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 #include <linux/pfn_t.h>
47
48 #include <asm/page.h>
49 #include <asm/prom.h>
50
51 #define AXON_RAM_MODULE_NAME "axonram"
52 #define AXON_RAM_DEVICE_NAME "axonram"
53 #define AXON_RAM_MINORS_PER_DISK 16
54 #define AXON_RAM_BLOCK_SHIFT PAGE_SHIFT
55 #define AXON_RAM_BLOCK_SIZE 1 << AXON_RAM_BLOCK_SHIFT
56 #define AXON_RAM_SECTOR_SHIFT 9
57 #define AXON_RAM_SECTOR_SIZE 1 << AXON_RAM_SECTOR_SHIFT
58 #define AXON_RAM_IRQ_FLAGS IRQF_SHARED | IRQF_TRIGGER_RISING
59
60 static int azfs_major, azfs_minor;
61
62 struct axon_ram_bank {
63 struct platform_device *device;
64 struct gendisk *disk;
65 unsigned int irq_id;
66 unsigned long ph_addr;
67 unsigned long io_addr;
68 unsigned long size;
69 unsigned long ecc_counter;
70 };
71
72 static ssize_t
axon_ram_sysfs_ecc(struct device * dev,struct device_attribute * attr,char * buf)73 axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
74 {
75 struct platform_device *device = to_platform_device(dev);
76 struct axon_ram_bank *bank = device->dev.platform_data;
77
78 BUG_ON(!bank);
79
80 return sprintf(buf, "%ld\n", bank->ecc_counter);
81 }
82
83 static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
84
85 /**
86 * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
87 * @irq: interrupt ID
88 * @dev: pointer to of_device
89 */
90 static irqreturn_t
axon_ram_irq_handler(int irq,void * dev)91 axon_ram_irq_handler(int irq, void *dev)
92 {
93 struct platform_device *device = dev;
94 struct axon_ram_bank *bank = device->dev.platform_data;
95
96 BUG_ON(!bank);
97
98 dev_err(&device->dev, "Correctable memory error occurred\n");
99 bank->ecc_counter++;
100 return IRQ_HANDLED;
101 }
102
103 /**
104 * axon_ram_make_request - make_request() method for block device
105 * @queue, @bio: see blk_queue_make_request()
106 */
107 static blk_qc_t
axon_ram_make_request(struct request_queue * queue,struct bio * bio)108 axon_ram_make_request(struct request_queue *queue, struct bio *bio)
109 {
110 struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
111 unsigned long phys_mem, phys_end;
112 void *user_mem;
113 struct bio_vec vec;
114 unsigned int transfered;
115 struct bvec_iter iter;
116
117 phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
118 AXON_RAM_SECTOR_SHIFT);
119 phys_end = bank->io_addr + bank->size;
120 transfered = 0;
121 bio_for_each_segment(vec, bio, iter) {
122 if (unlikely(phys_mem + vec.bv_len > phys_end)) {
123 bio_io_error(bio);
124 return BLK_QC_T_NONE;
125 }
126
127 user_mem = page_address(vec.bv_page) + vec.bv_offset;
128 if (bio_data_dir(bio) == READ)
129 memcpy(user_mem, (void *) phys_mem, vec.bv_len);
130 else
131 memcpy((void *) phys_mem, user_mem, vec.bv_len);
132
133 phys_mem += vec.bv_len;
134 transfered += vec.bv_len;
135 }
136 bio_endio(bio);
137 return BLK_QC_T_NONE;
138 }
139
140 /**
141 * axon_ram_direct_access - direct_access() method for block device
142 * @device, @sector, @data: see block_device_operations method
143 */
144 static long
axon_ram_direct_access(struct block_device * device,sector_t sector,void ** kaddr,pfn_t * pfn,long size)145 axon_ram_direct_access(struct block_device *device, sector_t sector,
146 void **kaddr, pfn_t *pfn, long size)
147 {
148 struct axon_ram_bank *bank = device->bd_disk->private_data;
149 loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
150
151 *kaddr = (void *) bank->io_addr + offset;
152 *pfn = phys_to_pfn_t(bank->ph_addr + offset, PFN_DEV);
153 return bank->size - offset;
154 }
155
156 static const struct block_device_operations axon_ram_devops = {
157 .owner = THIS_MODULE,
158 .direct_access = axon_ram_direct_access
159 };
160
161 /**
162 * axon_ram_probe - probe() method for platform driver
163 * @device: see platform_driver method
164 */
axon_ram_probe(struct platform_device * device)165 static int axon_ram_probe(struct platform_device *device)
166 {
167 static int axon_ram_bank_id = -1;
168 struct axon_ram_bank *bank;
169 struct resource resource;
170 int rc = 0;
171
172 axon_ram_bank_id++;
173
174 dev_info(&device->dev, "Found memory controller on %s\n",
175 device->dev.of_node->full_name);
176
177 bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
178 if (bank == NULL) {
179 dev_err(&device->dev, "Out of memory\n");
180 rc = -ENOMEM;
181 goto failed;
182 }
183
184 device->dev.platform_data = bank;
185
186 bank->device = device;
187
188 if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
189 dev_err(&device->dev, "Cannot access device tree\n");
190 rc = -EFAULT;
191 goto failed;
192 }
193
194 bank->size = resource_size(&resource);
195
196 if (bank->size == 0) {
197 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
198 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
199 rc = -ENODEV;
200 goto failed;
201 }
202
203 dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
204 AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
205
206 bank->ph_addr = resource.start;
207 bank->io_addr = (unsigned long) ioremap_prot(
208 bank->ph_addr, bank->size, _PAGE_NO_CACHE);
209 if (bank->io_addr == 0) {
210 dev_err(&device->dev, "ioremap() failed\n");
211 rc = -EFAULT;
212 goto failed;
213 }
214
215 bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
216 if (bank->disk == NULL) {
217 dev_err(&device->dev, "Cannot register disk\n");
218 rc = -EFAULT;
219 goto failed;
220 }
221
222 bank->disk->major = azfs_major;
223 bank->disk->first_minor = azfs_minor;
224 bank->disk->fops = &axon_ram_devops;
225 bank->disk->private_data = bank;
226
227 sprintf(bank->disk->disk_name, "%s%d",
228 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
229
230 bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
231 if (bank->disk->queue == NULL) {
232 dev_err(&device->dev, "Cannot register disk queue\n");
233 rc = -EFAULT;
234 goto failed;
235 }
236
237 set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
238 blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
239 blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
240 device_add_disk(&device->dev, bank->disk);
241
242 bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
243 if (!bank->irq_id) {
244 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
245 rc = -EFAULT;
246 goto failed;
247 }
248
249 rc = request_irq(bank->irq_id, axon_ram_irq_handler,
250 AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
251 if (rc != 0) {
252 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
253 bank->irq_id = 0;
254 rc = -EFAULT;
255 goto failed;
256 }
257
258 rc = device_create_file(&device->dev, &dev_attr_ecc);
259 if (rc != 0) {
260 dev_err(&device->dev, "Cannot create sysfs file\n");
261 rc = -EFAULT;
262 goto failed;
263 }
264
265 azfs_minor += bank->disk->minors;
266
267 return 0;
268
269 failed:
270 if (bank != NULL) {
271 if (bank->irq_id)
272 free_irq(bank->irq_id, device);
273 if (bank->disk != NULL) {
274 if (bank->disk->major > 0)
275 unregister_blkdev(bank->disk->major,
276 bank->disk->disk_name);
277 if (bank->disk->flags & GENHD_FL_UP)
278 del_gendisk(bank->disk);
279 put_disk(bank->disk);
280 }
281 device->dev.platform_data = NULL;
282 if (bank->io_addr != 0)
283 iounmap((void __iomem *) bank->io_addr);
284 kfree(bank);
285 }
286
287 return rc;
288 }
289
290 /**
291 * axon_ram_remove - remove() method for platform driver
292 * @device: see of_platform_driver method
293 */
294 static int
axon_ram_remove(struct platform_device * device)295 axon_ram_remove(struct platform_device *device)
296 {
297 struct axon_ram_bank *bank = device->dev.platform_data;
298
299 BUG_ON(!bank || !bank->disk);
300
301 device_remove_file(&device->dev, &dev_attr_ecc);
302 free_irq(bank->irq_id, device);
303 del_gendisk(bank->disk);
304 put_disk(bank->disk);
305 iounmap((void __iomem *) bank->io_addr);
306 kfree(bank);
307
308 return 0;
309 }
310
311 static const struct of_device_id axon_ram_device_id[] = {
312 {
313 .type = "dma-memory"
314 },
315 {}
316 };
317 MODULE_DEVICE_TABLE(of, axon_ram_device_id);
318
319 static struct platform_driver axon_ram_driver = {
320 .probe = axon_ram_probe,
321 .remove = axon_ram_remove,
322 .driver = {
323 .name = AXON_RAM_MODULE_NAME,
324 .of_match_table = axon_ram_device_id,
325 },
326 };
327
328 /**
329 * axon_ram_init
330 */
331 static int __init
axon_ram_init(void)332 axon_ram_init(void)
333 {
334 azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
335 if (azfs_major < 0) {
336 printk(KERN_ERR "%s cannot become block device major number\n",
337 AXON_RAM_MODULE_NAME);
338 return -EFAULT;
339 }
340 azfs_minor = 0;
341
342 return platform_driver_register(&axon_ram_driver);
343 }
344
345 /**
346 * axon_ram_exit
347 */
348 static void __exit
axon_ram_exit(void)349 axon_ram_exit(void)
350 {
351 platform_driver_unregister(&axon_ram_driver);
352 unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
353 }
354
355 module_init(axon_ram_init);
356 module_exit(axon_ram_exit);
357
358 MODULE_LICENSE("GPL");
359 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
360 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
361