On 09-May-19 7:40 PM, Thierry Reding wrote:
> On Tue, Apr 23, 2019 at 02:58:01PM +0530, Manikanta Maddireddy wrote:
>> Disable PCIe interrupts in runtime suspend to avoid executing irq handler
>> and power off sequence in parallel.
>>
>> Following sequence triggers such scenario,
>> - tegra_pcie_remove() triggers runtime suspend
>> - pex_rst is asserted in runtime suspend
>> - PRSNT_MAP bit field in RP_PRIV_MISC register changes from EP_PRSNT to
>> EP_ABSNT
>> - This is sensed by AFI and triggers "Slot present pin change" interrupt
>> - tegra_pcie_isr() function accesses AFI register when runtime suspend
>> is going through power off sequence
> This sounds like more of a workaround than a proper solution. If the
> above sequence crashes, it means that we have a bug somewhere in that
> sequence. By the time the controller is runtime suspended, we should
> have shut everything down already.
>
> That said, from the looks of it, I think we may be able to fix this by
> moving the pm_runtime_*() calls in tegra_pcie_remove() below the
> tegra_pcie_put_resources(). At that point, nothing should be accessing
> any registers anymore.
>
> Thierry
This crash is observed after applying 5/28 patch because,
- In the previous sequence AFI is asserted before PEX reset,
so AFI doesn't raise interrupt
- Whereas in 5/28 patch, PEX reset is asserted before AFI,
so AFI raises interrupt
I believe this patch is correct fix & not workaround because,
- tegra_pcie_pm_resume() -> tegra_pcie_enable_controller() is clearing
AFI_INTR_MASK
- In tegra_pcie_pm_suspend() this patch is doing opposite of above
programming, which is masking AFI_INTR_MASK
Moving pm_runtime_put() after tegra_pcie_put_resources() will not be
inline with init sequence in probe because tegra_pcie_get_resources()
is done before pm_runtime_get().
Manikanta
>> rmmod pci-tegra
>> pci_generic_config_write32: 108 callbacks suppressed
>> pci_bus 0002:00: 2-byte config write to 0002:00:02.0 offset 0x4c may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:02.0 offset 0x88 may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:02.0 offset 0x90 may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:02.0 offset 0x4 may corrupt adjacent RW1C bits
>> igb 0002:04:00.1: removed PHC on enP2p4s0f1
>> igb 0002:04:00.0: removed PHC on enP2p4s0f0
>> pci_bus 0002:00: 2-byte config write to 0002:00:01.0 offset 0x4c may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:01.0 offset 0x9c may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:01.0 offset 0x88 may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:01.0 offset 0x90 may corrupt adjacent RW1C bits
>> pci_bus 0002:00: 2-byte config write to 0002:00:01.0 offset 0x4 may corrupt adjacent RW1C bits
>> rcu: INFO: rcu_preempt self-detected stall on CPU
>> SError Interrupt on CPU0, code 0xbf000002 -- SError
>> CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.1.0-rc3-next-20190405-00027-gcd8110499e6f-dirty #42
>> Hardware name: NVIDIA Jetson TX1 Developer Kit (DT)
>> pstate: 20000085 (nzCv daIf -PAN -UAO)
>> pc : tegra_pcie_isr+0x58/0x178 [pci_tegra]
>> lr : tegra_pcie_isr+0x40/0x178 [pci_tegra]
>> sp : ffff000010003da0
>> x29: ffff000010003da0 x28: 0000000000000000
>> x27: ffff8000f9e61000 x26: ffff000010fbf420
>> x25: ffff000011427f93 x24: ffff8000fa600410
>> x23: ffff00001129d000 x22: ffff00001129d000
>> x21: ffff8000f18bf3c0 x20: 0000000000000070
>> x19: 00000000ffffffff x18: 0000000000000000
>> x17: 0000000000000000 x16: 0000000000000000
>> x15: 0000000000000000 x14: ffff000008d40a48
>> x13: ffff000008d40a30 x12: ffff000008d40a20
>> x11: ffff000008d40a10 x10: ffff000008d40a00
>> x9 : ffff000008d409e8 x8 : ffff000008d40ae8
>> x7 : ffff000008d40ad0 x6 : ffff000010003e58
>> x5 : ffff8000fac00248 x4 : 0000000000000000
>> x3 : ffff000008d40b08 x2 : fffffffffffffff8
>> x1 : ffff000008d3f4e8 x0 : 00000000ffffffff
>> Kernel panic - not syncing: Asynchronous SError Interrupt
>> CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.1.0-rc3-next-20190405-00027-gcd8110499e6f-dirty #42
>> Hardware name: NVIDIA Jetson TX1 Developer Kit (DT)
>> Call trace:
>> dump_backtrace+0x0/0x158
>> show_stack+0x14/0x20
>> dump_stack+0xa8/0xcc
>> panic+0x140/0x2f4
>> nmi_panic+0x6c/0x70
>> arm64_serror_panic+0x74/0x80
>> __pte_error+0x0/0x28
>> el1_error+0x84/0xf8
>> tegra_pcie_isr+0x58/0x178 [pci_tegra]
>> __handle_irq_event_percpu+0x70/0x198
>> handle_irq_event_percpu+0x34/0x88
>> handle_irq_event+0x48/0x78
>> handle_fasteoi_irq+0xb4/0x190
>> generic_handle_irq+0x24/0x38
>> __handle_domain_irq+0x5c/0xb8
>> gic_handle_irq+0x58/0xa8
>> el1_irq+0xb8/0x180
>> cpuidle_enter_state+0x138/0x358
>> cpuidle_enter+0x18/0x20
>> call_cpuidle+0x1c/0x48
>> do_idle+0x230/0x2d0
>> cpu_startup_entry+0x20/0x28
>> rest_init+0xd4/0xe0
>> arch_call_rest_init+0xc/0x14
>> start_kernel+0x444/0x470
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
>> ---
>> V2: This is new patch in V2
>>
>> drivers/pci/controller/pci-tegra.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
>> index bb3c0af9c830..8c0ad038699d 100644
>> --- a/drivers/pci/controller/pci-tegra.c
>> +++ b/drivers/pci/controller/pci-tegra.c
>> @@ -1622,6 +1622,18 @@ static int tegra_pcie_disable_msi(struct tegra_pcie *pcie)
>> return 0;
>> }
>>
>> +static void tegra_pcie_disable_interrupts(struct tegra_pcie *pcie)
>> +{
>> + u32 value;
>> +
>> + value = afi_readl(pcie, AFI_INTR_MASK);
>> + value &= ~AFI_INTR_MASK_INT_MASK;
>> + afi_writel(pcie, value, AFI_INTR_MASK);
>> +
>> + if (IS_ENABLED(CONFIG_PCI_MSI))
>> + tegra_pcie_disable_msi(pcie);
>> +}
>> +
>> static int tegra_pcie_get_xbar_config(struct tegra_pcie *pcie, u32 lanes,
>> u32 *xbar)
>> {
>> @@ -2466,6 +2478,11 @@ static int __maybe_unused tegra_pcie_pm_suspend(struct device *dev)
>> tegra_pcie_pme_turnoff(port);
>>
>> tegra_pcie_disable_ports(pcie);
>> + /*
>> + * disable interrupts to avoid executing irq handler in parallel
>> + * to power off sequence.
>> + */
>> + tegra_pcie_disable_interrupts(pcie);
>>
>> if (pcie->soc->program_uphy) {
>> err = tegra_pcie_phy_power_off(pcie);
>> --
>> 2.17.1
>>
