platform/x86/amd/pmf: Add support for PMF Policy Binary

PMF Policy binary is a encrypted and signed binary that will be part
of the BIOS. PMF driver via the ACPI interface checks the existence
of Smart PC bit. If the advertised bit is found, PMF driver walks
the acpi namespace to find out the policy binary size and the address
which has to be passed to the TA during the TA init sequence.

The policy binary is comprised of inputs (or the events) and outputs
(or the actions). With the PMF ecosystem, OEMs generate the policy
binary (or could be multiple binaries) that contains a supported set
of inputs and outputs which could be specifically carved out for each
usage segment (or for each user also) that could influence the system
behavior either by enriching the user experience or/and boost/throttle
power limits.

Once the TA init command succeeds, the PMF driver sends the changing
events in the current environment to the TA for a constant sampling
frequency time (the event here could be a lid close or open) and
if the policy binary has corresponding action built within it, the
TA sends the action for it in the subsequent enact command.

If the inputs sent to the TA has no output defined in the policy
binary generated by OEMs, there will be no action to be performed
by the PMF driver.

Example policies:

1) if slider is performance ; set the SPL to 40W
Here PMF driver registers with the platform profile interface and
when the slider position is changed, PMF driver lets the TA know
about this. TA sends back an action to update the Sustained
Power Limit (SPL). PMF driver updates this limit via the PMFW mailbox.

2) if user_away ; then lock the system
Here PMF driver hooks to the AMD SFH driver to know the user presence
and send the inputs to TA and if the condition is met, the TA sends
the action of locking the system. PMF driver generates a uevent and
based on the udev rule in the userland the system gets locked with
systemctl.

The intent here is to provide the OEM's to make a policy to lock the
system when the user is away ; but the userland can make a choice to
ignore it.

The OEMs will have an utility to create numerous such policies and
the policies shall be reviewed by AMD before signing and encrypting
them. Policies are shared between operating systems to have seemless user
experience.

Since all this action has to happen via the "amdtee" driver, currently
there is no caller for it in the kernel which can load the amdtee driver.
Without amdtee driver loading onto the system the "tee" calls shall fail
from the PMF driver. Hence an explicit MODULE_SOFTDEP has been added
to address this.

Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20231212014705.2017474-5-Shyam-sundar.S-k@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 156 insertions, 2 deletions

diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
index 4036f435f1e2..f99dc79ebb40 100644
--- a/drivers/platform/x86/amd/pmf/tee-if.c
+++ b/drivers/platform/x86/amd/pmf/tee-if.c
@@ -42,9 +42,77 @@ static void amd_pmf_prepare_args(struct amd_pmf_dev *dev, int cmd,
 	param[0].u.memref.shm_offs = 0;
 }
 
+static void amd_pmf_apply_policies(struct amd_pmf_dev *dev, struct ta_pmf_enact_result *out)
+{
+	u32 val;
+	int idx;
+
+	for (idx = 0; idx < out->actions_count; idx++) {
+		val = out->actions_list[idx].value;
+		switch (out->actions_list[idx].action_index) {
+		case PMF_POLICY_SPL:
+			if (dev->prev_data->spl != val) {
+				amd_pmf_send_cmd(dev, SET_SPL, false, val, NULL);
+				dev_dbg(dev->dev, "update SPL: %u\n", val);
+				dev->prev_data->spl = val;
+			}
+			break;
+
+		case PMF_POLICY_SPPT:
+			if (dev->prev_data->sppt != val) {
+				amd_pmf_send_cmd(dev, SET_SPPT, false, val, NULL);
+				dev_dbg(dev->dev, "update SPPT: %u\n", val);
+				dev->prev_data->sppt = val;
+			}
+			break;
+
+		case PMF_POLICY_FPPT:
+			if (dev->prev_data->fppt != val) {
+				amd_pmf_send_cmd(dev, SET_FPPT, false, val, NULL);
+				dev_dbg(dev->dev, "update FPPT: %u\n", val);
+				dev->prev_data->fppt = val;
+			}
+			break;
+
+		case PMF_POLICY_SPPT_APU_ONLY:
+			if (dev->prev_data->sppt_apuonly != val) {
+				amd_pmf_send_cmd(dev, SET_SPPT_APU_ONLY, false, val, NULL);
+				dev_dbg(dev->dev, "update SPPT_APU_ONLY: %u\n", val);
+				dev->prev_data->sppt_apuonly = val;
+			}
+			break;
+
+		case PMF_POLICY_STT_MIN:
+			if (dev->prev_data->stt_minlimit != val) {
+				amd_pmf_send_cmd(dev, SET_STT_MIN_LIMIT, false, val, NULL);
+				dev_dbg(dev->dev, "update STT_MIN: %u\n", val);
+				dev->prev_data->stt_minlimit = val;
+			}
+			break;
+
+		case PMF_POLICY_STT_SKINTEMP_APU:
+			if (dev->prev_data->stt_skintemp_apu != val) {
+				amd_pmf_send_cmd(dev, SET_STT_LIMIT_APU, false, val, NULL);
+				dev_dbg(dev->dev, "update STT_SKINTEMP_APU: %u\n", val);
+				dev->prev_data->stt_skintemp_apu = val;
+			}
+			break;
+
+		case PMF_POLICY_STT_SKINTEMP_HS2:
+			if (dev->prev_data->stt_skintemp_hs2 != val) {
+				amd_pmf_send_cmd(dev, SET_STT_LIMIT_HS2, false, val, NULL);
+				dev_dbg(dev->dev, "update STT_SKINTEMP_HS2: %u\n", val);
+				dev->prev_data->stt_skintemp_hs2 = val;
+			}
+			break;
+		}
+	}
+}
+
 static int amd_pmf_invoke_cmd_enact(struct amd_pmf_dev *dev)
 {
 	struct ta_pmf_shared_memory *ta_sm = NULL;
+	struct ta_pmf_enact_result *out = NULL;
 	struct tee_param param[MAX_TEE_PARAM];
 	struct tee_ioctl_invoke_arg arg;
 	int ret = 0;
@@ -52,7 +120,10 @@ static int amd_pmf_invoke_cmd_enact(struct amd_pmf_dev *dev)
 	if (!dev->tee_ctx)
 		return -ENODEV;
 
+	memset(dev->shbuf, 0, dev->policy_sz);
 	ta_sm = dev->shbuf;
+	out = &ta_sm->pmf_output.policy_apply_table;
+
 	memset(ta_sm, 0, sizeof(*ta_sm));
 	ta_sm->command_id = TA_PMF_COMMAND_POLICY_BUILDER_ENACT_POLICIES;
 	ta_sm->if_version = PMF_TA_IF_VERSION_MAJOR;
@@ -65,6 +136,12 @@ static int amd_pmf_invoke_cmd_enact(struct amd_pmf_dev *dev)
 		return ret;
 	}
 
+	if (ta_sm->pmf_result == TA_PMF_TYPE_SUCCESS && out->actions_count) {
+		dev_dbg(dev->dev, "action count:%u result:%x\n", out->actions_count,
+			ta_sm->pmf_result);
+		amd_pmf_apply_policies(dev, out);
+	}
+
 	return 0;
 }
 
@@ -72,6 +149,7 @@ static int amd_pmf_invoke_cmd_init(struct amd_pmf_dev *dev)
 {
 	struct ta_pmf_shared_memory *ta_sm = NULL;
 	struct tee_param param[MAX_TEE_PARAM];
+	struct ta_pmf_init_table *in = NULL;
 	struct tee_ioctl_invoke_arg arg;
 	int ret = 0;
 
@@ -80,10 +158,21 @@ static int amd_pmf_invoke_cmd_init(struct amd_pmf_dev *dev)
 		return -ENODEV;
 	}
 
+	dev_dbg(dev->dev, "Policy Binary size: %u bytes\n", dev->policy_sz);
+	memset(dev->shbuf, 0, dev->policy_sz);
 	ta_sm = dev->shbuf;
+	in = &ta_sm->pmf_input.init_table;
+
 	ta_sm->command_id = TA_PMF_COMMAND_POLICY_BUILDER_INITIALIZE;
 	ta_sm->if_version = PMF_TA_IF_VERSION_MAJOR;
 
+	in->metadata_macrocheck = false;
+	in->sku_check = false;
+	in->validate = true;
+	in->frequency = pb_actions_ms;
+	in->policies_table.table_size = dev->policy_sz;
+
+	memcpy(in->policies_table.table, dev->policy_buf, dev->policy_sz);
 	amd_pmf_prepare_args(dev, TA_PMF_COMMAND_POLICY_BUILDER_INITIALIZE, &arg, param);
 
 	ret = tee_client_invoke_func(dev->tee_ctx, &arg, param);
@@ -103,6 +192,52 @@ static void amd_pmf_invoke_cmd(struct work_struct *work)
 	schedule_delayed_work(&dev->pb_work, msecs_to_jiffies(pb_actions_ms));
 }
 
+static int amd_pmf_start_policy_engine(struct amd_pmf_dev *dev)
+{
+	u32 cookie, length;
+	int res;
+
+	cookie = readl(dev->policy_buf + POLICY_COOKIE_OFFSET);
+	length = readl(dev->policy_buf + POLICY_COOKIE_LEN);
+
+	if (cookie != POLICY_SIGN_COOKIE || !length)
+		return -EINVAL;
+
+	/* Update the actual length */
+	dev->policy_sz = length + 512;
+	res = amd_pmf_invoke_cmd_init(dev);
+	if (res == TA_PMF_TYPE_SUCCESS) {
+		/* Now its safe to announce that smart pc is enabled */
+		dev->smart_pc_enabled = PMF_SMART_PC_ENABLED;
+		/*
+		 * Start collecting the data from TA FW after a small delay
+		 * or else, we might end up getting stale values.
+		 */
+		schedule_delayed_work(&dev->pb_work, msecs_to_jiffies(pb_actions_ms * 3));
+	} else {
+		dev_err(dev->dev, "ta invoke cmd init failed err: %x\n", res);
+		dev->smart_pc_enabled = PMF_SMART_PC_DISABLED;
+		return res;
+	}
+
+	return 0;
+}
+
+static int amd_pmf_get_bios_buffer(struct amd_pmf_dev *dev)
+{
+	dev->policy_buf = kzalloc(dev->policy_sz, GFP_KERNEL);
+	if (!dev->policy_buf)
+		return -ENOMEM;
+
+	dev->policy_base = devm_ioremap(dev->dev, dev->policy_addr, dev->policy_sz);
+	if (!dev->policy_base)
+		return -ENOMEM;
+
+	memcpy(dev->policy_buf, dev->policy_base, dev->policy_sz);
+
+	return amd_pmf_start_policy_engine(dev);
+}
+
 static int amd_pmf_amdtee_ta_match(struct tee_ioctl_version_data *ver, const void *data)
 {
 	return ver->impl_id == TEE_IMPL_ID_AMDTEE;
@@ -146,7 +281,7 @@ static int amd_pmf_tee_init(struct amd_pmf_dev *dev)
 		goto out_ctx;
 	}
 
-	size = sizeof(struct ta_pmf_shared_memory);
+	size = sizeof(struct ta_pmf_shared_memory) + dev->policy_sz;
 	dev->fw_shm_pool = tee_shm_alloc_kernel_buf(dev->tee_ctx, size);
 	if (IS_ERR(dev->fw_shm_pool)) {
 		dev_err(dev->dev, "Failed to alloc TEE shared memory\n");
@@ -185,16 +320,35 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
 {
 	int ret;
 
+	ret = apmf_check_smart_pc(dev);
+	if (ret) {
+		/*
+		 * Lets not return from here if Smart PC bit is not advertised in
+		 * the BIOS. This way, there will be some amount of power savings
+		 * to the user with static slider (if enabled).
+		 */
+		dev_info(dev->dev, "PMF Smart PC not advertised in BIOS!:%d\n", ret);
+		return -ENODEV;
+	}
+
 	ret = amd_pmf_tee_init(dev);
 	if (ret)
 		return ret;
 
 	INIT_DELAYED_WORK(&dev->pb_work, amd_pmf_invoke_cmd);
-	return 0;
+	amd_pmf_set_dram_addr(dev, true);
+	amd_pmf_get_bios_buffer(dev);
+	dev->prev_data = kzalloc(sizeof(*dev->prev_data), GFP_KERNEL);
+	if (!dev->prev_data)
+		return -ENOMEM;
+
+	return dev->smart_pc_enabled;
 }
 
 void amd_pmf_deinit_smart_pc(struct amd_pmf_dev *dev)
 {
+	kfree(dev->prev_data);
+	kfree(dev->policy_buf);
 	cancel_delayed_work_sync(&dev->pb_work);
 	amd_pmf_tee_deinit(dev);
 }