From bd0616e6e76d5b56414a6c77131a9bb63cf5e985 Mon Sep 17 00:00:00 2001
From: Aleksa Vuckovic <aleksa@vuckovic.cc>
Date: Mon, 6 Mar 2023 01:59:33 +0100
Subject: parsing pcie MCFG table

---
 kernel/Makefile          |  1 +
 kernel/include/mcfg.h    | 31 +++++++++++++++++++++++++++++++
 kernel/src/devices/pci.c | 40 ++++++++++++++++++++++++++++++++++++++++
 kernel/src/main.c        |  2 ++
 4 files changed, 74 insertions(+)
 create mode 100644 kernel/include/mcfg.h
 create mode 100644 kernel/src/devices/pci.c

(limited to 'kernel')

diff --git a/kernel/Makefile b/kernel/Makefile
index d1c8d32..539fa45 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -24,6 +24,7 @@ OBJS = \
 	src/cpu/tss.o \
 	src/devices/disc.o \
 	src/devices/keyboard.o \
+	src/devices/pci.o \
 	src/devices/serial.o \
 	src/devices/timer.o \
 	src/fs/ext2.o \
diff --git a/kernel/include/mcfg.h b/kernel/include/mcfg.h
new file mode 100644
index 0000000..9f062c0
--- /dev/null
+++ b/kernel/include/mcfg.h
@@ -0,0 +1,31 @@
+#ifndef MCFG_H
+#define MCFG_H
+
+#include <types.h>
+
+struct config_space_mcfgt {
+	uint64_t base_addr;
+	uint16_t pci_seg_group;
+	uint8_t start_pci_bus;
+	uint8_t end_pci_bus;
+	uint32_t reserved;
+} __attribute__((packed));
+typedef struct config_space_mcfgt config_space_mcfgt;
+
+struct MCFGT {
+	uint32_t signature;
+	uint32_t length;
+	uint8_t revision;
+	uint8_t checksum;
+	uint8_t oem_id[6];
+	uint64_t oem_table_id;
+	uint32_t oem_table_revision;
+	uint32_t creator_id;
+	uint32_t creator_revision;
+	uint64_t reserved;
+} __attribute__((packed));
+typedef struct MCFGT MCFGT;
+
+void read_mcfgt(void);
+
+#endif
diff --git a/kernel/src/devices/pci.c b/kernel/src/devices/pci.c
new file mode 100644
index 0000000..85c7b69
--- /dev/null
+++ b/kernel/src/devices/pci.c
@@ -0,0 +1,40 @@
+#include <types.h>
+#include <rsdp.h>
+#include <libk/stdio.h>
+#include <mcfg.h>
+#include <heap.h>
+#include <paging.h>
+#include <libk/string.h>
+
+void read_mcfgt()
+{
+	uint64_t *mcfgt_addr = find_sys_table_addr("MCFG");
+	uint64_t mcfgt_cfg_addr;
+	size_t len;
+	size_t i;
+
+	if (mcfgt_addr == NULL) {
+		printf("MCFG not found\n");
+		return;
+	}
+
+	mcfgt_cfg_addr = (uint64_t)((uint8_t *)mcfgt_addr + sizeof(MCFGT));
+	map_addr((uint64_t)mcfgt_addr, (uint64_t)mcfgt_addr, sizeof(MCFGT));
+	MCFGT *mcfgt = (MCFGT *)kalloc(sizeof(MCFGT));
+	memcpy(mcfgt, mcfgt_addr, sizeof(MCFGT));
+	len = (mcfgt->length - sizeof(MCFGT)) / 16;
+	kfree(mcfgt);
+
+	config_space_mcfgt *cfg_space =
+		(config_space_mcfgt *)kalloc(sizeof(config_space_mcfgt));
+	for (i = 0; i < len; i++) {
+		map_addr(mcfgt_cfg_addr, mcfgt_cfg_addr,
+			 sizeof(config_space_mcfgt));
+		memcpy(cfg_space, (uint64_t *)mcfgt_cfg_addr,
+		       sizeof(config_space_mcfgt));
+		printf("addr: 0x%x, group: %d, start: %d, stop: %d\n",
+		       cfg_space->base_addr, cfg_space->pci_seg_group,
+		       cfg_space->start_pci_bus, cfg_space->end_pci_bus);
+	}
+	kfree(cfg_space);
+}
diff --git a/kernel/src/main.c b/kernel/src/main.c
index f9d1b8f..2e142ca 100644
--- a/kernel/src/main.c
+++ b/kernel/src/main.c
@@ -25,6 +25,7 @@
 #include <pmm.h>
 #include <scheduler.h>
 #include <process.h>
+#include <mcfg.h>
 
 int kernel_main(mb2_tag_header *multiboot_bootinfo, uint32_t multiboot_magic);
 int kernel_main(mb2_tag_header *multiboot_bootinfo, uint32_t multiboot_magic)
@@ -52,6 +53,7 @@ int kernel_main(mb2_tag_header *multiboot_bootinfo, uint32_t multiboot_magic)
 	apic_remap_interrupts();
 	enable_interrupts();
 	init_userspace();
+	read_mcfgt();
 
 	init_scheduler();
 
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