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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         struct timespec start_ts, end_ts;
149         uint64_t start, end, period;
150         unsigned int count = 0;
151 
152         /* Enable output */
153         gpcr.raw = 0;
154         gpcr.fields.dir = IOC4_GPCR_DIR_0;
155         gpcr.fields.int_out_en = 1;
156         writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
157 
158         /* Reset to power-on state */
159         writel(0, &idd->idd_misc_regs->int_out.raw);
160         mmiowb();
161 
162         /* Set up square wave */
163         int_out.raw = 0;
164         int_out.fields.count = IOC4_CALIBRATE_COUNT;
165         int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
166         int_out.fields.diag = 0;
167         writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
168         mmiowb();
169 
170         /* Check square wave period averaged over some number of cycles */
171         do {
172                 int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
173                 state = int_out.fields.int_out;
174                 if (!last_state && state) {
175                         count++;
176                         if (count == IOC4_CALIBRATE_END) {
177                                 ktime_get_ts(&end_ts);
178                                 break;
179                         } else if (count == IOC4_CALIBRATE_DISCARD)
180                                 ktime_get_ts(&start_ts);
181                 }
182                 last_state = state;
183         } while (1);
184 
185         /* Calculation rearranged to preserve intermediate precision.
186          * Logically:
187          * 1. "end - start" gives us the measurement period over all
188          *    the square wave cycles.
189          * 2. Divide by number of square wave cycles to get the period
190          *    of a square wave cycle.
191          * 3. Divide by 2*(int_out.fields.count+1), which is the formula
192          *    by which the IOC4 generates the square wave, to get the
193          *    period of an IOC4 INT_OUT count.
194          */
195         end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
196         start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
197         period = (end - start) /
198                 (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));
199 
200         /* Bounds check the result. */
201         if (period > IOC4_CALIBRATE_LOW_LIMIT ||
202             period < IOC4_CALIBRATE_HIGH_LIMIT) {
203                 printk(KERN_INFO
204                        "IOC4 %s: Clock calibration failed.  Assuming"
205                        "PCI clock is %d ns.\n",
206                        pci_name(idd->idd_pdev),
207                        IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
208                 period = IOC4_CALIBRATE_DEFAULT;
209         } else {
210                 u64 ns = period;
211 
212                 do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
213                 printk(KERN_DEBUG
214                        "IOC4 %s: PCI clock is %llu ns.\n",
215                        pci_name(idd->idd_pdev), (unsigned long long)ns);
216         }
217 
218         /* Remember results.  We store the extint clock period rather
219          * than the PCI clock period so that greater precision is
220          * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
221          * PCI clock period.
222          */
223         idd->count_period = period;
224 }
225 
226 /* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
227  * Each brings out different combinations of IOC4 signals, thus.
228  * the IOC4 subdrivers need to know to which we're attached.
229  *
230  * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
231  * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
232  * If neither is present, it's a PCI-RT.
233  */
234 static unsigned int
235 ioc4_variant(struct ioc4_driver_data *idd)
236 {
237         struct pci_dev *pdev = NULL;
238         int found = 0;
239 
240         /* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
241         do {
242                 pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
243                                       PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
244                 if (pdev &&
245                     idd->idd_pdev->bus->number == pdev->bus->number &&
246                     3 == PCI_SLOT(pdev->devfn))
247                         found = 1;
248         } while (pdev && !found);
249         if (NULL != pdev) {
250                 pci_dev_put(pdev);
251                 return IOC4_VARIANT_IO9;
252         }
253 
254         /* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
255         pdev = NULL;
256         do {
257                 pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
258                                       PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
259                 if (pdev &&
260                     idd->idd_pdev->bus->number == pdev->bus->number &&
261                     3 == PCI_SLOT(pdev->devfn))
262                         found = 1;
263         } while (pdev && !found);
264         if (NULL != pdev) {
265                 pci_dev_put(pdev);
266                 return IOC4_VARIANT_IO10;
267         }
268 
269         /* PCI-RT: No SCSI/SATA controller will be present */
270         return IOC4_VARIANT_PCI_RT;
271 }
272 
273 static void
274 ioc4_load_modules(struct work_struct *work)
275 {
276         request_module("sgiioc4");
277 }
278 
279 static DECLARE_WORK(ioc4_load_modules_work, ioc4_load_modules);
280 
281 /* Adds a new instance of an IOC4 card */
282 static int
283 ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
284 {
285         struct ioc4_driver_data *idd;
286         struct ioc4_submodule *is;
287         uint32_t pcmd;
288         int ret;
289 
290         /* Enable IOC4 and take ownership of it */
291         if ((ret = pci_enable_device(pdev))) {
292                 printk(KERN_WARNING
293                        "%s: Failed to enable IOC4 device for pci_dev %s.\n",
294                        __func__, pci_name(pdev));
295                 goto out;
296         }
297         pci_set_master(pdev);
298 
299         /* Set up per-IOC4 data */
300         idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
301         if (!idd) {
302                 printk(KERN_WARNING
303                        "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
304                        __func__, pci_name(pdev));
305                 ret = -ENODEV;
306                 goto out_idd;
307         }
308         idd->idd_pdev = pdev;
309         idd->idd_pci_id = pci_id;
310 
311         /* Map IOC4 misc registers.  These are shared between subdevices
312          * so the main IOC4 module manages them.
313          */
314         idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
315         if (!idd->idd_bar0) {
316                 printk(KERN_WARNING
317                        "%s: Unable to find IOC4 misc resource "
318                        "for pci_dev %s.\n",
319                        __func__, pci_name(idd->idd_pdev));
320                 ret = -ENODEV;
321                 goto out_pci;
322         }
323         if (!request_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
324                             "ioc4_misc")) {
325                 printk(KERN_WARNING
326                        "%s: Unable to request IOC4 misc region "
327                        "for pci_dev %s.\n",
328                        __func__, pci_name(idd->idd_pdev));
329                 ret = -ENODEV;
330                 goto out_pci;
331         }
332         idd->idd_misc_regs = ioremap(idd->idd_bar0,
333                                      sizeof(struct ioc4_misc_regs));
334         if (!idd->idd_misc_regs) {
335                 printk(KERN_WARNING
336                        "%s: Unable to remap IOC4 misc region "
337                        "for pci_dev %s.\n",
338                        __func__, pci_name(idd->idd_pdev));
339                 ret = -ENODEV;
340                 goto out_misc_region;
341         }
342 
343         /* Failsafe portion of per-IOC4 initialization */
344 
345         /* Detect card variant */
346         idd->idd_variant = ioc4_variant(idd);
347         printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
348                idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
349                idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
350                idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");
351 
352         /* Initialize IOC4 */
353         pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
354         pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
355                                pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
356 
357         /* Determine PCI clock */
358         ioc4_clock_calibrate(idd);
359 
360         /* Disable/clear all interrupts.  Need to do this here lest
361          * one submodule request the shared IOC4 IRQ, but interrupt
362          * is generated by a different subdevice.
363          */
364         /* Disable */
365         writel(~0, &idd->idd_misc_regs->other_iec.raw);
366         writel(~0, &idd->idd_misc_regs->sio_iec);
367         /* Clear (i.e. acknowledge) */
368         writel(~0, &idd->idd_misc_regs->other_ir.raw);
369         writel(~0, &idd->idd_misc_regs->sio_ir);
370 
371         /* Track PCI-device specific data */
372         idd->idd_serial_data = NULL;
373         pci_set_drvdata(idd->idd_pdev, idd);
374 
375         mutex_lock(&ioc4_mutex);
376         list_add_tail(&idd->idd_list, &ioc4_devices);
377 
378         /* Add this IOC4 to all submodules */
379         list_for_each_entry(is, &ioc4_submodules, is_list) {
380                 if (is->is_probe && is->is_probe(idd)) {
381                         printk(KERN_WARNING
382                                "%s: IOC4 submodule 0x%s probe failed "
383                                "for pci_dev %s.\n",
384                                __func__, module_name(is->is_owner),
385                                pci_name(idd->idd_pdev));
386                 }
387         }
388         mutex_unlock(&ioc4_mutex);
389 
390         /* Request sgiioc4 IDE driver on boards that bring that functionality
391          * off of IOC4.  The root filesystem may be hosted on a drive connected
392          * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
393          * won't be picked up by modprobes due to the ioc4 module owning the
394          * PCI device.
395          */
396         if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
397                 /* Request the module from a work procedure as the modprobe
398                  * goes out to a userland helper and that will hang if done
399                  * directly from ioc4_probe().
400                  */
401                 printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
402                 schedule_work(&ioc4_load_modules_work);
403         }
404 
405         return 0;
406 
407 out_misc_region:
408         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
409 out_pci:
410         kfree(idd);
411 out_idd:
412         pci_disable_device(pdev);
413 out:
414         return ret;
415 }
416 
417 /* Removes a particular instance of an IOC4 card. */
418 static void
419 ioc4_remove(struct pci_dev *pdev)
420 {
421         struct ioc4_submodule *is;
422         struct ioc4_driver_data *idd;
423 
424         idd = pci_get_drvdata(pdev);
425 
426         /* Remove this IOC4 from all submodules */
427         mutex_lock(&ioc4_mutex);
428         list_for_each_entry(is, &ioc4_submodules, is_list) {
429                 if (is->is_remove && is->is_remove(idd)) {
430                         printk(KERN_WARNING
431                                "%s: IOC4 submodule 0x%s remove failed "
432                                "for pci_dev %s.\n",
433                                __func__, module_name(is->is_owner),
434                                pci_name(idd->idd_pdev));
435                 }
436         }
437         mutex_unlock(&ioc4_mutex);
438 
439         /* Release resources */
440         iounmap(idd->idd_misc_regs);
441         if (!idd->idd_bar0) {
442                 printk(KERN_WARNING
443                        "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
444                        "Device removal may be incomplete.\n",
445                        __func__, pci_name(idd->idd_pdev));
446         }
447         release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
448 
449         /* Disable IOC4 and relinquish */
450         pci_disable_device(pdev);
451 
452         /* Remove and free driver data */
453         mutex_lock(&ioc4_mutex);
454         list_del(&idd->idd_list);
455         mutex_unlock(&ioc4_mutex);
456         kfree(idd);
457 }
458 
459 static struct pci_device_id ioc4_id_table[] = {
460         {PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
461          PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
462         {0}
463 };
464 
465 static struct pci_driver ioc4_driver = {
466         .name = "IOC4",
467         .id_table = ioc4_id_table,
468         .probe = ioc4_probe,
469         .remove = ioc4_remove,
470 };
471 
472 MODULE_DEVICE_TABLE(pci, ioc4_id_table);
473 
474 /*********************
475  * Module management *
476  *********************/
477 
478 /* Module load */
479 static int __init
480 ioc4_init(void)
481 {
482         return pci_register_driver(&ioc4_driver);
483 }
484 
485 /* Module unload */
486 static void __exit
487 ioc4_exit(void)
488 {
489         /* Ensure ioc4_load_modules() has completed before exiting */
490         flush_work(&ioc4_load_modules_work);
491         pci_unregister_driver(&ioc4_driver);
492 }
493 
494 module_init(ioc4_init);
495 module_exit(ioc4_exit);
496 
497 MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
498 MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
499 MODULE_LICENSE("GPL");
500 
501 EXPORT_SYMBOL(ioc4_register_submodule);
502 EXPORT_SYMBOL(ioc4_unregister_submodule);
503 

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