Hi Vignesh,
On 16/11/17 14:26, Vignesh R wrote:
> +linux-pci
>
> Hi Chris,
>
> On Thursday 16 November 2017 05:20 PM, Quadros, Roger wrote:
>> +Vignesh
>>
>> On 13/09/17 17:26, Chris Welch wrote:
>>> We are developing a product based on the TI AM5728 EVM. The product
>>> utilizes a TUSB7340 PCIe USB host for additional ports. The TUSB7340 is
>>> detected and setup properly and works OK with low data rate devices.
>>> However, hot plugging a Realtek USB network adapter and doing Ethernet
>>> transfer bandwidth testing using iperf3 causes the TUSB7340 host to be
>>> locked out. The TUSB7340 host appears to no longer communicate and the
>>> logging indicates xhci_hcd 0000:01:00.0: HC died; cleaning up. Same issue
>>> occurs with another USB Ethernet adapter I tried (Asus).
>>>
>>> We looked at using another host and found a mini PCIe card that utilizes
>>> the µPD720201 and can be directly installed on the TI AM5728 EVM. The card
>>> is detected properly and we reran the transfer test. The uPD720201 gets
>>> locks out with the same problem.
>>>
>>> The AM5728 testing was performed using the TI SD card stock
>>> am57xx-evm-linux-04.00.00.04.img, kernel am57xx-evm 4.9.28-geed43d1050, and
>>> it reports that it is using the TI AM572x EVM Rev A3 device tree.
>>>
>>> It shows the following logging when it fails (this is with the TI EVM and
>>> uPD720201).
>>>
>>> [ 630.400899] xhci_hcd 0000:01:00.0: xHCI host not responding to stop
>>> endpoint command.
>>> [ 630.408769] xhci_hcd 0000:01:00.0: Assuming host is dying, halting host.
>>> [ 630.420849] r8152 2-4:1.0 enp1s0u4: Tx status -108
>>> [ 630.425667] r8152 2-4:1.0 enp1s0u4: Tx status -108
>>> [ 630.430483] r8152 2-4:1.0 enp1s0u4: Tx status -108
>>> [ 630.435297] r8152 2-4:1.0 enp1s0u4: Tx status -108
>>> [ 630.440122] xhci_hcd 0000:01:00.0: HC died; cleaning up
>>> [ 630.453961] usb 2-4: USB disconnect, device number 2
>>>
>>> The problem appears to be a general driver issue given we get the same
>>> problem with both the TUSB7340 and the µPD720201.
>
> Seems like PCIe driver is missing MSI IRQs leading to stall.
> Reading xHCI registers via PCIe mem space confirms this.
>
> I see two problems wrt MSI handling:
> Since commit 8c934095fa2f3 ("PCI: dwc: Clear MSI interrupt status after it is
> handled, not before"),
> dwc clears MSI status after calling EP's IRQ handler. But, it happens that
> another MSI interrupt is
> raised just at the end of EP's IRQ handler and before clearing MSI status.
> This will result in loss of new MSI IRQ as we clear the MSI IRQ status
> without handling.
>
> Another problem appears to be wrt dra7xx PCIe wrapper:
> PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI does not seem to catch MSI IRQs unless,
> its ensured that PCIE_MSI_INTR0_STATUS register read returns 0.
>
> So, could you try reverting commit 8c934095fa2f3 and
> also apply below patch and let me know if that fixes the issue?
>
> -----------
>
> diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c
> index e77a4ceed74c..8280abc56f30 100644
> --- a/drivers/pci/dwc/pci-dra7xx.c
> +++ b/drivers/pci/dwc/pci-dra7xx.c
> @@ -259,10 +259,17 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq,
> void *arg)
> u32 reg;
>
> reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI);
> + dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg);
>
> switch (reg) {
> case MSI:
> - dw_handle_msi_irq(pp);
> + /*
> + * Need to make sure no MSI IRQs are pending before
> + * exiting handler, else the wrapper will not catch new
> + * IRQs. So loop around till dw_handle_msi_irq() returns
> + * IRQ_NONE
> + */
> + while (dw_handle_msi_irq(pp) != IRQ_NONE);
To avoid this kind of looping, shouldn't we be disabling all IRQ events while
the interrupt handler is running and enable them just before we return from the
hardirq
handler?
> break;
> case INTA:
> case INTB:
> @@ -273,8 +280,6 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq,
> void *arg)
> break;
> }
>
> - dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg);
> -
> return IRQ_HANDLED;
> }
>
>
>
>
--
cheers,
-roger
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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