drm: enable almost all PCIe functionality

linux_pci.c revisions 1.24 and 1.25 implemented most of the remaining
missing PCIe backends, but only enabled them for some amdgpu portions.

this enables all code marked with "XXX amdgpu pcie", "XXX radeon pcie",
and "XXX pcie speed". for most of it, simply removing #ifndefs __NetBSD__
to enable compliation was required, once the new "bus->max_bus_speed"
member was added to struct pci_bus. add an "always fails" backend for
pci_enable_atomic_ops_to_root() which seems to only be necessary
for virtual GPU functionality (and could be implemented if needed.)

tested on radeon 5450, 7750, R7 240 [radeon], and RX 550 [amdgpu], and
nvidia 750 and 1030 [nouveau].


this still does not quite work on nvidia cards. there are two problems
that remain:

- the call to set the link speed is skipped because the speed is set
to the default value of "-1". nvkm_pcie_set_link() will actually
determine the right value for this and for some cards, calling this
function if the current speed is -1 helps set the link speed. it
may be that on linux other paths we don't have enabled properly
would set this (there's one via debugfs, and a jetson specific one,
though perhaps setting either AC or DC speed values as boot options
(after hooking up these for netbsd) would currently work.

- worse, cards newer than kepler - geforce 900, 1000, and newer, are
all lacking the backing support to set pcie link speed. the GT 1030
card i have been testing with remains at pcie 1.0.

add pcie capability and read request size linux compat, some pci root support

implement support for:
- pcie_capability_read_dword()
- pcie_capability_read_word()
- pcie_capability_write_dword()
- pcie_capability_write_word()
- pcie_get_readrq()
- pcie_set_readrq()

implement the "struct pci_dev" bus->self member by creating a minimal fake
"struct pci_dev" for the pci bus itself. this is kind of gross. it checks
that the current device's parent is a netbsd "pci" device, and that it has
a (grand) parent "ppb" device, and then fills in the fake device based upon
the pci and ppb devices.

add some PCIE_LCSR2_TGT_LSPEED encodings, and map them to linux names.
map several other PCIE_LCSR and PCIE_LCAP names.

uncomment several pcie code segments in radeon and amdgpu. (not sure that
we can test the amdgpu_si.c change, as we use the radeon version and the
amdgpu version hangs on the one machine i have.)

tested on amdgpu (RX550) and radeon (7750 & 3650).


ok @riastradh

First whack at amdgpu. Long way to go.

Merge linux-drm-v5-6-rc3

branches: 1.3.2; 1.3.6;
Make amdgpu cik build.

- Sprinkle __UNCONST and __UNVOLATILE judiciously.
- Ifdef out debugfs stuff and other unused things.
- Add includes.
- Convert void * to char * before arithmetic.
- Add prototype for amdgpu_cik_gpu_check_soft_reset.
. XXX Should really be in a header file, but whatever...
- Mark unused variables.
- sprintf -> snprintf

Disable PCIe stuff until I can figure out what it does.

branches: 1.1.1;
New option AMDGPU_CIK for devices covered by radeon and amdgpu.

add pcie capability and read request size linux compat, some pci root support

implement support for:
- pcie_capability_read_dword()
- pcie_capability_read_word()
- pcie_capability_write_dword()
- pcie_capability_write_word()
- pcie_get_readrq()
- pcie_set_readrq()

implement the "struct pci_dev" bus->self member by creating a minimal fake
"struct pci_dev" for the pci bus itself. this is kind of gross. it checks
that the current device's parent is a netbsd "pci" device, and that it has
a (grand) parent "ppb" device, and then fills in the fake device based upon
the pci and ppb devices.

add some PCIE_LCSR2_TGT_LSPEED encodings, and map them to linux names.
map several other PCIE_LCSR and PCIE_LCAP names.

uncomment several pcie code segments in radeon and amdgpu. (not sure that
we can test the amdgpu_si.c change, as we use the radeon version and the
amdgpu version hangs on the one machine i have.)

tested on amdgpu (RX550) and radeon (7750 & 3650).


ok @riastradh

First whack at amdgpu. Long way to go.

Merge linux-drm-v5-6-rc3

branches: 1.3.2; 1.3.6;
Make amdgpu cik build.

- Sprinkle __UNCONST and __UNVOLATILE judiciously.
- Ifdef out debugfs stuff and other unused things.
- Add includes.
- Convert void * to char * before arithmetic.
- Add prototype for amdgpu_cik_gpu_check_soft_reset.
. XXX Should really be in a header file, but whatever...
- Mark unused variables.
- sprintf -> snprintf

Disable PCIe stuff until I can figure out what it does.

branches: 1.1.1;
New option AMDGPU_CIK for devices covered by radeon and amdgpu.

First whack at amdgpu. Long way to go.

Merge linux-drm-v5-6-rc3

branches: 1.3.2; 1.3.6;
Make amdgpu cik build.

- Sprinkle __UNCONST and __UNVOLATILE judiciously.
- Ifdef out debugfs stuff and other unused things.
- Add includes.
- Convert void * to char * before arithmetic.
- Add prototype for amdgpu_cik_gpu_check_soft_reset.
. XXX Should really be in a header file, but whatever...
- Mark unused variables.
- sprintf -> snprintf

Disable PCIe stuff until I can figure out what it does.

branches: 1.1.1;
New option AMDGPU_CIK for devices covered by radeon and amdgpu.

branches: 1.3.2;
Make amdgpu cik build.

- Sprinkle __UNCONST and __UNVOLATILE judiciously.
- Ifdef out debugfs stuff and other unused things.
- Add includes.
- Convert void * to char * before arithmetic.
- Add prototype for amdgpu_cik_gpu_check_soft_reset.
. XXX Should really be in a header file, but whatever...
- Mark unused variables.
- sprintf -> snprintf

Disable PCIe stuff until I can figure out what it does.

New option AMDGPU_CIK for devices covered by radeon and amdgpu.