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 static int azfs_major, azfs_minor;
  61
  62 struct axon_ram_bank {
  63         struct platform_device  *device;
  64         struct gendisk          *disk;
  65         unsigned int            irq_id;
  66         unsigned long           ph_addr;
  67         unsigned long           io_addr;
  68         unsigned long           size;
  69         unsigned long           ecc_counter;
  70 };
  71
  72 static ssize_t
  73 axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
  74 {
  75         struct platform_device *device = to_platform_device(dev);
  76         struct axon_ram_bank *bank = device->dev.platform_data;
  77
  78         BUG_ON(!bank);
  79
  80         return sprintf(buf, "%ld\n", bank->ecc_counter);
  81 }
  82
  83 static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
  84
  85 /**
  86  * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
  87  * @irq: interrupt ID
  88  * @dev: pointer to of_device
  89  */
  90 static irqreturn_t
  91 axon_ram_irq_handler(int irq, void *dev)
  92 {
  93         struct platform_device *device = dev;
  94         struct axon_ram_bank *bank = device->dev.platform_data;
  95
  96         BUG_ON(!bank);
  97
  98         dev_err(&device->dev, "Correctable memory error occured\n");
  99         bank->ecc_counter++;
 100         return IRQ_HANDLED;
 101 }
 102
 103 /**
 104  * axon_ram_make_request - make_request() method for block device
 105  * @queue, @bio: see blk_queue_make_request()
 106  */
 107 static int
 108 axon_ram_make_request(struct request_queue *queue, struct bio *bio)
 109 {
 110         struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
 111         unsigned long phys_mem, phys_end;
 112         void *user_mem;
 113         struct bio_vec *vec;
 114         unsigned int transfered;
 115         unsigned short idx;
 116         int rc = 0;
 117
 118         phys_mem = bank->io_addr + (bio->bi_sector << AXON_RAM_SECTOR_SHIFT);
 119         phys_end = bank->io_addr + bank->size;
 120         transfered = 0;
 121         bio_for_each_segment(vec, bio, idx) {
 122                 if (unlikely(phys_mem + vec->bv_len > phys_end)) {
 123                         bio_io_error(bio);
 124                         rc = -ERANGE;
 125                         break;
 126                 }
 127
 128                 user_mem = page_address(vec->bv_page) + vec->bv_offset;
 129                 if (bio_data_dir(bio) == READ)
 130                         memcpy(user_mem, (void *) phys_mem, vec->bv_len);
 131                 else
 132                         memcpy((void *) phys_mem, user_mem, vec->bv_len);
 133
 134                 phys_mem += vec->bv_len;
 135                 transfered += vec->bv_len;
 136         }
 137         bio_endio(bio, 0);
 138
 139         return rc;
 140 }
 141
 142 /**
 143  * axon_ram_direct_access - direct_access() method for block device
 144  * @device, @sector, @data: see block_device_operations method
 145  */
 146 static int
 147 axon_ram_direct_access(struct block_device *device, sector_t sector,
 148                        void **kaddr, unsigned long *pfn)
 149 {
 150         struct axon_ram_bank *bank = device->bd_disk->private_data;
 151         loff_t offset;
 152
 153         offset = sector;
 154         if (device->bd_part != NULL)
 155                 offset += device->bd_part->start_sect;
 156         offset <<= AXON_RAM_SECTOR_SHIFT;
 157         if (offset >= bank->size) {
 158                 dev_err(&bank->device->dev, "Access outside of address space\n");
 159                 return -ERANGE;
 160         }
 161
 162         *kaddr = (void *)(bank->ph_addr + offset);
 163         *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
 164
 165         return 0;
 166 }
 167
 168 static const struct block_device_operations axon_ram_devops = {
 169         .owner          = THIS_MODULE,
 170         .direct_access  = axon_ram_direct_access
 171 };
 172
 173 /**
 174  * axon_ram_probe - probe() method for platform driver
 175  * @device, @device_id: see of_platform_driver method
 176  */
 177 static int axon_ram_probe(struct platform_device *device,
 178                           const struct of_device_id *device_id)
 179 {
 180         static int axon_ram_bank_id = -1;
 181         struct axon_ram_bank *bank;
 182         struct resource resource;
 183         int rc = 0;
 184
 185         axon_ram_bank_id++;
 186
 187         dev_info(&device->dev, "Found memory controller on %s\n",
 188                         device->dev.of_node->full_name);
 189
 190         bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
 191         if (bank == NULL) {
 192                 dev_err(&device->dev, "Out of memory\n");
 193                 rc = -ENOMEM;
 194                 goto failed;
 195         }
 196
 197         device->dev.platform_data = bank;
 198
 199         bank->device = device;
 200
 201         if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
 202                 dev_err(&device->dev, "Cannot access device tree\n");
 203                 rc = -EFAULT;
 204                 goto failed;
 205         }
 206
 207         bank->size = resource.end - resource.start + 1;
 208
 209         if (bank->size == 0) {
 210                 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
 211                                 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 212                 rc = -ENODEV;
 213                 goto failed;
 214         }
 215
 216         dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
 217                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
 218
 219         bank->ph_addr = resource.start;
 220         bank->io_addr = (unsigned long) ioremap_flags(
 221                         bank->ph_addr, bank->size, _PAGE_NO_CACHE);
 222         if (bank->io_addr == 0) {
 223                 dev_err(&device->dev, "ioremap() failed\n");
 224                 rc = -EFAULT;
 225                 goto failed;
 226         }
 227
 228         bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
 229         if (bank->disk == NULL) {
 230                 dev_err(&device->dev, "Cannot register disk\n");
 231                 rc = -EFAULT;
 232                 goto failed;
 233         }
 234
 235         bank->disk->major = azfs_major;
 236         bank->disk->first_minor = azfs_minor;
 237         bank->disk->fops = &axon_ram_devops;
 238         bank->disk->private_data = bank;
 239         bank->disk->driverfs_dev = &device->dev;
 240
 241         sprintf(bank->disk->disk_name, "%s%d",
 242                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 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_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 254         add_disk(bank->disk);
 255
 256         bank->irq_id = irq_of_parse_and_map(device->dev.of_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         azfs_minor += bank->disk->minors;
 280
 281         return 0;
 282
 283 failed:
 284         if (bank != NULL) {
 285                 if (bank->irq_id != NO_IRQ)
 286                         free_irq(bank->irq_id, device);
 287                 if (bank->disk != NULL) {
 288                         if (bank->disk->major > 0)
 289                                 unregister_blkdev(bank->disk->major,
 290                                                 bank->disk->disk_name);
 291                         del_gendisk(bank->disk);
 292                 }
 293                 device->dev.platform_data = NULL;
 294                 if (bank->io_addr != 0)
 295                         iounmap((void __iomem *) bank->io_addr);
 296                 kfree(bank);
 297         }
 298
 299         return rc;
 300 }
 301
 302 /**
 303  * axon_ram_remove - remove() method for platform driver
 304  * @device: see of_platform_driver method
 305  */
 306 static int
 307 axon_ram_remove(struct platform_device *device)
 308 {
 309         struct axon_ram_bank *bank = device->dev.platform_data;
 310
 311         BUG_ON(!bank || !bank->disk);
 312
 313         device_remove_file(&device->dev, &dev_attr_ecc);
 314         free_irq(bank->irq_id, device);
 315         del_gendisk(bank->disk);
 316         iounmap((void __iomem *) bank->io_addr);
 317         kfree(bank);
 318
 319         return 0;
 320 }
 321
 322 static struct of_device_id axon_ram_device_id[] = {
 323         {
 324                 .type   = "dma-memory"
 325         },
 326         {}
 327 };
 328
 329 static struct of_platform_driver axon_ram_driver = {
 330         .probe          = axon_ram_probe,
 331         .remove         = axon_ram_remove,
 332         .driver = {
 333                 .name = AXON_RAM_MODULE_NAME,
 334                 .owner = THIS_MODULE,
 335                 .of_match_table = axon_ram_device_id,
 336         },
 337 };
 338
 339 /**
 340  * axon_ram_init
 341  */
 342 static int __init
 343 axon_ram_init(void)
 344 {
 345         azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 346         if (azfs_major < 0) {
 347                 printk(KERN_ERR "%s cannot become block device major number\n",
 348                                 AXON_RAM_MODULE_NAME);
 349                 return -EFAULT;
 350         }
 351         azfs_minor = 0;
 352
 353         return of_register_platform_driver(&axon_ram_driver);
 354 }
 355
 356 /**
 357  * axon_ram_exit
 358  */
 359 static void __exit
 360 axon_ram_exit(void)
 361 {
 362         of_unregister_platform_driver(&axon_ram_driver);
 363         unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 364 }
 365
 366 module_init(axon_ram_init);
 367 module_exit(axon_ram_exit);
 368
 369 MODULE_LICENSE("GPL");
 370 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 371 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");