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path: root/drivers/pci/pci-bridge-emul.c
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2022-08-25PCI: pci-bridge-emul: Set position of PCI capabilities to real HW valuePali Rohár1-17/+31
mvebu and aardvark HW have PCIe capabilities on different offset in PCI config space. Extend pci-bridge-emul.c code to allow setting custom driver custom value where PCIe capabilities starts. With this change PCIe capabilities of both drivers are reported at the same location as where they are reported by U-Boot - in their real HW offset. Link: https://lore.kernel.org/r/20220824112124.21675-1-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
2022-03-22Merge branch 'remotes/lorenzo/pci/mvebu'Bjorn Helgaas1-56/+122
- Add Pali Rohár as pci-mvebu.c maintainer (Pali Rohár) - Make struct pci_bridge_emul_ops const (Pali Rohár) - Rename PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR to PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD since it doesn't apply to BARs (Pali Rohár) - Add new flag PCI_BRIDGE_EMUL_NO_IO_FORWARD for bridges that don't support IO forwarding (Pali Rohár) - Add Kconfig help text for CONFIG_PCI_MVEBU (Pali Rohár) - Remove duplicate nports assignment (Pali Rohár) - Set PCI_BRIDGE_EMUL_NO_IO_FORWARD when IO is unsupported (Pali Rohár) - Initialize vendor, device and revision of emulated bridge (Pali Rohár) - Fix Data Link Layer Link Active reporting on emulated bridge (Pali Rohár) - Rearrange tests in bridge emulation for easier maintenance (Russell King) - Add emulated bridge support for PCIe extended capabilities (Russell King) - Add emulated bridge support for bridge Subsystem Vendor ID capability (Pali Rohár) - Configure Maximum Link Width based on DT "num-lanes" property (Pali Rohár) - Emulate bridge Subsystem Vendor ID capability (Pali Rohár) - Emulate AER Capability (Pali Rohár) - Use PCI core bridge->ops and bridge->child_ops to separate config accesses to Root Port vs downstream devices (Pali Rohár) - Unmask all INTx interrupts; they're reported via a single shared GIC source (Pali Rohár) - Add INTx support (Pali Rohár) * remotes/lorenzo/pci/mvebu: PCI: mvebu: Implement support for legacy INTx interrupts PCI: mvebu: Fix macro names and comments about legacy interrupts dt-bindings: PCI: mvebu: Update information about intx interrupts PCI: mvebu: Use child_ops API PCI: mvebu: Add support for Advanced Error Reporting registers on emulated bridge PCI: mvebu: Add support for PCI Bridge Subsystem Vendor ID on emulated bridge PCI: mvebu: Correctly configure x1/x4 mode dt-bindings: PCI: mvebu: Add num-lanes property PCI: pci-bridge-emul: Add support for PCI Bridge Subsystem Vendor ID capability PCI: pci-bridge-emul: Add support for PCIe extended capabilities PCI: pci-bridge-emul: Re-arrange register tests PCI: mvebu: Fix reporting Data Link Layer Link Active on emulated bridge PCI: mvebu: Update comment for PCI_EXP_LNKCTL register on emulated bridge PCI: mvebu: Update comment for PCI_EXP_LNKCAP register on emulated bridge PCI: mvebu: Properly initialize vendor, device and revision of emulated bridge PCI: mvebu: Set PCI_BRIDGE_EMUL_NO_IO_FORWARD when IO is unsupported PCI: mvebu: Remove duplicate nports assignment PCI: mvebu: Add help string for CONFIG_PCI_MVEBU option PCI: pci-bridge-emul: Add support for new flag PCI_BRIDGE_EMUL_NO_IO_FORWARD PCI: pci-bridge-emul: Rename PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR to PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD PCI: pci-bridge-emul: Make struct pci_bridge_emul_ops as const MAINTAINERS: Add Pali Rohár as pci-mvebu.c maintainer
2022-02-22PCI: pci-bridge-emul: Add support for PCI Bridge Subsystem Vendor ID capabilityPali Rohár1-20/+49
This is read-only capability in PCI config space. Put it between base PCI capability and base PCI Express capability. Driver just have to specify subsystem_vendor_id and subsystem_id fields in emulated bridge structure and pci-bridge-emul takes care of correctly compose PCI Bridge Subsystem Vendor ID capability. Link: https://lore.kernel.org/r/20220222155030.988-4-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2022-02-22PCI: pci-bridge-emul: Add support for PCIe extended capabilitiesRussell King1-25/+52
Add support for PCIe extended capabilities, which we just redirect to the emulating driver. [pali: Fix writing new value with W1C bits] Link: https://lore.kernel.org/r/20220222155030.988-3-pali@kernel.org Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2022-02-22PCI: pci-bridge-emul: Re-arrange register testsRussell King1-30/+31
Re-arrange the tests for which sets of registers are being accessed so that it is easier to add further regions later. No functional change. [pali: Fix reading old value in pci_bridge_emul_conf_write] Link: https://lore.kernel.org/r/20220222155030.988-2-pali@kernel.org Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2022-02-17PCI: Add defines for normal and subtractive PCI bridgesPali Rohár1-3/+5
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.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2022-02-03PCI: pci-bridge-emul: Add support for new flag PCI_BRIDGE_EMUL_NO_IO_FORWARDPali Rohár1-0/+9
Like PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD, this new flag specifies that emulated PCI bridge does not support forwarding of IO requests in given range between primary and secondary buses. This flag should be used as argument for pci_bridge_emul_init() for hardware setup without IO support. Setting this flag cause that IO base and limit registers are read-only. Link: https://lore.kernel.org/r/20220104153529.31647-5-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Rob Herring <robh@kernel.org>
2022-02-03PCI: pci-bridge-emul: Rename PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR to ↵Pali Rohár1-1/+1
PCI_BRIDGE_EMUL_NO_PREFMEM_FORWARD This flag describe whether PCI bridge supports forwarding of prefetchable memory requests in given range between primary and secondary buses. It does not specify if bridge has support for prefetchable memory BAR (moreover this pci-bridge-emul.c driver does not provide support for BARs). So change name of this flag to be less misleading and add comment. Link: https://lore.kernel.org/r/20220104153529.31647-4-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Rob Herring <robh@kernel.org>
2022-01-13Merge branch 'remotes/lorenzo/pci/bridge-emul'Bjorn Helgaas1-16/+54
- Make emulated ROM BAR read-only by default (Pali Rohár) - Make some emulated legacy PCI bits read-only for PCIe devices (Pali Rohár) - Update reserved bits in emulated PCIe Capability (Pali Rohár) - Allow drivers to emulate different PCIe Capability versions (Pali Rohár) - Set emulated Capabilities List bit for all PCIe devices, since they must have at least a PCIe Capability (Pali Rohár) * remotes/lorenzo/pci/bridge-emul: PCI: pci-bridge-emul: Set PCI_STATUS_CAP_LIST for PCIe device PCI: pci-bridge-emul: Correctly set PCIe capabilities PCI: pci-bridge-emul: Fix definitions of reserved bits PCI: pci-bridge-emul: Properly mark reserved PCIe bits in PCI config space PCI: pci-bridge-emul: Make expansion ROM Base Address register read-only
2021-12-06PCI: pci-bridge-emul: Set PCI_STATUS_CAP_LIST for PCIe devicePali Rohár1-0/+1
Since all PCI Express device Functions are required to implement the PCI Express Capability structure, Capabilities List bit in PCI Status Register must be hardwired to 1b. Capabilities Pointer register (which is already set by pci-bride-emul.c driver) is valid only when Capabilities List is set to 1b. Link: https://lore.kernel.org/r/20211124155944.1290-7-pali@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org
2021-12-06PCI: pci-bridge-emul: Correctly set PCIe capabilitiesPali Rohár1-4/+1
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: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org
2021-12-06PCI: pci-bridge-emul: Fix definitions of reserved bitsPali Rohár1-11/+25
Some bits in PCI_EXP registers are reserved for non-root ports. Driver pci-bridge-emul.c implements PCIe Root Port device therefore it should not allow setting reserved bits of registers. Properly define non-reserved bits for all PCI_EXP registers. Link: https://lore.kernel.org/r/20211124155944.1290-5-pali@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org
2021-12-06PCI: pci-bridge-emul: Properly mark reserved PCIe bits in PCI config spacePali Rohár1-0/+21
Some bits in PCI config space are reserved when device is PCIe. Properly define behavior of PCI registers for PCIe emulated bridge and ensure that it would not be possible change these reserved bits. Link: https://lore.kernel.org/r/20211124155944.1290-3-pali@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org
2021-12-06PCI: pci-bridge-emul: Make expansion ROM Base Address register read-onlyPali Rohár1-1/+6
If expansion ROM is unsupported (which is the case of pci-bridge-emul.c driver) then ROM Base Address register must be implemented as read-only register that return 0 when read, same as for unused Base Address registers. Link: https://lore.kernel.org/r/20211124155944.1290-2-pali@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org
2021-12-02PCI: pci-bridge-emul: Add definitions for missing capabilities registersPali Rohár1-0/+43
pci-bridge-emul driver already allocates buffer for capabilities up to the PCI_EXP_SLTSTA2 register, but does not define bit access behavior for these registers. Add these missing definitions. Link: https://lore.kernel.org/r/20211130172913.9727-3-kabel@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2021-12-02PCI: pci-bridge-emul: Add description for class_revision fieldPali Rohár1-1/+5
The current assignment to the class_revision member class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16); can make the reader think that class is at high 16 bits of the member and revision at low 16 bits. In reality, class is at high 24 bits, but the class for PCI Bridge Normal Decode is PCI_CLASS_BRIDGE_PCI << 8. Change the assignment and add a comment to make this clearer. Link: https://lore.kernel.org/r/20211130172913.9727-2-kabel@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2021-10-29PCI: pci-bridge-emul: Fix emulation of W1C bitsMarek Behún1-0/+13
The pci_bridge_emul_conf_write() function correctly clears W1C bits in cfgspace cache, but it does not inform the underlying implementation about the clear request: the .write_op() method is given the value with these bits cleared. This is wrong if the .write_op() needs to know which bits were requested to be cleared. Fix the value to be passed into the .write_op() method to have requested W1C bits set, so that it can clear them. Both pci-bridge-emul users (mvebu and aardvark) are compatible with this change. Link: https://lore.kernel.org/r/20211028185659.20329-2-kabel@kernel.org Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org Cc: Russell King <rmk+kernel@armlinux.org.uk>
2021-02-17PCI: pci-bridge-emul: Fix array overruns, improve safetyRussell King1-3/+8
We allow up to PCI_EXP_SLTSTA2 registers to be accessed, but the pcie_cap_regs_behavior[] array only covers up to PCI_EXP_RTSTA. Expand this array to avoid walking off the end of it. Do the same for pci_regs_behavior for consistency[], and add a BUILD_BUG_ON() to also check the bridge->conf structure size. Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic") Link: https://lore.kernel.org/r/E1l6z9W-0006Re-MQ@rmk-PC.armlinux.org.uk Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Pali Rohár <pali@kernel.org>
2020-09-07PCI: pci-bridge-emul: Export API functionsPali Rohár1-0/+4
It allows kernel modules which are not compiled into kernel image to use pci-bridge-emul API functions. Link: https://lore.kernel.org/r/20200907111038.5811-4-pali@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Marek Behún <marek.behun@nic.cz>
2020-05-22PCI: pci-bridge-emul: Eliminate the 'reserved' memberJon Derrick1-17/+13
Per PCIe 5.0 r1.0, Terms and Acronyms, Page 80: Reserved register fields must be read only and must return 0 (all 0's for multi-bit fields) when read. Reserved encodings for register and packet fields must not be used. Any implementation dependence on a Reserved field value or encoding will result in an implementation that is not PCI Express-compliant. This patch ensures reads will return 0 for any bit not in the Read-Only, Read-Write, or Write-1-to-Clear bitmasks. Link: https://lore.kernel.org/r/20200511162117.6674-5-jonathan.derrick@intel.com Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Rob Herring <robh@kernel.org>
2020-05-22PCI: pci-bridge-emul: Update for PCIe 5.0 r1.0Jon Derrick1-15/+16
Add missing bits from PCIe 4.0 and updates for PCIe 5.0 r1.0. PCIe 4.0: Device Status bit 6 - W1C - Emergency Power Reduction Detected Link Control bits 15:14 - RW - DRS Signaling Control Slot Control bit 13 - RW - Auto Slow Power Limit Disable PCIe 5.0: Slot Control bit 14 - RW - In-Band PD Disable Link: https://lore.kernel.org/r/20200511162117.6674-4-jonathan.derrick@intel.com Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Rob Herring <robh@kernel.org>
2020-05-22PCI: pci-bridge-emul: Fix Root Cap/Status commentJon Derrick1-1/+5
The upper 16-bits of Root Control contain the Root Capabilities register. The code instead describes the Root Status register in the upper 16-bits, although it uses the correct bit definition for Root Capabilities, and for Root Status in the next definition. Fix this comment and add a comment describing the Root Status register. Link: https://lore.kernel.org/r/20200511162117.6674-3-jonathan.derrick@intel.com Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Rob Herring <robh@kernel.org>
2020-05-22PCI: pci-bridge-emul: Fix PCIe bit conflictsJon Derrick1-3/+3
This patch fixes two bit conflicts in the pci-bridge-emul driver: 1. Bit 3 of Device Status (19 of Device Control) is marked as both Write-1-to-Clear and Read-Only. It should be Write-1-to-Clear. The Read-Only and Reserved bitmasks are shifted by 1 bit due to this error. 2. Bit 12 of Slot Control is marked as both Read-Write and Reserved. It should be Read-Write. Link: https://lore.kernel.org/r/20200511162117.6674-2-jonathan.derrick@intel.com Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Rob Herring <robh@kernel.org>
2020-03-04PCI: pci-bridge-emul: Use new constant PCI_STATUS_ERROR_BITSHeiner Kallweit1-12/+2
Use new constant PCI_STATUS_ERROR_BITS to simplify the code. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-17PCI: pci-bridge-emul: Fix big-endian supportGrzegorz Jaszczyk1-12/+13
Perform conversion to little-endian before every write to configuration space and convert it back to CPU endianness on reads. Additionally, initialise every multiple byte field of config space with the cpu_to_le* macro, which is required since the structure describing config space of emulated bridge assumes little-endian convention. Signed-off-by: Grzegorz Jaszczyk <jaz@semihalf.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
2019-09-05PCI: Use static const struct, not const static structKrzysztof Wilczynski1-2/+2
Move the static keyword to the front of declarations of pci_regs_behavior[] and pcie_cap_regs_behavior[], which resolves compiler warnings when building with "W=1": drivers/pci/pci-bridge-emul.c:41:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration] const static struct pci_bridge_reg_behavior pci_regs_behavior[] = { ^ drivers/pci/pci-bridge-emul.c:176:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration] const static struct pci_bridge_reg_behavior pcie_cap_regs_behavior[] = { ^ Link: https://lore.kernel.org/r/20190826151436.4672-1-kw@linux.com Link: https://lore.kernel.org/r/20190828131733.5817-1-kw@linux.com Signed-off-by: Krzysztof Wilczynski <kw@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
2019-07-09PCI: Fix typos and whitespace errorsBjorn Helgaas1-1/+1
Fix typos in drivers/pci. Comment and whitespace changes only. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2019-02-22PCI: pci-bridge-emul: Extend pci_bridge_emul_init() with flagsThomas Petazzoni1-1/+7
Depending on the capabilities of the PCI controller/platform, the PCI-to-PCI bridge emulation behavior might need to be different. For example, on platforms that use the pci-mvebu code, we currently don't support prefetchable memory BARs, so the corresponding fields in the PCI-to-PCI bridge configuration space should be read-only. To implement this, extend pci_bridge_emul_init() to take a "flags" argument, with currently one flag supported: PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR that will make the prefetchable memory base and limit registers read-only. The pci-mvebu and pci-aardvark drivers are updated accordingly. Fixes: 1f08673eef123 ("PCI: mvebu: Convert to PCI emulated bridge config space") Reported-by: Luís Mendes <luis.p.mendes@gmail.com> Reported-by: Leigh Brown <leigh@solinno.co.uk> Tested-by: Leigh Brown <leigh@solinno.co.uk> Tested-by: Luis Mendes <luis.p.mendes@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org Cc: Luís Mendes <luis.p.mendes@gmail.com> Cc: Leigh Brown <leigh@solinno.co.uk>
2019-02-22PCI: pci-bridge-emul: Create per-bridge copy of register behaviorThomas Petazzoni1-27/+53
The behavior of the different registers of the PCI-to-PCI bridge is currently encoded in two global arrays, shared by all instances of PCI-to-PCI bridge emulation. However, we will need to tweak the behavior on a per-bridge basis, to accommodate for different capabilities of the platforms where this code is used. In preparation for this, create a per-bridge copy of the register behavior arrays, so that they can later be tweaked on a per-bridge basis. Fixes: 1f08673eef123 ("PCI: mvebu: Convert to PCI emulated bridge config space") Reported-by: Luís Mendes <luis.p.mendes@gmail.com> Reported-by: Leigh Brown <leigh@solinno.co.uk> Tested-by: Leigh Brown <leigh@solinno.co.uk> Tested-by: Luis Mendes <luis.p.mendes@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: stable@vger.kernel.org Cc: Luís Mendes <luis.p.mendes@gmail.com> Cc: Leigh Brown <leigh@solinno.co.uk>
2018-10-18PCI: Introduce PCI bridge emulated config space common logicThomas Petazzoni1-0/+408
Some PCI host controllers do not expose a configuration space for the root port PCI bridge. Due to this, the Marvell Armada 370/38x/XP PCI controller driver (pci-mvebu) emulates a root port PCI bridge configuration space, and uses that to (among other things) dynamically create the memory windows that correspond to the PCI MEM and I/O regions. Since we now need to add a very similar logic for the Marvell Armada 37xx PCI controller driver (pci-aardvark), instead of duplicating the code, we create in this commit a common logic called pci-bridge-emul. The idea of this logic is to emulate a root port PCI bridge configuration space by providing configuration space read/write operations, and faking behind the scenes the configuration space of a PCI bridge. A PCI host controller driver simply has to call pci_bridge_emul_conf_read() and pci_bridge_emul_conf_write() to read/write the configuration space of the bridge. By default, the PCI bridge configuration space is simply emulated by a chunk of memory, but the PCI host controller can override the behavior of the read and write operations on a per-register basis to do additional actions if needed. We take care of complying with the behavior of the PCI configuration space registers in terms of bits that are read-write, read-only, reserved and write-1-to-clear. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
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