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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/buffer_head.h>
29#include <linux/device.h>
30#include <linux/errno.h>
31#include <linux/fs.h>
32#include <linux/genhd.h>
33#include <linux/interrupt.h>
34#include <linux/io.h>
35#include <linux/ioport.h>
36#include <linux/irq.h>
37#include <linux/irqreturn.h>
38#include <linux/kernel.h>
39#include <linux/mm.h>
40#include <linux/mod_devicetable.h>
41#include <linux/module.h>
42#include <linux/slab.h>
43#include <linux/string.h>
44#include <linux/types.h>
45#include <linux/of_device.h>
46#include <linux/of_platform.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
60static int azfs_major, azfs_minor;
61
62struct 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
72static ssize_t
73axon_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
83static 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 */
90static irqreturn_t
91axon_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 */
107static int
108axon_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 unsigned short idx;
116 int rc = 0;
117
118 phys_mem = bank->io_addr + (bio->bi_sector << AXON_RAM_SECTOR_SHIFT);
119 phys_end = bank->io_addr + bank->size;
120 transfered = 0;
121 bio_for_each_segment(vec, bio, idx) {
122 if (unlikely(phys_mem + vec->bv_len > phys_end)) {
123 bio_io_error(bio);
124 rc = -ERANGE;
125 break;
126 }
127
128 user_mem = page_address(vec->bv_page) + vec->bv_offset;
129 if (bio_data_dir(bio) == READ)
130 memcpy(user_mem, (void *) phys_mem, vec->bv_len);
131 else
132 memcpy((void *) phys_mem, user_mem, vec->bv_len);
133
134 phys_mem += vec->bv_len;
135 transfered += vec->bv_len;
136 }
137 bio_endio(bio, 0);
138
139 return rc;
140}
141
142/**
143 * axon_ram_direct_access - direct_access() method for block device
144 * @device, @sector, @data: see block_device_operations method
145 */
146static int
147axon_ram_direct_access(struct block_device *device, sector_t sector,
148 void **kaddr, unsigned long *pfn)
149{
150 struct axon_ram_bank *bank = device->bd_disk->private_data;
151 loff_t offset;
152
153 offset = sector;
154 if (device->bd_part != NULL)
155 offset += device->bd_part->start_sect;
156 offset <<= AXON_RAM_SECTOR_SHIFT;
157 if (offset >= bank->size) {
158 dev_err(&bank->device->dev, "Access outside of address space\n");
159 return -ERANGE;
160 }
161
162 *kaddr = (void *)(bank->ph_addr + offset);
163 *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
164
165 return 0;
166}
167
168static const struct block_device_operations axon_ram_devops = {
169 .owner = THIS_MODULE,
170 .direct_access = axon_ram_direct_access
171};
172
173/**
174 * axon_ram_probe - probe() method for platform driver
175 * @device: see platform_driver method
176 */
177static int axon_ram_probe(struct platform_device *device)
178{
179 static int axon_ram_bank_id = -1;
180 struct axon_ram_bank *bank;
181 struct resource resource;
182 int rc = 0;
183
184 axon_ram_bank_id++;
185
186 dev_info(&device->dev, "Found memory controller on %s\n",
187 device->dev.of_node->full_name);
188
189 bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
190 if (bank == NULL) {
191 dev_err(&device->dev, "Out of memory\n");
192 rc = -ENOMEM;
193 goto failed;
194 }
195
196 device->dev.platform_data = bank;
197
198 bank->device = device;
199
200 if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
201 dev_err(&device->dev, "Cannot access device tree\n");
202 rc = -EFAULT;
203 goto failed;
204 }
205
206 bank->size = resource_size(&resource);
207
208 if (bank->size == 0) {
209 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
210 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
211 rc = -ENODEV;
212 goto failed;
213 }
214
215 dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
216 AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
217
218 bank->ph_addr = resource.start;
219 bank->io_addr = (unsigned long) ioremap_prot(
220 bank->ph_addr, bank->size, _PAGE_NO_CACHE);
221 if (bank->io_addr == 0) {
222 dev_err(&device->dev, "ioremap() failed\n");
223 rc = -EFAULT;
224 goto failed;
225 }
226
227 bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
228 if (bank->disk == NULL) {
229 dev_err(&device->dev, "Cannot register disk\n");
230 rc = -EFAULT;
231 goto failed;
232 }
233
234 bank->disk->major = azfs_major;
235 bank->disk->first_minor = azfs_minor;
236 bank->disk->fops = &axon_ram_devops;
237 bank->disk->private_data = bank;
238 bank->disk->driverfs_dev = &device->dev;
239
240 sprintf(bank->disk->disk_name, "%s%d",
241 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
242
243 bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
244 if (bank->disk->queue == NULL) {
245 dev_err(&device->dev, "Cannot register disk queue\n");
246 rc = -EFAULT;
247 goto failed;
248 }
249
250 set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
251 blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
252 blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
253 add_disk(bank->disk);
254
255 bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
256 if (bank->irq_id == NO_IRQ) {
257 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
258 rc = -EFAULT;
259 goto failed;
260 }
261
262 rc = request_irq(bank->irq_id, axon_ram_irq_handler,
263 AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
264 if (rc != 0) {
265 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
266 bank->irq_id = NO_IRQ;
267 rc = -EFAULT;
268 goto failed;
269 }
270
271 rc = device_create_file(&device->dev, &dev_attr_ecc);
272 if (rc != 0) {
273 dev_err(&device->dev, "Cannot create sysfs file\n");
274 rc = -EFAULT;
275 goto failed;
276 }
277
278 azfs_minor += bank->disk->minors;
279
280 return 0;
281
282failed:
283 if (bank != NULL) {
284 if (bank->irq_id != NO_IRQ)
285 free_irq(bank->irq_id, device);
286 if (bank->disk != NULL) {
287 if (bank->disk->major > 0)
288 unregister_blkdev(bank->disk->major,
289 bank->disk->disk_name);
290 del_gendisk(bank->disk);
291 }
292 device->dev.platform_data = NULL;
293 if (bank->io_addr != 0)
294 iounmap((void __iomem *) bank->io_addr);
295 kfree(bank);
296 }
297
298 return rc;
299}
300
301/**
302 * axon_ram_remove - remove() method for platform driver
303 * @device: see of_platform_driver method
304 */
305static int
306axon_ram_remove(struct platform_device *device)
307{
308 struct axon_ram_bank *bank = device->dev.platform_data;
309
310 BUG_ON(!bank || !bank->disk);
311
312 device_remove_file(&device->dev, &dev_attr_ecc);
313 free_irq(bank->irq_id, device);
314 del_gendisk(bank->disk);
315 iounmap((void __iomem *) bank->io_addr);
316 kfree(bank);
317
318 return 0;
319}
320
321static struct of_device_id axon_ram_device_id[] = {
322 {
323 .type = "dma-memory"
324 },
325 {}
326};
327
328static struct platform_driver axon_ram_driver = {
329 .probe = axon_ram_probe,
330 .remove = axon_ram_remove,
331 .driver = {
332 .name = AXON_RAM_MODULE_NAME,
333 .owner = THIS_MODULE,
334 .of_match_table = axon_ram_device_id,
335 },
336};
337
338/**
339 * axon_ram_init
340 */
341static int __init
342axon_ram_init(void)
343{
344 azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
345 if (azfs_major < 0) {
346 printk(KERN_ERR "%s cannot become block device major number\n",
347 AXON_RAM_MODULE_NAME);
348 return -EFAULT;
349 }
350 azfs_minor = 0;
351
352 return platform_driver_register(&axon_ram_driver);
353}
354
355/**
356 * axon_ram_exit
357 */
358static void __exit
359axon_ram_exit(void)
360{
361 platform_driver_unregister(&axon_ram_driver);
362 unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
363}
364
365module_init(axon_ram_init);
366module_exit(axon_ram_exit);
367
368MODULE_LICENSE("GPL");
369MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
370MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");