gsp-phys: backend session API skeleton (P0, inert)

1 files changed, 133 insertions, 0 deletions

diff --git a/kernel/gsp_phys_booter.c b/kernel/gsp_phys_booter.c
index 247dcff..255d79e 100644
--- a/kernel/gsp_phys_booter.c
+++ b/kernel/gsp_phys_booter.c
@@ -4444,6 +4444,139 @@ static int gsp_phys_rm_probe(void __iomem *bar0)
 }
 
 /* ============================================================
+ * Backend session transport API (P0 skeleton, inert)
+ * ============================================================ */
+
+static struct gsp_phys_backend_static_config gsp_phys_backend_static;
+
+int gsp_phys_backend_rpc(u32 function, const void *req, u32 req_len,
+			 void **reply, u32 *reply_len, u32 timeout_ms)
+{
+	struct gsp_phys_status_queue sq;
+	struct gsp_phys_rx_record rec;
+	void __iomem *bar0;
+	void *payload = NULL;
+	u32 generation;
+	int ret;
+
+	if (reply)
+		*reply = NULL;
+	if (reply_len)
+		*reply_len = 0;
+
+	/*
+	 * Lock-free readiness check so a non-READY session is refused without
+	 * taking the real-GSP lock or touching the device. The generation is
+	 * captured before the lock and re-checked under it: a stop that bumps
+	 * the generation between the two checks is seen below and the forward
+	 * is refused instead of racing the release.
+	 */
+	if (gsp_phys_backend_state() != GSP_PHYS_BACKEND_READY ||
+	    !gsp_phys_gpu_claimed() || !boot_stage.rm_init_done ||
+	    boot_stage.rm_unload_submitted) {
+		pr_info("gsp-phys-boot: backend rpc fn%u refused: not ready (state=%d claimed=%u rm_init_done=%u unload_submitted=%u)\n",
+			function, gsp_phys_backend_state(),
+			gsp_phys_gpu_claimed(), boot_stage.rm_init_done,
+			boot_stage.rm_unload_submitted);
+		return -EAGAIN;
+	}
+
+	generation = gsp_phys_backend_generation();
+	bar0 = gsp_phys_gpu_bar0();
+	if (!bar0) {
+		pr_info("gsp-phys-boot: backend rpc fn%u refused: no BAR0\n",
+			function);
+		return -ENODEV;
+	}
+
+	mutex_lock(&gsp_phys_rm_lock);
+	if (gsp_phys_backend_state() != GSP_PHYS_BACKEND_READY ||
+	    gsp_phys_backend_generation() != generation ||
+	    !boot_stage.rm_init_done || boot_stage.rm_unload_submitted) {
+		u32 gen_now = gsp_phys_backend_generation();
+
+		mutex_unlock(&gsp_phys_rm_lock);
+		pr_info("gsp-phys-boot: backend rpc fn%u refused: session changed while waiting for the GSP lock (generation %u -> %u)\n",
+			function, generation, gen_now);
+		return -EAGAIN;
+	}
+
+	ret = gsp_phys_queue_tx_submit(bar0, function, req, req_len);
+	if (ret) {
+		mutex_unlock(&gsp_phys_rm_lock);
+		pr_err("gsp-phys-boot: backend rpc fn%u submit refused: %d\n",
+		       function, ret);
+		return ret;
+	}
+
+	gsp_phys_status_queue_init(&sq);
+	memset(&rec, 0, sizeof(rec));
+	ret = gsp_phys_status_wait(&sq, function, false, 0, timeout_ms, &rec);
+	if (ret) {
+		mutex_unlock(&gsp_phys_rm_lock);
+		pr_err("gsp-phys-boot: backend rpc fn%u no reply within %u ms (%d)\n",
+		       function, timeout_ms, ret);
+		return ret;
+	}
+
+	pr_info("gsp-phys-boot: backend rpc fn%u reply: payload=%u B seqNum=%u rpc.seq=%u rpc_result=0x%x private=0x%x checksum=0x%08x\n",
+		function, rec.payload_len, rec.seq_num, rec.rpc_sequence,
+		rec.rpc_result, rec.rpc_result_private, rec.checksum);
+
+	if (rec.rpc_result != 0) {
+		pr_err("gsp-phys-boot: backend rpc fn%u server rpc_result=0x%x (not success)\n",
+		       function, rec.rpc_result);
+		ret = -EIO;
+		goto out;
+	}
+
+	if (reply && rec.payload_len) {
+		payload = kmemdup(rec.buf + GSP_PHYS_MSG_ELEMENT_PAYLOAD_OFF,
+				  rec.payload_len, GFP_KERNEL);
+		if (!payload) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+	if (reply)
+		*reply = payload;
+	if (reply_len)
+		*reply_len = rec.payload_len;
+
+out:
+	gsp_phys_rx_record_free(&rec);
+	mutex_unlock(&gsp_phys_rm_lock);
+	return ret;
+}
+
+int gsp_phys_backend_static_snapshot(struct gsp_phys_backend_static_config *out)
+{
+	u32 generation;
+
+	if (!out)
+		return -EINVAL;
+
+	if (gsp_phys_backend_state() != GSP_PHYS_BACKEND_READY)
+		return -EAGAIN;
+
+	generation = gsp_phys_backend_generation();
+	mutex_lock(&gsp_phys_rm_lock);
+	if (gsp_phys_backend_state() != GSP_PHYS_BACKEND_READY ||
+	    gsp_phys_backend_generation() != generation) {
+		mutex_unlock(&gsp_phys_rm_lock);
+		return -EAGAIN;
+	}
+	if (!gsp_phys_backend_static.valid) {
+		mutex_unlock(&gsp_phys_rm_lock);
+		pr_debug("gsp-phys-boot: backend static snapshot: cache not populated yet\n");
+		return -ENODATA;
+	}
+	*out = gsp_phys_backend_static;
+	mutex_unlock(&gsp_phys_rm_lock);
+	return 0;
+}
+
+/* ============================================================
  * Host RM client ladder (R1): gsp-phys-rm-call
  * ============================================================ */