From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Niklas Cassel <cassel@kernel.org>
Cc: "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, mhi@lists.linux.dev,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH 05/11] PCI: epf-{mhi/test}: Move DMA initialization to EPC init callback
Date: Tue, 26 Mar 2024 13:56:36 +0530 [thread overview]
Message-ID: <20240326082636.GG9565@thinkpad> (raw)
In-Reply-To: <Zf2tXgKo-gc3qy1D@ryzen>
On Fri, Mar 22, 2024 at 05:10:06PM +0100, Niklas Cassel wrote:
> On Thu, Mar 14, 2024 at 08:53:44PM +0530, Manivannan Sadhasivam wrote:
> > To maintain uniformity across EPF drivers, let's move the DMA
> > initialization to EPC init callback. This will also allow us to deinit DMA
> > during PERST# assert in the further commits.
> >
> > For EPC drivers without PERST#, DMA deinit will only happen during driver
> > unbind.
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
>
> Reviewed-by: Niklas Cassel <cassel@kernel.org>
>
>
> For the record, I was debugging a problem related to EPF DMA recently
> and was dumping the DMA mask for the struct device of the epf driver.
> I was a bit confused to see it as 32-bits, even though the EPC driver
> has it set to 64-bits.
>
> The current code works, because e.g., pci_epf_test_write(), etc,
> does:
> struct device *dma_dev = epf->epc->dev.parent;
> dma_map_single(dma_dev, ...);
>
> but it also means that all EPF drivers will do this uglyness.
>
This ugliness is required as long as the dmaengine is associated only with the
EPC.
>
>
> However, if a EPF driver does e.g.
> dma_alloc_coherent(), and sends in the struct *device for the EPF,
> which is the most logical thing to do IMO, it will use the wrong DMA
> mask.
>
> Perhaps EPF or EPC code should make sure that the struct *device
> for the EPF will get the same DMA mask as epf->epc->dev.parent,
> so that EPF driver developer can use the struct *epf when calling
> e.g. dma_alloc_coherent().
>
Makes sense. I think it can be done during bind() in the EPC core. Feel free to
submit a patch if you like, otherwise I'll keep it in my todo list.
- Mani
--
மணிவண்ணன் சதாசிவம்
next prev parent reply other threads:[~2024-03-26 8:26 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 15:23 [PATCH 00/11] PCI: endpoint: Make host reboot handling more robust Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 01/11] PCI: qcom-ep: Disable resources unconditionally during PERST# assert Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:44 ` Manivannan Sadhasivam
2024-03-26 10:24 ` Niklas Cassel
2024-03-26 11:10 ` Manivannan Sadhasivam
2024-03-26 13:47 ` Niklas Cassel
2024-03-26 13:55 ` Manivannan Sadhasivam
2024-03-26 10:37 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 02/11] PCI: endpoint: Decouple EPC and PCIe bus specific events Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:49 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 03/11] PCI: endpoint: Rename core_init() callback in 'struct pci_epc_event_ops' to init() Manivannan Sadhasivam
2024-03-22 16:08 ` Niklas Cassel
2024-03-26 7:56 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 04/11] PCI: epf-test: Refactor pci_epf_test_unbind() function Manivannan Sadhasivam
2024-03-22 16:09 ` Niklas Cassel
2024-03-26 7:58 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 05/11] PCI: epf-{mhi/test}: Move DMA initialization to EPC init callback Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:26 ` Manivannan Sadhasivam [this message]
2024-03-26 11:05 ` Niklas Cassel
2024-03-26 14:27 ` Niklas Cassel
2024-03-27 6:20 ` Manivannan Sadhasivam
2024-03-27 6:18 ` Manivannan Sadhasivam
2024-03-27 11:39 ` Niklas Cassel
2024-03-28 18:42 ` Vinod Koul
2024-04-04 8:44 ` Niklas Cassel
2024-04-22 7:55 ` Manivannan Sadhasivam
2024-04-22 9:30 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 06/11] PCI: endpoint: Introduce EPC 'deinit' event and notify the EPF drivers Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:31 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 07/11] PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle Link Down event Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-27 18:06 ` Niklas Cassel
2024-04-01 16:34 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 08/11] PCI: qcom-ep: Use the " Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 09/11] PCI: epf-test: Handle " Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-14 15:23 ` [PATCH 10/11] PCI: qcom-ep: Rework {start/stop}_link() callbacks implementation Manivannan Sadhasivam
2024-03-22 16:10 ` Niklas Cassel
2024-03-26 8:33 ` Manivannan Sadhasivam
2024-03-14 15:23 ` [PATCH 11/11] PCI: tegra194: " Manivannan Sadhasivam
2024-03-22 16:11 ` Niklas Cassel
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