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 <rminnich@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36221
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jeremy Soller <jeremy@system76.com>
diff --git a/util/sconfig/main.c b/util/sconfig/main.c
index 3b60e2a..d784642 100644
--- a/util/sconfig/main.c
+++ b/util/sconfig/main.c
@@ -516,6 +516,7 @@
new_d->enabled = status & 0x01;
new_d->hidden = (status >> 1) & 0x01;
+ new_d->mandatory = (status >> 2) & 0x01;
new_d->chip_instance = chip_instance;
chip_instance->ref_count++;
@@ -810,6 +811,7 @@
fprintf(fil, "},\n");
fprintf(fil, "\t.enabled = %d,\n", ptr->enabled);
fprintf(fil, "\t.hidden = %d,\n", ptr->hidden);
+ fprintf(fil, "\t.mandatory = %d,\n", ptr->mandatory);
fprintf(fil, "\t.on_mainboard = 1,\n");
if (ptr->subsystem_vendor > 0)
fprintf(fil, "\t.subsystem_vendor = 0x%04x,\n",