/*
 *	Spanning tree protocol; BPDU handling
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/netfilter_bridge.h>
#include <linux/etherdevice.h>
#include <linux/llc.h>
#include <linux/slab.h>
#include <linux/pkt_sched.h>
#include <net/net_namespace.h>
#include <net/llc.h>
#include <net/llc_pdu.h>
#include <net/stp.h>
#include <asm/unaligned.h>

#include "br_private.h"
#include "br_private_stp.h"

#define STP_HZ		256

#define LLC_RESERVE sizeof(struct llc_pdu_un)

static int br_send_bpdu_finish(struct net *net, struct sock *sk,
			       struct sk_buff *skb)
{
	return dev_queue_xmit(skb);
}

static void br_send_bpdu(struct net_bridge_port *p,
			 const unsigned char *data, int length)
{
	struct sk_buff *skb;

	skb = dev_alloc_skb(length+LLC_RESERVE);
	if (!skb)
		return;

	skb->dev = p->dev;
	skb->protocol = htons(ETH_P_802_2);
	skb->priority = TC_PRIO_CONTROL;

	skb_reserve(skb, LLC_RESERVE);
	memcpy(__skb_put(skb, length), data, length);

	llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
			    LLC_SAP_BSPAN, LLC_PDU_CMD);
	llc_pdu_init_as_ui_cmd(skb);

	llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);

	skb_reset_mac_header(skb);

	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
		dev_net(p->dev), NULL, skb, NULL, skb->dev,
		br_send_bpdu_finish);
}

static inline void br_set_ticks(unsigned char *dest, int j)
{
	unsigned long ticks = (STP_HZ * j)/ HZ;

	put_unaligned_be16(ticks, dest);
}

static inline int br_get_ticks(const unsigned char *src)
{
	unsigned long ticks = get_unaligned_be16(src);

	return DIV_ROUND_UP(ticks * HZ, STP_HZ);
}

/* called under bridge lock */
void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
{
	unsigned char buf[35];

	if (p->br->stp_enabled != BR_KERNEL_STP)
		return;

	buf[0] = 0;
	buf[1] = 0;
	buf[2] = 0;
	buf[3] = BPDU_TYPE_CONFIG;
	buf[4] = (bpdu->topology_change ? 0x01 : 0) |
		(bpdu->topology_change_ack ? 0x80 : 0);
	buf[5] = bpdu->root.prio[0];
	buf[6] = bpdu->root.prio[1];
	buf[7] = bpdu->root.addr[0];
	buf[8] = bpdu->root.addr[1];
	buf[9] = bpdu->root.addr[2];
	buf[10] = bpdu->root.addr[3];
	buf[11] = bpdu->root.addr[4];
	buf[12] = bpdu->root.addr[5];
	buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
	buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
	buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
	buf[16] = bpdu->root_path_cost & 0xFF;
	buf[17] = bpdu->bridge_id.prio[0];
	buf[18] = bpdu->bridge_id.prio[1];
	buf[19] = bpdu->bridge_id.addr[0];
	buf[20] = bpdu->bridge_id.addr[1];
	buf[21] = bpdu->bridge_id.addr[2];
	buf[22] = bpdu->bridge_id.addr[3];
	buf[23] = bpdu->bridge_id.addr[4];
	buf[24] = bpdu->bridge_id.addr[5];
	buf[25] = (bpdu->port_id >> 8) & 0xFF;
	buf[26] = bpdu->port_id & 0xFF;

	br_set_ticks(buf+27, bpdu->message_age);
	br_set_ticks(buf+29, bpdu->max_age);
	br_set_ticks(buf+31, bpdu->hello_time);
	br_set_ticks(buf+33, bpdu->forward_delay);

	br_send_bpdu(p, buf, 35);
}

/* called under bridge lock */
void br_send_tcn_bpdu(struct net_bridge_port *p)
{
	unsigned char buf[4];

	if (p->br->stp_enabled != BR_KERNEL_STP)
		return;

	buf[0] = 0;
	buf[1] = 0;
	buf[2] = 0;
	buf[3] = BPDU_TYPE_TCN;
	br_send_bpdu(p, buf, 4);
}

/*
 * Called from llc.
 *
 * NO locks, but rcu_read_lock
 */
void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
		struct net_device *dev)
{
	const unsigned char *dest = eth_hdr(skb)->h_dest;
	struct net_bridge_port *p;
	struct net_bridge *br;
	const unsigned char *buf;

	if (!pskb_may_pull(skb, 4))
		goto err;

	/* compare of protocol id and version */
	buf = skb->data;
	if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
		goto err;

	p = br_port_get_check_rcu(dev);
	if (!p)
		goto err;

	br = p->br;
	spin_lock(&br->lock);

	if (br->stp_enabled != BR_KERNEL_STP)
		goto out;

	if (!(br->dev->flags & IFF_UP))
		goto out;

	if (p->state == BR_STATE_DISABLED)
		goto out;

	if (!ether_addr_equal(dest, br->group_addr))
		goto out;

	if (p->flags & BR_BPDU_GUARD) {
		br_notice(br, "BPDU received on blocked port %u(%s)\n",
			  (unsigned int) p->port_no, p->dev->name);
		br_stp_disable_port(p);
		goto out;
	}

	buf = skb_pull(skb, 3);

	if (buf[0] == BPDU_TYPE_CONFIG) {
		struct br_config_bpdu bpdu;

		if (!pskb_may_pull(skb, 32))
			goto out;

		buf = skb->data;
		bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
		bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;

		bpdu.root.prio[0] = buf[2];
		bpdu.root.prio[1] = buf[3];
		bpdu.root.addr[0] = buf[4];
		bpdu.root.addr[1] = buf[5];
		bpdu.root.addr[2] = buf[6];
		bpdu.root.addr[3] = buf[7];
		bpdu.root.addr[4] = buf[8];
		bpdu.root.addr[5] = buf[9];
		bpdu.root_path_cost =
			(buf[10] << 24) |
			(buf[11] << 16) |
			(buf[12] << 8) |
			buf[13];
		bpdu.bridge_id.prio[0] = buf[14];
		bpdu.bridge_id.prio[1] = buf[15];
		bpdu.bridge_id.addr[0] = buf[16];
		bpdu.bridge_id.addr[1] = buf[17];
		bpdu.bridge_id.addr[2] = buf[18];
		bpdu.bridge_id.addr[3] = buf[19];
		bpdu.bridge_id.addr[4] = buf[20];
		bpdu.bridge_id.addr[5] = buf[21];
		bpdu.port_id = (buf[22] << 8) | buf[23];

		bpdu.message_age = br_get_ticks(buf+24);
		bpdu.max_age = br_get_ticks(buf+26);
		bpdu.hello_time = br_get_ticks(buf+28);
		bpdu.forward_delay = br_get_ticks(buf+30);

		if (bpdu.message_age > bpdu.max_age) {
			if (net_ratelimit())
				br_notice(p->br,
					  "port %u config from %pM"
					  " (message_age %ul > max_age %ul)\n",
					  p->port_no,
					  eth_hdr(skb)->h_source,
					  bpdu.message_age, bpdu.max_age);
			goto out;
		}

		br_received_config_bpdu(p, &bpdu);
	} else if (buf[0] == BPDU_TYPE_TCN) {
		br_received_tcn_bpdu(p);
	}
 out:
	spin_unlock(&br->lock);
 err:
	kfree_skb(skb);
}
e028bb8b59e7cfeb0cc9ef03d885182ce8b&amp;id2=49def1853334396f948dcb4cedb9347abb318df5'>diff</a>)</td></tr></table>
<div class='commit-subject'>dmaengine: cppi41: Fix runtime PM timeouts with USB mass storage</div><div class='commit-msg'>Commit fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
added runtime PM support for cppi41, but had corner case issues. Some of
the issues were fixed with commit 098de42ad670 ("dmaengine: cppi41: Fix
unpaired pm runtime when only a USB hub is connected"). That fix however
caused a new regression where we can get error -115 messages with USB on
BeagleBone when connecting a USB mass storage device to a hub.

This is because when connecting a USB mass storage device to a hub, the
initial DMA transfers can take over 200ms to complete and cppi41
autosuspend delay times out.

To fix the issue, we want to implement refcounting for chan_busy array
that contains the active dma transfers. Increasing the autosuspend delay
won't help as that the delay could be potentially seconds, and it's best
to let the USB subsystem to deal with the timeouts on errors.

The earlier attempt for runtime PM was buggy as the pm_runtime_get/put()
calls could get unpaired easily as they did not follow the state of
the chan_busy array as described in commit 098de42ad670 ("dmaengine:
cppi41: Fix unpaired pm runtime when only a USB hub is connected".

Let's fix the issue by adding pm_runtime_get() to where a new transfer
is added to the chan_busy array, and calls to pm_runtime_put() where
chan_busy array entry is cleared. This prevents any autosuspend timeouts
from happening while dma transfers are active.

Fixes: 098de42ad670 ("dmaengine: cppi41: Fix unpaired pm runtime when
only a USB hub is connected")
Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
Cc: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: Bin Liu &lt;b-liu@ti.com&gt;
Cc: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Cc: Kevin Hilman &lt;khilman@baylibre.com&gt;
Cc: Patrick Titiano &lt;ptitiano@baylibre.com&gt;
Cc: Sergei Shtylyov &lt;sergei.shtylyov@cogentembedded.com&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Tested-by: Bin Liu &lt;b-liu@ti.com&gt;
Signed-off-by: Vinod Koul &lt;vinod.koul@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=ae4a3e028bb8b59e7cfeb0cc9ef03d885182ce8b'>Diffstat</a> (limited to 'drivers/usb/host/ohci-omap.c')</div><table summary='diffstat' class='diffstat'>