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authorRonald G. Minnich <rminnich@gmail.com>2019-10-22 02:02:24 +0000
committerron minnich <rminnich@gmail.com>2020-02-08 18:57:36 +0000
commit466ca2c1adbf2fc97dd559a3b69fcf0c7fe5d472 (patch)
tree24c665b13fe23e8e6be540ef917d1c23ad175309 /src/device
parent91dc1e74a52ec33dc7f5c33dca73f02c5fe54cf0 (diff)
downloadcoreboot-466ca2c1adbf2fc97dd559a3b69fcf0c7fe5d472.tar.xz
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>
Diffstat (limited to 'src/device')
-rw-r--r--src/device/pci_device.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/src/device/pci_device.c b/src/device/pci_device.c
index 47c0e9f2d2..b1e88a6896 100644
--- a/src/device/pci_device.c
+++ b/src/device/pci_device.c
@@ -1195,6 +1195,12 @@ void pci_scan_bus(struct bus *bus, unsigned int min_devfn,
* non-existence and single function devices.
*/
for (devfn = min_devfn; devfn <= max_devfn; devfn++) {
+ if (CONFIG(MINIMAL_PCI_SCANNING)) {
+ dev = pcidev_path_behind(bus, devfn);
+ if (!dev || !dev->mandatory)
+ continue;
+ }
+
/* First thing setup the device structure. */
dev = pci_scan_get_dev(bus, devfn);