Re: [PATCH v3 09/15] thunderbolt: Handle hotplug events

[Bjorn Helgaas <bhelgaas@google.com>]

On Mon, May 26, 2014 at 05:18:06PM +0200, Andreas Noever wrote:
> We reveive a plug event callback whenever a thunderbolt device is added

s/reveive/receive/

> or removed. This patch fills in the tb_handle_hotplug method and starts
> reacting to these events by adding/removing switches from the hierarchy.
> 
> Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
> ---
>  drivers/thunderbolt/switch.c | 42 +++++++++++++++++++++++++++++++++++++++-
>  drivers/thunderbolt/tb.c     | 46 +++++++++++++++++++++++++++++++++++++++++++-
>  drivers/thunderbolt/tb.h     |  3 +++
>  3 files changed, 89 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
> index 279b9c5..c092f7c 100644
> --- a/drivers/thunderbolt/switch.c
> +++ b/drivers/thunderbolt/switch.c
> @@ -195,6 +195,24 @@ static void tb_dump_switch(struct tb *tb, struct tb_regs_switch_header *sw)
>  		sw->__unknown1, sw->__unknown4);
>  }
>  
> +struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route)
> +{
> +	u8 next_port = route; /*
> +			       * Routes use a stride of 8 bits,
> +			       * eventhough a port index has 6 bits at most.
> +			       * */
> +	if (route == 0)
> +		return sw;
> +	if (next_port > sw->config.max_port_number)
> +		return 0;
> +	if (tb_is_upstream_port(&sw->ports[next_port]))
> +		return 0;
> +	if (!sw->ports[next_port].remote)
> +		return 0;
> +	return get_switch_at_route(sw->ports[next_port].remote->sw,
> +				   route >> TB_ROUTE_SHIFT);
> +}
> +
>  /**
>   * tb_plug_events_active() - enable/disable plug events on a switch
>   *
> @@ -243,7 +261,8 @@ void tb_switch_free(struct tb_switch *sw)
>  		sw->ports[i].remote = NULL;
>  	}
>  
> -	tb_plug_events_active(sw, false);
> +	if (!sw->is_unplugged)
> +		tb_plug_events_active(sw, false);
>  
>  	kfree(sw->ports);
>  	kfree(sw);
> @@ -327,3 +346,24 @@ err:
>  	return NULL;
>  }
>  
> +/**
> + * tb_sw_set_unpplugged() - set is_unplugged on switch and downstream switches
> + */
> +void tb_sw_set_unpplugged(struct tb_switch *sw)
> +{
> +	int i;
> +	if (sw == sw->tb->root_switch) {
> +		tb_sw_WARN(sw, "cannot unplug root switch\n");
> +		return;
> +	}
> +	if (sw->is_unplugged) {
> +		tb_sw_WARN(sw, "is_unplugged already set\n");
> +		return;
> +	}
> +	sw->is_unplugged = true;
> +	for (i = 0; i <= sw->config.max_port_number; i++) {
> +		if (!tb_is_upstream_port(&sw->ports[i]) && sw->ports[i].remote)
> +			tb_sw_set_unpplugged(sw->ports[i].remote->sw);
> +	}
> +}
> +
> diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
> index 3b716fd..1efcacc 100644
> --- a/drivers/thunderbolt/tb.c
> +++ b/drivers/thunderbolt/tb.c
> @@ -71,11 +71,55 @@ static void tb_handle_hotplug(struct work_struct *work)
>  {
>  	struct tb_hotplug_event *ev = container_of(work, typeof(*ev), work);
>  	struct tb *tb = ev->tb;
> +	struct tb_switch *sw;
> +	struct tb_port *port;
>  	mutex_lock(&tb->lock);
>  	if (!tb->hotplug_active)
>  		goto out; /* during init, suspend or shutdown */
>  
> -	/* do nothing for now */
> +	sw = get_switch_at_route(tb->root_switch, ev->route);
> +	if (!sw) {
> +		tb_warn(tb,
> +			"hotplug event from non existent switch %llx:%x (unplug: %d)\n",
> +			ev->route, ev->port, ev->unplug);
> +		goto out;
> +	}
> +	if (ev->port > sw->config.max_port_number) {
> +		tb_warn(tb,
> +			"hotplug event from non existent port %llx:%x (unplug: %d)\n",
> +			ev->route, ev->port, ev->unplug);
> +		goto out;
> +	}
> +	port = &sw->ports[ev->port];
> +	if (tb_is_upstream_port(port)) {
> +		tb_warn(tb,
> +			"hotplug event for upstream port %llx:%x (unplug: %d)\n",
> +			ev->route, ev->port, ev->unplug);
> +		goto out;
> +	}
> +	if (ev->unplug) {
> +		if (port->remote) {
> +			tb_port_info(port, "unplugged\n");
> +			tb_sw_set_unpplugged(port->remote->sw);
> +			tb_switch_free(port->remote->sw);
> +			port->remote = NULL;
> +		} else {
> +			tb_port_info(port,
> +				     "got unplug event for disconnected port, ignoring\n");
> +		}
> +	} else if (port->remote) {
> +		tb_port_info(port,
> +			     "got plug event for connected port, ignoring\n");
> +	} else {
> +		tb_port_info(port, "hotplug: scanning\n");
> +		tb_scan_port(port);
> +		if (!port->remote) {
> +			tb_port_info(port, "hotplug: no switch found\n");
> +		} else if (port->remote->sw->config.depth > 1) {
> +			tb_sw_warn(port->remote->sw,
> +				   "hotplug: chaining not supported\n");
> +		}
> +	}
>  out:
>  	mutex_unlock(&tb->lock);
>  	kfree(ev);
> diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
> index 70a66fe..661f182 100644
> --- a/drivers/thunderbolt/tb.h
> +++ b/drivers/thunderbolt/tb.h
> @@ -20,6 +20,7 @@ struct tb_switch {
>  	struct tb_port *ports;
>  	struct tb *tb;
>  	int cap_plug_events; /* offset, zero if not found */
> +	bool is_unplugged; /* unplugged, will go away */
>  };
>  
>  /**
> @@ -160,6 +161,8 @@ void thunderbolt_shutdown_and_free(struct tb *tb);
>  
>  struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route);
>  void tb_switch_free(struct tb_switch *sw);
> +void tb_sw_set_unpplugged(struct tb_switch *sw);
> +struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route);
>  
>  int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);
>  
> -- 
> 1.9.3
>