[PATCH] USB: usbnet (1/9) clean up framing

This starts to prepare the core of "usbnet" to know less about various
framing protocols that map Ethernet packets onto USB, so "minidrivers"
can be modules that just plug into the core.

  - Remove some framing-specific code that cluttered the core:

      * net->hard_header_len records how much space to preallocate;
        now drivers that add their own framing (Net1080, GeneLink,
	Zaurus, and RNDIS) will have smoother TX paths.  Even for
	the drivers (Zaurus, Net1080) that need trailers.

      * defines new dev->hard_mtu, using this "hardware" limit to
        check changes to the link's settable "software" mtu.

      * now net->hard_header_len and dev->hard_mtu are set up in the
        driver bind() routines, if needed.

  - Transaction ID is no longer specific to the Net1080 framing;
    RNDIS needs one too.

  - Creates a new "usbnet.h" header with declarations that are shared
    between the core and what will be separate modules.

  - Plus a couple other minor tweaks, like recognizing -ESHUTDOWN
    means the keventd work should just shut itself down asap.

The core code is only about 1/3 of this large file.  Splitting out the
minidrivers into separate modules (e.g. ones for ASIX adapters,
Zaurii and similar, CDC Ethernet, etc), in later patches, will
improve maintainability and shrink typical runtime footprints.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 89 insertions, 200 deletions

diff --git a/drivers/usb/net/usbnet.c b/drivers/usb/net/usbnet.c
index 3c6eef4168e5..3f2cad6dc261 100644
--- a/drivers/usb/net/usbnet.c
+++ b/drivers/usb/net/usbnet.c
@@ -1,6 +1,6 @@
 /*
  * USB Networking Links
- * Copyright (C) 2000-2005 by David Brownell <dbrownell@users.sourceforge.net>
+ * Copyright (C) 2000-2005 by David Brownell
  * Copyright (C) 2002 Pavel Machek <pavel@ucw.cz>
  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
  * Copyright (C) 2005 Phil Chang <pchang23@sbcglobal.net>
@@ -126,19 +126,18 @@
 #include <linux/init.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
-#include <linux/random.h>
 #include <linux/ethtool.h>
 #include <linux/workqueue.h>
 #include <linux/mii.h>
-#include <asm/uaccess.h>
-#include <asm/unaligned.h>
 #include <linux/usb.h>
-#include <asm/io.h>
-#include <asm/scatterlist.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 
-#define DRIVER_VERSION          "03-Nov-2004"
+#include <asm/unaligned.h>
+
+#include "usbnet.h"
+
+#define DRIVER_VERSION          "22-Aug-2005"
 
 
 /*-------------------------------------------------------------------------*/
@@ -149,14 +148,16 @@
  * One maximum size Ethernet packet takes twenty four of them.
  * For high speed, each frame comfortably fits almost 36 max size
  * Ethernet packets (so queues should be bigger).
+ *
+ * REVISIT qlens should be members of 'struct usbnet'; the goal is to
+ * let the USB host controller be busy for 5msec or more before an irq
+ * is required, under load.  Jumbograms change the equation.
  */
 #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)
 #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)
 
-// packets are always ethernet inside
-// ... except they can be bigger (limit of 64K with NetChip framing)
+/* packets are always ethernet, sometimes wrapped in other framing */
 #define MIN_PACKET      sizeof(struct ethhdr)
-#define MAX_PACKET      32768
 
 // reawaken network queue this soon after stopping; else watchdog barks
 #define TX_TIMEOUT_JIFFIES      (5*HZ)
@@ -166,7 +167,7 @@
 #define THROTTLE_JIFFIES        (HZ/8)
 
 // for vendor-specific control operations
-#define CONTROL_TIMEOUT_MS      500
+#define CONTROL_TIMEOUT_MS      USB_CTRL_GET_TIMEOUT
 
 // between wakeups
 #define UNLINK_TIMEOUT_MS       3
@@ -176,109 +177,6 @@
 // randomly generated ethernet address
 static u8       node_id [ETH_ALEN];
 
-// state we keep for each device we handle
-struct usbnet {
-        // housekeeping
-        struct usb_device       *udev;
-        struct driver_info      *driver_info;
-        wait_queue_head_t       *wait;
-
-        // i/o info: pipes etc
-        unsigned                in, out;
-        struct usb_host_endpoint *status;
-        unsigned                maxpacket;
-        struct timer_list       delay;
-
-        // protocol/interface state
-        struct net_device       *net;
-        struct net_device_stats stats;
-        int                     msg_enable;
-        unsigned long           data [5];
-
-        struct mii_if_info      mii;
-
-        // various kinds of pending driver work
-        struct sk_buff_head     rxq;
-        struct sk_buff_head     txq;
-        struct sk_buff_head     done;
-        struct urb              *interrupt;
-        struct tasklet_struct   bh;
-
-        struct work_struct      kevent;
-        unsigned long           flags;
-#               define EVENT_TX_HALT    0
-#               define EVENT_RX_HALT    1
-#               define EVENT_RX_MEMORY  2
-#               define EVENT_STS_SPLIT  3
-#               define EVENT_LINK_RESET 4
-};
-
-// device-specific info used by the driver
-struct driver_info {
-        char            *description;
-
-        int             flags;
-/* framing is CDC Ethernet, not writing ZLPs (hw issues), or optionally: */
-#define FLAG_FRAMING_NC 0x0001          /* guard against device dropouts */ 
-#define FLAG_FRAMING_GL 0x0002          /* genelink batches packets */
-#define FLAG_FRAMING_Z  0x0004          /* zaurus adds a trailer */
-#define FLAG_FRAMING_RN 0x0008          /* RNDIS batches, plus huge header */
-
-#define FLAG_NO_SETINT  0x0010          /* device can't set_interface() */
-#define FLAG_ETHER      0x0020          /* maybe use "eth%d" names */
-
-#define FLAG_FRAMING_AX 0x0040          /* AX88772/178 packets */
-
-        /* init device ... can sleep, or cause probe() failure */
-        int     (*bind)(struct usbnet *, struct usb_interface *);
-
-        /* cleanup device ... can sleep, but can't fail */
-        void    (*unbind)(struct usbnet *, struct usb_interface *);
-
-        /* reset device ... can sleep */
-        int     (*reset)(struct usbnet *);
-
-        /* see if peer is connected ... can sleep */
-        int     (*check_connect)(struct usbnet *);
-
-        /* for status polling */
-        void    (*status)(struct usbnet *, struct urb *);
-
-        /* link reset handling, called from defer_kevent */
-        int     (*link_reset)(struct usbnet *);
-
-        /* fixup rx packet (strip framing) */
-        int     (*rx_fixup)(struct usbnet *dev, struct sk_buff *skb);
-
-        /* fixup tx packet (add framing) */
-        struct sk_buff  *(*tx_fixup)(struct usbnet *dev,
-                                struct sk_buff *skb, unsigned flags);
-
-        // FIXME -- also an interrupt mechanism
-        // useful for at least PL2301/2302 and GL620USB-A
-        // and CDC use them to report 'is it connected' changes
-
-        /* for new devices, use the descriptor-reading code instead */
-        int             in;             /* rx endpoint */
-        int             out;            /* tx endpoint */
-
-        unsigned long   data;           /* Misc driver specific data */
-};
-
-// we record the state for each of our queued skbs
-enum skb_state {
-        illegal = 0,
-        tx_start, tx_done,
-        rx_start, rx_done, rx_cleanup
-};
-
-struct skb_data {       // skb->cb is one of these
-        struct urb              *urb;
-        struct usbnet           *dev;
-        enum skb_state          state;
-        size_t                  length;
-};
-
 static const char driver_name [] = "usbnet";
 
 /* use ethtool to change the level for any given device */
@@ -286,22 +184,6 @@ static int msg_level = -1;
 module_param (msg_level, int, 0);
 MODULE_PARM_DESC (msg_level, "Override default message level");
 
-
-#ifdef DEBUG
-#define devdbg(usbnet, fmt, arg...) \
-        printk(KERN_DEBUG "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
-#else
-#define devdbg(usbnet, fmt, arg...) do {} while(0)
-#endif
-
-#define deverr(usbnet, fmt, arg...) \
-        printk(KERN_ERR "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
-#define devwarn(usbnet, fmt, arg...) \
-        printk(KERN_WARNING "%s: " fmt "\n" , (usbnet)->net->name , ## arg)
-
-#define devinfo(usbnet, fmt, arg...) \
-        printk(KERN_INFO "%s: " fmt "\n" , (usbnet)->net->name , ## arg); \
-
 /*-------------------------------------------------------------------------*/
 
 static void usbnet_get_drvinfo (struct net_device *, struct ethtool_drvinfo *);
@@ -921,6 +803,11 @@ static int ax8817x_bind(struct usbnet *dev, struct usb_interface *intf)
                 ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_PAUSE_CAP);
         mii_nway_restart(&dev->mii);
 
+        if (dev->driver_info->flags & FLAG_FRAMING_AX) {
+                /* REVISIT:  adjust hard_header_len too */
+                dev->hard_mtu = 2048;
+        }
+
         return 0;
 out2:
         kfree(buf);
@@ -1432,9 +1319,8 @@ static int generic_cdc_bind (struct usbnet *dev, struct usb_interface *intf)
                                         info->ether->bLength);
                                 goto bad_desc;
                         }
-                        dev->net->mtu = le16_to_cpup (
-                                                &info->ether->wMaxSegmentSize)
-                                        - ETH_HLEN;
+                        dev->hard_mtu = le16_to_cpu(
+                                                info->ether->wMaxSegmentSize);
                         /* because of Zaurus, we may be ignoring the host
                          * side link address we were given.
                          */
@@ -1988,9 +1874,17 @@ genelink_tx_fixup (struct usbnet *dev, struct sk_buff *skb, unsigned flags)
         return skb;
 }
 
+static int genelink_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+        dev->hard_mtu = GL_RCV_BUF_SIZE;
+        dev->net->hard_header_len += 4;
+        return 0;
+}
+
 static const struct driver_info genelink_info = {
         .description =  "Genesys GeneLink",
         .flags =        FLAG_FRAMING_GL | FLAG_NO_SETINT,
+        .bind =         genelink_bind,
         .rx_fixup =     genelink_rx_fixup,
         .tx_fixup =     genelink_tx_fixup,
 
@@ -2015,7 +1909,6 @@ static const struct driver_info	genelink_info = {
  *
  *-------------------------------------------------------------------------*/
 
-#define dev_packet_id   data[0]
 #define frame_errors    data[1]
 
 /*
@@ -2057,6 +1950,9 @@ struct nc_trailer {
 
 #define MIN_FRAMED      FRAMED_SIZE(0)
 
+/* packets _could_ be up to 64KB... */
+#define NC_MAX_PACKET   32767
+
 
 /*
  * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
@@ -2398,16 +2294,14 @@ static void nc_ensure_sync (struct usbnet *dev)
 static int net1080_rx_fixup (struct usbnet *dev, struct sk_buff *skb)
 {
         struct nc_header        *header;
+        struct net_device       *net = dev->net;
         struct nc_trailer       *trailer;
         u16                     hdr_len, packet_len;
 
-        if (!(skb->len & 0x01)
-                        || MIN_FRAMED > skb->len
-                        || skb->len > FRAMED_SIZE (dev->net->mtu)) {
+        if (!(skb->len & 0x01)) {
                 dev->stats.rx_frame_errors++;
                 dbg ("rx framesize %d range %d..%d mtu %d", skb->len,
-                        (int)MIN_FRAMED, (int)FRAMED_SIZE (dev->net->mtu),
-                        dev->net->mtu);
+                        net->hard_header_len, dev->hard_mtu, net->mtu);
                 nc_ensure_sync (dev);
                 return 0;
         }
@@ -2415,7 +2309,7 @@ static int net1080_rx_fixup (struct usbnet *dev, struct sk_buff *skb)
         header = (struct nc_header *) skb->data;
         hdr_len = le16_to_cpup (&header->hdr_len);
         packet_len = le16_to_cpup (&header->packet_len);
-        if (FRAMED_SIZE (packet_len) > MAX_PACKET) {
+        if (FRAMED_SIZE (packet_len) > NC_MAX_PACKET) {
                 dev->stats.rx_frame_errors++;
                 dbg ("packet too big, %d", packet_len);
                 nc_ensure_sync (dev);
@@ -2505,11 +2399,23 @@ net1080_tx_fixup (struct usbnet *dev, struct sk_buff *skb, unsigned flags)
         return skb2;
 }
 
+static int net1080_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+        unsigned        extra = sizeof (struct nc_header)
+                                + 1
+                                + sizeof (struct nc_trailer);
+
+        dev->net->hard_header_len += extra;
+        dev->hard_mtu = NC_MAX_PACKET;
+        return 0;
+}
+
 static const struct driver_info net1080_info = {
         .description =  "NetChip TurboCONNECT",
         .flags =        FLAG_FRAMING_NC,
+        .bind =         net1080_bind,
         .reset =        net1080_reset,
-        .check_connect =net1080_check_connect,
+        .check_connect = net1080_check_connect,
         .rx_fixup =     net1080_rx_fixup,
         .tx_fixup =     net1080_tx_fixup,
 };
@@ -2690,11 +2596,20 @@ done:
         return skb;
 }
 
+static int zaurus_bind (struct usbnet *dev, struct usb_interface *intf)
+{
+        /* Belcarra's funky framing has other options; mostly
+         * TRAILERS (!) with 4 bytes CRC, and maybe 2 pad bytes.
+         */
+        dev->net->hard_header_len += 6;
+        return generic_cdc_bind(dev, intf);
+}
+
 static const struct driver_info zaurus_sl5x00_info = {
         .description =  "Sharp Zaurus SL-5x00",
         .flags =        FLAG_FRAMING_Z,
         .check_connect = always_connected,
-        .bind =         generic_cdc_bind,
+        .bind =         zaurus_bind,
         .unbind =       cdc_unbind,
         .tx_fixup =     zaurus_tx_fixup,
 };
@@ -2704,7 +2619,7 @@ static const struct driver_info	zaurus_pxa_info = {
         .description =  "Sharp Zaurus, PXA-2xx based",
         .flags =        FLAG_FRAMING_Z,
         .check_connect = always_connected,
-        .bind =         generic_cdc_bind,
+        .bind =         zaurus_bind,
         .unbind =       cdc_unbind,
         .tx_fixup =     zaurus_tx_fixup,
 };
@@ -2714,7 +2629,7 @@ static const struct driver_info	olympus_mxl_info = {
         .description =  "Olympus R1000",
         .flags =        FLAG_FRAMING_Z,
         .check_connect = always_connected,
-        .bind =         generic_cdc_bind,
+        .bind =         zaurus_bind,
         .unbind =       cdc_unbind,
         .tx_fixup =     zaurus_tx_fixup,
 };
@@ -2868,22 +2783,12 @@ static const struct driver_info	bogus_mdlm_info = {
 static int usbnet_change_mtu (struct net_device *net, int new_mtu)
 {
         struct usbnet   *dev = netdev_priv(net);
+        int             ll_mtu = new_mtu + net->hard_header_len;
 
-        if (new_mtu <= MIN_PACKET || new_mtu > MAX_PACKET)
-                return -EINVAL;
-#ifdef  CONFIG_USB_NET1080
-        if (((dev->driver_info->flags) & FLAG_FRAMING_NC)) {
-                if (FRAMED_SIZE (new_mtu) > MAX_PACKET)
-                        return -EINVAL;
-        }
-#endif
-#ifdef  CONFIG_USB_GENESYS
-        if (((dev->driver_info->flags) & FLAG_FRAMING_GL)
-                        && new_mtu > GL_MAX_PACKET_LEN)
+        if (new_mtu <= 0 || ll_mtu > dev->hard_mtu)
                 return -EINVAL;
-#endif
         // no second zero-length packet read wanted after mtu-sized packets
-        if (((new_mtu + sizeof (struct ethhdr)) % dev->maxpacket) == 0)
+        if ((ll_mtu % dev->maxpacket) == 0)
                 return -EDOM;
         net->mtu = new_mtu;
         return 0;
@@ -2943,33 +2848,8 @@ static void rx_submit (struct usbnet *dev, struct urb *urb, unsigned flags)
         unsigned long           lockflags;
         size_t                  size;
 
-#ifdef CONFIG_USB_NET1080
-        if (dev->driver_info->flags & FLAG_FRAMING_NC)
-                size = FRAMED_SIZE (dev->net->mtu);
-        else
-#endif
-#ifdef CONFIG_USB_GENESYS
-        if (dev->driver_info->flags & FLAG_FRAMING_GL)
-                size = GL_RCV_BUF_SIZE;
-        else
-#endif
-#ifdef CONFIG_USB_ZAURUS
-        if (dev->driver_info->flags & FLAG_FRAMING_Z)
-                size = 6 + (sizeof (struct ethhdr) + dev->net->mtu);
-        else
-#endif
-#ifdef CONFIG_USB_RNDIS
-        if (dev->driver_info->flags & FLAG_FRAMING_RN)
-                size = RNDIS_MAX_TRANSFER;
-        else
-#endif
-#ifdef CONFIG_USB_AX8817X
-        if (dev->driver_info->flags & FLAG_FRAMING_AX)
-                size = 2048;
-        else
-#endif
-                size = (sizeof (struct ethhdr) + dev->net->mtu);
-
+        size = max(dev->net->hard_header_len + dev->net->mtu,
+                        (unsigned)ETH_FRAME_LEN);
         if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
                 if (netif_msg_rx_err (dev))
                         devdbg (dev, "no rx skb");
@@ -3062,7 +2942,7 @@ static void rx_complete (struct urb *urb, struct pt_regs *regs)
         switch (urb_status) {
             // success
             case 0:
-                if (MIN_PACKET > skb->len || skb->len > MAX_PACKET) {
+                if (skb->len < dev->net->hard_header_len) {
                         entry->state = rx_cleanup;
                         dev->stats.rx_errors++;
                         dev->stats.rx_length_errors++;
@@ -3334,11 +3214,11 @@ static u32 usbnet_get_link (struct net_device *net)
 {
         struct usbnet *dev = netdev_priv(net);
 
-        /* If a check_connect is defined, return it's results */
+        /* If a check_connect is defined, return its result */
         if (dev->driver_info->check_connect)
                 return dev->driver_info->check_connect (dev) == 0;
 
-        /* Otherwise, we're up to avoid breaking scripts */
+        /* Otherwise, say we're up (to avoid breaking scripts) */
         return 1;
 }
 
@@ -3386,19 +3266,24 @@ kevent (void *data)
         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
                 unlink_urbs (dev, &dev->txq);
                 status = usb_clear_halt (dev->udev, dev->out);
-                if (status < 0 && status != -EPIPE) {
+                if (status < 0
+                                && status != -EPIPE
+                                && status != -ESHUTDOWN) {
                         if (netif_msg_tx_err (dev))
                                 deverr (dev, "can't clear tx halt, status %d",
                                         status);
                 } else {
                         clear_bit (EVENT_TX_HALT, &dev->flags);
-                        netif_wake_queue (dev->net);
+                        if (status != -ESHUTDOWN)
+                                netif_wake_queue (dev->net);
                 }
         }
         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
                 unlink_urbs (dev, &dev->rxq);
                 status = usb_clear_halt (dev->udev, dev->in);
-                if (status < 0 && status != -EPIPE) {
+                if (status < 0
+                                && status != -EPIPE
+                                && status != -ESHUTDOWN) {
                         if (netif_msg_rx_err (dev))
                                 deverr (dev, "can't clear rx halt, status %d",
                                         status);
@@ -3574,7 +3459,7 @@ static int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
 
 #ifdef  CONFIG_USB_NET1080
         if (info->flags & FLAG_FRAMING_NC) {
-                header->packet_id = cpu_to_le16 ((u16)dev->dev_packet_id++);
+                header->packet_id = cpu_to_le16 ((u16)dev->xid++);
                 put_unaligned (header->packet_id, &trailer->packet_id);
 #if 0
                 devdbg (dev, "frame >tx h %d p %d id %d",
@@ -3776,6 +3661,7 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
         dev->net = net;
         strcpy (net->name, "usb%d");
         memcpy (net->dev_addr, node_id, sizeof node_id);
+        dev->hard_mtu = net->mtu + net->hard_header_len;
 
 #if 0
 // dma_supported() is deeply broken on almost all architectures
@@ -3804,6 +3690,10 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
                 if ((dev->driver_info->flags & FLAG_ETHER) != 0
                                 && (net->dev_addr [0] & 0x02) == 0)
                         strcpy (net->name, "eth%d");
+
+                /* maybe the remote can't receive an Ethernet MTU */
+                if (net->mtu > (dev->hard_mtu - net->hard_header_len))
+                        net->mtu = dev->hard_mtu - net->hard_header_len;
         } else if (!info->in || info->out)
                 status = get_endpoints (dev, udev);
         else {
@@ -3817,7 +3707,6 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
                         status = 0;
 
         }
-
         if (status == 0 && dev->status)
                 status = init_status (dev, udev);
         if (status < 0)
@@ -4212,7 +4101,7 @@ static struct ethtool_ops usbnet_ethtool_ops = {
 
 /*-------------------------------------------------------------------------*/
 
-static int __init usbnet_init (void)
+static int __init usbnet_init(void)
 {
         // compiler should optimize these out
         BUG_ON (sizeof (((struct sk_buff *)0)->cb)
@@ -4226,14 +4115,14 @@ static int __init usbnet_init (void)
 
         return usb_register(&usbnet_driver);
 }
-module_init (usbnet_init);
+module_init(usbnet_init);
 
-static void __exit usbnet_exit (void)
+static void __exit usbnet_exit(void)
 {
-        usb_deregister (&usbnet_driver);
+        usb_deregister(&usbnet_driver);
 }
-module_exit (usbnet_exit);
+module_exit(usbnet_exit);
 
-MODULE_AUTHOR ("David Brownell <dbrownell@users.sourceforge.net>");
-MODULE_DESCRIPTION ("USB Host-to-Host Link Drivers (numerous vendors)");
-MODULE_LICENSE ("GPL");
+MODULE_AUTHOR("David Brownell");
+MODULE_DESCRIPTION("USB Host-to-Host Link Drivers (numerous vendors)");
+MODULE_LICENSE("GPL");