Re: [PATCH v3 01/14] PCI: tegra: Convert to MSI domains

[Jon Hunter <jonathanh@nvidia.com>]

On 19/04/2021 20:19, Jon Hunter wrote:
> Hi Marc,
> 
> On 30/03/2021 16:11, Marc Zyngier wrote:
>> In anticipation of the removal of the msi_controller structure, convert
>> the Tegra host controller driver to MSI domains.
>>
>> We end-up with the usual two domain structure, the top one being a
>> generic PCI/MSI domain, the bottom one being Tegra-specific and handling
>> the actual HW interrupt allocation.
>>
>> While at it, convert the normal interrupt handler to a chained handler,
>> handle the controller's MSI IRQ edge triggered, support multiple MSIs
>> per device and use the AFI_MSI_EN_VEC* registers to provide MSI masking.
>>
>> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>> [treding@nvidia.com: fix, clean up and address TODOs from Marc's draft]
>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
> 
> 
> This change is breaking a suspend test that we are running on Tegra124
> Jetson-TK1. The Tegra124 Jetson TK1 uses a PCI based ethernet device ...
> 
> $ lspci
> 00:02.0 PCI bridge: NVIDIA Corporation TegraK1 PCIe x1 Bridge (rev a1)
> 01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
> RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)
> 
> After resuming from suspend, networking is no longer working. The reason
> why this breaks our suspend test is because that setup is using NFS for
> the rootfs. I am looking into it, but if anyone has any thoughts please
> let me know.


So the following does appear to fix it ...

diff --git a/drivers/pci/controller/pci-tegra.c
b/drivers/pci/controller/pci-tegra.c
index eaba7b2fab4a..558f02e0693d 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -1802,13 +1802,17 @@ static void tegra_pcie_enable_msi(struct
tegra_pcie *pcie)
 {
        const struct tegra_pcie_soc *soc = pcie->soc;
        struct tegra_msi *msi = &pcie->msi;
-       u32 reg;
+       u32 i, reg;

        afi_writel(pcie, msi->phys >> soc->msi_base_shift,
AFI_MSI_FPCI_BAR_ST);
        afi_writel(pcie, msi->phys, AFI_MSI_AXI_BAR_ST);
        /* this register is in 4K increments */
        afi_writel(pcie, 1, AFI_MSI_BAR_SZ);

+       /* enable all MSI vectors */
+       for (i = 0; i < 8; i++)
+               afi_writel(pcie, 0xffffffff, AFI_MSI_EN_VEC(i));
+
        /* and unmask the MSI interrupt */
        reg = afi_readl(pcie, AFI_INTR_MASK);
        reg |= AFI_INTR_MASK_MSI_MASK;
@@ -1837,13 +1841,17 @@ static void tegra_pcie_msi_teardown(struct
tegra_pcie *pcie)

 static int tegra_pcie_disable_msi(struct tegra_pcie *pcie)
 {
-       u32 value;
+       u32 i, value;

        /* mask the MSI interrupt */
        value = afi_readl(pcie, AFI_INTR_MASK);
        value &= ~AFI_INTR_MASK_MSI_MASK;
        afi_writel(pcie, value, AFI_INTR_MASK);

+       /* disable all MSI vectors */
+       for (i = 0; i < 8; i++)
+               afi_writel(pcie, 0, AFI_MSI_EN_VEC(i));
+
        return 0;
 }


Any reason why that code was removed?

Thanks
Jon

-- 
nvpublic