thunderbolt: Add support for runtime PM

When Thunderbolt host controller is set to RTD3 mode (Runtime D3) it is
present all the time. Because of this it is important to runtime suspend
the controller whenever possible. In case of ICM we have following rules
which all needs to be true before the host controller can be put to D3:

  - The controller firmware reports to support RTD3
  - All the connected devices announce support for RTD3
  - There is no active XDomain connection

Implement this using standard Linux runtime PM APIs so that when all the
children devices are runtime suspended, the Thunderbolt host controller
PCI device is runtime suspended as well. The ICM firmware then starts
powering down power domains towards RTD3 but it can prevent this if it
detects that there is an active Display Port stream (this is not visible
to the software, though).

The Thunderbolt host controller will be runtime resumed either when
there is a remote wake event (device is connected or disconnected), or
when there is access from userspace that requires hardware access.

Signed-off-by: Mika Westerberg <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: westeri

drivers/thunderbolt/domain.c

@@ -12,6 +12,7 @@
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/random.h>
 #include <crypto/hash.h>
@@ -132,6 +133,8 @@ static ssize_t boot_acl_show(struct device *dev, struct device_attribute *attr,
 	if (!uuids)
 		return -ENOMEM;
 
+	pm_runtime_get_sync(&tb->dev);
+
 	if (mutex_lock_interruptible(&tb->lock)) {
 		ret = -ERESTARTSYS;
 		goto out;
@@ -153,7 +156,10 @@ static ssize_t boot_acl_show(struct device *dev, struct device_attribute *attr,
 	}
 
 out:
+	pm_runtime_mark_last_busy(&tb->dev);
+	pm_runtime_put_autosuspend(&tb->dev);
 	kfree(uuids);
+
 	return ret;
 }
 
@@ -208,9 +214,11 @@ static ssize_t boot_acl_store(struct device *dev, struct device_attribute *attr,
 		goto err_free_acl;
 	}
 
+	pm_runtime_get_sync(&tb->dev);
+
 	if (mutex_lock_interruptible(&tb->lock)) {
 		ret = -ERESTARTSYS;
-		goto err_free_acl;
+		goto err_rpm_put;
 	}
 	ret = tb->cm_ops->set_boot_acl(tb, acl, tb->nboot_acl);
 	if (!ret) {
@@ -219,6 +227,9 @@ static ssize_t boot_acl_store(struct device *dev, struct device_attribute *attr,
 	}
 	mutex_unlock(&tb->lock);
 
+err_rpm_put:
+	pm_runtime_mark_last_busy(&tb->dev);
+	pm_runtime_put_autosuspend(&tb->dev);
 err_free_acl:
 	kfree(acl);
 err_free_str:
@@ -430,6 +441,13 @@ int tb_domain_add(struct tb *tb)
 	/* This starts event processing */
 	mutex_unlock(&tb->lock);
 
+	pm_runtime_no_callbacks(&tb->dev);
+	pm_runtime_set_active(&tb->dev);
+	pm_runtime_enable(&tb->dev);
+	pm_runtime_set_autosuspend_delay(&tb->dev, TB_AUTOSUSPEND_DELAY);
+	pm_runtime_mark_last_busy(&tb->dev);
+	pm_runtime_use_autosuspend(&tb->dev);
+
 	return 0;
 
 err_domain_del:
@@ -518,6 +536,28 @@ void tb_domain_complete(struct tb *tb)
 		tb->cm_ops->complete(tb);
 }
 
+int tb_domain_runtime_suspend(struct tb *tb)
+{
+	if (tb->cm_ops->runtime_suspend) {
+		int ret = tb->cm_ops->runtime_suspend(tb);
+		if (ret)
+			return ret;
+	}
+	tb_ctl_stop(tb->ctl);
+	return 0;
+}
+
+int tb_domain_runtime_resume(struct tb *tb)
+{
+	tb_ctl_start(tb->ctl);
+	if (tb->cm_ops->runtime_resume) {
+		int ret = tb->cm_ops->runtime_resume(tb);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 /**
  * tb_domain_approve_switch() - Approve switch
  * @tb: Domain the switch belongs to

drivers/thunderbolt/icm.c

@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
+#include <linux/pm_runtime.h>
 #include <linux/platform_data/x86/apple.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
@@ -57,6 +58,7 @@
  *	     (only set when @upstream_port is not %NULL)
  * @safe_mode: ICM is in safe mode
  * @max_boot_acl: Maximum number of preboot ACL entries (%0 if not supported)
+ * @rpm: Does the controller support runtime PM (RTD3)
  * @is_supported: Checks if we can support ICM on this controller
  * @get_mode: Read and return the ICM firmware mode (optional)
  * @get_route: Find a route string for given switch
@@ -74,13 +76,14 @@ struct icm {
 	size_t max_boot_acl;
 	int vnd_cap;
 	bool safe_mode;
+	bool rpm;
 	bool (*is_supported)(struct tb *tb);
 	int (*get_mode)(struct tb *tb);
 	int (*get_route)(struct tb *tb, u8 link, u8 depth, u64 *route);
 	void (*save_devices)(struct tb *tb);
 	int (*driver_ready)(struct tb *tb,
 			    enum tb_security_level *security_level,
-			    size_t *nboot_acl);
+			    size_t *nboot_acl, bool *rpm);
 	void (*device_connected)(struct tb *tb,
 				 const struct icm_pkg_header *hdr);
 	void (*device_disconnected)(struct tb *tb,
@@ -97,6 +100,47 @@ struct icm_notification {
 	struct tb *tb;
 };
 
+struct ep_name_entry {
+	u8 len;
+	u8 type;
+	u8 data[0];
+};
+
+#define EP_NAME_INTEL_VSS	0x10
+
+/* Intel Vendor specific structure */
+struct intel_vss {
+	u16 vendor;
+	u16 model;
+	u8 mc;
+	u8 flags;
+	u16 pci_devid;
+	u32 nvm_version;
+};
+
+#define INTEL_VSS_FLAGS_RTD3	BIT(0)
+
+static const struct intel_vss *parse_intel_vss(const void *ep_name, size_t size)
+{
+	const void *end = ep_name + size;
+
+	while (ep_name < end) {
+		const struct ep_name_entry *ep = ep_name;
+
+		if (!ep->len)
+			break;
+		if (ep_name + ep->len > end)
+			break;
+
+		if (ep->type == EP_NAME_INTEL_VSS)
+			return (const struct intel_vss *)ep->data;
+
+		ep_name += ep->len;
+	}
+
+	return NULL;
+}
+
 static inline struct tb *icm_to_tb(struct icm *icm)
 {
 	return ((void *)icm - sizeof(struct tb));
@@ -267,7 +311,7 @@ static void icm_fr_save_devices(struct tb *tb)
 
 static int
 icm_fr_driver_ready(struct tb *tb, enum tb_security_level *security_level,
-		    size_t *nboot_acl)
+		    size_t *nboot_acl, bool *rpm)
 {
 	struct icm_fr_pkg_driver_ready_response reply;
 	struct icm_pkg_driver_ready request = {
@@ -417,15 +461,19 @@ static int icm_fr_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
 }
 
 static void add_switch(struct tb_switch *parent_sw, u64 route,
-		       const uuid_t *uuid, u8 connection_id, u8 connection_key,
+		       const uuid_t *uuid, const u8 *ep_name,
+		       size_t ep_name_size, u8 connection_id, u8 connection_key,
 		       u8 link, u8 depth, enum tb_security_level security_level,
 		       bool authorized, bool boot)
 {
+	const struct intel_vss *vss;
 	struct tb_switch *sw;
 
+	pm_runtime_get_sync(&parent_sw->dev);
+
 	sw = tb_switch_alloc(parent_sw->tb, &parent_sw->dev, route);
 	if (!sw)
-		return;
+		goto out;
 
 	sw->uuid = kmemdup(uuid, sizeof(*uuid), GFP_KERNEL);
 	sw->connection_id = connection_id;
@@ -436,15 +484,22 @@ static void add_switch(struct tb_switch *parent_sw, u64 route,
 	sw->security_level = security_level;
 	sw->boot = boot;
 
+	vss = parse_intel_vss(ep_name, ep_name_size);
+	if (vss)
+		sw->rpm = !!(vss->flags & INTEL_VSS_FLAGS_RTD3);
+
 	/* Link the two switches now */
 	tb_port_at(route, parent_sw)->remote = tb_upstream_port(sw);
 	tb_upstream_port(sw)->remote = tb_port_at(route, parent_sw);
 
 	if (tb_switch_add(sw)) {
 		tb_port_at(tb_route(sw), parent_sw)->remote = NULL;
 		tb_switch_put(sw);
-		return;
 	}
+
+out:
+	pm_runtime_mark_last_busy(&parent_sw->dev);
+	pm_runtime_put_autosuspend(&parent_sw->dev);
 }
 
 static void update_switch(struct tb_switch *parent_sw, struct tb_switch *sw,
@@ -484,16 +539,22 @@ static void add_xdomain(struct tb_switch *sw, u64 route,
 {
 	struct tb_xdomain *xd;
 
+	pm_runtime_get_sync(&sw->dev);
+
 	xd = tb_xdomain_alloc(sw->tb, &sw->dev, route, local_uuid, remote_uuid);
 	if (!xd)
-		return;
+		goto out;
 
 	xd->link = link;
 	xd->depth = depth;
 
 	tb_port_at(route, sw)->xdomain = xd;
 
 	tb_xdomain_add(xd);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
 }
 
 static void update_xdomain(struct tb_xdomain *xd, u64 route, u8 link)
@@ -631,7 +692,8 @@ icm_fr_device_connected(struct tb *tb, const struct icm_pkg_header *hdr)
 		return;
 	}
 
-	add_switch(parent_sw, route, &pkg->ep_uuid, pkg->connection_id,
+	add_switch(parent_sw, route, &pkg->ep_uuid, (const u8 *)pkg->ep_name,
+		   sizeof(pkg->ep_name), pkg->connection_id,
 		   pkg->connection_key, link, depth, security_level,
 		   authorized, boot);
 
@@ -779,7 +841,7 @@ icm_fr_xdomain_disconnected(struct tb *tb, const struct icm_pkg_header *hdr)
 
 static int
 icm_tr_driver_ready(struct tb *tb, enum tb_security_level *security_level,
-		    size_t *nboot_acl)
+		    size_t *nboot_acl, bool *rpm)
 {
 	struct icm_tr_pkg_driver_ready_response reply;
 	struct icm_pkg_driver_ready request = {
@@ -798,6 +860,9 @@ icm_tr_driver_ready(struct tb *tb, enum tb_security_level *security_level,
 	if (nboot_acl)
 		*nboot_acl = (reply.info & ICM_TR_INFO_BOOT_ACL_MASK) >>
 				ICM_TR_INFO_BOOT_ACL_SHIFT;
+	if (rpm)
+		*rpm = !!(reply.hdr.flags & ICM_TR_FLAGS_RTD3);
+
 	return 0;
 }
 
@@ -1027,7 +1092,8 @@ icm_tr_device_connected(struct tb *tb, const struct icm_pkg_header *hdr)
 		return;
 	}
 
-	add_switch(parent_sw, route, &pkg->ep_uuid, pkg->connection_id,
+	add_switch(parent_sw, route, &pkg->ep_uuid, (const u8 *)pkg->ep_name,
+		   sizeof(pkg->ep_name), pkg->connection_id,
 		   0, 0, 0, security_level, authorized, boot);
 
 	tb_switch_put(parent_sw);
@@ -1206,7 +1272,7 @@ static int icm_ar_get_mode(struct tb *tb)
 
 static int
 icm_ar_driver_ready(struct tb *tb, enum tb_security_level *security_level,
-		    size_t *nboot_acl)
+		    size_t *nboot_acl, bool *rpm)
 {
 	struct icm_ar_pkg_driver_ready_response reply;
 	struct icm_pkg_driver_ready request = {
@@ -1225,6 +1291,9 @@ icm_ar_driver_ready(struct tb *tb, enum tb_security_level *security_level,
 	if (nboot_acl && (reply.info & ICM_AR_INFO_BOOT_ACL_SUPPORTED))
 		*nboot_acl = (reply.info & ICM_AR_INFO_BOOT_ACL_MASK) >>
 				ICM_AR_INFO_BOOT_ACL_SHIFT;
+	if (rpm)
+		*rpm = !!(reply.hdr.flags & ICM_AR_FLAGS_RTD3);
+
 	return 0;
 }
 
@@ -1378,13 +1447,13 @@ static void icm_handle_event(struct tb *tb, enum tb_cfg_pkg_type type,
 
 static int
 __icm_driver_ready(struct tb *tb, enum tb_security_level *security_level,
-		   size_t *nboot_acl)
+		   size_t *nboot_acl, bool *rpm)
 {
 	struct icm *icm = tb_priv(tb);
 	unsigned int retries = 50;
 	int ret;
 
-	ret = icm->driver_ready(tb, security_level, nboot_acl);
+	ret = icm->driver_ready(tb, security_level, nboot_acl, rpm);
 	if (ret) {
 		tb_err(tb, "failed to send driver ready to ICM\n");
 		return ret;
@@ -1654,7 +1723,8 @@ static int icm_driver_ready(struct tb *tb)
 		return 0;
 	}
 
-	ret = __icm_driver_ready(tb, &tb->security_level, &tb->nboot_acl);
+	ret = __icm_driver_ready(tb, &tb->security_level, &tb->nboot_acl,
+				 &icm->rpm);
 	if (ret)
 		return ret;
 
@@ -1760,7 +1830,7 @@ static void icm_complete(struct tb *tb)
 	 * Now all existing children should be resumed, start events
 	 * from ICM to get updated status.
 	 */
-	__icm_driver_ready(tb, NULL, NULL);
+	__icm_driver_ready(tb, NULL, NULL, NULL);
 
 	/*
 	 * We do not get notifications of devices that have been
@@ -1770,6 +1840,22 @@ static void icm_complete(struct tb *tb)
 	queue_delayed_work(tb->wq, &icm->rescan_work, msecs_to_jiffies(500));
 }
 
+static int icm_runtime_suspend(struct tb *tb)
+{
+	nhi_mailbox_cmd(tb->nhi, NHI_MAILBOX_DRV_UNLOADS, 0);
+	return 0;
+}
+
+static int icm_runtime_resume(struct tb *tb)
+{
+	/*
+	 * We can reuse the same resume functionality than with system
+	 * suspend.
+	 */
+	icm_complete(tb);
+	return 0;
+}
+
 static int icm_start(struct tb *tb)
 {
 	struct icm *icm = tb_priv(tb);
@@ -1788,6 +1874,7 @@ static int icm_start(struct tb *tb)
 	 * prevent root switch NVM upgrade on Macs for now.
 	 */
 	tb->root_switch->no_nvm_upgrade = x86_apple_machine;
+	tb->root_switch->rpm = icm->rpm;
 
 	ret = tb_switch_add(tb->root_switch);
 	if (ret) {
@@ -1836,6 +1923,8 @@ static const struct tb_cm_ops icm_ar_ops = {
 	.stop = icm_stop,
 	.suspend = icm_suspend,
 	.complete = icm_complete,
+	.runtime_suspend = icm_runtime_suspend,
+	.runtime_resume = icm_runtime_resume,
 	.handle_event = icm_handle_event,
 	.get_boot_acl = icm_ar_get_boot_acl,
 	.set_boot_acl = icm_ar_set_boot_acl,
@@ -1854,6 +1943,8 @@ static const struct tb_cm_ops icm_tr_ops = {
 	.stop = icm_stop,
 	.suspend = icm_suspend,
 	.complete = icm_complete,
+	.runtime_suspend = icm_runtime_suspend,
+	.runtime_resume = icm_runtime_resume,
 	.handle_event = icm_handle_event,
 	.get_boot_acl = icm_ar_get_boot_acl,
 	.set_boot_acl = icm_ar_set_boot_acl,