drm/kms: driver for virtual cirrus under qemu

This is the initial driver for emulated cirrus GPU found in qemu.
This driver only supports the emulated GPU and doesn't attempt
to bind to any real cirrus GPUs.

This driver is intended to be used with xf86-video-modesetting in userspace.
It requires at least version 0.3.0

This follow the same design as ast and mgag200, and is based on work
done by Matthew Garrett previously.

This GPU has no hw cursor, and it can't scanout 32-bpp, only packed 24-bpp.
i.e. it sucks.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/Kconfig

@@ -190,3 +190,5 @@ source "drivers/gpu/drm/udl/Kconfig"
 source "drivers/gpu/drm/ast/Kconfig"
 
 source "drivers/gpu/drm/mgag200/Kconfig"
+
+source "drivers/gpu/drm/cirrus/Kconfig"

drivers/gpu/drm/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_DRM_MGA)	+= mga/
 obj-$(CONFIG_DRM_I810)	+= i810/
 obj-$(CONFIG_DRM_I915)  += i915/
 obj-$(CONFIG_DRM_MGAG200) += mgag200/
+obj-$(CONFIG_DRM_CIRRUS_QEMU) += cirrus/
 obj-$(CONFIG_DRM_SIS)   += sis/
 obj-$(CONFIG_DRM_SAVAGE)+= savage/
 obj-$(CONFIG_DRM_VMWGFX)+= vmwgfx/

drivers/gpu/drm/cirrus/Kconfig

+config DRM_CIRRUS_QEMU
+	tristate "Cirrus driver for QEMU emulated device"
+	depends on DRM && PCI && EXPERIMENTAL
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	select DRM_KMS_HELPER
+	help
+	 This is a KMS driver for emulated cirrus device in qemu.
+	 It is *NOT* intended for real cirrus devices. This requires
+	 the modesetting userspace X.org driver.

drivers/gpu/drm/cirrus/Makefile

+ccflags-y := -Iinclude/drm
+cirrus-y  := cirrus_main.o cirrus_mode.o \
+	cirrus_drv.o cirrus_fbdev.o cirrus_ttm.o
+
+obj-$(CONFIG_DRM_CIRRUS_QEMU) += cirrus.o

drivers/gpu/drm/cirrus/cirrus_drv.c

+/*
+ * Copyright 2012 Red Hat <mjg@redhat.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License version 2. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Authors: Matthew Garrett
+ *          Dave Airlie
+ */
+#include <linux/module.h>
+#include <linux/console.h>
+#include "drmP.h"
+#include "drm.h"
+
+#include "cirrus_drv.h"
+
+int cirrus_modeset = -1;
+
+MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
+module_param_named(modeset, cirrus_modeset, int, 0400);
+
+/*
+ * This is the generic driver code. This binds the driver to the drm core,
+ * which then performs further device association and calls our graphics init
+ * functions
+ */
+
+static struct drm_driver driver;
+
+/* only bind to the cirrus chip in qemu */
+static DEFINE_PCI_DEVICE_TABLE(pciidlist) = {
+	{ PCI_VENDOR_ID_CIRRUS, PCI_DEVICE_ID_CIRRUS_5446, 0x1af4, 0x1100, 0,
+	  0, 0 },
+	{0,}
+};
+
+static int __devinit
+cirrus_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	return drm_get_pci_dev(pdev, ent, &driver);
+}
+
+static void cirrus_pci_remove(struct pci_dev *pdev)
+{
+	struct drm_device *dev = pci_get_drvdata(pdev);
+
+	drm_put_dev(dev);
+}
+
+static const struct file_operations cirrus_driver_fops = {
+	.owner = THIS_MODULE,
+	.open = drm_open,
+	.release = drm_release,
+	.unlocked_ioctl = drm_ioctl,
+	.mmap = cirrus_mmap,
+	.poll = drm_poll,
+	.fasync = drm_fasync,
+};
+static struct drm_driver driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_USE_MTRR,
+	.load = cirrus_driver_load,
+	.unload = cirrus_driver_unload,
+	.fops = &cirrus_driver_fops,
+	.name = DRIVER_NAME,
+	.desc = DRIVER_DESC,
+	.date = DRIVER_DATE,
+	.major = DRIVER_MAJOR,
+	.minor = DRIVER_MINOR,
+	.patchlevel = DRIVER_PATCHLEVEL,
+	.gem_init_object = cirrus_gem_init_object,
+	.gem_free_object = cirrus_gem_free_object,
+	.dumb_create = cirrus_dumb_create,
+	.dumb_map_offset = cirrus_dumb_mmap_offset,
+	.dumb_destroy = cirrus_dumb_destroy,
+};
+
+static struct pci_driver cirrus_pci_driver = {
+	.name = DRIVER_NAME,
+	.id_table = pciidlist,
+	.probe = cirrus_pci_probe,
+	.remove = cirrus_pci_remove,
+};
+
+static int __init cirrus_init(void)
+{
+	if (vgacon_text_force() && cirrus_modeset == -1)
+		return -EINVAL;
+
+	if (cirrus_modeset == 0)
+		return -EINVAL;
+	return drm_pci_init(&driver, &cirrus_pci_driver);
+}
+
+static void __exit cirrus_exit(void)
+{
+	drm_pci_exit(&driver, &cirrus_pci_driver);
+}
+
+module_init(cirrus_init);
+module_exit(cirrus_exit);
+
+MODULE_DEVICE_TABLE(pci, pciidlist);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");

drivers/gpu/drm/cirrus/cirrus_drv.h

+/*
+ * Copyright 2012 Red Hat
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License version 2. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Authors: Matthew Garrett
+ *          Dave Airlie
+ */
+#ifndef __CIRRUS_DRV_H__
+#define __CIRRUS_DRV_H__
+
+#include <video/vga.h>
+
+#include <drm/drm_fb_helper.h>
+
+#include "ttm/ttm_bo_api.h"
+#include "ttm/ttm_bo_driver.h"
+#include "ttm/ttm_placement.h"
+#include "ttm/ttm_memory.h"
+#include "ttm/ttm_module.h"
+
+#define DRIVER_AUTHOR		"Matthew Garrett"
+
+#define DRIVER_NAME		"cirrus"
+#define DRIVER_DESC		"qemu Cirrus emulation"
+#define DRIVER_DATE		"20110418"
+
+#define DRIVER_MAJOR		1
+#define DRIVER_MINOR		0
+#define DRIVER_PATCHLEVEL	0
+
+#define CIRRUSFB_CONN_LIMIT 1
+
+#define RREG8(reg) ioread8(((void __iomem *)cdev->rmmio) + (reg))
+#define WREG8(reg, v) iowrite8(v, ((void __iomem *)cdev->rmmio) + (reg))
+#define RREG32(reg) ioread32(((void __iomem *)cdev->rmmio) + (reg))
+#define WREG32(reg, v) iowrite32(v, ((void __iomem *)cdev->rmmio) + (reg))
+
+#define SEQ_INDEX 4
+#define SEQ_DATA 5
+
+#define WREG_SEQ(reg, v)					\
+	do {							\
+		WREG8(SEQ_INDEX, reg);				\
+		WREG8(SEQ_DATA, v);				\
+	} while (0)						\
+
+#define CRT_INDEX 0x14
+#define CRT_DATA 0x15
+
+#define WREG_CRT(reg, v)					\
+	do {							\
+		WREG8(CRT_INDEX, reg);				\
+		WREG8(CRT_DATA, v);				\
+	} while (0)						\
+
+#define GFX_INDEX 0xe
+#define GFX_DATA 0xf
+
+#define WREG_GFX(reg, v)					\
+	do {							\
+		WREG8(GFX_INDEX, reg);				\
+		WREG8(GFX_DATA, v);				\
+	} while (0)						\
+
+/*
+ * Cirrus has a "hidden" DAC register that can be accessed by writing to
+ * the pixel mask register to reset the state, then reading from the register
+ * four times. The next write will then pass to the DAC
+ */
+#define VGA_DAC_MASK 0x6
+
+#define WREG_HDR(v)						\
+	do {							\
+		RREG8(VGA_DAC_MASK);					\
+		RREG8(VGA_DAC_MASK);					\
+		RREG8(VGA_DAC_MASK);					\
+		RREG8(VGA_DAC_MASK);					\
+		WREG8(VGA_DAC_MASK, v);					\
+	} while (0)						\
+
+
+#define CIRRUS_MAX_FB_HEIGHT 4096
+#define CIRRUS_MAX_FB_WIDTH 4096
+
+#define CIRRUS_DPMS_CLEARED (-1)
+
+#define to_cirrus_crtc(x) container_of(x, struct cirrus_crtc, base)
+#define to_cirrus_encoder(x) container_of(x, struct cirrus_encoder, base)
+#define to_cirrus_framebuffer(x) container_of(x, struct cirrus_framebuffer, base)
+
+struct cirrus_crtc {
+	struct drm_crtc			base;
+	u8				lut_r[256], lut_g[256], lut_b[256];
+	int				last_dpms;
+	bool				enabled;
+};
+
+struct cirrus_fbdev;
+struct cirrus_mode_info {
+	bool				mode_config_initialized;
+	struct cirrus_crtc		*crtc;
+	/* pointer to fbdev info structure */
+	struct cirrus_fbdev		*gfbdev;
+};
+
+struct cirrus_encoder {
+	struct drm_encoder		base;
+	int				last_dpms;
+};
+
+struct cirrus_connector {
+	struct drm_connector		base;
+};
+
+struct cirrus_framebuffer {
+	struct drm_framebuffer		base;
+	struct drm_gem_object *obj;
+};
+
+struct cirrus_mc {
+	resource_size_t			vram_size;
+	resource_size_t			vram_base;
+};
+
+struct cirrus_device {
+	struct drm_device		*dev;
+	unsigned long			flags;
+
+	resource_size_t			rmmio_base;
+	resource_size_t			rmmio_size;
+	void __iomem			*rmmio;
+
+	struct cirrus_mc			mc;
+	struct cirrus_mode_info		mode_info;
+
+	int				num_crtc;
+	int fb_mtrr;
+
+	struct {
+		struct drm_global_reference mem_global_ref;
+		struct ttm_bo_global_ref bo_global_ref;
+		struct ttm_bo_device bdev;
+		atomic_t validate_sequence;
+	} ttm;
+
+};
+
+
+struct cirrus_fbdev {
+	struct drm_fb_helper helper;
+	struct cirrus_framebuffer gfb;
+	struct list_head fbdev_list;
+	void *sysram;
+	int size;
+};
+
+struct cirrus_bo {
+	struct ttm_buffer_object bo;
+	struct ttm_placement placement;
+	struct ttm_bo_kmap_obj kmap;
+	struct drm_gem_object gem;
+	u32 placements[3];
+	int pin_count;
+};
+#define gem_to_cirrus_bo(gobj) container_of((gobj), struct cirrus_bo, gem)
+
+static inline struct cirrus_bo *
+cirrus_bo(struct ttm_buffer_object *bo)
+{
+	return container_of(bo, struct cirrus_bo, bo);
+}
+
+
+#define to_cirrus_obj(x) container_of(x, struct cirrus_gem_object, base)
+#define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
+
+				/* cirrus_mode.c */
+void cirrus_crtc_fb_gamma_set(struct drm_crtc *crtc, u16 red, u16 green,
+			     u16 blue, int regno);
+void cirrus_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
+			     u16 *blue, int regno);
+
+
+				/* cirrus_main.c */
+int cirrus_device_init(struct cirrus_device *cdev,
+		      struct drm_device *ddev,
+		      struct pci_dev *pdev,
+		      uint32_t flags);
+void cirrus_device_fini(struct cirrus_device *cdev);
+int cirrus_gem_init_object(struct drm_gem_object *obj);
+void cirrus_gem_free_object(struct drm_gem_object *obj);
+int cirrus_dumb_mmap_offset(struct drm_file *file,
+			    struct drm_device *dev,
+			    uint32_t handle,
+			    uint64_t *offset);
+int cirrus_gem_create(struct drm_device *dev,
+		   u32 size, bool iskernel,
+		      struct drm_gem_object **obj);
+int cirrus_dumb_create(struct drm_file *file,
+		    struct drm_device *dev,
+		       struct drm_mode_create_dumb *args);
+int cirrus_dumb_destroy(struct drm_file *file,
+		     struct drm_device *dev,
+			uint32_t handle);
+
+int cirrus_framebuffer_init(struct drm_device *dev,
+			   struct cirrus_framebuffer *gfb,
+			    struct drm_mode_fb_cmd2 *mode_cmd,
+			    struct drm_gem_object *obj);
+
+				/* cirrus_display.c */
+int cirrus_modeset_init(struct cirrus_device *cdev);
+void cirrus_modeset_fini(struct cirrus_device *cdev);
+
+				/* cirrus_fbdev.c */
+int cirrus_fbdev_init(struct cirrus_device *cdev);
+void cirrus_fbdev_fini(struct cirrus_device *cdev);
+
+
+
+				/* cirrus_irq.c */
+void cirrus_driver_irq_preinstall(struct drm_device *dev);
+int cirrus_driver_irq_postinstall(struct drm_device *dev);
+void cirrus_driver_irq_uninstall(struct drm_device *dev);
+irqreturn_t cirrus_driver_irq_handler(DRM_IRQ_ARGS);
+
+				/* cirrus_kms.c */
+int cirrus_driver_load(struct drm_device *dev, unsigned long flags);
+int cirrus_driver_unload(struct drm_device *dev);
+extern struct drm_ioctl_desc cirrus_ioctls[];
+extern int cirrus_max_ioctl;
+
+int cirrus_mm_init(struct cirrus_device *cirrus);
+void cirrus_mm_fini(struct cirrus_device *cirrus);
+void cirrus_ttm_placement(struct cirrus_bo *bo, int domain);
+int cirrus_bo_create(struct drm_device *dev, int size, int align,
+		     uint32_t flags, struct cirrus_bo **pcirrusbo);
+int cirrus_mmap(struct file *filp, struct vm_area_struct *vma);
+int cirrus_bo_reserve(struct cirrus_bo *bo, bool no_wait);
+void cirrus_bo_unreserve(struct cirrus_bo *bo);
+int cirrus_bo_push_sysram(struct cirrus_bo *bo);
+int cirrus_bo_pin(struct cirrus_bo *bo, u32 pl_flag, u64 *gpu_addr);
+#endif				/* __CIRRUS_DRV_H__ */

drivers/gpu/drm/cirrus/cirrus_fbdev.c

+/*
+ * Copyright 2012 Red Hat
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License version 2. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Authors: Matthew Garrett
+ *          Dave Airlie
+ */
+#include <linux/module.h>
+#include "drmP.h"
+#include "drm.h"
+#include "drm_fb_helper.h"
+
+#include <linux/fb.h>
+
+#include "cirrus_drv.h"
+
+static void cirrus_dirty_update(struct cirrus_fbdev *afbdev,
+			     int x, int y, int width, int height)
+{
+	int i;
+	struct drm_gem_object *obj;
+	struct cirrus_bo *bo;
+	int src_offset, dst_offset;
+	int bpp = (afbdev->gfb.base.bits_per_pixel + 7)/8;
+	int ret;
+	bool unmap = false;
+
+	obj = afbdev->gfb.obj;
+	bo = gem_to_cirrus_bo(obj);
+
+	ret = cirrus_bo_reserve(bo, true);
+	if (ret) {
+		DRM_ERROR("failed to reserve fb bo\n");
+		return;
+	}
+
+	if (!bo->kmap.virtual) {
+		ret = ttm_bo_kmap(&bo->bo, 0, bo->bo.num_pages, &bo->kmap);
+		if (ret) {
+			DRM_ERROR("failed to kmap fb updates\n");
+			cirrus_bo_unreserve(bo);
+			return;
+		}
+		unmap = true;
+	}
+	for (i = y; i < y + height; i++) {
+		/* assume equal stride for now */
+		src_offset = dst_offset = i * afbdev->gfb.base.pitches[0] + (x * bpp);
+		memcpy_toio(bo->kmap.virtual + src_offset, afbdev->sysram + src_offset, width * bpp);
+
+	}
+	if (unmap)
+		ttm_bo_kunmap(&bo->kmap);
+
+	cirrus_bo_unreserve(bo);
+}
+
+static void cirrus_fillrect(struct fb_info *info,
+			 const struct fb_fillrect *rect)
+{
+	struct cirrus_fbdev *afbdev = info->par;
+	sys_fillrect(info, rect);
+	cirrus_dirty_update(afbdev, rect->dx, rect->dy, rect->width,
+			 rect->height);
+}
+
+static void cirrus_copyarea(struct fb_info *info,
+			 const struct fb_copyarea *area)
+{
+	struct cirrus_fbdev *afbdev = info->par;
+	sys_copyarea(info, area);
+	cirrus_dirty_update(afbdev, area->dx, area->dy, area->width,
+			 area->height);
+}
+
+static void cirrus_imageblit(struct fb_info *info,
+			  const struct fb_image *image)
+{
+	struct cirrus_fbdev *afbdev = info->par;
+	sys_imageblit(info, image);
+	cirrus_dirty_update(afbdev, image->dx, image->dy, image->width,
+			 image->height);
+}
+
+
+static struct fb_ops cirrusfb_ops = {
+	.owner = THIS_MODULE,
+	.fb_check_var = drm_fb_helper_check_var,
+	.fb_set_par = drm_fb_helper_set_par,
+	.fb_fillrect = cirrus_fillrect,
+	.fb_copyarea = cirrus_copyarea,
+	.fb_imageblit = cirrus_imageblit,
+	.fb_pan_display = drm_fb_helper_pan_display,
+	.fb_blank = drm_fb_helper_blank,
+	.fb_setcmap = drm_fb_helper_setcmap,
+};
+
+static int cirrusfb_create_object(struct cirrus_fbdev *afbdev,
+			       struct drm_mode_fb_cmd2 *mode_cmd,
+			       struct drm_gem_object **gobj_p)
+{
+	struct drm_device *dev = afbdev->helper.dev;
+	u32 bpp, depth;
+	u32 size;
+	struct drm_gem_object *gobj;
+
+	int ret = 0;
+	drm_fb_get_bpp_depth(mode_cmd->pixel_format, &depth, &bpp);
+
+	if (bpp > 24)
+		return -EINVAL;
+	size = mode_cmd->pitches[0] * mode_cmd->height;
+	ret = cirrus_gem_create(dev, size, true, &gobj);
+	if (ret)
+		return ret;
+
+	*gobj_p = gobj;
+	return ret;
+}
+
+static int cirrusfb_create(struct cirrus_fbdev *gfbdev,
+			   struct drm_fb_helper_surface_size *sizes)
+{
+	struct drm_device *dev = gfbdev->helper.dev;
+	struct cirrus_device *cdev = gfbdev->helper.dev->dev_private;
+	struct fb_info *info;
+	struct drm_framebuffer *fb;
+	struct drm_mode_fb_cmd2 mode_cmd;
+	struct device *device = &dev->pdev->dev;
+	void *sysram;
+	struct drm_gem_object *gobj = NULL;
+	struct cirrus_bo *bo = NULL;
+	int size, ret;
+
+	mode_cmd.width = sizes->surface_width;
+	mode_cmd.height = sizes->surface_height;
+	mode_cmd.pitches[0] = mode_cmd.width * ((sizes->surface_bpp + 7) / 8);
+	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
+							  sizes->surface_depth);
+	size = mode_cmd.pitches[0] * mode_cmd.height;
+
+	ret = cirrusfb_create_object(gfbdev, &mode_cmd, &gobj);
+	if (ret) {
+		DRM_ERROR("failed to create fbcon backing object %d\n", ret);
+		return ret;
+	}
+
+	bo = gem_to_cirrus_bo(gobj);
+
+	sysram = vmalloc(size);
+	if (!sysram)
+		return -ENOMEM;
+
+	info = framebuffer_alloc(0, device);
+	if (info == NULL)
+		return -ENOMEM;
+
+	info->par = gfbdev;
+
+	ret = cirrus_framebuffer_init(cdev->dev, &gfbdev->gfb, &mode_cmd, gobj);
+	if (ret)
+		return ret;
+
+	gfbdev->sysram = sysram;
+	gfbdev->size = size;
+
+	fb = &gfbdev->gfb.base;
+	if (!fb) {
+		DRM_INFO("fb is NULL\n");
+		return -EINVAL;
+	}
+
+	/* setup helper */
+	gfbdev->helper.fb = fb;
+	gfbdev->helper.fbdev = info;
+
+	strcpy(info->fix.id, "cirrusdrmfb");
+
+
+	info->flags = FBINFO_DEFAULT;
+	info->fbops = &cirrusfb_ops;
+
+	drm_fb_helper_fill_fix(info, fb->pitches[0], fb->depth);
+	drm_fb_helper_fill_var(info, &gfbdev->helper, sizes->fb_width,
+			       sizes->fb_height);
+
+	/* setup aperture base/size for vesafb takeover */
+	info->apertures = alloc_apertures(1);
+	if (!info->apertures) {
+		ret = -ENOMEM;
+		goto out_iounmap;
+	}
+	info->apertures->ranges[0].base = cdev->dev->mode_config.fb_base;
+	info->apertures->ranges[0].size = cdev->mc.vram_size;
+
+	info->screen_base = sysram;
+	info->screen_size = size;
+
+	info->fix.mmio_start = 0;
+	info->fix.mmio_len = 0;
+
+	ret = fb_alloc_cmap(&info->cmap, 256, 0);
+	if (ret) {
+		DRM_ERROR("%s: can't allocate color map\n", info->fix.id);
+		ret = -ENOMEM;
+		goto out_iounmap;
+	}
+
+	DRM_INFO("fb mappable at 0x%lX\n", info->fix.smem_start);
+	DRM_INFO("vram aper at 0x%lX\n", (unsigned long)info->fix.smem_start);
+	DRM_INFO("size %lu\n", (unsigned long)info->fix.smem_len);
+	DRM_INFO("fb depth is %d\n", fb->depth);
+	DRM_INFO("   pitch is %d\n", fb->pitches[0]);
+
+	return 0;
+out_iounmap:
+	return ret;
+}
+
+static int cirrus_fb_find_or_create_single(struct drm_fb_helper *helper,
+					   struct drm_fb_helper_surface_size
+					   *sizes)
+{
+	struct cirrus_fbdev *gfbdev = (struct cirrus_fbdev *)helper;
+	int new_fb = 0;
+	int ret;
+
+	if (!helper->fb) {
+		ret = cirrusfb_create(gfbdev, sizes);
+		if (ret)
+			return ret;
+		new_fb = 1;
+	}
+	return new_fb;
+}
+
+static int cirrus_fbdev_destroy(struct drm_device *dev,
+				struct cirrus_fbdev *gfbdev)
+{
+	struct fb_info *info;
+	struct cirrus_framebuffer *gfb = &gfbdev->gfb;
+
+	if (gfbdev->helper.fbdev) {
+		info = gfbdev->helper.fbdev;
+
+		unregister_framebuffer(info);
+		if (info->cmap.len)
+			fb_dealloc_cmap(&info->cmap);
+		framebuffer_release(info);
+	}
+
+	if (gfb->obj) {
+		drm_gem_object_unreference_unlocked(gfb->obj);
+		gfb->obj = NULL;
+	}
+
+	vfree(gfbdev->sysram);
+	drm_fb_helper_fini(&gfbdev->helper);
+	drm_framebuffer_cleanup(&gfb->base);
+
+	return 0;
+}
+
+static struct drm_fb_helper_funcs cirrus_fb_helper_funcs = {
+	.gamma_set = cirrus_crtc_fb_gamma_set,
+	.gamma_get = cirrus_crtc_fb_gamma_get,
+	.fb_probe = cirrus_fb_find_or_create_single,
+};
+
+int cirrus_fbdev_init(struct cirrus_device *cdev)
+{
+	struct cirrus_fbdev *gfbdev;
+	int ret;
+	int bpp_sel = 24;
+
+	/*bpp_sel = 8;*/
+	gfbdev = kzalloc(sizeof(struct cirrus_fbdev), GFP_KERNEL);
+	if (!gfbdev)
+		return -ENOMEM;
+
+	cdev->mode_info.gfbdev = gfbdev;
+	gfbdev->helper.funcs = &cirrus_fb_helper_funcs;
+
+	ret = drm_fb_helper_init(cdev->dev, &gfbdev->helper,
+				 cdev->num_crtc, CIRRUSFB_CONN_LIMIT);
+	if (ret) {
+		kfree(gfbdev);
+		return ret;
+	}
+	drm_fb_helper_single_add_all_connectors(&gfbdev->helper);
+	drm_fb_helper_initial_config(&gfbdev->helper, bpp_sel);
+
+	return 0;
+}
+
+void cirrus_fbdev_fini(struct cirrus_device *cdev)
+{
+	if (!cdev->mode_info.gfbdev)
+		return;
+
+	cirrus_fbdev_destroy(cdev->dev, cdev->mode_info.gfbdev);
+	kfree(cdev->mode_info.gfbdev);
+	cdev->mode_info.gfbdev = NULL;
+}

drivers/gpu/drm/cirrus/cirrus_main.c

+/*
+ * Copyright 2012 Red Hat
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License version 2. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Authors: Matthew Garrett
+ *          Dave Airlie
+ */
+#include "drmP.h"
+#include "drm.h"
+#include "drm_crtc_helper.h"
+
+#include "cirrus_drv.h"
+
+
+static void cirrus_user_framebuffer_destroy(struct drm_framebuffer *fb)
+{
+	struct cirrus_framebuffer *cirrus_fb = to_cirrus_framebuffer(fb);
+	if (cirrus_fb->obj)
+		drm_gem_object_unreference_unlocked(cirrus_fb->obj);
+	drm_framebuffer_cleanup(fb);
+	kfree(fb);
+}
+
+static int cirrus_user_framebuffer_create_handle(struct drm_framebuffer *fb,
+						 struct drm_file *file_priv,
+						 unsigned int *handle)
+{
+	return 0;
+}
+
+static const struct drm_framebuffer_funcs cirrus_fb_funcs = {
+	.destroy = cirrus_user_framebuffer_destroy,
+	.create_handle = cirrus_user_framebuffer_create_handle,
+};
+
+int cirrus_framebuffer_init(struct drm_device *dev,
+			    struct cirrus_framebuffer *gfb,
+			    struct drm_mode_fb_cmd2 *mode_cmd,
+			    struct drm_gem_object *obj)
+{
+	int ret;
+
+	ret = drm_framebuffer_init(dev, &gfb->base, &cirrus_fb_funcs);
+	if (ret) {
+		DRM_ERROR("drm_framebuffer_init failed: %d\n", ret);
+		return ret;
+	}
+	drm_helper_mode_fill_fb_struct(&gfb->base, mode_cmd);
+	gfb->obj = obj;
+	return 0;
+}
+
+static struct drm_framebuffer *
+cirrus_user_framebuffer_create(struct drm_device *dev,
+			       struct drm_file *filp,
+			       struct drm_mode_fb_cmd2 *mode_cmd)
+{
+	struct drm_gem_object *obj;
+	struct cirrus_framebuffer *cirrus_fb;
+	int ret;
+	u32 bpp, depth;
+
+	drm_fb_get_bpp_depth(mode_cmd->pixel_format, &depth, &bpp);
+	/* cirrus can't handle > 24bpp framebuffers at all */
+	if (bpp > 24)
+		return ERR_PTR(-EINVAL);
+
+	obj = drm_gem_object_lookup(dev, filp, mode_cmd->handles[0]);
+	if (obj == NULL)
+		return ERR_PTR(-ENOENT);
+
+	cirrus_fb = kzalloc(sizeof(*cirrus_fb), GFP_KERNEL);
+	if (!cirrus_fb) {
+		drm_gem_object_unreference_unlocked(obj);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	ret = cirrus_framebuffer_init(dev, cirrus_fb, mode_cmd, obj);
+	if (ret) {
+		drm_gem_object_unreference_unlocked(obj);
+		kfree(cirrus_fb);
+		return ERR_PTR(ret);
+	}
+	return &cirrus_fb->base;
+}
+
+static const struct drm_mode_config_funcs cirrus_mode_funcs = {
+	.fb_create = cirrus_user_framebuffer_create,
+};
+
+/* Unmap the framebuffer from the core and release the memory */
+static void cirrus_vram_fini(struct cirrus_device *cdev)
+{
+	iounmap(cdev->rmmio);
+	cdev->rmmio = NULL;
+	if (cdev->mc.vram_base)
+		release_mem_region(cdev->mc.vram_base, cdev->mc.vram_size);
+}
+
+/* Map the framebuffer from the card and configure the core */
+static int cirrus_vram_init(struct cirrus_device *cdev)
+{
+	/* BAR 0 is VRAM */
+	cdev->mc.vram_base = pci_resource_start(cdev->dev->pdev, 0);
+	/* We have 4MB of VRAM */
+	cdev->mc.vram_size = 4 * 1024 * 1024;
+
+	if (!request_mem_region(cdev->mc.vram_base, cdev->mc.vram_size,
+				"cirrusdrmfb_vram")) {
+		DRM_ERROR("can't reserve VRAM\n");
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+/*
+ * Our emulated hardware has two sets of memory. One is video RAM and can
+ * simply be used as a linear framebuffer - the other provides mmio access
+ * to the display registers. The latter can also be accessed via IO port
+ * access, but we map the range and use mmio to program them instead
+ */
+
+int cirrus_device_init(struct cirrus_device *cdev,
+		       struct drm_device *ddev,
+		       struct pci_dev *pdev, uint32_t flags)
+{
+	int ret;
+
+	cdev->dev = ddev;
+	cdev->flags = flags;
+
+	/* Hardcode the number of CRTCs to 1 */
+	cdev->num_crtc = 1;
+
+	/* BAR 0 is the framebuffer, BAR 1 contains registers */
+	cdev->rmmio_base = pci_resource_start(cdev->dev->pdev, 1);
+	cdev->rmmio_size = pci_resource_len(cdev->dev->pdev, 1);
+
+	if (!request_mem_region(cdev->rmmio_base, cdev->rmmio_size,
+				"cirrusdrmfb_mmio")) {
+		DRM_ERROR("can't reserve mmio registers\n");
+		return -ENOMEM;
+	}
+
+	cdev->rmmio = ioremap(cdev->rmmio_base, cdev->rmmio_size);
+
+	if (cdev->rmmio == NULL)
+		return -ENOMEM;
+
+	ret = cirrus_vram_init(cdev);
+	if (ret) {
+		release_mem_region(cdev->rmmio_base, cdev->rmmio_size);
+		return ret;
+	}
+
+	return 0;
+}
+
+void cirrus_device_fini(struct cirrus_device *cdev)
+{
+	release_mem_region(cdev->rmmio_base, cdev->rmmio_size);
+	cirrus_vram_fini(cdev);
+}
+
+/*
+ * Functions here will be called by the core once it's bound the driver to
+ * a PCI device
+ */
+
+int cirrus_driver_load(struct drm_device *dev, unsigned long flags)
+{
+	struct cirrus_device *cdev;
+	int r;
+
+	cdev = kzalloc(sizeof(struct cirrus_device), GFP_KERNEL);
+	if (cdev == NULL)
+		return -ENOMEM;
+	dev->dev_private = (void *)cdev;
+
+	r = cirrus_device_init(cdev, dev, dev->pdev, flags);
+	if (r) {
+		dev_err(&dev->pdev->dev, "Fatal error during GPU init: %d\n", r);
+		goto out;
+	}
+
+	r = cirrus_mm_init(cdev);
+	if (r)
+		dev_err(&dev->pdev->dev, "fatal err on mm init\n");
+
+	r = cirrus_modeset_init(cdev);
+	if (r)
+		dev_err(&dev->pdev->dev, "Fatal error during modeset init: %d\n", r);
+
+	dev->mode_config.funcs = (void *)&cirrus_mode_funcs;
+out:
+	if (r)
+		cirrus_driver_unload(dev);
+	return r;
+}
+
+int cirrus_driver_unload(struct drm_device *dev)
+{
+	struct cirrus_device *cdev = dev->dev_private;
+
+	if (cdev == NULL)
+		return 0;
+	cirrus_modeset_fini(cdev);
+	cirrus_mm_fini(cdev);
+	cirrus_device_fini(cdev);
+	kfree(cdev);
+	dev->dev_private = NULL;
+	return 0;
+}
+
+int cirrus_gem_create(struct drm_device *dev,
+		   u32 size, bool iskernel,
+		   struct drm_gem_object **obj)
+{
+	struct cirrus_bo *cirrusbo;
+	int ret;
+
+	*obj = NULL;
+
+	size = roundup(size, PAGE_SIZE);
+	if (size == 0)
+		return -EINVAL;
+
+	ret = cirrus_bo_create(dev, size, 0, 0, &cirrusbo);
+	if (ret) {
+		if (ret != -ERESTARTSYS)
+			DRM_ERROR("failed to allocate GEM object\n");
+		return ret;
+	}
+	*obj = &cirrusbo->gem;
+	return 0;
+}
+
+int cirrus_dumb_create(struct drm_file *file,
+		    struct drm_device *dev,
+		    struct drm_mode_create_dumb *args)
+{
+	int ret;
+	struct drm_gem_object *gobj;
+	u32 handle;
+
+	args->pitch = args->width * ((args->bpp + 7) / 8);
+	args->size = args->pitch * args->height;
+
+	ret = cirrus_gem_create(dev, args->size, false,
+			     &gobj);
+	if (ret)
+		return ret;
+
+	ret = drm_gem_handle_create(file, gobj, &handle);
+	drm_gem_object_unreference_unlocked(gobj);
+	if (ret)
+		return ret;
+
+	args->handle = handle;
+	return 0;
+}
+
+int cirrus_dumb_destroy(struct drm_file *file,
+		     struct drm_device *dev,
+		     uint32_t handle)
+{
+	return drm_gem_handle_delete(file, handle);
+}
+
+int cirrus_gem_init_object(struct drm_gem_object *obj)
+{
+	BUG();
+	return 0;
+}
+
+void cirrus_bo_unref(struct cirrus_bo **bo)
+{
+	struct ttm_buffer_object *tbo;
+
+	if ((*bo) == NULL)
+		return;
+
+	tbo = &((*bo)->bo);
+	ttm_bo_unref(&tbo);
+	if (tbo == NULL)
+		*bo = NULL;
+
+}
+
+void cirrus_gem_free_object(struct drm_gem_object *obj)
+{
+	struct cirrus_bo *cirrus_bo = gem_to_cirrus_bo(obj);
+
+	if (!cirrus_bo)
+		return;
+	cirrus_bo_unref(&cirrus_bo);
+}
+
+
+static inline u64 cirrus_bo_mmap_offset(struct cirrus_bo *bo)
+{
+	return bo->bo.addr_space_offset;
+}
+
+int
+cirrus_dumb_mmap_offset(struct drm_file *file,
+		     struct drm_device *dev,
+		     uint32_t handle,
+		     uint64_t *offset)
+{
+	struct drm_gem_object *obj;
+	int ret;
+	struct cirrus_bo *bo;
+
+	mutex_lock(&dev->struct_mutex);
+	obj = drm_gem_object_lookup(dev, file, handle);
+	if (obj == NULL) {
+		ret = -ENOENT;
+		goto out_unlock;
+	}
+
+	bo = gem_to_cirrus_bo(obj);
+	*offset = cirrus_bo_mmap_offset(bo);
+
+	drm_gem_object_unreference(obj);
+	ret = 0;
+out_unlock:
+	mutex_unlock(&dev->struct_mutex);
+	return ret;
+
+}