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authorLinus Torvalds <torvalds@linux-foundation.org>2011-08-03 03:16:11 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-08-03 03:16:11 -0400
commit1850536b93888e6cc3ee42e63e20e61f35f8b3e2 (patch)
tree7b78bf5196ca79f52f0fd7c932ea8062c91ff154 /drivers/char
parented8f37370d83e695c0a4fa5d5fc7a83ecb947526 (diff)
parentd1afa65ca59d4e6a5f1a8c1ab9bfa73f2fa8b777 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile/mm/init.c: trivial: use BUG_ON arch/tile: remove useless set_fixmap_nocache() macro arch/tile: add hypervisor-based character driver for SPI flash ROM ioctl-number.txt: add the tile hardwall ioctl range tile: use generic-y format for one-line asm-generic headers clocksource: tile: convert to use clocksource_register_hz
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/Kconfig11
-rw-r--r--drivers/char/Makefile2
-rw-r--r--drivers/char/tile-srom.c481
3 files changed, 494 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 49502bc5360a..423fd56bf612 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -616,5 +616,16 @@ config MSM_SMD_PKT
616 Enables userspace clients to read and write to some packet SMD 616 Enables userspace clients to read and write to some packet SMD
617 ports via device interface for MSM chipset. 617 ports via device interface for MSM chipset.
618 618
619config TILE_SROM
620 bool "Character-device access via hypervisor to the Tilera SPI ROM"
621 depends on TILE
622 default y
623 ---help---
624 This device provides character-level read-write access
625 to the SROM, typically via the "0", "1", and "2" devices
626 in /dev/srom/. The Tilera hypervisor makes the flash
627 device appear much like a simple EEPROM, and knows
628 how to partition a single ROM for multiple purposes.
629
619endmenu 630endmenu
620 631
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 7a00672bd85d..32762ba769c2 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -63,3 +63,5 @@ obj-$(CONFIG_RAMOOPS) += ramoops.o
63 63
64obj-$(CONFIG_JS_RTC) += js-rtc.o 64obj-$(CONFIG_JS_RTC) += js-rtc.o
65js-rtc-y = rtc.o 65js-rtc-y = rtc.o
66
67obj-$(CONFIG_TILE_SROM) += tile-srom.o
diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
new file mode 100644
index 000000000000..cf3ee008dca2
--- /dev/null
+++ b/drivers/char/tile-srom.c
@@ -0,0 +1,481 @@
1/*
2 * Copyright 2011 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * SPI Flash ROM driver
15 *
16 * This source code is derived from code provided in "Linux Device
17 * Drivers, Third Edition", by Jonathan Corbet, Alessandro Rubini, and
18 * Greg Kroah-Hartman, published by O'Reilly Media, Inc.
19 */
20
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/init.h>
24#include <linux/kernel.h> /* printk() */
25#include <linux/slab.h> /* kmalloc() */
26#include <linux/fs.h> /* everything... */
27#include <linux/errno.h> /* error codes */
28#include <linux/types.h> /* size_t */
29#include <linux/proc_fs.h>
30#include <linux/fcntl.h> /* O_ACCMODE */
31#include <linux/aio.h>
32#include <linux/pagemap.h>
33#include <linux/hugetlb.h>
34#include <linux/uaccess.h>
35#include <linux/platform_device.h>
36#include <hv/hypervisor.h>
37#include <linux/ioctl.h>
38#include <linux/cdev.h>
39#include <linux/delay.h>
40#include <hv/drv_srom_intf.h>
41
42/*
43 * Size of our hypervisor I/O requests. We break up large transfers
44 * so that we don't spend large uninterrupted spans of time in the
45 * hypervisor. Erasing an SROM sector takes a significant fraction of
46 * a second, so if we allowed the user to, say, do one I/O to write the
47 * entire ROM, we'd get soft lockup timeouts, or worse.
48 */
49#define SROM_CHUNK_SIZE ((size_t)4096)
50
51/*
52 * When hypervisor is busy (e.g. erasing), poll the status periodically.
53 */
54
55/*
56 * Interval to poll the state in msec
57 */
58#define SROM_WAIT_TRY_INTERVAL 20
59
60/*
61 * Maximum times to poll the state
62 */
63#define SROM_MAX_WAIT_TRY_TIMES 1000
64
65struct srom_dev {
66 int hv_devhdl; /* Handle for hypervisor device */
67 u32 total_size; /* Size of this device */
68 u32 sector_size; /* Size of a sector */
69 u32 page_size; /* Size of a page */
70 struct mutex lock; /* Allow only one accessor at a time */
71};
72
73static int srom_major; /* Dynamic major by default */
74module_param(srom_major, int, 0);
75MODULE_AUTHOR("Tilera Corporation");
76MODULE_LICENSE("GPL");
77
78static int srom_devs; /* Number of SROM partitions */
79static struct cdev srom_cdev;
80static struct class *srom_class;
81static struct srom_dev *srom_devices;
82
83/*
84 * Handle calling the hypervisor and managing EAGAIN/EBUSY.
85 */
86
87static ssize_t _srom_read(int hv_devhdl, void *buf,
88 loff_t off, size_t count)
89{
90 int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
91 for (;;) {
92 retval = hv_dev_pread(hv_devhdl, 0, (HV_VirtAddr)buf,
93 count, off);
94 if (retval >= 0)
95 return retval;
96 if (retval == HV_EAGAIN)
97 continue;
98 if (retval == HV_EBUSY && --retries > 0) {
99 msleep(SROM_WAIT_TRY_INTERVAL);
100 continue;
101 }
102 pr_err("_srom_read: error %d\n", retval);
103 return -EIO;
104 }
105}
106
107static ssize_t _srom_write(int hv_devhdl, const void *buf,
108 loff_t off, size_t count)
109{
110 int retval, retries = SROM_MAX_WAIT_TRY_TIMES;
111 for (;;) {
112 retval = hv_dev_pwrite(hv_devhdl, 0, (HV_VirtAddr)buf,
113 count, off);
114 if (retval >= 0)
115 return retval;
116 if (retval == HV_EAGAIN)
117 continue;
118 if (retval == HV_EBUSY && --retries > 0) {
119 msleep(SROM_WAIT_TRY_INTERVAL);
120 continue;
121 }
122 pr_err("_srom_write: error %d\n", retval);
123 return -EIO;
124 }
125}
126
127/**
128 * srom_open() - Device open routine.
129 * @inode: Inode for this device.
130 * @filp: File for this specific open of the device.
131 *
132 * Returns zero, or an error code.
133 */
134static int srom_open(struct inode *inode, struct file *filp)
135{
136 filp->private_data = &srom_devices[iminor(inode)];
137 return 0;
138}
139
140
141/**
142 * srom_release() - Device release routine.
143 * @inode: Inode for this device.
144 * @filp: File for this specific open of the device.
145 *
146 * Returns zero, or an error code.
147 */
148static int srom_release(struct inode *inode, struct file *filp)
149{
150 struct srom_dev *srom = filp->private_data;
151 char dummy;
152
153 /* Make sure we've flushed anything written to the ROM. */
154 mutex_lock(&srom->lock);
155 if (srom->hv_devhdl >= 0)
156 _srom_write(srom->hv_devhdl, &dummy, SROM_FLUSH_OFF, 1);
157 mutex_unlock(&srom->lock);
158
159 filp->private_data = NULL;
160
161 return 0;
162}
163
164
165/**
166 * srom_read() - Read data from the device.
167 * @filp: File for this specific open of the device.
168 * @buf: User's data buffer.
169 * @count: Number of bytes requested.
170 * @f_pos: File position.
171 *
172 * Returns number of bytes read, or an error code.
173 */
174static ssize_t srom_read(struct file *filp, char __user *buf,
175 size_t count, loff_t *f_pos)
176{
177 int retval = 0;
178 void *kernbuf;
179 struct srom_dev *srom = filp->private_data;
180
181 kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
182 if (!kernbuf)
183 return -ENOMEM;
184
185 if (mutex_lock_interruptible(&srom->lock)) {
186 retval = -ERESTARTSYS;
187 kfree(kernbuf);
188 return retval;
189 }
190
191 while (count) {
192 int hv_retval;
193 int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
194
195 hv_retval = _srom_read(srom->hv_devhdl, kernbuf,
196 *f_pos, bytes_this_pass);
197 if (hv_retval > 0) {
198 if (copy_to_user(buf, kernbuf, hv_retval) != 0) {
199 retval = -EFAULT;
200 break;
201 }
202 } else if (hv_retval <= 0) {
203 if (retval == 0)
204 retval = hv_retval;
205 break;
206 }
207
208 retval += hv_retval;
209 *f_pos += hv_retval;
210 buf += hv_retval;
211 count -= hv_retval;
212 }
213
214 mutex_unlock(&srom->lock);
215 kfree(kernbuf);
216
217 return retval;
218}
219
220/**
221 * srom_write() - Write data to the device.
222 * @filp: File for this specific open of the device.
223 * @buf: User's data buffer.
224 * @count: Number of bytes requested.
225 * @f_pos: File position.
226 *
227 * Returns number of bytes written, or an error code.
228 */
229static ssize_t srom_write(struct file *filp, const char __user *buf,
230 size_t count, loff_t *f_pos)
231{
232 int retval = 0;
233 void *kernbuf;
234 struct srom_dev *srom = filp->private_data;
235
236 kernbuf = kmalloc(SROM_CHUNK_SIZE, GFP_KERNEL);
237 if (!kernbuf)
238 return -ENOMEM;
239
240 if (mutex_lock_interruptible(&srom->lock)) {
241 retval = -ERESTARTSYS;
242 kfree(kernbuf);
243 return retval;
244 }
245
246 while (count) {
247 int hv_retval;
248 int bytes_this_pass = min(count, SROM_CHUNK_SIZE);
249
250 if (copy_from_user(kernbuf, buf, bytes_this_pass) != 0) {
251 retval = -EFAULT;
252 break;
253 }
254
255 hv_retval = _srom_write(srom->hv_devhdl, kernbuf,
256 *f_pos, bytes_this_pass);
257 if (hv_retval <= 0) {
258 if (retval == 0)
259 retval = hv_retval;
260 break;
261 }
262
263 retval += hv_retval;
264 *f_pos += hv_retval;
265 buf += hv_retval;
266 count -= hv_retval;
267 }
268
269 mutex_unlock(&srom->lock);
270 kfree(kernbuf);
271
272 return retval;
273}
274
275/* Provide our own implementation so we can use srom->total_size. */
276loff_t srom_llseek(struct file *filp, loff_t offset, int origin)
277{
278 struct srom_dev *srom = filp->private_data;
279
280 if (mutex_lock_interruptible(&srom->lock))
281 return -ERESTARTSYS;
282
283 switch (origin) {
284 case SEEK_END:
285 offset += srom->total_size;
286 break;
287 case SEEK_CUR:
288 offset += filp->f_pos;
289 break;
290 }
291
292 if (offset < 0 || offset > srom->total_size) {
293 offset = -EINVAL;
294 } else {
295 filp->f_pos = offset;
296 filp->f_version = 0;
297 }
298
299 mutex_unlock(&srom->lock);
300
301 return offset;
302}
303
304static ssize_t total_show(struct device *dev,
305 struct device_attribute *attr, char *buf)
306{
307 struct srom_dev *srom = dev_get_drvdata(dev);
308 return sprintf(buf, "%u\n", srom->total_size);
309}
310
311static ssize_t sector_show(struct device *dev,
312 struct device_attribute *attr, char *buf)
313{
314 struct srom_dev *srom = dev_get_drvdata(dev);
315 return sprintf(buf, "%u\n", srom->sector_size);
316}
317
318static ssize_t page_show(struct device *dev,
319 struct device_attribute *attr, char *buf)
320{
321 struct srom_dev *srom = dev_get_drvdata(dev);
322 return sprintf(buf, "%u\n", srom->page_size);
323}
324
325static struct device_attribute srom_dev_attrs[] = {
326 __ATTR(total_size, S_IRUGO, total_show, NULL),
327 __ATTR(sector_size, S_IRUGO, sector_show, NULL),
328 __ATTR(page_size, S_IRUGO, page_show, NULL),
329 __ATTR_NULL
330};
331
332static char *srom_devnode(struct device *dev, mode_t *mode)
333{
334 *mode = S_IRUGO | S_IWUSR;
335 return kasprintf(GFP_KERNEL, "srom/%s", dev_name(dev));
336}
337
338/*
339 * The fops
340 */
341static const struct file_operations srom_fops = {
342 .owner = THIS_MODULE,
343 .llseek = srom_llseek,
344 .read = srom_read,
345 .write = srom_write,
346 .open = srom_open,
347 .release = srom_release,
348};
349
350/**
351 * srom_setup_minor() - Initialize per-minor information.
352 * @srom: Per-device SROM state.
353 * @index: Device to set up.
354 */
355static int srom_setup_minor(struct srom_dev *srom, int index)
356{
357 struct device *dev;
358 int devhdl = srom->hv_devhdl;
359
360 mutex_init(&srom->lock);
361
362 if (_srom_read(devhdl, &srom->total_size,
363 SROM_TOTAL_SIZE_OFF, sizeof(srom->total_size)) < 0)
364 return -EIO;
365 if (_srom_read(devhdl, &srom->sector_size,
366 SROM_SECTOR_SIZE_OFF, sizeof(srom->sector_size)) < 0)
367 return -EIO;
368 if (_srom_read(devhdl, &srom->page_size,
369 SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
370 return -EIO;
371
372 dev = device_create(srom_class, &platform_bus,
373 MKDEV(srom_major, index), srom, "%d", index);
374 return IS_ERR(dev) ? PTR_ERR(dev) : 0;
375}
376
377/** srom_init() - Initialize the driver's module. */
378static int srom_init(void)
379{
380 int result, i;
381 dev_t dev = MKDEV(srom_major, 0);
382
383 /*
384 * Start with a plausible number of partitions; the krealloc() call
385 * below will yield about log(srom_devs) additional allocations.
386 */
387 srom_devices = kzalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
388
389 /* Discover the number of srom partitions. */
390 for (i = 0; ; i++) {
391 int devhdl;
392 char buf[20];
393 struct srom_dev *new_srom_devices =
394 krealloc(srom_devices, (i+1) * sizeof(struct srom_dev),
395 GFP_KERNEL | __GFP_ZERO);
396 if (!new_srom_devices) {
397 result = -ENOMEM;
398 goto fail_mem;
399 }
400 srom_devices = new_srom_devices;
401 sprintf(buf, "srom/0/%d", i);
402 devhdl = hv_dev_open((HV_VirtAddr)buf, 0);
403 if (devhdl < 0) {
404 if (devhdl != HV_ENODEV)
405 pr_notice("srom/%d: hv_dev_open failed: %d.\n",
406 i, devhdl);
407 break;
408 }
409 srom_devices[i].hv_devhdl = devhdl;
410 }
411 srom_devs = i;
412
413 /* Bail out early if we have no partitions at all. */
414 if (srom_devs == 0) {
415 result = -ENODEV;
416 goto fail_mem;
417 }
418
419 /* Register our major, and accept a dynamic number. */
420 if (srom_major)
421 result = register_chrdev_region(dev, srom_devs, "srom");
422 else {
423 result = alloc_chrdev_region(&dev, 0, srom_devs, "srom");
424 srom_major = MAJOR(dev);
425 }
426 if (result < 0)
427 goto fail_mem;
428
429 /* Register a character device. */
430 cdev_init(&srom_cdev, &srom_fops);
431 srom_cdev.owner = THIS_MODULE;
432 srom_cdev.ops = &srom_fops;
433 result = cdev_add(&srom_cdev, dev, srom_devs);
434 if (result < 0)
435 goto fail_chrdev;
436
437 /* Create a sysfs class. */
438 srom_class = class_create(THIS_MODULE, "srom");
439 if (IS_ERR(srom_class)) {
440 result = PTR_ERR(srom_class);
441 goto fail_cdev;
442 }
443 srom_class->dev_attrs = srom_dev_attrs;
444 srom_class->devnode = srom_devnode;
445
446 /* Do per-partition initialization */
447 for (i = 0; i < srom_devs; i++) {
448 result = srom_setup_minor(srom_devices + i, i);
449 if (result < 0)
450 goto fail_class;
451 }
452
453 return 0;
454
455fail_class:
456 for (i = 0; i < srom_devs; i++)
457 device_destroy(srom_class, MKDEV(srom_major, i));
458 class_destroy(srom_class);
459fail_cdev:
460 cdev_del(&srom_cdev);
461fail_chrdev:
462 unregister_chrdev_region(dev, srom_devs);
463fail_mem:
464 kfree(srom_devices);
465 return result;
466}
467
468/** srom_cleanup() - Clean up the driver's module. */
469static void srom_cleanup(void)
470{
471 int i;
472 for (i = 0; i < srom_devs; i++)
473 device_destroy(srom_class, MKDEV(srom_major, i));
474 class_destroy(srom_class);
475 cdev_del(&srom_cdev);
476 unregister_chrdev_region(MKDEV(srom_major, 0), srom_devs);
477 kfree(srom_devices);
478}
479
480module_init(srom_init);
481module_exit(srom_cleanup);