[PATCH 09/10] powerpc/pseries/vas: sysfs interface to export capabilities

[Haren Myneni <haren@linux.ibm.com>]

The hypervisor provides the available VAS GZIP capabilities such
as default or QoS window type and the target available credits in
each type. This patch creates sysfs entries and exports the target,
used and the available credits for each feature.

This interface can be used by the user space to determine the credits
usage or to set the target credits in the case of QoS type (for DLPAR).

/sys/devices/vas/vas0/gzip/def_caps: (default GZIP capabilities)
	avail_creds /* Available credits to use */
	target_creds /* Total credits available. Can be
			 /* changed with DLPAR operation */
	used_creds  /* Used credits */

/sys/devices/vas/vas0/gzip/qos_caps (QoS GZIP capabilities)
	avail_creds
	target_creds
	used_creds

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/Makefile    |   2 +-
 arch/powerpc/platforms/pseries/vas-sysfs.c | 214 +++++++++++++++++++++
 arch/powerpc/platforms/pseries/vas.c       |   6 +
 arch/powerpc/platforms/pseries/vas.h       |   6 +
 4 files changed, 227 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/pseries/vas-sysfs.c

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 41d8aee98da4..349f42c31b65 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -30,6 +30,6 @@ obj-$(CONFIG_PPC_SVM)		+= svm.o
 obj-$(CONFIG_FA_DUMP)		+= rtas-fadump.o
 
 obj-$(CONFIG_SUSPEND)		+= suspend.o
-obj-$(CONFIG_PPC_VAS)		+= vas.o
+obj-$(CONFIG_PPC_VAS)		+= vas.o vas-sysfs.o
 
 obj-$(CONFIG_ARCH_HAS_CC_PLATFORM)	+= cc_platform.o
diff --git a/arch/powerpc/platforms/pseries/vas-sysfs.c b/arch/powerpc/platforms/pseries/vas-sysfs.c
new file mode 100644
index 000000000000..625082bebcb2
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/vas-sysfs.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2016-17 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)
+
+static ssize_t avail_creds_show(struct vas_cop_feat_caps *caps, char *buf)
+{
+	int avail_creds = atomic_read(&caps->target_creds) -
+			atomic_read(&caps->used_creds);
+	return sprintf(buf, "%d\n", avail_creds);
+}
+
+#define sysfs_capbs_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_capbs_entry_read(_name);		\
+	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name,	\
+				0444, _name##_show, NULL);
+
+VAS_ATTR_RO(target_creds);
+VAS_ATTR_RO(used_creds);
+
+static struct vas_sysfs_entry avail_creds_attribute =
+	__ATTR(avail_creds, 0444, avail_creds_show, NULL);
+
+static struct attribute *vas_capab_attrs[] = {
+	&target_creds_attribute.attr,
+	&used_creds_attribute.attr,
+	&avail_creds_attribute.attr,
+	NULL,
+};
+
+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_attr_type = {
+		.release	=	vas_type_release,
+		.sysfs_ops      =       &vas_sysfs_ops,
+		.default_attrs  =       vas_capab_attrs,
+};
+
+static char *vas_caps_kobj_name(struct vas_cop_feat_caps *caps,
+				struct kobject **kobj)
+{
+	if (caps->descriptor == VAS_GZIP_QOS_CAPABILITIES) {
+		*kobj = gzip_caps_kobj;
+		return "qos_caps";
+	} else if (caps->descriptor == VAS_GZIP_DEFAULT_CAPABILITIES) {
+		*kobj = gzip_caps_kobj;
+		return "def_caps";
+	} 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;
+
+	kobject_init(&centry->kobj, &vas_attr_type);
+	centry->caps = caps;
+	name  = vas_caps_kobj_name(caps, &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 PowerVM.
+	 */
+	pseries_vas_kobj = kobject_create_and_add("vas0",
+					&vas_miscdev.this_device->kobj);
+	if (!pseries_vas_kobj) {
+		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);
+			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
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index ed458620f007..c769c8534b3a 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -540,6 +540,10 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 		}
 	}
 
+	rc = sysfs_add_vas_caps(caps);
+	if (rc)
+		return rc;
+
 	copypaste_feat = true;
 
 	return 0;
@@ -826,6 +830,8 @@ static int __init pseries_vas_init(void)
 	caps_all.descriptor = be64_to_cpu(hv_caps->descriptor);
 	caps_all.feat_type = be64_to_cpu(hv_caps->feat_type);
 
+	sysfs_pseries_vas_init(&caps_all);
+
 	hv_cop_caps = kmalloc(sizeof(*hv_cop_caps), GFP_KERNEL);
 	if (!hv_cop_caps) {
 		rc = -ENOMEM;
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 1fbb49a34d48..15bcadf8872a 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -30,6 +30,9 @@
 #define VAS_COPY_PASTE_USER_MODE	0x00000001
 #define VAS_COP_OP_USER_MODE		0x00000010
 
+#define VAS_GZIP_QOS_CAPABILITIES	0x56516F73477A6970
+#define VAS_GZIP_DEFAULT_CAPABILITIES	0x56446566477A6970
+
 /*
  * Co-processor feature - GZIP QoS windows or GZIP default windows
  */
@@ -125,4 +128,7 @@ struct pseries_vas_window {
 	char *name;
 	int fault_virq;
 };
+
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps);
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps);
 #endif /* _VAS_H */
-- 
2.27.0