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![Dan Williams](/assets/img/avatar_default.png)
For the purpose of communicating the optional presence of a 'struct page' for the pfn returned from ->direct_access(), introduce a type that encapsulates a page-frame-number plus flags. These flags contain the historical "page_link" encoding for a scatterlist entry, but can also denote "device memory". Where "device memory" is a set of pfns that are not part of the kernel's linear mapping by default, but are accessed via the same memory controller as ram. The motivation for this new type is large capacity persistent memory that needs struct page entries in the 'memmap' to support 3rd party DMA (i.e. O_DIRECT I/O with a persistent memory source/target). However, we also need it in support of maintaining a list of mapped inodes which need to be unmapped at driver teardown or freeze_bdev() time. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Hansen <dave@sr71.net> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
359 lines
9.2 KiB
C
359 lines
9.2 KiB
C
/*
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* (C) Copyright IBM Deutschland Entwicklung GmbH 2006
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*
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* Author: Maxim Shchetynin <maxim@de.ibm.com>
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*
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* Axon DDR2 device driver.
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* It registers one block device per Axon's DDR2 memory bank found on a system.
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* Block devices are called axonram?, their major and minor numbers are
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* available in /proc/devices, /proc/partitions or in /sys/block/axonram?/dev.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/genhd.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/irq.h>
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#include <linux/irqreturn.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/of_device.h>
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#include <linux/of_platform.h>
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#include <linux/pfn_t.h>
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#include <asm/page.h>
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#include <asm/prom.h>
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#define AXON_RAM_MODULE_NAME "axonram"
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#define AXON_RAM_DEVICE_NAME "axonram"
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#define AXON_RAM_MINORS_PER_DISK 16
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#define AXON_RAM_BLOCK_SHIFT PAGE_SHIFT
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#define AXON_RAM_BLOCK_SIZE 1 << AXON_RAM_BLOCK_SHIFT
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#define AXON_RAM_SECTOR_SHIFT 9
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#define AXON_RAM_SECTOR_SIZE 1 << AXON_RAM_SECTOR_SHIFT
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#define AXON_RAM_IRQ_FLAGS IRQF_SHARED | IRQF_TRIGGER_RISING
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static int azfs_major, azfs_minor;
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struct axon_ram_bank {
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struct platform_device *device;
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struct gendisk *disk;
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unsigned int irq_id;
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unsigned long ph_addr;
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unsigned long io_addr;
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unsigned long size;
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unsigned long ecc_counter;
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};
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static ssize_t
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axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct platform_device *device = to_platform_device(dev);
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struct axon_ram_bank *bank = device->dev.platform_data;
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BUG_ON(!bank);
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return sprintf(buf, "%ld\n", bank->ecc_counter);
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}
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static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
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/**
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* axon_ram_irq_handler - interrupt handler for Axon RAM ECC
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* @irq: interrupt ID
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* @dev: pointer to of_device
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*/
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static irqreturn_t
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axon_ram_irq_handler(int irq, void *dev)
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{
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struct platform_device *device = dev;
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struct axon_ram_bank *bank = device->dev.platform_data;
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BUG_ON(!bank);
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dev_err(&device->dev, "Correctable memory error occurred\n");
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bank->ecc_counter++;
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return IRQ_HANDLED;
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}
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/**
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* axon_ram_make_request - make_request() method for block device
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* @queue, @bio: see blk_queue_make_request()
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*/
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static blk_qc_t
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axon_ram_make_request(struct request_queue *queue, struct bio *bio)
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{
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struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
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unsigned long phys_mem, phys_end;
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void *user_mem;
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struct bio_vec vec;
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unsigned int transfered;
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struct bvec_iter iter;
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phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
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AXON_RAM_SECTOR_SHIFT);
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phys_end = bank->io_addr + bank->size;
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transfered = 0;
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bio_for_each_segment(vec, bio, iter) {
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if (unlikely(phys_mem + vec.bv_len > phys_end)) {
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bio_io_error(bio);
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return BLK_QC_T_NONE;
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}
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user_mem = page_address(vec.bv_page) + vec.bv_offset;
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if (bio_data_dir(bio) == READ)
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memcpy(user_mem, (void *) phys_mem, vec.bv_len);
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else
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memcpy((void *) phys_mem, user_mem, vec.bv_len);
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phys_mem += vec.bv_len;
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transfered += vec.bv_len;
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}
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bio_endio(bio);
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return BLK_QC_T_NONE;
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}
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/**
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* axon_ram_direct_access - direct_access() method for block device
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* @device, @sector, @data: see block_device_operations method
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*/
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static long
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axon_ram_direct_access(struct block_device *device, sector_t sector,
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void __pmem **kaddr, pfn_t *pfn)
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{
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struct axon_ram_bank *bank = device->bd_disk->private_data;
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loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
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*kaddr = (void __pmem __force *) bank->io_addr + offset;
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*pfn = phys_to_pfn_t(bank->ph_addr + offset, PFN_DEV);
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return bank->size - offset;
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}
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static const struct block_device_operations axon_ram_devops = {
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.owner = THIS_MODULE,
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.direct_access = axon_ram_direct_access
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};
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/**
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* axon_ram_probe - probe() method for platform driver
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* @device: see platform_driver method
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*/
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static int axon_ram_probe(struct platform_device *device)
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{
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static int axon_ram_bank_id = -1;
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struct axon_ram_bank *bank;
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struct resource resource;
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int rc = 0;
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axon_ram_bank_id++;
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dev_info(&device->dev, "Found memory controller on %s\n",
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device->dev.of_node->full_name);
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bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
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if (bank == NULL) {
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dev_err(&device->dev, "Out of memory\n");
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rc = -ENOMEM;
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goto failed;
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}
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device->dev.platform_data = bank;
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bank->device = device;
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if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
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dev_err(&device->dev, "Cannot access device tree\n");
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rc = -EFAULT;
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goto failed;
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}
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bank->size = resource_size(&resource);
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if (bank->size == 0) {
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dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
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AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
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rc = -ENODEV;
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goto failed;
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}
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dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
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AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
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bank->ph_addr = resource.start;
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bank->io_addr = (unsigned long) ioremap_prot(
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bank->ph_addr, bank->size, _PAGE_NO_CACHE);
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if (bank->io_addr == 0) {
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dev_err(&device->dev, "ioremap() failed\n");
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rc = -EFAULT;
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goto failed;
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}
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bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
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if (bank->disk == NULL) {
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dev_err(&device->dev, "Cannot register disk\n");
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rc = -EFAULT;
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goto failed;
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}
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bank->disk->major = azfs_major;
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bank->disk->first_minor = azfs_minor;
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bank->disk->fops = &axon_ram_devops;
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bank->disk->private_data = bank;
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bank->disk->driverfs_dev = &device->dev;
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sprintf(bank->disk->disk_name, "%s%d",
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AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
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bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
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if (bank->disk->queue == NULL) {
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dev_err(&device->dev, "Cannot register disk queue\n");
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rc = -EFAULT;
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goto failed;
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}
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set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
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blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
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blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
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add_disk(bank->disk);
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bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
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if (bank->irq_id == NO_IRQ) {
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dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
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rc = -EFAULT;
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goto failed;
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}
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rc = request_irq(bank->irq_id, axon_ram_irq_handler,
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AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
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if (rc != 0) {
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dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
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bank->irq_id = NO_IRQ;
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rc = -EFAULT;
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goto failed;
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}
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rc = device_create_file(&device->dev, &dev_attr_ecc);
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if (rc != 0) {
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dev_err(&device->dev, "Cannot create sysfs file\n");
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rc = -EFAULT;
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goto failed;
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}
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azfs_minor += bank->disk->minors;
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return 0;
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failed:
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if (bank != NULL) {
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if (bank->irq_id != NO_IRQ)
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free_irq(bank->irq_id, device);
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if (bank->disk != NULL) {
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if (bank->disk->major > 0)
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unregister_blkdev(bank->disk->major,
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bank->disk->disk_name);
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del_gendisk(bank->disk);
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}
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device->dev.platform_data = NULL;
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if (bank->io_addr != 0)
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iounmap((void __iomem *) bank->io_addr);
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kfree(bank);
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}
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return rc;
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}
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/**
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* axon_ram_remove - remove() method for platform driver
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* @device: see of_platform_driver method
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*/
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static int
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axon_ram_remove(struct platform_device *device)
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{
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struct axon_ram_bank *bank = device->dev.platform_data;
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BUG_ON(!bank || !bank->disk);
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device_remove_file(&device->dev, &dev_attr_ecc);
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free_irq(bank->irq_id, device);
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del_gendisk(bank->disk);
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iounmap((void __iomem *) bank->io_addr);
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kfree(bank);
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return 0;
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}
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static const struct of_device_id axon_ram_device_id[] = {
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{
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.type = "dma-memory"
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},
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{}
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};
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MODULE_DEVICE_TABLE(of, axon_ram_device_id);
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static struct platform_driver axon_ram_driver = {
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.probe = axon_ram_probe,
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.remove = axon_ram_remove,
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.driver = {
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.name = AXON_RAM_MODULE_NAME,
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.of_match_table = axon_ram_device_id,
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},
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};
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/**
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* axon_ram_init
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*/
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static int __init
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axon_ram_init(void)
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{
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azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
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if (azfs_major < 0) {
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printk(KERN_ERR "%s cannot become block device major number\n",
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AXON_RAM_MODULE_NAME);
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return -EFAULT;
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}
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azfs_minor = 0;
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return platform_driver_register(&axon_ram_driver);
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}
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/**
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* axon_ram_exit
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*/
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static void __exit
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axon_ram_exit(void)
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{
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platform_driver_unregister(&axon_ram_driver);
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unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
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}
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module_init(axon_ram_init);
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module_exit(axon_ram_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
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MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
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