Message-Id: <1471193526-22844-3-git-send-email-noralf@tronnes.org>
Date:	Sun, 14 Aug 2016 18:52:05 +0200
From:	Noralf Trønnes <noralf@...nnes.org>
To:	dri-devel@...ts.freedesktop.org
Cc:	dh.herrmann@...il.com, linux-kernel@...r.kernel.org,
	Noralf Trønnes <noralf@...nnes.org>
Subject: [PATCH v3 2/3] drm: simpledrm: add fbdev fallback support

Create a simple fbdev device during SimpleDRM setup so legacy user-space
and fbcon can use it.

Original work by David Herrmann.

Cc: dh.herrmann@...il.com
Signed-off-by: Noralf Trønnes <noralf@...nnes.org>
---

Changes from version 2:
- Switch to using drm_fb_helper in preparation for future panic handling
  which needs an enabled pipeline.

Changes from version 1:
  No changes

Changes from previous version:
- Remove the DRM_SIMPLEDRM_FBDEV kconfig option and use DRM_FBDEV_EMULATION
- Suspend fbcon/fbdev when the pipeline is enabled, resume in lastclose
- Add FBINFO_CAN_FORCE_OUTPUT flag so we get oops'es on the console

 drivers/gpu/drm/simpledrm/Kconfig           |   3 +
 drivers/gpu/drm/simpledrm/Makefile          |   1 +
 drivers/gpu/drm/simpledrm/simpledrm.h       |  32 ++++-
 drivers/gpu/drm/simpledrm/simpledrm_drv.c   |   4 +
 drivers/gpu/drm/simpledrm/simpledrm_fbdev.c | 201 ++++++++++++++++++++++++++++
 drivers/gpu/drm/simpledrm/simpledrm_kms.c   |  10 +-
 6 files changed, 249 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/drm/simpledrm/simpledrm_fbdev.c

diff --git a/drivers/gpu/drm/simpledrm/Kconfig b/drivers/gpu/drm/simpledrm/Kconfig
index f45b25d..9454536 100644
--- a/drivers/gpu/drm/simpledrm/Kconfig
+++ b/drivers/gpu/drm/simpledrm/Kconfig
@@ -13,6 +13,9 @@ config DRM_SIMPLEDRM
 	  SimpleDRM supports "simple-framebuffer" DeviceTree objects and
 	  compatible platform framebuffers.

+	  If fbdev support is enabled, this driver will also provide an fbdev
+	  compatibility layer.
+
 	  If unsure, say Y.

 	  To compile this driver as a module, choose M here: the
diff --git a/drivers/gpu/drm/simpledrm/Makefile b/drivers/gpu/drm/simpledrm/Makefile
index f6a62dc..7087245 100644
--- a/drivers/gpu/drm/simpledrm/Makefile
+++ b/drivers/gpu/drm/simpledrm/Makefile
@@ -1,4 +1,5 @@
 simpledrm-y :=	simpledrm_drv.o simpledrm_kms.o simpledrm_gem.o \
 		simpledrm_damage.o
+simpledrm-$(CONFIG_DRM_FBDEV_EMULATION) += simpledrm_fbdev.o

 obj-$(CONFIG_DRM_SIMPLEDRM) := simpledrm.o
diff --git a/drivers/gpu/drm/simpledrm/simpledrm.h b/drivers/gpu/drm/simpledrm/simpledrm.h
index 481acc2..f01b75d 100644
--- a/drivers/gpu/drm/simpledrm/simpledrm.h
+++ b/drivers/gpu/drm/simpledrm/simpledrm.h
@@ -17,13 +17,13 @@

 struct simplefb_format;
 struct regulator;
-struct fb_info;
 struct clk;

 struct sdrm_device {
 	struct drm_device *ddev;
 	struct drm_simple_display_pipe pipe;
 	struct drm_connector conn;
+	struct sdrm_fbdev *fbdev;

 	/* framebuffer information */
 	const struct simplefb_format *fb_sformat;
@@ -46,6 +46,7 @@ struct sdrm_device {
 #endif
 };

+void sdrm_lastclose(struct drm_device *ddev);
 int sdrm_drm_modeset_init(struct sdrm_device *sdrm);
 int sdrm_drm_mmap(struct file *filp, struct vm_area_struct *vma);

@@ -87,4 +88,33 @@ struct sdrm_framebuffer {

 #define to_sdrm_fb(x) container_of(x, struct sdrm_framebuffer, base)

+#ifdef CONFIG_DRM_FBDEV_EMULATION
+
+void sdrm_fbdev_init(struct sdrm_device *sdrm);
+void sdrm_fbdev_cleanup(struct sdrm_device *sdrm);
+void sdrm_fbdev_display_pipe_update(struct sdrm_device *sdrm,
+				    struct drm_framebuffer *fb);
+void sdrm_fbdev_restore_mode(struct sdrm_device *sdrm);
+
+#else
+
+static inline void sdrm_fbdev_init(struct sdrm_device *sdrm)
+{
+}
+
+static inline void sdrm_fbdev_cleanup(struct sdrm_device *sdrm)
+{
+}
+
+static inline void sdrm_fbdev_display_pipe_update(struct sdrm_device *sdrm,
+						  struct drm_framebuffer *fb)
+{
+}
+
+static inline void sdrm_fbdev_restore_mode(struct sdrm_device *sdrm)
+{
+}
+
+#endif
+
 #endif /* SDRM_DRV_H */
diff --git a/drivers/gpu/drm/simpledrm/simpledrm_drv.c b/drivers/gpu/drm/simpledrm/simpledrm_drv.c
index e5b6f75..a4e6566 100644
--- a/drivers/gpu/drm/simpledrm/simpledrm_drv.c
+++ b/drivers/gpu/drm/simpledrm/simpledrm_drv.c
@@ -42,6 +42,7 @@ static struct drm_driver sdrm_drm_driver = {
 	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
 			   DRIVER_ATOMIC,
 	.fops = &sdrm_drm_fops,
+	.lastclose = sdrm_lastclose,

 	.gem_free_object = sdrm_gem_free_object,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
@@ -448,6 +449,8 @@ static int sdrm_simplefb_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_regulators;

+	sdrm_fbdev_init(ddev->dev_private);
+
 	DRM_INFO("Initialized %s on minor %d\n", ddev->driver->name,
 		 ddev->primary->index);

@@ -473,6 +476,7 @@ static int sdrm_simplefb_remove(struct platform_device *pdev)
 	struct drm_device *ddev = platform_get_drvdata(pdev);
 	struct sdrm_device *sdrm = ddev->dev_private;

+	sdrm_fbdev_cleanup(sdrm);
 	drm_dev_unregister(ddev);
 	drm_mode_config_cleanup(ddev);

diff --git a/drivers/gpu/drm/simpledrm/simpledrm_fbdev.c b/drivers/gpu/drm/simpledrm/simpledrm_fbdev.c
new file mode 100644
index 0000000..4038dd9
--- /dev/null
+++ b/drivers/gpu/drm/simpledrm/simpledrm_fbdev.c
@@ -0,0 +1,201 @@
+/*
+ * SimpleDRM firmware framebuffer driver
+ * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@...il.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_helper.h>
+#include <linux/console.h>
+#include <linux/fb.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/simplefb.h>
+
+#include "simpledrm.h"
+
+struct sdrm_fbdev {
+	struct drm_fb_helper fb_helper;
+	struct drm_framebuffer fb;
+};
+
+static inline struct sdrm_fbdev *to_sdrm_fbdev(struct drm_fb_helper *helper)
+{
+	return container_of(helper, struct sdrm_fbdev, fb_helper);
+}
+
+static struct fb_ops sdrm_fbdev_ops = {
+	.owner		= THIS_MODULE,
+	.fb_fillrect	= drm_fb_helper_cfb_fillrect,
+	.fb_copyarea	= drm_fb_helper_cfb_copyarea,
+	.fb_imageblit	= drm_fb_helper_cfb_imageblit,
+	.fb_check_var	= drm_fb_helper_check_var,
+	.fb_set_par	= drm_fb_helper_set_par,
+	.fb_setcmap	= drm_fb_helper_setcmap,
+};
+
+static struct drm_framebuffer_funcs sdrm_fb_funcs = {
+	.destroy = drm_framebuffer_cleanup,
+};
+
+static int sdrm_fbdev_create(struct drm_fb_helper *helper,
+			     struct drm_fb_helper_surface_size *sizes)
+{
+	struct sdrm_fbdev *fbdev = to_sdrm_fbdev(helper);
+	struct drm_device *ddev = helper->dev;
+	struct sdrm_device *sdrm = ddev->dev_private;
+	struct drm_framebuffer *fb = &fbdev->fb;
+	struct drm_mode_fb_cmd2 mode_cmd = {
+		.width = sdrm->fb_width,
+		.height = sdrm->fb_height,
+		.pitches[0] = sdrm->fb_stride,
+		.pixel_format = sdrm->fb_format,
+	};
+	struct fb_info *fbi;
+	int ret;
+
+	fbi = drm_fb_helper_alloc_fbi(helper);
+	if (IS_ERR(fbi))
+		return PTR_ERR(fbi);
+
+	drm_helper_mode_fill_fb_struct(fb, &mode_cmd);
+
+	ret = drm_framebuffer_init(ddev, fb, &sdrm_fb_funcs);
+	if (ret) {
+		dev_err(ddev->dev, "Failed to initialize framebuffer: %d\n", ret);
+		goto err_fb_info_destroy;
+	}
+
+	helper->fb = fb;
+	fbi->par = helper;
+
+	fbi->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE |
+		      FBINFO_CAN_FORCE_OUTPUT;
+	fbi->fbops = &sdrm_fbdev_ops;
+
+	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
+	drm_fb_helper_fill_var(fbi, helper, fb->width, fb->height);
+
+	strncpy(fbi->fix.id, "simpledrmfb", 15);
+	fbi->fix.smem_start = (unsigned long)sdrm->fb_base;
+	fbi->fix.smem_len = sdrm->fb_size;
+	fbi->screen_base = sdrm->fb_map;
+
+	return 0;
+
+err_fb_info_destroy:
+	drm_fb_helper_release_fbi(helper);
+
+	return ret;
+}
+
+static const struct drm_fb_helper_funcs sdrm_fb_helper_funcs = {
+	.fb_probe = sdrm_fbdev_create,
+};
+
+void sdrm_fbdev_init(struct sdrm_device *sdrm)
+{
+	struct drm_device *ddev = sdrm->ddev;
+	struct drm_fb_helper *fb_helper;
+	struct sdrm_fbdev *fbdev;
+	int ret;
+
+	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
+	if (!fbdev) {
+		dev_err(ddev->dev, "Failed to allocate drm fbdev.\n");
+		return;
+	}
+
+	fb_helper = &fbdev->fb_helper;
+
+	drm_fb_helper_prepare(ddev, fb_helper, &sdrm_fb_helper_funcs);
+
+	ret = drm_fb_helper_init(ddev, fb_helper, 1, 1);
+	if (ret < 0) {
+		dev_err(ddev->dev, "Failed to initialize drm fb helper.\n");
+		goto err_free;
+	}
+
+	ret = drm_fb_helper_single_add_all_connectors(fb_helper);
+	if (ret < 0) {
+		dev_err(ddev->dev, "Failed to add connectors.\n");
+		goto err_drm_fb_helper_fini;
+	}
+
+	ret = drm_fb_helper_initial_config(fb_helper,
+					   ddev->mode_config.preferred_depth);
+	if (ret < 0) {
+		dev_err(ddev->dev, "Failed to set initial hw configuration.\n");
+		goto err_drm_fb_helper_fini;
+	}
+
+	sdrm->fbdev = fbdev;
+
+	return;
+
+err_drm_fb_helper_fini:
+	drm_fb_helper_fini(fb_helper);
+err_free:
+	kfree(fbdev);
+}
+
+void sdrm_fbdev_cleanup(struct sdrm_device *sdrm)
+{
+	struct sdrm_fbdev *fbdev = sdrm->fbdev;
+	struct drm_fb_helper *fb_helper;
+
+	if (!fbdev)
+		return;
+
+	sdrm->fbdev = NULL;
+	fb_helper = &fbdev->fb_helper;
+
+	drm_fb_helper_unregister_fbi(fb_helper);
+	drm_fb_helper_release_fbi(fb_helper);
+
+	drm_framebuffer_unregister_private(&fbdev->fb);
+	drm_framebuffer_cleanup(&fbdev->fb);
+
+	drm_fb_helper_fini(fb_helper);
+	kfree(fbdev);
+}
+
+static void sdrm_fbdev_set_suspend(struct fb_info *fbi, int state)
+{
+	console_lock();
+	fb_set_suspend(fbi, state);
+	console_unlock();
+}
+
+/*
+ * Since fbdev is using the native framebuffer, fbcon has to be disabled
+ * when the drm stack is used.
+ */
+void sdrm_fbdev_display_pipe_update(struct sdrm_device *sdrm,
+				    struct drm_framebuffer *fb)
+{
+	struct sdrm_fbdev *fbdev = sdrm->fbdev;
+
+	if (!fbdev || fbdev->fb_helper.fb == fb)
+		return;
+
+	if (fbdev->fb_helper.fbdev->state == FBINFO_STATE_RUNNING)
+		sdrm_fbdev_set_suspend(fbdev->fb_helper.fbdev, 1);
+}
+
+void sdrm_fbdev_restore_mode(struct sdrm_device *sdrm)
+{
+	struct sdrm_fbdev *fbdev = sdrm->fbdev;
+
+	if (!fbdev)
+		return;
+
+	drm_fb_helper_restore_fbdev_mode_unlocked(&fbdev->fb_helper);
+
+	if (fbdev->fb_helper.fbdev->state != FBINFO_STATE_RUNNING)
+		sdrm_fbdev_set_suspend(fbdev->fb_helper.fbdev, 0);
+}
diff --git a/drivers/gpu/drm/simpledrm/simpledrm_kms.c b/drivers/gpu/drm/simpledrm/simpledrm_kms.c
index 00e50d9..92ddc116 100644
--- a/drivers/gpu/drm/simpledrm/simpledrm_kms.c
+++ b/drivers/gpu/drm/simpledrm/simpledrm_kms.c
@@ -24,6 +24,13 @@ static const uint32_t sdrm_formats[] = {
 	DRM_FORMAT_XRGB8888,
 };

+void sdrm_lastclose(struct drm_device *ddev)
+{
+	struct sdrm_device *sdrm = ddev->dev_private;
+
+	sdrm_fbdev_restore_mode(sdrm);
+}
+
 static int sdrm_conn_get_modes(struct drm_connector *conn)
 {
 	struct sdrm_device *sdrm = conn->dev->dev_private;
@@ -91,8 +98,9 @@ void sdrm_display_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct sdrm_device *sdrm = pipe_to_sdrm(pipe);

 	sdrm_crtc_send_vblank_event(&pipe->crtc);
+	sdrm_fbdev_display_pipe_update(sdrm, fb);

-	if (fb) {
+	if (fb && fb->funcs->dirty) {
 		pipe->plane.fb = fb;
 		sdrm_dirty_all_locked(sdrm);
 	}
--
2.8.2

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