DRM: Add DRM KMS/FB CMA helper

This patchset introduces a set of helper function for implementing the KMS
framebuffer layer for drivers which use the DRM GEM CMA helper function.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
[Make DRM_KMS_CMA_HELPER a boolean Kconfig option]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/Kconfig

@@ -60,6 +60,15 @@ config DRM_GEM_CMA_HELPER
 	help
 	  Choose this if you need the GEM CMA helper functions
 
+config DRM_KMS_CMA_HELPER
+	bool
+	select DRM_GEM_CMA_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	help
+	  Choose this if you need the KMS CMA helper functions
+
 config DRM_TDFX
 	tristate "3dfx Banshee/Voodoo3+"
 	depends on DRM && PCI

drivers/gpu/drm/Makefile

@@ -21,6 +21,7 @@ drm-usb-y   := drm_usb.o
 
 drm_kms_helper-y := drm_fb_helper.o drm_crtc_helper.o drm_dp_i2c_helper.o
 drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
 

drivers/gpu/drm/drm_fb_cma_helper.c

+/*
+ * drm kms/fb cma (contiguous memory allocator) helper functions
+ *
+ * Copyright (C) 2012 Analog Device Inc.
+ *   Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * Based on udl_fbdev.c
+ *  Copyright (C) 2012 Red Hat
+ *
+ * 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.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+#include <linux/module.h>
+
+struct drm_fb_cma {
+	struct drm_framebuffer		fb;
+	struct drm_gem_cma_object	*obj[4];
+};
+
+struct drm_fbdev_cma {
+	struct drm_fb_helper	fb_helper;
+	struct drm_fb_cma	*fb;
+};
+
+static inline struct drm_fbdev_cma *to_fbdev_cma(struct drm_fb_helper *helper)
+{
+	return container_of(helper, struct drm_fbdev_cma, fb_helper);
+}
+
+static inline struct drm_fb_cma *to_fb_cma(struct drm_framebuffer *fb)
+{
+	return container_of(fb, struct drm_fb_cma, fb);
+}
+
+static void drm_fb_cma_destroy(struct drm_framebuffer *fb)
+{
+	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		if (fb_cma->obj[i])
+			drm_gem_object_unreference_unlocked(&fb_cma->obj[i]->base);
+	}
+
+	drm_framebuffer_cleanup(fb);
+	kfree(fb_cma);
+}
+
+static int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
+	struct drm_file *file_priv, unsigned int *handle)
+{
+	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
+
+	return drm_gem_handle_create(file_priv,
+			&fb_cma->obj[0]->base, handle);
+}
+
+static struct drm_framebuffer_funcs drm_fb_cma_funcs = {
+	.destroy	= drm_fb_cma_destroy,
+	.create_handle	= drm_fb_cma_create_handle,
+};
+
+static struct drm_fb_cma *drm_fb_cma_alloc(struct drm_device *dev,
+	struct drm_mode_fb_cmd2 *mode_cmd, struct drm_gem_cma_object **obj,
+	unsigned int num_planes)
+{
+	struct drm_fb_cma *fb_cma;
+	int ret;
+	int i;
+
+	fb_cma = kzalloc(sizeof(*fb_cma), GFP_KERNEL);
+	if (!fb_cma)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drm_framebuffer_init(dev, &fb_cma->fb, &drm_fb_cma_funcs);
+	if (ret) {
+		dev_err(dev->dev, "Failed to initalize framebuffer: %d\n", ret);
+		kfree(fb_cma);
+		return ERR_PTR(ret);
+	}
+
+	drm_helper_mode_fill_fb_struct(&fb_cma->fb, mode_cmd);
+
+	for (i = 0; i < num_planes; i++)
+		fb_cma->obj[i] = obj[i];
+
+	return fb_cma;
+}
+
+/**
+ * drm_fb_cma_create() - (struct drm_mode_config_funcs *)->fb_create callback function
+ *
+ * If your hardware has special alignment or pitch requirements these should be
+ * checked before calling this function.
+ */
+struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
+	struct drm_file *file_priv, struct drm_mode_fb_cmd2 *mode_cmd)
+{
+	struct drm_fb_cma *fb_cma;
+	struct drm_gem_cma_object *objs[4];
+	struct drm_gem_object *obj;
+	unsigned int hsub;
+	unsigned int vsub;
+	int ret;
+	int i;
+
+	hsub = drm_format_horz_chroma_subsampling(mode_cmd->pixel_format);
+	vsub = drm_format_vert_chroma_subsampling(mode_cmd->pixel_format);
+
+	for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
+		unsigned int width = mode_cmd->width / (i ? hsub : 1);
+		unsigned int height = mode_cmd->height / (i ? vsub : 1);
+		unsigned int min_size;
+
+		obj = drm_gem_object_lookup(dev, file_priv, mode_cmd->handles[i]);
+		if (!obj) {
+			dev_err(dev->dev, "Failed to lookup GEM object\n");
+			ret = -ENXIO;
+			goto err_gem_object_unreference;
+		}
+
+		min_size = (height - 1) * mode_cmd->pitches[i]
+			 + width * drm_format_plane_cpp(mode_cmd->pixel_format, i)
+			 + mode_cmd->offsets[i];
+
+		if (obj->size < min_size) {
+			drm_gem_object_unreference_unlocked(obj);
+			ret = -EINVAL;
+			goto err_gem_object_unreference;
+		}
+		objs[i] = to_drm_gem_cma_obj(obj);
+	}
+
+	fb_cma = drm_fb_cma_alloc(dev, mode_cmd, objs, i);
+	if (IS_ERR(fb_cma)) {
+		ret = PTR_ERR(fb_cma);
+		goto err_gem_object_unreference;
+	}
+
+	return &fb_cma->fb;
+
+err_gem_object_unreference:
+	for (i--; i >= 0; i--)
+		drm_gem_object_unreference_unlocked(&objs[i]->base);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_create);
+
+/**
+ * drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
+ * @fb: The framebuffer
+ * @plane: Which plane
+ *
+ * Return the CMA GEM object for given framebuffer.
+ *
+ * This function will usually be called from the CRTC callback functions.
+ */
+struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
+	unsigned int plane)
+{
+	struct drm_fb_cma *fb_cma = to_fb_cma(fb);
+
+	if (plane >= 4)
+		return NULL;
+
+	return fb_cma->obj[plane];
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
+
+static struct fb_ops drm_fbdev_cma_ops = {
+	.owner		= THIS_MODULE,
+	.fb_fillrect	= sys_fillrect,
+	.fb_copyarea	= sys_copyarea,
+	.fb_imageblit	= sys_imageblit,
+	.fb_check_var	= drm_fb_helper_check_var,
+	.fb_set_par	= drm_fb_helper_set_par,
+	.fb_blank	= drm_fb_helper_blank,
+	.fb_pan_display	= drm_fb_helper_pan_display,
+	.fb_setcmap	= drm_fb_helper_setcmap,
+};
+
+static int drm_fbdev_cma_create(struct drm_fb_helper *helper,
+	struct drm_fb_helper_surface_size *sizes)
+{
+	struct drm_fbdev_cma *fbdev_cma = to_fbdev_cma(helper);
+	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
+	struct drm_device *dev = helper->dev;
+	struct drm_gem_cma_object *obj;
+	struct drm_framebuffer *fb;
+	unsigned int bytes_per_pixel;
+	unsigned long offset;
+	struct fb_info *fbi;
+	size_t size;
+	int ret;
+
+	DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d\n",
+			sizes->surface_width, sizes->surface_height,
+			sizes->surface_bpp);
+
+	bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);
+
+	mode_cmd.width = sizes->surface_width;
+	mode_cmd.height = sizes->surface_height;
+	mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
+	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
+		sizes->surface_depth);
+
+	size = mode_cmd.pitches[0] * mode_cmd.height;
+	obj = drm_gem_cma_create(dev, size);
+	if (!obj)
+		return -ENOMEM;
+
+	fbi = framebuffer_alloc(0, dev->dev);
+	if (!fbi) {
+		dev_err(dev->dev, "Failed to allocate framebuffer info.\n");
+		ret = -ENOMEM;
+		goto err_drm_gem_cma_free_object;
+	}
+
+	fbdev_cma->fb = drm_fb_cma_alloc(dev, &mode_cmd, &obj, 1);
+	if (IS_ERR(fbdev_cma->fb)) {
+		dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
+		ret = PTR_ERR(fbdev_cma->fb);
+		goto err_framebuffer_release;
+	}
+
+	fb = &fbdev_cma->fb->fb;
+	helper->fb = fb;
+	helper->fbdev = fbi;
+
+	fbi->par = helper;
+	fbi->flags = FBINFO_FLAG_DEFAULT;
+	fbi->fbops = &drm_fbdev_cma_ops;
+
+	ret = fb_alloc_cmap(&fbi->cmap, 256, 0);
+	if (ret) {
+		dev_err(dev->dev, "Failed to allocate color map.\n");
+		goto err_drm_fb_cma_destroy;
+	}
+
+	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
+	drm_fb_helper_fill_var(fbi, helper, fb->width, fb->height);
+
+	offset = fbi->var.xoffset * bytes_per_pixel;
+	offset += fbi->var.yoffset * fb->pitches[0];
+
+	dev->mode_config.fb_base = (resource_size_t)obj->paddr;
+	fbi->screen_base = obj->vaddr + offset;
+	fbi->fix.smem_start = (unsigned long)(obj->paddr + offset);
+	fbi->screen_size = size;
+	fbi->fix.smem_len = size;
+
+	return 0;
+
+err_drm_fb_cma_destroy:
+	drm_fb_cma_destroy(fb);
+err_framebuffer_release:
+	framebuffer_release(fbi);
+err_drm_gem_cma_free_object:
+	drm_gem_cma_free_object(&obj->base);
+	return ret;
+}
+
+static int drm_fbdev_cma_probe(struct drm_fb_helper *helper,
+	struct drm_fb_helper_surface_size *sizes)
+{
+	int ret = 0;
+
+	if (!helper->fb) {
+		ret = drm_fbdev_cma_create(helper, sizes);
+		if (ret < 0)
+			return ret;
+		ret = 1;
+	}
+
+	return ret;
+}
+
+static struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
+	.fb_probe = drm_fbdev_cma_probe,
+};
+
+/**
+ * drm_fbdev_cma_init() - Allocate and initializes a drm_fbdev_cma struct
+ * @dev: DRM device
+ * @preferred_bpp: Preferred bits per pixel for the device
+ * @num_crtc: Number of CRTCs
+ * @max_conn_count: Maximum number of connectors
+ *
+ * Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
+ */
+struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
+	unsigned int preferred_bpp, unsigned int num_crtc,
+	unsigned int max_conn_count)
+{
+	struct drm_fbdev_cma *fbdev_cma;
+	struct drm_fb_helper *helper;
+	int ret;
+
+	fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
+	if (!fbdev_cma) {
+		dev_err(dev->dev, "Failed to allocate drm fbdev.\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	fbdev_cma->fb_helper.funcs = &drm_fb_cma_helper_funcs;
+	helper = &fbdev_cma->fb_helper;
+
+	ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
+		goto err_free;
+	}
+
+	ret = drm_fb_helper_single_add_all_connectors(helper);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to add connectors.\n");
+		goto err_drm_fb_helper_fini;
+
+	}
+
+	ret = drm_fb_helper_initial_config(helper, preferred_bpp);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to set inital hw configuration.\n");
+		goto err_drm_fb_helper_fini;
+	}
+
+	return fbdev_cma;
+
+err_drm_fb_helper_fini:
+	drm_fb_helper_fini(helper);
+err_free:
+	kfree(fbdev_cma);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);
+
+/**
+ * drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
+ * @fbdev_cma: The drm_fbdev_cma struct
+ */
+void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
+{
+	if (fbdev_cma->fb_helper.fbdev) {
+		struct fb_info *info;
+		int ret;
+
+		info = fbdev_cma->fb_helper.fbdev;
+		ret = unregister_framebuffer(info);
+		if (ret < 0)
+			DRM_DEBUG_KMS("failed unregister_framebuffer()\n");
+
+		if (info->cmap.len)
+			fb_dealloc_cmap(&info->cmap);
+
+		framebuffer_release(info);
+	}
+
+	if (fbdev_cma->fb)
+		drm_fb_cma_destroy(&fbdev_cma->fb->fb);
+
+	drm_fb_helper_fini(&fbdev_cma->fb_helper);
+	kfree(fbdev_cma);
+}
+EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);
+
+/**
+ * drm_fbdev_cma_restore_mode() - Restores initial framebuffer mode
+ * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
+ *
+ * This function is usually called from the DRM drivers lastclose callback.
+ */
+void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
+{
+	if (fbdev_cma)
+		drm_fb_helper_restore_fbdev_mode(&fbdev_cma->fb_helper);
+}
+EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);
+
+/**
+ * drm_fbdev_cma_hotplug_event() - Poll for hotpulug events
+ * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
+ *
+ * This function is usually called from the DRM drivers output_poll_changed
+ * callback.
+ */
+void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
+{
+	if (fbdev_cma)
+		drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
+}
+EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);

include/drm/drm_fb_cma_helper.h

+#ifndef __DRM_FB_CMA_HELPER_H__
+#define __DRM_FB_CMA_HELPER_H__
+
+struct drm_fbdev_cma;
+struct drm_gem_cma_object;
+
+struct drm_framebuffer;
+struct drm_device;
+struct drm_file;
+struct drm_mode_fb_cmd2;
+
+struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
+	unsigned int preferred_bpp, unsigned int num_crtc,
+	unsigned int max_conn_count);
+void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma);
+
+void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma);
+void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma);
+
+struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
+	struct drm_file *file_priv, struct drm_mode_fb_cmd2 *mode_cmd);
+
+struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
+	unsigned int plane);
+
+#endif
+