--- /dev/null
+/*
+ * 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);