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authorLukas Wunner <lukas@wunner.de>2016-11-12 21:32:34 +0000
committerIngo Molnar <mingo@kernel.org>2016-11-13 08:23:15 +0100
commit46cd4b75cd0edee76e0096225c2d31f8d90e92a2 (patch)
tree78a5df320e6ced9a378495c7ce7ef26e8532e4b9 /include/linux/efi.h
parent568bc4e87033d232c5fd00d5b0cd22a2ccc04944 (diff)
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efi: Add device path parser
We're about to extended the efistub to retrieve device properties from EFI on Apple Macs. The properties use EFI Device Paths to indicate the device they belong to. This commit adds a parser which, given an EFI Device Path, locates the corresponding struct device and returns a reference to it. Initially only ACPI and PCI Device Path nodes are supported, these are the only types needed for Apple device properties (the corresponding macOS function AppleACPIPlatformExpert::matchEFIDevicePath() does not support any others). Further node types can be added with little to moderate effort. Apple device properties is currently the only use case of this parser, but Peter Jones intends to use it to match up devices with the ConInDev/ConOutDev/ErrOutDev variables and add sysfs attributes to these devices to say the hardware supports using them as console. Thus, make this parser a separate component which can be selected with config option EFI_DEV_PATH_PARSER. It can in principle be compiled as a module if acpi_get_first_physical_node() and acpi_bus_type are exported (and efi_get_device_by_path() itself is exported). The dependency on CONFIG_ACPI is needed for acpi_match_device_ids(). It can be removed if an empty inline stub is added for that function. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Andreas Noever <andreas.noever@gmail.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20161112213237.8804-7-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/efi.h')
-rw-r--r--include/linux/efi.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/efi.h b/include/linux/efi.h
index f5a821d9b90c..261767212c47 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1148,6 +1148,26 @@ struct efi_generic_dev_path {
u16 length;
} __attribute ((packed));
+struct efi_dev_path {
+ u8 type; /* can be replaced with unnamed */
+ u8 sub_type; /* struct efi_generic_dev_path; */
+ u16 length; /* once we've moved to -std=c11 */
+ union {
+ struct {
+ u32 hid;
+ u32 uid;
+ } acpi;
+ struct {
+ u8 fn;
+ u8 dev;
+ } pci;
+ };
+} __attribute ((packed));
+
+#if IS_ENABLED(CONFIG_EFI_DEV_PATH_PARSER)
+struct device *efi_get_device_by_path(struct efi_dev_path **node, size_t *len);
+#endif
+
static inline void memrange_efi_to_native(u64 *addr, u64 *npages)
{
*npages = PFN_UP(*addr + (*npages<<EFI_PAGE_SHIFT)) - PFN_DOWN(*addr);