1 files changed, 281 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/vas-sysfs.c b/arch/powerpc/platforms/pseries/vas-sysfs.c
new file mode 100644
index 000000000000..f9f682724e77
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/vas-sysfs.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2022-23 IBM Corp.
+ */
+
+#define pr_fmt(fmt) "vas: " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include "vas.h"
+
+#ifdef CONFIG_SYSFS
+static struct kobject *pseries_vas_kobj;
+static struct kobject *gzip_caps_kobj;
+
+struct vas_caps_entry {
+	struct kobject kobj;
+	struct vas_cop_feat_caps *caps;
+};
+
+#define to_caps_entry(entry) container_of(entry, struct vas_caps_entry, kobj)
+
+/*
+ * This function is used to get the notification from the drmgr when
+ * QoS credits are changed.
+ */
+static ssize_t update_total_credits_store(struct vas_cop_feat_caps *caps,
+						const char *buf, size_t count)
+{
+	int err;
+	u16 creds;
+
+	err = kstrtou16(buf, 0, &creds);
+	/*
+	 * The user space interface from the management console
+	 * notifies OS with the new QoS credits and then the
+	 * hypervisor. So OS has to use this new credits value
+	 * and reconfigure VAS windows (close or reopen depends
+	 * on the credits available) instead of depending on VAS
+	 * QoS capabilities from the hypervisor.
+	 */
+	if (!err)
+		err = vas_reconfig_capabilties(caps->win_type, creds);
+
+	if (err)
+		return -EINVAL;
+
+	pr_info("Set QoS total credits %u\n", creds);
+
+	return count;
+}
+
+#define sysfs_caps_entry_read(_name)					\
+static ssize_t _name##_show(struct vas_cop_feat_caps *caps, char *buf) 	\
+{									\
+	return sprintf(buf, "%d\n", atomic_read(&caps->_name));	\
+}
+
+struct vas_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct vas_cop_feat_caps *, char *);
+	ssize_t (*store)(struct vas_cop_feat_caps *, const char *, size_t);
+};
+
+#define VAS_ATTR_RO(_name)	\
+	sysfs_caps_entry_read(_name);		\
+	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name,	\
+				0444, _name##_show, NULL);
+
+/*
+ * Create sysfs interface:
+ * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities
+ *	This directory contains the following VAS GZIP capabilities
+ *	for the default credit type.
+ * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_total_credits
+ *	Total number of default credits assigned to the LPAR which
+ *	can be changed with DLPAR operation.
+ * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_used_credits
+ *	Number of credits used by the user space. One credit will
+ *	be assigned for each window open.
+ *
+ * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities
+ *	This directory contains the following VAS GZIP capabilities
+ *	for the Quality of Service (QoS) credit type.
+ * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_total_credits
+ *	Total number of QoS credits assigned to the LPAR. The user
+ *	has to define this value using HMC interface. It can be
+ *	changed dynamically by the user.
+ * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_used_credits
+ *	Number of credits used by the user space.
+ * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/update_total_credits
+ *	Update total QoS credits dynamically
+ */
+
+VAS_ATTR_RO(nr_total_credits);
+VAS_ATTR_RO(nr_used_credits);
+
+static struct vas_sysfs_entry update_total_credits_attribute =
+	__ATTR(update_total_credits, 0200, NULL, update_total_credits_store);
+
+static struct attribute *vas_def_capab_attrs[] = {
+	&nr_total_credits_attribute.attr,
+	&nr_used_credits_attribute.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(vas_def_capab);
+
+static struct attribute *vas_qos_capab_attrs[] = {
+	&nr_total_credits_attribute.attr,
+	&nr_used_credits_attribute.attr,
+	&update_total_credits_attribute.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(vas_qos_capab);
+
+static ssize_t vas_type_show(struct kobject *kobj, struct attribute *attr,
+			     char *buf)
+{
+	struct vas_caps_entry *centry;
+	struct vas_cop_feat_caps *caps;
+	struct vas_sysfs_entry *entry;
+
+	centry = to_caps_entry(kobj);
+	caps = centry->caps;
+	entry = container_of(attr, struct vas_sysfs_entry, attr);
+
+	if (!entry->show)
+		return -EIO;
+
+	return entry->show(caps, buf);
+}
+
+static ssize_t vas_type_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct vas_caps_entry *centry;
+	struct vas_cop_feat_caps *caps;
+	struct vas_sysfs_entry *entry;
+
+	centry = to_caps_entry(kobj);
+	caps = centry->caps;
+	entry = container_of(attr, struct vas_sysfs_entry, attr);
+	if (!entry->store)
+		return -EIO;
+
+	return entry->store(caps, buf, count);
+}
+
+static void vas_type_release(struct kobject *kobj)
+{
+	struct vas_caps_entry *centry = to_caps_entry(kobj);
+	kfree(centry);
+}
+
+static const struct sysfs_ops vas_sysfs_ops = {
+	.show	=	vas_type_show,
+	.store	=	vas_type_store,
+};
+
+static struct kobj_type vas_def_attr_type = {
+		.release	=	vas_type_release,
+		.sysfs_ops      =       &vas_sysfs_ops,
+		.default_groups	=	vas_def_capab_groups,
+};
+
+static struct kobj_type vas_qos_attr_type = {
+		.release	=	vas_type_release,
+		.sysfs_ops	=	&vas_sysfs_ops,
+		.default_groups	=	vas_qos_capab_groups,
+};
+
+static char *vas_caps_kobj_name(struct vas_caps_entry *centry,
+				struct kobject **kobj)
+{
+	struct vas_cop_feat_caps *caps = centry->caps;
+
+	if (caps->descriptor == VAS_GZIP_QOS_CAPABILITIES) {
+		kobject_init(&centry->kobj, &vas_qos_attr_type);
+		*kobj = gzip_caps_kobj;
+		return "qos_capabilities";
+	} else if (caps->descriptor == VAS_GZIP_DEFAULT_CAPABILITIES) {
+		kobject_init(&centry->kobj, &vas_def_attr_type);
+		*kobj = gzip_caps_kobj;
+		return "default_capabilities";
+	} else
+		return "Unknown";
+}
+
+/*
+ * Add feature specific capability dir entry.
+ * Ex: VDefGzip or VQosGzip
+ */
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
+{
+	struct vas_caps_entry *centry;
+	struct kobject *kobj = NULL;
+	int ret = 0;
+	char *name;
+
+	centry = kzalloc(sizeof(*centry), GFP_KERNEL);
+	if (!centry)
+		return -ENOMEM;
+
+	centry->caps = caps;
+	name  = vas_caps_kobj_name(centry, &kobj);
+
+	if (kobj) {
+		ret = kobject_add(&centry->kobj, kobj, "%s", name);
+
+		if (ret) {
+			pr_err("VAS: sysfs kobject add / event failed %d\n",
+					ret);
+			kobject_put(&centry->kobj);
+		}
+	}
+
+	return ret;
+}
+
+static struct miscdevice vas_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vas",
+};
+
+/*
+ * Add VAS and VasCaps (overall capabilities) dir entries.
+ */
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
+{
+	int ret;
+
+	ret = misc_register(&vas_miscdev);
+	if (ret < 0) {
+		pr_err("%s: register vas misc device failed\n", __func__);
+		return ret;
+	}
+
+	/*
+	 * The hypervisor does not expose multiple VAS instances, but can
+	 * see multiple VAS instances on PowerNV. So create 'vas0' directory
+	 * on pseries.
+	 */
+	pseries_vas_kobj = kobject_create_and_add("vas0",
+					&vas_miscdev.this_device->kobj);
+	if (!pseries_vas_kobj) {
+		misc_deregister(&vas_miscdev);
+		pr_err("Failed to create VAS sysfs entry\n");
+		return -ENOMEM;
+	}
+
+	if ((vas_caps->feat_type & VAS_GZIP_QOS_FEAT_BIT) ||
+		(vas_caps->feat_type & VAS_GZIP_DEF_FEAT_BIT)) {
+		gzip_caps_kobj = kobject_create_and_add("gzip",
+						       pseries_vas_kobj);
+		if (!gzip_caps_kobj) {
+			pr_err("Failed to create VAS GZIP capability entry\n");
+			kobject_put(pseries_vas_kobj);
+			misc_deregister(&vas_miscdev);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+#else
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
+{
+	return 0;
+}
+
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
+{
+	return 0;
+}
+#endif