8d836c66b2
PCI devices live at /sys/devices/pci0000:00/<addr> and USB devices under the xHCI controller that carries their bus, below that bus's root hub usbN; /sys/bus/pci/devices and /sys/bus/usb/devices are symlinks into it, and every device has its subsystem and driver links, which is how udev learns SUBSYSTEM and DRIVER. Writing to a device's uevent now announces it with MODALIAS, PCI_ID, PRODUCT and the rest, so udevadm trigger covers them, and the USB core sends add when a device is attached and remove as it goes. The root hub is announced when the controller comes up, before anything is plugged in. Checked under QEMU: lspci and udevadm info through the links, udevadm monitor showing the kernel and udev add event for device_add usb-kbd/usb-mouse and the remove event for device_del, and a triggered add for usb1 and 1-5. Known limits: the bus-to-controller mapping is a convention (bus N is the Nth xHCI in PCI order); PCI bridges are not parents; USB interfaces and /dev/bus/usb nodes are absent; busybox's lsusb reads /dev/bus/usb and prints nothing. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EVRhxi9zpdW2uDUN4FVcao
70 lines
3 KiB
C
70 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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// What the firmware and the buses said about this machine, kept so /sys can
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// say it again. kernel/fs/sysfs.c is the reader; each producer is named
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// beside its part.
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//
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// Read-only views, copied out under whatever lock the producer has, so a
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// caller never holds a pointer into a table that may change under it.
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// --- the memory map, as the loader handed it over (kernel/arch/x86_64/e820.c)
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struct e820_rec {
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uint64 base, len;
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uint32 type; // E820: 1 RAM, 2 reserved, 3 ACPI, 4 NVS, 5 bad
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};
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int e820_nth(int i, struct e820_rec *out); // 0, or -1 past the end
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// The RAM the page allocator was given, in bytes: MemTotal and sysinfo's
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// totalram. Not PHYSTOP, which is an address and counts the PCI hole.
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uint64 ram_total_bytes(void);
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// --- ACPI tables (kernel/arch/x86_64/acpi.c)
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//
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// Every table the RSDT or XSDT lists, then the DSDT and FACS, which only the
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// FADT points at. `sig` gets four characters, no terminator. 0 for a table,
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// 1 for an empty slot (keep counting), -1 past the end.
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int acpi_table_nth(int i, uint64 *pa, uint32 *len, char sig[4]);
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// --- SMBIOS (kernel/dev/dmi.c)
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void dmi_init(void);
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// The entry point structure and the table it describes, both physical.
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int dmi_entry(uint64 *pa, uint32 *len);
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int dmi_table(uint64 *pa, uint32 *len);
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// Bytes of physical memory, through the direct map or ioremap. 0 on failure.
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void *phys_view(uint64 pa, uint64 len);
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// The strings Linux publishes in /sys/class/dmi/id, under its names. Serial
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// numbers and the UUID are left out on purpose: nothing here needs them, and a
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// hardware report is meant to be handed to somebody else.
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enum {
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DMI_BIOS_VENDOR, DMI_BIOS_VERSION, DMI_BIOS_DATE, DMI_BIOS_RELEASE,
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DMI_SYS_VENDOR, DMI_PRODUCT_NAME, DMI_PRODUCT_VERSION, DMI_PRODUCT_SKU,
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DMI_PRODUCT_FAMILY,
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DMI_BOARD_VENDOR, DMI_BOARD_NAME, DMI_BOARD_VERSION,
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DMI_CHASSIS_VENDOR, DMI_CHASSIS_TYPE, DMI_CHASSIS_VERSION,
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DMI_NFIELDS
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};
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extern const char *const dmi_field_names[DMI_NFIELDS];
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// Length written (no terminator counted), or -1 if the machine does not say.
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int dmi_field(int f, char *out, int cap);
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// 1 if the UEFI loader booted this kernel.
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int boot_is_efi(void);
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// --- USB devices (kernel/drivers/usb/core/usb.c), one per addressed device
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struct usb_info {
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int bus, devnum, speed; // speed: USB_SPEED_*
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uint16 vid, pid, bcd;
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uint8 cls, subcls, proto; // the device descriptor's
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uint8 nconf;
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char path[24]; // Linux's name: "1-3", "2-1.4"
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char driver[16]; // the first interface's, or empty
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};
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int usb_info_nth(int i, struct usb_info *out);
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// How many USB buses have shown a device so far; bus numbers run 1..this.
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int usb_nbuses(void);
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// Tell /sys and udev a USB device appeared ("add") or is about to go ("remove").
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void sysfs_usb_uevent(const struct usb_info *u, const char *action);
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void sysfs_usb_root_uevent(int bus, const char *action);
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// A USB controller is up; number its bus and announce its root hub.
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void usb_bus_add(void *hc);
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