Kernel: Add basic PCI and very basic rtl8139 support

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/pci.c b/drivers/pci.c
new file mode 100644
index 0000000..a71cc9a
--- /dev/null
+++ b/drivers/pci.c
@@ -0,0 +1,45 @@
+#include <cpu/io.h>
+#include <drivers/pci.h>
+#include <stdio.h>
+
+#define CONFIG_ADDRESS 0xCF8
+#define CONFIG_DATA 0xCFC
+
+uint32_t pci_config_read32(const struct PCI_DEVICE *device, uint8_t func,
+                           uint8_t offset) {
+  uint32_t address;
+  uint32_t lbus = (uint32_t)device->bus;
+  uint32_t lslot = (uint32_t)device->slot;
+  uint32_t lfunc = (uint32_t)func;
+
+  // Create configuration address as per Figure 1
+  address = (uint32_t)((lbus << 16) | (lslot << 11) | (lfunc << 8) |
+                       (offset & 0xFC) | ((uint32_t)0x80000000));
+
+  // Write out the address
+  outl(CONFIG_ADDRESS, address);
+  return inl(CONFIG_DATA);
+}
+
+int pci_populate_device_struct(uint16_t vendor, uint16_t device,
+                               struct PCI_DEVICE *pci_device) {
+  pci_device->vendor = vendor;
+  pci_device->device = device;
+
+  for (int bus = 0; bus < 256; bus++) {
+    for (int slot = 0; slot < 256; slot++) {
+      struct PCI_DEVICE tmp;
+      tmp.bus = bus;
+      tmp.slot = slot;
+      uint32_t device_vendor = pci_config_read32(&tmp, 0, 0);
+      if (vendor != (device_vendor & 0xFFFF))
+        continue;
+      if (device != (device_vendor >> 16))
+        continue;
+      pci_device->bus = bus;
+      pci_device->slot = slot;
+      return 1;
+    }
+  }
+  return 0;
+}