On Wed, Jun 16, 2021 at 07:12:40PM +0530, Pratik R. Sampat wrote:
> Adds a generic interface to represent the energy and frequency related
> PAPR attributes on the system using the new H_CALL
> "H_GET_ENERGY_SCALE_INFO".
>
> H_GET_EM_PARMS H_CALL was previously responsible for exporting this
> information in the lparcfg, however the H_GET_EM_PARMS H_CALL
> will be deprecated P10 onwards.
>
> The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format:
> 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
> );
>
> This H_CALL can query either all the attributes at once with
> firstAttributeId = 0, flags = 0 as well as query only one attribute
> at a time with firstAttributeId = id
For a single attribute, the “firstAttributeId” must be set by the
caller to the attribute id to retrieve and the “singleAttribute” field
in “flags” must also be set to a 1.
If we don't set the "flags" to 1, while specifying a firstAttributeId,
the hypervisor will populate the buffer with the details pertaining to
all the attributes beginning with firstAttributeId.
>
> The output buffer consists of the following
> 1. number of attributes - 8 bytes
> 2. array offset to the data location - 8 bytes
> 3. version info - 1 byte
> 4. A data array of size num attributes, which contains the following:
> a. attribute ID - 8 bytes
> b. attribute value in number - 8 bytes
> c. attribute name in string - 64 bytes
> d. attribute value in string - 64 bytes
>
[..snip..]
> +
> +static ssize_t papr_show_value(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + char *buf)
> +{
> + struct papr_attr *pattr = container_of(attr, struct papr_attr, attr);
> + struct hv_energy_scale_buffer *t_buf;
> + struct energy_scale_attributes *t_ea;
> + int data_offset, ret = 0;
> +
> + t_buf = kmalloc(sizeof(*t_buf), GFP_KERNEL);
> + if (t_buf == NULL)
> + return -ENOMEM;
> +
> + ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0,
> + pattr->id, virt_to_phys(t_buf),
> + sizeof(*t_buf));
> +
In this case, since we are interested in only one attribute, we can
make the call
ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 1,
pattr->id, virt_to_phys(t_buf),
sizeof(*t_buf));
setting flags=1.
Same in the function papr_show_value_desc() below
--
Thanks and Regards
gautham.
> + if (ret != H_SUCCESS) {
> + pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
> + goto out;
> + }
> +
> + data_offset = be64_to_cpu(t_buf->array_offset) -
> + (sizeof(t_buf->num_attr) +
> + sizeof(t_buf->array_offset) +
> + sizeof(t_buf->data_header_version));
> +
> + t_ea = (struct energy_scale_attributes *) &t_buf->data[data_offset];
> +
> + ret = sprintf(buf, "%llu\n", be64_to_cpu(t_ea->attr_value));
> + if (ret < 0)
> + ret = -EIO;
> +out:
> + kfree(t_buf);
> +
> + return ret;
> +}
> +
> +static ssize_t papr_show_value_desc(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + char *buf)
> +{
> + struct papr_attr *pattr = container_of(attr, struct papr_attr, attr);
> + struct hv_energy_scale_buffer *t_buf;
> + struct energy_scale_attributes *t_ea;
> + int data_offset, ret = 0;
> +
> + t_buf = kmalloc(sizeof(*t_buf), GFP_KERNEL);
> + if (t_buf == NULL)
> + return -ENOMEM;
> +
> + ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0,
> + pattr->id, virt_to_phys(t_buf),
> + sizeof(*t_buf));
> +
> + if (ret != H_SUCCESS) {
> + pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
> + goto out;
> + }
> +
> + data_offset = be64_to_cpu(t_buf->array_offset) -
> + (sizeof(t_buf->num_attr) +
> + sizeof(t_buf->array_offset) +
> + sizeof(t_buf->data_header_version));
> +
> + t_ea = (struct energy_scale_attributes *) &t_buf->data[data_offset];
> +
> + ret = sprintf(buf, "%s\n", t_ea->attr_value_desc);
> + if (ret < 0)
> + ret = -EIO;
> +out:
> + kfree(t_buf);
> +
> + return ret;
> +}
> +
> +static struct papr_ops_info {
> + const char *attr_name;
> + ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
> + char *buf);
> +} ops_info[] = {
> + { "desc", papr_show_desc },
> + { "value", papr_show_value },
> + { "value_desc", papr_show_value_desc },
> +};
> +
> +static void add_attr(u64 id, int index, struct papr_attr *attr)
> +{
> + attr->id = id;
> + sysfs_attr_init(&attr->attr.attr);
> + attr->attr.attr.name = ops_info[index].attr_name;
> + attr->attr.attr.mode = 0444;
> + attr->attr.show = ops_info[index].show;
> +}
> +
> +static int add_attr_group(u64 id, int len, struct papr_group *pg,
> + bool show_val_desc)
> +{
> + int i;
> +
> + for (i = 0; i < len; 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].attr.attr;
> + }
> +
> + return sysfs_create_group(escale_kobj, &pg->pg);
> +}
> +
> +
> +static int __init papr_init(void)
> +{
> + uint64_t num_attr;
> + int ret, idx, i, data_offset;
> +
> + em_buf = kmalloc(sizeof(*em_buf), GFP_KERNEL);
> + if (em_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
> + */
> + ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0, 0,
> + virt_to_phys(em_buf), sizeof(*em_buf));
> +
> + if (!firmware_has_feature(FW_FEATURE_LPAR) || ret != H_SUCCESS ||
> + em_buf->data_header_version != 0x1) {
> + pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
> + goto out;
> + }
> +
> + num_attr = be64_to_cpu(em_buf->num_attr);
> +
> + /*
> + * Typecast the energy buffer to the attribute structure at the offset
> + * specified in the buffer
> + */
> + data_offset = be64_to_cpu(em_buf->array_offset) -
> + (sizeof(em_buf->num_attr) +
> + sizeof(em_buf->array_offset) +
> + sizeof(em_buf->data_header_version));
> +
> + ea = (struct energy_scale_attributes *) &em_buf->data[data_offset];
> +
> + pgs = kcalloc(num_attr, sizeof(*pgs), GFP_KERNEL);
> + if (!pgs)
> + goto out_pgs;
> +
> + papr_kobj = kobject_create_and_add("papr", firmware_kobj);
> + if (!papr_kobj) {
> + pr_warn("kobject_create_and_add papr failed\n");
> + goto out_kobj;
> + }
> +
> + escale_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
> + if (!escale_kobj) {
> + pr_warn("kobject_create_and_add energy_scale_info failed\n");
> + goto out_ekobj;
> + }
> +
> + for (idx = 0; idx < num_attr; idx++) {
> + char buf[4];
> + bool show_val_desc = true;
> +
> + pgs[idx].pgattrs = kcalloc(MAX_ATTRS,
> + sizeof(*pgs[idx].pgattrs),
> + GFP_KERNEL);
> + if (!pgs[idx].pgattrs)
> + goto out_kobj;
> +
> + pgs[idx].pg.attrs = kcalloc(MAX_ATTRS + 1,
> + sizeof(*pgs[idx].pg.attrs),
> + GFP_KERNEL);
> + if (!pgs[idx].pg.attrs) {
> + kfree(pgs[idx].pgattrs);
> + goto out_kobj;
> + }
> +
> + sprintf(buf, "%lld", be64_to_cpu(ea[idx].attr_id));
> + pgs[idx].pg.name = buf;
> +
> + /* Do not add the value description if it does not exist */
> + if (strlen(ea[idx].attr_value_desc) == 0)
> + show_val_desc = false;
> +
> + if (add_attr_group(be64_to_cpu(ea[idx].attr_id),
> + MAX_ATTRS, &pgs[idx], show_val_desc)) {
> + pr_warn("Failed to create papr attribute group %s\n",
> + pgs[idx].pg.name);
> + goto out_pgattrs;
> + }
> + }
> +
> + return 0;
> +
> +out_pgattrs:
> + for (i = 0; i < MAX_ATTRS; i++) {
> + kfree(pgs[i].pgattrs);
> + kfree(pgs[i].pg.attrs);
> + }
> +out_ekobj:
> + kobject_put(escale_kobj);
> +out_kobj:
> + kobject_put(papr_kobj);
> +out_pgs:
> + kfree(pgs);
> +out:
> + kfree(em_buf);
> +
> + return -ENOMEM;
> +}
> +
> +machine_device_initcall(pseries, papr_init);
> --
> 2.30.2
>
