[U-Boot] AHCI controller not found

[Ding, ChiX]

Hi there
I'm testing U-boot as Coreboot payload on Intel board. It boots into U-boot shell but fails to detect AHCI controller.
SCSI:  Error: SCSI Controller(s) 8086:19B2 8086:19C2 not found

AHCI SCSI devices are defined in coreboot.h,
#define CONFIG_SCSI_AHCI
#define CONFIG_SCSI_DEV_LIST            {PCI_VENDOR_ID_INTEL, \
                        0x19b2},              \
        {PCI_VENDOR_ID_INTEL,           \
                        0x19c2}

I debug into scsi_init(void). It goes through a loop to try to find PCI device for  the AHCI controllers defined above in coreboot.h .
I tried the new code "enable driver mode for PCI" and the old code using pci_find_device() function, but both fail to find the devices.

#ifdef CONFIG_DM_PCI
                struct udevice *dev;
                int ret;

                ret = dm_pci_find_device(scsi_device_list[i].vendor,
                                         scsi_device_list[i].device, 0, &dev);
                if (!ret) {
                        busdevfunc = dm_pci_get_bdf(dev);
                        break;
                }
#else
                busdevfunc = pci_find_device(scsi_device_list[i].vendor,
                                             scsi_device_list[i].device,
                                             0);
#endif


My device tree file below is a barebone which only defines serial port, keyboard, timer. They work fine.
I wonder that in order to find AHCI controller, shall I add some definition for PCI device into the device tree file?
What's the minimum definition shall I add?

/include/ "skeleton.dtsi"
/include/ "keyboard.dtsi"
/include/ "serial.dtsi"
/include/ "rtc.dtsi"
/include/ "tsc_timer.dtsi"

/ {
        #address-cells = <1>;
        #size-cells = <1>;
        model = "Google Alex";
        compatible = "google,alex", "intel,atom-pineview";

        config {
               silent_console = <0>;
        };

        gpio: gpio {};

        serial {
                reg = <0x1000 8>;
                clock-frequency = <115200>;
        };

        tsc-timer {
                clock-frequency = <1000000000>;
        };

        chosen {
                stdout-path = "/serial";
        };

        memory { device_type = "memory"; reg = <0 0>; };

};


Thanks a lot,
Chi
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