coreboot-kgpe-d16/src/include/device/pciexp.h
Jeremy Soller cf2ac543a0 pciexp: Add support for allocating PCI express hotplug resources
This change adds support for allocating resources for PCI express hotplug
bridges when PCIEXP_HOTPLUG is selected. By default, this will add 32 PCI
subordinate numbers (buses), 256 MiB of prefetchable memory, 8 MiB of
non-prefetchable memory, and 8 KiB of I/O space to any device with the
PCI_EXP_SLTCAP_HPC bit set in the PCI_EXP_SLTCAP register, which
indicates hot-plugging capability. The resource allocation is configurable,
please see the PCIEXP_HOTPLUG_* variables in src/device/Kconfig.

In order to support the allocation of hotplugged PCI buses, a new field
is added to struct device called hotplug_buses. This is defaulted to
zero, but when set, it adds the hotplug_buses value to the subordinate
value of the PCI bridge. This allows devices to be plugged in and
unplugged after boot.

This code was tested on the System76 Darter Pro (darp6). Before this
change, there are not enough resources allocated to the Thunderbolt
PCI bridge to allow plugging in new devices after boot. This can be
worked around in the Linux kernel by passing a boot param such as:
pci=assign-busses,hpbussize=32,realloc

This change makes it possible to use Thunderbolt hotplugging without
kernel parameters, and attempts to match closely what our motherboard
manufacturer's firmware does by default.

Signed-off-by: Jeremy Soller <jeremy@system76.com>
Change-Id: I500191626584b83e6a8ae38417fd324b5e803afc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35946
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2020-02-05 09:32:30 +00:00

36 lines
1.2 KiB
C

#ifndef DEVICE_PCIEXP_H
#define DEVICE_PCIEXP_H
/* (c) 2005 Linux Networx GPL see COPYING for details */
enum aspm_type {
PCIE_ASPM_NONE = 0,
PCIE_ASPM_L0S = 1,
PCIE_ASPM_L1 = 2,
PCIE_ASPM_BOTH = 3,
};
#define ASPM_LTR_L12_THRESHOLD_VALUE_OFFSET 16
#define ASPM_LTR_L12_THRESHOLD_VALUE_MASK (0x3ff << ASPM_LTR_L12_THRESHOLD_VALUE_OFFSET)
#define ASPM_LTR_L12_THRESHOLD_SCALE_OFFSET 29
#define ASPM_LTR_L12_THRESHOLD_SCALE_MASK (0x7 << ASPM_LTR_L12_THRESHOLD_SCALE_OFFSET)
/* Latency tolerance reporting, max non-snoop latency value 3.14ms */
#define PCIE_LTR_MAX_NO_SNOOP_LATENCY_3146US 0x1003
/* Latency tolerance reporting, max snoop latency value 3.14ms */
#define PCIE_LTR_MAX_SNOOP_LATENCY_3146US 0x1003
void pciexp_scan_bus(struct bus *bus, unsigned int min_devfn,
unsigned int max_devfn);
void pciexp_scan_bridge(struct device *dev);
extern struct device_operations default_pciexp_ops_bus;
#if CONFIG(PCIEXP_HOTPLUG)
void pciexp_hotplug_scan_bridge(struct device *dev);
extern struct device_operations default_pciexp_hotplug_ops_bus;
#endif /* CONFIG(PCIEXP_HOTPLUG) */
unsigned int pciexp_find_extended_cap(struct device *dev, unsigned int cap);
#endif /* DEVICE_PCIEXP_H */