IMX6SX SDB PCIe Fails in U-Boot

[eliasradi]

Hello,
  We've been trying to get PCIe working in u-boot on a Freescale IMX6SX SDB rev C and all we get is:

PCI: pcie phy link never came up
.....
Hit any key to stop autoboot: 0
=> pci
pci_bus_to_hose() failed

we've tested the following:
- u-boot from fsl-yocto-L4.1.15_2.0.0-ga and enabled "#define CONFIG_CMD_PCI"
- u-boot from uboot-imx_v2015.04_3.14.52_1.1.0_ga and enabled "#define CONFIG_CMD_PCI"
- even got u-boot.imx binary from someone with Freescale IMX6SX SDB revA board that has PCIe working. That same binary fails PCIe on a rev C board.

Anything changed on SPF-27962 from A to C that requires some changes in code? We even backtracked the changes in SPF-27962 to make the board like a rev A w.r.t. to PCIe changes and still "pci" fails.

Initially thought it is a hardware issue, but we've tested and gotten same failed results on another custom IMX6SX board.

Anyone with any ideas? Anyone with a rev C IMX6SC SDB PCIe working in u-boot?

Thanks

[igorpadykov · Accepted solution]

Hi eliasradi

reason may be pci 1v5 power setting, some pcie devices need this power,
one can try attached patch.

Also if pci works in linux and not in uboot, one can check IOMUXC_GPR_GPR8

settings and set the same in uboot.

Best regards
igor
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[eliasradi]

Yes, 1.5v was missing and needed for this card. In U-Boot board init we added: 

/* Enable power of VGEN2 1V5, needed for PCIe */
pmic_reg_read(pfuze, PFUZE100_VGEN2VOL, &reg);
reg &= ~LDO_VOL_MASK;
reg |= (LDOA_1_50V | (1 << LDO_EN));
pmic_reg_write(pfuze, PFUZE100_VGEN2VOL, reg);

Thanks Igor