1 files changed, 294 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-sysparam.c b/arch/powerpc/platforms/powernv/opal-sysparam.c
new file mode 100644
index 000000000..a12312afe
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-sysparam.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PowerNV system parameter code
+ *
+ * Copyright (C) 2013 IBM
+ */
+
+#include <linux/kobject.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/gfp.h>
+#include <linux/stat.h>
+#include <asm/opal.h>
+
+#define MAX_PARAM_DATA_LEN	64
+
+static DEFINE_MUTEX(opal_sysparam_mutex);
+static struct kobject *sysparam_kobj;
+static void *param_data_buf;
+
+struct param_attr {
+	struct list_head list;
+	u32 param_id;
+	u32 param_size;
+	struct kobj_attribute kobj_attr;
+};
+
+static ssize_t opal_get_sys_param(u32 param_id, u32 length, void *buffer)
+{
+	struct opal_msg msg;
+	ssize_t ret;
+	int token;
+
+	token = opal_async_get_token_interruptible();
+	if (token < 0) {
+		if (token != -ERESTARTSYS)
+			pr_err("%s: Couldn't get the token, returning\n",
+					__func__);
+		ret = token;
+		goto out;
+	}
+
+	ret = opal_get_param(token, param_id, (u64)buffer, length);
+	if (ret != OPAL_ASYNC_COMPLETION) {
+		ret = opal_error_code(ret);
+		goto out_token;
+	}
+
+	ret = opal_async_wait_response(token, &msg);
+	if (ret) {
+		pr_err("%s: Failed to wait for the async response, %zd\n",
+				__func__, ret);
+		goto out_token;
+	}
+
+	ret = opal_error_code(opal_get_async_rc(msg));
+
+out_token:
+	opal_async_release_token(token);
+out:
+	return ret;
+}
+
+static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
+{
+	struct opal_msg msg;
+	int ret, token;
+
+	token = opal_async_get_token_interruptible();
+	if (token < 0) {
+		if (token != -ERESTARTSYS)
+			pr_err("%s: Couldn't get the token, returning\n",
+					__func__);
+		ret = token;
+		goto out;
+	}
+
+	ret = opal_set_param(token, param_id, (u64)buffer, length);
+
+	if (ret != OPAL_ASYNC_COMPLETION) {
+		ret = opal_error_code(ret);
+		goto out_token;
+	}
+
+	ret = opal_async_wait_response(token, &msg);
+	if (ret) {
+		pr_err("%s: Failed to wait for the async response, %d\n",
+				__func__, ret);
+		goto out_token;
+	}
+
+	ret = opal_error_code(opal_get_async_rc(msg));
+
+out_token:
+	opal_async_release_token(token);
+out:
+	return ret;
+}
+
+static ssize_t sys_param_show(struct kobject *kobj,
+		struct kobj_attribute *kobj_attr, char *buf)
+{
+	struct param_attr *attr = container_of(kobj_attr, struct param_attr,
+			kobj_attr);
+	ssize_t ret;
+
+	mutex_lock(&opal_sysparam_mutex);
+	ret = opal_get_sys_param(attr->param_id, attr->param_size,
+			param_data_buf);
+	if (ret)
+		goto out;
+
+	memcpy(buf, param_data_buf, attr->param_size);
+
+	ret = attr->param_size;
+out:
+	mutex_unlock(&opal_sysparam_mutex);
+	return ret;
+}
+
+static ssize_t sys_param_store(struct kobject *kobj,
+		struct kobj_attribute *kobj_attr, const char *buf, size_t count)
+{
+	struct param_attr *attr = container_of(kobj_attr, struct param_attr,
+			kobj_attr);
+	ssize_t ret;
+
+        /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
+        if (count > MAX_PARAM_DATA_LEN)
+                count = MAX_PARAM_DATA_LEN;
+
+	mutex_lock(&opal_sysparam_mutex);
+	memcpy(param_data_buf, buf, count);
+	ret = opal_set_sys_param(attr->param_id, attr->param_size,
+			param_data_buf);
+	mutex_unlock(&opal_sysparam_mutex);
+	if (!ret)
+		ret = count;
+	return ret;
+}
+
+void __init opal_sys_param_init(void)
+{
+	struct device_node *sysparam;
+	struct param_attr *attr;
+	u32 *id, *size;
+	int count, i;
+	u8 *perm;
+
+	if (!opal_kobj) {
+		pr_warn("SYSPARAM: opal kobject is not available\n");
+		goto out;
+	}
+
+	/* Some systems do not use sysparams; this is not an error */
+	sysparam = of_find_node_by_path("/ibm,opal/sysparams");
+	if (!sysparam)
+		goto out;
+
+	if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
+		pr_err("SYSPARAM: Opal sysparam node not compatible\n");
+		goto out_node_put;
+	}
+
+	sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
+	if (!sysparam_kobj) {
+		pr_err("SYSPARAM: Failed to create sysparam kobject\n");
+		goto out_node_put;
+	}
+
+	/* Allocate big enough buffer for any get/set transactions */
+	param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
+	if (!param_data_buf) {
+		pr_err("SYSPARAM: Failed to allocate memory for param data "
+				"buf\n");
+		goto out_kobj_put;
+	}
+
+	/* Number of parameters exposed through DT */
+	count = of_property_count_strings(sysparam, "param-name");
+	if (count < 0) {
+		pr_err("SYSPARAM: No string found of property param-name in "
+				"the node %pOFn\n", sysparam);
+		goto out_param_buf;
+	}
+
+	id = kcalloc(count, sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		pr_err("SYSPARAM: Failed to allocate memory to read parameter "
+				"id\n");
+		goto out_param_buf;
+	}
+
+	size = kcalloc(count, sizeof(*size), GFP_KERNEL);
+	if (!size) {
+		pr_err("SYSPARAM: Failed to allocate memory to read parameter "
+				"size\n");
+		goto out_free_id;
+	}
+
+	perm = kcalloc(count, sizeof(*perm), GFP_KERNEL);
+	if (!perm) {
+		pr_err("SYSPARAM: Failed to allocate memory to read supported "
+				"action on the parameter");
+		goto out_free_size;
+	}
+
+	if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
+		pr_err("SYSPARAM: Missing property param-id in the DT\n");
+		goto out_free_perm;
+	}
+
+	if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
+		pr_err("SYSPARAM: Missing property param-len in the DT\n");
+		goto out_free_perm;
+	}
+
+
+	if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
+		pr_err("SYSPARAM: Missing property param-perm in the DT\n");
+		goto out_free_perm;
+	}
+
+	attr = kcalloc(count, sizeof(*attr), GFP_KERNEL);
+	if (!attr) {
+		pr_err("SYSPARAM: Failed to allocate memory for parameter "
+				"attributes\n");
+		goto out_free_perm;
+	}
+
+	/* For each of the parameters, populate the parameter attributes */
+	for (i = 0; i < count; i++) {
+		if (size[i] > MAX_PARAM_DATA_LEN) {
+			pr_warn("SYSPARAM: Not creating parameter %d as size "
+				"exceeds buffer length\n", i);
+			continue;
+		}
+
+		sysfs_attr_init(&attr[i].kobj_attr.attr);
+		attr[i].param_id = id[i];
+		attr[i].param_size = size[i];
+		if (of_property_read_string_index(sysparam, "param-name", i,
+				&attr[i].kobj_attr.attr.name))
+			continue;
+
+		/* If the parameter is read-only or read-write */
+		switch (perm[i] & 3) {
+		case OPAL_SYSPARAM_READ:
+			attr[i].kobj_attr.attr.mode = 0444;
+			break;
+		case OPAL_SYSPARAM_WRITE:
+			attr[i].kobj_attr.attr.mode = 0200;
+			break;
+		case OPAL_SYSPARAM_RW:
+			attr[i].kobj_attr.attr.mode = 0644;
+			break;
+		default:
+			break;
+		}
+
+		attr[i].kobj_attr.show = sys_param_show;
+		attr[i].kobj_attr.store = sys_param_store;
+
+		if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
+			pr_err("SYSPARAM: Failed to create sysfs file %s\n",
+					attr[i].kobj_attr.attr.name);
+			goto out_free_attr;
+		}
+	}
+
+	kfree(perm);
+	kfree(size);
+	kfree(id);
+	of_node_put(sysparam);
+	return;
+
+out_free_attr:
+	kfree(attr);
+out_free_perm:
+	kfree(perm);
+out_free_size:
+	kfree(size);
+out_free_id:
+	kfree(id);
+out_param_buf:
+	kfree(param_data_buf);
+out_kobj_put:
+	kobject_put(sysparam_kobj);
+out_node_put:
+	of_node_put(sysparam);
+out:
+	return;
+}