Date: Wed, 27 Mar 2024 09:24:05 +0100
From: Niklas Cassel <cassel@...nel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: Jingoo Han <jingoohan1@...il.com>,
	Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
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	Heiko Stuebner <heiko@...ech.de>, linux-pci@...r.kernel.org,
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Subject: Re: [PATCH v11 8/8] PCI: endpoint: Remove "core_init_notifier" flag

Hello Mani,

On Wed, Mar 27, 2024 at 12:05:54PM +0530, Manivannan Sadhasivam wrote:
> "core_init_notifier" flag is set by the glue drivers requiring refclk from
> the host to complete the DWC core initialization. Also, those drivers will
> send a notification to the EPF drivers once the initialization is fully
> completed using the pci_epc_init_notify() API. Only then, the EPF drivers
> will start functioning.
> 
> For the rest of the drivers generating refclk locally, EPF drivers will
> start functioning post binding with them. EPF drivers rely on the
> 'core_init_notifier' flag to differentiate between the drivers.
> Unfortunately, this creates two different flows for the EPF drivers.
> 
> So to avoid that, let's get rid of the "core_init_notifier" flag and follow
> a single initialization flow for the EPF drivers. This is done by calling
> the dw_pcie_ep_init_notify() from all glue drivers after the completion of
> dw_pcie_ep_init_registers() API. This will allow all the glue drivers to
> send the notification to the EPF drivers once the initialization is fully
> completed.
> 
> Only difference here is that, the drivers requiring refclk from host will
> send the notification once refclk is received, while others will send it
> during probe time itself.
> 
> But this also requires the EPC core driver to deliver the notification
> after EPF driver bind. Because, the glue driver can send the notification
> before the EPF drivers bind() and in those cases the EPF drivers will miss
> the event. To accommodate this, EPC core is now caching the state of the
> EPC initialization in 'init_complete' flag and pci-ep-cfs driver sends the
> notification to EPF drivers based on that after each EPF driver bind.
> 
> Tested-by: Niklas Cassel <cassel@...nel.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> ---
>  drivers/pci/controller/cadence/pcie-cadence-ep.c  |  2 ++
>  drivers/pci/controller/dwc/pci-dra7xx.c           |  2 ++
>  drivers/pci/controller/dwc/pci-imx6.c             |  2 ++
>  drivers/pci/controller/dwc/pci-keystone.c         |  2 ++
>  drivers/pci/controller/dwc/pci-layerscape-ep.c    |  2 ++
>  drivers/pci/controller/dwc/pcie-artpec6.c         |  2 ++
>  drivers/pci/controller/dwc/pcie-designware-ep.c   |  1 +
>  drivers/pci/controller/dwc/pcie-designware-plat.c |  2 ++
>  drivers/pci/controller/dwc/pcie-keembay.c         |  2 ++
>  drivers/pci/controller/dwc/pcie-qcom-ep.c         |  1 -
>  drivers/pci/controller/dwc/pcie-rcar-gen4.c       |  2 ++
>  drivers/pci/controller/dwc/pcie-tegra194.c        |  1 -
>  drivers/pci/controller/dwc/pcie-uniphier-ep.c     |  2 ++
>  drivers/pci/controller/pcie-rcar-ep.c             |  2 ++
>  drivers/pci/controller/pcie-rockchip-ep.c         |  2 ++
>  drivers/pci/endpoint/functions/pci-epf-test.c     | 18 +++++-------------
>  drivers/pci/endpoint/pci-ep-cfs.c                 |  9 +++++++++
>  drivers/pci/endpoint/pci-epc-core.c               | 22 ++++++++++++++++++++++
>  include/linux/pci-epc.h                           |  7 ++++---
>  19 files changed, 65 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
> index 2d0a8d78bffb..da67a06ee790 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
> @@ -734,6 +734,8 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep)
>  
>  	spin_lock_init(&ep->lock);
>  
> +	dw_pcie_ep_init_notify(&pci->ep);

This looks wrong (and I think that you have not build tested this).

dw_* prefix indicates DWC, so it is a DWC specific function.

I don't think that you can use this function for the 3 non-DWC EPC drivers.
I think that you need to use call pci_epc_init_notify() directly.


(Also perhaps rebase your series on v6.9-rc1, I got conflicts when trying
to apply it to v6.9-rc1, because it looks like the series is still based
on v6.8-rc1.)


Kind regards,
Niklas

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