diff --git a/tools/unit-tests/Makefile b/tools/unit-tests/Makefile
index 9d3644602..83c771be2 100644
--- a/tools/unit-tests/Makefile
+++ b/tools/unit-tests/Makefile
@@ -39,6 +39,9 @@ unit-aes256: ../../include/target.h unit-extflash.c
 unit-chacha20: ../../include/target.h unit-extflash.c
 	gcc -o $@ $^ $(CFLAGS) $(LDFLAGS)
 
+unit-pci:  unit-pci.c ../../src/pci.c
+	gcc -o $@ $< $(CFLAGS) $(LDFLAGS)
+
 %.o:%.c
 	gcc -c -o $@ $^ $(CFLAGS)
 
diff --git a/tools/unit-tests/unit-pci.c b/tools/unit-tests/unit-pci.c
new file mode 100644
index 000000000..b48065655
--- /dev/null
+++ b/tools/unit-tests/unit-pci.c
@@ -0,0 +1,178 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <check.h>
+
+#define MOCKED_BASE (2*1024*1024*1024ULL)
+#define MOCKED_LEN (1024*1024*1024ULL)
+#define PCI_USE_ECAM
+#define PCI_ECAM_BASE MOCKED_BASE
+
+#include <pci.h>
+#include <pci.c>
+
+struct  type1_pci_header {
+    uint16_t vendor_id;
+    uint16_t device_id;
+    uint16_t command;
+    uint16_t status;
+    uint8_t revision_id;
+    uint8_t prog_if;
+    uint8_t subclass;
+    uint8_t class_code;
+    uint8_t cache_line_size;
+    uint8_t latency_timer;
+    uint8_t header_type;
+    uint8_t bist;
+    uint32_t base_address_0;
+    uint32_t base_address_1;
+    uint8_t primary_bus_number;
+    uint8_t secondary_bus_number;
+    uint8_t subordinate_bus_number;
+    uint8_t secondary_latency_timer;
+    uint16_t io_base;
+    uint16_t io_limit;
+    uint16_t secondary_status;
+    uint16_t memory_base;
+    uint16_t memory_limit;
+    uint16_t prefetchable_memory_base;
+    uint16_t prefetchable_memory_limit;
+    uint32_t prefetchable_base_upper;
+    uint32_t prefetchable_limit_upper;
+    uint16_t io_base_upper;
+    uint16_t io_limit_upper;
+    uint8_t capability_pointer;
+    uint8_t reserved_0[3];
+    uint32_t expansion_rom_base_address;
+    uint8_t interrupt_line;
+    uint8_t interrupt_pin;
+    uint16_t bridge_control;
+};
+
+struct type1_pci_header type1_pci_header_mock = {
+    .vendor_id = 0xdead,
+    .device_id = 0xddee,
+    .status = 0x8000,
+    .command = 0x0010,
+    .class_code = 0x06,
+    .subclass = 0x04,
+    .prog_if = 0x80,
+    .revision_id = 0x03,
+    .bist = 0x00,
+    .header_type = 0x01,
+    .latency_timer = 0x40,
+    .cache_line_size = 0x08,
+    .base_address_0 = 0x12345678,
+    .base_address_1 = 0x9abcdef0,
+    .secondary_latency_timer = 0xee,
+    .subordinate_bus_number = 0xdd,
+    .secondary_bus_number = 0xbb,
+    .primary_bus_number = 0xaa,
+    .secondary_status = 0x0000,
+    .io_limit = 0xffff,
+    .io_base = 0x0000,
+    .memory_limit = 0xffff,
+    .memory_base = 0x0000,
+    .prefetchable_memory_limit = 0xffff,
+    .prefetchable_memory_base = 0x0000,
+    .prefetchable_base_upper = 0x00000000,
+    .prefetchable_limit_upper = 0x00000000,
+    .io_limit_upper = 0x0000,
+    .io_base_upper = 0x0000,
+    .reserved_0 = {0x00, 0x00},
+    .capability_pointer = 0x00,
+    .expansion_rom_base_address = 0x13579bdf,
+    .bridge_control = 0x0000,
+    .interrupt_pin = 0x01,
+    .interrupt_line = 0x0a
+};
+
+void mmio_write32(uintptr_t address, uint32_t value)
+{
+    uint32_t *p = (uint32_t*)address;
+    *p = value;
+}
+
+uint32_t mmio_read32(uintptr_t address)
+{
+    return *((uint32_t*)(address));
+}
+
+void panic()
+{
+    ck_abort_msg("panic!");
+}
+
+START_TEST (test_pci_config_write)
+{
+    struct type1_pci_header *hdr_mem;
+    uint16_t reg16;
+    uint8_t reg8;
+
+    hdr_mem =
+        (struct type1_pci_header *)mmap((uint8_t *)MOCKED_BASE, MOCKED_LEN,
+                                        PROT_WRITE | PROT_READ,
+                MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
+
+    ck_assert_ptr_eq(hdr_mem, (uint8_t*)MOCKED_BASE);
+
+    memcpy(hdr_mem, &type1_pci_header_mock, sizeof(type1_pci_header_mock));
+    reg16 = pci_config_read16(0, 0, 0, PCI_VENDOR_ID_OFFSET);
+    ck_assert_uint_eq(reg16, hdr_mem->vendor_id);
+    reg16 = pci_config_read16(0, 0, 0, PCI_DEVICE_ID_OFFSET);
+    ck_assert_uint_eq(reg16, hdr_mem->device_id);
+    reg16 = 0xdead;
+    pci_config_write16(0, 0, 0, PCI_VENDOR_ID_OFFSET, reg16);
+    ck_assert_uint_eq(reg16, hdr_mem->vendor_id);
+    reg16 = 0xbeef;
+    pci_config_write16(0, 0, 0, PCI_DEVICE_ID_OFFSET, reg16);
+    ck_assert_uint_eq(reg16, hdr_mem->device_id);
+    reg8 = pci_config_read8(0, 0, 0, PCI_PRIMARY_BUS);
+    ck_assert_uint_eq(reg8, hdr_mem->primary_bus_number);
+    reg8 = pci_config_read8(0, 0, 0, PCI_SECONDARY_BUS);
+    ck_assert_uint_eq(reg8, hdr_mem->secondary_bus_number);
+    reg8 = 0xbe;
+    pci_config_write8(0, 0, 0, PCI_PRIMARY_BUS, reg8);
+    ck_assert_uint_eq(reg8, hdr_mem->primary_bus_number);
+    reg8 = 0xca;
+    pci_config_write8(0, 0, 0, PCI_SECONDARY_BUS, reg8);
+    ck_assert_uint_eq(reg8, hdr_mem->secondary_bus_number);
+    pci_config_write32(0, 0, 0, PCI_PRIMARY_BUS, 0xaabbccdd);
+    ck_assert_uint_eq(0xaabbccdd, *((uint32_t*)&(hdr_mem->primary_bus_number)));
+    reg8 = pci_config_read8(0, 0, 0, PCI_SECONDARY_BUS);
+    ck_assert_uint_eq(reg8, hdr_mem->secondary_bus_number);
+    reg8 = 0xbe;
+    pci_config_write8(0, 0, 0, PCI_PRIMARY_BUS, reg8);
+    ck_assert_uint_eq(reg8, hdr_mem->primary_bus_number);
+
+    munmap(hdr_mem, MOCKED_LEN);
+}
+END_TEST
+
+Suite *wolfboot_suite(void)
+{
+
+    /* Suite initialization */
+    Suite *s = suite_create("wolfboot-pci");
+
+    /* Test cases */
+    TCase *pci_config  = tcase_create("pci-config-write");
+
+    tcase_add_test(pci_config, test_pci_config_write);
+    tcase_set_timeout(pci_config, 60*5);
+    suite_add_tcase(s, pci_config);
+
+    return s;
+}
+
+int main(void)
+{
+    int fails;
+    Suite *s = wolfboot_suite();
+    SRunner *sr = srunner_create(s);
+    srunner_run_all(sr, CK_NORMAL);
+    fails = srunner_ntests_failed(sr);
+    srunner_free(sr);
+    return fails;
+}