From 466ca2c1adbf2fc97dd559a3b69fcf0c7fe5d472 Mon Sep 17 00:00:00 2001 From: "Ronald G. Minnich" Date: Tue, 22 Oct 2019 02:02:24 +0000 Subject: Add configurable ramstage support for minimal PCI scanning This CL has changes that allow us to enable a configurable ramstage, and one change that allows us to minimize PCI scanning. Minimal scanning is a frequently requested feature. To enable it, we add two new variables to src/Kconfig CONFIGURABLE_RAMSTAGE is the overall variable controlling other options for minimizing the ramstage. MINIMAL_PCI_SCANNING is how we indicate we wish to enable minimal PCI scanning. Some devices must be scanned in all cases, such as 0:0.0. To indicate which devices we must scan, we add a new mandatory keyword to sconfig It is used in place of on, off, or hidden, and indicates a device is enabled and mandatory. Mandatory devices are always scanned. When MINIMAL_PCI_SCANNING is enabled, ONLY mandatory devices are scanned. We further add support in src/device/pci_device.c to manage both MINIMAL_PCI_SCANNING and mandatory devices. Finally, to show how this works in practice, we add mandatory keywords to 3 devices on the qemu-q35. TEST= 1. This is tested and working on the qemu-q35 target. 2. On CML-Hatch Before CL: Total Boot time: ~685ms After CL: Total Boot time: ~615ms Change-Id: I2073d9f8e9297c2b02530821ebb634ea2a5c758e Signed-off-by: Ronald G. Minnich Reviewed-on: https://review.coreboot.org/c/coreboot/+/36221 Tested-by: build bot (Jenkins) Reviewed-by: Jeremy Soller --- src/Kconfig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'src/Kconfig') diff --git a/src/Kconfig b/src/Kconfig index f538a1cc18..3742c04675 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -354,6 +354,21 @@ config RAMPAYLOAD Skip PCI enumeration logic and only allocate BAR for fixed devices (bootable devices, TPM over GSPI). +config CONFIGURABLE_RAMSTAGE + bool "Enable a configurable ramstage." + default y if ARCH_X86 + help + A configurable ramstage allows you to select which parts of the ramstage + to run. Currently, we can only select a minimal PCI scanning step. + The minimal PCI scanning will only check those parts that are enabled + in the devicetree.cb. By convention none of those devices should be bridges. + +config MINIMAL_PCI_SCANNING + bool "Enable minimal PCI scanning" + depends on CONFIGURABLE_RAMSTAGE + help + If this option is enabled, coreboot will scan only devices + marked as mandatory in devicetree.cb endmenu menu "Mainboard" -- cgit v1.2.3