linux_dsm_epyc7002/drivers/gpu/drm/bochs/bochs_kms.c
Sam Ravnborg 2a1658bf92 drm/drm_fb_helper: fix fbdev with sparc64
Recent kernels have been reported to panic using the bochs_drm
framebuffer under qemu-system-sparc64 which was bisected to
commit 7a0483ac4f ("drm/bochs: switch to generic drm fbdev emulation").

The backtrace indicates that the shadow framebuffer copy in
drm_fb_helper_dirty_blit_real() is trying to access the real
framebuffer using a virtual address rather than use an IO access
typically implemented using a physical (ASI_PHYS) access on SPARC.

The fix is to replace the memcpy with memcpy_toio() from io.h.

memcpy_toio() uses writeb() where the original fbdev code
used sbus_memcpy_toio(). The latter uses sbus_writeb().

The difference between writeb() and sbus_memcpy_toio() is
that writeb() writes bytes in little-endian, where sbus_writeb() writes
bytes in big-endian. As endian does not matter for byte writes they are
the same. So we can safely use memcpy_toio() here.

Note that this only fixes bochs, in general fbdev helpers still have
issues with mixing up system memory and __iomem space. Fixing that will
require a lot more work.

v3:
  - Improved changelog (Daniel)
  - Added FIXME to fbdev_use_iomem (Daniel)

v2:
  - Added missing __iomem cast (kernel test robot)
  - Made changelog readable and fix typos (Mark)
  - Add flag to select iomem - and set it in the bochs driver

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200709193016.291267-1-sam@ravnborg.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200725191012.GA434957@ravnborg.org
2020-07-27 16:47:46 +02:00

167 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*/
#include <linux/moduleparam.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_probe_helper.h>
#include "bochs.h"
static int defx = 1024;
static int defy = 768;
module_param(defx, int, 0444);
module_param(defy, int, 0444);
MODULE_PARM_DESC(defx, "default x resolution");
MODULE_PARM_DESC(defy, "default y resolution");
/* ---------------------------------------------------------------------- */
static const uint32_t bochs_formats[] = {
DRM_FORMAT_XRGB8888,
DRM_FORMAT_BGRX8888,
};
static void bochs_plane_update(struct bochs_device *bochs,
struct drm_plane_state *state)
{
struct drm_gem_vram_object *gbo;
if (!state->fb || !bochs->stride)
return;
gbo = drm_gem_vram_of_gem(state->fb->obj[0]);
bochs_hw_setbase(bochs,
state->crtc_x,
state->crtc_y,
state->fb->pitches[0],
state->fb->offsets[0] + gbo->bo.offset);
bochs_hw_setformat(bochs, state->fb->format);
}
static void bochs_pipe_enable(struct drm_simple_display_pipe *pipe,
struct drm_crtc_state *crtc_state,
struct drm_plane_state *plane_state)
{
struct bochs_device *bochs = pipe->crtc.dev->dev_private;
bochs_hw_setmode(bochs, &crtc_state->mode);
bochs_plane_update(bochs, plane_state);
}
static void bochs_pipe_update(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *old_state)
{
struct bochs_device *bochs = pipe->crtc.dev->dev_private;
bochs_plane_update(bochs, pipe->plane.state);
}
static const struct drm_simple_display_pipe_funcs bochs_pipe_funcs = {
.enable = bochs_pipe_enable,
.update = bochs_pipe_update,
.prepare_fb = drm_gem_vram_simple_display_pipe_prepare_fb,
.cleanup_fb = drm_gem_vram_simple_display_pipe_cleanup_fb,
};
static int bochs_connector_get_modes(struct drm_connector *connector)
{
struct bochs_device *bochs =
container_of(connector, struct bochs_device, connector);
int count = 0;
if (bochs->edid)
count = drm_add_edid_modes(connector, bochs->edid);
if (!count) {
count = drm_add_modes_noedid(connector, 8192, 8192);
drm_set_preferred_mode(connector, defx, defy);
}
return count;
}
static const struct drm_connector_helper_funcs bochs_connector_connector_helper_funcs = {
.get_modes = bochs_connector_get_modes,
};
static const struct drm_connector_funcs bochs_connector_connector_funcs = {
.fill_modes = drm_helper_probe_single_connector_modes,
.destroy = drm_connector_cleanup,
.reset = drm_atomic_helper_connector_reset,
.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};
static void bochs_connector_init(struct drm_device *dev)
{
struct bochs_device *bochs = dev->dev_private;
struct drm_connector *connector = &bochs->connector;
drm_connector_init(dev, connector, &bochs_connector_connector_funcs,
DRM_MODE_CONNECTOR_VIRTUAL);
drm_connector_helper_add(connector,
&bochs_connector_connector_helper_funcs);
bochs_hw_load_edid(bochs);
if (bochs->edid) {
DRM_INFO("Found EDID data blob.\n");
drm_connector_attach_edid_property(connector);
drm_connector_update_edid_property(connector, bochs->edid);
}
}
static struct drm_framebuffer *
bochs_gem_fb_create(struct drm_device *dev, struct drm_file *file,
const struct drm_mode_fb_cmd2 *mode_cmd)
{
if (mode_cmd->pixel_format != DRM_FORMAT_XRGB8888 &&
mode_cmd->pixel_format != DRM_FORMAT_BGRX8888)
return ERR_PTR(-EINVAL);
return drm_gem_fb_create(dev, file, mode_cmd);
}
const struct drm_mode_config_funcs bochs_mode_funcs = {
.fb_create = bochs_gem_fb_create,
.mode_valid = drm_vram_helper_mode_valid,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit,
};
int bochs_kms_init(struct bochs_device *bochs)
{
int ret;
ret = drmm_mode_config_init(bochs->dev);
if (ret)
return ret;
bochs->dev->mode_config.max_width = 8192;
bochs->dev->mode_config.max_height = 8192;
bochs->dev->mode_config.fb_base = bochs->fb_base;
bochs->dev->mode_config.preferred_depth = 24;
bochs->dev->mode_config.prefer_shadow = 0;
bochs->dev->mode_config.prefer_shadow_fbdev = 1;
bochs->dev->mode_config.fbdev_use_iomem = true;
bochs->dev->mode_config.quirk_addfb_prefer_host_byte_order = true;
bochs->dev->mode_config.funcs = &bochs_mode_funcs;
bochs_connector_init(bochs->dev);
drm_simple_display_pipe_init(bochs->dev,
&bochs->pipe,
&bochs_pipe_funcs,
bochs_formats,
ARRAY_SIZE(bochs_formats),
NULL,
&bochs->connector);
drm_mode_config_reset(bochs->dev);
return 0;
}