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Date: Thu, 7 Mar 2024 21:14:11 +0100
From: Niklas Cassel <cassel@kernel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>,
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	linux-arm-kernel@axis.com, Frank Li <Frank.Li@nxp.com>
Subject: Re: [PATCH v9 03/10] PCI: dwc: ep: Introduce dw_pcie_ep_cleanup()
 API for drivers supporting PERST#
Message-ID: <ZeogExV6wbNdpdEA@ryzen>
References: <20240304-pci-dbi-rework-v9-0-29d433d99cda@linaro.org>
 <20240304-pci-dbi-rework-v9-3-29d433d99cda@linaro.org>
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In-Reply-To: <20240304-pci-dbi-rework-v9-3-29d433d99cda@linaro.org>

On Mon, Mar 04, 2024 at 02:52:15PM +0530, Manivannan Sadhasivam wrote:
> For DWC glue drivers supporting PERST# (currently Qcom and Tegra194), some
> of the DWC resources like eDMA should be cleaned up during the PERST#
> assert time.
> 
> So let's introduce a dw_pcie_ep_cleanup() API that could be called by these
> drivers to cleanup the DWC specific resources. Currently, it just removes
> eDMA.
> 
> Reported-by: Niklas Cassel <cassel@kernel.org>
> Closes: https://lore.kernel.org/linux-pci/ZWYmX8Y%2F7Q9WMxES@x1-carbon
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-designware-ep.c | 11 +++++++++--
>  drivers/pci/controller/dwc/pcie-designware.h    |  5 +++++
>  drivers/pci/controller/dwc/pcie-qcom-ep.c       |  1 +
>  drivers/pci/controller/dwc/pcie-tegra194.c      |  2 ++
>  4 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 2b11290aab4c..1205bfba8310 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -564,12 +564,19 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>  	return 0;
>  }
>  
> -void dw_pcie_ep_deinit(struct dw_pcie_ep *ep)
> +void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> -	struct pci_epc *epc = ep->epc;
>  
>  	dw_pcie_edma_remove(pci);
> +}
> +EXPORT_SYMBOL_GPL(dw_pcie_ep_cleanup);

Since you are not clearing the iATU bits in ep->ib_window_map and
ep->bar_to_atu, this will "leak" resources, so depending on how many
inbound iATUs the platform has, by simply the RC toggling PERST,
will cause an error when calling set_bar() after dw_pcie_ep_init_notify().

However, because you have said that you will address this in a follow up
series:
Reviewed-by: Niklas Cassel <cassel@kernel.org>