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libpci: use "brute force" scan for devices #132

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merged 1 commit into from
Aug 10, 2022
Merged

libpci: use "brute force" scan for devices #132

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30 changes: 8 additions & 22 deletions libpci/src/pci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -129,29 +129,19 @@ static int libpci_add_fun(uint8_t bus, uint8_t dev, uint8_t fun)

static void lib_pci_scan_bus(int bus);

static void lib_pci_scan_fun(int bus, int dev, int fun)
{
libpci_add_fun(bus, dev, fun);
if (libpci_read_reg16(bus, dev, fun, PCI_CLASS_DEVICE) == 0x0604) {
int new_bus = libpci_read_reg8(bus, dev, fun, PCI_SECONDARY_BUS);
ZF_LOGD("%s found additional bus %d from %d %d %d\n", __FUNCTION__, new_bus, bus, dev, fun);
lib_pci_scan_bus(new_bus);
}
}

static void lib_pci_scan_dev(int bus, int dev)
{
uint16_t vendor_id = libpci_read_reg16(bus, dev, 0, PCI_VENDOR_ID);
if (vendor_id == PCI_VENDOR_ID_INVALID) {
return;
}
ZF_LOGD("%s found pci device %d %d\n", __FUNCTION__, bus, dev);
lib_pci_scan_fun(bus, dev, 0);
libpci_add_fun(bus, dev, 0);
if ((libpci_read_reg8(bus, dev, 0, PCI_HEADER_TYPE) & 0x80) != 0) {
ZF_LOGD("%s found multi function device %d %d\n", __FUNCTION__, bus, dev);
for (int function = 1; function < 8; function++) {
if (libpci_read_reg16(bus, dev, function, PCI_VENDOR_ID) != PCI_VENDOR_ID_INVALID) {
lib_pci_scan_fun(bus, dev, function);
libpci_add_fun(bus, dev, function);
}
}
}
Expand All @@ -167,17 +157,13 @@ static void lib_pci_scan_bus(int bus)
void libpci_scan(ps_io_port_ops_t port_ops)
{
global_port_ops = port_ops;

/* To handle cases where PCI or PCIe buses are not accessible via a bridge from bus 0, We
* use "brute force" scan instead of recursive scan here. Details of these methods can be
* found on https://wiki.osdev.org/PCI#.22Brute_Force.22_Scan. */
ZF_LOGD("PCI :: Scanning...\n");
if ((libpci_read_reg8(0, 0, 0, PCI_HEADER_TYPE) & 0x80) == 0) {
ZF_LOGD("Single bus detected\n");
lib_pci_scan_bus(0);
} else {
for (int function = 0; function < 8; function++) {
if (libpci_read_reg16(0, 0, function, PCI_VENDOR_ID) != PCI_VENDOR_ID_INVALID) {
ZF_LOGD("%s detected bus %d\n", __FUNCTION__, function);
lib_pci_scan_bus(function);
}
}
for (int bus = 0; bus < 256; bus++) {
lib_pci_scan_bus(bus);
}
}

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