From a3751212a8eeece59d2018c455000f30ed7e5bb7 Mon Sep 17 00:00:00 2001 From: Frank Li Date: Tue, 14 Jan 2025 15:37:08 -0500 Subject: PCI: Add enable_device() and disable_device() callbacks for bridges MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some PCI host bridges require special handling when enabling or disabling PCI devices. For example, the i.MX95 platform has a lookup table to map Requester IDs to StreamIDs, which the SMMU and MSI controller use to identify the source of DMA accesses. Without this mapping, DMA accesses may target unintended memory, which would corrupt memory or read the wrong data. Add a host bridge enable_device() hook the imx6 driver can use to configure the Requester ID to StreamID mapping. The hardware table isn't big enough to map all possible Requester IDs, so this hook may fail if no table space is available. In that case, return failure from pci_enable_device(). It might make more sense to make pci_set_master() decline to enable bus mastering and return failure, but it currently doesn't have a way to return failure. Link: https://lore.kernel.org/r/20250114-imx95_lut-v9-1-39f58dbed03a@nxp.com Tested-by: Marc Zyngier Signed-off-by: Frank Li Signed-off-by: Bjorn Helgaas [kwilczynski: commit log] Signed-off-by: Krzysztof Wilczyński Reviewed-by: Marc Zyngier Acked-by: Manivannan Sadhasivam --- include/linux/pci.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/pci.h') diff --git a/include/linux/pci.h b/include/linux/pci.h index db9b47ce3eef..bcbef004dd56 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -595,6 +595,8 @@ struct pci_host_bridge { u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */ int (*map_irq)(const struct pci_dev *, u8, u8); void (*release_fn)(struct pci_host_bridge *); + int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); + void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev); void *release_data; unsigned int ignore_reset_delay:1; /* For entire hierarchy */ unsigned int no_ext_tags:1; /* No Extended Tags */ -- cgit