Re: [PATCH v5 4/7] video: add generic framebuffer eviction

Hi

On Sat, Sep 3, 2016 at 2:06 PM, Noralf Trønnes noralf@tronnes.org wrote:

Den 02.09.2016 10:22, skrev David Herrmann:

...

There are several situations where we want hardware handover from an early boot GFX driver (e.g., vgacon, vesafb, efifb, simplefb) to a full fletched GFX driver (e.g., most DRM drivers). So far, we relied on remove_conflicting_framebuffers() to do this for us, however, this had a bunch of downsides:

o It only removes conflicting fbdev drivers. It does not drop vgacon, early boot console drivers, conflicting DRM drivers, etc.

o It only unloads the fbdev driver, it does not modify the underlying device or resources. In case of "screen_info" drivers (e.g., efifb) this is fine, since no resources are pinned. However, if the driver binds to a platform-device like "simple-framebuffer", we must make sure to unregister that device as well. Otherwise, pinned resources like IORESOURCE_MEM stay around, triggering WARN_ONs if the following driver requests those resources.

o It is only available if CONFIG_FB is selected.

This commit adds a new infrastructure that manages system-framebuffers (short: sysfb). The initial commit provides conflict-resolution for system-framebuffers. At its core it provides sysfb_evict_conflicts(), which implements conflict detection and removal for all known types of GFX driver hand-overs. So far, this includes platform-device removal, fbdev-firmware-device removal, vgacon removal and VBE detection. To further simplify the callers, it also provides helpers to figure out what hand-over to do, based on the device the new drivers binds to:

o PCI drivers can use sysfb_evict_conflicts_pci(), which will figure out the apertures automatically, and does VGA/VBE detection.

o Generic firmware drivers that might be shadowed at any address in memory can use sysfb_evict_conflicts_firmware(), basically removing *all* firmware framebuffers in effect.

This only adds the generic sysfb helpers. No users are converted, yet.

Signed-off-by: David Herrmann dh.herrmann@gmail.com

drivers/video/Kconfig | 4 + drivers/video/Makefile | 1 + drivers/video/sysfb.c | 327 +++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfb.h | 34 +++++ 4 files changed, 366 insertions(+) create mode 100644 drivers/video/sysfb.c create mode 100644 include/linux/sysfb.h

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig index 3c20af9..56a8294 100644 --- a/drivers/video/Kconfig +++ b/drivers/video/Kconfig @@ -36,6 +36,10 @@ config VIDEOMODE_HELPERS config HDMI bool +config SYSFB

•   bool
  

•   select DUMMY_CONSOLE if VT
  

• if VT source "drivers/video/console/Kconfig" endif

diff --git a/drivers/video/Makefile b/drivers/video/Makefile index 9ad3c17..df7bd75 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_VGASTATE) += vgastate.o obj-$(CONFIG_HDMI) += hdmi.o +obj-$(CONFIG_SYSFB) += sysfb.o obj-$(CONFIG_VT) += console/ obj-$(CONFIG_LOGO) += logo/ diff --git a/drivers/video/sysfb.c b/drivers/video/sysfb.c new file mode 100644 index 0000000..00585c9 --- /dev/null +++ b/drivers/video/sysfb.c @@ -0,0 +1,327 @@ +/*

• • Copyright (C) 2013-2016 Red Hat, Inc.
• • This program is free software; you can redistribute it and/or modify

it

• • under the terms of the GNU Lesser General Public License as published

by the

• • Free Software Foundation; either version 2.1 of the License, or (at

your

• • option) any later version.
• */

+#define pr_fmt(fmt) "sysfb: " fmt +#include <linux/console.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/fb.h> +#include <linux/ioport.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/pci.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/sysfb.h> +#include <linux/vt.h>

+static bool sysfb_evict_match_resource(struct sysfb_evict_ctx *ctx,

•                                  struct resource *mem)
  

+{

•   struct aperture *g;
  

•   unsigned int i;
  

•   for (i = 0; i < ctx->ap->count; ++i) {
  

•           g = &ctx->ap->ranges[i];
  

•           if (mem->start == g->base)
  

•                   return true;
  

•           if (mem->start >= g->base && mem->end < g->base + g->size)
  

•                   return true;
  

•           if ((ctx->flags & SYSFB_EVICT_VBE) && mem->start ==
  

0xA0000)

•                   return true;
  

•   }
  

•   return false;
  

+}

+static int sysfb_evict_platform_device(struct device *dev, void *userdata) +{

•   struct sysfb_evict_ctx *ctx = userdata;
  

•   struct platform_device *pdev = to_platform_device(dev);
  

•   struct resource *mem;
  

•   if (!pdev->name)
  

•           return 0;
  

•   if (!strcmp(pdev->name, "simple-framebuffer")) {
  

This doesn't work in my case where the device comes from DT and the name also contains the address: pdev->name=1e887000.framebuffer

This is one way of solving it:

   if (!pdev->dev.driver || !pdev->dev.driver->name)
            return 0;

   if (!strcmp(pdev->dev.driver->name, "simple-framebuffer")) {

Thanks for the hint, but this would skip devices that are not bound. How about the attached hunk?

Thanks David

diff --git a/drivers/video/sysfb.c b/drivers/video/sysfb.c index 0f039c6..a4ace3f 100644 --- a/drivers/video/sysfb.c +++ b/drivers/video/sysfb.c @@ -50,10 +50,8 @@ static int sysfb_evict_platform_device struct platform_device *pdev = to_platform_device(dev); struct resource *mem;

- if (!pdev->name) - return 0; - - if (!strcmp(pdev->name, "simple-framebuffer")) { + if ((pdev->name && !strcmp(pdev->name, "simple-framebuffer")) || + of_device_is_compatible(pdev->dev.of_node, "simple-framebuffer")) { mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!mem) return 0;