From f146c7bc85a51f95c05e0f8173d484eb301ece78 Mon Sep 17 00:00:00 2001 From: Danilo Krummrich Date: Thu, 13 Aug 2026 18:52:04 +0200 Subject: PCI: Add pci_irq_type() to query the allocated interrupt type Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX based on the interrupt type the PCI core selected after pci_alloc_irq_vectors(). Several drivers already open-code this check against pdev->msix_enabled and pdev->msi_enabled, or even open code this helper [1]. A common helper avoids the duplication and keeps drivers from accessing the bitfield directly (see also [2]). Acked-by: Bjorn Helgaas Tested-by: John Hubbard Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1] Inspired-by: John Hubbard Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2] Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org [ Add missing pci_irq_type() stub for CONFIG_PCI=n. ] Signed-off-by: Danilo Krummrich --- drivers/acpi/reboot.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 drivers/acpi/reboot.c (limited to 'drivers/acpi/reboot.c') diff --git a/drivers/acpi/reboot.c b/drivers/acpi/reboot.c new file mode 100644 index 000000000..b79b7c99c --- /dev/null +++ b/drivers/acpi/reboot.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define pr_fmt(fmt) "ACPI: " fmt + +#include +#include +#include +#include + +#ifdef CONFIG_PCI +static void acpi_pci_reboot(struct acpi_generic_address *rr, u8 reset_value) +{ + unsigned int devfn; + struct pci_bus *bus0; + + /* The reset register can only live on bus 0. */ + bus0 = pci_find_bus(0, 0); + if (!bus0) + return; + /* Form PCI device/function pair. */ + devfn = PCI_DEVFN((rr->address >> 32) & 0xffff, + (rr->address >> 16) & 0xffff); + pr_debug("Resetting with ACPI PCI RESET_REG.\n"); + /* Write the value that resets us. */ + pci_bus_write_config_byte(bus0, devfn, + (rr->address & 0xffff), reset_value); +} +#else +static inline void acpi_pci_reboot(struct acpi_generic_address *rr, + u8 reset_value) +{ + pr_warn_once("PCI configuration space access is not supported\n"); +} +#endif + +void acpi_reboot(void) +{ + struct acpi_generic_address *rr; + u8 reset_value; + + if (acpi_disabled) + return; + + rr = &acpi_gbl_FADT.reset_register; + + /* ACPI reset register was only introduced with v2 of the FADT */ + + if (acpi_gbl_FADT.header.revision < 2) + return; + + /* Is the reset register supported? The spec says we should be + * checking the bit width and bit offset, but Windows ignores + * these fields */ + if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER)) + return; + + reset_value = acpi_gbl_FADT.reset_value; + + /* The reset register can only exist in I/O, Memory or PCI config space + * on a device on bus 0. */ + switch (rr->space_id) { + case ACPI_ADR_SPACE_PCI_CONFIG: + acpi_pci_reboot(rr, reset_value); + break; + + case ACPI_ADR_SPACE_SYSTEM_MEMORY: + case ACPI_ADR_SPACE_SYSTEM_IO: + pr_debug("ACPI MEMORY or I/O RESET_REG.\n"); + acpi_reset(); + break; + } + + /* + * Some platforms do not shut down immediately after writing to the + * ACPI reset register, and this results in racing with the + * subsequent reboot mechanism. + * + * The 15ms delay has been found to be long enough for the system + * to reboot on the affected platforms. + */ + mdelay(15); +} -- cgit v1.3.1