1 /*
2 * (C) Copyright IBM Deutschland Entwicklung GmbH 2006
3 *
4 * Author: Maxim Shchetynin <maxim@de.ibm.com>
5 *
6 * Axon DDR2 device driver.
7 * It registers one block device per Axon's DDR2 memory bank found on a system.
8 * Block devices are called axonram?, their major and minor numbers are
9 * available in /proc/devices, /proc/partitions or in /sys/block/axonram?/dev.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
14 * any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26 #include <linux/bio.h>
27 #include <linux/blkdev.h>
28 #include <linux/device.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/genhd.h>
32 #include <linux/interrupt.h>
33 #include <linux/io.h>
34 #include <linux/ioport.h>
35 #include <linux/irq.h>
36 #include <linux/irqreturn.h>
37 #include <linux/kernel.h>
38 #include <linux/mm.h>
39 #include <linux/mod_devicetable.h>
40 #include <linux/module.h>
41 #include <linux/slab.h>
42 #include <linux/string.h>
43 #include <linux/types.h>
44 #include <linux/of_device.h>
45 #include <linux/of_platform.h>
46
47 #include <asm/page.h>
48 #include <asm/prom.h>
49
50 #define AXON_RAM_MODULE_NAME "axonram"
51 #define AXON_RAM_DEVICE_NAME "axonram"
52 #define AXON_RAM_MINORS_PER_DISK 16
53 #define AXON_RAM_BLOCK_SHIFT PAGE_SHIFT
54 #define AXON_RAM_BLOCK_SIZE 1 << AXON_RAM_BLOCK_SHIFT
55 #define AXON_RAM_SECTOR_SHIFT 9
56 #define AXON_RAM_SECTOR_SIZE 1 << AXON_RAM_SECTOR_SHIFT
57 #define AXON_RAM_IRQ_FLAGS IRQF_SHARED | IRQF_TRIGGER_RISING
58
59 static int azfs_major, azfs_minor;
60
61 struct axon_ram_bank {
62 struct platform_device *device;
63 struct gendisk *disk;
64 unsigned int irq_id;
65 unsigned long ph_addr;
66 unsigned long io_addr;
67 unsigned long size;
68 unsigned long ecc_counter;
69 };
70
71 static ssize_t
axon_ram_sysfs_ecc(struct device * dev,struct device_attribute * attr,char * buf)72 axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
73 {
74 struct platform_device *device = to_platform_device(dev);
75 struct axon_ram_bank *bank = device->dev.platform_data;
76
77 BUG_ON(!bank);
78
79 return sprintf(buf, "%ld\n", bank->ecc_counter);
80 }
81
82 static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
83
84 /**
85 * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
86 * @irq: interrupt ID
87 * @dev: pointer to of_device
88 */
89 static irqreturn_t
axon_ram_irq_handler(int irq,void * dev)90 axon_ram_irq_handler(int irq, void *dev)
91 {
92 struct platform_device *device = dev;
93 struct axon_ram_bank *bank = device->dev.platform_data;
94
95 BUG_ON(!bank);
96
97 dev_err(&device->dev, "Correctable memory error occurred\n");
98 bank->ecc_counter++;
99 return IRQ_HANDLED;
100 }
101
102 /**
103 * axon_ram_make_request - make_request() method for block device
104 * @queue, @bio: see blk_queue_make_request()
105 */
106 static void
axon_ram_make_request(struct request_queue * queue,struct bio * bio)107 axon_ram_make_request(struct request_queue *queue, struct bio *bio)
108 {
109 struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
110 unsigned long phys_mem, phys_end;
111 void *user_mem;
112 struct bio_vec *vec;
113 unsigned int transfered;
114 unsigned short idx;
115
116 phys_mem = bank->io_addr + (bio->bi_sector << AXON_RAM_SECTOR_SHIFT);
117 phys_end = bank->io_addr + bank->size;
118 transfered = 0;
119 bio_for_each_segment(vec, bio, idx) {
120 if (unlikely(phys_mem + vec->bv_len > phys_end)) {
121 bio_io_error(bio);
122 return;
123 }
124
125 user_mem = page_address(vec->bv_page) + vec->bv_offset;
126 if (bio_data_dir(bio) == READ)
127 memcpy(user_mem, (void *) phys_mem, vec->bv_len);
128 else
129 memcpy((void *) phys_mem, user_mem, vec->bv_len);
130
131 phys_mem += vec->bv_len;
132 transfered += vec->bv_len;
133 }
134 bio_endio(bio, 0);
135 }
136
137 /**
138 * axon_ram_direct_access - direct_access() method for block device
139 * @device, @sector, @data: see block_device_operations method
140 */
141 static int
axon_ram_direct_access(struct block_device * device,sector_t sector,void ** kaddr,unsigned long * pfn)142 axon_ram_direct_access(struct block_device *device, sector_t sector,
143 void **kaddr, unsigned long *pfn)
144 {
145 struct axon_ram_bank *bank = device->bd_disk->private_data;
146 loff_t offset;
147
148 offset = sector;
149 if (device->bd_part != NULL)
150 offset += device->bd_part->start_sect;
151 offset <<= AXON_RAM_SECTOR_SHIFT;
152 if (offset >= bank->size) {
153 dev_err(&bank->device->dev, "Access outside of address space\n");
154 return -ERANGE;
155 }
156
157 *kaddr = (void *)(bank->ph_addr + offset);
158 *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
159
160 return 0;
161 }
162
163 static const struct block_device_operations axon_ram_devops = {
164 .owner = THIS_MODULE,
165 .direct_access = axon_ram_direct_access
166 };
167
168 /**
169 * axon_ram_probe - probe() method for platform driver
170 * @device: see platform_driver method
171 */
axon_ram_probe(struct platform_device * device)172 static int axon_ram_probe(struct platform_device *device)
173 {
174 static int axon_ram_bank_id = -1;
175 struct axon_ram_bank *bank;
176 struct resource resource;
177 int rc = 0;
178
179 axon_ram_bank_id++;
180
181 dev_info(&device->dev, "Found memory controller on %s\n",
182 device->dev.of_node->full_name);
183
184 bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
185 if (bank == NULL) {
186 dev_err(&device->dev, "Out of memory\n");
187 rc = -ENOMEM;
188 goto failed;
189 }
190
191 device->dev.platform_data = bank;
192
193 bank->device = device;
194
195 if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
196 dev_err(&device->dev, "Cannot access device tree\n");
197 rc = -EFAULT;
198 goto failed;
199 }
200
201 bank->size = resource_size(&resource);
202
203 if (bank->size == 0) {
204 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
205 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
206 rc = -ENODEV;
207 goto failed;
208 }
209
210 dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
211 AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
212
213 bank->ph_addr = resource.start;
214 bank->io_addr = (unsigned long) ioremap_prot(
215 bank->ph_addr, bank->size, _PAGE_NO_CACHE);
216 if (bank->io_addr == 0) {
217 dev_err(&device->dev, "ioremap() failed\n");
218 rc = -EFAULT;
219 goto failed;
220 }
221
222 bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
223 if (bank->disk == NULL) {
224 dev_err(&device->dev, "Cannot register disk\n");
225 rc = -EFAULT;
226 goto failed;
227 }
228
229 bank->disk->major = azfs_major;
230 bank->disk->first_minor = azfs_minor;
231 bank->disk->fops = &axon_ram_devops;
232 bank->disk->private_data = bank;
233 bank->disk->driverfs_dev = &device->dev;
234
235 sprintf(bank->disk->disk_name, "%s%d",
236 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
237
238 bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
239 if (bank->disk->queue == NULL) {
240 dev_err(&device->dev, "Cannot register disk queue\n");
241 rc = -EFAULT;
242 goto failed;
243 }
244
245 set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
246 blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
247 blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
248 add_disk(bank->disk);
249
250 bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
251 if (bank->irq_id == NO_IRQ) {
252 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
253 rc = -EFAULT;
254 goto failed;
255 }
256
257 rc = request_irq(bank->irq_id, axon_ram_irq_handler,
258 AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
259 if (rc != 0) {
260 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
261 bank->irq_id = NO_IRQ;
262 rc = -EFAULT;
263 goto failed;
264 }
265
266 rc = device_create_file(&device->dev, &dev_attr_ecc);
267 if (rc != 0) {
268 dev_err(&device->dev, "Cannot create sysfs file\n");
269 rc = -EFAULT;
270 goto failed;
271 }
272
273 azfs_minor += bank->disk->minors;
274
275 return 0;
276
277 failed:
278 if (bank != NULL) {
279 if (bank->irq_id != NO_IRQ)
280 free_irq(bank->irq_id, device);
281 if (bank->disk != NULL) {
282 if (bank->disk->major > 0)
283 unregister_blkdev(bank->disk->major,
284 bank->disk->disk_name);
285 del_gendisk(bank->disk);
286 }
287 device->dev.platform_data = NULL;
288 if (bank->io_addr != 0)
289 iounmap((void __iomem *) bank->io_addr);
290 kfree(bank);
291 }
292
293 return rc;
294 }
295
296 /**
297 * axon_ram_remove - remove() method for platform driver
298 * @device: see of_platform_driver method
299 */
300 static int
axon_ram_remove(struct platform_device * device)301 axon_ram_remove(struct platform_device *device)
302 {
303 struct axon_ram_bank *bank = device->dev.platform_data;
304
305 BUG_ON(!bank || !bank->disk);
306
307 device_remove_file(&device->dev, &dev_attr_ecc);
308 free_irq(bank->irq_id, device);
309 del_gendisk(bank->disk);
310 iounmap((void __iomem *) bank->io_addr);
311 kfree(bank);
312
313 return 0;
314 }
315
316 static struct of_device_id axon_ram_device_id[] = {
317 {
318 .type = "dma-memory"
319 },
320 {}
321 };
322
323 static struct platform_driver axon_ram_driver = {
324 .probe = axon_ram_probe,
325 .remove = axon_ram_remove,
326 .driver = {
327 .name = AXON_RAM_MODULE_NAME,
328 .owner = THIS_MODULE,
329 .of_match_table = axon_ram_device_id,
330 },
331 };
332
333 /**
334 * axon_ram_init
335 */
336 static int __init
axon_ram_init(void)337 axon_ram_init(void)
338 {
339 azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
340 if (azfs_major < 0) {
341 printk(KERN_ERR "%s cannot become block device major number\n",
342 AXON_RAM_MODULE_NAME);
343 return -EFAULT;
344 }
345 azfs_minor = 0;
346
347 return platform_driver_register(&axon_ram_driver);
348 }
349
350 /**
351 * axon_ram_exit
352 */
353 static void __exit
axon_ram_exit(void)354 axon_ram_exit(void)
355 {
356 platform_driver_unregister(&axon_ram_driver);
357 unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
358 }
359
360 module_init(axon_ram_init);
361 module_exit(axon_ram_exit);
362
363 MODULE_LICENSE("GPL");
364 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
365 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
366