Slot capabilities are currently not reported because emulated bridge does
not report the PCI_EXP_FLAGS_SLOT flag.

Set PCI_EXP_FLAGS_SLOT to let the kernel know that PCI_EXP_SLT* registers
are supported.

Move setting of PCI_EXP_SLTCTL register from "dynamic" pcie_conf_read
function to static buffer as it is only statically filled the
PCI_EXP_SLTSTA_PDS flag and dynamic read callback is not needed for this
register.

Set Presence State Bit to 1 since there is no support for unplugging the
card and there is currently no platform able to detect presence of a card -
in such a case the bit needs to be set to 1.

Finally correctly set Physical Slot Number to 1 since there is only one
port and zero value is reserved for ports within the same silicon as Root
Port which is not our case for Aardvark HW.

Link: https://lore.kernel.org/r/20220524132827.8837-3-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Aardvark controller supports Advanced Error Reporting configuration
registers.

Export these registers on the emulated root bridge via new .read_ext() and
.write_ext() methods.

Note that in the Advanced Error Reporting Capability header the offset to
the next Extended Capability header is set, but it is not documented in
Armada 3700 Functional Specification. Since this change adds support only
for Advanced Error Reporting, explicitly clear PCI_EXT_CAP_NEXT bits in AER
capability header.

Now the pcieport driver correctly detects AER support and allows PCIe AER
driver to start receiving ERR interrupts. Kernel log now says:

  pcieport 0000:00:00.0: AER: enabled with IRQ 52

Link: https://lore.kernel.org/r/20220524132827.8837-2-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This reverts commit 1571d67d.

This commit broke support for setting interrupt affinity. It looks like
that it is related to the chained IRQ handler. Revert this commit until
issue with setting interrupt affinity is fixed.

Fixes: 1571d67d ("PCI: aardvark: Rewrite IRQ code to chained IRQ handler")
Link: https://lore.kernel.org/r/20220515125815.30157-1-pali@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This reverts commit b0c6ae0f.

Armada 3720 phy driver (phy-mvebu-a3700-comphy.c) does not return
-EOPNOTSUPP from phy_power_on() callback anymore.

So remove dead code which handles -EOPNOTSUPP return value.
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Acked-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Acked-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Link: https://lore.kernel.org/r/20220203214444.1508-6-kabel@kernel.orgSigned-off-by: NVinod Koul <vkoul@kernel.org>

Add these PCI class codes to pci_ids.h:

  PCI_CLASS_BRIDGE_PCI_NORMAL
  PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE

Use these defines in all kernel code for describing PCI class codes for
normal and subtractive PCI bridges.

[bhelgaas: similar change in pci-mvebu.c]
Link: https://lore.kernel.org/r/20220214114109.26809-1-pali@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Update the comment about what happens when link goes down after we have
checked for link-up. If a PIO request is done while link-down, we have
a serious problem.

Link: https://lore.kernel.org/r/20220110015018.26359-23-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

This function is now always used in driver remove method, drop the
__maybe_unused attribute.

Link: https://lore.kernel.org/r/20220110015018.26359-22-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

By default, all Legacy INTx interrupts are masked, so there is no need to
mask this interrupt during irq_map() callback.

Link: https://lore.kernel.org/r/20220110015018.26359-21-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Callback for irq_mask_ack() is the same as for irq_mask(). As there is no
special handling for irq_ack(), there is no need to define irq_mask_ack()
too.

Link: https://lore.kernel.org/r/20220110015018.26359-20-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NMarc Zyngier <maz@kernel.org>

Emulated root bridge currently provides only one Legacy INTA interrupt
which is used for reporting PCIe PME and ERR events and handled by kernel
PCIe PME and AER drivers.

Aardvark HW reports these PME and ERR events separately, so there is no
need to mix real INTA interrupt and emulated INTA interrupt for PCIe PME
and AER drivers.

Register a new advk-RP (as in Root Port) irq chip and a new irq domain
for emulated root bridge and use this new separate irq domain for
providing INTA interrupt from emulated root bridge for PME and ERR events.

The real INTA interrupt from real devices is now separate.

A custom map_irq callback function on PCI host bridge structure is used to
allocate IRQ mapping for emulated root bridge from new irq domain. Original
callback of_irq_parse_and_map_pci() is used for all other devices as before.

Link: https://lore.kernel.org/r/20220110015018.26359-19-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Enable aardvark PME interrupt unconditionally by unmasking it and read PME
requester ID to emulated bridge config space immediately after receiving
interrupt.

PME requester ID is stored in the PCIE_MSG_LOG_REG register, which contains
the last inbound message. So when new inbound message is received by HW
(including non-PM), the content in PCIE_MSG_LOG_REG register is replaced by
a new value.

PCIe specification mandates that subsequent PMEs are kept pending until the
PME Status Register bit is cleared by software by writing a 1b.

Support for masking/unmasking PME interrupt on emulated bridge via
PCI_EXP_RTCTL_PMEIE bit is now implemented only in emulated bridge config
space, to ensure that we do not miss any aardvark PME interrupt.

Reading of PCI_EXP_RTCAP and PCI_EXP_RTSTA registers is simplified as final
value is now always stored into emulated bridge config space by the
interrupt handler, so there is no need to implement support for these
registers in read_pcie callback.

Clearing of W1C bit PCI_EXP_RTSTA_PME is now also simplified as it is done
by pci-bridge-emul.c code for emulated bridge config space. So there is no
need to implement support for clearing this bit in write_pcie callback.

Link: https://lore.kernel.org/r/20220110015018.26359-18-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Currently enabling PCI_EXP_RTSTA_PME bit in PCI_EXP_RTCTL register does
nothing. This is because PCIe PME driver expects to receive PCIe interrupt
defined in PCI_EXP_FLAGS_IRQ register, but aardvark hardware does not
trigger PCIe INTx/MSI interrupt for PME event, rather it triggers custom
aardvark interrupt which this driver is not processing yet.

Fix this issue by handling PME interrupt in advk_pcie_handle_int() and
chaining it to PCIe interrupt 0 with generic_handle_domain_irq() (since
aardvark sets PCI_EXP_FLAGS_IRQ to zero). With this change PCIe PME driver
finally starts receiving PME interrupt.

Link: https://lore.kernel.org/r/20220110015018.26359-17-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

To optimize advk_pci_bridge_emul_pcie_conf_write() code, touch
PCIE_ISR0_REG and PCIE_ISR0_MASK_REG registers only when it is really
needed, when processing PCI_EXP_RTCTL_PMEIE and PCI_EXP_RTSTA_PME bits.

Link: https://lore.kernel.org/r/20220110015018.26359-16-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

The emulated bridge returns incorrect value for PCI_EXP_RTSTA register
during readout in advk_pci_bridge_emul_pcie_conf_read() function: the
correct bit is BIT(16), but we are setting BIT(23), because the code
does
  *value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16
where
  PCIE_MSG_PM_PME_MASK
is
  BIT(7).

The code should probably have been something like
  *value = (!!(isr0 & PCIE_MSG_PM_PME_MASK)) << 16,
but we are better of using an if() and using the proper macro for this
bit.

Link: https://lore.kernel.org/r/20220110015018.26359-15-kabel@kernel.org
Fixes: 8a3ebd8d ("PCI: aardvark: Implement emulated root PCI bridge config space")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

ERR interrupt is triggered when corresponding bit is unmasked in both ISR0
and PCI_EXP_DEVCTL registers. Unmasking ERR bits in PCI_EXP_DEVCTL register
is not enough. This means that currently the ERR interrupt is never
triggered.

Unmask ERR bits in ISR0 register at driver probe time. ERR interrupt is not
triggered until ERR bits are unmasked also in PCI_EXP_DEVCTL register,
which is done by AER driver. So it is safe to unconditionally unmask all
ERR bits in aardvark probe.

Aardvark HW sets PCI_ERR_ROOT_AER_IRQ to zero and when corresponding bits
in ISR0 and PCI_EXP_DEVCTL are enabled, the HW triggers a generic interrupt
on GIC. Chain this interrupt to PCIe interrupt 0 with
generic_handle_domain_irq() to allow processing of ERR interrupts.

Link: https://lore.kernel.org/r/20220110015018.26359-14-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

According to PCI 3.0 specification, sending both MSI and MSI-X interrupts
is done by DWORD memory write operation to doorbell message address. The
write operation for MSI has zero upper 16 bits and the MSI interrupt number
in the lower 16 bits, while the write operation for MSI-X contains a 32-bit
value from MSI-X table.

Since the driver only uses interrupt numbers from range 0..31, the upper
16 bits of the DWORD memory write operation to doorbell message address
are zero even for MSI-X interrupts. Thus we can enable MSI-X interrupts.

Testing proves that kernel can correctly receive MSI-X interrupts from PCIe
cards which supports both MSI and MSI-X interrupts.

Link: https://lore.kernel.org/r/20220110015018.26359-13-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

MSI address for receiving MSI interrupts needs to be correctly set before
enabling processing of MSI interrupts.

Move code for setting PCIE_MSI_ADDR_LOW_REG and PCIE_MSI_ADDR_HIGH_REG
from advk_pcie_init_msi_irq_domain() to advk_pcie_setup_hw(), before
enabling PCIE_CORE_CTRL2_MSI_ENABLE.

After this we can remove the now unused member msi_msg, which was used
only for MSI doorbell address. MSI address can be any address which cannot
be used to DMA to. So change it to the address of the main struct advk_pcie.

Link: https://lore.kernel.org/r/20220110015018.26359-12-kabel@kernel.org
Fixes: 8c39d710 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NMarc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org # f21a8b1b ("PCI: aardvark: Move to MSI handling using generic MSI support")

We should not unmask MSIs at setup, but only when kernel asks for them
to be unmasked.

At setup, mask all MSIs, and implement IRQ chip callbacks for masking
and unmasking particular MSIs.

Link: https://lore.kernel.org/r/20220110015018.26359-11-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Refactor the masking of ISR0/1 Sources and unmasking of summary MSI interrupt
so that it corresponds to the comments:
- first mask all ISR0/1
- then unmask all MSIs
- then unmask summary MSI interrupt

Link: https://lore.kernel.org/r/20220110015018.26359-10-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Use simple
  dev_fwnode(dev)
instead of
  struct device_node *node = dev->of_node;
  of_node_to_fwnode(node)
especially since the node variable is not used elsewhere in the function.

Link: https://lore.kernel.org/r/20220110015018.26359-9-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Make Aardvark's msi_domain_info structure into a private driver structure.
Domain info is same for every potential instatination of a controller.

Link: https://lore.kernel.org/r/20220110015018.26359-8-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

In [1] it was agreed that we should use struct irq_chip as a global
static struct in the driver. Even though the structure currently
contains a dynamic member (parent_device), In [2] the plans to kill it
and make the structure completely static were set out.

Convert Aardvark's priv->msi_bottom_irq_chip and priv->msi_irq_chip to
static driver structure.

[1] https://lore.kernel.org/linux-pci/877dbcvngf.wl-maz@kernel.org/
[2] https://lore.kernel.org/linux-pci/874k6gvkhz.wl-maz@kernel.org/

Link: https://lore.kernel.org/r/20220110015018.26359-7-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

It is possible that we receive spurious INTx interrupt. Check for the
return value of generic_handle_domain_irq() when processing INTx IRQ.

Link: https://lore.kernel.org/r/20220110015018.26359-6-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Rewrite the code to use irq_set_chained_handler_and_data() handler with
chained_irq_enter() and chained_irq_exit() processing instead of using
devm_request_irq().

advk_pcie_irq_handler() reads IRQ status bits and calls other functions
based on which bits are set. These functions then read its own IRQ status
bits and calls other aardvark functions based on these bits. Finally
generic_handle_domain_irq() with translated linux IRQ numbers are called.

Link: https://lore.kernel.org/r/20220110015018.26359-5-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Aardvark hardware supports Multi-MSI and MSI_FLAG_MULTI_PCI_MSI is already
set for the MSI chip. But when allocating MSI interrupt numbers for
Multi-MSI, the numbers need to be properly aligned, otherwise endpoint
devices send MSI interrupt with incorrect numbers.

Fix this issue by using function bitmap_find_free_region() instead of
bitmap_find_next_zero_area().

To ensure that aligned MSI interrupt numbers are used by endpoint devices,
we cannot use Linux virtual irq numbers (as they are random and not
properly aligned). Instead we need to use the aligned hwirq numbers.

This change fixes receiving MSI interrupts on Armada 3720 boards and
allows using NVMe disks which use Multi-MSI feature with 3 interrupts.

Without this NVMe disks freeze booting as linux nvme-core.c is waiting
60s for an interrupt.

Link: https://lore.kernel.org/r/20220110015018.26359-4-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

In advk_pcie_handle_msi() it is expected that when bit i in the W1C
register PCIE_MSI_STATUS_REG is cleared, the PCIE_MSI_PAYLOAD_REG is
updated to contain the MSI number corresponding to index i.

Experiments show that this is not so, and instead PCIE_MSI_PAYLOAD_REG
always contains the number of the last received MSI, overall.

Do not read PCIE_MSI_PAYLOAD_REG register for determining MSI interrupt
number. Since Aardvark already forbids more than 32 interrupts and uses
own allocated hwirq numbers, the msi_idx already corresponds to the
received MSI number.

Link: https://lore.kernel.org/r/20220110015018.26359-3-kabel@kernel.org
Fixes: 8c39d710 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Header file linux/pci.h defines enum pci_interrupt_pin with corresponding
PCI_INTERRUPT_* values.

Link: https://lore.kernel.org/r/20220110015018.26359-2-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NBjorn Helgaas <bhelgaas@google.com>

It is read-only constant structure, so properly mark it with const keyword.

Link: https://lore.kernel.org/r/20220104153529.31647-3-pali@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Acked-by: NThomas Petazzoni <thomas.petazzoni@bootlin.com>

Older mvebu hardware provides PCIe Capability structure only in version 1.
New mvebu and aardvark hardware provides it in version 2. So do not force
version to 2 in pci_bridge_emul_init() and rather allow drivers to set
correct version. Drivers need to set version in pcie_conf.cap field without
overwriting PCI_CAP_LIST_ID register. Both drivers (mvebu and aardvark) do
not provide slot support yet, so do not set PCI_EXP_FLAGS_SLOT flag.

Link: https://lore.kernel.org/r/20211124155944.1290-6-pali@kernel.org
Fixes: 23a5fba4 ("PCI: Introduce PCI bridge emulated config space common logic")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org

IORESOURCE_MEM_64 is not a resource type but a type flag.

Remove incorrect check for type IORESOURCE_MEM_64.

Link: https://lore.kernel.org/r/20211125160148.26029-2-kabel@kernel.org
Fixes: 64f160e1 ("PCI: aardvark: Configure PCIe resources from 'ranges' DT property")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Disable the PCIe PHY when unbinding driver. This should save some power.

Link: https://lore.kernel.org/r/20211130172913.9727-12-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Disable link training circuit in driver unbind sequence. We want to
leave link training in the same state as it was before the driver was
probed.

Link: https://lore.kernel.org/r/20211130172913.9727-11-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Put the PCIe card into reset by asserting PERST# signal when unbinding
driver. It doesn't make sense to leave the card working if it can't
communicate with the host. This should also save some power.

Link: https://lore.kernel.org/r/20211130172913.9727-10-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Free config space for emulated root bridge when unbinding driver to fix
memory leak. Do it after disabling and masking all interrupts, since
aardvark interrupt handler accesses config space of emulated root
bridge.

Link: https://lore.kernel.org/r/20211130172913.9727-9-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Ensure that no interrupt can be triggered after driver unbind.

Link: https://lore.kernel.org/r/20211130172913.9727-8-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Ensure that after driver unbind PCIe cards are not able to forward
memory and I/O requests in the upstream direction.

Link: https://lore.kernel.org/r/20211130172913.9727-7-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add two more comments into the advk_pcie_remove() method.

Link: https://lore.kernel.org/r/20211130172913.9727-6-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

We already clear all the other interrupts (ISR0, ISR1, HOST_CTRL_INT).

Define a new macro PCIE_MSI_ALL_MASK and do the same clearing for MSIs,
to ensure that we don't start receiving spurious interrupts.

Use this new mask in advk_pcie_handle_msi();

Link: https://lore.kernel.org/r/20211130172913.9727-5-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

PCI aardvark hardware supports access to DEVCAP2, DEVCTL2, LNKCAP2 and
LNKCTL2 configuration registers of PCIe core via PCIE_CORE_PCIEXP_CAP.
Export them via emulated software root bridge.

Link: https://lore.kernel.org/r/20211130172913.9727-4-kabel@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

This reverts commit 239edf68.

239edf68 ("PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated
bridge") added support for the Type 1 Expansion ROM BAR at config offset
0x38, based on the register being listed in the Marvell Armada A3720 spec.
But the spec doesn't document it at all for RC mode, and there is no ROM in
the SOC, so remove this emulation for now.

The PCI bridge which represents aardvark's PCIe Root Port has an Expansion
ROM Base Address register at offset 0x30, but its meaning is different than
PCI's Expansion ROM BAR register, although the layout is the same.  (This
is why we thought it does the same thing.)

First: there is no ROM (or part of BootROM) in the A3720 SOC dedicated for
PCIe Root Port (or controller in RC mode) containing executable code that
would initialize the Root Port, suitable for execution in bootloader (this
is how Expansion ROM BAR is used on x86).

Second: in A3720 spec the register (address 0xD0070030) is not documented
at all for Root Complex mode, but similar to other BAR registers, it has an
"entangled partner" in register 0xD0075920, which does address translation
for the BAR in 0xD0070030:

  - the BAR register sets the address from the view of PCIe bus

  - the translation register sets the address from the view of the CPU

The other BAR registers also have this entangled partner, and they can be
used to:

  - in RC mode: address-checking on the receive side of the RC (they can
    define address ranges for memory accesses from remote Endpoints to the
    RC)

  - in Endpoint mode: allow the remote CPU to access memory on A3720

The Expansion ROM BAR has only the Endpoint part documented, but from the
similarities we think that it can also be used in RC mode in that way.

So either Expansion ROM BAR has different meaning (if the hypothesis above
is true), or we don't know it's meaning (since it is not documented for RC
mode).

Remove the register from the emulated bridge accessing functions.

[bhelgaas: summarize reason for removal (first paragraph)]
Fixes: 239edf68 ("PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated bridge")
Link: https://lore.kernel.org/r/20211125160148.26029-3-kabel@kernel.orgSigned-off-by: NMarek Behún <kabel@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NPali Rohár <pali@kernel.org>