arch/powerpc/platforms/pseries/papr_platform_attributes.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Platform energy and frequency attributes driver
  *
  * This driver creates a sys file at /sys/firmware/papr/ which encapsulates a
  * directory structure containing files in keyword - value pairs that specify
  * energy and frequency configuration of the system.
  *
  * The format of exposing the sysfs information is as follows:
  * /sys/firmware/papr/energy_scale_info/
  *  |-- <id>/
  *    |-- desc
  *    |-- value
  *    |-- value_desc (if exists)
  *  |-- <id>/
  *    |-- desc
  *    |-- value
  *    |-- value_desc (if exists)
  *
  * Copyright 2022 IBM Corp.
  */

 #include <asm/hvcall.h>
 #include <asm/machdep.h>
 #include <asm/firmware.h>

 #include "pseries.h"

 /*
  * Flag attributes to fetch either all or one attribute from the HCALL
  * flag = BE(0) => fetch all attributes with firstAttributeId = 0
  * flag = BE(1) => fetch a single attribute with firstAttributeId = id
  */
 #define ESI_FLAGS_ALL		0
 #define ESI_FLAGS_SINGLE	(1ull << 63)

 #define KOBJ_MAX_ATTRS		3

 #define ESI_HDR_SIZE		sizeof(struct h_energy_scale_info_hdr)
 #define ESI_ATTR_SIZE		sizeof(struct energy_scale_attribute)
 #define CURR_MAX_ESI_ATTRS	8

 struct energy_scale_attribute {
 	__be64 id;
 	__be64 val;
 	u8 desc[64];
 	u8 value_desc[64];
 } __packed;

 struct h_energy_scale_info_hdr {
 	__be64 num_attrs;
 	__be64 array_offset;
 	u8 data_header_version;
 } __packed;

 struct papr_attr {
 	u64 id;
 	struct kobj_attribute kobj_attr;
 };

 struct papr_group {
 	struct attribute_group pg;
 	struct papr_attr pgattrs[KOBJ_MAX_ATTRS];
 };

 static struct papr_group *papr_groups;
 /* /sys/firmware/papr */
 static struct kobject *papr_kobj;
 /* /sys/firmware/papr/energy_scale_info */
 static struct kobject *esi_kobj;

 /*
  * Energy modes can change dynamically hence making a new hcall each time the
  * information needs to be retrieved
  */
 static int papr_get_attr(u64 id, struct energy_scale_attribute *esi)
 {
 	int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
 	int ret, max_esi_attrs = CURR_MAX_ESI_ATTRS;
 	struct energy_scale_attribute *curr_esi;
 	struct h_energy_scale_info_hdr *hdr;
 	char *buf;

 	buf = kmalloc(esi_buf_size, GFP_KERNEL);
 	if (buf == NULL)
 		return -ENOMEM;

 retry:
 	ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_SINGLE,
 				 id, virt_to_phys(buf),
 				 esi_buf_size);

 	/*
 	 * If the hcall fails with not enough memory for either the
 	 * header or data, attempt to allocate more
 	 */
 	if (ret == H_PARTIAL || ret == H_P4) {
 		char *temp_buf;

 		max_esi_attrs += 4;
 		esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);

 		temp_buf = krealloc(buf, esi_buf_size, GFP_KERNEL);
 		if (temp_buf)
 			buf = temp_buf;
 		else
 			return -ENOMEM;

 		goto retry;
 	}

 	if (ret != H_SUCCESS) {
 		pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
 		ret = -EIO;
 		goto out_buf;
 	}

 	hdr = (struct h_energy_scale_info_hdr *) buf;
 	curr_esi = (struct energy_scale_attribute *)
 		(buf + be64_to_cpu(hdr->array_offset));

 	if (esi_buf_size <
 	    be64_to_cpu(hdr->array_offset) + (be64_to_cpu(hdr->num_attrs)
 	    * sizeof(struct energy_scale_attribute))) {
 		ret = -EIO;
 		goto out_buf;
 	}

 	*esi = *curr_esi;

 out_buf:
 	kfree(buf);

 	return ret;
 }

 /*
  * Extract and export the description of the energy scale attributes
  */
 static ssize_t desc_show(struct kobject *kobj,
 			  struct kobj_attribute *kobj_attr,
 			  char *buf)
 {
 	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
 					       kobj_attr);
 	struct energy_scale_attribute esi;
 	int ret;

 	ret = papr_get_attr(pattr->id, &esi);
 	if (ret)
 		return ret;

 	return sysfs_emit(buf, "%s\n", esi.desc);
 }

 /*
  * Extract and export the numeric value of the energy scale attributes
  */
 static ssize_t val_show(struct kobject *kobj,
 			 struct kobj_attribute *kobj_attr,
 			 char *buf)
 {
 	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
 					       kobj_attr);
 	struct energy_scale_attribute esi;
 	int ret;

 	ret = papr_get_attr(pattr->id, &esi);
 	if (ret)
 		return ret;

 	return sysfs_emit(buf, "%llu\n", be64_to_cpu(esi.val));
 }

 /*
  * Extract and export the value description in string format of the energy
  * scale attributes
  */
 static ssize_t val_desc_show(struct kobject *kobj,
 			      struct kobj_attribute *kobj_attr,
 			      char *buf)
 {
 	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
 					       kobj_attr);
 	struct energy_scale_attribute esi;
 	int ret;

 	ret = papr_get_attr(pattr->id, &esi);
 	if (ret)
 		return ret;

 	return sysfs_emit(buf, "%s\n", esi.value_desc);
 }

 static struct papr_ops_info {
 	const char *attr_name;
 	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *kobj_attr,
 			char *buf);
 } ops_info[KOBJ_MAX_ATTRS] = {
 	{ "desc", desc_show },
 	{ "value", val_show },
 	{ "value_desc", val_desc_show },
 };

 static void add_attr(u64 id, int index, struct papr_attr *attr)
 {
 	attr->id = id;
 	sysfs_attr_init(&attr->kobj_attr.attr);
 	attr->kobj_attr.attr.name = ops_info[index].attr_name;
 	attr->kobj_attr.attr.mode = 0444;
 	attr->kobj_attr.show = ops_info[index].show;
 }

 static int add_attr_group(u64 id, struct papr_group *pg, bool show_val_desc)
 {
 	int i;

 	for (i = 0; i < KOBJ_MAX_ATTRS; i++) {
 		if (!strcmp(ops_info[i].attr_name, "value_desc") &&
 		    !show_val_desc) {
 			continue;
 		}
 		add_attr(id, i, &pg->pgattrs[i]);
 		pg->pg.attrs[i] = &pg->pgattrs[i].kobj_attr.attr;
 	}

 	return sysfs_create_group(esi_kobj, &pg->pg);
 }


 static int __init papr_init(void)
 {
 	int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
 	int ret, idx, i, max_esi_attrs = CURR_MAX_ESI_ATTRS;
 	struct h_energy_scale_info_hdr *esi_hdr;
 	struct energy_scale_attribute *esi_attrs;
 	uint64_t num_attrs;
 	char *esi_buf;

 	if (!firmware_has_feature(FW_FEATURE_LPAR) ||
 	    !firmware_has_feature(FW_FEATURE_ENERGY_SCALE_INFO)) {
 		return -ENXIO;
 	}

 	esi_buf = kmalloc(esi_buf_size, GFP_KERNEL);
 	if (esi_buf == NULL)
 		return -ENOMEM;
 	/*
 	 * hcall(
 	 * uint64 H_GET_ENERGY_SCALE_INFO,  // Get energy scale info
 	 * uint64 flags,            // Per the flag request
 	 * uint64 firstAttributeId, // The attribute id
 	 * uint64 bufferAddress,    // Guest physical address of the output buffer
 	 * uint64 bufferSize);      // The size in bytes of the output buffer
 	 */
 retry:

 	ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_ALL, 0,
 				 virt_to_phys(esi_buf), esi_buf_size);

 	/*
 	 * If the hcall fails with not enough memory for either the
 	 * header or data, attempt to allocate more
 	 */
 	if (ret == H_PARTIAL || ret == H_P4) {
 		char *temp_esi_buf;

 		max_esi_attrs += 4;
 		esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);

 		temp_esi_buf = krealloc(esi_buf, esi_buf_size, GFP_KERNEL);
 		if (temp_esi_buf)
 			esi_buf = temp_esi_buf;
 		else
 			return -ENOMEM;

 		goto retry;
 	}

 	if (ret != H_SUCCESS) {
 		pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO, ret: %d\n", ret);
 		goto out_free_esi_buf;
 	}

 	esi_hdr = (struct h_energy_scale_info_hdr *) esi_buf;
 	num_attrs = be64_to_cpu(esi_hdr->num_attrs);
 	esi_attrs = (struct energy_scale_attribute *)
 		    (esi_buf + be64_to_cpu(esi_hdr->array_offset));

 	if (esi_buf_size <
 	    be64_to_cpu(esi_hdr->array_offset) +
 	    (num_attrs * sizeof(struct energy_scale_attribute))) {
 		goto out_free_esi_buf;
 	}

 	papr_groups = kcalloc(num_attrs, sizeof(*papr_groups), GFP_KERNEL);
 	if (!papr_groups)
 		goto out_free_esi_buf;

 	papr_kobj = kobject_create_and_add("papr", firmware_kobj);
 	if (!papr_kobj) {
 		pr_warn("kobject_create_and_add papr failed\n");
 		goto out_papr_groups;
 	}

 	esi_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
 	if (!esi_kobj) {
 		pr_warn("kobject_create_and_add energy_scale_info failed\n");
 		goto out_kobj;
 	}

 	/* Allocate the groups before registering */
 	for (idx = 0; idx < num_attrs; idx++) {
 		papr_groups[idx].pg.attrs = kcalloc(KOBJ_MAX_ATTRS + 1,
 					    sizeof(*papr_groups[idx].pg.attrs),
 					    GFP_KERNEL);
 		if (!papr_groups[idx].pg.attrs)
 			goto out_pgattrs;

 		papr_groups[idx].pg.name = kasprintf(GFP_KERNEL, "%lld",
 					     be64_to_cpu(esi_attrs[idx].id));
 		if (papr_groups[idx].pg.name == NULL)
 			goto out_pgattrs;
 	}

 	for (idx = 0; idx < num_attrs; idx++) {
 		bool show_val_desc = true;

 		/* Do not add the value desc attr if it does not exist */
 		if (strnlen(esi_attrs[idx].value_desc,
 			    sizeof(esi_attrs[idx].value_desc)) == 0)
 			show_val_desc = false;

 		if (add_attr_group(be64_to_cpu(esi_attrs[idx].id),
 				   &papr_groups[idx],
 				   show_val_desc)) {
 			pr_warn("Failed to create papr attribute group %s\n",
 				papr_groups[idx].pg.name);
 			idx = num_attrs;
 			goto out_pgattrs;
 		}
 	}

 	kfree(esi_buf);
 	return 0;
 out_pgattrs:
 	for (i = 0; i < idx ; i++) {
 		kfree(papr_groups[i].pg.attrs);
 		kfree(papr_groups[i].pg.name);
 	}
 	kobject_put(esi_kobj);
 out_kobj:
 	kobject_put(papr_kobj);
 out_papr_groups:
 	kfree(papr_groups);
 out_free_esi_buf:
 	kfree(esi_buf);

 	return -ENOMEM;
 }

 machine_device_initcall(pseries, papr_init);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Platform energy and frequency attributes driver
	*
	* This driver creates a sys file at /sys/firmware/papr/ which encapsulates a
	* directory structure containing files in keyword - value pairs that specify
	* energy and frequency configuration of the system.
	*
	* The format of exposing the sysfs information is as follows:
	* /sys/firmware/papr/energy_scale_info/
	* \|-- <id>/
	* \|-- desc
	* \|-- value
	* \|-- value_desc (if exists)
	* \|-- <id>/
	* \|-- desc
	* \|-- value
	* \|-- value_desc (if exists)
	*
	* Copyright 2022 IBM Corp.
	*/

	#include <asm/hvcall.h>
	#include <asm/machdep.h>
	#include <asm/firmware.h>

	#include "pseries.h"

	/*
	* Flag attributes to fetch either all or one attribute from the HCALL
	* flag = BE(0) => fetch all attributes with firstAttributeId = 0
	* flag = BE(1) => fetch a single attribute with firstAttributeId = id
	*/
	#define ESI_FLAGS_ALL 0
	#define ESI_FLAGS_SINGLE (1ull << 63)

	#define KOBJ_MAX_ATTRS 3

	#define ESI_HDR_SIZE sizeof(struct h_energy_scale_info_hdr)
	#define ESI_ATTR_SIZE sizeof(struct energy_scale_attribute)
	#define CURR_MAX_ESI_ATTRS 8

	struct energy_scale_attribute {
	__be64 id;
	__be64 val;
	u8 desc[64];
	u8 value_desc[64];
	} __packed;

	struct h_energy_scale_info_hdr {
	__be64 num_attrs;
	__be64 array_offset;
	u8 data_header_version;
	} __packed;

	struct papr_attr {
	u64 id;
	struct kobj_attribute kobj_attr;
	};

	struct papr_group {
	struct attribute_group pg;
	struct papr_attr pgattrs[KOBJ_MAX_ATTRS];
	};

	static struct papr_group *papr_groups;
	/* /sys/firmware/papr */
	static struct kobject *papr_kobj;
	/* /sys/firmware/papr/energy_scale_info */
	static struct kobject *esi_kobj;

	/*
	* Energy modes can change dynamically hence making a new hcall each time the
	* information needs to be retrieved
	*/
	static int papr_get_attr(u64 id, struct energy_scale_attribute *esi)
	{
	int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
	int ret, max_esi_attrs = CURR_MAX_ESI_ATTRS;
	struct energy_scale_attribute *curr_esi;
	struct h_energy_scale_info_hdr *hdr;
	char *buf;

	buf = kmalloc(esi_buf_size, GFP_KERNEL);
	if (buf == NULL)
	return -ENOMEM;

	retry:
	ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_SINGLE,
	id, virt_to_phys(buf),
	esi_buf_size);

	/*
	* If the hcall fails with not enough memory for either the
	* header or data, attempt to allocate more
	*/
	if (ret == H_PARTIAL \|\| ret == H_P4) {
	char *temp_buf;

	max_esi_attrs += 4;
	esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);

	temp_buf = krealloc(buf, esi_buf_size, GFP_KERNEL);
	if (temp_buf)
	buf = temp_buf;
	else
	return -ENOMEM;

	goto retry;
	}

	if (ret != H_SUCCESS) {
	pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
	ret = -EIO;
	goto out_buf;
	}

	hdr = (struct h_energy_scale_info_hdr *) buf;
	curr_esi = (struct energy_scale_attribute *)
	(buf + be64_to_cpu(hdr->array_offset));

	if (esi_buf_size <
	be64_to_cpu(hdr->array_offset) + (be64_to_cpu(hdr->num_attrs)
	* sizeof(struct energy_scale_attribute))) {
	ret = -EIO;
	goto out_buf;
	}

	esi = curr_esi;

	out_buf:
	kfree(buf);

	return ret;
	}

	/*
	* Extract and export the description of the energy scale attributes
	*/
	static ssize_t desc_show(struct kobject *kobj,
	struct kobj_attribute *kobj_attr,
	char *buf)
	{
	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
	kobj_attr);
	struct energy_scale_attribute esi;
	int ret;

	ret = papr_get_attr(pattr->id, &esi);
	if (ret)
	return ret;

	return sysfs_emit(buf, "%s\n", esi.desc);
	}

	/*
	* Extract and export the numeric value of the energy scale attributes
	*/
	static ssize_t val_show(struct kobject *kobj,
	struct kobj_attribute *kobj_attr,
	char *buf)
	{
	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
	kobj_attr);
	struct energy_scale_attribute esi;
	int ret;

	ret = papr_get_attr(pattr->id, &esi);
	if (ret)
	return ret;

	return sysfs_emit(buf, "%llu\n", be64_to_cpu(esi.val));
	}

	/*
	* Extract and export the value description in string format of the energy
	* scale attributes
	*/
	static ssize_t val_desc_show(struct kobject *kobj,
	struct kobj_attribute *kobj_attr,
	char *buf)
	{
	struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
	kobj_attr);
	struct energy_scale_attribute esi;
	int ret;

	ret = papr_get_attr(pattr->id, &esi);
	if (ret)
	return ret;

	return sysfs_emit(buf, "%s\n", esi.value_desc);
	}

	static struct papr_ops_info {
	const char *attr_name;
	ssize_t (show)(struct kobject kobj, struct kobj_attribute *kobj_attr,
	char *buf);
	} ops_info[KOBJ_MAX_ATTRS] = {
	{ "desc", desc_show },
	{ "value", val_show },
	{ "value_desc", val_desc_show },
	};

	static void add_attr(u64 id, int index, struct papr_attr *attr)
	{
	attr->id = id;
	sysfs_attr_init(&attr->kobj_attr.attr);
	attr->kobj_attr.attr.name = ops_info[index].attr_name;
	attr->kobj_attr.attr.mode = 0444;
	attr->kobj_attr.show = ops_info[index].show;
	}

	static int add_attr_group(u64 id, struct papr_group *pg, bool show_val_desc)
	{
	int i;

	for (i = 0; i < KOBJ_MAX_ATTRS; i++) {
	if (!strcmp(ops_info[i].attr_name, "value_desc") &&
	!show_val_desc) {
	continue;
	}
	add_attr(id, i, &pg->pgattrs[i]);
	pg->pg.attrs[i] = &pg->pgattrs[i].kobj_attr.attr;
	}

	return sysfs_create_group(esi_kobj, &pg->pg);
	}


	static int __init papr_init(void)
	{
	int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
	int ret, idx, i, max_esi_attrs = CURR_MAX_ESI_ATTRS;
	struct h_energy_scale_info_hdr *esi_hdr;
	struct energy_scale_attribute *esi_attrs;
	uint64_t num_attrs;
	char *esi_buf;

	if (!firmware_has_feature(FW_FEATURE_LPAR) \|\|
	!firmware_has_feature(FW_FEATURE_ENERGY_SCALE_INFO)) {
	return -ENXIO;
	}

	esi_buf = kmalloc(esi_buf_size, GFP_KERNEL);
	if (esi_buf == NULL)
	return -ENOMEM;
	/*
	* hcall(
	* uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
	* uint64 flags, // Per the flag request
	* uint64 firstAttributeId, // The attribute id
	* uint64 bufferAddress, // Guest physical address of the output buffer
	* uint64 bufferSize); // The size in bytes of the output buffer
	*/
	retry:

	ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_ALL, 0,
	virt_to_phys(esi_buf), esi_buf_size);

	/*
	* If the hcall fails with not enough memory for either the
	* header or data, attempt to allocate more
	*/
	if (ret == H_PARTIAL \|\| ret == H_P4) {
	char *temp_esi_buf;

	max_esi_attrs += 4;
	esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);

	temp_esi_buf = krealloc(esi_buf, esi_buf_size, GFP_KERNEL);
	if (temp_esi_buf)
	esi_buf = temp_esi_buf;
	else
	return -ENOMEM;

	goto retry;
	}

	if (ret != H_SUCCESS) {
	pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO, ret: %d\n", ret);
	goto out_free_esi_buf;
	}

	esi_hdr = (struct h_energy_scale_info_hdr *) esi_buf;
	num_attrs = be64_to_cpu(esi_hdr->num_attrs);
	esi_attrs = (struct energy_scale_attribute *)
	(esi_buf + be64_to_cpu(esi_hdr->array_offset));

	if (esi_buf_size <
	be64_to_cpu(esi_hdr->array_offset) +
	(num_attrs * sizeof(struct energy_scale_attribute))) {
	goto out_free_esi_buf;
	}

	papr_groups = kcalloc(num_attrs, sizeof(*papr_groups), GFP_KERNEL);
	if (!papr_groups)
	goto out_free_esi_buf;

	papr_kobj = kobject_create_and_add("papr", firmware_kobj);
	if (!papr_kobj) {
	pr_warn("kobject_create_and_add papr failed\n");
	goto out_papr_groups;
	}

	esi_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
	if (!esi_kobj) {
	pr_warn("kobject_create_and_add energy_scale_info failed\n");
	goto out_kobj;
	}

	/* Allocate the groups before registering */
	for (idx = 0; idx < num_attrs; idx++) {
	papr_groups[idx].pg.attrs = kcalloc(KOBJ_MAX_ATTRS + 1,
	sizeof(*papr_groups[idx].pg.attrs),
	GFP_KERNEL);
	if (!papr_groups[idx].pg.attrs)
	goto out_pgattrs;

	papr_groups[idx].pg.name = kasprintf(GFP_KERNEL, "%lld",
	be64_to_cpu(esi_attrs[idx].id));
	if (papr_groups[idx].pg.name == NULL)
	goto out_pgattrs;
	}

	for (idx = 0; idx < num_attrs; idx++) {
	bool show_val_desc = true;

	/* Do not add the value desc attr if it does not exist */
	if (strnlen(esi_attrs[idx].value_desc,
	sizeof(esi_attrs[idx].value_desc)) == 0)
	show_val_desc = false;

	if (add_attr_group(be64_to_cpu(esi_attrs[idx].id),
	&papr_groups[idx],
	show_val_desc)) {
	pr_warn("Failed to create papr attribute group %s\n",
	papr_groups[idx].pg.name);
	idx = num_attrs;
	goto out_pgattrs;
	}
	}

	kfree(esi_buf);
	return 0;
	out_pgattrs:
	for (i = 0; i < idx ; i++) {
	kfree(papr_groups[i].pg.attrs);
	kfree(papr_groups[i].pg.name);
	}
	kobject_put(esi_kobj);
	out_kobj:
	kobject_put(papr_kobj);
	out_papr_groups:
	kfree(papr_groups);
	out_free_esi_buf:
	kfree(esi_buf);

	return -ENOMEM;
	}

	machine_device_initcall(pseries, papr_init);