drm/vc4: Add KMS support for Raspberry Pi.

This is enough for fbcon and bringing up X using
xf86-video-modesetting.  It doesn't support the 3D accelerator or
power management yet.

v2: Drop FB_HELPER select thanks to Archit's patches.  Do manual init
    ordering instead of using the .load hook.  Structure registration
    more like tegra's, but still using the typical "component" code.
    Drop no-op hooks for atomic_begin and mode_fixup() now that
    they're optional.  Drop sentinel in Makefile.  Fix minor style
    nits I noticed on another reread.

v3: Use the new bcm2835 clk driver to manage pixel/HSM clocks instead
    of having a fixed video mode.  Use exynos-style component driver
    matching instead of devicetree nodes to list the component driver
    instances.  Rename compatibility strings to say bcm2835, and
    distinguish pv0/1/2.  Clean up some h/vsync code, and add in
    interlaced mode setup.  Fix up probe/bind error paths.  Use
    bitops.h macros for vc4_regs.h

v4: Include i2c.h, allow building under COMPILE_TEST, drop msleep now
    that other bugs have been fixed, add timeouts to cpu_relax()
    loops, rename hpd-gpio to hpd-gpios.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/Kconfig

@@ -264,3 +264,5 @@ source "drivers/gpu/drm/sti/Kconfig"
 source "drivers/gpu/drm/amd/amdkfd/Kconfig"
 
 source "drivers/gpu/drm/imx/Kconfig"
+
+source "drivers/gpu/drm/vc4/Kconfig"

drivers/gpu/drm/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_DRM_MGA)	+= mga/
 obj-$(CONFIG_DRM_I810)	+= i810/
 obj-$(CONFIG_DRM_I915)  += i915/
 obj-$(CONFIG_DRM_MGAG200) += mgag200/
+obj-$(CONFIG_DRM_VC4)  += vc4/
 obj-$(CONFIG_DRM_CIRRUS_QEMU) += cirrus/
 obj-$(CONFIG_DRM_SIS)   += sis/
 obj-$(CONFIG_DRM_SAVAGE)+= savage/

drivers/gpu/drm/vc4/Kconfig

@@ -0,0 +1,13 @@
+config DRM_VC4
+	tristate "Broadcom VC4 Graphics"
+	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_CMA_HELPER
+	help
+	  Choose this option if you have a system that has a Broadcom
+	  VC4 GPU, such as the Raspberry Pi or other BCM2708/BCM2835.
+
+	  This driver requires that "avoid_warnings=2" be present in
+	  the config.txt for the firmware, to keep it from smashing
+	  our display setup.

drivers/gpu/drm/vc4/Makefile

@@ -0,0 +1,17 @@
+ccflags-y := -Iinclude/drm
+
+# Please keep these build lists sorted!
+
+# core driver code
+vc4-y := \
+	vc4_bo.o \
+	vc4_crtc.o \
+	vc4_drv.o \
+	vc4_kms.o \
+	vc4_hdmi.o \
+	vc4_hvs.o \
+	vc4_plane.o
+
+vc4-$(CONFIG_DEBUG_FS) += vc4_debugfs.o
+
+obj-$(CONFIG_DRM_VC4)  += vc4.o

drivers/gpu/drm/vc4/vc4_bo.c

@@ -0,0 +1,52 @@
+/*
+ *  Copyright © 2015 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/* DOC: VC4 GEM BO management support.
+ *
+ * The VC4 GPU architecture (both scanout and rendering) has direct
+ * access to system memory with no MMU in between.  To support it, we
+ * use the GEM CMA helper functions to allocate contiguous ranges of
+ * physical memory for our BOs.
+ */
+
+#include "vc4_drv.h"
+
+struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size)
+{
+	struct drm_gem_cma_object *cma_obj;
+
+	cma_obj = drm_gem_cma_create(dev, size);
+	if (IS_ERR(cma_obj))
+		return NULL;
+	else
+		return to_vc4_bo(&cma_obj->base);
+}
+
+int vc4_dumb_create(struct drm_file *file_priv,
+		    struct drm_device *dev,
+		    struct drm_mode_create_dumb *args)
+{
+	int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+	struct vc4_bo *bo = NULL;
+	int ret;
+
+	if (args->pitch < min_pitch)
+		args->pitch = min_pitch;
+
+	if (args->size < args->pitch * args->height)
+		args->size = args->pitch * args->height;
+
+	bo = vc4_bo_create(dev, roundup(args->size, PAGE_SIZE));
+	if (!bo)
+		return -ENOMEM;
+
+	ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
+	drm_gem_object_unreference_unlocked(&bo->base.base);
+
+	return ret;
+}