[PATCH RFC v2 08/10] firmware: riscv: rpmi-tee: cache TEE capabilities

[Amirreza Zarrabi]

Query firmware capabilities during transport initialization and cache
support for memory lending, sharing, segmented parcels and signal buses.

Distinguish REE-accessible memory operations from those restricted to
TEE-to-TEE use so Linux only enables operations available to it.

Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>
---
 drivers/firmware/riscv_rpmi_tee/driver.c           | 73 ++++++++++++++++++++++
 drivers/firmware/riscv_rpmi_tee/rpmi_tee_private.h | 15 +++++
 2 files changed, 88 insertions(+)

diff --git a/drivers/firmware/riscv_rpmi_tee/driver.c b/drivers/firmware/riscv_rpmi_tee/driver.c
index a683f7d28c25..b43a09f5e853 100644
--- a/drivers/firmware/riscv_rpmi_tee/driver.c
+++ b/drivers/firmware/riscv_rpmi_tee/driver.c
@@ -18,6 +18,33 @@
 
 #include "rpmi_tee_private.h"
 
+#define RPMI_TEE_FEATURE_MEMORY_LEND		1
+#define RPMI_TEE_FEATURE_MEMORY_SHARE		2
+#define RPMI_TEE_FEATURE_SIGNAL_BUS		3
+#define RPMI_TEE_FEATURE_MULTISEGMENT_OPS	4
+
+#define RPMI_TEE_MEMORY_FEATURE_UNSUPPORTED		0
+#define RPMI_TEE_MEMORY_FEATURE_TEE_ONLY		1
+#define RPMI_TEE_MEMORY_FEATURE_FULLY_SUPPORTED	2
+
+/**
+ * struct rpmi_tee_probe_features_req - TEE_PROBE_FEATURES request
+ * @feature_id: TEE feature identifier to query.
+ */
+struct rpmi_tee_probe_features_req {
+	__le32 feature_id;
+} __packed;
+
+/**
+ * struct rpmi_tee_probe_features_resp - TEE_PROBE_FEATURES response
+ * @status: RPMI completion status.
+ * @value: Feature-specific value.
+ */
+struct rpmi_tee_probe_features_resp {
+	__le32 status;
+	__le32 value;
+} __packed;
+
 /**
  * struct rpmi_tee_call_req - TEE_CALL request prefix
  * @sender_id: Calling REE endpoint identifier.
@@ -186,6 +213,29 @@ static int rpmi_tee_check_transport(struct rpmi_tee_transport *priv)
 
 /* RPMI TEE SERVICE GRP API. */
 
+/* TEE_PROBE_FEATURES. */
+static int rpmi_tee_probe_features(struct rpmi_tee_transport *priv,
+				   u32 feature_id, u32 *value)
+{
+	struct rpmi_tee_probe_features_req req = {
+		.feature_id = cpu_to_le32(feature_id),
+	};
+	struct rpmi_tee_probe_features_resp resp;
+	size_t resp_len = sizeof(resp);
+	int ret;
+
+	ret = rpmi_tee_send(priv, RPMI_TEE_SRV_PROBE_FEATURES, &req,
+			    sizeof(req), &resp, &resp_len);
+	if (ret)
+		return ret;
+	if (resp_len != sizeof(resp))
+		return -EPROTO;
+
+	*value = get_unaligned_le32(&resp.value);
+
+	return 0;
+}
+
 /* Return the transport that owns @rdev. */
 static struct rpmi_tee_transport *
 rpmi_tee_device_to_transport(struct rpmi_tee_device *rdev)
@@ -371,6 +421,7 @@ static int rpmi_tee_setup_endpoints(struct rpmi_tee_transport *priv)
 static int rpmi_tee_transport_probe(struct platform_device *pdev)
 {
 	struct rpmi_tee_transport *priv;
+	u32 value;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -394,6 +445,28 @@ static int rpmi_tee_transport_probe(struct platform_device *pdev)
 		goto out_failed;
 	}
 
+	ret = rpmi_tee_probe_features(priv, RPMI_TEE_FEATURE_MEMORY_LEND,
+				      &value);
+	if (ret)
+		goto out_failed;
+	priv->mem.lend_ok = value == RPMI_TEE_MEMORY_FEATURE_FULLY_SUPPORTED;
+
+	ret = rpmi_tee_probe_features(priv, RPMI_TEE_FEATURE_MEMORY_SHARE,
+				      &value);
+	if (ret)
+		goto out_failed;
+	priv->mem.share_ok = value == RPMI_TEE_MEMORY_FEATURE_FULLY_SUPPORTED;
+
+	ret = rpmi_tee_probe_features(priv, RPMI_TEE_FEATURE_MULTISEGMENT_OPS,
+				      &priv->mem.multisegment_max);
+	if (ret)
+		goto out_failed;
+
+	ret = rpmi_tee_probe_features(priv, RPMI_TEE_FEATURE_SIGNAL_BUS,
+				      &priv->notif.feature);
+	if (ret)
+		goto out_failed;
+
 	ret = rpmi_tee_setup_endpoints(priv);
 	if (ret) {
 		dev_err_probe(&pdev->dev, ret,
diff --git a/drivers/firmware/riscv_rpmi_tee/rpmi_tee_private.h b/drivers/firmware/riscv_rpmi_tee/rpmi_tee_private.h
index 07e6b9913cb7..0c3cfa0f14ec 100644
--- a/drivers/firmware/riscv_rpmi_tee/rpmi_tee_private.h
+++ b/drivers/firmware/riscv_rpmi_tee/rpmi_tee_private.h
@@ -14,17 +14,28 @@
 /* TEE service group and the services used by this module. */
 #define RPMI_SRVGRP_TEE		0x10
 
+#define RPMI_TEE_SRV_PROBE_FEATURES	0x02
 #define RPMI_TEE_SRV_PROBE_SYSTEM	0x03
 #define RPMI_TEE_SRV_PROBE_DOMAIN	0x04
 #define RPMI_TEE_SRV_PROBE_ENDPOINT	0x05
 #define RPMI_TEE_SRV_CALL		0x18
 
+struct rpmi_tee_notif_state {
+	u32 feature;
+};
+
 struct rpmi_tee_mbox {
 	struct mbox_client client;
 	struct mbox_chan *chan;
 	u32 max_msg_data_size;
 };
 
+struct rpmi_tee_mem_state {
+	u32 multisegment_max;
+	bool lend_ok;
+	bool share_ok;
+};
+
 /**
  * struct rpmi_tee_transport - State for one RPMI TEE transport instance
  * @dev: Parent platform device.
@@ -33,6 +44,8 @@ struct rpmi_tee_mbox {
  * @max_call_resp_size: Maximum TEE_CALL response payload size in bytes.
  * @self_id: Local REE physical endpoint identifier.
  * @devices: List of registered TEE service devices.
+ * @mem: Memory parcel operation state.
+ * @notif: Signal notification state.
  */
 struct rpmi_tee_transport {
 	struct device *dev;
@@ -41,6 +54,8 @@ struct rpmi_tee_transport {
 	size_t max_call_resp_size;
 	u32 self_id;
 	struct list_head devices;
+	struct rpmi_tee_mem_state mem;
+	struct rpmi_tee_notif_state notif;
 };
 
 /* Report local transport errors separately from the returned RPMI status. */

-- 
2.34.1