kernel/linux.git/include/linux/pci-ecam.h, branch v6.19.11

PCI: host-common: Convert to library for host controller drivers

2025-05-30T17:21:57+00:00

This common library will be used as a placeholder for helper functions shared by the host controller drivers. This avoids placing the host controller drivers specific helpers in drivers/pci/*.c, to avoid enlarging the kernel image on platforms that do not use host controller drivers at all (like x86/ACPI platforms). Suggested-by: Lukas Wunner Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250508-pcie-reset-slot-v4-3-7050093e2b50@linaro.org

PCI: host-generic: Allow {en,dis}able_device() to be provided via pci_ecam_ops

2025-01-15T20:52:12+00:00

In order to let host controller drivers using the host-generic infrastructure use the {en,dis}able_device() callbacks that can be used to configure sideband RID mapping hardware, provide these two callbacks as part of the pci_ecam_ops structure. Link: https://lore.kernel.org/r/20241204150145.800408-2-maz@kernel.org Signed-off-by: Marc Zyngier Signed-off-by: Bjorn Helgaas Reviewed-by: Frank Li Reviewed-by: Manivannan Sadhasivam

PCI: host-generic: Convert to platform remove callback returning void

2023-11-20T21:53:14+00:00

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. pci_host_common_remove() returned zero unconditionally. With that converted to return void instead, the generic pci host driver can be switched to .remove_new() trivially. Link: https://lore.kernel.org/r/20231020092107.2148311-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Bjorn Helgaas Acked-by: Will Deacon

PCI: loongson: Add ACPI init support

2022-07-14T20:25:36+00:00

Loongson PCH (LS7A chipset) will be used by both MIPS-based and LoongArch- based Loongson processors. MIPS-based Loongson uses FDT, while LoongArch- based Loongson uses ACPI. Add ACPI init support for the driver in pci-loongson.c because it is currently FDT-only. LoongArch is a new RISC ISA, mainline support will come soon, and documentations are here (in translation): https://github.com/loongson/LoongArch-Documentation Link: https://lore.kernel.org/r/20220714124216.1489304-4-chenhuacai@loongson.cn Signed-off-by: Huacai Chen Signed-off-by: Bjorn Helgaas

PCI: Dynamically map ECAM regions

2021-06-16T22:20:40+00:00

Attempting to boot 32-bit ARM kernels under QEMU's 3.x virt models fails when we have more than 512M of RAM in the model as we run out of vmalloc space for the PCI ECAM regions. This failure will be silent when running libvirt, as the console in that situation is a PCI device. In this configuration, the kernel maps the whole ECAM, which QEMU sets up for 256 buses, even when maybe only seven buses are in use. Each bus uses 1M of ECAM space, and ioremap() adds an additional guard page between allocations. The kernel vmap allocator will align these regions to 512K, resulting in each mapping eating 1.5M of vmalloc space. This means we need 384M of vmalloc space just to map all of these, which is very wasteful of resources. Fix this by only mapping the ECAM for buses we are going to be using. In my setups, this is around seven buses in most guests, which is 10.5M of vmalloc space - way smaller than the 384M that would otherwise be required. This also means that the kernel can boot without forcing extra RAM into highmem with the vmalloc= argument, or decreasing the virtual RAM available to the guest. Suggested-by: Arnd Bergmann Link: https://lore.kernel.org/r/E1lhCAV-0002yb-50@rmk-PC.armlinux.org.uk Signed-off-by: Russell King Signed-off-by: Bjorn Helgaas Reviewed-by: Arnd Bergmann

PCI: tegra: Add Tegra194 MCFG quirks for ECAM errata

2021-04-16T16:34:17+00:00

The PCIe controller in Tegra194 SoC is not ECAM-compliant. With the current hardware design, ECAM can be enabled only for one controller (the C5 controller) with bus numbers starting from 160 instead of 0. A different approach is taken to avoid this abnormal way of enabling ECAM for just one controller but to enable configuration space access for all the other controllers. In this approach, ops are added through MCFG quirk mechanism which access the configuration spaces by dynamically programming iATU (internal AddressTranslation Unit) to generate respective configuration accesses just like the way it is done in DesignWare core sub-system. This issue is specific to Tegra194 and it would be fixed in the future generations of Tegra SoCs. Link: https://lore.kernel.org/r/20210416134537.19474-1-vidyas@nvidia.com Signed-off-by: Vidya Sagar Signed-off-by: Bjorn Helgaas

PCI: Unify ECAM constants in native PCI Express drivers

2020-12-10T20:55:49+00:00

Add ECAM-related constants to provide a set of standard constants defining memory address shift values to the byte-level address that can be used to access the PCI Express Configuration Space, and then move native PCI Express controller drivers to use the newly introduced definitions retiring driver-specific ones. Refactor pci_ecam_map_bus() function to use newly added constants so that limits to the bus, device function and offset (now limited to 4K as per the specification) are in place to prevent the defective or malicious caller from supplying incorrect configuration offset and thus targeting the wrong device when accessing extended configuration space. This refactor also allows for the ".bus_shift" initialisers to be dropped when the user is not using a custom value as a default value will be used as per the PCI Express Specification. Thanks to Qian Cai , Michael Walle , and Vladimir Oltean for reporting a pci_ecam_create() issue with .bus_shift and to Vladimir for proposing the fix. [bhelgaas: incorporate Vladimir's fix, update commit log] Suggested-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20201129230743.3006978-2-kw@linux.com Tested-by: Michael Walle Signed-off-by: Krzysztof Wilczyński Signed-off-by: Lorenzo Pieralisi Signed-off-by: Bjorn Helgaas Reviewed-by: Jon Derrick Reviewed-by: Bjorn Helgaas

PCI/ACPI: Add Ampere Altra SOC MCFG quirk

2020-09-17T17:27:43+00:00

Ampere Altra SOC supports only 32-bit ECAM reads. Add an MCFG quirk for the platform. Link: https://lore.kernel.org/r/1596751055-12316-1-git-send-email-tuanphan@os.amperecomputing.com Signed-off-by: Tuan Phan Signed-off-by: Bjorn Helgaas

PCI: host-generic: Eliminate pci_host_common_probe wrappers

2020-05-07T08:29:43+00:00

Most ECAM host drivers are just different pci_ecam_ops which can be DT match table data. That's already the case in some cases, but let's do that for all the ECAM drivers. Then we can use of_device_get_match_data() in pci_host_common_probe() and eliminate the probe wrapper functions and use pci_host_common_probe() directly for probe. Link: https://lore.kernel.org/r/20200409234923.21598-4-robh@kernel.org Signed-off-by: Rob Herring Signed-off-by: Lorenzo Pieralisi Acked-by: Bjorn Helgaas Cc: Zhou Wang Cc: Lorenzo Pieralisi Cc: Andrew Murray Cc: Bjorn Helgaas Cc: Will Deacon Cc: Robert Richter Cc: Marc Gonzalez Cc: Mans Rullgard Cc: linux-pci@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org

PCI: host-generic: Support building as modules

2020-05-01T15:29:27+00:00

Enable building host-generic and its host-common dependency as a module. Link: https://lore.kernel.org/r/20200409234923.21598-3-robh@kernel.org Signed-off-by: Rob Herring Signed-off-by: Lorenzo Pieralisi Acked-by: Will Deacon Acked-by: Bjorn Helgaas Cc: Lorenzo Pieralisi Cc: Andrew Murray Cc: Bjorn Helgaas Cc: Will Deacon Cc: linux-pci@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org