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 blk_qc_t
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 struct bvec_iter iter;
115
116 phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
117 AXON_RAM_SECTOR_SHIFT);
118 phys_end = bank->io_addr + bank->size;
119 transfered = 0;
120 bio_for_each_segment(vec, bio, iter) {
121 if (unlikely(phys_mem + vec.bv_len > phys_end)) {
122 bio_io_error(bio);
123 return BLK_QC_T_NONE;
124 }
125
126 user_mem = page_address(vec.bv_page) + vec.bv_offset;
127 if (bio_data_dir(bio) == READ)
128 memcpy(user_mem, (void *) phys_mem, vec.bv_len);
129 else
130 memcpy((void *) phys_mem, user_mem, vec.bv_len);
131
132 phys_mem += vec.bv_len;
133 transfered += vec.bv_len;
134 }
135 bio_endio(bio);
136 return BLK_QC_T_NONE;
137 }
138
139 /**
140 * axon_ram_direct_access - direct_access() method for block device
141 * @device, @sector, @data: see block_device_operations method
142 */
143 static long
axon_ram_direct_access(struct block_device * device,sector_t sector,void __pmem ** kaddr,unsigned long * pfn)144 axon_ram_direct_access(struct block_device *device, sector_t sector,
145 void __pmem **kaddr, unsigned long *pfn)
146 {
147 struct axon_ram_bank *bank = device->bd_disk->private_data;
148 loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
149 void *addr = (void *)(bank->ph_addr + offset);
150
151 *kaddr = (void __pmem *)addr;
152 *pfn = virt_to_phys(addr) >> PAGE_SHIFT;
153
154 return bank->size - offset;
155 }
156
157 static const struct block_device_operations axon_ram_devops = {
158 .owner = THIS_MODULE,
159 .direct_access = axon_ram_direct_access
160 };
161
162 /**
163 * axon_ram_probe - probe() method for platform driver
164 * @device: see platform_driver method
165 */
axon_ram_probe(struct platform_device * device)166 static int axon_ram_probe(struct platform_device *device)
167 {
168 static int axon_ram_bank_id = -1;
169 struct axon_ram_bank *bank;
170 struct resource resource;
171 int rc = 0;
172
173 axon_ram_bank_id++;
174
175 dev_info(&device->dev, "Found memory controller on %s\n",
176 device->dev.of_node->full_name);
177
178 bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
179 if (bank == NULL) {
180 dev_err(&device->dev, "Out of memory\n");
181 rc = -ENOMEM;
182 goto failed;
183 }
184
185 device->dev.platform_data = bank;
186
187 bank->device = device;
188
189 if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
190 dev_err(&device->dev, "Cannot access device tree\n");
191 rc = -EFAULT;
192 goto failed;
193 }
194
195 bank->size = resource_size(&resource);
196
197 if (bank->size == 0) {
198 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
199 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
200 rc = -ENODEV;
201 goto failed;
202 }
203
204 dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
205 AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
206
207 bank->ph_addr = resource.start;
208 bank->io_addr = (unsigned long) ioremap_prot(
209 bank->ph_addr, bank->size, _PAGE_NO_CACHE);
210 if (bank->io_addr == 0) {
211 dev_err(&device->dev, "ioremap() failed\n");
212 rc = -EFAULT;
213 goto failed;
214 }
215
216 bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
217 if (bank->disk == NULL) {
218 dev_err(&device->dev, "Cannot register disk\n");
219 rc = -EFAULT;
220 goto failed;
221 }
222
223 bank->disk->major = azfs_major;
224 bank->disk->first_minor = azfs_minor;
225 bank->disk->fops = &axon_ram_devops;
226 bank->disk->private_data = bank;
227 bank->disk->driverfs_dev = &device->dev;
228
229 sprintf(bank->disk->disk_name, "%s%d",
230 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
231
232 bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
233 if (bank->disk->queue == NULL) {
234 dev_err(&device->dev, "Cannot register disk queue\n");
235 rc = -EFAULT;
236 goto failed;
237 }
238
239 set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
240 blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
241 blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
242 add_disk(bank->disk);
243
244 bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
245 if (bank->irq_id == NO_IRQ) {
246 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
247 rc = -EFAULT;
248 goto failed;
249 }
250
251 rc = request_irq(bank->irq_id, axon_ram_irq_handler,
252 AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
253 if (rc != 0) {
254 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
255 bank->irq_id = NO_IRQ;
256 rc = -EFAULT;
257 goto failed;
258 }
259
260 rc = device_create_file(&device->dev, &dev_attr_ecc);
261 if (rc != 0) {
262 dev_err(&device->dev, "Cannot create sysfs file\n");
263 rc = -EFAULT;
264 goto failed;
265 }
266
267 azfs_minor += bank->disk->minors;
268
269 return 0;
270
271 failed:
272 if (bank != NULL) {
273 if (bank->irq_id != NO_IRQ)
274 free_irq(bank->irq_id, device);
275 if (bank->disk != NULL) {
276 if (bank->disk->major > 0)
277 unregister_blkdev(bank->disk->major,
278 bank->disk->disk_name);
279 del_gendisk(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 iounmap((void __iomem *) bank->io_addr);
305 kfree(bank);
306
307 return 0;
308 }
309
310 static const struct of_device_id axon_ram_device_id[] = {
311 {
312 .type = "dma-memory"
313 },
314 {}
315 };
316
317 static struct platform_driver axon_ram_driver = {
318 .probe = axon_ram_probe,
319 .remove = axon_ram_remove,
320 .driver = {
321 .name = AXON_RAM_MODULE_NAME,
322 .of_match_table = axon_ram_device_id,
323 },
324 };
325
326 /**
327 * axon_ram_init
328 */
329 static int __init
axon_ram_init(void)330 axon_ram_init(void)
331 {
332 azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
333 if (azfs_major < 0) {
334 printk(KERN_ERR "%s cannot become block device major number\n",
335 AXON_RAM_MODULE_NAME);
336 return -EFAULT;
337 }
338 azfs_minor = 0;
339
340 return platform_driver_register(&axon_ram_driver);
341 }
342
343 /**
344 * axon_ram_exit
345 */
346 static void __exit
axon_ram_exit(void)347 axon_ram_exit(void)
348 {
349 platform_driver_unregister(&axon_ram_driver);
350 unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
351 }
352
353 module_init(axon_ram_init);
354 module_exit(axon_ram_exit);
355
356 MODULE_LICENSE("GPL");
357 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
358 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
359