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Linux/arch/powerpc/sysdev/axonram.c

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

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