[PATCH] dell_rbu: changes in packet update mechanism

In the current dell_rbu code ver 2.0 the packet update mechanism makes the
user app dump every individual packet in to the driver.

This adds in efficiency as every packet update makes the
/sys/class/firmware/dell_rbu/loading and data files to disappear and reappear
again.  Thus the user app needs to wait for the files to reappear to dump
another packet.  This slows down the packet update tremendously in case of
large number of packets.  I am submitting a new patch for dell_rbu which will
change the way we do packet updates;

In the new method the user app will create a new single file which has already
packetized the rbu image and all the packets are now staged in this file.

This driver also creates a new entry in
/sys/devices/platform/dell_rbu/packet_size ; the user needs to echo the packet
size here before downloading the packet file.

The user should do the following:

 create one single file which has all the packets stacked together.
 echo the packet size in to /sys/devices/platform/dell_rbu/packet_size.
 echo 1 > /sys/class/firmware/dell_rbu/loading
 cat the packetfile > /sys/class/firmware/dell_rbu/data
 echo 0 > /sys/class/firmware/dell_rbu/loading

The driver takes the file which came through /sys/class/firmware/dell_rbu/data
and takes chunks of paket_size data from it and place in contiguous memory.

This makes packet update process very efficient and fast.  As all the packet
update happens in one single operation.  The user can still read back the
downloaded file from /sys/devices/platform/dell_rbu/data.

Signed-off-by: Abhay Salunke <abhay_salunke@dell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 93 insertions, 81 deletions

diff --git a/drivers/firmware/dell_rbu.c b/drivers/firmware/dell_rbu.c
index b66782398258..4f4ba9b6d182 100644
--- a/drivers/firmware/dell_rbu.c
+++ b/drivers/firmware/dell_rbu.c
@@ -50,7 +50,7 @@
 MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
 MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
 MODULE_LICENSE("GPL");
-MODULE_VERSION("2.0");
+MODULE_VERSION("3.0");
 
 #define BIOS_SCAN_LIMIT 0xffffffff
 #define MAX_IMAGE_LENGTH 16
@@ -62,15 +62,16 @@ static struct _rbu_data {
         int dma_alloc;
         spinlock_t lock;
         unsigned long packet_read_count;
-        unsigned long packet_write_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");
+MODULE_PARM_DESC(image_type,
+        "BIOS image type. choose- mono or packet or init");
 
 struct packet_data {
         struct list_head list;
@@ -88,55 +89,13 @@ 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;
+        rbu_data.imagesize = 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)
+static int create_packet(void *data, size_t length)
 {
         struct packet_data *newpacket;
         int ordernum = 0;
@@ -186,9 +145,11 @@ static int create_packet(size_t length)
         INIT_LIST_HEAD(&newpacket->list);
         list_add_tail(&newpacket->list, &packet_data_head.list);
         /*
-         * packets have fixed size
+         * packets may not have fixed size
          */
-        newpacket->length = rbu_data.packetsize;
+        newpacket->length = length;
+
+        memcpy(newpacket->data, data, length);
 
         pr_debug("create_packet: exit \n");
 
@@ -198,13 +159,37 @@ static int create_packet(size_t length)
 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;
+        }
 
-        if (!rbu_data.packet_write_count) {
-                if ((rc = create_packet(length)))
+        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;
         }
-        if ((rc = fill_last_packet(data, length)))
-                return rc;
+
+        rbu_data.imagesize = length;
 
         return rc;
 }
@@ -243,7 +228,7 @@ static int do_packet_read(char *data, struct list_head *ptemp_list,
         return bytes_copied;
 }
 
-static int packet_read_list(char *data, size_t *pread_length)
+static int packet_read_list(char *data, size_t * pread_length)
 {
         struct list_head *ptemp_list;
         int temp_count = 0;
@@ -303,10 +288,9 @@ static void packet_empty_list(void)
                         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;
+        rbu_data.imagesize = 0;
 }
 
 /*
@@ -425,7 +409,6 @@ static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
         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) {
@@ -434,22 +417,20 @@ static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
                 goto read_rbu_data_exit;
         }
 
-        imagesize = rbu_data.num_packets * rbu_data.packetsize;
-
-        if (pos > imagesize) {
+        if (pos > rbu_data.imagesize) {
                 retval = 0;
                 printk(KERN_WARNING "dell_rbu:read_packet_data: "
                         "data underrun\n");
                 goto read_rbu_data_exit;
         }
 
-        bytes_left = imagesize - pos;
+        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) > imagesize) {
+        if ((pos + count) > rbu_data.imagesize) {
                 rbu_data.packet_read_count = 0;
                 /* this was the last copy */
                 retval = bytes_left;
@@ -499,7 +480,7 @@ static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 }
 
 static ssize_t read_rbu_data(struct kobject *kobj, char *buffer,
-                        loff_t pos, size_t count)
+        loff_t pos, size_t count)
 {
         ssize_t ret_count = 0;
 
@@ -531,13 +512,18 @@ static void callbackfn_rbu(const struct firmware *fw, void *context)
                         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) {
+                /*
+                 * 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();
-                        rbu_data.packetsize = fw->size;
-                }
-                packetize_data(fw->data, fw->size);
         } else
                 pr_debug("invalid image type specified.\n");
         spin_unlock(&rbu_data.lock);
@@ -553,7 +539,7 @@ static void callbackfn_rbu(const struct firmware *fw, void *context)
 }
 
 static ssize_t read_rbu_image_type(struct kobject *kobj, char *buffer,
-                        loff_t pos, size_t count)
+        loff_t pos, size_t count)
 {
         int size = 0;
         if (!pos)
@@ -562,7 +548,7 @@ static ssize_t read_rbu_image_type(struct kobject *kobj, char *buffer,
 }
 
 static ssize_t write_rbu_image_type(struct kobject *kobj, char *buffer,
-                        loff_t pos, size_t count)
+        loff_t pos, size_t count)
 {
         int rc = count;
         int req_firm_rc = 0;
@@ -621,25 +607,49 @@ static ssize_t write_rbu_image_type(struct kobject *kobj, char *buffer,
         return rc;
 }
 
+static ssize_t read_rbu_packet_size(struct kobject *kobj, char *buffer,
+        loff_t pos, size_t count)
+{
+        int size = 0;
+        if (!pos) {
+                spin_lock(&rbu_data.lock);
+                size = sprintf(buffer, "%lu\n", rbu_data.packetsize);
+                spin_unlock(&rbu_data.lock);
+        }
+        return size;
+}
+
+static ssize_t write_rbu_packet_size(struct kobject *kobj, 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 struct bin_attribute rbu_data_attr = {
-        .attr = {
-                .name = "data",
-                .owner = THIS_MODULE,
-                .mode = 0444,
-        },
+        .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,
-        },
+        .attr = {.name = "image_type",.owner = THIS_MODULE,.mode = 0644},
         .read = read_rbu_image_type,
         .write = write_rbu_image_type,
 };
 
+static struct bin_attribute rbu_packet_size_attr = {
+        .attr = {.name = "packet_size",.owner = THIS_MODULE,.mode = 0644},
+        .read = read_rbu_packet_size,
+        .write = write_rbu_packet_size,
+};
+
 static int __init dcdrbu_init(void)
 {
         int rc = 0;
@@ -657,6 +667,8 @@ static int __init dcdrbu_init(void)
 
         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
         sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
+        sysfs_create_bin_file(&rbu_device->dev.kobj,
+                &rbu_packet_size_attr);
 
         rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG,
                 "dell_rbu", &rbu_device->dev, &context, callbackfn_rbu);