[PATCH v2 10/17] firmware: arm_scmi: Add System Telemetry ioctls support
Cristian Marussi
cristian.marussi at arm.com
Wed Jan 14 03:46:14 PST 2026
Extend the filesystem based interface with special 'control' files that can
be used to configure and retrieve SCMI Telemetry data in binary form using
the ioctls-based ABI described in uapi/linux/scmi.h.
This alternative ABI is meant to provide a more performant access to SCMI
Telemetry configuration and data events, without the hassle of navigating
the human readable VFS based intwerface.
Signed-off-by: Cristian Marussi <cristian.marussi at arm.com>
---
v1 --> v2
- Use new res_get() operation which use new resource accessors
- Use new de_lookup() tlm_ops
- Using cleanup.h
---
.../firmware/arm_scmi/scmi_system_telemetry.c | 404 ++++++++++++++++++
1 file changed, 404 insertions(+)
diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
index b48f2d4eecae..721de615bec3 100644
--- a/drivers/firmware/arm_scmi/scmi_system_telemetry.c
+++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
@@ -24,6 +24,8 @@
#include <linux/string.h>
#include <linux/uaccess.h>
+#include <uapi/linux/scmi.h>
+
#define TLM_FS_MAGIC 0x75C01C80
#define TLM_FS_NAME "stlmfs"
#define TLM_FS_MNT "arm_telemetry"
@@ -1056,6 +1058,406 @@ DEFINE_TLM_CLASS(grp_available_interval_tlmo, "available_update_intervals_ms",
DEFINE_TLM_CLASS(grp_intervals_discrete_tlmo, "intervals_discrete",
TLM_IS_GROUP, S_IFREG | S_IRUSR, &intrv_discrete_fops, NULL);
+static long
+scmi_tlm_info_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ const struct scmi_telemetry_info *info = tlmi->priv;
+ void * __user uptr = (void * __user)arg;
+
+ if (copy_to_user(uptr, &info->base, sizeof(info->base)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_intervals_get_ioctl(const struct scmi_tlm_inode *tlmi,
+ unsigned long arg, bool is_group)
+{
+ struct scmi_tlm_intervals ivs, *tlm_ivs;
+ void * __user uptr = (void * __user)arg;
+
+ if (copy_from_user(&ivs, uptr, sizeof(ivs)))
+ return -EFAULT;
+
+ if (!is_group) {
+ const struct scmi_telemetry_info *info = tlmi->priv;
+
+ tlm_ivs = info->intervals;
+ } else {
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+
+ tlm_ivs = grp->intervals;
+ }
+
+ if (ivs.num != tlm_ivs->num)
+ return -EINVAL;
+
+ if (copy_to_user(uptr, tlm_ivs,
+ sizeof(*tlm_ivs) + sizeof(u32) * ivs.num))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_de_config_set_ioctl(const struct scmi_tlm_inode *tlmi,
+ unsigned long arg, bool all)
+{
+ const struct scmi_telemetry_res_info *rinfo;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ struct scmi_tlm_de_config tcfg = {};
+ int ret;
+
+ if (copy_from_user(&tcfg, uptr, sizeof(tcfg)))
+ return -EFAULT;
+
+ if (!all)
+ return tsp->ops->state_set(tsp->ph, false, tcfg.id,
+ (bool *)&tcfg.enable,
+ (bool *)&tcfg.t_enable);
+
+ rinfo = scmi_telemetry_res_info_get(tsp);
+ for (int i = 0; i < rinfo->num_des; i++) {
+ ret = tsp->ops->state_set(tsp->ph, false,
+ rinfo->des[i]->info->id,
+ (bool *)&tcfg.enable,
+ (bool *)&tcfg.t_enable);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static long
+scmi_tlm_de_config_get_ioctl(const struct scmi_tlm_inode *tlmi,
+ unsigned long arg)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_de_config tcfg = {};
+ int ret;
+
+ if (copy_from_user(&tcfg, uptr, sizeof(tcfg)))
+ return -EFAULT;
+
+ ret = tsp->ops->state_get(tsp->ph, tcfg.id,
+ (bool *)&tcfg.enable, (bool *)&tcfg.t_enable);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(uptr, &tcfg, sizeof(tcfg)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_config_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg,
+ bool is_group)
+{
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_config cfg;
+
+ if (!is_group) {
+ const struct scmi_telemetry_info *info = tlmi->priv;
+
+ cfg.enable = !!info->enabled;
+ cfg.current_update_interval = info->active_update_interval;
+ } else {
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+
+ cfg.enable = !!grp->enabled;
+ cfg.t_enable = !!grp->tstamp_enabled;
+ cfg.current_update_interval = grp->active_update_interval;
+ }
+
+ if (copy_to_user(uptr, &cfg, sizeof(cfg)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_config_set_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg,
+ bool is_group)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_config cfg = {};
+ bool grp_ignore;
+ int res_id;
+
+ if (copy_from_user(&cfg, uptr, sizeof(cfg)))
+ return -EFAULT;
+
+ if (!is_group) {
+ res_id = SCMI_TLM_GRP_INVALID;
+ grp_ignore = true;
+ } else {
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+ int ret;
+
+ res_id = grp->info->id;
+ grp_ignore = false;
+ ret = tsp->ops->state_set(tsp->ph, true, res_id,
+ (bool *)&cfg.enable,
+ (bool *)&cfg.t_enable);
+ if (ret)
+ return ret;
+ }
+
+ return tsp->ops->collection_configure(tsp->ph, res_id, grp_ignore,
+ (bool *)&cfg.enable,
+ &cfg.current_update_interval,
+ NULL);
+}
+
+static long
+scmi_tlm_de_info_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ void * __user uptr = (void * __user)arg;
+ const struct scmi_telemetry_de *de;
+ struct scmi_tlm_de_info dei;
+
+ if (copy_from_user(&dei, uptr, sizeof(dei)))
+ return -EFAULT;
+
+ de = tsp->ops->de_lookup(tsp->ph, dei.id);
+ if (!de)
+ return -EINVAL;
+
+ if (copy_to_user(uptr, de->info, sizeof(*de->info)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_des_list_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ const struct scmi_telemetry_res_info *rinfo;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_des_list dsl;
+
+ rinfo = scmi_telemetry_res_info_get(tsp);
+ if (copy_from_user(&dsl, uptr, sizeof(dsl)))
+ return -EFAULT;
+
+ if (dsl.num_des < rinfo->num_des)
+ return -EINVAL;
+
+ if (copy_to_user(uptr, &rinfo->num_des, sizeof(rinfo->num_des)))
+ return -EFAULT;
+
+ if (copy_to_user(uptr + sizeof(rinfo->num_des), rinfo->dei_store,
+ rinfo->num_des * sizeof(*rinfo->dei_store)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_de_value_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_de_sample sample;
+ int ret;
+
+ if (copy_from_user(&sample, uptr, sizeof(sample)))
+ return -EFAULT;
+
+ ret = tsp->ops->de_data_read(tsp->ph,
+ (struct scmi_telemetry_de_sample *)&sample);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(uptr, &sample, sizeof(sample)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_grp_info_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+ void * __user uptr = (void * __user)arg;
+
+ if (copy_to_user(uptr, grp->info, sizeof(*grp->info)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_grp_desc_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+ unsigned int num_des = grp->info->num_des;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_grp_desc grp_desc;
+
+ if (copy_from_user(&grp_desc, uptr, sizeof(grp_desc)))
+ return -EFAULT;
+
+ if (grp_desc.num_des < num_des)
+ return -EINVAL;
+
+ if (copy_to_user(uptr, &num_des, sizeof(num_des)))
+ return -EFAULT;
+
+ if (copy_to_user(uptr + sizeof(num_des), grp->des,
+ sizeof(*grp->des) * num_des))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long
+scmi_tlm_grps_list_get_ioctl(const struct scmi_tlm_inode *tlmi, unsigned long arg)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ const struct scmi_telemetry_res_info *rinfo;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_grps_list gsl;
+
+ if (copy_from_user(&gsl, uptr, sizeof(gsl)))
+ return -EFAULT;
+
+ rinfo = scmi_telemetry_res_info_get(tsp);
+ if (gsl.num_grps < rinfo->num_groups)
+ return -EINVAL;
+
+ if (copy_to_user(uptr, &rinfo->num_groups, sizeof(rinfo->num_groups)))
+ return -EFAULT;
+
+ if (copy_to_user(uptr + sizeof(rinfo->num_groups), rinfo->grps_store,
+ rinfo->num_groups * sizeof(*rinfo->grps_store)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long scmi_tlm_des_read_ioctl(const struct scmi_tlm_inode *tlmi,
+ unsigned long arg, bool single,
+ bool is_group)
+{
+ struct scmi_tlm_setup *tsp = tlmi->tsp;
+ void * __user uptr = (void * __user)arg;
+ struct scmi_tlm_data_read bulk;
+ int ret, grp_id = SCMI_TLM_GRP_INVALID;
+
+ if (copy_from_user(&bulk, uptr, sizeof(bulk)))
+ return -EFAULT;
+
+ struct scmi_tlm_data_read *bulk_ptr __free(kfree) =
+ kzalloc(struct_size(bulk_ptr, samples, bulk.num_samples),
+ GFP_KERNEL);
+ if (!bulk_ptr)
+ return -ENOMEM;
+
+ if (is_group) {
+ const struct scmi_telemetry_group *grp = tlmi->priv;
+
+ grp_id = grp->info->id;
+ }
+
+ bulk_ptr->num_samples = bulk.num_samples;
+ if (!single)
+ ret = tsp->ops->des_bulk_read(tsp->ph, grp_id,
+ &bulk_ptr->num_samples,
+ (struct scmi_telemetry_de_sample *)bulk_ptr->samples);
+ else
+ ret = tsp->ops->des_sample_get(tsp->ph, grp_id,
+ &bulk_ptr->num_samples,
+ (struct scmi_telemetry_de_sample *)bulk_ptr->samples);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(uptr, bulk_ptr, sizeof(*bulk_ptr) +
+ bulk_ptr->num_samples * sizeof(bulk_ptr->samples[0])))
+ return -EFAULT;
+
+ return 0;
+}
+
+static long scmi_tlm_unlocked_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct scmi_tlm_inode *tlmi = to_tlm_inode(file_inode(filp));
+ bool is_group = IS_GROUP(tlmi->cls->flags);
+
+ switch (cmd) {
+ case SCMI_TLM_GET_INFO:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_info_get_ioctl(tlmi, arg);
+ case SCMI_TLM_GET_CFG:
+ return scmi_tlm_config_get_ioctl(tlmi, arg, is_group);
+ case SCMI_TLM_SET_CFG:
+ return scmi_tlm_config_set_ioctl(tlmi, arg, is_group);
+ case SCMI_TLM_GET_INTRVS:
+ return scmi_tlm_intervals_get_ioctl(tlmi, arg, is_group);
+ case SCMI_TLM_GET_DE_CFG:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_de_config_get_ioctl(tlmi, arg);
+ case SCMI_TLM_SET_DE_CFG:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_de_config_set_ioctl(tlmi, arg, false);
+ case SCMI_TLM_GET_DE_INFO:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_de_info_get_ioctl(tlmi, arg);
+ case SCMI_TLM_GET_DE_LIST:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_des_list_get_ioctl(tlmi, arg);
+ case SCMI_TLM_GET_DE_VALUE:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_de_value_get_ioctl(tlmi, arg);
+ case SCMI_TLM_SET_ALL_CFG:
+ return scmi_tlm_de_config_set_ioctl(tlmi, arg, true);
+ case SCMI_TLM_GET_GRP_LIST:
+ if (is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_grps_list_get_ioctl(tlmi, arg);
+ case SCMI_TLM_GET_GRP_INFO:
+ if (!is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_grp_info_get_ioctl(tlmi, arg);
+ case SCMI_TLM_GET_GRP_DESC:
+ if (!is_group)
+ return -EOPNOTSUPP;
+ return scmi_tlm_grp_desc_get_ioctl(tlmi, arg);
+ case SCMI_TLM_SINGLE_SAMPLE:
+ return scmi_tlm_des_read_ioctl(tlmi, arg, true, is_group);
+ case SCMI_TLM_BULK_READ:
+ return scmi_tlm_des_read_ioctl(tlmi, arg, false, is_group);
+ default:
+ return -ENOTTY;
+ }
+}
+
+static const struct file_operations scmi_tlm_ctrl_fops = {
+ .owner = THIS_MODULE,
+ .open = nonseekable_open,
+ .unlocked_ioctl = scmi_tlm_unlocked_ioctl,
+};
+
+DEFINE_TLM_CLASS(ctrl_tlmo, "control", 0,
+ S_IFREG | S_IRUSR | S_IWUSR, &scmi_tlm_ctrl_fops, NULL);
+DEFINE_TLM_CLASS(grp_ctrl_tlmo, "control", TLM_IS_GROUP,
+ S_IFREG | S_IRUSR | S_IWUSR, &scmi_tlm_ctrl_fops, NULL);
+
static int scmi_telemetry_groups_initialize(struct scmi_tlm_instance *ti)
{
const struct scmi_telemetry_res_info *rinfo;
@@ -1095,6 +1497,7 @@ static int scmi_telemetry_groups_initialize(struct scmi_tlm_instance *ti)
stlmfs_create_dentry(sb, tsp, grp_dir_dentry,
&grp_composing_des_tlmo, grp->des_str);
+ stlmfs_create_dentry(sb, tsp, grp_dir_dentry, &grp_ctrl_tlmo, grp);
stlmfs_create_dentry(sb, tsp, grp_dir_dentry, &grp_data_tlmo, grp);
stlmfs_create_dentry(sb, tsp, grp_dir_dentry,
&grp_single_sample_tlmo, grp);
@@ -1279,6 +1682,7 @@ static int scmi_tlm_root_dentries_initialize(struct scmi_tlm_instance *ti)
&ti->info->base.version);
stlmfs_create_dentry(sb, tsp, ti->top_dentry, &data_tlmo, ti->info);
stlmfs_create_dentry(sb, tsp, ti->top_dentry, &single_sample_tlmo, ti->info);
+ stlmfs_create_dentry(sb, tsp, ti->top_dentry, &ctrl_tlmo, ti->info);
ti->des_dentry =
stlmfs_create_dentry(sb, tsp, ti->top_dentry, &des_dir_cls, NULL);
ti->grps_dentry =
--
2.52.0
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