DM8148EVM / AM3874 PCIe issue

Dennis McLeod

I have followed the document at http://processors.wiki.ti.com/index.php/TI81XX_PSP_PCI_Express_Root_Complex_Driver_User_Guide and in the TRM.

I am using EZSDK 05.04.00.11 (with Linux PSP-04.04.00.01).

I am trying to use PCIe as a RC device. According to the section http://processors.wiki.ti.com/index.php/TI81XX_PSP_PCI_Express_Root_Complex_Driver_User_Guide#Ensuring_PCIe_System_Initialization

I should see the embedded "PCI bridge: Texas Instruments Device b800", but I do not. I have config settings:

CONFIG_PCI=y
CONFIG_PCI_SYSCALL=y
CONFIG_ARCH_SUPPORTS_MSI=y
CONFIG_PCI_MSI=y
CONFIG_PCI_DEBUG=y

yet lcpci shows nothing, and nothing is in /sys/bus/pci/devices/

What is going wrong?

"dmesg | grep -i pci" output:

ti81xx_init_pcie[3026] registering ti81xx_pcie_device
PM: Adding info for platform:ti81xx_pcie.0
ti81xx_pcie: Invoking PCI BIOS...
ti81xx_pcie: Setting up Host Controller...
ti81xx_pcie: Register base mapped @0xe8820000
ti81xx_pcie: Starting PCI scan...
PM: Adding info for No Bus:pci0000:00
PCI: bus0: Fast back to back transfers enabled
pci_bus 0000:00: resource 0 [mem 0x20000000-0x2fffffff]
pci_bus 0000:00: resource 1 [io 0x40000000-0x402fffff]
PCI: CLS 0 bytes, default 64

Using a debugger pod, I halted the CPU and inspected PCIE_CFG register (@0x48140480):

AM387x-EVM>md 0x48140480 1
48140480 : 0x00000002 2 ....

Why don't I see the "PCI bridge: Texas Instruments Device b800" ?

over 13 years ago

0 Margarita Gashova over 13 years ago

TI__Guru* 80190 points

Hello,

The latest EZSDK version is 5.05.02 could you try with it.

Please make sure that you are follow the users guide presented in:

/ti-ezsdk_dm814x-evm_5_05_02_00/board-support/docs

TI81XX_PCI_Express_Endpoint_Boot_Driver_User_Guide.pdf

TI81XX_PCI_Express_Root_Complex_Driver_User_Guide.pdf

Best Regards,

Margarita

0 Dennis McLeod over 13 years ago in reply to Margarita Gashova

Intellectual 925 points

The documents you mention are exactly the document I said I followed in the original post

I have followed the document at http://processors.wiki.ti.com/index.php/TI81XX_PSP_PCI_Express_Root_Complex_Driver_User_Guide and in the TRM.

The PCIe RC driver document that shipped with the 5.04.00.11 indicates that it must have been working at the time it was written..(?)

I'd really like to find out what the problem is, rather than converting to a whole new tree in hopes that it just fixes it.

0 Margarita Gashova over 13 years ago

TI__Guru* 80190 points

Hello,

I am not the right person for PCIe.

Dennis McLeod said:
PM: Adding info for No Bus:pci0000:00
PCI: bus0: Fast back to back transfers enabled

But you could check this forum thread:

http://e2e.ti.com/support/embedded/linux/f/354/t/167329.aspx

Best Regards,

Margarita

0 Dennis McLeod over 13 years ago in reply to Margarita Gashova

Intellectual 925 points

That looks promising! I will check those suggestions out.

Thank you!

0 Dennis McLeod over 13 years ago in reply to Margarita Gashova

Intellectual 925 points

Does anyone know if there has to be something connected downstream for the TI PCIE RC bridge to be visible (found in the pci scan)? Or should it show up always?

0 Dennis McLeod over 13 years ago in reply to Dennis McLeod

Intellectual 925 points

update:

From that other thread, Hemant says:

1) Verify power up sequence, since XIO will be taking refclock from the EVM slot, recommended sequence would be EVM -> XIO -> PCI devices (if they need external power). Also confirm if indeed the refclock for XIO is received from slot.

2) Note that, as mentioned in the RC driver user guide, the EVM may have a bug where PERSTn always remains low, while ideally we should have default low and toggle to high before starting enumeration in which case, the above sequence would not matter. Else, ensure that SW5-1 is set as input or at least the pin remains high always.

3) Also provide the dump of register 0x51001728 which would show us link status. In success case, the LS 5 bits value should be 0x11.

Item #2 applies only to the 8168EVM, I am using the 8148EVM.

Item #3, I do have bits 1:0 == b11 (link up) :

AM387x-EVM>md 0x51001728
51001728 : 00004a03 08000000 00000000 00000000 .J..............

I have not verified REFCLK (item #1) yet.

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DM8148EVM / AM3874 PCIe issue