Currently unsigned ints are used to represent instructions on powerpc.
This has worked well as instructions have always been 4 byte words.
However, ISA v3.1 introduces some changes to instructions that mean
this scheme will no longer work as well. This change is Prefixed
Instructions. A prefixed instruction is made up of a word prefix
followed by a word suffix to make an 8 byte double word instruction.
No matter the endianness of the system the prefix always comes first.
Prefixed instructions are only planned for powerpc64.
Introduce a ppc_inst type to represent both prefixed and word
instructions on powerpc64 while keeping it possible to exclusively
have word instructions on powerpc32.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Fix compile error in emulate_spe()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-12-jniethe5@gmail.com
In preparation for an instruction data type that can not be directly
used with the '==' operator use functions for checking equality.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balamuruhan S <bala24@linux.ibm.com>
Link: https://lore.kernel.org/r/20200506034050.24806-11-jniethe5@gmail.com
Use a function for byte swapping instructions in preparation of a more
complicated instruction type.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balamuruhan S <bala24@linux.ibm.com>
Link: https://lore.kernel.org/r/20200506034050.24806-10-jniethe5@gmail.com
In preparation for using a data type for instructions that can not be
directly used with the '>>' operator use a function for getting the op
code of an instruction.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-9-jniethe5@gmail.com
In preparation for introducing a more complicated instruction type to
accommodate prefixed instructions use an accessor for getting an
instruction as a u32.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-8-jniethe5@gmail.com
In preparation for instructions having a more complex data type start
using a macro, ppc_inst(), for making an instruction out of a u32. A
macro is used so that instructions can be used as initializer elements.
Currently this does nothing, but it will allow for creating a data type
that can represent prefixed instructions.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Change include guard to _ASM_POWERPC_INST_H]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-7-jniethe5@gmail.com
create_branch(), create_cond_branch() and translate_branch() return the
instruction that they create, or return 0 to signal an error. Separate
these concerns in preparation for an instruction type that is not just
an unsigned int. Fill the created instruction to a pointer passed as
the first parameter to the function and use a non-zero return value to
signify an error.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-6-jniethe5@gmail.com
A modulo operation is used for calculating the current offset from a
breakpoint within the breakpoint table. As instruction lengths are
always a power of 2, this can be replaced with a bitwise 'and'. The
current check for word alignment can be replaced with checking that the
lower 2 bits are not set.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-5-jniethe5@gmail.com
The instructions for xmon's breakpoint are stored bpt_table[] which is in
the data section. This is problematic as the data section may be marked
as no execute. Move bpt_table[] to the text section.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-4-jniethe5@gmail.com
To execute an instruction out of line after a breakpoint, the NIP is set
to the address of struct bpt::instr. Here a copy of the instruction that
was replaced with a breakpoint is kept, along with a trap so normal flow
can be resumed after XOLing. The struct bpt's are located within the
data section. This is problematic as the data section may be marked as
no execute.
Instead of each struct bpt holding the instructions to be XOL'd, make a
new array, bpt_table[], with enough space to hold instructions for the
number of supported breakpoints. A later patch will move this to the
text section.
Make struct bpt::instr a pointer to the instructions in bpt_table[]
associated with that breakpoint. This association is a simple mapping:
bpts[n] -> bpt_table[n * words per breakpoint]. Currently we only need
the copied instruction followed by a trap, so 2 words per breakpoint.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-3-jniethe5@gmail.com
For modifying instructions in xmon, patch_instruction() can serve the
same role that store_inst() is performing with the advantage of not
being specific to xmon. In some places patch_instruction() is already
being using followed by store_inst(). In these cases just remove the
store_inst(). Otherwise replace store_inst() with patch_instruction().
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20200506034050.24806-2-jniethe5@gmail.com
The ps3_mm_region_destroy() and ps3_mm_vas_destroy() routines
are called very late in the shutdown via kexec's mmu_cleanup_all
routine. By the time mmu_cleanup_all runs it is too late to use
udbg_printf, and calling it will cause PS3 systems to hang.
Remove all debugging statements from ps3_mm_region_destroy() and
ps3_mm_vas_destroy() and replace any error reporting with calls
to lv1_panic.
With this change builds with 'DEBUG' defined will not cause kexec
reboots to hang, and builds with 'DEBUG' defined or not will end
in lv1_panic if an error is encountered.
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7325c4af2b4c989c19d6a26b90b1fec9c0615ddf.1589049250.git.geoff@infradead.org
System Reset and Machine Check interrupts that are not recoverable due
to being nested or interrupting when RI=0 currently panic. This is not
necessary, and can often just kill the current context and recover.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Link: https://lore.kernel.org/r/20200508043408.886394-16-npiggin@gmail.com
Similarly to the previous patch, do not trace system reset. This code
is used when there is a crash or hang, and tracing disturbs the system
more and has been known to crash in the crash handling path.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-15-npiggin@gmail.com
Rather than notrace annotations throughout a significant part of the
machine check code across kernel/ pseries/ and powernv/ which can
easily be broken and is infrequently tested, use paca->ftrace_enabled
to blanket-disable tracing of the real-mode non-maskable handler.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-14-npiggin@gmail.com
machine_check_early() is taken as an NMI, so nmi_enter() is used
there. machine_check_exception() is no longer taken as an NMI (it's
invoked via irq_work in the case a machine check hits in kernel mode),
so remove the nmi_enter() from that case.
In NMI context, hash faults don't try to refill the hash table, which
can lead to crashes accessing non-pinned kernel pages. System reset
still has this potential problem.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Drop change in show_regs() which breaks Book3E]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200508043408.886394-12-npiggin@gmail.com
With the previous patch, machine checks can use rtas_call_unlocked()
which avoids the RTAS spinlock which would deadlock if a machine
check hits while making an RTAS call.
This also avoids the complex RTAS error logging which has more RTAS
calls and includes kmalloc (which can return memory beyond RMA, which
would also crash).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200508043408.886394-11-npiggin@gmail.com
This allows rtas_args to be put on the machine check stack, which
avoids a lot of complications with re-entrancy deadlocks.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-10-npiggin@gmail.com
PAPR does not specify that fwnmi sreset should be interlocked, and
PowerVM (and therefore now QEMU) do not require it.
These "ibm,nmi-interlock" calls are ignored by firmware, but there
is a possibility that the sreset could have interrupted a machine
check and release the machine check's interlock too early, corrupting
it if another machine check came in.
This is an extremely rare case, but it should be fixed for clarity
and reducing the code executed in the sreset path. Firmware also
does not provide error information for the sreset case to look at, so
remove that comment.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Use __be64 to silence some sparse warnings]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200508043408.886394-9-npiggin@gmail.com
Updated values of USB3 related Sierra PHY registers.
This change fixes USB3 device disconnect issue observed
while enternig U1/U2 state.
Signed-off-by: Sanket Parmar <sparmar@cadence.com>
Link: https://lore.kernel.org/r/1589804053-14302-1-git-send-email-sparmar@cadence.com
Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
The max_register property must be set in order to
show up the registers in debugfs.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Link: https://lore.kernel.org/r/20200513131254.10497-2-rogerq@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
During different reboot cycles, USB PHY PLL may not always lock
during initialization and therefore can cause USB to be not usable.
Hence do not use internal FSM programming sequence for the USB
PHY initialization.
Fixes: 4dcddbb38b ("phy: sr-usb: Add Stingray USB PHY driver")
Signed-off-by: Bharat Gooty <bharat.gooty@broadcom.com>
Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Link: https://lore.kernel.org/r/20200513173947.10919-1-rayagonda.kokatanur@broadcom.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
This patch adds support for r8a77961 (R-Car M3-W+).
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1585301636-24399-5-git-send-email-yoshihiro.shimoda.uh@renesas.com
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
This patch adds support for r8a77961 (R-Car M3-W+).
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1585301636-24399-3-git-send-email-yoshihiro.shimoda.uh@renesas.com
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
It's possible that struct qmp_phy_cfg->regs references an array that is
smaller than the possible register lookups that is going to be
performed, with the resulting out-of-bounds read resulting in undefined
behavior.
One such example is when during qcom_qmp_phy_com_init() performs a
qphy_setbits() on entry QPHY_PCS_POWER_DOWN_CONTROL (i.e. 17) with
msm8996_ufsphy_regs_layout only being 12 entries long.
Solve this by inflating all "regs_layout" arrays to ensure that any
remaining entries are zero-initialized, as expected by the code.
Fixes: e4d8b05ad5 ("phy: qcom-qmp: Use proper PWRDOWN offset for sm8150 USB")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200515013643.2081941-1-bjorn.andersson@linaro.org
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Move private definitions from header to phy-omap-usb2.c file.
Get rid of unused data structures usb_dpll_params and omap_usb_phy_type.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Link: https://lore.kernel.org/r/20200515080518.26870-2-rogerq@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
phy_ops are never modified and can therefore be made const to allow the
compiler to put it in read-only memory.
Before:
text data bss dec hex filename
7831 3144 128 11103 2b5f drivers/phy/broadcom/phy-bcm-ns2-usbdrd.o
After:
text data bss dec hex filename
7959 3016 128 11103 2b5f drivers/phy/broadcom/phy-bcm-ns2-usbdrd.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200516120441.7627-2-rikard.falkeborn@gmail.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
A number of structs were not modified and can therefore be made const
to allow the compiler to put them in read-only memory.
In order to do so, update a few functions that don't modify there input
to take pointers to const.
Before:
text data bss dec hex filename
15511 6448 64 22023 5607 drivers/phy/broadcom/phy-brcm-usb.o
After:
text data bss dec hex filename
16058 5936 64 22058 562a drivers/phy/broadcom/phy-brcm-usb.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200516120441.7627-4-rikard.falkeborn@gmail.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
phy_ops are never modified and can therefore be made const to allow the
compiler to put it in read-only memory.
Before:
text data bss dec hex filename
4310 1244 0 5554 15b2 drivers/phy/broadcom/phy-bcm-sr-usb.o
After:
text data bss dec hex filename
4438 1116 0 5554 15b2 drivers/phy/broadcom/phy-bcm-sr-usb.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200516120441.7627-3-rikard.falkeborn@gmail.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/iommu/arm-smmu-v3.c:2989:26:
warning: variable ‘smmu’ set but not used [-Wunused-but-set-variable]
struct arm_smmu_device *smmu;
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Link: https://lore.kernel.org/r/20200508014955.87630-1-chenzhou10@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
The MediaTek V1 IOMMU is arm32 whose default domain type is
IOMMU_DOMAIN_UNMANAGED. Add this to satisfy the bus_iommu_probe to
enter "probe_finalize".
The iommu framework will create a iommu domain for each a device.
But all the devices share a iommu domain here, thus we skip all the
other domains in the "attach_device" except the domain we create
internally with arm_iommu_create_mapping.
Also a minor change: in the attach_device, "data" always is not null.
Remove "if (!data) return".
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Link: https://lore.kernel.org/r/1589530123-30240-1-git-send-email-yong.wu@mediatek.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tvrtko spotted that some selftests were using 'break' not 'continue',
which will fail for discontiguous engine layouts such as on Icelake
(which may have vcs0 and vcs2).
Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200518102911.3463-1-chris@chris-wilson.co.uk
Document the possibility to reference a PHY and reset-gpios and to set
max-link-speed property.
Link: https://lore.kernel.org/r/20200430080625.26070-10-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
PCI-E capability macros are already defined in linux/pci_regs.h.
Remove their reimplementation in pcie-aardvark.
Link: https://lore.kernel.org/r/20200430080625.26070-9-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
With recent proposed changes for U-Boot it is possible that bootloader
won't initialize the PHY for this controller (currently the PHY is
initialized regardless whether PCI is used in U-Boot, but with these
proposed changes the PHY is initialized only on request).
Since the mvebu-a3700-comphy driver by Miquèl Raynal supports enabling
PCIe PHY, and since Linux' functionality should be independent on what
bootloader did, add code for enabling generic PHY if found in device OF
node.
The mvebu-a3700-comphy driver does PHY powering via SMC calls to ARM
Trusted Firmware. The corresponding code in ARM Trusted Firmware skips
one register write which U-Boot does not: step 7 ("Enable TX"), see [1].
Instead ARM Trusted Firmware expects PCIe driver to do this step,
probably because the register is in PCIe controller address space,
instead of PHY address space. We therefore add this step into the
advk_pcie_setup_hw function.
[1] https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/tree/drivers/marvell/comphy/phy-comphy-3700.c?h=v2.3-rc2#n836
Link: https://lore.kernel.org/r/20200430080625.26070-8-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquèl Raynal <miquel.raynal@bootlin.com>
This register is applicable only when the controller is configured for
Endpoint mode, which is not the case for the current version of this
driver.
Attempting to remove this code though caused some ath10k cards to stop
working, so for some unknown reason it is needed here.
This should be investigated and a comment explaining this should be put
before the code, so we add a FIXME comment for now.
Link: https://lore.kernel.org/r/20200430080625.26070-7-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Add support for issuing PERST via GPIO specified in 'reset-gpios'
property (as described in PCI device tree bindings).
Some buggy cards (e.g. Compex WLE900VX or WLE1216) are not detected
after reboot when PERST is not issued during driver initialization.
If bootloader already enabled link training then issuing PERST has no
effect for some buggy cards (e.g. Compex WLE900VX) and these cards are
not detected. We therefore clear the LINK_TRAINING_EN register before.
It was observed that Compex WLE900VX card needs to be in PERST reset
for at least 10ms if bootloader enabled link training.
Tested on Turris MOX.
Link: https://lore.kernel.org/r/20200430080625.26070-6-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Currently the aardvark driver trains link in PCIe gen2 mode. This may
cause some buggy gen1 cards (such as Compex WLE900VX) to be unstable or
even not detected. Moreover when ASPM code tries to retrain link second
time, these cards may stop responding and link goes down. If gen1 is
used this does not happen.
Unconditionally forcing gen1 is not a good solution since it may have
performance impact on gen2 cards.
To overcome this, read 'max-link-speed' property (as defined in PCI
device tree bindings) and use this as max gen mode. Then iteratively try
link training at this mode or lower until successful. After successful
link training choose final controller gen based on Negotiated Link Speed
from Link Status register, which should match card speed.
Link: https://lore.kernel.org/r/20200430080625.26070-5-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Interpret zero value of max-link-speed property as invalid,
as the device tree bindings documentation specifies.
Link: https://lore.kernel.org/r/20200430080625.26070-4-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Trying to change Link Status register does not have any effect as this
is a read-only register. Trying to overwrite bits for Negotiated Link
Width does not make sense.
In future proper change of link width can be done via Lane Count Select
bits in PCIe Control 0 register.
Trying to unconditionally enable ASPM L0s via ASPM Control bits in Link
Control register is wrong. There should be at least some detection if
endpoint supports L0s as isn't mandatory.
Moreover ASPM Control bits in Link Control register are controlled by
pcie/aspm.c code which sets it according to system ASPM settings,
immediately after aardvark driver probes. So setting these bits by
aardvark driver has no long running effect.
Remove code which touches ASPM L0s bits from this driver and let
kernel's ASPM implementation to set ASPM state properly.
Some users are reporting issues that this code is problematic for some
Intel wifi cards and removing it fixes them, see e.g.:
https://bugzilla.kernel.org/show_bug.cgi?id=196339
If problems with Intel wifi cards occur even after this commit, then
pcie/aspm.c code could be modified / hooked to not enable ASPM L0s state
for affected problematic cards.
Link: https://lore.kernel.org/r/20200430080625.26070-3-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
