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

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Date:   Thu, 21 Dec 2017 11:46:06 -0500
From:   "Jingoo Han" <jingoohan1@...il.com>
To:     "'Joao Pinto'" <Joao.Pinto@...opsys.com>,
        "'Niklas Cassel'" <niklas.cassel@...s.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

On Wednesday, December 20, 2017 2:30 PM, Joao Pinto wrote:
> 
> 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>

Acked-by: Jingoo Han <jingoohan1@...il.com>

Best regards,
Jingoo Han