[0/8] firmware/sysfb: Track parent device for screen_info

Message

Thomas Zimmermann Jan. 17, 2024, 12:39 p.m. UTC

Detect the firmware framebuffer's parent device from the global
screen_info state and set up the framebuffer's device accordingly.
Remove the equivalent functionality from efifb. Other drivers for
firmware framebuffers, such as simpledrm or vesafb, now add these
new features.

Patches 1 and 2 provide a set of helper functions to avoid parsing
the screen_info values manually. Decoding screen_info is fragile and
many drivers get it wrong. We should later adopt these helpers in
existing drivers, such as efifb, vesafb, as well.

Patches 3 and 4 set the firmware framebuffer's parent device. There
is code in efifb to do something similar for power management. That
is now obsolete and being cleaned up. Setting the parent device makes
Linux track the power management correctly.

Patches 5 and 6 track the parent device's enable state. We don't
create framebuffer devices if the underlying hardware device has been
disabled. Remove the functionality from efifb.

Patches 7 and 8 track the parent device's PCI BAR location. It can
happen on aarch64 that the firmware framebuffer moves its location
during the kernel's boot. We now fix up the screen_info state to
point to the correct location. Again remove such functionality from
efifb.

Thomas Zimmermann (8):
  video: Add helpers for decoding screen_info
  video: Provide screen_info_get_pci_dev() to find screen_info's PCI
    device
  firmware/sysfb: Set firmware-framebuffer parent device
  fbdev/efifb: Remove PM for parent device
  firmware/sysfb: Create firmware device only for enabled PCI devices
  fbdev/efifb: Do not track parent device status
  firmware/sysfb: Update screen_info for relocated EFI framebuffers
  fbdev/efifb: Remove framebuffer relocation tracking

 drivers/firmware/Kconfig            |   1 +
 drivers/firmware/sysfb.c            |  37 ++++++-
 drivers/firmware/sysfb_simplefb.c   |   5 +-
 drivers/video/Kconfig               |   4 +
 drivers/video/Makefile              |   4 +
 drivers/video/fbdev/efifb.c         |  97 +-----------------
 drivers/video/screen_info_generic.c | 148 ++++++++++++++++++++++++++++
 drivers/video/screen_info_pci.c     | 142 ++++++++++++++++++++++++++
 include/linux/screen_info.h         | 126 +++++++++++++++++++++++
 include/linux/sysfb.h               |   3 +-
 10 files changed, 472 insertions(+), 95 deletions(-)
 create mode 100644 drivers/video/screen_info_generic.c
 create mode 100644 drivers/video/screen_info_pci.c