This page does a simplified representation of the RTL9300 'longan' initialization flow when calling 'rtk_network_on'.
The output in U-boot looks like the following snippet, and translates nicely to the graph.
Enable network
RTCORE Driver Module Initialize
IOAL init
Hardware-profile probe (Forced profile: RTL9302B_8218D_2x8226_2xGE)
(RTL9302B_8218D_2x8226_2xGE)
Hardware-profile init
GPIO probe (unit 0): (found)
GPIO Init
Reset PHY gpio OK!
SPI init (unit 0) (type3)
SPI Master init
I2C probe (unit 0)
I2C init (unit 0)
NIC probe (unit 0)
Loader RTNIC Driver Module Initialize
IOAL init
RTK Driver Module Initialize
MAC probe (unit 0)
Chip 9302 (found)
MAC init (unit 0)
SMI protocol probe (unit 0)
PHY probe (unit 0)
Chip Construct (unit 0)
Chip Construct
Disable PHY Polling
PHY Reset
MAC Construct
Turn Off Serdes
Serdes Construct
PHY Construct
Turn On Serdes
Enable PHY Polling
Misc
PHY init (unit 0)
Mgmt_dev init (unit 0)
Please wait for PHY init-time ...
Note the dal_longan functions, which is where the gross of the actual switch/serdes initialization lives. For the briefness of this high level overview, the actual network init call graph is left out. This can be added later.
rtk_network_on() (from U-Boot) uboot_func.c uboot_func.c uboot_init.c uboot_init.c rtcore_init.c rtcore_init.c rtk/init.c rtk/init.c halctrl.c halctrl.c dal_mgmt.c dal_mgmt.c mac_probe.c mac_probe.c phy_probe.c phy_probe.c dal_longan_construct.c dal_longan_construct.c dal_mgmt_initDevice dal_mgmt_initDevice uboot_sdk_init() if rtcore_init_counter == 0 rtcore_init() ioal_init() hwp_probe() hwp_init() ioal_init_unitID_change() hwp_chipInfo_update() gpio_probe() drv_gpio_init() drv_spi_init() i2c_probe() drv_i2c_init() nic_probe() uboot_rtnic_drv_init() rtcore_init_counter++ if rtk_init_counter == 0 rtk_init() hal_init() hal_init_sys() phy_identify_init() dal_mgmt_init() dal_mgmt_mapper_clear() mac_probe() hal_find_device() hal_find_driver() mac_init() fMdrv_init() -> rtl9300_init() phy_mdcProto_probe() phy_probe() _phy_probe_unit() phy_attach_hook_driver() if phyType = SerDes phy_identify_driver_find_by_phyType() phy_identify_serdesDrvCtrl_get() chip_construct() -> dal_longan_construct.c dal_longan_construct_default_init() dal_longan_construct_pollingPhy_disable() dal_longan_construct_phy_reset() dal_longan_construct_macConfig_init() dal_longan_construct_serdes_off() dal_longan_construct_serdesConfig_init() dal_longan_construct_phyConfig_init() dal_longan_construct_serdes_on() dal_longan_construct_pollingPhy_enable() dal_longan_construct_miscConfig_init() phy_init() fPhydrv_init -> phy_9300_init() dal_mgmt_initDevice() -> dal_longanMapper_init() dal_longan_init() dal_longan_l2Mapper_init() dal_longan_portMapper_init() rtk_init_counter++ return success/fail loop [for each port per switch] phy_enable_set() mdelay()