powerpc/powernv/sriov: perform null check on iov before dereferencing iov

Currently pointer iov is being dereferenced before the null check of iov
which can lead to null pointer dereference errors. Fix this by moving the
iov null check before the dereferencing.

Detected using cppcheck static analysis:
linux/arch/powerpc/platforms/powernv/pci-sriov.c:597:12: warning: Either
the condition '!iov' is redundant or there is possible null pointer
dereference: iov. [nullPointerRedundantCheck]
num_vfs = iov->num_vfs;
^

Fixes: 052da31d45fc ("powerpc/powernv/sriov: De-indent setup and teardown")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230608095849.1147969-1-colin.i.king@gmail.com

powerpc: Fix all occurences of "the the"

Rather than waiting for the bots to fix these one-by-one, fix all
occurences of "the the" throughout arch/powerpc.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220518142629.513007-1-mpe@ellerman.id.au

powerpc: fix typos in comments

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220430185654.5855-1-Julia.Lawall@inria.fr

PCI: Rename pcibios_add_device() to pcibios_device_add()

The general convention for pcibios_* hooks is that they're named after the
corresponding pci_* function they provide a hook for. The exception is
pcibios_add_device() which provides a hook for pci_device_add().

Rename pcibios_add_device() to pcibios_device_add() so it matches
pci_device_add().

Also, remove the export of the microblaze version. The only caller must be
compiled as a built-in so there's no reason for the export.

Link: https://lore.kernel.org/r/20210913152709.48013-1-oohall@gmail.com
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com> # s390

powerpc: Drop superfluous pci_dev_is_added() calls

On powerpc, pci_dev_is_added() is called as part of SR-IOV fixups
that are done under pcibios_add_device() which in turn is only called in
pci_device_add() whih is called when a PCI device is scanned.

pci_dev_assign_added() is called in pci_bus_add_device() which is only
called after scanning the device. Thus pci_dev_is_added() is always
false and can be dropped.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Tweak change log slightly to reflect Oliver's comments]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210910141940.2598035-2-schnelle@linux.ibm.com

powerpc/powernv/sriov: fix unsigned int win compared to less than zero

Fix coccicheck warning:

arch/powerpc/platforms/powernv/pci-sriov.c:443:7-10:
WARNING: Unsigned expression compared with zero: win < 0

arch/powerpc/platforms/powernv/pci-sriov.c:462:7-10:
WARNING: Unsigned expression compared with zero: win < 0

Fixes: 39efc03e3ee8 ("powerpc/powernv/sriov: Move M64 BAR allocation into a helper")
Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1605007170-22171-1-git-send-email-kaixuxia@tencent.com

powerpc/powernv/sriov: Fix use of uninitialised variable

Initialising the value before using it is generally regarded as a good
idea so do that.

Fixes: 4c51f3e1e870 ("powerpc/powernv/sriov: Make single PE mode a per-BAR setting")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200803075408.132601-1-oohall@gmail.com

powerpc/powernv/sriov: Remove unused but set variable 'phb'

Gcc report warning as follows:

arch/powerpc/platforms/powernv/pci-sriov.c:602:25: warning:
variable 'phb' set but not used [-Wunused-but-set-variable]
602 | struct pnv_phb *phb;
| ^~~

This variable is not used, so this commit removing it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200727171112.2781-1-weiyongjun1@huawei.com

powerpc/powernv/sriov: Remove vfs_expanded

Previously iov->vfs_expanded was used for two purposes.

1) To work out how much we need to multiple the per-VF BAR size to figure
out the total space required for the IOV BAR.

2) To indicate that IOV is not usable with this device (vfs_expanded == 0).

We don't really need the field for either since the multiple in 1) is
always the number PEs supported by the PHB. Similarly, we don't really need
it in 2) either since the IOV data field will be NULL if we can't use IOV
with the device.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-16-oohall@gmail.com

powerpc/powernv/sriov: Make single PE mode a per-BAR setting

Using single PE BARs to map an SR-IOV BAR is really a choice about what
strategy to use when mapping a BAR. It doesn't make much sense for this to
be a global setting since a device might have one large BAR which needs to
be mapped with single PE windows and another smaller BAR that can be mapped
with a regular segmented window. Make the segmented vs single decision a
per-BAR setting and clean up the logic that decides which mode to use.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-15-oohall@gmail.com

powerpc/powernv/sriov: Refactor M64 BAR setup

Split up the logic so that we have one branch that handles setting up a
segmented window and another that handles setting up single PE windows for
each VF.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-14-oohall@gmail.com

powerpc/powernv/sriov: Move M64 BAR allocation into a helper

I want to refactor the loop this code is currently inside of. Hoist it on
out.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-13-oohall@gmail.com

powerpc/powernv/sriov: De-indent setup and teardown

Remove the IODA2 PHB checks. We already assume IODA2 in several places so
there's not much point in wrapping most of the setup and teardown process
in an if block.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-12-oohall@gmail.com

powerpc/powernv/sriov: Drop iov->pe_num_map[]

Currently the iov->pe_num_map[] does one of two things depending on
whether single PE mode is being used or not. When it is, this contains an
array which maps a vf_index to the corresponding PE number. When single PE
mode is not being used this contains a scalar which is the base PE for the
set of enabled VFs (for for VFn is base + n).

The array was necessary because when calling pnv_ioda_alloc_pe() there is
no guarantee that the allocated PEs would be contigious. We can now
allocate contigious blocks of PEs so this is no longer an issue. This
allows us to drop the if (single_mode) {} .. else {} block scattered
through the SR-IOV code which is a nice clean up.

This also fixes a bug in pnv_pci_sriov_disable() which is the non-atomic
bitmap_clear() to manipulate the PE allocation map. Other users of the map
assume it will be accessed with atomic ops.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-11-oohall@gmail.com

powerpc/powernv/sriov: Factor out M64 BAR setup

The sequence required to use the single PE BAR mode is kinda janky and
requires a little explanation. The API was designed with P7-IOC style
windows where the setup process is something like:

1. Configure the window start / end address
2. Enable the window
3. Map the segments of each window to the PE

For Single PE BARs the process is:

1. Set the PE for segment zero on a disabled window
2. Set the range
3. Enable the window

Move the OPAL calls into their own helper functions where the quirks can be
contained.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-9-oohall@gmail.com

powerpc/powernv/sriov: Simplify used window tracking

No need for the multi-dimensional arrays, just use a bitmap.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-8-oohall@gmail.com

powerpc/powernv/sriov: Rename truncate_iov

This prevents SR-IOV being used by making the SR-IOV BAR resources
unallocatable. Rename it to reflect what it actually does.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-7-oohall@gmail.com

powerpc/powernv/sriov: Explain how SR-IOV works on PowerNV

SR-IOV support on PowerNV is a byzantine maze of hooks. I have no idea
how anyone is supposed to know how it works except through a lot of
stuffering. Write up some docs about the overall story to help out
the next sucker^Wperson who needs to tinker with it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-6-oohall@gmail.com

powerpc/powernv/sriov: Move SR-IOV into a separate file

pci-ioda.c is getting a bit unwieldly due to the amount of stuff jammed in
there. The SR-IOV support can be extracted easily enough and is mostly
standalone, so move it into a separate file.

This patch also moves the PowerNV SR-IOV specific fields from pci_dn and
moves them into a platform specific structure. I'm not sure how they ended
up in there in the first place, but leaking platform specifics into common
code has proven to be a terrible idea so far so lets stop doing that.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-5-oohall@gmail.com