[Intel-gfx] {Intel-gfx] [RFC 01/14] drm/i915: allocate gem memory for mipi dbi cmd buffer

[Gaurav K Singh]

Allocate gem memory for MIPI DBI command buffer. This memory
will be used when sending command via DBI interface.

v2: lock mutex before gem object unreference and later set gem obj ptr to NULL (Gaurav)

Signed-off-by: Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu at intel.com>
Signed-off-by: Gaurav K Singh <gaurav.k.singh at intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar at intel.com>
---
 drivers/gpu/drm/i915/intel_dsi.c |   40 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dsi.h |    4 ++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 98998e9..011fef2 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -407,9 +407,35 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder)
 	enum pipe pipe = intel_crtc->pipe;
 	enum port port;
 	u32 tmp;
+	int ret;
 
 	DRM_DEBUG_KMS("\n");
 
+	if (!intel_dsi->gem_obj && is_cmd_mode(intel_dsi)) {
+		intel_dsi->gem_obj = i915_gem_alloc_object(dev, 4096);
+		if (!intel_dsi->gem_obj) {
+			DRM_ERROR("Failed to allocate seqno page\n");
+			return;
+		}
+
+		ret = i915_gem_object_set_cache_level(intel_dsi->gem_obj,
+						      I915_CACHE_LLC);
+		if (ret)
+			goto err_unref;
+
+		ret = i915_gem_obj_ggtt_pin(intel_dsi->gem_obj, 4096, 0);
+		if (ret) {
+err_unref:
+			drm_gem_object_unreference(&intel_dsi->gem_obj->base);
+			return;
+		}
+
+		intel_dsi->cmd_buff =
+				kmap(sg_page(intel_dsi->gem_obj->pages->sgl));
+		intel_dsi->cmd_buff_phy_addr = page_to_phys(
+				sg_page(intel_dsi->gem_obj->pages->sgl));
+	}
+
 	/* Disable DPOunit clock gating, can stall pipe
 	 * and we need DPLL REFA always enabled */
 	tmp = I915_READ(DPLL(pipe));
@@ -555,6 +581,7 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+	struct drm_device *dev = encoder->base.dev;
 	u32 val;
 
 	DRM_DEBUG_KMS("\n");
@@ -571,6 +598,15 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder)
 
 	msleep(intel_dsi->panel_off_delay);
 	msleep(intel_dsi->panel_pwr_cycle_delay);
+
+	if (intel_dsi->gem_obj) {
+		kunmap(intel_dsi->cmd_buff);
+		i915_gem_object_ggtt_unpin(intel_dsi->gem_obj);
+		mutex_lock(&dev->struct_mutex);
+		drm_gem_object_unreference(&intel_dsi->gem_obj->base);
+		mutex_unlock(&dev->struct_mutex);
+	}
+	intel_dsi->gem_obj = NULL;
 }
 
 static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
@@ -1042,6 +1078,10 @@ void intel_dsi_init(struct drm_device *dev)
 		intel_dsi->ports = (1 << PORT_C);
 	}
 
+	intel_dsi->cmd_buff = NULL;
+	intel_dsi->cmd_buff_phy_addr = 0;
+	intel_dsi->gem_obj = NULL;
+
 	/* Create a DSI host (and a device) for each port. */
 	for_each_dsi_port(port, intel_dsi->ports) {
 		struct intel_dsi_host *host;
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 2784ac4..36ca3cc 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -44,6 +44,10 @@ struct intel_dsi {
 
 	struct intel_connector *attached_connector;
 
+	struct drm_i915_gem_object *gem_obj;
+	void *cmd_buff;
+	dma_addr_t cmd_buff_phy_addr;
+
 	/* bit mask of ports being driven */
 	u16 ports;
 
-- 
1.7.9.5