/*
* (C) Copyright IBM Deutschland Entwicklung GmbH 2006
*
* Author: Maxim Shchetynin <maxim@de.ibm.com>
*
* Axon DDR2 device driver.
* It registers one block device per Axon's DDR2 memory bank found on a system.
* Block devices are called axonram?, their major and minor numbers are
* available in /proc/devices, /proc/partitions or in /sys/block/axonram?/dev.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <asm/page.h>
#include <asm/prom.h>
#define AXON_RAM_MODULE_NAME "axonram"
#define AXON_RAM_DEVICE_NAME "axonram"
#define AXON_RAM_MINORS_PER_DISK 16
#define AXON_RAM_BLOCK_SHIFT PAGE_SHIFT
#define AXON_RAM_BLOCK_SIZE 1 << AXON_RAM_BLOCK_SHIFT
#define AXON_RAM_SECTOR_SHIFT 9
#define AXON_RAM_SECTOR_SIZE 1 << AXON_RAM_SECTOR_SHIFT
#define AXON_RAM_IRQ_FLAGS IRQF_SHARED | IRQF_TRIGGER_RISING
static int azfs_major, azfs_minor;
struct axon_ram_bank {
struct platform_device *device;
struct gendisk *disk;
unsigned int irq_id;
unsigned long ph_addr;
unsigned long io_addr;
unsigned long size;
unsigned long ecc_counter;
};
static ssize_t
axon_ram_sysfs_ecc(struct device *dev, struct device_attribute *attr, char *buf)
{
struct platform_device *device = to_platform_device(dev);
struct axon_ram_bank *bank = device->dev.platform_data;
BUG_ON(!bank);
return sprintf(buf, "%ld\n", bank->ecc_counter);
}
static DEVICE_ATTR(ecc, S_IRUGO, axon_ram_sysfs_ecc, NULL);
/**
* axon_ram_irq_handler - interrupt handler for Axon RAM ECC
* @irq: interrupt ID
* @dev: pointer to of_device
*/
static irqreturn_t
axon_ram_irq_handler(int irq, void *dev)
{
struct platform_device *device = dev;
struct axon_ram_bank *bank = device->dev.platform_data;
BUG_ON(!bank);
dev_err(&device->dev, "Correctable memory error occurred\n");
bank->ecc_counter++;
return IRQ_HANDLED;
}
/**
* axon_ram_make_request - make_request() method for block device
* @queue, @bio: see blk_queue_make_request()
*/
static void
axon_ram_make_request(struct request_queue *queue, struct bio *bio)
{
struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
unsigned long phys_mem, phys_end;
void *user_mem;
struct bio_vec vec;
unsigned int transfered;
struct bvec_iter iter;
phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
AXON_RAM_SECTOR_SHIFT);
phys_end = bank->io_addr + bank->size;
transfered = 0;
bio_for_each_segment(vec, bio, iter) {
if (unlikely(phys_mem + vec.bv_len > phys_end)) {
bio_io_error(bio);
return;
}
user_mem = page_address(vec.bv_page) + vec.bv_offset;
if (bio_data_dir(bio) == READ)
memcpy(user_mem, (void *) phys_mem, vec.bv_len);
else
memcpy((void *) phys_mem, user_mem, vec.bv_len);
phys_mem += vec.bv_len;
transfered += vec.bv_len;
}
bio_endio(bio, 0);
}
/**
* axon_ram_direct_access - direct_access() method for block device
* @device, @sector, @data: see block_device_operations method
*/
static long
axon_ram_direct_access(struct block_device *device, sector_t sector,
void **kaddr, unsigned long *pfn, long size)
{
struct axon_ram_bank *bank = device->bd_disk->private_data;
loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
*kaddr = (void *)(bank->ph_addr + offset);
*pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
return bank->size - offset;
}
static const struct block_device_operations axon_ram_devops = {
.owner = THIS_MODULE,
.direct_access = axon_ram_direct_access
};
/**
* axon_ram_probe - probe() method for platform driver
* @device: see platform_driver method
*/
static int axon_ram_probe(struct platform_device *device)
{
static int axon_ram_bank_id = -1;
struct axon_ram_bank *bank;
struct resource resource;
int rc = 0;
axon_ram_bank_id++;
dev_info(&device->dev, "Found memory controller on %s\n",
device->dev.of_node->full_name);
bank = kzalloc(sizeof(struct axon_ram_bank), GFP_KERNEL);
if (bank == NULL) {
dev_err(&device->dev, "Out of memory\n");
rc = -ENOMEM;
goto failed;
}
device->dev.platform_data = bank;
bank->device = device;
if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
dev_err(&device->dev, "Cannot access device tree\n");
rc = -EFAULT;
goto failed;
}
bank->size = resource_size(&resource);
if (bank->size == 0) {
dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
rc = -ENODEV;
goto failed;
}
dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
bank->ph_addr = resource.start;
bank->io_addr = (unsigned long) ioremap_prot(
bank->ph_addr, bank->size, _PAGE_NO_CACHE);
if (bank->io_addr == 0) {
dev_err(&device->dev, "ioremap() failed\n");
rc = -EFAULT;
goto failed;
}
bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
if (bank->disk == NULL) {
dev_err(&device->dev, "Cannot register disk\n");
rc = -EFAULT;
goto failed;
}
bank->disk->major = azfs_major;
bank->disk->first_minor = azfs_minor;
bank->disk->fops = &axon_ram_devops;
bank->disk->private_data = bank;
bank->disk->driverfs_dev = &device->dev;
sprintf(bank->disk->disk_name, "%s%d",
AXON_RAM_DEVICE_NAME, axon_ram_bank_id);
bank->disk->queue = blk_alloc_queue(GFP_KERNEL);
if (bank->disk->queue == NULL) {
dev_err(&device->dev, "Cannot register disk queue\n");
rc = -EFAULT;
goto failed;
}
set_capacity(bank->disk, bank->size >> AXON_RAM_SECTOR_SHIFT);
blk_queue_make_request(bank->disk->queue, axon_ram_make_request);
blk_queue_logical_block_size(bank->disk->queue, AXON_RAM_SECTOR_SIZE);
add_disk(bank->disk);
bank->irq_id = irq_of_parse_and_map(device->dev.of_node, 0);
if (bank->irq_id == NO_IRQ) {
dev_err(&device->dev, "Cannot access ECC interrupt ID\n");
rc = -EFAULT;
goto failed;
}
rc = request_irq(bank->irq_id, axon_ram_irq_handler,
AXON_RAM_IRQ_FLAGS, bank->disk->disk_name, device);
if (rc != 0) {
dev_err(&device->dev, "Cannot register ECC interrupt handler\n");
bank->irq_id = NO_IRQ;
rc = -EFAULT;
goto failed;
}
rc = device_create_file(&device->dev, &dev_attr_ecc);
if (rc != 0) {
dev_err(&device->dev, "Cannot create sysfs file\n");
rc = -EFAULT;
goto failed;
}
azfs_minor += bank->disk->minors;
return 0;
failed:
if (bank != NULL) {
if (bank->irq_id != NO_IRQ)
free_irq(bank->irq_id, device);
if (bank->disk != NULL) {
if (bank->disk->major > 0)
unregister_blkdev(bank->disk->major,
bank->disk->disk_name);
del_gendisk(bank->disk);
}
device->dev.platform_data = NULL;
if (bank->io_addr != 0)
iounmap((void __iomem *) bank->io_addr);
kfree(bank);
}
return rc;
}
/**
* axon_ram_remove - remove() method for platform driver
* @device: see of_platform_driver method
*/
static int
axon_ram_remove(struct platform_device *device)
{
struct axon_ram_bank *bank = device->dev.platform_data;
BUG_ON(!bank || !bank->disk);
device_remove_file(&device->dev, &dev_attr_ecc);
free_irq(bank->irq_id, device);
del_gendisk(bank->disk);
iounmap((void __iomem *) bank->io_addr);
kfree(bank);
return 0;
}
static const struct of_device_id axon_ram_device_id[] = {
{
.type = "dma-memory"
},
{}
};
static struct platform_driver axon_ram_driver = {
.probe = axon_ram_probe,
.remove = axon_ram_remove,
.driver = {
.name = AXON_RAM_MODULE_NAME,
.of_match_table = axon_ram_device_id,
},
};
/**
* axon_ram_init
*/
static int __init
axon_ram_init(void)
{
azfs_major = register_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
if (azfs_major < 0) {
printk(KERN_ERR "%s cannot become block device major number\n",
AXON_RAM_MODULE_NAME);
return -EFAULT;
}
azfs_minor = 0;
return platform_driver_register(&axon_ram_driver);
}
/**
* axon_ram_exit
*/
static void __exit
axon_ram_exit(void)
{
platform_driver_unregister(&axon_ram_driver);
unregister_blkdev(azfs_major, AXON_RAM_DEVICE_NAME);
}
module_init(axon_ram_init);
module_exit(axon_ram_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Maxim Shchetynin <maxim@de.ibm.com>");
MODULE_DESCRIPTION("Axon DDR2 RAM device driver for IBM Cell BE");
