linux-kernel - Re: [PATCH v6 04/18] PCI: designware-ep: Pre-allocate memory for MSI in dw_pcie_ep

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Message-ID: <690a6c50-f5af-24bb-2f49-ba828022dcee@synopsys.com>
Date:   Wed, 20 Dec 2017 19:30:06 +0000
From:   Joao Pinto <Joao.Pinto@...opsys.com>
To:     Niklas Cassel <niklas.cassel@...s.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Joao Pinto <Joao.Pinto@...opsys.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>
CC:     Niklas Cassel <niklass@...s.com>, <linux-pci@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 04/18] PCI: designware-ep: Pre-allocate memory for MSI
 in dw_pcie_ep_init


Hi,

Às 11:29 PM de 12/19/2017, Niklas Cassel escreveu:
> Certain SoCs need to map the MSI address in raise_irq.
> To map an address, you first need to call pci_epc_mem_alloc_addr(),
> however, pci_epc_mem_alloc_addr() calls ioremap() (which can sleep).
> 
> Since raise_irq is only called from atomic context, we can't call
> pci_epc_mem_alloc_addr() from raise_irq.
> 
> Pre-allocate a page in dw_pcie_ep_init(), so that this page can later
> be used to map/unmap the MSI address in raise_irq.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@...s.com>
> ---
>  drivers/pci/dwc/pcie-designware-ep.c | 10 ++++++++++
>  drivers/pci/dwc/pcie-designware.h    |  2 ++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
> index 3fb34be99715..8d8019cdff2a 100644
> --- a/drivers/pci/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/dwc/pcie-designware-ep.c
> @@ -286,6 +286,9 @@ void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>  {
>  	struct pci_epc *epc = ep->epc;
>  
> +	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> +			      epc->mem->page_size);
> +
>  	pci_epc_mem_exit(epc);
>  }
>  
> @@ -341,6 +344,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>  		return ret;
>  	}
>  
> +	ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
> +					     epc->mem->page_size);
> +	if (!ep->msi_mem) {
> +		dev_err(dev, "Failed to reserve memory for MSI\n");
> +		return -ENOMEM;
> +	}
> +
>  	ep->epc = epc;
>  	epc_set_drvdata(epc, ep);
>  	dw_pcie_setup(pci);
> diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
> index 9aaf0cd04dd6..5a1da459eda5 100644
> --- a/drivers/pci/dwc/pcie-designware.h
> +++ b/drivers/pci/dwc/pcie-designware.h
> @@ -198,6 +198,8 @@ struct dw_pcie_ep {
>  	unsigned long		ob_window_map;
>  	u32			num_ib_windows;
>  	u32			num_ob_windows;
> +	void __iomem		*msi_mem;
> +	phys_addr_t		msi_mem_phys;
>  };
>  
>  struct dw_pcie_ops {
> 

Acked-by: Joao Pinto <jpinto@...opsys.com>