On Thu, Jun 20, 2019 at 08:27:15PM +0530, Manikanta Maddireddy wrote:
>
>
> On 20-Jun-19 8:02 PM, Lorenzo Pieralisi wrote:
> > On Tue, Jun 18, 2019 at 11:31:45PM +0530, Manikanta Maddireddy wrote:
> >> Tegra124, Tegra132, Tegra210 and Tegra186 support Gen2 link speed. After
> >> PCIe link is up in Gen1, set target link speed as Gen2 and retrain link.
> >> Link switches to Gen2 speed if Gen2 capable end point is connected, else
> >> link stays in Gen1.
> >>
> >> Per PCIe 4.0r0.9 sec 7.6.3.7 implementation note, driver need to wait for
> >> PCIe LTSSM to come back from recovery before retraining the link.
> >>
> >> Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
> >> Acked-by: Thierry Reding <treding@xxxxxxxxxx>
> >> ---
> >> V6: No change
> >>
> >> V5: No change
> >>
> >> V4: No change
> >>
> >> V3: Added blank line after each while loop.
> >>
> >> V2: Changed "for loop" to "while", to make it compact and handled coding
> >> style comments.
> >>
> >> drivers/pci/controller/pci-tegra.c | 64 ++++++++++++++++++++++++++++++
> >> 1 file changed, 64 insertions(+)
> >>
> >> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> >> index 5e9fcef5f8eb..5d19067f7193 100644
> >> --- a/drivers/pci/controller/pci-tegra.c
> >> +++ b/drivers/pci/controller/pci-tegra.c
> >> @@ -191,6 +191,8 @@
> >> #define RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE 0x20000000
> >> #define RP_LINK_CONTROL_STATUS_LINKSTAT_MASK 0x3fff0000
> >>
> >> +#define RP_LINK_CONTROL_STATUS_2 0x000000b0
> >> +
> >> #define PADS_CTL_SEL 0x0000009c
> >>
> >> #define PADS_CTL 0x000000a0
> >> @@ -226,6 +228,7 @@
> >> #define PADS_REFCLK_CFG_DRVI_SHIFT 12 /* 15:12 */
> >>
> >> #define PME_ACK_TIMEOUT 10000
> >> +#define LINK_RETRAIN_TIMEOUT 100000 /* in usec */
> >>
> >> struct tegra_msi {
> >> struct msi_controller chip;
> >> @@ -2089,6 +2092,64 @@ static bool tegra_pcie_port_check_link(struct tegra_pcie_port *port)
> >> return false;
> >> }
> >>
> >> +static void tegra_pcie_change_link_speed(struct tegra_pcie *pcie)
> >> +{
> >> + struct device *dev = pcie->dev;
> >> + struct tegra_pcie_port *port, *tmp;
> >> + ktime_t deadline;
> >> + u32 value;
> >> +
> >> + list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
> > And the reason to use the _safe version is ?
> >
> > Lorenzo
>
> This function is called in probe and resume_noirq. list entry is deleted in
> remove, I don't see any scenario where it can cause a race condition.
> It is fine to drop _safe. I will fix it in next version.
I will do it myself, it is not a fundamental issue, do not send another
version.
Thanks,
Lorenzo
