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|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel Wireless WiMAX Connection 2400m
* Glue with the networking stack
*
* Copyright (C) 2007 Intel Corporation <linux-wimax@intel.com>
* Yanir Lubetkin <yanirx.lubetkin@intel.com>
* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
*
* This implements an ethernet device for the i2400m.
*
* We fake being an ethernet device to simplify the support from user
* space and from the other side. The world is (sadly) configured to
* take in only Ethernet devices...
*
* Because of this, when using firmwares <= v1.3, there is an
* copy-each-rxed-packet overhead on the RX path. Each IP packet has
* to be reallocated to add an ethernet header (as there is no space
* in what we get from the device). This is a known drawback and
* firmwares >= 1.4 add header space that can be used to insert the
* ethernet header without having to reallocate and copy.
*
* TX error handling is tricky; because we have to FIFO/queue the
* buffers for transmission (as the hardware likes it aggregated), we
* just give the skb to the TX subsystem and by the time it is
* transmitted, we have long forgotten about it. So we just don't care
* too much about it.
*
* Note that when the device is in idle mode with the basestation, we
* need to negotiate coming back up online. That involves negotiation
* and possible user space interaction. Thus, we defer to a workqueue
* to do all that. By default, we only queue a single packet and drop
* the rest, as potentially the time to go back from idle to normal is
* long.
*
* ROADMAP
*
* i2400m_open Called on ifconfig up
* i2400m_stop Called on ifconfig down
*
* i2400m_hard_start_xmit Called by the network stack to send a packet
* i2400m_net_wake_tx Wake up device from basestation-IDLE & TX
* i2400m_wake_tx_work
* i2400m_cmd_exit_idle
* i2400m_tx
* i2400m_net_tx TX a data frame
* i2400m_tx
*
* i2400m_change_mtu Called on ifconfig mtu XXX
*
* i2400m_tx_timeout Called when the device times out
*
* i2400m_net_rx Called by the RX code when a data frame is
* available (firmware <= 1.3)
* i2400m_net_erx Called by the RX code when a data frame is
* available (firmware >= 1.4).
* i2400m_netdev_setup Called to setup all the netdev stuff from
* alloc_netdev.
*/
#include <linux/if_arp.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/export.h>
#include "i2400m.h"
#define D_SUBMODULE netdev
#include "debug-levels.h"
enum {
/* netdev interface */
/* 20 secs? yep, this is the maximum timeout that the device
* might take to get out of IDLE / negotiate it with the base
* station. We add 1sec for good measure. */
I2400M_TX_TIMEOUT = 21 * HZ,
/*
* Experimentation has determined that, 20 to be a good value
* for minimizing the jitter in the throughput.
*/
I2400M_TX_QLEN = 20,
};
static
int i2400m_open(struct net_device *net_dev)
{
int result;
struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
struct device *dev = i2400m_dev(i2400m);
d_fnstart(3, dev, "(net_dev %p [i2400m %p])\n", net_dev, i2400m);
/* Make sure we wait until init is complete... */
mutex_lock(&i2400m->init_mutex);
if (i2400m->updown)
result = 0;
else
result = -EBUSY;
mutex_unlock(&i2400m->init_mutex);
d_fnend(3, dev, "(net_dev %p [i2400m %p]) = %d\n",
net_dev, i2400m, result);
return result;
}
static
int i2400m_stop(struct net_device *net_dev)
{
struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
struct device *dev = i2400m_dev(i2400m);
d_fnstart(3, dev, "(net_dev %p [i2400m %p])\n", net_dev, i2400m);
i2400m_net_wake_stop(i2400m);
d_fnend(3, dev, "(net_dev %p [i2400m %p]) = 0\n", net_dev, i2400m);
return 0;
}
/*
* Wake up the device and transmit a held SKB, then restart the net queue
*
* When the device goes into basestation-idle mode, we need to tell it
* to exit that mode; it will negotiate with the base station, user
* space may have to intervene to rehandshake crypto and then tell us
* when it is ready to transmit the packet we have "queued". Still we
* need to give it sometime after it reports being ok.
*
* On error, there is not much we can do. If the error was on TX, we
* still wake the queue up to see if the next packet will be luckier.
*
* If _cmd_exit_idle() fails...well, it could be many things; most
* commonly it is that something else took the device out of IDLE mode
* (for example, the base station). In that case we get an -EILSEQ and
* we are just going to ignore that one. If the device is back to
* connected, then fine -- if it is someother state, the packet will
* be dropped anyway.
*/
void i2400m_wake_tx_work(struct work_struct *ws)
{
int result;
struct i2400m *i2400m = container_of(ws, struct i2400m, wake_tx_ws);
struct net_device *net_dev = i2400m->wimax_dev.net_dev;
struct device *dev = i2400m_dev(i2400m);
struct sk_buff *skb;
unsigned long flags;
spin_lock_irqsave(&i2400m->tx_lock, flags);
skb = i2400m->wake_tx_skb;
i2400m->wake_tx_skb = NULL;
spin_unlock_irqrestore(&i2400m->tx_lock, flags);
d_fnstart(3, dev, "(ws %p i2400m %p skb %p)\n", ws, i2400m, skb);
result = -EINVAL;
if (skb == NULL) {
dev_err(dev, "WAKE&TX: skb disappeared!\n");
goto out_put;
}
/* If we have, somehow, lost the connection after this was
* queued, don't do anything; this might be the device got
* reset or just disconnected. */
if (unlikely(!netif_carrier_ok(net_dev)))
goto out_kfree;
result = i2400m_cmd_exit_idle(i2400m);
if (result == -EILSEQ)
result = 0;
if (result < 0) {
dev_err(dev, "WAKE&TX: device didn't get out of idle: "
"%d - resetting\n", result);
i2400m_reset(i2400m, I2400M_RT_BUS);
goto error;
}
result = wait_event_timeout(i2400m->state_wq,
i2400m->state != I2400M_SS_IDLE,
net_dev->watchdog_timeo - HZ/2);
if (result == 0)
result = -ETIMEDOUT;
if (result < 0) {
dev_err(dev, "WAKE&TX: error waiting for device to exit IDLE: "
"%d - resetting\n", result);
i2400m_reset(i2400m, I2400M_RT_BUS);
goto error;
}
msleep(20); /* device still needs some time or it drops it */
result = i2400m_tx(i2400m, skb->data, skb->len, I2400M_PT_DATA);
error:
netif_wake_queue(net_dev);
out_kfree:
kfree_skb(skb); /* refcount transferred by _hard_start_xmit() */
out_put:
i2400m_put(i2400m);
d_fnend(3, dev, "(ws %p i2400m %p skb %p) = void [%d]\n",
ws, i2400m, skb, result);
}
/*
* Prepare the data payload TX header
*
* The i2400m expects a 4 byte header in front of a data packet.
*
* Because we pretend to be an ethernet device, this packet comes with
* an ethernet header. Pull it and push our header.
*/
static
void i2400m_tx_prep_header(struct sk_buff *skb)
{
struct i2400m_pl_data_hdr *pl_hdr;
skb_pull(skb, ETH_HLEN);
pl_hdr = skb_push(skb, sizeof(*pl_hdr));
pl_hdr->reserved = 0;
}
/*
* Cleanup resources acquired during i2400m_net_wake_tx()
*
* This is called by __i2400m_dev_stop and means we have to make sure
* the workqueue is flushed from any pending work.
*/
void i2400m_net_wake_stop(struct i2400m *i2400m)
{
struct device *dev = i2400m_dev(i2400m);
struct sk_buff *wake_tx_skb;
unsigned long flags;
d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
/*
* See i2400m_hard_start_xmit(), references are taken there and
* here we release them if the packet was still pending.
*/
cancel_work_sync(&i2400m->wake_tx_ws);
spin_lock_irqsave(&i2400m->tx_lock, flags);
wake_tx_skb = i2400m->wake_tx_skb;
i2400m->wake_tx_skb = NULL;
spin_unlock_irqrestore(&i2400m->tx_lock, flags);
if (wake_tx_skb) {
i2400m_put(i2400m);
kfree_skb(wake_tx_skb);
}
d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
}
/*
* TX an skb to an idle device
*
* When the device is in basestation-idle mode, we need to wake it up
* and then TX. So we queue a work_struct for doing so.
*
* We need to get an extra ref for the skb (so it is not dropped), as
* well as be careful not to queue more than one request (won't help
* at all). If more than one request comes or there are errors, we
* just drop the packets (see i2400m_hard_start_xmit()).
*/
static
int i2400m_net_wake_tx(struct i2400m *i2400m, struct net_device *net_dev,
struct sk_buff *skb)
{
int result;
struct device *dev = i2400m_dev(i2400m);
unsigned long flags;
d_fnstart(3, dev, "(skb %p net_dev %p)\n", skb, net_dev);
if (net_ratelimit()) {
d_printf(3, dev, "WAKE&NETTX: "
"skb %p sending %d bytes to radio\n",
skb, skb->len);
d_dump(4, dev, skb->data, skb->len);
}
/* We hold a ref count for i2400m and skb, so when
* stopping() the device, we need to cancel that work
* and if pending, release those resources. */
result = 0;
spin_lock_irqsave(
|