platform/x86/amd/pmf: Add support to update system state

PMF driver based on the output actions from the TA can request to update
the system states like entering s0i3, lock screen etc. by generating
an uevent. Based on the udev rules set in the userspace the event id
matching the uevent shall get updated accordingly using the systemctl.

Sample udev rules under Documentation/admin-guide/pmf.rst.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20231212014705.2017474-9-Shyam-sundar.S-k@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

2 files changed, 43 insertions, 0 deletions

diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
index 37bf1c701361..50f98c398727 100644
--- a/drivers/platform/x86/amd/pmf/pmf.h
+++ b/drivers/platform/x86/amd/pmf/pmf.h
@@ -73,6 +73,7 @@
 #define PMF_POLICY_STT_MIN					6
 #define PMF_POLICY_STT_SKINTEMP_APU				7
 #define PMF_POLICY_STT_SKINTEMP_HS2				8
+#define PMF_POLICY_SYSTEM_STATE					9
 #define PMF_POLICY_P3T						38
 
 /* TA macros */
@@ -445,6 +446,13 @@ enum smart_pc_status {
 };
 
 /* Smart PC - TA internals */
+enum system_state {
+	SYSTEM_STATE_S0i3,
+	SYSTEM_STATE_S4,
+	SYSTEM_STATE_SCREEN_LOCK,
+	SYSTEM_STATE_MAX,
+};
+
 enum ta_slider {
 	TA_BEST_BATTERY,
 	TA_BETTER_BATTERY,
@@ -476,6 +484,7 @@ enum ta_pmf_error_type {
 };
 
 struct pmf_action_table {
+	enum system_state system_state;
 	u32 spl;		/* in mW */
 	u32 sppt;		/* in mW */
 	u32 sppt_apuonly;	/* in mW */
diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
index bf8cb98d41ec..8811631c7be5 100644
--- a/drivers/platform/x86/amd/pmf/tee-if.c
+++ b/drivers/platform/x86/amd/pmf/tee-if.c
@@ -24,6 +24,20 @@ MODULE_PARM_DESC(pb_actions_ms, "Policy binary actions sampling frequency (defau
 static const uuid_t amd_pmf_ta_uuid = UUID_INIT(0x6fd93b77, 0x3fb8, 0x524d,
 						0xb1, 0x2d, 0xc5, 0x29, 0xb1, 0x3d, 0x85, 0x43);
 
+static const char *amd_pmf_uevent_as_str(unsigned int state)
+{
+	switch (state) {
+	case SYSTEM_STATE_S0i3:
+		return "S0i3";
+	case SYSTEM_STATE_S4:
+		return "S4";
+	case SYSTEM_STATE_SCREEN_LOCK:
+		return "SCREEN_LOCK";
+	default:
+		return "Unknown Smart PC event";
+	}
+}
+
 static void amd_pmf_prepare_args(struct amd_pmf_dev *dev, int cmd,
 				 struct tee_ioctl_invoke_arg *arg,
 				 struct tee_param *param)
@@ -42,6 +56,20 @@ static void amd_pmf_prepare_args(struct amd_pmf_dev *dev, int cmd,
 	param[0].u.memref.shm_offs = 0;
 }
 
+static int amd_pmf_update_uevents(struct amd_pmf_dev *dev, u16 event)
+{
+	char *envp[2] = {};
+
+	envp[0] = kasprintf(GFP_KERNEL, "EVENT_ID=%d", event);
+	if (!envp[0])
+		return -EINVAL;
+
+	kobject_uevent_env(&dev->dev->kobj, KOBJ_CHANGE, envp);
+
+	kfree(envp[0]);
+	return 0;
+}
+
 static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_result *out)
 {
 	u32 val;
@@ -113,6 +141,12 @@ static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_
 				dev->prev_data->p3t_limit = val;
 			}
 			break;
+
+		case PMF_POLICY_SYSTEM_STATE:
+			amd_pmf_update_uevents(dev, val);
+			dev_dbg(dev->dev, "update SYSTEM_STATE: %s\n",
+				amd_pmf_uevent_as_str(val));
+			break;
 		}
 	}
 }