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                        void **kaddr, unsigned long *pfn)
 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         *kaddr = (void *)(bank->ph_addr + offset);
 158         *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
 159
 160         return 0;
 161 }
 162
 163 static struct block_device_operations axon_ram_devops = {
 164         .owner          = THIS_MODULE,
 165         .direct_access  = axon_ram_direct_access
 166 };
 167
 168 /**
 169  * axon_ram_probe - probe() method for platform driver
 170  * @device, @device_id: see of_platform_driver method
 171  */
 172 static int
 173 axon_ram_probe(struct of_device *device, const struct of_device_id *device_id)
 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->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->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.end - resource.start + 1;
 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_flags(
 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->first_minor = 0;
 231         bank->disk->fops = &axon_ram_devops;
 232         bank->disk->private_data = bank;
 233         bank->disk->driverfs_dev = &device->dev;
 234
 235         sprintf(bank->disk->disk_name, "%s%d",
 236                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 237         bank->disk->major = register_blkdev(0, bank->disk->disk_name);
 238         if (bank->disk->major < 0) {
 239                 dev_err(&device->dev, "Cannot register block device\n");
 240                 rc = -EFAULT;
 241                 goto failed;
 242         }
 243
 244         bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
 245         if (bank->disk->queue == NULL) {
 246                 dev_err(&device->dev, "Cannot register disk queue\n");
 247                 rc = -EFAULT;
 248                 goto failed;
 249         }
 250
 251         set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
 252         blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
 253         blk_queue_hardsect_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 254         add_disk(bank->disk);
 255
 256         bank->irq_id = irq_of_parse_and_map(device->node, 0);
 257         if (bank->irq_id == NO_IRQ) {
 258                 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
 259                 rc = -EFAULT;
 260                 goto failed;
 261         }
 262
 263         rc = request_irq(bank->irq_id, axon_ram_irq_handler,
 264                         AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
 265         if (rc != 0) {
 266                 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
 267                 bank->irq_id = NO_IRQ;
 268                 rc = -EFAULT;
 269                 goto failed;
 270         }
 271
 272         rc = device_create_file(&device->dev, &dev_attr_ecc);
 273         if (rc != 0) {
 274                 dev_err(&device->dev, "Cannot create sysfs file\n");
 275                 rc = -EFAULT;
 276                 goto failed;
 277         }
 278
 279         return 0;
 280
 281 failed:
 282         if (bank != NULL) {
 283                 if (bank->irq_id != NO_IRQ)
 284                         free_irq(bank->irq_id, device);
 285                 if (bank->disk != NULL) {
 286                         if (bank->disk->major > 0)
 287                                 unregister_blkdev(bank->disk->major,
 288                                                 bank->disk->disk_name);
 289                         del_gendisk(bank->disk);
 290                 }
 291                 device->dev.platform_data = NULL;
 292                 if (bank->io_addr != 0)
 293                         iounmap((void __iomem *) bank->io_addr);
 294                 kfree(bank);
 295         }
 296
 297         return rc;
 298 }
 299
 300 /**
 301  * axon_ram_remove - remove() method for platform driver
 302  * @device: see of_platform_driver method
 303  */
 304 static int
 305 axon_ram_remove(struct of_device *device)
 306 {
 307         struct axon_ram_bank *bank = device->dev.platform_data;
 308
 309         BUG_ON(!bank || !bank->disk);
 310
 311         device_remove_file(&device->dev, &dev_attr_ecc);
 312         free_irq(bank->irq_id, device);
 313         unregister_blkdev(bank->disk->major, bank->disk->disk_name);
 314         del_gendisk(bank->disk);
 315         iounmap((void __iomem *) bank->io_addr);
 316         kfree(bank);
 317
 318         return 0;
 319 }
 320
 321 static struct of_device_id axon_ram_device_id[] = {
 322         {
 323                 .type   = "dma-memory"
 324         },
 325         {}
 326 };
 327
 328 static struct of_platform_driver axon_ram_driver = {
 329         .match_table    = axon_ram_device_id,
 330         .probe          = axon_ram_probe,
 331         .remove         = axon_ram_remove,
 332         .driver         = {
 333                 .owner  = THIS_MODULE,
 334                 .name   = AXON_RAM_MODULE_NAME,
 335         },
 336 };
 337
 338 /**
 339  * axon_ram_init
 340  */
 341 static int __init
 342 axon_ram_init(void)
 343 {
 344         return of_register_platform_driver(&axon_ram_driver);
 345 }
 346
 347 /**
 348  * axon_ram_exit
 349  */
 350 static void __exit
 351 axon_ram_exit(void)
 352 {
 353         of_unregister_platform_driver(&axon_ram_driver);
 354 }
 355
 356 module_init(axon_ram_init);
 357 module_exit(axon_ram_exit);
 358
 359 MODULE_LICENSE("GPL");
 360 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 361 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");