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 blk_qc_t
 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 BLK_QC_T_NONE;
 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);
 136         return BLK_QC_T_NONE;
 137 }
 138
 139 /**
 140  * axon_ram_direct_access - direct_access() method for block device
 141  * @device, @sector, @data: see block_device_operations method
 142  */
 143 static long
 144 axon_ram_direct_access(struct block_device *device, sector_t sector,
 145                        void __pmem **kaddr, unsigned long *pfn)
 146 {
 147         struct axon_ram_bank *bank = device->bd_disk->private_data;
 148         loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
 149         void *addr = (void *)(bank->ph_addr + offset);
 150
 151         *kaddr = (void __pmem *)addr;
 152         *pfn = virt_to_phys(addr) >> PAGE_SHIFT;
 153
 154         return bank->size - offset;
 155 }
 156
 157 static const struct block_device_operations axon_ram_devops = {
 158         .owner          = THIS_MODULE,
 159         .direct_access  = axon_ram_direct_access
 160 };
 161
 162 /**
 163  * axon_ram_probe - probe() method for platform driver
 164  * @device: see platform_driver method
 165  */
 166 static int axon_ram_probe(struct platform_device *device)
 167 {
 168         static int axon_ram_bank_id = -1;
 169         struct axon_ram_bank *bank;
 170         struct resource resource;
 171         int rc = 0;
 172
 173         axon_ram_bank_id++;
 174
 175         dev_info(&device->dev, "Found memory controller on %s\n",
 176                         device->dev.of_node->full_name);
 177
 178         bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
 179         if (bank == NULL) {
 180                 dev_err(&device->dev, "Out of memory\n");
 181                 rc = -ENOMEM;
 182                 goto failed;
 183         }
 184
 185         device->dev.platform_data = bank;
 186
 187         bank->device = device;
 188
 189         if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
 190                 dev_err(&device->dev, "Cannot access device tree\n");
 191                 rc = -EFAULT;
 192                 goto failed;
 193         }
 194
 195         bank->size = resource_size(&resource);
 196
 197         if (bank->size == 0) {
 198                 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
 199                                 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 200                 rc = -ENODEV;
 201                 goto failed;
 202         }
 203
 204         dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
 205                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
 206
 207         bank->ph_addr = resource.start;
 208         bank->io_addr = (unsigned long) ioremap_prot(
 209                         bank->ph_addr, bank->size, _PAGE_NO_CACHE);
 210         if (bank->io_addr == 0) {
 211                 dev_err(&device->dev, "ioremap() failed\n");
 212                 rc = -EFAULT;
 213                 goto failed;
 214         }
 215
 216         bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
 217         if (bank->disk == NULL) {
 218                 dev_err(&device->dev, "Cannot register disk\n");
 219                 rc = -EFAULT;
 220                 goto failed;
 221         }
 222
 223         bank->disk->major = azfs_major;
 224         bank->disk->first_minor = azfs_minor;
 225         bank->disk->fops = &axon_ram_devops;
 226         bank->disk->private_data = bank;
 227         bank->disk->driverfs_dev = &device->dev;
 228
 229         sprintf(bank->disk->disk_name, "%s%d",
 230                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 231
 232         bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
 233         if (bank->disk->queue == NULL) {
 234                 dev_err(&device->dev, "Cannot register disk queue\n");
 235                 rc = -EFAULT;
 236                 goto failed;
 237         }
 238
 239         set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
 240         blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
 241         blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 242         add_disk(bank->disk);
 243
 244         bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
 245         if (bank->irq_id == NO_IRQ) {
 246                 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
 247                 rc = -EFAULT;
 248                 goto failed;
 249         }
 250
 251         rc = request_irq(bank->irq_id, axon_ram_irq_handler,
 252                         AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
 253         if (rc != 0) {
 254                 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
 255                 bank->irq_id = NO_IRQ;
 256                 rc = -EFAULT;
 257                 goto failed;
 258         }
 259
 260         rc = device_create_file(&device->dev, &dev_attr_ecc);
 261         if (rc != 0) {
 262                 dev_err(&device->dev, "Cannot create sysfs file\n");
 263                 rc = -EFAULT;
 264                 goto failed;
 265         }
 266
 267         azfs_minor += bank->disk->minors;
 268
 269         return 0;
 270
 271 failed:
 272         if (bank != NULL) {
 273                 if (bank->irq_id != NO_IRQ)
 274                         free_irq(bank->irq_id, device);
 275                 if (bank->disk != NULL) {
 276                         if (bank->disk->major > 0)
 277                                 unregister_blkdev(bank->disk->major,
 278                                                 bank->disk->disk_name);
 279                         del_gendisk(bank->disk);
 280                 }
 281                 device->dev.platform_data = NULL;
 282                 if (bank->io_addr != 0)
 283                         iounmap((void __iomem *) bank->io_addr);
 284                 kfree(bank);
 285         }
 286
 287         return rc;
 288 }
 289
 290 /**
 291  * axon_ram_remove - remove() method for platform driver
 292  * @device: see of_platform_driver method
 293  */
 294 static int
 295 axon_ram_remove(struct platform_device *device)
 296 {
 297         struct axon_ram_bank *bank = device->dev.platform_data;
 298
 299         BUG_ON(!bank || !bank->disk);
 300
 301         device_remove_file(&device->dev, &dev_attr_ecc);
 302         free_irq(bank->irq_id, device);
 303         del_gendisk(bank->disk);
 304         iounmap((void __iomem *) bank->io_addr);
 305         kfree(bank);
 306
 307         return 0;
 308 }
 309
 310 static const struct of_device_id axon_ram_device_id[] = {
 311         {
 312                 .type   = "dma-memory"
 313         },
 314         {}
 315 };
 316
 317 static struct platform_driver axon_ram_driver = {
 318         .probe          = axon_ram_probe,
 319         .remove         = axon_ram_remove,
 320         .driver = {
 321                 .name = AXON_RAM_MODULE_NAME,
 322                 .of_match_table = axon_ram_device_id,
 323         },
 324 };
 325
 326 /**
 327  * axon_ram_init
 328  */
 329 static int __init
 330 axon_ram_init(void)
 331 {
 332         azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 333         if (azfs_major < 0) {
 334                 printk(KERN_ERR "%s cannot become block device major number\n",
 335                                 AXON_RAM_MODULE_NAME);
 336                 return -EFAULT;
 337         }
 338         azfs_minor = 0;
 339
 340         return platform_driver_register(&axon_ram_driver);
 341 }
 342
 343 /**
 344  * axon_ram_exit
 345  */
 346 static void __exit
 347 axon_ram_exit(void)
 348 {
 349         platform_driver_unregister(&axon_ram_driver);
 350         unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 351 }
 352
 353 module_init(axon_ram_init);
 354 module_exit(axon_ram_exit);
 355
 356 MODULE_LICENSE("GPL");
 357 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 358 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");