[PATCH 5/9] drm/i915/pxp: Add GSC-CS backend to send GSC fw messages

[Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>]

Add GSC engine based method for sending PXP firmware packets
to the GSC firmware for MTL (and future) products. Use the newly
added helpers to populate the GSC-CS memory header and send the
message packet to the FW by dispatching the GSC_HECI_CMD_PKT
instruction on the GSC engine.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
---
 drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c | 92 ++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c b/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c
index 97ca187e6fde..84045e18591e 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_gsccs.c
@@ -6,6 +6,7 @@
 #include "gem/i915_gem_internal.h"
 
 #include "gt/intel_context.h"
+#include "gt/uc/intel_gsc_uc_heci_cmd_submit.h"
 
 #include "i915_drv.h"
 #include "intel_pxp_cmd_interface_43.h"
@@ -39,6 +40,97 @@ static inline struct gsccs_teelink_priv *pxp_to_gsccs_priv(struct intel_pxp *pxp
 	return (struct gsccs_teelink_priv *)pxp->gsccs_priv;
 }
 
+static int gsccs_send_message(struct intel_pxp *pxp,
+			      void *msg_in, size_t msg_in_size,
+			      void *msg_out, size_t msg_out_size_max,
+			      size_t *msg_out_len)
+{
+	struct intel_gt *gt = pxp->ctrl_gt;
+	struct drm_i915_private *i915 = gt->i915;
+	struct gsccs_session_resources *exec = &pxp_to_gsccs_priv(pxp)->arb_exec_res;
+	struct intel_gsc_mtl_header *header = exec->pkt_vaddr;
+	struct intel_gsc_heci_non_priv_pkt pkt;
+	size_t max_msg_size;
+	u32 reply_size;
+	int ret;
+
+	if (!intel_uc_uses_gsc_uc(&gt->uc))
+		return -ENODEV;
+
+	if (!exec->ce)
+		return -ENODEV;
+
+	max_msg_size = PXP43_MAX_HECI_IN_SIZE - sizeof(*header);
+
+	if (msg_in_size > max_msg_size || msg_out_size_max > max_msg_size)
+		return -ENOSPC;
+
+	mutex_lock(&exec->cmd_mutex);
+
+	if (!exec->pkt_vma || !exec->bb_vma)
+		return -ENOENT;
+
+	memset(header, 0, sizeof(*header));
+	intel_gsc_uc_heci_cmd_emit_mtl_header(header, MTL_HECI_CLIENT_PXP, msg_in_size,
+					      exec->host_session_handle, 0);
+
+	memcpy(exec->pkt_vaddr + sizeof(*header), msg_in, msg_in_size);
+
+	pkt.addr_in = i915_vma_offset(exec->pkt_vma);
+	pkt.size_in = header->message_size;
+	pkt.addr_out = pkt.addr_in + PXP43_MAX_HECI_IN_SIZE;
+	pkt.size_out = msg_out_size_max + sizeof(*header);
+	pkt.heci_pkt_vma = exec->pkt_vma;
+	pkt.bb_vma = exec->bb_vma;
+
+	ret = intel_gsc_uc_heci_cmd_submit_nonpriv(&pxp->ctrl_gt->uc.gsc,
+						   exec->ce, &pkt, exec->bb_vaddr, 500);
+	if (ret) {
+		drm_err(&i915->drm, "failed to send gsc PXP msg (%d)\n", ret);
+		goto unlock;
+	}
+
+	/* we keep separate location for reply, so get the response header loc first */
+	header = exec->pkt_vaddr + PXP43_MAX_HECI_IN_SIZE;
+
+	/* Response validity marker, status and busyness */
+	if (header->validity_marker != MTL_HECI_VALIDITY_MARKER) {
+		drm_err(&i915->drm, "gsc PXP reply with invalid validity marker\n");
+		ret = -EINVAL;
+		goto unlock;
+	}
+	if (header->status != 0) {
+		drm_dbg(&i915->drm, "gsc PXP reply status has error = 0x%08x\n",
+			header->status);
+		ret = -EINVAL;
+		goto unlock;
+	}
+	if (header->flags & MTL_GSC_HDR_FLAG_MSG_PENDING) {
+		drm_dbg(&i915->drm, "gsc PXP reply is busy\n");
+		ret = -EAGAIN;
+		goto unlock;
+	}
+
+	reply_size = header->message_size - sizeof(*header);
+	if (reply_size > msg_out_size_max) {
+		drm_warn(&i915->drm, "caller with insufficient PXP reply size %u (%ld)\n",
+			 reply_size, msg_out_size_max);
+		reply_size = msg_out_size_max;
+	} else if (reply_size != msg_out_size_max) {
+		drm_dbg(&i915->drm, "caller unexpected PXP reply size %u (%ld)\n",
+			reply_size, msg_out_size_max);
+	}
+
+	memcpy(msg_out, exec->pkt_vaddr + PXP43_MAX_HECI_IN_SIZE + sizeof(*header),
+	       reply_size);
+	if (msg_out_len)
+		*msg_out_len = reply_size;
+
+unlock:
+	mutex_unlock(&exec->cmd_mutex);
+	return ret;
+}
+
 int intel_pxp_gsccs_create_session(struct intel_pxp *pxp,
 				   int arb_session_id)
 {
-- 
2.39.0