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/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
  60 struct axon_ram_bank {
  61         struct of_device        *device;
  62         struct gendisk          *disk;
  63         unsigned int            irq_id;
  64         unsigned long           ph_addr;
  65         unsigned long           io_addr;
  66         unsigned long           size;
  67         unsigned long           ecc_counter;
  68 };
  69
  70 static ssize_t
  71 axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
  72 {
  73         struct of_device *device = to_of_device(dev);
  74         struct axon_ram_bank *bank = device->dev.platform_data;
  75
  76         BUG_ON(!bank);
  77
  78         return sprintf(buf, "%ld\n", bank->ecc_counter);
  79 }
  80
  81 static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
  82
  83 /**
  84  * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
  85  * @irq: interrupt ID
  86  * @dev: pointer to of_device
  87  */
  88 static irqreturn_t
  89 axon_ram_irq_handler(int irq, void *dev)
  90 {
  91         struct of_device *device = dev;
  92         struct axon_ram_bank *bank = device->dev.platform_data;
  93
  94         BUG_ON(!bank);
  95
  96         dev_err(&device->dev, "Correctable memory error occured\n");
  97         bank->ecc_counter++;
  98         return IRQ_HANDLED;
  99 }
 100
 101 /**
 102  * axon_ram_make_request - make_request() method for block device
 103  * @queue, @bio: see blk_queue_make_request()
 104  */
 105 static int
 106 axon_ram_make_request(struct request_queue *queue, struct bio *bio)
 107 {
 108         struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
 109         unsigned long phys_mem, phys_end;
 110         void *user_mem;
 111         struct bio_vec *vec;
 112         unsigned int transfered;
 113         unsigned short idx;
 114         int rc = 0;
 115
 116         phys_mem = bank->io_addr + (bio->bi_sector << AXON_RAM_SECTOR_SHIFT);
 117         phys_end = bank->io_addr + bank->size;
 118         transfered = 0;
 119         bio_for_each_segment(vec, bio, idx) {
 120                 if (unlikely(phys_mem + vec->bv_len > phys_end)) {
 121                         bio_io_error(bio);
 122                         rc = -ERANGE;
 123                         break;
 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         return rc;
 138 }
 139
 140 /**
 141  * axon_ram_direct_access - direct_access() method for block device
 142  * @device, @sector, @data: see block_device_operations method
 143  */
 144 static int
 145 axon_ram_direct_access(struct block_device *device, sector_t sector,
 146                        unsigned long *data)
 147 {
 148         struct axon_ram_bank *bank = device->bd_disk->private_data;
 149         loff_t offset;
 150
 151         offset = sector << AXON_RAM_SECTOR_SHIFT;
 152         if (offset >= bank->size) {
 153                 dev_err(&bank->device->dev, "Access outside of address space\n");
 154                 return -ERANGE;
 155         }
 156
 157         *data = bank->ph_addr + offset;
 158
 159         return 0;
 160 }
 161
 162 static struct block_device_operations axon_ram_devops = {
 163         .owner          = THIS_MODULE,
 164         .direct_access  = axon_ram_direct_access
 165 };
 166
 167 /**
 168  * axon_ram_probe - probe() method for platform driver
 169  * @device, @device_id: see of_platform_driver method
 170  */
 171 static int
 172 axon_ram_probe(struct of_device *device, const struct of_device_id *device_id)
 173 {
 174         static int axon_ram_bank_id = -1;
 175         struct axon_ram_bank *bank;
 176         struct resource resource;
 177         int rc = 0;
 178
 179         axon_ram_bank_id++;
 180
 181         dev_info(&device->dev, "Found memory controller on %s\n",
 182                         device->node->full_name);
 183
 184         bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
 185         if (bank == NULL) {
 186                 dev_err(&device->dev, "Out of memory\n");
 187                 rc = -ENOMEM;
 188                 goto failed;
 189         }
 190
 191         device->dev.platform_data = bank;
 192
 193         bank->device = device;
 194
 195         if (of_address_to_resource(device->node, 0, &resource) != 0) {
 196                 dev_err(&device->dev, "Cannot access device tree\n");
 197                 rc = -EFAULT;
 198                 goto failed;
 199         }
 200
 201         bank->size = resource.end - resource.start + 1;
 202
 203         if (bank->size == 0) {
 204                 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
 205                                 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 206                 rc = -ENODEV;
 207                 goto failed;
 208         }
 209
 210         dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
 211                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
 212
 213         bank->ph_addr = resource.start;
 214         bank->io_addr = (unsigned long) ioremap_flags(
 215                         bank->ph_addr, bank->size, _PAGE_NO_CACHE);
 216         if (bank->io_addr == 0) {
 217                 dev_err(&device->dev, "ioremap() failed\n");
 218                 rc = -EFAULT;
 219                 goto failed;
 220         }
 221
 222         bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
 223         if (bank->disk == NULL) {
 224                 dev_err(&device->dev, "Cannot register disk\n");
 225                 rc = -EFAULT;
 226                 goto failed;
 227         }
 228
 229         bank->disk->first_minor = 0;
 230         bank->disk->fops = &axon_ram_devops;
 231         bank->disk->private_data = bank;
 232         bank->disk->driverfs_dev = &device->dev;
 233
 234         sprintf(bank->disk->disk_name, "%s%d",
 235                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 236         bank->disk->major = register_blkdev(0, bank->disk->disk_name);
 237         if (bank->disk->major < 0) {
 238                 dev_err(&device->dev, "Cannot register block device\n");
 239                 rc = -EFAULT;
 240                 goto failed;
 241         }
 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_hardsect_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 253         add_disk(bank->disk);
 254
 255         bank->irq_id = irq_of_parse_and_map(device->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         return 0;
 279
 280 failed:
 281         if (bank != NULL) {
 282                 if (bank->irq_id != NO_IRQ)
 283                         free_irq(bank->irq_id, device);
 284                 if (bank->disk != NULL) {
 285                         if (bank->disk->major > 0)
 286                                 unregister_blkdev(bank->disk->major,
 287                                                 bank->disk->disk_name);
 288                         del_gendisk(bank->disk);
 289                 }
 290                 device->dev.platform_data = NULL;
 291                 if (bank->io_addr != 0)
 292                         iounmap((void __iomem *) bank->io_addr);
 293                 kfree(bank);
 294         }
 295
 296         return rc;
 297 }
 298
 299 /**
 300  * axon_ram_remove - remove() method for platform driver
 301  * @device: see of_platform_driver method
 302  */
 303 static int
 304 axon_ram_remove(struct of_device *device)
 305 {
 306         struct axon_ram_bank *bank = device->dev.platform_data;
 307
 308         BUG_ON(!bank || !bank->disk);
 309
 310         device_remove_file(&device->dev, &dev_attr_ecc);
 311         free_irq(bank->irq_id, device);
 312         unregister_blkdev(bank->disk->major, bank->disk->disk_name);
 313         del_gendisk(bank->disk);
 314         iounmap((void __iomem *) bank->io_addr);
 315         kfree(bank);
 316
 317         return 0;
 318 }
 319
 320 static struct of_device_id axon_ram_device_id[] = {
 321         {
 322                 .type   = "dma-memory"
 323         },
 324         {}
 325 };
 326
 327 static struct of_platform_driver axon_ram_driver = {
 328         .match_table    = axon_ram_device_id,
 329         .probe          = axon_ram_probe,
 330         .remove         = axon_ram_remove,
 331         .driver         = {
 332                 .owner  = THIS_MODULE,
 333                 .name   = AXON_RAM_MODULE_NAME,
 334         },
 335 };
 336
 337 /**
 338  * axon_ram_init
 339  */
 340 static int __init
 341 axon_ram_init(void)
 342 {
 343         return of_register_platform_driver(&axon_ram_driver);
 344 }
 345
 346 /**
 347  * axon_ram_exit
 348  */
 349 static void __exit
 350 axon_ram_exit(void)
 351 {
 352         of_unregister_platform_driver(&axon_ram_driver);
 353 }
 354
 355 module_init(axon_ram_init);
 356 module_exit(axon_ram_exit);
 357
 358 MODULE_LICENSE("GPL");
 359 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 360 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");