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         unsigned short idx;
 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                         return;
 123                 }
 124
 125                 user_mem = page_address(vec->bv_page) + vec->bv_offset;
 126                 if (bio_data_dir(bio) == READ)
 127                         memcpy(user_mem, (void *) phys_mem, vec->bv_len);
 128                 else
 129                         memcpy((void *) phys_mem, user_mem, vec->bv_len);
 130
 131                 phys_mem += vec->bv_len;
 132                 transfered += vec->bv_len;
 133         }
 134         bio_endio(bio, 0);
 135 }
 136
 137 /**
 138  * axon_ram_direct_access - direct_access() method for block device
 139  * @device, @sector, @data: see block_device_operations method
 140  */
 141 static int
 142 axon_ram_direct_access(struct block_device *device, sector_t sector,
 143                        void **kaddr, unsigned long *pfn)
 144 {
 145         struct axon_ram_bank *bank = device->bd_disk->private_data;
 146         loff_t offset;
 147
 148         offset = sector;
 149         if (device->bd_part != NULL)
 150                 offset += device->bd_part->start_sect;
 151         offset <<= 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 const 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: see platform_driver method
 171  */
 172 static int axon_ram_probe(struct platform_device *device)
 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->dev.of_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->dev.of_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_size(&resource);
 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_prot(
 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->major = azfs_major;
 230         bank->disk->first_minor = azfs_minor;
 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
 238         bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
 239         if (bank->disk->queue == NULL) {
 240                 dev_err(&device->dev, "Cannot register disk queue\n");
 241                 rc = -EFAULT;
 242                 goto failed;
 243         }
 244
 245         set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
 246         blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
 247         blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 248         add_disk(bank->disk);
 249
 250         bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
 251         if (bank->irq_id == NO_IRQ) {
 252                 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
 253                 rc = -EFAULT;
 254                 goto failed;
 255         }
 256
 257         rc = request_irq(bank->irq_id, axon_ram_irq_handler,
 258                         AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
 259         if (rc != 0) {
 260                 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
 261                 bank->irq_id = NO_IRQ;
 262                 rc = -EFAULT;
 263                 goto failed;
 264         }
 265
 266         rc = device_create_file(&device->dev, &dev_attr_ecc);
 267         if (rc != 0) {
 268                 dev_err(&device->dev, "Cannot create sysfs file\n");
 269                 rc = -EFAULT;
 270                 goto failed;
 271         }
 272
 273         azfs_minor += bank->disk->minors;
 274
 275         return 0;
 276
 277 failed:
 278         if (bank != NULL) {
 279                 if (bank->irq_id != NO_IRQ)
 280                         free_irq(bank->irq_id, device);
 281                 if (bank->disk != NULL) {
 282                         if (bank->disk->major > 0)
 283                                 unregister_blkdev(bank->disk->major,
 284                                                 bank->disk->disk_name);
 285                         del_gendisk(bank->disk);
 286                 }
 287                 device->dev.platform_data = NULL;
 288                 if (bank->io_addr != 0)
 289                         iounmap((void __iomem *) bank->io_addr);
 290                 kfree(bank);
 291         }
 292
 293         return rc;
 294 }
 295
 296 /**
 297  * axon_ram_remove - remove() method for platform driver
 298  * @device: see of_platform_driver method
 299  */
 300 static int
 301 axon_ram_remove(struct platform_device *device)
 302 {
 303         struct axon_ram_bank *bank = device->dev.platform_data;
 304
 305         BUG_ON(!bank || !bank->disk);
 306
 307         device_remove_file(&device->dev, &dev_attr_ecc);
 308         free_irq(bank->irq_id, device);
 309         del_gendisk(bank->disk);
 310         iounmap((void __iomem *) bank->io_addr);
 311         kfree(bank);
 312
 313         return 0;
 314 }
 315
 316 static struct of_device_id axon_ram_device_id[] = {
 317         {
 318                 .type   = "dma-memory"
 319         },
 320         {}
 321 };
 322
 323 static struct platform_driver axon_ram_driver = {
 324         .probe          = axon_ram_probe,
 325         .remove         = axon_ram_remove,
 326         .driver = {
 327                 .name = AXON_RAM_MODULE_NAME,
 328                 .owner = THIS_MODULE,
 329                 .of_match_table = axon_ram_device_id,
 330         },
 331 };
 332
 333 /**
 334  * axon_ram_init
 335  */
 336 static int __init
 337 axon_ram_init(void)
 338 {
 339         azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 340         if (azfs_major < 0) {
 341                 printk(KERN_ERR "%s cannot become block device major number\n",
 342                                 AXON_RAM_MODULE_NAME);
 343                 return -EFAULT;
 344         }
 345         azfs_minor = 0;
 346
 347         return platform_driver_register(&axon_ram_driver);
 348 }
 349
 350 /**
 351  * axon_ram_exit
 352  */
 353 static void __exit
 354 axon_ram_exit(void)
 355 {
 356         platform_driver_unregister(&axon_ram_driver);
 357         unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 358 }
 359
 360 module_init(axon_ram_init);
 361 module_exit(axon_ram_exit);
 362
 363 MODULE_LICENSE("GPL");
 364 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 365 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");