From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 Sender: rjwysocki@gmail.com In-Reply-To: <1519062520-198902-8-git-send-email-john.garry@huawei.com> References: <1519062520-198902-1-git-send-email-john.garry@huawei.com> <1519062520-198902-8-git-send-email-john.garry@huawei.com> From: "Rafael J. Wysocki" Date: Mon, 19 Feb 2018 22:38:19 +0100 Message-ID: Subject: Re: [PATCH v14 7/9] ACPI / scan: do not enumerate Indirect IO host children Content-Type: text/plain; charset="UTF-8" To: John Garry Cc: Mika Westerberg , "Rafael J. Wysocki" , Lorenzo Pieralisi , "Rafael J. Wysocki" , Hanjun Guo , Rob Herring , Bjorn Helgaas , Arnd Bergmann , Mark Rutland , Olof Johansson , Dann Frazier , Andy Shevchenko , Rob Herring , Joe Perches , Benjamin Herrenschmidt , Linux PCI , Linux Kernel Mailing List , ACPI Devel Maling List , Linuxarm , Corey Minyard , "devicetree@vger.kernel.org" , linux-arch , Randy Dunlap List-ID: On Mon, Feb 19, 2018 at 6:48 PM, John Garry wrote: > Through the logical PIO framework systems which otherwise have > no IO space access to legacy ISA/LPC devices may access these > devices through so-called "indirect IO" method. In this, IO > space accesses for non-PCI hosts are redirected to a host > LLDD to manually generate the IO space (bus) accesses. Hosts > are able to register a region in logical PIO space to map to > its bus address range. > > Indirect IO child devices have an associated host-specific bus > address. Special translation is required to map between > a logical PIO address for a device and it's host bus address. > > Since in the ACPI tables the child device IO resources would > be the host-specific values, it is required the ACPI scan code > should not enumerate these devices, and that this should be > the responsibility of the host driver so that it can "fixup" > the resources so that they map to the appropriate logical PIO > addresses. > > To avoid enumerating these child devices, we check whether > the parent for a device is a member of a known list of > "indirect IO" hosts. For now, the HiSilicon LPC host > controller ID is added. > > To flag a device to not be enumerated, we reuse the existing > serial bus slave flag. > > Signed-off-by: John Garry Acked-by: Rafael J. Wysocki > --- > drivers/acpi/scan.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 8e63d93..c1a60852 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -1524,11 +1524,25 @@ static int acpi_check_serial_bus_slave(struct acpi_resource *ares, void *data) > return -1; > } > > +static bool acpi_is_indirect_io_slave(struct acpi_device *device) > +{ > + struct acpi_device *parent = device->parent; > + const struct acpi_device_id indirect_io_hosts[] = { > + {"HISI0191", 0}, > + {} > + }; > + > + return parent && !acpi_match_device_ids(parent, indirect_io_hosts); > +} > + > static bool acpi_is_serial_bus_slave(struct acpi_device *device) > { > struct list_head resource_list; > bool is_serial_bus_slave = false; > > + if (acpi_is_indirect_io_slave(device)) > + return true; > + > /* Macs use device properties in lieu of _CRS resources */ > if (x86_apple_machine && > (fwnode_property_present(&device->fwnode, "spiSclkPeriod") || > -- > 1.9.1 >