[U-Boot] [PATCH 15/23] pci: tegra: Add Tegra PCIe driver

[Stephen Warren]

On 08/20/2014 01:04 PM, Stephen Warren wrote:
> On 08/18/2014 01:16 AM, Thierry Reding wrote:
>> From: Thierry Reding <treding at nvidia.com>
>>
>> Add support for the PCIe controller found on some generations of Tegra.
>> Tegra20 has 2 root ports with a total of 4 lanes, Tegra30 has 3 root
>> ports with a total of 6 lanes and Tegra124 has 2 root ports with a total
>> of 5 lanes.
>
>> diff --git a/drivers/pci/pci_tegra.c b/drivers/pci/pci_tegra.c

>> +static bool tegra_pcie_port_check_link(struct tegra_pcie_port *port)
>> +{
>> +    unsigned int retries = 3;
>> +    unsigned long value;
>> +
>> +    value = rp_readl(port, RP_PRIV_MISC);
>> +    value &= ~RP_PRIV_MISC_PRSNT_MAP_EP_ABSNT;
>> +    value |= RP_PRIV_MISC_PRSNT_MAP_EP_PRSNT;
>> +    rp_writel(port, value, RP_PRIV_MISC);
>> +
>> +    do {
>> +        unsigned int timeout = 200;
>> +
>> +        do {
>> +            value = rp_readl(port, RP_VEND_XP);
>> +            if (value & RP_VEND_XP_DL_UP)
>> +                break;
>
> On my board, this almost never succeeds for Jetson TK1's built-in NIC,
> although it works fine for the mini-PCIe slot. On the other two boards I
> borrowed, this succeeds almost always. I'd prefer if we could get to the
> bottom of this before we actually apply this, although the bug is
> proving quite perplexing. The mainline kernel PCIe patches have the same
> issue.

I tracked the issue down to some missing pinmux configuration for the 
PCIe reset lane. With that in place, both U-Boot and the mainline Linux 
kernel PCIe support appear to work reliably. I'll work on patches to 
resolve that. So, I think we can go ahead and merge these patches 
without issue ASAP, as soon as any review comments are addressed.