Has anyone attempted to add i.MX6 PCIe support to U-Boot?

kitz36 · ‎10-25-2012

We're working on a custom board that uses the i.MX6 to interface to a single endpoint via PCIe. The link will mostly be used in Linux, but I would like to bring the link up and play with the endpoint from U-Boot in board bring-up. I don't see any i.MX6 PCIe support in the ARM2 or SabreLite U-boot trees. Has anyone tried to get this going in U-Boot?

YixingKong · ‎02-16-2014

Charles

It seem your issue had been resolved. If you are fine I will close the discussion in 3 days.

Thanks,

Yixing

OtavioSalvador · ‎01-23-2014

You can use the 2014.01 U-Boot version which includes MarekVasut patches for PCIe.

MarekVasut · ‎01-24-2014

You're wrong, they're scheduled for 2014.04 . See git.denx.de Git - u-boot/u-boot-imx.git/shortlog .

I tested this with XHCI PCIe card, Intel 82574L NIC , Intel i210 NIC , PCIe SATA controller and a few others.

MarekVasut · ‎01-24-2014

Even better, here's a bundle with V2 of the patches which contain LTSSM fixes U-Boot - Patchwork . Stefano will push them into u-boot-imx/master this weekend I heard ...

MarekVasut · ‎01-24-2014

You will also want [U-Boot] pci: mx6: Implement reset callback - Patchwork and you _WILL_ want to reimplement the imx6_pcie_toggle_reset() with proper GPIO reset for the PCIe, otherwise you _WILL_ have issues with the bus not coming up.

wallyyeh · ‎01-24-2014

after talk to Marek, I compare patches v1 and v2.

and find out v2 patch will check return of imx_pcie_link_up() before doing pci_hose_scan().

I guess that fix empty device on bridge issue.

and I so excited that I accidentally break my DC adapter... so I have to wait for tomorrow morning to get new one.

orz...

MarekVasut · ‎01-24-2014

Yes, if the device is not populated, you must not touch the IO space, otherwise the entire CPU will freeze. Even worse, you won't be able to break the CPU with a debugger. The V2 of the patches do fix it. It also fixes the problem where the link was considered ready too early.

And like I said, you _MUST_ implement the reset callback, like so:

gpio_set_value(..., 1);

mdelay(100);

gpio_set_value(..., 0);

mdelay(100);

These mdelay() calls might be shorter, I didn't research how short the delay should be here. 100mS is a safe value.

rajniks · ‎10-27-2014

Hi Marek,

I am working with LTIB from Freescale and it supports u-boot-2009-08. Will your patch work for that version as well.

Regards

Raj

OtavioSalvador · ‎10-27-2014

No.

I just double checked and his patches didn't make 2014.01.

The pointers for the patches:

[U-Boot,1/4] ARM: armv7: Make indirect vector addresses globl - Patchwork

[U-Boot,V3,2/4] ARM: mx6: Add PCI express clock configuration - Patchwork

[U-Boot,V2,3/4] ARM: mx6: Add PCI express driver - Patchwork

[U-Boot,V2,4/4] ARM: mx6: Enable PCIe on Sabrelite - Patchwork

The 2014.10 is ever nicer so I suggest you to move for this version and enjoy a PCIe working support.

fabio_estevam · ‎10-27-2014

Yes, U-boot 2014.10 has PCI support 'out of the box' on mx6 sabresd boards.

lmhdoms · ‎01-23-2015

I take the liberty to append to this thread... I am trying to get SabreSD detect the Exar PCIe eval. board XR17V354. No luck with daisy (U-Boot or kernel 3.10.17). I tried with no PCI enabled in U-Boot, the kernel knows the PCIe root, but no device is detected (lspci lists only the root).

Reading this thread I have build the U-Boot 2014.10 to check if it can detect the eval. board. But it fails:

=> pci

Scanning PCI devices on bus 0

BusDevFun VendorId DeviceId Device Class Sub-Class

_____________________________________________________________

pci_bus_to_hose() failed

Am I missing something in the configuration? The power LED on the eval board lights up, so its not a power issue.

Thanks,

Lars

wallyyeh · ‎01-23-2015

Hi, Imhdoms:

the error message indicate that the board didn't get initialized correctly.

have you set the correct "CONFIG_PCIE_IMX_POWER_GPIO" and "CONFIG_PCIE_IMX_PERST_GPIO" in <u-boot dir>/include/configs/mx6sabresd.h ?

lmhdoms · ‎01-23-2015

Hi Wally,

I am using the mx6sabresd.h just as it is. This is the PCI part:

#define CONFIG_CMD_PCI

#ifdef CONFIG_CMD_PCI

#define CONFIG_PCI

#define CONFIG_PCI_PNP

#define CONFIG_PCI_SCAN_SHOW

#define CONFIG_PCIE_IMX

#define CONFIG_PCIE_IMX_PERST_GPIO IMX_GPIO_NR(7, 12)

#define CONFIG_PCIE_IMX_POWER_GPIO IMX_GPIO_NR(3, 19)

#endif

wallyyeh · ‎01-25-2015

Hi, Imhdoms:

that's weird. it should work for SabreSD board with this uboot.

maybe you should also ask on meta-freescale maillist, I think may Fabio know the answer.

sinanakman · ‎01-24-2014

Wally, if you do test his patches with mainline 2014.01 u-boot, please let me know what your findings are and I won't have to do the same thing.

Thanks

Sinan Akman

sinanakman · ‎01-24-2014

All good, thanks for all that.

-- sinan

OtavioSalvador · ‎01-24-2014

Yes; same patches I passed for Sinan as can be seen in the thread.

sinanakman · ‎01-24-2014

Hi Otavio, I am aware of his patches, I was just trying to see if anyone tested them on sabresd since last time I worked on this. It was not clear from your post whether you were referring to Marek patches or confirming that you tested them on sabresd. Wally said he had pcie working on sabresd but this wasn't mainline. So I assume you haven't tested Marek patches on sabresd too. Let me know if I misunderstood. I will then continue on trying to make Marek patches working on sabre sd.

Thanks

Sinan Akman