DRM: Armada: Add Armada DRM driver

This patch adds support for the pair of LCD controllers on the Marvell
Armada 510 SoCs.  This driver supports:
- multiple contiguous scanout buffers for video and graphics
- shm backed cacheable buffer objects for X pixmaps for Vivante GPU
  acceleration
- dual lcd0 and lcd1 crt operation
- video overlay on each LCD crt via DRM planes
- page flipping of the main scanout buffers
- DRM prime for buffer export/import

This driver is trivial to extend to other Armada SoCs.

Included in this commit is the core driver with no output support; output
support is platform and encoder driver dependent.

Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/gpu/drm/armada/armada_output.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2012 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <drm/drmP.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_encoder_slave.h>
+#include "armada_output.h"
+#include "armada_drm.h"
+
+struct armada_connector {
+	struct drm_connector conn;
+	const struct armada_output_type *type;
+};
+
+#define drm_to_armada_conn(c) container_of(c, struct armada_connector, conn)
+
+struct drm_encoder *armada_drm_connector_encoder(struct drm_connector *conn)
+{
+	struct drm_encoder *enc = conn->encoder;
+
+	return enc ? enc : drm_encoder_find(conn->dev, conn->encoder_ids[0]);
+}
+
+static enum drm_connector_status armada_drm_connector_detect(
+	struct drm_connector *conn, bool force)
+{
+	struct armada_connector *dconn = drm_to_armada_conn(conn);
+	enum drm_connector_status status = connector_status_disconnected;
+
+	if (dconn->type->detect) {
+		status = dconn->type->detect(conn, force);
+	} else {
+		struct drm_encoder *enc = armada_drm_connector_encoder(conn);
+
+		if (enc)
+			status = encoder_helper_funcs(enc)->detect(enc, conn);
+	}
+
+	return status;
+}
+
+static void armada_drm_connector_destroy(struct drm_connector *conn)
+{
+	struct armada_connector *dconn = drm_to_armada_conn(conn);
+
+	drm_sysfs_connector_remove(conn);
+	drm_connector_cleanup(conn);
+	kfree(dconn);
+}
+
+static int armada_drm_connector_set_property(struct drm_connector *conn,
+	struct drm_property *property, uint64_t value)
+{
+	struct armada_connector *dconn = drm_to_armada_conn(conn);
+
+	if (!dconn->type->set_property)
+		return -EINVAL;
+
+	return dconn->type->set_property(conn, property, value);
+}
+
+static const struct drm_connector_funcs armada_drm_conn_funcs = {
+	.dpms		= drm_helper_connector_dpms,
+	.fill_modes	= drm_helper_probe_single_connector_modes,
+	.detect		= armada_drm_connector_detect,
+	.destroy	= armada_drm_connector_destroy,
+	.set_property	= armada_drm_connector_set_property,
+};
+
+void armada_drm_encoder_prepare(struct drm_encoder *encoder)
+{
+	encoder_helper_funcs(encoder)->dpms(encoder, DRM_MODE_DPMS_OFF);
+}
+
+void armada_drm_encoder_commit(struct drm_encoder *encoder)
+{
+	encoder_helper_funcs(encoder)->dpms(encoder, DRM_MODE_DPMS_ON);
+}
+
+bool armada_drm_encoder_mode_fixup(struct drm_encoder *encoder,
+	const struct drm_display_mode *mode, struct drm_display_mode *adjusted)
+{
+	return true;
+}
+
+/* Shouldn't this be a generic helper function? */
+int armada_drm_slave_encoder_mode_valid(struct drm_connector *conn,
+	struct drm_display_mode *mode)
+{
+	struct drm_encoder *encoder = armada_drm_connector_encoder(conn);
+	int valid = MODE_BAD;
+
+	if (encoder) {
+		struct drm_encoder_slave *slave = to_encoder_slave(encoder);
+
+		valid = slave->slave_funcs->mode_valid(encoder, mode);
+	}
+	return valid;
+}
+
+int armada_drm_slave_encoder_set_property(struct drm_connector *conn,
+	struct drm_property *property, uint64_t value)
+{
+	struct drm_encoder *encoder = armada_drm_connector_encoder(conn);
+	int rc = -EINVAL;
+
+	if (encoder) {
+		struct drm_encoder_slave *slave = to_encoder_slave(encoder);
+
+		rc = slave->slave_funcs->set_property(encoder, conn, property,
+						      value);
+	}
+	return rc;
+}
+
+int armada_output_create(struct drm_device *dev,
+	const struct armada_output_type *type, const void *data)
+{
+	struct armada_connector *dconn;
+	int ret;
+
+	dconn = kzalloc(sizeof(*dconn), GFP_KERNEL);
+	if (!dconn)
+		return -ENOMEM;
+
+	dconn->type = type;
+
+	ret = drm_connector_init(dev, &dconn->conn, &armada_drm_conn_funcs,
+				 type->connector_type);
+	if (ret) {
+		DRM_ERROR("unable to init connector\n");
+		goto err_destroy_dconn;
+	}
+
+	ret = type->create(&dconn->conn, data);
+	if (ret)
+		goto err_conn;
+
+	ret = drm_sysfs_connector_add(&dconn->conn);
+	if (ret)
+		goto err_sysfs;
+
+	return 0;
+
+ err_sysfs:
+	if (dconn->conn.encoder)
+		dconn->conn.encoder->funcs->destroy(dconn->conn.encoder);
+ err_conn:
+	drm_connector_cleanup(&dconn->conn);
+ err_destroy_dconn:
+	kfree(dconn);
+	return ret;
+}