// SPDX-License-Identifier: GPL-2.0-only
/*
* dell_rbu.c
* Bios Update driver for Dell systems
* Author: Dell Inc
* Abhay Salunke <[email protected]>
*
* 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/admin-guide/dell_rbu.rst for more info.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.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>
#include <asm/set_memory.h>
MODULE_AUTHOR("Abhay Salunke <[email protected]>");
MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
MODULE_LICENSE("GPL");
MODULE_VERSION("3.2");
#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;
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 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("entry\n");
if (!rbu_data.packetsize) {
pr_debug("packetsize not specified\n");
retval = -EINVAL;
goto out_noalloc;
}
spin_unlock(&rbu_data.lock);
newpacket = kzalloc(sizeof (struct packet_data), GFP_KERNEL);
if (!newpacket) {
pr_warn("failed to allocate new packet\n");
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_t(unsigned int, allocation_floor / rbu_data.packetsize, 1);
invalid_addr_packet_array = kcalloc(packet_array_size, sizeof(void *),
GFP_KERNEL);
if (!invalid_addr_packet_array) {
pr_warn("failed to allocate invalid_addr_packet_array\n");
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) {
pr_warn("failed to allocate new packet\n");
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;
}
}
/*
* set to uncachable or it may never get written back before reboot
*/
set_memory_uc((unsigned long)packet_data_temp_buf, 1 << ordernum);
spin_lock(&rbu_data.lock);
newpacket->data = packet_data_temp_buf;
pr_debug("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("exit\n");
out_alloc_packet_array:
/* always free packet array */
while (idx--) {
pr_debug("freeing unused packet below floor 0x%lx\n",
(unsigned long)virt_to_phys(invalid_addr_packet_array[idx]));
free_pages((unsigned long)invalid_addr_packet_array[idx], 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(const u8 *data, size_t length)
{
int rc = 0;
int done = 0;
int packet_length;
u8 *temp;
u8 *end = (u8 *) data + length;
pr_debug("data length %zd\n", length);
if (!rbu_data.packetsize) {
pr_warn("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("%p:%td\n", temp, (end - temp));
temp += packet_length;
}
rbu_data.imagesize = length;
return rc;
}
static int do_packet_read(char *data, struct packet_data *newpacket,
int length, int bytes_read, int *list_read_count)
{
void *ptemp_buf;
int bytes_copied = 0;
int j = 0;
*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 packet_data *newpacket;
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;
list_for_each_entry(newpacket, (&packet_data_head.list)->next, list) {
bytes_copied = do_packet_read(pdest, newpacket,
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;
}
/*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 packet_data *newpacket, *tmp;
list_for_each_entry_safe(newpacket, tmp, (&packet_data_head.list)->next, list) {
list_del(&newpacket->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);
set_memory_wb((unsigned long)newpacket->data,
1 << newpacket->ordernum);
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);
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;
}
/*
* 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 img_buf_phys_addr;
int ordernum;
/*
* 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)) {
pr_err("corruption check failed\n");
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_DMA32, ordernum);
spin_lock(&rbu_data.lock);
if (!image_update_buffer) {
pr_debug("Not enough memory for image update: size = %ld\n", size);
return -ENOMEM;
}
img_buf_phys_addr = (unsigned long)virt_to_phys(image_update_buffer);
if (WARN_ON_ONCE(img_buf_phys_addr > BIOS_SCAN_LIMIT))
return -EINVAL; /* can't happen per definition */
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;
return 0;
}
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;
/* check to see if we have something to return */
if (rbu_data.num_packets == 0) {
pr_debug("no packets written\n");
retval = -ENOMEM;
goto read_rbu_data_exit;
}
if (pos > rbu_data.imagesize) {
retval = 0;
pr_warn("data underrun\n");
goto read_rbu_data_exit;
}
bytes_left = rbu_data.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) > rbu_data.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)
{
/* check to see if we have something to return */
if ((rbu_data.image_update_buffer == NULL) ||
(rbu_data.bios_image_size == 0)) {
pr_debug("image_update_buffer %p, bios_image_size %lu\n",
rbu_data.image_update_buffer,
rbu_data.bios_image_size);
return -ENOMEM;
}
return memory_read_from_buffer(buffer, count, &pos,
rbu_data.image_update_buffer, rbu_data.bios_image_size);
}
static ssize_t data_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
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("invalid image type specified\n");
spin_unlock(&rbu_data.lock);
return ret_count;
}
static BIN_ATTR_RO(data, 0);
static void callbackfn_rbu(const struct firmware *fw, void *context)
{
rbu_data.entry_created = 0;
if (!fw)
return;
if (!fw->size)
goto out;
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")) {
/*
* we need to free previous packets if a
* new hunk of packets needs to be downloaded
*/
packet_empty_list();
if (packetize_data(fw->data, fw->size))
/* Incase something goes wrong when we are
* in middle of packetizing the data, we
* need to free up whatever packets might
* have been created before we quit.
*/
packet_empty_list();
} else
pr_debug("invalid image type specified\n");
spin_unlock(&rbu_data.lock);
out:
release_firmware(fw);
}
static ssize_t image_type_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buffer, loff_t pos, size_t count)
{
int size = 0;
if (!pos)
size = scnprintf(buffer, count, "%s\n", image_type);
return size;
}
static ssize_t image_type_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buffer, loff_t pos, size_t count)
{
int rc = count;
int req_firm_rc = 0;
int i;
spin_lock(&rbu_data.lock);
/*
* Find the first newline or space
*/
for (i = 0; i < count; ++i)
if (buffer[i] == '\n' || buffer[i] == ' ') {
buffer[i] = '\0';
break;
}
if (i == count)
buffer[count] = '\0';
if (strstr(buffer, "mono"))
strcpy(image_type, "mono");
else if (strstr(buffer, "packet"))
strcpy(image_type, "packet");
else if (strstr(buffer, "init")) {
/*
* If due to the user error the driver gets in a bad
* state where even though it is loaded , the
* /sys/class/firmware/dell_rbu entries are missing.
* to cover this situation the user can recreate entries
* by writing init to image_type.
*/
if (!rbu_data.entry_created) {
spin_unlock(&rbu_data.lock);
req_firm_rc = request_firmware_nowait(THIS_MODULE,
FW_ACTION_NOUEVENT, "dell_rbu",
&rbu_device->dev, GFP_KERNEL, &context,
callbackfn_rbu);
if (req_firm_rc) {
pr_err("request_firmware_nowait failed %d\n", rc);
rc = -EIO;
} else
rbu_data.entry_created = 1;
spin_lock(&rbu_data.lock);
}
} else {
pr_warn("image_type is invalid\n");
spin_unlock(&rbu_data.lock);
return -EINVAL;
}
/* we must free all previous allocations */
packet_empty_list();
img_update_free();
spin_unlock(&rbu_data.lock);
return rc;
}
static BIN_ATTR_RW(image_type, 0);
static ssize_t packet_size_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buffer, loff_t pos, size_t count)
{
int size = 0;
if (!pos) {
spin_lock(&rbu_data.lock);
size = scnprintf(buffer, count, "%lu\n", rbu_data.packetsize);
spin_unlock(&rbu_data.lock);
}
return size;
}
static ssize_t packet_size_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buffer, loff_t pos, size_t count)
{
unsigned long temp;
spin_lock(&rbu_data.lock);
packet_empty_list();
sscanf(buffer, "%lu", &temp);
if (temp < 0xffffffff)
rbu_data.packetsize = temp;
spin_unlock(&rbu_data.lock);
return count;
}
static BIN_ATTR_RW(packet_size, 0);
static struct bin_attribute *rbu_bin_attrs[] = {
&bin_attr_data,
&bin_attr_image_type,
&bin_attr_packet_size,
NULL
};
static const struct attribute_group rbu_group = {
.bin_attrs = rbu_bin_attrs,
};
static int __init dcdrbu_init(void)
{
int rc;
spin_lock_init(&rbu_data.lock);
init_packet_head();
rbu_device = platform_device_register_simple("dell_rbu", PLATFORM_DEVID_NONE, NULL, 0);
if (IS_ERR(rbu_device)) {
pr_err("platform_device_register_simple failed\n");
return PTR_ERR(rbu_device);
}
rc = sysfs_create_group(&rbu_device->dev.kobj, &rbu_group);
if (rc)
goto out_devreg;
rbu_data.entry_created = 0;
return 0;
out_devreg:
platform_device_unregister(rbu_device);
return rc;
}
static __exit void dcdrbu_exit(void)
{
spin_lock(&rbu_data.lock);
packet_empty_list();
img_update_free();
spin_unlock(&rbu_data.lock);
sysfs_remove_group(&rbu_device->dev.kobj, &rbu_group);
platform_device_unregister(rbu_device);
}
module_exit(dcdrbu_exit);
module_init(dcdrbu_init);
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