418         struct ioc4_submodule *is;
419         struct ioc4_driver_data *idd;
420 
421         idd = pci_get_drvdata(pdev);
422 
423         /* Remove this IOC4 from all submodules */
424         mutex_lock(&ioc4_mutex);
425         list_for_each_entry(is, &ioc4_submodules, is_list) {
426                 if (is->is_remove && is->is_remove(idd)) {
427                         printk(KERN_WARNING
428                                "%s: IOC4 submodule 0x%s remove failed "
429                                "for pci_dev %s.\n",
430                                __func__, module_name(is->is_owner),
431                                pci_name(idd->idd_pdev));
432                 }
433         }
434         mutex_unlock(&ioc4_mutex);
435 
436         /* Release resources */
437         iounmap(idd->idd_misc_regs);
438         if (!idd->idd_bar0) {
439                 printk(KERN_WARNING
440                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
441                        "Device removal may be incomplete.\n",
442                        __func__, pci_name(idd->idd_pdev));
443         }
444         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
445 
446         /* Disable IOC4 and relinquish */
447         pci_disable_device(pdev);
448 
449         /* Remove and free driver data */
450         mutex_lock(&ioc4_mutex);
451         list_del(&idd->idd_list);
452         mutex_unlock(&ioc4_mutex);
453         kfree(idd);
454 }
455 
456 static struct pci_device_id ioc4_id_table[] = {
457         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
458          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
459         {0}
460 };
461 
462 static struct pci_driver ioc4_driver = {
463         .name = "IOC4",
464         .id_table = ioc4_id_table,
465         .probe = ioc4_probe,
466         .remove = ioc4_remove,
467 };
468 
469 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
470 
471 /*********************
472  * Module management *
473  *********************/
474 
475 /* Module load */
476 static int __init
477 ioc4_init(void)
478 {
479         return pci_register_driver(&ioc4_driver);
480 }
481 
482 /* Module unload */
483 static void __exit
484 ioc4_exit(void)
485 {
486         /* Ensure ioc4_load_modules() has completed before exiting */
487         flush_work(&ioc4_load_modules_work);
488         pci_unregister_driver(&ioc4_driver);
489 }
490 
491 module_init(ioc4_init);
492 module_exit(ioc4_exit);
493 
494 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
495 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
496 MODULE_LICENSE("GPL");
497 
498 EXPORT_SYMBOL(ioc4_register_submodule);
499 EXPORT_SYMBOL(ioc4_unregister_submodule);
500 

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