drm/fb-helper: Remove drm_fb_helper_crtc

struct drm_fb_helper_crtc is now just a wrapper around drm_mode_set so
use that directly instead and attach it as a modeset array onto
drm_client_dev. drm_fb_helper will use this array to store its modesets
which means it will always initialize a drm_client, but it will not
register the client (callbacks) unless it's the generic fbdev emulation.

Code will later be moved to drm_client, so add code there in a new file
drm_client_modeset.c with MIT license to match drm_fb_helper.c.

The modeset connector array size is hardcoded for the cloned case to avoid
having to pass in a value from the driver. A value of 8 is chosen to err
on the safe side. This means that the max connector argument for
drm_fb_helper_init() and drm_fb_helper_fbdev_setup() isn't used anymore,
a todo entry for this is added.

In pan_display_atomic() restore_fbdev_mode_force() is used instead of
restore_fbdev_mode_atomic() because that one will later become internal
to drm_client_modeset.

Locking order:
1. drm_fb_helper->lock
2. drm_master_internal_acquire
3. drm_client_dev->modeset_mutex

v6: Improve commit message (Sam Ravnborg)

v3:
- Use full drm_client_init/release for the modesets (Daniel Vetter)
- drm_client_for_each_modeset: use lockdep_assert_held (Daniel Vetter)
- Hook up to Documentation/gpu/drm-client.rst (Daniel Vetter)

v2:
- Add modesets array to drm_client (Daniel Vetter)
- Use a new file for the modeset code (Daniel Vetter)
- File has to be MIT licensed (Emmanuel Vadot)
- Add copyrights from drm_fb_helper.c

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190531140117.37751-3-noralf@tronnes.org

1 files changed, 104 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
new file mode 100644
index 000000000000..66770ed3299e
--- /dev/null
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2018 Noralf Trønnes
+ * Copyright (c) 2006-2009 Red Hat Inc.
+ * Copyright (c) 2006-2008 Intel Corporation
+ *   Jesse Barnes <jesse.barnes@intel.com>
+ * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
+ */
+
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include <drm/drm_client.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_device.h>
+
+int drm_client_modeset_create(struct drm_client_dev *client)
+{
+	struct drm_device *dev = client->dev;
+	unsigned int num_crtc = dev->mode_config.num_crtc;
+	unsigned int max_connector_count = 1;
+	struct drm_mode_set *modeset;
+	struct drm_crtc *crtc;
+	unsigned int i = 0;
+
+	/* Add terminating zero entry to enable index less iteration */
+	client->modesets = kcalloc(num_crtc + 1, sizeof(*client->modesets), GFP_KERNEL);
+	if (!client->modesets)
+		return -ENOMEM;
+
+	mutex_init(&client->modeset_mutex);
+
+	drm_for_each_crtc(crtc, dev)
+		client->modesets[i++].crtc = crtc;
+
+	/* Cloning is only supported in the single crtc case. */
+	if (num_crtc == 1)
+		max_connector_count = DRM_CLIENT_MAX_CLONED_CONNECTORS;
+
+	for (modeset = client->modesets; modeset->crtc; modeset++) {
+		modeset->connectors = kcalloc(max_connector_count,
+					      sizeof(*modeset->connectors), GFP_KERNEL);
+		if (!modeset->connectors)
+			goto err_free;
+	}
+
+	return 0;
+
+err_free:
+	drm_client_modeset_free(client);
+
+	return -ENOMEM;
+}
+
+void drm_client_modeset_release(struct drm_client_dev *client)
+{
+	struct drm_mode_set *modeset;
+	unsigned int i;
+
+	drm_client_for_each_modeset(modeset, client) {
+		drm_mode_destroy(client->dev, modeset->mode);
+		modeset->mode = NULL;
+		modeset->fb = NULL;
+
+		for (i = 0; i < modeset->num_connectors; i++) {
+			drm_connector_put(modeset->connectors[i]);
+			modeset->connectors[i] = NULL;
+		}
+		modeset->num_connectors = 0;
+	}
+}
+/* TODO: Remove export when modeset code has been moved over */
+EXPORT_SYMBOL(drm_client_modeset_release);
+
+void drm_client_modeset_free(struct drm_client_dev *client)
+{
+	struct drm_mode_set *modeset;
+
+	mutex_lock(&client->modeset_mutex);
+
+	drm_client_modeset_release(client);
+
+	drm_client_for_each_modeset(modeset, client)
+		kfree(modeset->connectors);
+
+	mutex_unlock(&client->modeset_mutex);
+
+	mutex_destroy(&client->modeset_mutex);
+	kfree(client->modesets);
+}
+
+struct drm_mode_set *drm_client_find_modeset(struct drm_client_dev *client, struct drm_crtc *crtc)
+{
+	struct drm_mode_set *modeset;
+
+	drm_client_for_each_modeset(modeset, client)
+		if (modeset->crtc == crtc)
+			return modeset;
+
+	return NULL;
+}
+/* TODO: Remove export when modeset code has been moved over */
+EXPORT_SYMBOL(drm_client_find_modeset);