[PATCH] dell_rbu: new Dell BIOS update driver

Purpose:

Demonstrate the usage of the new open sourced rbu (Remote BIOS Update) driver

for updating BIOS images on Dell servers and desktops.

Scope:

This document discusses the functionality of the rbu driver only.

It does not cover the support needed from aplications to enable the BIOS to

update itself with the image downloaded in to the memory.

Overview:

This driver works with Dell OpenManage or Dell Update Packages for updating

the BIOS on Dell servers (starting from servers sold since 1999), desktops

and notebooks (starting from those sold in 2005).

Please go to  http://support.dell.com register and you can find info on

OpenManage and Dell Update packages (DUP).

Dell_RBU driver supports BIOS update using the monilothic image and packetized

image methods. In case of moniolithic the driver allocates a contiguous chunk

of physical pages having the BIOS image. In case of packetized the app

using the driver breaks the image in to packets of fixed sizes and the driver

would place each packet in contiguous physical memory. The driver also

maintains a link list of packets for reading them back.

If the dell_rbu driver is unloaded all the allocated memory is freed.

The rbu driver needs to have an application which will inform the BIOS to

enable the update in the next system reboot.

The user should not unload the rbu driver after downloading the BIOS image

or updating.

The driver load creates the following directories under the /sys file system.

/sys/class/firmware/dell_rbu/loading

/sys/class/firmware/dell_rbu/data

/sys/devices/platform/dell_rbu/image_type

/sys/devices/platform/dell_rbu/data

The driver supports two types of update mechanism; monolithic and packetized.

These update mechanism depends upon the BIOS currently running on the system.

Most of the Dell systems support a monolithic update where the BIOS image is

copied to a single contiguous block of physical memory.

In case of packet mechanism the single memory can be broken in smaller chuks

of contiguous memory and the BIOS image is scattered in these packets.

By default the driver uses monolithic memory for the update type. This can be

changed to contiguous during the driver load time by specifying the load

parameter image_type=packet.  This can also be changed later as below

echo packet > /sys/devices/platform/dell_rbu/image_type

Do the steps below to download the BIOS image.

1) echo 1 > /sys/class/firmware/dell_rbu/loading

2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data

3) echo 0 > /sys/class/firmware/dell_rbu/loading

The /sys/class/firmware/dell_rbu/ entries will remain till the following is

done.

echo -1 > /sys/class/firmware/dell_rbu/loading

Until this step is completed the drivr cannot be unloaded.

Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to

read back the image downloaded. This is useful in case of packet update

mechanism where the above steps 1,2,3 will repeated for every packet.

By reading the /sys/devices/platform/dell_rbu/data file all packet data

downloaded can be verified in a single file.

The packets are arranged in this file one after the other in a FIFO order.

NOTE:

This driver requires a patch for firmware_class.c which has the addition

of request_firmware_nowait_nohotplug function to wortk

Also after updating the BIOS image an user mdoe application neeeds to execute

code which message the BIOS update request to the BIOS. So on the next reboot

the BIOS knows about the new image downloaded and it updates it self.

Also don't unload the rbu drive if the image has to be updated.

	  See <http://www.dig64.org/specifications/DIG64_HCDPv20_042804.pdf>

config DELL_RBU

	tristate "BIOS update support for DELL systems via sysfs"

	select FW_LOADER

	help

	 Say m if you want to have the option of updating the BIOS for your

	 DELL system. Note you need a Dell OpenManage or Dell Update package (DUP)

	 supporting application to comunicate with the BIOS regarding the new

	 image for the image update to take effect.

	 See <file:Documentation/dell_rbu.txt> for more details on the driver.

endmenu

obj-$(CONFIG_EDD)             	+= edd.o

obj-$(CONFIG_EFI_VARS)		+= efivars.o

obj-$(CONFIG_EFI_PCDP)		+= pcdp.o

obj-$(CONFIG_DELL_RBU)          += dell_rbu.o

/*

 * dell_rbu.c

 * Bios Update driver for Dell systems

 * Author: Dell Inc

 *         Abhay Salunke <abhay_salunke@dell.com>

 *

 * 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/version.h>

#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/device.h>

#include <linux/spinlock.h>

#include <linux/moduleparam.h>

#include <linux/firmware.h>

#include <linux/dma-mapping.h>

MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");

MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");

MODULE_LICENSE("GPL");

MODULE_VERSION("1.0");

#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 packet_write_count;

	unsigned long num_packets;

	unsigned long packetsize;

} rbu_data;

static char image_type[MAX_IMAGE_LENGTH] = "mono";

module_param_string(image_type, image_type, sizeof(image_type), 0);

MODULE_PARM_DESC(image_type, "BIOS image type. choose- mono or packet");

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_write_count = 0;

	rbu_data.packet_read_count = 0;

	rbu_data.num_packets = 0;

	rbu_data.packetsize = 0;

}

static int fill_last_packet(void *data, size_t length)

{

	struct list_head *ptemp_list;

	struct packet_data *packet = NULL;

	int packet_count = 0;

	pr_debug("fill_last_packet: entry \n");

	if (!rbu_data.num_packets) {

		pr_debug("fill_last_packet: num_packets=0\n");

		return -ENOMEM;

	}

	packet_count = rbu_data.num_packets;

	ptemp_list = (&packet_data_head.list)->prev;

	packet = list_entry(ptemp_list, struct packet_data, list);

	if ((rbu_data.packet_write_count + length) > rbu_data.packetsize) {

		pr_debug("dell_rbu:%s: packet size data "

			 "overrun\n", __FUNCTION__);

		return -EINVAL;

	}

	pr_debug("fill_last_packet : buffer = %p\n", packet->data);

	memcpy((packet->data + rbu_data.packet_write_count), data, length);

	if ((rbu_data.packet_write_count + length) == rbu_data.packetsize) {

		/*

		 * this was the last data chunk in the packet

		 * so reinitialize the packet data counter to zero

		 */

		rbu_data.packet_write_count = 0;

	} else

		rbu_data.packet_write_count += length;

	pr_debug("fill_last_packet: exit \n");

	return 0;

}

static int create_packet(size_t length)

{

	struct packet_data *newpacket;

	int ordernum = 0;

	pr_debug("create_packet: entry \n");

	if (!rbu_data.packetsize) {

		pr_debug("create_packet: packetsize not specified\n");

		return -EINVAL;

	}

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

	if (!newpacket) {

		printk(KERN_WARNING

		       "dell_rbu:%s: failed to allocate new "

		       "packet\n", __FUNCTION__);

		return -ENOMEM;

	}

	ordernum = get_order(length);

	/*

	 * there is no upper limit on memory

	 * address for packetized mechanism

	 */

	newpacket->data = (unsigned char *)__get_free_pages(GFP_KERNEL,

							    ordernum);

	pr_debug("create_packet: newpacket %p\n", newpacket->data);

	if (!newpacket->data) {

		printk(KERN_WARNING

		       "dell_rbu:%s: failed to allocate new "

		       "packet\n", __FUNCTION__);

		kfree(newpacket);

		return -ENOMEM;

	}

	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);

	/*

	 * packets have fixed size

	 */

	newpacket->length = rbu_data.packetsize;

	pr_debug("create_packet: exit \n");

	return 0;

}

static int packetize_data(void *data, size_t length)

{

	int rc = 0;

	if (!rbu_data.packet_write_count) {

		if ((rc = create_packet(length)))

			return rc;

	}

	if ((rc = fill_last_packet(data, length)))

		return rc;

	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_write_count = 0;

	rbu_data.packet_read_count = 0;

	rbu_data.num_packets = 0;

	rbu_data.packetsize = 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);

	/*

	 * Re-initialize the rbu_data variables after a free

	 */

	rbu_data.image_update_ordernum = -1;

	rbu_data.image_update_buffer = NULL;

	rbu_data.image_update_buffer_size = 0;

	rbu_data.bios_image_size = 0;

	rbu_data.dma_alloc = 0;

}

/*

 * img_update_realloc: This function allocates the contiguous pages to

 * accommodate the requested size of data. The memory address and size

 * values are stored globally and on every call to this function the new

 * size is checked to see if more data is required than the existing size.

 * If true the previous memory is freed and new allocation is done to

 * accommodate the new size. If the incoming size is less then than the

 * already allocated size, then that memory is reused. This function is

 * called with lock held and returns with lock held.

 */

static int img_update_realloc(unsigned long size)

{

	unsigned char *image_update_buffer = NULL;

	unsigned long rc;

	unsigned long img_buf_phys_addr;

	int ordernum;

	int dma_alloc = 0;

	/*

	 * check if the buffer of sufficient size has been

	 * already allocated

	 */

	if (rbu_data.image_update_buffer_size >= size) {

		/*

		 * check for corruption

		 */

		if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {

			printk(KERN_ERR "dell_rbu:%s: corruption "

			       "check failed\n", __FUNCTION__);

			return -EINVAL;

		}

		/*

		 * we have a valid pre-allocated buffer with

		 * sufficient size

		 */

		return 0;

	}

	/*

	 * free any previously allocated buffer

	 */

	img_update_free();

	spin_unlock(&rbu_data.lock);

	ordernum = get_order(size);

	image_update_buffer =

	    (unsigned char *)__get_free_pages(GFP_KERNEL, ordernum);

	img_buf_phys_addr =

	    (unsigned long)virt_to_phys(image_update_buffer);

	if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {

		free_pages((unsigned long)image_update_buffer, ordernum);

		ordernum = -1;

		image_update_buffer = dma_alloc_coherent(NULL, size,

							 &dell_rbu_dmaaddr,

							 GFP_KERNEL);

		dma_alloc = 1;

	}

	spin_lock(&rbu_data.lock);

	if (image_update_buffer != NULL) {

		rbu_data.image_update_buffer = image_update_buffer;

		rbu_data.image_update_buffer_size = size;

		rbu_data.bios_image_size =

		    rbu_data.image_update_buffer_size;

		rbu_data.image_update_ordernum = ordernum;

		rbu_data.dma_alloc = dma_alloc;

		rc = 0;

	} else {

		pr_debug("Not enough memory for image update:"

			 "size = %ld\n", size);

		rc = -ENOMEM;

	}

	return rc;

}

static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)

{

	int retval;

	size_t bytes_left;

	size_t data_length;

	char *ptempBuf = buffer;

	unsigned long imagesize;

	/* check to see if we have something to return */

	if (rbu_data.num_packets == 0) {

		pr_debug("read_packet_data: no packets written\n");

		retval = -ENOMEM;

		goto read_rbu_data_exit;

	}

	imagesize = rbu_data.num_packets * rbu_data.packetsize;

	if (pos > imagesize) {

		retval = 0;

		printk(KERN_WARNING "dell_rbu:read_packet_data: "

		       "data underrun\n");

		goto read_rbu_data_exit;

	}

	bytes_left = imagesize - pos;

	data_length = min(bytes_left, count);

	if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)

		goto read_rbu_data_exit;

	if ((pos + count) > imagesize) {

		rbu_data.packet_read_count = 0;

		/* this was the last copy */

		retval = bytes_left;

	} else

		retval = count;

      read_rbu_data_exit:

	return retval;

}

static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)

{

	unsigned char *ptemp = NULL;

	size_t bytes_left = 0;

	size_t data_length = 0;

	ssize_t ret_count = 0;

	/* check to see if we have something to return */

	if ((rbu_data.image_update_buffer == NULL) ||

	    (rbu_data.bios_image_size == 0)) {

		pr_debug("read_rbu_data_mono: image_update_buffer %p ,"

			 "bios_image_size %lu\n",

			 rbu_data.image_update_buffer,

			 rbu_data.bios_image_size);

		ret_count = -ENOMEM;

		goto read_rbu_data_exit;

	}

	if (pos > rbu_data.bios_image_size) {

		ret_count = 0;

		goto read_rbu_data_exit;

	}

	bytes_left = rbu_data.bios_image_size - pos;

	data_length = min(bytes_left, count);

	ptemp = rbu_data.image_update_buffer;

	memcpy(buffer, (ptemp + pos), data_length);

	if ((pos + count) > rbu_data.bios_image_size)

		/* this was the last copy */

		ret_count = bytes_left;

	else

		ret_count = count;

      read_rbu_data_exit:

	return ret_count;

}

static ssize_t

read_rbu_data(struct kobject *kobj, char *buffer, loff_t pos, size_t count)

{

	ssize_t ret_count = 0;

	spin_lock(&rbu_data.lock);

	if (!strcmp(image_type, "mono"))

		ret_count = read_rbu_mono_data(buffer, pos, count);

	else if (!strcmp(image_type, "packet"))

		ret_count = read_packet_data(buffer, pos, count);

	else

		pr_debug("read_rbu_data: invalid image type specified\n");

	spin_unlock(&rbu_data.lock);

	return ret_count;

}

static ssize_t

read_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,

		    size_t count)

{

	int size = 0;

	if (!pos)

		size = sprintf(buffer, "%s\n", image_type);

	return size;

}

static ssize_t

write_rbu_image_type(struct kobject *kobj, char *buffer, loff_t pos,

		     size_t count)

{

	int rc = count;

	spin_lock(&rbu_data.lock);

	if (strlen(buffer) < MAX_IMAGE_LENGTH)

		sscanf(buffer, "%s", image_type);

	else

		printk(KERN_WARNING "dell_rbu: image_type is invalid"

		       "max chars = %d, \n incoming str--%s-- \n",

		       MAX_IMAGE_LENGTH, buffer);

	/* we must free all previous allocations */

	packet_empty_list();

	img_update_free();

	spin_unlock(&rbu_data.lock);

	return rc;

}

static struct bin_attribute rbu_data_attr = {

	.attr = {.name = "data",.owner = THIS_MODULE,.mode = 0444},

	.read = read_rbu_data,

};

static struct bin_attribute rbu_image_type_attr = {

	.attr = {.name = "image_type",.owner = THIS_MODULE,.mode = 0644},

	.read = read_rbu_image_type,

	.write = write_rbu_image_type,

};

static void callbackfn_rbu(const struct firmware *fw, void *context)

{

	int rc = 0;

	if (!fw || !fw->size)

		return;

	spin_lock(&rbu_data.lock);

	if (!strcmp(image_type, "mono")) {

		if (!img_update_realloc(fw->size))

			memcpy(rbu_data.image_update_buffer,

			       fw->data, fw->size);

	} else if (!strcmp(image_type, "packet")) {

		if (!rbu_data.packetsize)

			rbu_data.packetsize = fw->size;

		else if (rbu_data.packetsize != fw->size) {

			packet_empty_list();

			rbu_data.packetsize = fw->size;

		}

		packetize_data(fw->data, fw->size);

	} else

		pr_debug("invalid image type specified.\n");

	spin_unlock(&rbu_data.lock);

	rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,

				     "dell_rbu", &rbu_device->dev,

				     &context, callbackfn_rbu);

	if (rc)

		printk(KERN_ERR

		       "dell_rbu:%s request_firmware_nowait failed"

		       " %d\n", __FUNCTION__, rc);

}

static int __init dcdrbu_init(void)

{

	int rc = 0;

	spin_lock_init(&rbu_data.lock);

	init_packet_head();

	rbu_device =

	    platform_device_register_simple("dell_rbu", -1, NULL, 0);

	if (!rbu_device) {

		printk(KERN_ERR

		       "dell_rbu:%s:platform_device_register_simple "

		       "failed\n", __FUNCTION__);

		return -EIO;

	}

	sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);

	sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);

	rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,

				     "dell_rbu", &rbu_device->dev,

				     &context, callbackfn_rbu);

	if (rc)

		printk(KERN_ERR "dell_rbu:%s:request_firmware_nowait"

		       " failed %d\n", __FUNCTION__, rc);

	return rc;

}

static __exit void dcdrbu_exit(void)

{

	spin_lock(&rbu_data.lock);

	packet_empty_list();

	img_update_free();

	spin_unlock(&rbu_data.lock);

	platform_device_unregister(rbu_device);

}

module_exit(dcdrbu_exit);

module_init(dcdrbu_init);