![Markus Elfring](/assets/img/avatar_default.png)
The local variable "rc" will eventually be set only to an error code. Thus omit the explicit initialisation at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
384 lines
9.7 KiB
C
384 lines
9.7 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/dax.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 <linux/uio.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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struct dax_device *dax_dev;
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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_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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static const struct block_device_operations axon_ram_devops = {
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.owner = THIS_MODULE,
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};
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static long
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__axon_ram_direct_access(struct axon_ram_bank *bank, pgoff_t pgoff, long nr_pages,
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void **kaddr, pfn_t *pfn)
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{
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resource_size_t offset = pgoff * PAGE_SIZE;
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*kaddr = (void *) 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) / PAGE_SIZE;
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}
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static long
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axon_ram_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
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void **kaddr, pfn_t *pfn)
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{
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struct axon_ram_bank *bank = dax_get_private(dax_dev);
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return __axon_ram_direct_access(bank, pgoff, nr_pages, kaddr, pfn);
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}
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static size_t axon_ram_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
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void *addr, size_t bytes, struct iov_iter *i)
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{
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return copy_from_iter(addr, bytes, i);
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}
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static const struct dax_operations axon_ram_dax_ops = {
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.direct_access = axon_ram_dax_direct_access,
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.copy_from_iter = axon_ram_copy_from_iter,
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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;
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axon_ram_bank_id++;
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dev_info(&device->dev, "Found memory controller on %pOF\n",
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device->dev.of_node);
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bank = kzalloc(sizeof(*bank), GFP_KERNEL);
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if (!bank)
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return -ENOMEM;
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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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sprintf(bank->disk->disk_name, "%s%d",
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AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
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bank->dax_dev = alloc_dax(bank, bank->disk->disk_name,
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&axon_ram_dax_ops);
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if (!bank->dax_dev) {
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rc = -ENOMEM;
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goto failed;
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}
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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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device_add_disk(&device->dev, 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) {
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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 = 0;
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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->irq_id)
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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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if (bank->disk->flags & GENHD_FL_UP)
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del_gendisk(bank->disk);
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put_disk(bank->disk);
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}
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kill_dax(bank->dax_dev);
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put_dax(bank->dax_dev);
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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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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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kill_dax(bank->dax_dev);
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put_dax(bank->dax_dev);
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del_gendisk(bank->disk);
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put_disk(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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