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/*
* Thunderbolt Cactus Ridge driver - bus logic (NHI independent)
*
* Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
*/
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include "tb.h"
#include "tb_regs.h"
/* enumeration & hot plug handling */
static void tb_scan_port(struct tb_port *port);
/**
* tb_scan_switch() - scan for and initialize downstream switches
*/
static void tb_scan_switch(struct tb_switch *sw)
{
int i;
for (i = 1; i <= sw->config.max_port_number; i++)
tb_scan_port(&sw->ports[i]);
}
/**
* tb_scan_port() - check for and initialize switches below port
*/
static void tb_scan_port(struct tb_port *port)
{
struct tb_switch *sw;
if (tb_is_upstream_port(port))
return;
if (port->config.type != TB_TYPE_PORT)
return;
if (tb_wait_for_port(port, false) <= 0)
return;
if (port->remote) {
tb_port_WARN(port, "port already has a remote!\n");
return;
}
sw = tb_switch_alloc(port->sw->tb, tb_downstream_route(port));
if (!sw)
return;
port->remote = tb_upstream_port(sw);
tb_upstream_port(sw)->remote = port;
tb_scan_switch(sw);
}
/* hotplug handling */
struct tb_hotplug_event {
struct work_struct work;
struct tb *tb;
u64 route;
u8 port;
bool unplug;
};
/**
* tb_handle_hotplug() - handle hotplug event
*
* Executes on tb->wq.
*/
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 */
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);
}
/**
* tb_schedule_hotplug_handler() - callback function for the control channel
*
* Delegates to tb_handle_hotplug.
*/
static void tb_schedule_hotplug_handler(void *data, u64 route, u8 port,
bool unplug)
{
struct tb *tb = data;
struct tb_hotplug_event *ev = kmalloc(sizeof(*ev), GFP_KERNEL);
if (!ev)
return;
INIT_WORK(&ev->work, tb_handle_hotplug);
ev->tb = tb;
ev->route = route;
ev->port = port;
ev->unplug = unplug;
queue_work(tb->wq, &ev->work);
}
/**
* thunderbolt_shutdown_and_free() - shutdown everything
*
* Free all switches and the config channel.
*
* Used in the error path of thunderbolt_alloc_and_start.
*/
void thunderbolt_shutdown_and_free(struct tb *tb)
{
mutex_lock(&tb->lock);
if (tb->root_switch)
tb_switch_free(tb->root_switch);
tb->root_switch = NULL;
if (tb->ctl) {
tb_ctl_stop(tb->ctl);
tb_ctl_free(tb->ctl);
}
tb->ctl = NULL;
tb->hotplug_active = false; /* signal tb_handle_hotplug to quit */
/* allow tb_handle_hotplug to acquire the lock */
mutex_unlock(&tb->lock);
if (tb->wq) {
flush_workqueue(tb->wq);
destroy_workqueue(tb->wq);
tb->wq = NULL;
}
mutex_destroy(&tb->lock);
kfree(tb);
}
/**
* thunderbolt_alloc_and_start() - setup the thunderbolt bus
*
* Allocates a tb_cfg control channel, initializes the root switch, enables
* plug events and activates pci devices.
*
* Return: Returns NULL on error.
*/
struct tb *thunderbolt_alloc_and_start(struct tb_nhi *nhi)
{
struct tb *tb;
BUILD_BUG_ON(sizeof(struct tb_regs_switch_header) != 5 * 4);
BUILD_BUG_ON(sizeof(struct tb_regs_port_header) != 8 * 4);
BUILD_BUG_ON(sizeof(struct tb_regs_hop) != 2 * 4);
tb = kzalloc(sizeof(*tb), GFP_KERNEL);
if (!tb)
return NULL;
tb->nhi = nhi;
mutex_init(&tb->lock);
mutex_lock(&tb->lock);
tb->wq = alloc_ordered_workqueue("thunderbolt", 0);
if (!tb->wq)
goto err_locked;
tb->ctl = tb_ctl_alloc(tb->nhi, tb_schedule_hotplug_handler, tb);
if (!tb->ctl)
goto err_locked;
/*
* tb_schedule_hotplug_handler may be called as soon as the config
* channel is started. Thats why we have to hold the lock here.
*/
tb_ctl_start(tb->ctl);
tb->root_switch = tb_switch_alloc(tb, 0);
if (!tb->root_switch)
goto err_locked;
/* Full scan to discover devices added before the driver was loaded. */
tb_scan_switch(tb->root_switch);
/* Allow tb_handle_hotplug to progress events */
tb->hotplug_active = true;
mutex_unlock(&tb->lock);
return tb;
err_locked:
mutex_unlock(&tb->lock);
thunderbolt_shutdown_and_free(tb);
return NULL;
}
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