[PATCH v8 20/23] firmware: arm_scmi: Add System Telemetry driver

[Cristian Marussi]

Add an SCMI driver to allow enumeration, configuration and data collection
of SCMI Telemetry data.

The driver exposes one character device for each found SCMI instance and a
set of related IOCTLs can be used to enumerate, configure and collect
Telemetry resources.

Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
v7 --> v8
 - Fixes for some Sashiko issues on v7
  - refactor batch handling into common batch init/fini routines
  - use array_size to check for overflows
  - explain cleanup logic of eventfd_ctx (xa_for_each)
  - add a mutex to protect events_xa
  - introduce per-IOCTL check on batch upper bounds
v6 --> v7
 - fixed module_init errors paths
 - introduced a check on FMODE to filter-out unprivleged writers
 - added  UUID list IOCTL
 - added UUID/SID/OFFS tp GET/SET config IOCTLs
 - added EVENT subscribe IOCTL
 - modified BATCH READ with per-DE status
 - added BATCHed mode for DE_CFG_SET/GET
 - fix setting properly discrete interval flag
 - new ABI feats flags\
 - new SCMI feats flags
 - new reserved checks
v5 --> v6
 - drop hunam readable .read capabilities on chardev
 - fill-up the new UAPI de_implementation version u8 array
 - added compat_ioctl support
 - fixed initialization of flags in scmi_tlm_to_uapi_base_info
 - fix grp_id bounds check in scmi_tlm_grp_info_get_ioctl
 - fix booleans
 - fix SHMTI get list to loop on input params
 - reworked bounds checks into:
   - scmi_tlm_intervals_get_ioctl
   - scmi_tlm_des_list_get_ioctl
   - scmi_tlm_grp_list_get_ioctl
   - scmi_tlm_grp_desc_get_ioctl
 - renamed some READ ioctl to be consistent
 - reject oversized mmap requests
 - support new GET_ABI_INFO IOCTL
 - support RESET IOCTL
 - add a missing READ_ONCE() to rinfo get
 - avoid gaps in the anon fds returned array needed by shmti mmap
 - adding missing cdev_del on remove
---
 drivers/firmware/arm_scmi/Kconfig             |   10 +
 drivers/firmware/arm_scmi/Makefile            |    1 +
 .../firmware/arm_scmi/scmi_system_telemetry.c | 1504 +++++++++++++++++
 3 files changed, 1515 insertions(+)
 create mode 100644 drivers/firmware/arm_scmi/scmi_system_telemetry.c

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index f506c4d1d96a..e7d8dd9fa907 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -113,4 +113,14 @@ config ARM_SCMI_POWER_CONTROL
 	  called scmi_power_control. Note this may be needed early in boot to
 	  catch early shutdown/reboot SCMI requests.
 
+config ARM_SCMI_SYSTEM_TELEMETRY
+	tristate "SCMI System Telemetry driver"
+	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
+	help
+	  This enables SCMI Systemn Telemetry support that allows userspace to
+	  retrieve ARM Telemetry data made available via SCMI.
+
+	  This driver can also be built as a module.  If so, the module will be
+	  called scmi_system_telemetry.
+
 endmenu
diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index fe55b7aa0707..20f8d55840a5 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-core.o
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o
 
 obj-$(CONFIG_ARM_SCMI_POWER_CONTROL) += scmi_power_control.o
+obj-$(CONFIG_ARM_SCMI_SYSTEM_TELEMETRY) += scmi_system_telemetry.o
diff --git a/drivers/firmware/arm_scmi/scmi_system_telemetry.c b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
new file mode 100644
index 000000000000..46933dc7b6ff
--- /dev/null
+++ b/drivers/firmware/arm_scmi/scmi_system_telemetry.c
@@ -0,0 +1,1504 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SCMI - System Telemetry Driver
+ *
+ * Copyright (C) 2026 ARM Ltd.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/atomic.h>
+#include <linux/ctype.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/scmi_protocol.h>
+#include <linux/slab.h>
+#include <linux/sprintf.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/uuid.h>
+#include <linux/wait.h>
+#include <linux/xarray.h>
+
+#include <uapi/linux/scmi.h>
+
+#define SCMI_TLM_DRIVER		"scmi-telemetry-driver"
+#define SCMI_TLM_NUM_DEVS	256
+
+#define MAX_BULK_LINE_CHAR_LENGTH		64
+
+/*
+ * Break if inadvertently struct scmi_telemetry_de_sample deviates from the
+ * UAPI counterpart struct scmi_tlm_de_sample: this allows more performant
+ * single DE reads.
+ */
+#define SCMI_DE_SAMPLE_BUILD_SANITY_CHECK				  \
+({									  \
+	BUILD_BUG_ON_MSG(sizeof(struct scmi_telemetry_de_sample) !=	  \
+			 sizeof(struct scmi_tlm_de_sample),		  \
+			 "UAPI DE sample mismatch !");			  \
+	ASSERT_STRUCT_OFFSET(struct scmi_telemetry_de_sample, id,	  \
+			     offsetof(struct scmi_tlm_de_sample, id));	  \
+	ASSERT_STRUCT_OFFSET(struct scmi_telemetry_de_sample, pad,	  \
+			     offsetof(struct scmi_tlm_de_sample, pad));	  \
+	ASSERT_STRUCT_OFFSET(struct scmi_telemetry_de_sample, tstamp,	  \
+			     offsetof(struct scmi_tlm_de_sample, tstamp));\
+	ASSERT_STRUCT_OFFSET(struct scmi_telemetry_de_sample, val,	  \
+			     offsetof(struct scmi_tlm_de_sample, val));	  \
+})
+
+static dev_t stlm_devt;
+
+/**
+ * struct scmi_tlm_setup  - Telemetry setup descriptor
+ * @dev: A reference to the related device
+ * @ph: A reference to the protocol handle to be used with the ops
+ * @rinfo: A reference to the resource info descriptor
+ * @ops: A reference to the protocol ops
+ */
+struct scmi_tlm_setup {
+	struct device *dev;
+	struct scmi_protocol_handle *ph;
+	const struct scmi_telemetry_res_info *rinfo;
+	const struct scmi_telemetry_proto_ops *ops;
+};
+
+/**
+ * struct scmi_tlm_instance  - Telemetry instance descriptor
+ * @id: Progressive number identifying this probed instance.
+ * @devt: The dev_t descriptor attached to this instance.
+ * @cdev: An embedded CDEV structure.
+ * @node: A node to link this in the list of all instances.
+ * @tsp: A reference to the SCMI instance data.
+ * @info: A reference to this instance SCMI Telemetry info data.
+ * @events_xa: An XArray holding Telemetry events currently subscribed by this
+ *	       instance of the driver.
+ * @events_mtx: A mutex to protect events_xa
+ */
+struct scmi_tlm_instance {
+	unsigned int id;
+	dev_t devt;
+	struct cdev cdev;
+	struct list_head node;
+	struct scmi_tlm_setup *tsp;
+	const struct scmi_telemetry_info *info;
+#define SCMI_TLM_EVT_XA_MIN	1
+#define scmi_evt_xa_limit	XA_LIMIT(SCMI_TLM_EVT_XA_MIN, UINT_MAX)
+	struct xarray events_xa;
+	/* Protect events_xa */
+	struct mutex events_mtx;
+};
+
+#define to_instance(c)	container_of(c, struct scmi_tlm_instance, cdev)
+
+struct scmi_tlm_shmti_ctx {
+	struct scmi_telemetry_shmti_info *shmti;
+	struct kref kref;
+};
+
+#define to_shmti_ctx(c)	container_of(c, struct scmi_tlm_shmti_ctx, kref)
+
+static inline void scmi_tlm_to_uapi_abi_info(struct scmi_tlm_abi_info *out,
+					     const struct scmi_telemetry_info *in)
+{
+	out->size = sizeof(*out);
+	out->abi_version = SCMI_TLM_CURRENT_ABI_VERSION;
+	out->abi_features = SCMI_TLM_ABI_FEAT_RESET | SCMI_TLM_ABI_FEAT_EVENT |
+		SCMI_TLM_ABI_FEAT_UUID_LIST | SCMI_TLM_ABI_FEAT_BATCH_STATE |
+		SCMI_TLM_ABI_FEAT_BATCHED_CFG | SCMI_TLM_ABI_FEAT_DE_TRACKING;
+	export_uuid(out->primary_de_impl_version, &in->base.primary_revision);
+	out->num_des = in->base.num_des;
+	out->num_groups = in->base.num_groups;
+	out->num_intervals = in->base.num_intervals;
+	out->num_shmtis = in->base.num_shmtis;
+	out->features = in->reset_support ? SCMI_TLM_SCMI_SUPPORT_RESET : 0;
+	out->features |= in->single_read_support ?
+		SCMI_TLM_SCMI_SUPPORT_SINGLE_SAMPLE : 0;
+	out->features |= in->per_group_config_support ?
+		SCMI_TLM_SCMI_SUPPORT_GROUP_CONFIG : 0;
+	out->features |= in->continuos_update_support ?
+		SCMI_TLM_SCMI_SUPPORT_UPDATE_NOTIFICATION : 0;
+}
+
+static inline void
+scmi_tlm_to_uapi_intervals(struct scmi_tlm_intervals *out,
+			   struct scmi_telemetry_intervals *in,
+			   struct scmi_tlm_update_interval *out_interv)
+{
+	unsigned int *in_interv = in->update_intervals;
+
+	out->flags |= in->discrete ? SCMI_TLM_INTERV_DISCRETE : 0;
+	out->num_intervals = 0;
+	for (int i = 0; i < in->num_intervals; i++) {
+		out_interv[i].secs =
+			SCMI_TLM_GET_UPDATE_INTERVAL_SECS(in_interv[i]);
+		out_interv[i].exp =
+			SCMI_TLM_GET_UPDATE_INTERVAL_EXP(in_interv[i]);
+
+		/* Count returned items */
+		out->num_intervals++;
+	}
+}
+
+static inline void scmi_tlm_to_uapi_de_info(struct scmi_tlm_de_info *out,
+					    struct scmi_telemetry_de_info *in)
+{
+	out->id = in->id;
+	out->grp_id = in->grp_id;
+	out->data_sz = in->data_sz;
+	out->type = in->type;
+	out->unit = in->unit;
+	out->unit_exp = in->unit_exp;
+	out->ts_rate = in->ts_rate;
+	out->instance_id = in->instance_id;
+	out->compo_instance_id = in->compo_instance_id;
+	out->compo_type = in->compo_type;
+	out->persistent = !!in->persistent;
+	out->flags = in->grp_id != SCMI_TLM_GRP_INVALID ?
+		SCMI_TLM_DEINFO_GROUP : 0;
+	out->pad[0] = 0;
+	out->pad[1] = 0;
+	out->pad2 = 0;
+	memcpy(out->name, in->name, 16);
+}
+
+static inline void
+scmi_tlm_to_uapi_des_list(struct scmi_tlm_des_list *out,
+			  const struct scmi_telemetry_res_info *in,
+			  struct scmi_tlm_de_info *des)
+{
+	out->num_des = 0;
+	for (int i = 0; i < in->num_des; i++) {
+		scmi_tlm_to_uapi_de_info(&des[i], &in->dei_store[i]);
+
+		/* Count returned items */
+		out->num_des++;
+	}
+}
+
+static inline void scmi_tlm_to_uapi_grp_info(struct scmi_tlm_grp_info *out,
+					     struct scmi_telemetry_grp_info *in)
+{
+	out->grp_id = in->grp_id;
+	out->num_des = in->num_des;
+	out->num_intervals = in->num_intervals;
+	out->pad = 0;
+}
+
+static inline void
+scmi_tlm_to_uapi_grps_list(struct scmi_tlm_grps_list *out,
+			   const struct scmi_telemetry_res_info *in,
+			   struct scmi_tlm_grp_info *ginfo)
+{
+	struct scmi_tlm_grp_info *out_ginfo = ginfo;
+
+	out->num_grps = 0;
+	for (int i = 0; i < in->num_groups; i++) {
+		scmi_tlm_to_uapi_grp_info(&out_ginfo[i], &in->grps_store[i]);
+
+		/* Count returned items */
+		out->num_grps++;
+	}
+}
+
+static inline void
+scmi_tlm_to_uapi_composing_des(struct scmi_tlm_grp_desc *out,
+			       const struct scmi_telemetry_res_info *in,
+			       u32 *composing_des)
+{
+	struct scmi_telemetry_grp_info *ginfo = &in->grps_store[out->grp_id];
+	struct scmi_telemetry_group *grp = &in->grps[out->grp_id];
+
+	out->num_des = 0;
+	for (int i = 0; i < ginfo->num_des; i++) {
+		composing_des[i] = in->des[grp->des[i]]->info->id;
+
+		/* Count returned items */
+		out->num_des++;
+	}
+}
+
+/**
+ * scmi_telemetry_res_info_get  - Resources info getter
+ * @tsp: A reference to the telemetry instance setup
+ *
+ * On first call this helper takes care to retrieve and cache all the resources
+ * descriptor from the platform, then, on the following invocations it will
+ * always return the cached value.
+ */
+static inline const struct scmi_telemetry_res_info *
+scmi_telemetry_res_info_get(struct scmi_tlm_setup *tsp)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+
+	if (READ_ONCE(tsp->rinfo))
+		return tsp->rinfo;
+
+	rinfo = tsp->ops->res_get(tsp->ph);
+	/* Cache the retrieved resource info value */
+	smp_store_mb(tsp->rinfo, rinfo);
+
+	return rinfo;
+}
+
+static long
+scmi_tlm_abi_info_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	struct scmi_tlm_abi_info base = {};
+	void __user *uptr = (void __user *)arg;
+	bool ignored_trailing;
+	u32 usize;
+	int err;
+
+	if (get_user(usize, (u32 __user *)arg))
+		return -EFAULT;
+
+	if (usize < offsetofend(struct scmi_tlm_abi_info, reserved))
+		return -EINVAL;
+
+	if (copy_struct_from_user(&base, sizeof(base), uptr, usize))
+		return -EFAULT;
+
+	if (base.reserved)
+		return -EINVAL;
+
+	scmi_tlm_to_uapi_abi_info(&base, ti->info);
+	err = copy_struct_to_user(uptr, usize, &base, sizeof(base),
+				  &ignored_trailing);
+	if (err)
+		return err;
+
+	if (ignored_trailing)
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static long
+scmi_tlm_config_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_config cfg;
+
+	if (copy_from_user(&cfg, uptr, sizeof(cfg)))
+		return -EFAULT;
+
+	if (cfg.pad || cfg.reserved || cfg.flags & ~SCMI_TLM_CONFIG_FLAGS)
+		return -EINVAL;
+
+	if (!(SCMI_TLM_CONFIG_IS_GROUP(cfg.flags))) {
+		unsigned int active = ti->info->active_update_interval;
+
+		cfg.enable = !!ti->info->enabled;
+		cfg.active.secs = SCMI_TLM_GET_UPDATE_INTERVAL_SECS(active);
+		cfg.active.exp = SCMI_TLM_GET_UPDATE_INTERVAL_EXP(active);
+	} else {
+		const struct scmi_telemetry_res_info *rinfo;
+		struct scmi_telemetry_group *grp;
+		unsigned int active;
+
+		rinfo = scmi_telemetry_res_info_get(ti->tsp);
+		if (cfg.grp_id >= rinfo->num_groups)
+			return -EINVAL;
+
+		grp = &rinfo->grps[cfg.grp_id];
+		active = grp->active_update_interval;
+
+		cfg.enable = grp->enabled;
+		cfg.t_enable = grp->tstamp_enabled;
+		cfg.active.secs = SCMI_TLM_GET_UPDATE_INTERVAL_SECS(active);
+		cfg.active.exp = SCMI_TLM_GET_UPDATE_INTERVAL_EXP(active);
+	}
+
+	if (copy_to_user(uptr, &cfg, sizeof(cfg)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_config_set_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_setup *tsp = ti->tsp;
+	struct scmi_tlm_config cfg;
+	unsigned int active;
+	bool ena, t_ena;
+
+	if (copy_from_user(&cfg, uptr, sizeof(cfg)))
+		return -EFAULT;
+
+	if (cfg.pad || cfg.reserved || cfg.flags & ~SCMI_TLM_CONFIG_FLAGS)
+		return -EINVAL;
+
+	ena = !!cfg.enable;
+	t_ena = !!cfg.t_enable;
+	if (!SCMI_TLM_CONFIG_IS_GROUP(cfg.flags)) {
+		cfg.grp_id = SCMI_TLM_GRP_INVALID;
+	} else {
+		int ret;
+
+		ret = tsp->ops->state_set(tsp->ph, true, cfg.grp_id, &ena, &t_ena,
+					  NULL, NULL, NULL);
+		if (ret)
+			return ret;
+	}
+
+	active = SCMI_TLM_BUILD_UPDATE_INTERVAL(cfg.active.secs, cfg.active.exp);
+
+	return tsp->ops->collection_configure(tsp->ph, cfg.grp_id, &ena, &active, NULL);
+}
+
+static long
+scmi_tlm_intervals_get_ioctl(const struct scmi_tlm_instance *ti,
+			     unsigned long arg)
+{
+	struct scmi_telemetry_intervals *tlm_ivs;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_intervals ivs;
+	size_t ivs_intrv_sz;
+
+	if (copy_from_user(&ivs, uptr, sizeof(ivs)))
+		return -EFAULT;
+
+	if (ivs.pad[0] || ivs.pad[1] || ivs.pad[2] || ivs.pad2 ||
+	    ivs.reserved || ivs.flags & ~SCMI_TLM_INTERV_FLAGS)
+		return -EINVAL;
+
+	if (!SCMI_TLM_INTERV_IS_GROUP(ivs.flags)) {
+		tlm_ivs = ti->info->intervals;
+	} else {
+		const struct scmi_telemetry_res_info *rinfo;
+
+		rinfo = scmi_telemetry_res_info_get(ti->tsp);
+		if (ivs.grp_id >= rinfo->num_groups)
+			return -EINVAL;
+
+		tlm_ivs = rinfo->grps[ivs.grp_id].intervals;
+	}
+
+	/* Reject only undersized buffers */
+	if (ivs.num_intervals < tlm_ivs->num_intervals)
+		return -ENOSPC;
+
+	ivs_intrv_sz = array_size(ivs.num_intervals,
+				  sizeof(struct scmi_tlm_update_interval));
+	if (ivs_intrv_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	struct scmi_tlm_update_interval *ivs_intrv __free(kfree) =
+		kzalloc(ivs_intrv_sz, GFP_KERNEL);
+	if (!ivs_intrv)
+		return -ENOMEM;
+
+	if (copy_from_user(ivs_intrv, u64_to_user_ptr(ivs.intervals),
+			   ivs_intrv_sz))
+		return -EFAULT;
+
+	/* Passing the array as a param avoids dancing with uptr->intervals */
+	scmi_tlm_to_uapi_intervals(&ivs, tlm_ivs, ivs_intrv);
+	if (copy_to_user(u64_to_user_ptr(ivs.intervals),
+			 (void *)ivs_intrv, ivs_intrv_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &ivs, sizeof(ivs)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int
+scmi_tlm_batch_initialize(void __user *uptr, struct scmi_tlm_batch *batch,
+			  size_t item_sz, unsigned int max_items,
+			  void **out_items, size_t *out_batch_sz,
+			  int **out_states, size_t *out_states_sz)
+{
+	size_t batch_sz;
+
+	if (copy_from_user(batch, uptr, sizeof(*batch)))
+		return -EFAULT;
+
+	if (batch->reserved || batch->item_sz != item_sz ||
+	    batch->num_items > max_items)
+		return -EINVAL;
+
+	batch_sz = array_size(batch->num_items, batch->item_sz);
+	if (batch_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	void *items __free(kfree) = kzalloc(batch_sz, GFP_KERNEL);
+	if (!items)
+		return -ENOMEM;
+
+	/* Read all the requested configs */
+	if (copy_from_user(items, u64_to_user_ptr(batch->items), batch_sz))
+		return -EFAULT;
+
+	/* Is per-read status required ? */
+	if (batch->states) {
+		size_t states_sz;
+
+		states_sz = array_size(batch->num_items, sizeof(int));
+		if (states_sz == SIZE_MAX)
+			return -EOVERFLOW;
+
+		int *states_arr __free(kfree) = kzalloc(states_sz, GFP_KERNEL);
+		if (!states_arr)
+			return -ENOMEM;
+
+		if (copy_from_user(states_arr, u64_to_user_ptr(batch->states),
+				   states_sz))
+			return -EFAULT;
+
+		*out_states = no_free_ptr(states_arr);
+		*out_states_sz = states_sz;
+	}
+
+	*out_items = no_free_ptr(items);
+	*out_batch_sz = batch_sz;
+
+	return 0;
+}
+
+static int
+scmi_tlm_batch_finalize(void __user *uptr, struct scmi_tlm_batch *batch,
+			void *items, int *states, size_t batch_sz,
+			size_t states_sz)
+{
+	if (copy_to_user(u64_to_user_ptr(batch->items), items, batch_sz))
+		return -EFAULT;
+
+	if (batch->states) {
+		if (copy_to_user(u64_to_user_ptr(batch->states),
+				 states, states_sz))
+			return -EFAULT;
+	}
+
+	if (copy_to_user(uptr, batch, sizeof(*batch)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_all_de_config_set_ioctl(const struct scmi_tlm_instance *ti,
+				 unsigned long arg)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_de_config tcfg = {};
+	bool ena, t_ena;
+	int ret;
+
+	if (copy_from_user(&tcfg, uptr, sizeof(tcfg)))
+		return -EFAULT;
+
+	if (tcfg.reserved)
+		return -EINVAL;
+
+	ena = !!tcfg.enable;
+	t_ena = !!tcfg.t_enable;
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	for (int i = 0; i < rinfo->num_des; i++) {
+		ret = ti->tsp->ops->state_set(ti->tsp->ph, false,
+					      rinfo->des[i]->info->id,
+					      &ena, &t_ena, NULL, NULL, NULL);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static long
+scmi_tlm_all_de_config_get_ioctl(const struct scmi_tlm_instance *ti,
+				 unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_de_config tcfg = {};
+	bool ena, t_ena;
+	int ret;
+
+	if (copy_from_user(&tcfg, uptr, sizeof(tcfg)))
+		return -EFAULT;
+
+	if (tcfg.reserved)
+		return -EINVAL;
+
+	ena = !!tcfg.enable;
+	t_ena = !!tcfg.t_enable;
+	ret = ti->tsp->ops->state_get(ti->tsp->ph, NULL, &ena, &t_ena,
+				      NULL, NULL, NULL);
+	if (ret)
+		return ret;
+
+	tcfg.enable = !!ena;
+	tcfg.t_enable = !!t_ena;
+	if (copy_to_user(uptr, &tcfg, sizeof(tcfg)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_de_config_set_ioctl(const struct scmi_tlm_instance *ti,
+			     unsigned long arg)
+{
+	struct scmi_tlm_de_config *tcfg __free(kfree) = NULL;
+	int ret, *states __free(kfree) = NULL;
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_batch batch = {};
+	size_t batch_sz, states_sz;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	ret = scmi_tlm_batch_initialize(uptr, &batch, sizeof(*tcfg),
+					rinfo->num_des, (void **)&tcfg, &batch_sz,
+					&states, &states_sz);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < batch.num_items; i++) {
+		unsigned int sid, offset;
+		bool ena, t_ena;
+		uuid_t uuid;
+		int ret;
+
+		ena = !!tcfg[i].enable;
+		t_ena = !!tcfg[i].t_enable;
+
+		ret = ti->tsp->ops->state_set(ti->tsp->ph, false,
+					      tcfg[i].id, &ena, &t_ena,
+					      &sid, &offset, &uuid);
+		if (ret) {
+			if (!states)
+				return ret;
+
+			states[i] = ret;
+			continue;
+		}
+
+		tcfg[i].sid = sid;
+		tcfg[i].offset = offset;
+		export_uuid(tcfg[i].uuid, &uuid);
+	}
+
+	return scmi_tlm_batch_finalize(uptr, &batch, tcfg, states, batch_sz,
+				       states_sz);
+}
+
+static long
+scmi_tlm_de_config_get_ioctl(const struct scmi_tlm_instance *ti,
+			     unsigned long arg)
+{
+	struct scmi_tlm_de_config *tcfg __free(kfree) = NULL;
+	int ret, *states __free(kfree) = NULL;
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_batch batch = {};
+	size_t batch_sz, states_sz;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	ret = scmi_tlm_batch_initialize(uptr, &batch, sizeof(*tcfg),
+					rinfo->num_des, (void **)&tcfg,
+					&batch_sz, &states, &states_sz);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < batch.num_items; i++) {
+		unsigned int sid, offset;
+		bool ena, t_ena;
+		uuid_t uuid;
+
+		ena = !!tcfg[i].enable;
+		t_ena = !!tcfg[i].t_enable;
+		ret = ti->tsp->ops->state_get(ti->tsp->ph, &tcfg[i].id,
+					      &ena, &t_ena, &sid, &offset, &uuid);
+
+		if (ret) {
+			if (!states)
+				return ret;
+
+			states[i] = ret;
+			continue;
+		}
+
+		tcfg[i].enable = ena;
+		tcfg[i].t_enable = t_ena;
+		tcfg[i].sid = sid;
+		tcfg[i].offset = offset;
+		export_uuid(tcfg[i].uuid, &uuid);
+	}
+
+	return scmi_tlm_batch_finalize(uptr, &batch, tcfg, states, batch_sz,
+				       states_sz);
+}
+
+static long
+scmi_tlm_de_info_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_setup *tsp = ti->tsp;
+	const struct scmi_telemetry_de *de;
+	struct scmi_tlm_de_info dei;
+
+	if (copy_from_user(&dei, uptr, sizeof(dei)))
+		return -EFAULT;
+
+	/* Flags does NOT make sense in the input param */
+	if (dei.pad[0] || dei.pad[1] || dei.flags || dei.reserved)
+		return -EINVAL;
+
+	de = tsp->ops->de_lookup(tsp->ph, dei.id);
+	if (!de)
+		return -EINVAL;
+
+	scmi_tlm_to_uapi_de_info(&dei, de->info);
+	if (copy_to_user(uptr, &dei, sizeof(dei)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_des_list_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_des_list dsl;
+	size_t dsl_des_sz;
+
+	if (copy_from_user(&dsl, uptr, sizeof(dsl)))
+		return -EFAULT;
+
+	if (dsl.pad)
+		return -EINVAL;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	/* Reject only undersized buffers */
+	if (dsl.num_des < rinfo->num_des)
+		return -ENOSPC;
+
+	dsl_des_sz = array_size(dsl.num_des, sizeof(struct scmi_tlm_de_info));
+	if (dsl_des_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	struct scmi_tlm_de_info *dsl_des __free(kfree) =
+		kzalloc(dsl_des_sz, GFP_KERNEL);
+	if (!dsl_des)
+		return -ENOMEM;
+
+	if (copy_from_user(dsl_des, u64_to_user_ptr(dsl.des), dsl_des_sz))
+		return -EFAULT;
+
+	/* Passing the array as a param avoids dancing with uptr->intervals */
+	scmi_tlm_to_uapi_des_list(&dsl, rinfo, dsl_des);
+	if (copy_to_user(u64_to_user_ptr(dsl.des), (void *)dsl_des, dsl_des_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &dsl, sizeof(dsl)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_de_value_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_setup *tsp = ti->tsp;
+	struct scmi_tlm_de_sample sample;
+	int ret;
+
+	SCMI_DE_SAMPLE_BUILD_SANITY_CHECK;
+
+	if (copy_from_user(&sample, uptr, sizeof(sample)))
+		return -EFAULT;
+
+	if (sample.pad)
+		return -EINVAL;
+
+	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_instance *ti, unsigned long arg)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_grp_info ginfo;
+
+	if (copy_from_user(&ginfo, uptr, sizeof(ginfo)))
+		return -EFAULT;
+
+	if (ginfo.pad || ginfo.reserved)
+		return -EINVAL;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	if (ginfo.grp_id >= rinfo->num_groups)
+		return -EINVAL;
+
+	scmi_tlm_to_uapi_grp_info(&ginfo, &rinfo->grps_store[ginfo.grp_id]);
+	if (copy_to_user(uptr, &ginfo, sizeof(ginfo)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_grp_desc_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_grp_desc gdesc;
+	size_t composing_sz;
+
+	if (copy_from_user(&gdesc, uptr, sizeof(gdesc)))
+		return -EFAULT;
+
+	if (gdesc.reserved)
+		return -EINVAL;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	if (gdesc.grp_id >= rinfo->num_groups)
+		return -EINVAL;
+
+	/* Reject only undersized buffers */
+	if (gdesc.num_des < rinfo->grps_store[gdesc.grp_id].num_des)
+		return -ENOSPC;
+
+	composing_sz = array_size(gdesc.num_des, sizeof(u32));
+	if (composing_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	u32 *composing_des __free(kfree) = kzalloc(composing_sz, GFP_KERNEL);
+	if (!composing_des)
+		return -ENOMEM;
+
+	if (copy_from_user(composing_des, u64_to_user_ptr(gdesc.composing_des),
+			   composing_sz))
+		return -EFAULT;
+
+	/* Passing the array as a param avoids dancing with uptr->intervals */
+	scmi_tlm_to_uapi_composing_des(&gdesc, rinfo, composing_des);
+	if (copy_to_user(u64_to_user_ptr(gdesc.composing_des), composing_des,
+			 composing_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &gdesc, sizeof(gdesc)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+scmi_tlm_grps_list_get_ioctl(const struct scmi_tlm_instance *ti, unsigned long arg)
+{
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_grps_list gsl;
+	size_t ginfo_sz;
+
+	if (copy_from_user(&gsl, uptr, sizeof(gsl)))
+		return -EFAULT;
+
+	if (gsl.pad)
+		return -EINVAL;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	/* Reject only undersized buffers */
+	if (gsl.num_grps < rinfo->num_groups)
+		return -ENOSPC;
+
+	ginfo_sz = array_size(gsl.num_grps, sizeof(struct scmi_tlm_grp_info));
+	if (ginfo_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	struct scmi_tlm_grp_info *ginfo __free(kfree) =
+		kzalloc(ginfo_sz, GFP_KERNEL);
+	if (!ginfo)
+		return -ENOMEM;
+
+	if (copy_from_user(ginfo, u64_to_user_ptr(gsl.grps), ginfo_sz))
+		return -EFAULT;
+
+	scmi_tlm_to_uapi_grps_list(&gsl, rinfo, ginfo);
+	if (copy_to_user(u64_to_user_ptr(gsl.grps), ginfo, ginfo_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &gsl, sizeof(gsl)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long scmi_tlm_des_read_ioctl(const struct scmi_tlm_instance *ti,
+				    unsigned long arg, bool single)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_setup *tsp = ti->tsp;
+	struct scmi_tlm_data_read bulk;
+	unsigned int grp_id;
+	int ret;
+
+	if (copy_from_user(&bulk, uptr, sizeof(bulk)))
+		return -EFAULT;
+
+	if (bulk.pad[0] || bulk.pad[1] || bulk.pad[2] || bulk.pad2 ||
+	    bulk.flags & ~SCMI_TLM_READ_FLAGS)
+		return -EINVAL;
+
+	if (!SCMI_TLM_READ_IS_GROUP(bulk.flags)) {
+		grp_id = SCMI_TLM_GRP_INVALID;
+	} else {
+		const struct scmi_telemetry_res_info *rinfo;
+
+		rinfo = scmi_telemetry_res_info_get(tsp);
+		if (bulk.grp_id >= rinfo->num_groups)
+			return -EINVAL;
+
+		grp_id = bulk.grp_id;
+	}
+
+	struct scmi_telemetry_de_sample *samples __free(kfree) =
+		kcalloc(bulk.num_samples, sizeof(*samples), GFP_KERNEL);
+	if (!samples)
+		return -ENOMEM;
+
+	if (!single)
+		ret = tsp->ops->des_bulk_read(tsp->ph, grp_id,
+					      &bulk.num_samples, samples);
+	else
+		ret = tsp->ops->des_sample_get(tsp->ph, grp_id,
+					       &bulk.num_samples, samples);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(u64_to_user_ptr(bulk.samples), samples,
+			 bulk.num_samples * sizeof(*samples)))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &bulk, sizeof(bulk)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long scmi_tlm_des_batch_read_ioctl(const struct scmi_tlm_instance *ti,
+					  unsigned long arg)
+{
+	struct scmi_telemetry_de_sample *samples __free(kfree) = NULL;
+	int ret, *states __free(kfree) = NULL;
+	const struct scmi_telemetry_res_info *rinfo;
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_batch batch = {};
+	size_t batch_sz, states_sz;
+
+	rinfo = scmi_telemetry_res_info_get(ti->tsp);
+	ret = scmi_tlm_batch_initialize(uptr, &batch, sizeof(*samples),
+					rinfo->num_des, (void **)&samples,
+					&batch_sz, &states, &states_sz);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < batch.num_items; i++) {
+		int ret;
+
+		ret = ti->tsp->ops->de_data_read(ti->tsp->ph, &samples[i]);
+		if (ret) {
+			if (!states)
+				return ret;
+
+			states[i] = ret;
+			continue;
+		}
+	}
+
+	return scmi_tlm_batch_finalize(uptr, &batch, samples, states, batch_sz,
+				       states_sz);
+}
+
+static struct scmi_tlm_shmti_ctx *
+scmi_tlm_shmti_ctx_alloc(struct scmi_telemetry_shmti_info *shmti)
+{
+	struct scmi_tlm_shmti_ctx *ctx;
+
+	ctx = kzalloc_obj(*ctx);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->shmti = shmti;
+	kref_init(&ctx->kref);
+
+	return ctx;
+}
+
+static void scmi_tlm_shmti_ctx_release(struct kref *kref)
+{
+	struct scmi_tlm_shmti_ctx *ctx = to_shmti_ctx(kref);
+
+	kfree(ctx);
+}
+
+static struct scmi_tlm_shmti_ctx *
+scmi_tlm_shmti_ctx_get(struct scmi_tlm_shmti_ctx *ctx)
+{
+	kref_get(&ctx->kref);
+
+	return ctx;
+}
+
+static void scmi_tlm_shmti_ctx_put(struct scmi_tlm_shmti_ctx *ctx)
+{
+	kref_put(&ctx->kref, scmi_tlm_shmti_ctx_release);
+}
+
+static void scmi_tlm_shmti_vma_open(struct vm_area_struct *vma)
+{
+	scmi_tlm_shmti_ctx_get(vma->vm_private_data);
+}
+
+static void scmi_tlm_shmti_vma_close(struct vm_area_struct *vma)
+{
+	scmi_tlm_shmti_ctx_put(vma->vm_private_data);
+}
+
+static const struct vm_operations_struct scmi_tlm_shmti_vm_ops = {
+	.open = scmi_tlm_shmti_vma_open,
+	.close = scmi_tlm_shmti_vma_close,
+};
+
+static int scmi_tlm_shmti_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct scmi_tlm_shmti_ctx *ctx = filp->private_data;
+	unsigned long npages, expect, needed, req = vma->vm_end - vma->vm_start;
+	phys_addr_t base;
+	size_t map_sz;
+	int ret;
+
+	if (vma->vm_flags & VM_WRITE)
+		return -EPERM;
+
+	if (req < ctx->shmti->len)
+		return -EINVAL;
+
+	/* Align & reject oversized requests */
+	base = ctx->shmti->phys & PAGE_MASK;
+	needed = ctx->shmti->len + ctx->shmti->offset;
+	expect = DIV_ROUND_UP(needed, PAGE_SIZE);
+	npages = req >> PAGE_SHIFT;
+	if (npages > expect)
+		return -EINVAL;
+
+	map_sz = PAGE_ALIGN(needed);
+	vma->vm_private_data = scmi_tlm_shmti_ctx_get(ctx);
+	vma->vm_ops = &scmi_tlm_shmti_vm_ops;
+	/* Set appropriate caching attributes */
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	/* Map physical address range into user space */
+	ret = vm_iomap_memory(vma, base, map_sz);
+	if (ret) {
+		scmi_tlm_shmti_ctx_put(ctx);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int scmi_tlm_shmti_release(struct inode *ino, struct file *filp)
+{
+	scmi_tlm_shmti_ctx_put(filp->private_data);
+
+	return 0;
+}
+
+static const struct file_operations scmi_tlm_shmti_fops = {
+	.owner = THIS_MODULE,
+	.mmap = scmi_tlm_shmti_mmap,
+	.release = scmi_tlm_shmti_release,
+};
+
+static void
+scmi_tlm_allocate_anon_fds(const struct scmi_tlm_instance *ti,
+			   struct scmi_tlm_shmtis_list *out,
+			   struct scmi_tlm_shmti_info *shinfo)
+{
+	const struct scmi_telemetry_info *info = ti->info;
+	struct device *dev = ti->tsp->dev;
+	int idx = 0;
+
+	out->num_shmtis = 0;
+	for (int i = 0; i < info->base.num_shmtis; i++) {
+		struct scmi_telemetry_shmti_info *shmti = info->shmtis[i];
+		struct scmi_tlm_shmti_ctx *ctx;
+		int fd;
+
+		ctx = scmi_tlm_shmti_ctx_alloc(shmti);
+		if (IS_ERR(ctx)) {
+			dev_err(dev, "Failed CTX_ALLOC on SID: %u\n", shmti->sid);
+			continue;
+		}
+
+		fd = anon_inode_getfd(SCMI_TLM_DRIVER, &scmi_tlm_shmti_fops, ctx,
+				      O_RDONLY | O_CLOEXEC);
+		if (fd < 0) {
+			scmi_tlm_shmti_ctx_put(ctx);
+			dev_err(dev, "Failed ANON INODE on SID: %u\n", shmti->sid);
+			continue;
+		}
+
+		shinfo[idx].sid = shmti->sid;
+		shinfo[idx].fd = fd;
+		shinfo[idx].len = shmti->len;
+		shinfo[idx].offset = shmti->offset;
+
+		/* Count returned items */
+		out->num_shmtis++;
+		idx++;
+	}
+}
+
+static long
+scmi_tlm_shmtis_list_get_ioctl(const struct scmi_tlm_instance *ti,
+			       unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_shmtis_list ssl;
+	size_t shinfo_sz;
+
+	if (copy_from_user(&ssl, uptr, sizeof(ssl)))
+		return -EFAULT;
+
+	if (ssl.pad)
+		return -EINVAL;
+
+	/* Reject only undersized buffers */
+	if (ssl.num_shmtis < ti->info->base.num_shmtis)
+		return -ENOSPC;
+
+	shinfo_sz = array_size(ssl.num_shmtis, sizeof(struct scmi_tlm_shmti_info));
+	if (shinfo_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	struct scmi_tlm_shmti_info *shinfo __free(kfree) =
+		kzalloc(shinfo_sz, GFP_KERNEL);
+	if (!shinfo)
+		return -ENOMEM;
+
+	if (copy_from_user(shinfo, u64_to_user_ptr(ssl.shmtis), shinfo_sz))
+		return -EFAULT;
+
+	scmi_tlm_allocate_anon_fds(ti, &ssl, shinfo);
+	if (copy_to_user(u64_to_user_ptr(ssl.shmtis), shinfo, shinfo_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &ssl, sizeof(ssl)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long scmi_tlm_reset_ioctl(const struct scmi_tlm_instance *ti,
+				 unsigned long arg)
+{
+	return ti->tsp->ops->reset(ti->tsp->ph);
+}
+
+static long
+scmi_tlm_uuid_list_get_ioctl(const struct scmi_tlm_instance *ti,
+			     unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_uuid_list udl;
+	size_t uuids_sz;
+
+	if (copy_from_user(&udl, uptr, sizeof(udl)))
+		return -EFAULT;
+
+	if (udl.pad)
+		return -EINVAL;
+
+	if (!udl.num_uuids) {
+		/* Return the effective number of populated UUIDs */
+		udl.num_uuids = ti->info->num_uuids;
+
+		if (copy_to_user(uptr, &udl, sizeof(udl)))
+			return -EFAULT;
+
+		return 0;
+	}
+
+	/* Check that the requested size is acceptable */
+	if (udl.num_uuids > ti->info->num_uuids)
+		return -ENOSPC;
+
+	uuids_sz = array_size(udl.num_uuids, sizeof(struct scmi_tlm_uuid));
+	if (uuids_sz == SIZE_MAX)
+		return -EOVERFLOW;
+
+	/* A local scratch buffer... */
+	struct scmi_tlm_uuid *uuids __free(kfree) = kzalloc(uuids_sz, GFP_KERNEL);
+	if (!uuids)
+		return -ENOMEM;
+
+	if (copy_from_user(uuids, u64_to_user_ptr(udl.uuids), uuids_sz))
+		return -EFAULT;
+
+	for (int j = 0; j < udl.num_uuids; j++)
+		export_uuid(uuids[j].bytes, ti->info->uuids[j]);
+
+	if (copy_to_user(u64_to_user_ptr(udl.uuids), uuids, uuids_sz))
+		return -EFAULT;
+
+	if (copy_to_user(uptr, &udl, sizeof(udl)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int scmi_tlm_event_subscribe(struct scmi_tlm_instance *ti,
+				    struct scmi_tlm_event *evt)
+{
+	struct eventfd_ctx *ctx;
+	u32 cookie;
+	int ret;
+
+	/* Registering */
+	ctx = eventfd_ctx_fdget(evt->efd);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	guard(mutex)(&ti->events_mtx);
+	ret = xa_alloc(&ti->events_xa, &cookie, ctx, scmi_evt_xa_limit,
+		       GFP_KERNEL);
+	if (ret) {
+		eventfd_ctx_put(ctx);
+		return ret;
+	}
+
+	ret = ti->tsp->ops->event_subscribe(ti->tsp->ph, evt->type, ctx);
+	if (ret) {
+		xa_erase(&ti->events_xa, cookie);
+		eventfd_ctx_put(ctx);
+		return ret;
+	}
+
+	evt->cookie = cookie;
+
+	return 0;
+}
+
+static void scmi_tlm_event_unsubscribe(struct scmi_tlm_instance *ti,
+				       struct scmi_tlm_event *evt)
+{
+	struct eventfd_ctx *ctx;
+
+	if (!evt->cookie)
+		return;
+
+	guard(mutex)(&ti->events_mtx);
+	ctx = xa_erase(&ti->events_xa, evt->cookie);
+	if (!ctx)
+		return;
+
+	ti->tsp->ops->event_unsubscribe(ti->tsp->ph, evt->type, ctx);
+
+	eventfd_ctx_put(ctx);
+}
+
+static long scmi_tlm_event_subscribe_ioctl(struct scmi_tlm_instance *ti,
+					   unsigned long arg)
+{
+	void __user *uptr = (void __user *)arg;
+	struct scmi_tlm_event evt = {};
+	int ret;
+
+	if (copy_from_user(&evt, uptr, sizeof(evt)))
+		return -EFAULT;
+
+	if (evt.pad || evt.reserved)
+		return -EINVAL;
+
+	/* Reject only undersized buffers */
+	if (evt.type > SCMI_TLM_EVT_LAST)
+		return -ENODEV;
+
+	if (!evt.cookie) {
+		/* Register new event, return new cookie */
+		ret = scmi_tlm_event_subscribe(ti, &evt);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(uptr, &evt, sizeof(evt))) {
+			scmi_tlm_event_unsubscribe(ti, &evt);
+			return -EFAULT;
+		}
+	} else {
+		/* DE-Register if existent, put context */
+		scmi_tlm_event_unsubscribe(ti, &evt);
+	}
+
+	return 0;
+}
+
+static long scmi_tlm_unlocked_ioctl(struct file *filp, unsigned int cmd,
+				    unsigned long arg)
+{
+	struct inode *ino = file_inode(filp);
+	struct scmi_tlm_instance *ti = to_instance(ino->i_cdev);
+	bool writable = filp->f_mode & FMODE_WRITE;
+
+	switch (cmd) {
+	case SCMI_TLM_GET_ABI_INFO:
+		return scmi_tlm_abi_info_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_CFG:
+		return scmi_tlm_config_get_ioctl(ti, arg);
+	case SCMI_TLM_SET_CFG:
+		if (writable)
+			return scmi_tlm_config_set_ioctl(ti, arg);
+		break;
+	case SCMI_TLM_GET_INTRVS:
+		return scmi_tlm_intervals_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_DE_CFG:
+		return scmi_tlm_de_config_get_ioctl(ti, arg);
+	case SCMI_TLM_SET_DE_CFG:
+		if (writable)
+			return scmi_tlm_de_config_set_ioctl(ti, arg);
+		break;
+	case SCMI_TLM_GET_DE_INFO:
+		return scmi_tlm_de_info_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_DE_LIST:
+		return scmi_tlm_des_list_get_ioctl(ti, arg);
+	case SCMI_TLM_DE_READ:
+		return scmi_tlm_de_value_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_ALL_CFG:
+		return scmi_tlm_all_de_config_get_ioctl(ti, arg);
+	case SCMI_TLM_SET_ALL_CFG:
+		if (writable)
+			return scmi_tlm_all_de_config_set_ioctl(ti, arg);
+		break;
+	case SCMI_TLM_GET_GRP_LIST:
+		return scmi_tlm_grps_list_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_GRP_INFO:
+		return scmi_tlm_grp_info_get_ioctl(ti, arg);
+	case SCMI_TLM_GET_GRP_DESC:
+		return scmi_tlm_grp_desc_get_ioctl(ti, arg);
+	case SCMI_TLM_SINGLE_READ:
+		return scmi_tlm_des_read_ioctl(ti, arg, true);
+	case SCMI_TLM_BULK_READ:
+		return scmi_tlm_des_read_ioctl(ti, arg, false);
+	case SCMI_TLM_BATCH_READ:
+		return scmi_tlm_des_batch_read_ioctl(ti, arg);
+	case SCMI_TLM_GET_SHMTI_LIST:
+		return scmi_tlm_shmtis_list_get_ioctl(ti, arg);
+	case SCMI_TLM_RESET:
+		if (writable)
+			return scmi_tlm_reset_ioctl(ti, arg);
+		break;
+	case SCMI_TLM_GET_UUID_LIST:
+		return scmi_tlm_uuid_list_get_ioctl(ti, arg);
+	case SCMI_TLM_EVENT_SUBSCRIBE:
+		return scmi_tlm_event_subscribe_ioctl(ti, arg);
+	default:
+		return -ENOTTY;
+	}
+
+	return -EPERM;
+}
+
+static const struct file_operations stlm_fops = {
+	.owner = THIS_MODULE,
+	.open = nonseekable_open,
+	.unlocked_ioctl = scmi_tlm_unlocked_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+};
+
+static struct scmi_tlm_instance *scmi_tlm_init(struct scmi_tlm_setup *tsp,
+					       unsigned int instance_id)
+{
+	struct device *dev = tsp->dev;
+	struct scmi_tlm_instance *ti;
+
+	ti = devm_kzalloc(dev, sizeof(*ti), GFP_KERNEL);
+	if (!ti)
+		return ERR_PTR(-ENOMEM);
+
+	ti->info = tsp->ops->info_get(tsp->ph);
+	if (!ti->info)
+		return dev_err_ptr_probe(dev,
+					 -EINVAL, "invalid Telemetry info !\n");
+
+	ti->id = instance_id;
+	ti->tsp = tsp;
+	xa_init_flags(&ti->events_xa, XA_FLAGS_ALLOC);
+	mutex_init(&ti->events_mtx);
+
+	return ti;
+}
+
+static char *scmi_tlm_devnode(const struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "scmi/%s", dev_name(dev));
+}
+
+static struct class stlm_class = {
+	.name    = "stlm",
+	.devnode = scmi_tlm_devnode,
+};
+
+static int scmi_telemetry_probe(struct scmi_device *sdev)
+{
+	const struct scmi_handle *handle = sdev->handle;
+	struct device *tdev, *dev = &sdev->dev;
+	struct scmi_protocol_handle *ph;
+	struct scmi_tlm_instance *ti;
+	struct scmi_tlm_setup *tsp;
+	unsigned int instance;
+	const void *ops;
+	int ret;
+
+	if (!handle)
+		return -ENODEV;
+
+	ops = handle->devm_protocol_get(sdev, sdev->protocol_id, &ph);
+	if (IS_ERR(ops))
+		return dev_err_probe(dev, PTR_ERR(ops),
+				     "Cannot access protocol:0x%X\n",
+				     sdev->protocol_id);
+
+	tsp = devm_kzalloc(dev, sizeof(*tsp), GFP_KERNEL);
+	if (!tsp)
+		return -ENOMEM;
+
+	tsp->dev = dev;
+	tsp->ops = ops;
+	tsp->ph = ph;
+
+	instance = handle->id;
+	if (instance >= SCMI_TLM_NUM_DEVS)
+		return -ENOSPC;
+
+	ti = scmi_tlm_init(tsp, instance);
+	if (IS_ERR(ti))
+		return PTR_ERR(ti);
+
+	cdev_init(&ti->cdev, &stlm_fops);
+	ti->cdev.owner = THIS_MODULE;
+	ti->devt = MKDEV(MAJOR(stlm_devt), MINOR(stlm_devt) + instance);
+	ret = cdev_add(&ti->cdev, ti->devt, 1);
+	if (ret)
+		return ret;
+
+	tdev = device_create(&stlm_class, NULL, ti->devt, ti, "tlm_%d", ti->id);
+	if (IS_ERR(tdev)) {
+		cdev_del(&ti->cdev);
+		return  PTR_ERR(tdev);
+	}
+
+	dev_set_drvdata(&sdev->dev, ti);
+
+	return 0;
+}
+
+static void scmi_telemetry_remove(struct scmi_device *sdev)
+{
+	struct scmi_tlm_instance *ti;
+	struct eventfd_ctx *ctx;
+	unsigned long cookie = SCMI_TLM_EVT_XA_MIN;
+
+	ti = dev_get_drvdata(&sdev->dev);
+	if (!ti)
+		return;
+
+	/*
+	 * Any STILL subscribed event is cleaned-up here on remove NOT on
+	 * frop.release so that a process could subscribe for an event providing
+	 * its eventfd and then close the tlm_<N> and just monitoring the
+	 * events.
+	 * */
+	guard(mutex)(&ti->events_mtx);
+	xa_for_each(&ti->events_xa, cookie, ctx) {
+		xa_erase(&ti->events_xa, cookie);
+		ti->tsp->ops->event_unsubscribe(ti->tsp->ph,
+						SCMI_TLM_EVT_GENERATION, ctx);
+		eventfd_ctx_put(ctx);
+	}
+	xa_destroy(&ti->events_xa);
+
+	device_destroy(&stlm_class, ti->devt);
+	cdev_del(&ti->cdev);
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+	{ SCMI_PROTOCOL_TELEMETRY, "telemetry" },
+	{ }
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static struct scmi_driver scmi_telemetry_driver = {
+	.name = SCMI_TLM_DRIVER,
+	.probe = scmi_telemetry_probe,
+	.remove = scmi_telemetry_remove,
+	.id_table = scmi_id_table,
+};
+
+static int __init scmi_telemetry_init(void)
+{
+	int ret;
+
+	ret = alloc_chrdev_region(&stlm_devt, 0, SCMI_TLM_NUM_DEVS,
+				  SCMI_TLM_DRIVER);
+	if (ret)
+		return ret;
+
+	ret = class_register(&stlm_class);
+	if (ret)
+		goto err_class;
+
+	ret = scmi_register(&scmi_telemetry_driver);
+	if (ret)
+		goto err_scmi;
+
+	return 0;
+
+err_scmi:
+	class_unregister(&stlm_class);
+
+err_class:
+	unregister_chrdev_region(stlm_devt, SCMI_TLM_NUM_DEVS);
+
+	return ret;
+}
+module_init(scmi_telemetry_init);
+
+static void __exit scmi_telemetry_exit(void)
+{
+	scmi_unregister(&scmi_telemetry_driver);
+	unregister_chrdev_region(stlm_devt, SCMI_TLM_NUM_DEVS);
+	class_unregister(&stlm_class);
+}
+module_exit(scmi_telemetry_exit);
+
+MODULE_AUTHOR("Cristian Marussi <cristian.marussi@xxxxxxx>");
+MODULE_DESCRIPTION("ARM SCMI Telemetry Driver");
+MODULE_LICENSE("GPL");
-- 
2.54.0