[PATCH 3/6] drm/i915: Wrap the preallocated BIOS framebuffer and preserve for KMS fbcon v7

[Jesse Barnes <jbarnes@virtuousgeek.org>]

Retrieve current framebuffer config info from the regs and create an fb
object for the buffer the BIOS or boot loader left us.  This should
allow for smooth transitions to userspace apps once we finish the
initial configuration construction.

v2: check for non-native modes and adjust (Jesse)
    fixup aperture and cmap frees (Imre)
    use unlocked unref if init_bios fails (Jesse)
    fix curly brace around DSPADDR check (Imre)
    comment failure path for pin_and_fence (Imre)
v3: fixup fixup of aperture frees (Chris)
v4: update to current bits (locking & pin_and_fence hack) (Jesse)
v5: move fb config fetch to display code (Jesse)
    re-order hw state readout on initial load to suit fb inherit (Jesse)
    re-add pin_and_fence in fbdev code to make sure we refcount properly (Je
v6: rename to plane_config (Daniel)
    check for valid object when initializing BIOS fb (Jesse)
    split from plane_config readout and other display changes (Jesse)
    drop use_bios_fb option (Chris)
    update comments (Jesse)
    rework fbdev_init_bios for clarity (Jesse)
    drop fb obj ref under lock (Chris)
v7: use fb object from plane_config instead (Ville)
    take ref on fb object (Jesse)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c |   4 +-
 drivers/gpu/drm/i915/intel_drv.h     |   4 +-
 drivers/gpu/drm/i915/intel_fbdev.c   | 235 ++++++++++++++++++++++++++++++++---
 3 files changed, 224 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 94183af..b868331 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7817,11 +7817,11 @@ mode_fits_in_fbdev(struct drm_device *dev,
 	if (dev_priv->fbdev == NULL)
 		return NULL;
 
-	obj = dev_priv->fbdev->ifb.obj;
+	obj = dev_priv->fbdev->fb->obj;
 	if (obj == NULL)
 		return NULL;
 
-	fb = &dev_priv->fbdev->ifb.base;
+	fb = &dev_priv->fbdev->fb->base;
 	if (fb->pitches[0] < intel_framebuffer_pitch_for_width(mode->hdisplay,
 							       fb->bits_per_pixel))
 		return NULL;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 4787773..5f9182e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -110,9 +110,10 @@ struct intel_framebuffer {
 
 struct intel_fbdev {
 	struct drm_fb_helper helper;
-	struct intel_framebuffer ifb;
+	struct intel_framebuffer *fb;
 	struct list_head fbdev_list;
 	struct drm_display_mode *our_mode;
+	int preferred_bpp;
 };
 
 struct intel_encoder {
@@ -671,6 +672,7 @@ int intel_framebuffer_init(struct drm_device *dev,
 			   struct intel_framebuffer *ifb,
 			   struct drm_mode_fb_cmd2 *mode_cmd,
 			   struct drm_i915_gem_object *obj);
+void intel_fbdev_init_bios(struct drm_device *dev);
 void intel_framebuffer_fini(struct intel_framebuffer *fb);
 void intel_prepare_page_flip(struct drm_device *dev, int plane);
 void intel_finish_page_flip(struct drm_device *dev, int pipe);
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 284c3eb..db75f22 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -62,11 +62,20 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 {
 	struct intel_fbdev *ifbdev =
 		container_of(helper, struct intel_fbdev, helper);
+	struct intel_framebuffer *fb;
 	struct drm_device *dev = helper->dev;
 	struct drm_mode_fb_cmd2 mode_cmd = {};
 	struct drm_i915_gem_object *obj;
 	int size, ret;
 
+	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
+	if (!fb) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ifbdev->fb = fb;
+
 	/* we don't do packed 24bpp */
 	if (sizes->surface_bpp == 24)
 		sizes->surface_bpp = 32;
@@ -97,7 +106,7 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 		goto out_unref;
 	}
 
-	ret = intel_framebuffer_init(dev, &ifbdev->ifb, &mode_cmd, obj);
+	ret = intel_framebuffer_init(dev, ifbdev->fb, &mode_cmd, obj);
 	if (ret)
 		goto out_unpin;
 
@@ -116,7 +125,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 {
 	struct intel_fbdev *ifbdev =
 		container_of(helper, struct intel_fbdev, helper);
-	struct intel_framebuffer *intel_fb = &ifbdev->ifb;
+	struct intel_framebuffer *intel_fb = ifbdev->fb;
 	struct drm_device *dev = helper->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct fb_info *info;
@@ -148,7 +157,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 
 	info->par = helper;
 
-	fb = &ifbdev->ifb.base;
+	fb = &ifbdev->fb->base;
 
 	ifbdev->helper.fb = fb;
 	ifbdev->helper.fbdev = info;
@@ -194,14 +203,14 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	 * If the object is stolen however, it will be full of whatever
 	 * garbage was left in there.
 	 */
-	if (ifbdev->ifb.obj->stolen)
+	if (ifbdev->fb->obj->stolen)
 		memset_io(info->screen_base, 0, info->screen_size);
 
 	/* Use default scratch pixmap (info->pixmap.flags = FB_PIXMAP_SYSTEM) */
 
-	DRM_DEBUG_KMS("allocated %dx%d fb: 0x%08lx, bo %p\n",
+	DRM_DEBUG_KMS("allocated %dx%d fb: map %p, bo %p, size 0x%lx\n",
 		      fb->width, fb->height,
-		      i915_gem_obj_ggtt_offset(obj), obj);
+		      info->screen_base, obj, info->screen_size);
 
 	mutex_unlock(&dev->struct_mutex);
 	vga_switcheroo_client_fb_set(dev->pdev, info);
@@ -236,6 +245,96 @@ static void intel_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 	*blue = intel_crtc->lut_b[regno] << 8;
 }
 
+static struct drm_fb_helper_crtc *
+intel_fb_helper_crtc(struct drm_fb_helper *fb_helper, struct drm_crtc *crtc)
+{
+	int i;
+
+	for (i = 0; i < fb_helper->crtc_count; i++)
+		if (fb_helper->crtc_info[i].mode_set.crtc == crtc)
+			return &fb_helper->crtc_info[i];
+
+	return NULL;
+}
+
+/*
+ * Try to read the BIOS display configuration and use it for the initial
+ * fb configuration.
+ *
+ * The BIOS or boot loader will generally create an initial display
+ * configuration for us that includes some set of active pipes and displays.
+ * This routine tries to figure out which pipes and connectors are active
+ * and stuffs them into the crtcs and modes array given to us by the
+ * drm_fb_helper code.
+ *
+ * The overall sequence is:
+ *   intel_fbdev_init - from driver load
+ *     intel_fbdev_init_bios - initialize the intel_fbdev using BIOS data
+ *     drm_fb_helper_init - build fb helper structs
+ *     drm_fb_helper_single_add_all_connectors - more fb helper structs
+ *   intel_fbdev_initial_config - apply the config
+ *     drm_fb_helper_initial_config - call ->probe then register_framebuffer()
+ *         drm_setup_crtcs - build crtc config for fbdev
+ *           intel_fb_initial_config - find active connectors etc
+ *         drm_fb_helper_single_fb_probe - set up fbdev
+ *           intelfb_create - re-use or alloc fb, build out fbdev structs
+ *
+ * If the BIOS or boot loader leaves the display in VGA mode, there's not
+ * much we can do; switching out of that mode involves allocating a new,
+ * high res buffer, and also recalculating bandwidth requirements for the
+ * new bpp configuration.
+ */
+static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
+				    struct drm_fb_helper_crtc **crtcs,
+				    struct drm_display_mode **modes,
+				    bool *enabled, int width, int height)
+{
+	int i;
+
+	for (i = 0; i < fb_helper->connector_count; i++) {
+		struct drm_connector *connector;
+		struct drm_encoder *encoder;
+
+		connector = fb_helper->connector_info[i]->connector;
+		if (!enabled[i]) {
+			DRM_DEBUG_KMS("connector %d not enabled, skipping\n",
+				      connector->base.id);
+			continue;
+		}
+
+		encoder = connector->encoder;
+		if (!encoder || !encoder->crtc) {
+			DRM_DEBUG_KMS("connector %d has no encoder or crtc, skipping\n",
+				      connector->base.id);
+			continue;
+		}
+
+		if (WARN_ON(!encoder->crtc->enabled)) {
+			DRM_DEBUG_KMS("connector %s on crtc %d has inconsistent state, aborting\n",
+				      drm_get_connector_name(connector),
+				      encoder->crtc->base.id);
+			return false;
+		}
+
+		if (!to_intel_crtc(encoder->crtc)->active) {
+			DRM_DEBUG_KMS("connector %s on inactive crtc %d, borting\n",
+				      drm_get_connector_name(connector),
+				      encoder->crtc->base.id);
+			return false;
+		}
+
+		modes[i] = &encoder->crtc->mode;
+		crtcs[i] = intel_fb_helper_crtc(fb_helper, encoder->crtc);
+
+		DRM_DEBUG_KMS("connector %s on crtc %d: %s\n",
+			      drm_get_connector_name(connector),
+			      encoder->crtc->base.id,
+			      modes[i]->name);
+	}
+
+	return true;
+}
+
 static struct drm_fb_helper_funcs intel_fb_helper_funcs = {
 	.gamma_set = intel_crtc_fb_gamma_set,
 	.gamma_get = intel_crtc_fb_gamma_get,
@@ -258,8 +357,102 @@ static void intel_fbdev_destroy(struct drm_device *dev,
 
 	drm_fb_helper_fini(&ifbdev->helper);
 
-	drm_framebuffer_unregister_private(&ifbdev->ifb.base);
-	intel_framebuffer_fini(&ifbdev->ifb);
+	drm_framebuffer_unregister_private(&ifbdev->fb->base);
+	intel_framebuffer_fini(ifbdev->fb);
+	kfree(ifbdev->fb);
+}
+
+/*
+ * Build an intel_fbdev struct using a BIOS allocated framebuffer, if possible.
+ * The core display code will have read out the current plane configuration,
+ * so we use that to figure out if there's an object for us to use as the
+ * fb, and if so, we re-use it for the fbdev configuration.
+ *
+ * Note we only support a single fb shared across pipes for boot (mostly for
+ * fbcon), so we just find the biggest and use that.
+ */
+void intel_fbdev_init_bios(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_fbdev *ifbdev;
+	struct intel_framebuffer *fb = NULL;
+	struct drm_crtc *crtc;
+	struct intel_crtc *intel_crtc;
+	struct intel_plane_config *plane_config = NULL;
+	unsigned int last_size = 0;
+
+	ifbdev = kzalloc(sizeof(struct intel_fbdev), GFP_KERNEL);
+	if (ifbdev == NULL) {
+		DRM_DEBUG_KMS("failed to alloc intel fbdev\n");
+		return;
+	}
+
+	/* Find the largest framebuffer to use, then free the others */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		intel_crtc = to_intel_crtc(crtc);
+
+		if (!intel_crtc->active || !intel_crtc->plane_config.fb->obj) {
+			DRM_DEBUG_KMS("pipe %c not active or no fb, skipping\n",
+				      pipe_name(intel_crtc->pipe));
+			continue;
+		}
+
+		if (intel_crtc->plane_config.size > last_size) {
+			plane_config = &intel_crtc->plane_config;
+			last_size = plane_config->size;
+			fb = plane_config->fb;
+		}
+	}
+
+	/* Free unused fbs */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		struct intel_framebuffer *cur_fb;
+
+		intel_crtc = to_intel_crtc(crtc);
+		cur_fb = intel_crtc->plane_config.fb;
+
+		if (cur_fb && cur_fb != fb)
+			intel_framebuffer_fini(cur_fb);
+	}
+
+	if (!fb) {
+		DRM_DEBUG_KMS("no active pipes found, not using BIOS config\n");
+		goto out_free;
+	}
+
+	ifbdev->preferred_bpp = plane_config->fb->base.bits_per_pixel;
+	ifbdev->helper.funcs = &intel_fb_helper_funcs;
+	ifbdev->helper.funcs->initial_config = intel_fb_initial_config;
+	ifbdev->fb = fb;
+
+	/* Assuming a single fb across all pipes here */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		intel_crtc = to_intel_crtc(crtc);
+
+		if (!intel_crtc->active)
+			continue;
+
+		/*
+		 * This should only fail on the first one so we don't need
+		 * to cleanup any secondary crtc->fbs
+		 */
+		if (intel_pin_and_fence_fb_obj(dev, fb->obj, NULL))
+			goto out_unref_obj;
+
+		crtc->fb = &fb->base;
+		drm_gem_object_reference(&fb->obj->base);
+		drm_framebuffer_reference(&fb->base);
+	}
+
+	dev_priv->fbdev = ifbdev;
+
+	DRM_DEBUG_KMS("using BIOS fb for initial console\n");
+	return;
+
+out_unref_obj:
+	intel_framebuffer_fini(fb);
+out_free:
+	kfree(ifbdev);
 }
 
 int intel_fbdev_init(struct drm_device *dev)
@@ -268,17 +461,25 @@ int intel_fbdev_init(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
 
-	ifbdev = kzalloc(sizeof(*ifbdev), GFP_KERNEL);
-	if (!ifbdev)
-		return -ENOMEM;
+	/* This may fail, if so, dev_priv->fbdev won't be set below */
+	intel_fbdev_init_bios(dev);
 
-	dev_priv->fbdev = ifbdev;
-	ifbdev->helper.funcs = &intel_fb_helper_funcs;
+	if ((ifbdev = dev_priv->fbdev) == NULL) {
+		ifbdev = kzalloc(sizeof(struct intel_fbdev), GFP_KERNEL);
+		if (ifbdev == NULL)
+			return -ENOMEM;
+
+		ifbdev->helper.funcs = &intel_fb_helper_funcs;
+		ifbdev->preferred_bpp = 32;
+
+		dev_priv->fbdev = ifbdev;
+	}
 
 	ret = drm_fb_helper_init(dev, &ifbdev->helper,
 				 INTEL_INFO(dev)->num_pipes,
 				 4);
 	if (ret) {
+		dev_priv->fbdev = NULL;
 		kfree(ifbdev);
 		return ret;
 	}
@@ -291,9 +492,10 @@ int intel_fbdev_init(struct drm_device *dev)
 void intel_fbdev_initial_config(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_fbdev *ifbdev = dev_priv->fbdev;
 
 	/* Due to peculiar init order wrt to hpd handling this is separate. */
-	drm_fb_helper_initial_config(&dev_priv->fbdev->helper, 32);
+	drm_fb_helper_initial_config(&ifbdev->helper, ifbdev->preferred_bpp);
 }
 
 void intel_fbdev_fini(struct drm_device *dev)
@@ -322,7 +524,7 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state)
 	 * been restored from swap. If the object is stolen however, it will be
 	 * full of whatever garbage was left in there.
 	 */
-	if (state == FBINFO_STATE_RUNNING && ifbdev->ifb.obj->stolen)
+	if (state == FBINFO_STATE_RUNNING && ifbdev->fb->obj->stolen)
 		memset_io(info->screen_base, 0, info->screen_size);
 
 	fb_set_suspend(info, state);
@@ -333,7 +535,8 @@ MODULE_LICENSE("GPL and additional rights");
 void intel_fbdev_output_poll_changed(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
+	if (dev_priv->fbdev)
+		drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
 }
 
 void intel_fbdev_restore_mode(struct drm_device *dev)
-- 
1.8.4.2