[U-Boot] Driver-model - Issue with early device_probe

[Suneel Garapati]

Hi All,
 Request for help on the below issue.

 Hi Simon,
 As I suppose it is related to driver-model in u-boot.

 One of the boards at Cavium has SPI as PCI device and I am trying to
 enable CONFIG_ENV_IS_IN_SPI_FLASH for this device.

 Below is the sequence which causes crash, due to early of probing for
 all parent and children in PCI node of devicetree. As some drivers,
 like network, have to have eth_initialize called before to have global
 structures initialized.

 1. Init_sequence_r in board_r.c calls initr_env before any other
 framework init is called.
 2. initr_env checks for the device to load environment from, SPI,
 calls env_relocate_spec from env_sf.c
 3. SPI probe is triggered from env_relocate_spec, because of driver
 model framework, this internally triggers device_probe.
 4. device_probe iterates on spi parent, PCI, and its childs and calls
 probe on each of them.
 5. This early probe call may work for some frameowrks but not for all.
 6. Network drivers like thunderx_smi (pci device) probe calls
 mdio_register, internally calls miiphy_get_dev_by_name which tries to
 access list mii_devs, which is uninitialized at this moment and
 crashes.
 7. mii_devs is initialized through mii_phy_init, called from
 initr_net->eth_initialize->eth_common_init.
 8. initr_net is called much later in init_sequence_r.

 There is no CONFIG item to have control on environment storage devices
 like MMC,SPI,NOR flash device probes to be singled out in the
 initr_env initcall.

 Please suggest on how to fix it or workaround. Also, let me know if I
 am missing something obvious here.

 Thanks,
 Suneel