[PATCH 4/4] drm/xe/pf: Allow to restore auto-provisioning mode

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

After doing tweaks to the VFs provisioning we may want to restore
back the auto-provisioning mode. Allow that unless VFs are still
enabled. This can be also used to release all VFs resources.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
 drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c   | 63 ++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_sriov_pf_helpers.h   | 11 ++++
 drivers/gpu/drm/xe/xe_sriov_pf_provision.c | 18 +++++++
 3 files changed, 92 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
index 97636ed86fb8..a81aa05c5532 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
@@ -13,6 +13,7 @@
 #include "xe_sriov_pf_control.h"
 #include "xe_sriov_pf_debugfs.h"
 #include "xe_sriov_pf_helpers.h"
+#include "xe_sriov_pf_provision.h"
 #include "xe_sriov_pf_service.h"
 #include "xe_sriov_printk.h"
 #include "xe_tile_sriov_pf_debugfs.h"
@@ -43,6 +44,66 @@ static unsigned int extract_vfid(struct dentry *d)
 	return p == extract_xe(d) ? PFID : (uintptr_t)p;
 }
 
+/*
+ *      /sys/kernel/debug/dri/BDF/
+ *      ├── sriov
+ *      │   ├── restore_auto_provisioning
+ *      │   :
+ *      │   ├── pf/
+ *      │   ├── vf1
+ *      │   │   ├── ...
+ */
+
+static ssize_t from_file_write_to_xe_call(struct file *file, const char __user *userbuf,
+					  size_t count, loff_t *ppos,
+					  int (*call)(struct xe_device *))
+{
+	struct dentry *dent = file_dentry(file);
+	struct xe_device *xe = extract_xe(dent);
+	bool yes;
+	int ret;
+
+	if (*ppos)
+		return -EINVAL;
+	ret = kstrtobool_from_user(userbuf, count, &yes);
+	if (ret < 0)
+		return ret;
+	if (yes) {
+		xe_pm_runtime_get(xe);
+		ret = call(xe);
+		xe_pm_runtime_put(xe);
+	}
+	if (ret < 0)
+		return ret;
+	return count;
+}
+
+#define DEFINE_SRIOV_ATTRIBUTE(OP)						\
+static int OP##_show(struct seq_file *s, void *unused)				\
+{										\
+	return 0;								\
+}										\
+static ssize_t OP##_write(struct file *file, const char __user *userbuf,	\
+			  size_t count, loff_t *ppos)				\
+{										\
+	return from_file_write_to_xe_call(file, userbuf, count, ppos,		\
+					  xe_sriov_pf_##OP);			\
+}										\
+DEFINE_SHOW_STORE_ATTRIBUTE(OP)
+
+static inline int xe_sriov_pf_restore_auto_provisioning(struct xe_device *xe)
+{
+	return xe_sriov_pf_provision_set_mode(xe, XE_SRIOV_PROVISIONING_MODE_AUTO);
+}
+
+DEFINE_SRIOV_ATTRIBUTE(restore_auto_provisioning);
+
+static void pf_populate_root(struct xe_device *xe, struct dentry *dent)
+{
+	debugfs_create_file("restore_auto_provisioning", 0200, dent, xe,
+			    &restore_auto_provisioning_fops);
+}
+
 static int simple_show(struct seq_file *m, void *data)
 {
 	struct drm_printer p = drm_seq_file_printer(m);
@@ -167,6 +228,8 @@ void xe_sriov_pf_debugfs_register(struct xe_device *xe, struct dentry *root)
 		return;
 	dent->d_inode->i_private = xe;
 
+	pf_populate_root(xe, dent);
+
 	/*
 	 *      /sys/kernel/debug/dri/BDF/
 	 *      ├── sriov		# d_inode->i_private = (xe_device*)
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
index dd1df950b021..4a4340fb633a 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
@@ -37,6 +37,17 @@ static inline int xe_sriov_pf_get_totalvfs(struct xe_device *xe)
 	return xe->sriov.pf.driver_max_vfs;
 }
 
+/**
+ * xe_sriov_pf_num_vfs() - Number of enabled VFs on the PF.
+ * @xe: the PF &xe_device
+ *
+ * Return: Number of enabled VFs on the PF.
+ */
+static inline unsigned int xe_sriov_pf_num_vfs(const struct xe_device *xe)
+{
+	return pci_num_vf(to_pci_dev(xe->drm.dev));
+}
+
 static inline struct mutex *xe_sriov_pf_master_mutex(struct xe_device *xe)
 {
 	xe_assert(xe, IS_SRIOV_PF(xe));
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
index 7e74175db972..32c281c1dc5d 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_provision.c
@@ -70,6 +70,11 @@ static void pf_unprovision_vfs(struct xe_device *xe, unsigned int num_vfs)
 			xe_gt_sriov_pf_config_release(gt, n, true);
 }
 
+static void pf_unprovision_all_vfs(struct xe_device *xe)
+{
+	pf_unprovision_vfs(xe, xe_sriov_pf_get_totalvfs(xe));
+}
+
 /**
  * xe_sriov_pf_provision_vfs() - Provision VFs in auto-mode.
  * @xe: the PF &xe_device
@@ -117,6 +122,10 @@ int xe_sriov_pf_unprovision_vfs(struct xe_device *xe, unsigned int num_vfs)
  * When changing from AUTO to CUSTOM mode, any already allocated VFs resources
  * will remain allocated and will not be released upon VFs disabling.
  *
+ * When changing back to AUTO mode, if VFs are not enabled, already allocated
+ * VFs resources will be immediately released. If VFs are still enabled, such
+ * mode change is rejected.
+ *
  * This function can only be called on PF.
  *
  * Return: 0 on success or a negative error code on failure.
@@ -128,6 +137,15 @@ int xe_sriov_pf_provision_set_mode(struct xe_device *xe, enum xe_sriov_provision
 	if (mode == xe->sriov.pf.provision.mode)
 		return 0;
 
+	if (mode == XE_SRIOV_PROVISIONING_MODE_AUTO) {
+		if (xe_sriov_pf_num_vfs(xe)) {
+			xe_sriov_dbg(xe, "can't restore %s: VFs must be disabled!\n",
+				     mode_to_string(mode));
+			return -EBUSY;
+		}
+		pf_unprovision_all_vfs(xe);
+	}
+
 	xe_sriov_dbg(xe, "mode %s changed to %s by %ps\n",
 		     mode_to_string(xe->sriov.pf.provision.mode),
 		     mode_to_string(mode), __builtin_return_address(0));
-- 
2.47.1