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/dax.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 #include <linux/pfn_t.h>
  48 #include <linux/uio.h>
  49
  50 #include <asm/page.h>
  51 #include <asm/prom.h>
  52
  53 #define AXON_RAM_MODULE_NAME            "axonram"
  54 #define AXON_RAM_DEVICE_NAME            "axonram"
  55 #define AXON_RAM_MINORS_PER_DISK        16
  56 #define AXON_RAM_BLOCK_SHIFT            PAGE_SHIFT
  57 #define AXON_RAM_BLOCK_SIZE             1 << AXON_RAM_BLOCK_SHIFT
  58 #define AXON_RAM_SECTOR_SHIFT           9
  59 #define AXON_RAM_SECTOR_SIZE            1 << AXON_RAM_SECTOR_SHIFT
  60 #define AXON_RAM_IRQ_FLAGS              IRQF_SHARED | IRQF_TRIGGER_RISING
  61
  62 static int azfs_major, azfs_minor;
  63
  64 struct axon_ram_bank {
  65         struct platform_device  *device;
  66         struct gendisk          *disk;
  67         struct dax_device       *dax_dev;
  68         unsigned int            irq_id;
  69         unsigned long           ph_addr;
  70         unsigned long           io_addr;
  71         unsigned long           size;
  72         unsigned long           ecc_counter;
  73 };
  74
  75 static ssize_t
  76 axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
  77 {
  78         struct platform_device *device = to_platform_device(dev);
  79         struct axon_ram_bank *bank = device->dev.platform_data;
  80
  81         BUG_ON(!bank);
  82
  83         return sprintf(buf, "%ld\n", bank->ecc_counter);
  84 }
  85
  86 static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
  87
  88 /**
  89  * axon_ram_irq_handler - interrupt handler for Axon RAM ECC
  90  * @irq: interrupt ID
  91  * @dev: pointer to of_device
  92  */
  93 static irqreturn_t
  94 axon_ram_irq_handler(int irq, void *dev)
  95 {
  96         struct platform_device *device = dev;
  97         struct axon_ram_bank *bank = device->dev.platform_data;
  98
  99         BUG_ON(!bank);
 100
 101         dev_err(&device->dev, "Correctable memory error occurred\n");
 102         bank->ecc_counter++;
 103         return IRQ_HANDLED;
 104 }
 105
 106 /**
 107  * axon_ram_make_request - make_request() method for block device
 108  * @queue, @bio: see blk_queue_make_request()
 109  */
 110 static blk_qc_t
 111 axon_ram_make_request(struct request_queue *queue, struct bio *bio)
 112 {
 113         struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
 114         unsigned long phys_mem, phys_end;
 115         void *user_mem;
 116         struct bio_vec vec;
 117         unsigned int transfered;
 118         struct bvec_iter iter;
 119
 120         phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
 121                                     AXON_RAM_SECTOR_SHIFT);
 122         phys_end = bank->io_addr + bank->size;
 123         transfered = 0;
 124         bio_for_each_segment(vec, bio, iter) {
 125                 if (unlikely(phys_mem + vec.bv_len > phys_end)) {
 126                         bio_io_error(bio);
 127                         return BLK_QC_T_NONE;
 128                 }
 129
 130                 user_mem = page_address(vec.bv_page) + vec.bv_offset;
 131                 if (bio_data_dir(bio) == READ)
 132                         memcpy(user_mem, (void *) phys_mem, vec.bv_len);
 133                 else
 134                         memcpy((void *) phys_mem, user_mem, vec.bv_len);
 135
 136                 phys_mem += vec.bv_len;
 137                 transfered += vec.bv_len;
 138         }
 139         bio_endio(bio);
 140         return BLK_QC_T_NONE;
 141 }
 142
 143 static const struct block_device_operations axon_ram_devops = {
 144         .owner          = THIS_MODULE,
 145 };
 146
 147 static long
 148 __axon_ram_direct_access(struct axon_ram_bank *bank, pgoff_t pgoff, long nr_pages,
 149                        void **kaddr, pfn_t *pfn)
 150 {
 151         resource_size_t offset = pgoff * PAGE_SIZE;
 152
 153         *kaddr = (void *) bank->io_addr + offset;
 154         *pfn = phys_to_pfn_t(bank->ph_addr + offset, PFN_DEV);
 155         return (bank->size - offset) / PAGE_SIZE;
 156 }
 157
 158 static long
 159 axon_ram_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 160                        void **kaddr, pfn_t *pfn)
 161 {
 162         struct axon_ram_bank *bank = dax_get_private(dax_dev);
 163
 164         return __axon_ram_direct_access(bank, pgoff, nr_pages, kaddr, pfn);
 165 }
 166
 167 static size_t axon_ram_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 168                 void *addr, size_t bytes, struct iov_iter *i)
 169 {
 170         return copy_from_iter(addr, bytes, i);
 171 }
 172
 173 static const struct dax_operations axon_ram_dax_ops = {
 174         .direct_access = axon_ram_dax_direct_access,
 175         .copy_from_iter = axon_ram_copy_from_iter,
 176 };
 177
 178 /**
 179  * axon_ram_probe - probe() method for platform driver
 180  * @device: see platform_driver method
 181  */
 182 static int axon_ram_probe(struct platform_device *device)
 183 {
 184         static int axon_ram_bank_id = -1;
 185         struct axon_ram_bank *bank;
 186         struct resource resource;
 187         int rc = 0;
 188
 189         axon_ram_bank_id++;
 190
 191         dev_info(&device->dev, "Found memory controller on %s\n",
 192                         device->dev.of_node->full_name);
 193
 194         bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
 195         if (bank == NULL) {
 196                 dev_err(&device->dev, "Out of memory\n");
 197                 rc = -ENOMEM;
 198                 goto failed;
 199         }
 200
 201         device->dev.platform_data = bank;
 202
 203         bank->device = device;
 204
 205         if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
 206                 dev_err(&device->dev, "Cannot access device tree\n");
 207                 rc = -EFAULT;
 208                 goto failed;
 209         }
 210
 211         bank->size = resource_size(&resource);
 212
 213         if (bank->size == 0) {
 214                 dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
 215                                 AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 216                 rc = -ENODEV;
 217                 goto failed;
 218         }
 219
 220         dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
 221                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
 222
 223         bank->ph_addr = resource.start;
 224         bank->io_addr = (unsigned long) ioremap_prot(
 225                         bank->ph_addr, bank->size, _PAGE_NO_CACHE);
 226         if (bank->io_addr == 0) {
 227                 dev_err(&device->dev, "ioremap() failed\n");
 228                 rc = -EFAULT;
 229                 goto failed;
 230         }
 231
 232         bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
 233         if (bank->disk == NULL) {
 234                 dev_err(&device->dev, "Cannot register disk\n");
 235                 rc = -EFAULT;
 236                 goto failed;
 237         }
 238
 239
 240         bank->disk->major = azfs_major;
 241         bank->disk->first_minor = azfs_minor;
 242         bank->disk->fops = &axon_ram_devops;
 243         bank->disk->private_data = bank;
 244
 245         sprintf(bank->disk->disk_name, "%s%d",
 246                         AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
 247
 248         bank->dax_dev = alloc_dax(bank, bank->disk->disk_name,
 249                         &axon_ram_dax_ops);
 250         if (!bank->dax_dev) {
 251                 rc = -ENOMEM;
 252                 goto failed;
 253         }
 254
 255         bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
 256         if (bank->disk->queue == NULL) {
 257                 dev_err(&device->dev, "Cannot register disk queue\n");
 258                 rc = -EFAULT;
 259                 goto failed;
 260         }
 261
 262         set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
 263         blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
 264         blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
 265         device_add_disk(&device->dev, bank->disk);
 266
 267         bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
 268         if (!bank->irq_id) {
 269                 dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
 270                 rc = -EFAULT;
 271                 goto failed;
 272         }
 273
 274         rc = request_irq(bank->irq_id, axon_ram_irq_handler,
 275                         AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
 276         if (rc != 0) {
 277                 dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
 278                 bank->irq_id = 0;
 279                 rc = -EFAULT;
 280                 goto failed;
 281         }
 282
 283         rc = device_create_file(&device->dev, &dev_attr_ecc);
 284         if (rc != 0) {
 285                 dev_err(&device->dev, "Cannot create sysfs file\n");
 286                 rc = -EFAULT;
 287                 goto failed;
 288         }
 289
 290         azfs_minor += bank->disk->minors;
 291
 292         return 0;
 293
 294 failed:
 295         if (bank != NULL) {
 296                 if (bank->irq_id)
 297                         free_irq(bank->irq_id, device);
 298                 if (bank->disk != NULL) {
 299                         if (bank->disk->major > 0)
 300                                 unregister_blkdev(bank->disk->major,
 301                                                 bank->disk->disk_name);
 302                         if (bank->disk->flags & GENHD_FL_UP)
 303                                 del_gendisk(bank->disk);
 304                         put_disk(bank->disk);
 305                 }
 306                 kill_dax(bank->dax_dev);
 307                 put_dax(bank->dax_dev);
 308                 device->dev.platform_data = NULL;
 309                 if (bank->io_addr != 0)
 310                         iounmap((void __iomem *) bank->io_addr);
 311                 kfree(bank);
 312         }
 313
 314         return rc;
 315 }
 316
 317 /**
 318  * axon_ram_remove - remove() method for platform driver
 319  * @device: see of_platform_driver method
 320  */
 321 static int
 322 axon_ram_remove(struct platform_device *device)
 323 {
 324         struct axon_ram_bank *bank = device->dev.platform_data;
 325
 326         BUG_ON(!bank || !bank->disk);
 327
 328         device_remove_file(&device->dev, &dev_attr_ecc);
 329         free_irq(bank->irq_id, device);
 330         kill_dax(bank->dax_dev);
 331         put_dax(bank->dax_dev);
 332         del_gendisk(bank->disk);
 333         put_disk(bank->disk);
 334         iounmap((void __iomem *) bank->io_addr);
 335         kfree(bank);
 336
 337         return 0;
 338 }
 339
 340 static const struct of_device_id axon_ram_device_id[] = {
 341         {
 342                 .type   = "dma-memory"
 343         },
 344         {}
 345 };
 346 MODULE_DEVICE_TABLE(of, axon_ram_device_id);
 347
 348 static struct platform_driver axon_ram_driver = {
 349         .probe          = axon_ram_probe,
 350         .remove         = axon_ram_remove,
 351         .driver = {
 352                 .name = AXON_RAM_MODULE_NAME,
 353                 .of_match_table = axon_ram_device_id,
 354         },
 355 };
 356
 357 /**
 358  * axon_ram_init
 359  */
 360 static int __init
 361 axon_ram_init(void)
 362 {
 363         azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 364         if (azfs_major < 0) {
 365                 printk(KERN_ERR "%s cannot become block device major number\n",
 366                                 AXON_RAM_MODULE_NAME);
 367                 return -EFAULT;
 368         }
 369         azfs_minor = 0;
 370
 371         return platform_driver_register(&axon_ram_driver);
 372 }
 373
 374 /**
 375  * axon_ram_exit
 376  */
 377 static void __exit
 378 axon_ram_exit(void)
 379 {
 380         platform_driver_unregister(&axon_ram_driver);
 381         unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
 382 }
 383
 384 module_init(axon_ram_init);
 385 module_exit(axon_ram_exit);
 386
 387 MODULE_LICENSE("GPL");
 388 MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
 389 MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");