Re: [PATCH RESEND v3 07/10] PCI: visconti: Convert to using generic resources getter

Serge Semin
2023-04-11T17:10:45Z

On Tue, Apr 11, 2023 at 04:49:47PM +0530, Manivannan Sadhasivam wrote:
> On Tue, Apr 11, 2023 at 06:39:25AM +0300, Serge Semin wrote:
> > The generic resources request infrastructure has been recently added to
> > the DW PCIe core driver. Since the DT-bindings of the Toshibo Visconti
> > PCIe Host controller is fully compatible with the generic names set let's
> > convert the driver to using that infrastructure. It won't take much effort
> > since the low-level device driver implies the resources request only with
> > no additional manipulations involving them. So just drop the locally
> > defined clocks request procedures, activate the generic resources request
> > capability and make sure the mandatory resources have been requested by
> > the DW PCIe core driver.
> >
> > Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > ---
> > drivers/pci/controller/dwc/pcie-visconti.c | 37 ++++++++++------------
> > 1 file changed, 17 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-visconti.c b/drivers/pci/controller/dwc/pcie-visconti.c
> > index 71026fefa366..ae1517b52c58 100644
> > --- a/drivers/pci/controller/dwc/pcie-visconti.c
> > +++ b/drivers/pci/controller/dwc/pcie-visconti.c
> > @@ -29,9 +29,6 @@ struct visconti_pcie {
> > void __iomem *ulreg_base;
> > void __iomem *smu_base;
> > void __iomem *mpu_base;
> > - struct clk *refclk;
> > - struct clk *coreclk;
> > - struct clk *auxclk;
> > };
> >
> > #define PCIE_UL_REG_S_PCIE_MODE 0x00F4
> > @@ -198,6 +195,21 @@ static int visconti_pcie_host_init(struct dw_pcie_rp *pp)
> > int err;
> > u32 val;
> >
> > + if (!pcie->pci.core_clks[DW_PCIE_REF_CLK].clk) {
> > + dev_err(pci->dev, "Missing ref clock source\n");
> > + return -ENOENT;
> > + }
> > +
> > + if (!pcie->pci.core_clks[DW_PCIE_CORE_CLK].clk) {
> > + dev_err(pci->dev, "Missing core clock source\n");
> > + return -ENOENT;
> > + }
> > +
> > + if (!pcie->pci.core_clks[DW_PCIE_AUX_CLK].clk) {
> > + dev_err(pci->dev, "Missing aux clock source\n");
> > + return -ENOENT;
> > + }
> > +
>
> Looking at the driver, I could see no call to clk_prepare_enable() for these
> clocks. So from kernel's PoV these are not used at all. So either these clocks
> are not required (unlikely) or enabled by the bootloader so kernel just uses it.
>
> In that case, the driver should handle these clocks properly.
>
> @Nobuhiro-San, can you please comment?

I will easily update the patch with a code enabling these clocks in
the visconti_pcie_host_init() method if @Nobuhiro-San are ok with
that.

-Serge(y)

>
> - Mani
>
> > visconti_smu_writel(pcie,
> > PISMU_CKON_PCIE_AUX_CLK | PISMU_CKON_PCIE_MSTR_ACLK,
> > PISMU_CKON_PCIE);
> > @@ -242,8 +254,6 @@ static const struct dw_pcie_host_ops visconti_pcie_host_ops = {
> > static int visconti_get_resources(struct platform_device *pdev,
> > struct visconti_pcie *pcie)
> > {
> > - struct device *dev = &pdev->dev;
> > -
> > pcie->ulreg_base = devm_platform_ioremap_resource_byname(pdev, "ulreg");
> > if (IS_ERR(pcie->ulreg_base))
> > return PTR_ERR(pcie->ulreg_base);
> > @@ -256,21 +266,6 @@ static int visconti_get_resources(struct platform_device *pdev,
> > if (IS_ERR(pcie->mpu_base))
> > return PTR_ERR(pcie->mpu_base);
> >
> > - pcie->refclk = devm_clk_get(dev, "ref");
> > - if (IS_ERR(pcie->refclk))
> > - return dev_err_probe(dev, PTR_ERR(pcie->refclk),
> > - "Failed to get ref clock\n");
> > -
> > - pcie->coreclk = devm_clk_get(dev, "core");
> > - if (IS_ERR(pcie->coreclk))
> > - return dev_err_probe(dev, PTR_ERR(pcie->coreclk),
> > - "Failed to get core clock\n");
> > -
> > - pcie->auxclk = devm_clk_get(dev, "aux");
> > - if (IS_ERR(pcie->auxclk))
> > - return dev_err_probe(dev, PTR_ERR(pcie->auxclk),
> > - "Failed to get aux clock\n");
> > -
> > return 0;
> > }
> >
> > @@ -304,6 +299,8 @@ static int visconti_pcie_probe(struct platform_device *pdev)
> > pci->dev = dev;
> > pci->ops = &dw_pcie_ops;
> >
> > + dw_pcie_cap_set(pci, REQ_RES);
> > +
> > ret = visconti_get_resources(pdev, pcie);
> > if (ret)
> > return ret;
> > --
> > 2.40.0
> >
> >
>
> --
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