dell_rbu.c

对于那些带有区码限制的DVD光驱

/*
 * dell_rbu.c
 * Bios Update driver for Dell systems
 * Author: Dell Inc
 *         Abhay Salunke <[e-mail]>
 *
 * Copyright (C) 2005 Dell Inc.
 *
 * Remote BIOS Update (rbu) driver is used for updating DELL BIOS by
 * creating entries in the /sys file systems on Linux 2.6 and higher
 * kernels. The driver supports two mechanism to update the BIOS namely
 * contiguous and packetized. Both these methods still require having some
 * application to set the CMOS bit indicating the BIOS to update itself
 * after a reboot.
 *
 * Contiguous method:
 * This driver writes the incoming data in a monolithic image by allocating
 * contiguous physical pages large enough to accommodate the incoming BIOS
 * image size.
 *
 * Packetized method:
 * The driver writes the incoming packet image by allocating a new packet
 * on every time the packet data is written. This driver requires an
 * application to break the BIOS image in to fixed sized packet chunks.
 *
 * See Documentation/dell_rbu.txt for more info.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2.0 as published by
 * the Free Software Foundation
 *
 * 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.
 */
#include <linux/config.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/blkdev.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/firmware.h>
#include <linux/dma-mapping.h>

MODULE_AUTHOR("Abhay Salunke <[e-mail]>");
MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
MODULE_LICENSE("GPL");
MODULE_VERSION("3.1");

#define BIOS_SCAN_LIMIT 0xffffffff
#define MAX_IMAGE_LENGTH 16
static struct _rbu_data {
	void *image_update_buffer;
	unsigned long image_update_buffer_size;
	unsigned long bios_image_size;
	int image_update_ordernum;
	int dma_alloc;
	spinlock_t lock;
	unsigned long packet_read_count;
	unsigned long num_packets;
	unsigned long packetsize;
	unsigned long imagesize;
	int entry_created;
} rbu_data;

static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
module_param_string(image_type, image_type, sizeof (image_type), 0);
MODULE_PARM_DESC(image_type,
	"BIOS image type. choose- mono or packet or init");

static unsigned long allocation_floor = 0x100000;
module_param(allocation_floor, ulong, 0644);
MODULE_PARM_DESC(allocation_floor,
    "Minimum address for allocations when using Packet mode");

struct packet_data {
	struct list_head list;
	size_t length;
	void *data;
	int ordernum;
};

static struct packet_data packet_data_head;

static struct platform_device *rbu_device;
static int context;
static dma_addr_t dell_rbu_dmaaddr;

static void init_packet_head(void)
{
	INIT_LIST_HEAD(&packet_data_head.list);
	rbu_data.packet_read_count = 0;
	rbu_data.num_packets = 0;
	rbu_data.packetsize = 0;
	rbu_data.imagesize = 0;
}

static int create_packet(void *data, size_t length)
{
	struct packet_data *newpacket;
	int ordernum = 0;
	int retval = 0;
	unsigned int packet_array_size = 0;
	void **invalid_addr_packet_array = NULL;
	void *packet_data_temp_buf = NULL;
	unsigned int idx = 0;

	pr_debug("create_packet: entry \n");

	if (!rbu_data.packetsize) {
		pr_debug("create_packet: packetsize not specified\n");
		retval = -EINVAL;
		goto out_noalloc;
	}

	spin_unlock(&rbu_data.lock);

	newpacket = kzalloc(sizeof (struct packet_data), GFP_KERNEL);

	if (!newpacket) {
		printk(KERN_WARNING
			"dell_rbu:%s: failed to allocate new "
			"packet\n", __FUNCTION__);
		retval = -ENOMEM;
		spin_lock(&rbu_data.lock);
		goto out_noalloc;
	}

	ordernum = get_order(length);

	/*
	 * BIOS errata mean we cannot allocate packets below 1MB or they will
	 * be overwritten by BIOS.
	 *
	 * array to temporarily hold packets
	 * that are below the allocation floor
	 *
	 * NOTE: very simplistic because we only need the floor to be at 1MB
	 *       due to BIOS errata. This shouldn't be used for higher floors
	 *       or you will run out of mem trying to allocate the array.
	 */
	packet_array_size = max(
	       		(unsigned int)(allocation_floor / rbu_data.packetsize),
			(unsigned int)1);
	invalid_addr_packet_array = kzalloc(packet_array_size * sizeof(void*),
						GFP_KERNEL);

	if (!invalid_addr_packet_array) {
		printk(KERN_WARNING
			"dell_rbu:%s: failed to allocate "
			"invalid_addr_packet_array \n",
			__FUNCTION__);
		retval = -ENOMEM;
		spin_lock(&rbu_data.lock);
		goto out_alloc_packet;
	}

	while (!packet_data_temp_buf) {
		packet_data_temp_buf = (unsigned char *)
			__get_free_pages(GFP_KERNEL, ordernum);
		if (!packet_data_temp_buf) {
			printk(KERN_WARNING
				"dell_rbu:%s: failed to allocate new "
				"packet\n", __FUNCTION__);
			retval = -ENOMEM;
			spin_lock(&rbu_data.lock);
			goto out_alloc_packet_array;
		}

		if ((unsigned long)virt_to_phys(packet_data_temp_buf)
				< allocation_floor) {
			pr_debug("packet 0x%lx below floor at 0x%lx.\n",
					(unsigned long)virt_to_phys(
						packet_data_temp_buf),
					allocation_floor);
			invalid_addr_packet_array[idx++] = packet_data_temp_buf;
			packet_data_temp_buf = NULL;
		}
	}
	spin_lock(&rbu_data.lock);

	newpacket->data = packet_data_temp_buf;

	pr_debug("create_packet: newpacket at physical addr %lx\n",
		(unsigned long)virt_to_phys(newpacket->data));

	/* packets may not have fixed size */
	newpacket->length = length;
	newpacket->ordernum = ordernum;
	++rbu_data.num_packets;

	/* initialize the newly created packet headers */
	INIT_LIST_HEAD(&newpacket->list);
	list_add_tail(&newpacket->list, &packet_data_head.list);

	memcpy(newpacket->data, data, length);

	pr_debug("create_packet: exit \n");

out_alloc_packet_array:
	/* always free packet array */
	for (;idx>0;idx--) {
		pr_debug("freeing unused packet below floor 0x%lx.\n",
			(unsigned long)virt_to_phys(
				invalid_addr_packet_array[idx-1]));
		free_pages((unsigned long)invalid_addr_packet_array[idx-1],
			ordernum);
	}
	kfree(invalid_addr_packet_array);

out_alloc_packet:
	/* if error, free data */
	if (retval)
		kfree(newpacket);

out_noalloc:
	return retval;
}

static int packetize_data(void *data, size_t length)
{
	int rc = 0;
	int done = 0;
	int packet_length;
	u8 *temp;
	u8 *end = (u8 *) data + length;
	pr_debug("packetize_data: data length %d\n", length);
	if (!rbu_data.packetsize) {
		printk(KERN_WARNING
			"dell_rbu: packetsize not specified\n");
		return -EIO;
	}

	temp = (u8 *) data;

	/* packetize the hunk */
	while (!done) {
		if ((temp + rbu_data.packetsize) < end)
			packet_length = rbu_data.packetsize;
		else {
			/* this is the last packet */
			packet_length = end - temp;
			done = 1;
		}

		if ((rc = create_packet(temp, packet_length)))
			return rc;

		pr_debug("%lu:%lu\n", temp, (end - temp));
		temp += packet_length;
	}

	rbu_data.imagesize = length;

	return rc;
}

static int do_packet_read(char *data, struct list_head *ptemp_list,
	int length, int bytes_read, int *list_read_count)
{
	void *ptemp_buf;
	struct packet_data *newpacket = NULL;
	int bytes_copied = 0;
	int j = 0;

	newpacket = list_entry(ptemp_list, struct packet_data, list);
	*list_read_count += newpacket->length;

	if (*list_read_count > bytes_read) {
		/* point to the start of unread data */
		j = newpacket->length - (*list_read_count - bytes_read);
		/* point to the offset in the packet buffer */
		ptemp_buf = (u8 *) newpacket->data + j;
		/*
		 * check if there is enough room in
		 * * the incoming buffer
		 */
		if (length > (*list_read_count - bytes_read))
			/*
			 * copy what ever is there in this
			 * packet and move on
			 */
			bytes_copied = (*list_read_count - bytes_read);
		else
			/* copy the remaining */
			bytes_copied = length;
		memcpy(data, ptemp_buf, bytes_copied);
	}
	return bytes_copied;
}

static int packet_read_list(char *data, size_t * pread_length)
{
	struct list_head *ptemp_list;
	int temp_count = 0;
	int bytes_copied = 0;
	int bytes_read = 0;
	int remaining_bytes = 0;
	char *pdest = data;

	/* check if we have any packets */
	if (0 == rbu_data.num_packets)
		return -ENOMEM;

	remaining_bytes = *pread_length;
	bytes_read = rbu_data.packet_read_count;

	ptemp_list = (&packet_data_head.list)->next;
	while (!list_empty(ptemp_list)) {
		bytes_copied = do_packet_read(pdest, ptemp_list,
			remaining_bytes, bytes_read, &temp_count);
		remaining_bytes -= bytes_copied;
		bytes_read += bytes_copied;
		pdest += bytes_copied;
		/*
		 * check if we reached end of buffer before reaching the
		 * last packet
		 */
		if (remaining_bytes == 0)
			break;

		ptemp_list = ptemp_list->next;
	}
	/*finally set the bytes read */
	*pread_length = bytes_read - rbu_data.packet_read_count;
	rbu_data.packet_read_count = bytes_read;
	return 0;
}

static void packet_empty_list(void)
{
	struct list_head *ptemp_list;
	struct list_head *pnext_list;
	struct packet_data *newpacket;

	ptemp_list = (&packet_data_head.list)->next;
	while (!list_empty(ptemp_list)) {
		newpacket =
			list_entry(ptemp_list, struct packet_data, list);
		pnext_list = ptemp_list->next;
		list_del(ptemp_list);
		ptemp_list = pnext_list;
		/*
		 * zero out the RBU packet memory before freeing
		 * to make sure there are no stale RBU packets left in memory
		 */
		memset(newpacket->data, 0, rbu_data.packetsize);
		free_pages((unsigned long) newpacket->data,
			newpacket->ordernum);
		kfree(newpacket);
	}
	rbu_data.packet_read_count = 0;
	rbu_data.num_packets = 0;
	rbu_data.imagesize = 0;
}

/*
 * img_update_free: Frees the buffer allocated for storing BIOS image
 * Always called with lock held and returned with lock held
 */
static void img_update_free(void)
{
	if (!rbu_data.image_update_buffer)
		return;
	/*
	 * zero out this buffer before freeing it to get rid of any stale
	 * BIOS image copied in memory.
	 */
	memset(rbu_data.image_update_buffer, 0,
		rbu_data.image_update_buffer_size);
	if (rbu_data.dma_alloc == 1)
		dma_free_coherent(NULL, rbu_data.bios_image_size,
			rbu_data.image_update_buffer, dell_rbu_dmaaddr);
	else
		free_pages((unsigned long) rbu_data.image_update_buffer,
			rbu_data.image_update_ordernum);

	/*