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");