[PATCH 6.12 504/826] PCI: tegra194: Move controller cleanups to pex_ep_event_pex_rst_deassert()

[PATCH 6.12 504/826] PCI: tegra194: Move controller cleanups to pex_ep_event_pex_rst_deassert()

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

[ Upstream commit 40e2125381dc11379112485e3eefdd25c6df5375 ]

Currently, the endpoint cleanup function dw_pcie_ep_cleanup() and EPF
deinit notify function pci_epc_deinit_notify() are called during the
execution of pex_ep_event_pex_rst_assert() i.e., when the host has asserted
PERST#. But quickly after this step, refclk will also be disabled by the
host.

All of the tegra194 endpoint SoCs supported as of now depend on the refclk
from the host for keeping the controller operational. Due to this
limitation, any access to the hardware registers in the absence of refclk
will result in a whole endpoint crash. Unfortunately, most of the
controller cleanups require accessing the hardware registers (like eDMA
cleanup performed in dw_pcie_ep_cleanup(), etc...). So these cleanup
functions can cause the crash in the endpoint SoC once host asserts PERST#.

One way to address this issue is by generating the refclk in the endpoint
itself and not depending on the host. But that is not always possible as
some of the endpoint designs do require the endpoint to consume refclk from
the host.

Thus, fix this crash by moving the controller cleanups to the start of
the pex_ep_event_pex_rst_deassert() function. This function is called
whenever the host has deasserted PERST# and it is guaranteed that the
refclk would be active at this point. So at the start of this function
(after enabling resources) the controller cleanup can be performed. Once
finished, rest of the code execution for PERST# deassert can continue as
usual.

Fixes: 473b2cf9c4d1 ("PCI: endpoint: Introduce 'epc_deinit' event and notify the EPF drivers")
Fixes: 570d7715eed8 ("PCI: dwc: ep: Introduce dw_pcie_ep_cleanup() API for drivers supporting PERST#")
Link: https://lore.kernel.org/r/20240817-pci-qcom-ep-cleanup-v1-2-d6b958226559@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Vidya Sagar <vidyas@nvidia.com>
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/controller/dwc/pcie-tegra194.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index c1394f2ab63ff..ced3b7e7bdade 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1704,9 +1704,6 @@ static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie)
 	if (ret)
 		dev_err(pcie->dev, "Failed to go Detect state: %d\n", ret);
 
-	pci_epc_deinit_notify(pcie->pci.ep.epc);
-	dw_pcie_ep_cleanup(&pcie->pci.ep);
-
 	reset_control_assert(pcie->core_rst);
 
 	tegra_pcie_disable_phy(pcie);
@@ -1785,6 +1782,10 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
 		goto fail_phy;
 	}
 
+	/* Perform cleanup that requires refclk */
+	pci_epc_deinit_notify(pcie->pci.ep.epc);
+	dw_pcie_ep_cleanup(&pcie->pci.ep);
+
 	/* Clear any stale interrupt statuses */
 	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
 	appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
-- 
2.43.0

Re: [PATCH 6.12 000/826] 6.12.2-rc1 review

[Jon Hunter]

On Tue, 03 Dec 2024 15:35:27 +0100, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 6.12.2 release.
> There are 826 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Thu, 05 Dec 2024 14:45:11 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.12.2-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.12.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

Failures detected for Tegra ...

Test results for stable-v6.12:
    10 builds:	10 pass, 0 fail
    26 boots:	26 pass, 0 fail
    116 tests:	115 pass, 1 fail

Linux version:	6.12.2-rc1-g1b3321bcbfba
Boards tested:	tegra124-jetson-tk1, tegra186-p2771-0000,
                tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
                tegra20-ventana, tegra210-p2371-2180,
                tegra210-p3450-0000, tegra30-cardhu-a04

Test failures:	tegra186-p2771-0000: pm-system-suspend.sh


Jon

Re: [PATCH 6.12 000/826] 6.12.2-rc1 review

[Jon Hunter]

On 05/12/2024 14:39, Jon Hunter wrote:
> On Tue, 03 Dec 2024 15:35:27 +0100, Greg Kroah-Hartman wrote:
>> This is the start of the stable review cycle for the 6.12.2 release.
>> There are 826 patches in this series, all will be posted as a response
>> to this one.  If anyone has any issues with these being applied, please
>> let me know.
>>
>> Responses should be made by Thu, 05 Dec 2024 14:45:11 +0000.
>> Anything received after that time might be too late.
>>
>> The whole patch series can be found in one patch at:
>> 	https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.12.2-rc1.gz
>> or in the git tree and branch at:
>> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.12.y
>> and the diffstat can be found below.
>>
>> thanks,
>>
>> greg k-h
> 
> Failures detected for Tegra ...
> 
> Test results for stable-v6.12:
>      10 builds:	10 pass, 0 fail
>      26 boots:	26 pass, 0 fail
>      116 tests:	115 pass, 1 fail
> 
> Linux version:	6.12.2-rc1-g1b3321bcbfba
> Boards tested:	tegra124-jetson-tk1, tegra186-p2771-0000,
>                  tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
>                  tegra20-ventana, tegra210-p2371-2180,
>                  tegra210-p3450-0000, tegra30-cardhu-a04
> 
> Test failures:	tegra186-p2771-0000: pm-system-suspend.sh


This is a known issue in the mainline that was not caught for Linux 
v6.12. It is intermittent and so not easily caught. The good news is 
that a fix [0] has been identified and once in mainline we can backport 
for stable. It is a networking issue that is causing random test 
failures when running with NFS.

With that for this update ...

Tested-by: Jon Hunter <jonathanh@nvidia.com>

Jon

[0] 
https://lore.kernel.org/netdev/20241205091830.3719609-1-0x1207@gmail.com/

-- 
nvpublic