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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 long
143 axon_ram_direct_access(struct block_device *device, sector_t sector,
144                        void **kaddr, unsigned long *pfn, long size)
145 {
146         struct axon_ram_bank *bank = device->bd_disk->private_data;
147         loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
148 
149         *kaddr = (void *)(bank->ph_addr + offset);
150         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
151 
152         return bank->size - offset;
153 }
154 
155 static const struct block_device_operations axon_ram_devops = {
156         .owner          = THIS_MODULE,
157         .direct_access  = axon_ram_direct_access
158 };
159 
160 /**
161  * axon_ram_probe - probe() method for platform driver
162  * @device: see platform_driver method
163  */
164 static int axon_ram_probe(struct platform_device *device)
165 {
166         static int axon_ram_bank_id = -1;
167         struct axon_ram_bank *bank;
168         struct resource resource;
169         int rc = 0;
170 
171         axon_ram_bank_id++;
172 
173         dev_info(&device->dev, "Found memory controller on %s\n",
174                         device->dev.of_node->full_name);
175 
176         bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
177         if (bank == NULL) {
178                 dev_err(&device->dev, "Out of memory\n");
179                 rc = -ENOMEM;
180                 goto failed;
181         }
182 
183         device->dev.platform_data = bank;
184 
185         bank->device = device;
186 
187         if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
188                 dev_err(&device->dev, "Cannot access device tree\n");
189                 rc = -EFAULT;
190                 goto failed;
191         }
192 
193         bank->size = resource_size(&resource);
194 
195         if (bank->size == 0) {
196                 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
197                                 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
198                 rc = -ENODEV;
199                 goto failed;
200         }
201 
202         dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
203                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
204 
205         bank->ph_addr = resource.start;
206         bank->io_addr = (unsigned long) ioremap_prot(
207                         bank->ph_addr, bank->size, _PAGE_NO_CACHE);
208         if (bank->io_addr == 0) {
209                 dev_err(&device->dev, "ioremap() failed\n");
210                 rc = -EFAULT;
211                 goto failed;
212         }
213 
214         bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
215         if (bank->disk == NULL) {
216                 dev_err(&device->dev, "Cannot register disk\n");
217                 rc = -EFAULT;
218                 goto failed;
219         }
220 
221         bank->disk->major = azfs_major;
222         bank->disk->first_minor = azfs_minor;
223         bank->disk->fops = &axon_ram_devops;
224         bank->disk->private_data = bank;
225         bank->disk->driverfs_dev = &device->dev;
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         add_disk(bank->disk);
241 
242         bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
243         if (bank->irq_id == NO_IRQ) {
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 = NO_IRQ;
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 != NO_IRQ)
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                         del_gendisk(bank->disk);
278                 }
279                 device->dev.platform_data = NULL;
280                 if (bank->io_addr != 0)
281                         iounmap((void __iomem *) bank->io_addr);
282                 kfree(bank);
283         }
284 
285         return rc;
286 }
287 
288 /**
289  * axon_ram_remove - remove() method for platform driver
290  * @device: see of_platform_driver method
291  */
292 static int
293 axon_ram_remove(struct platform_device *device)
294 {
295         struct axon_ram_bank *bank = device->dev.platform_data;
296 
297         BUG_ON(!bank || !bank->disk);
298 
299         device_remove_file(&device->dev, &dev_attr_ecc);
300         free_irq(bank->irq_id, device);
301         del_gendisk(bank->disk);
302         iounmap((void __iomem *) bank->io_addr);
303         kfree(bank);
304 
305         return 0;
306 }
307 
308 static const struct of_device_id axon_ram_device_id[] = {
309         {
310                 .type   = "dma-memory"
311         },
312         {}
313 };
314 
315 static struct platform_driver axon_ram_driver = {
316         .probe          = axon_ram_probe,
317         .remove         = axon_ram_remove,
318         .driver = {
319                 .name = AXON_RAM_MODULE_NAME,
320                 .of_match_table = axon_ram_device_id,
321         },
322 };
323 
324 /**
325  * axon_ram_init
326  */
327 static int __init
328 axon_ram_init(void)
329 {
330         azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
331         if (azfs_major < 0) {
332                 printk(KERN_ERR "%s cannot become block device major number\n",
333                                 AXON_RAM_MODULE_NAME);
334                 return -EFAULT;
335         }
336         azfs_minor = 0;
337 
338         return platform_driver_register(&axon_ram_driver);
339 }
340 
341 /**
342  * axon_ram_exit
343  */
344 static void __exit
345 axon_ram_exit(void)
346 {
347         platform_driver_unregister(&axon_ram_driver);
348         unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
349 }
350 
351 module_init(axon_ram_init);
352 module_exit(axon_ram_exit);
353 
354 MODULE_LICENSE("GPL");
355 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
356 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
357 

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