Hello Serge,
> From: Serge Semin, Sent: Monday, September 25, 2023 7:53 PM
> To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> Cc: lpieralisi@xxxxxxxxxx; kw@xxxxxxxxx; robh@xxxxxxxxxx; bhelgaas@xxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx;
> conor+dt@xxxxxxxxxx; jingoohan1@xxxxxxxxx; gustavo.pimentel@xxxxxxxxxxxx; mani@xxxxxxxxxx;
> marek.vasut+renesas@xxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-renesas-soc@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v22 14/16] PCI: dwc: rcar-gen4: Add R-Car Gen4 PCIe Endpoint support
>
> On Mon, Sep 25, 2023 at 04:21:28PM +0900, Yoshihiro Shimoda wrote:
> > Add R-Car Gen4 PCIe controller for endpoint mode. This controller is based
> > on Synopsys DesignWare PCIe.
> >
> > Link:
<snip>
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > Signed-off-by: Krzysztof Wilczyński <kwilczynski@xxxxxxxxxx>
> > Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> > ---
> > drivers/pci/controller/dwc/Kconfig | 11 ++
> > drivers/pci/controller/dwc/pcie-rcar-gen4.c | 136 +++++++++++++++++++-
> > 2 files changed, 144 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> > index bc69fcab2e2a..e7fd37717998 100644
> > --- a/drivers/pci/controller/dwc/Kconfig
> > +++ b/drivers/pci/controller/dwc/Kconfig
> > @@ -429,4 +429,15 @@ config PCIE_RCAR_GEN4_HOST
> > To compile this driver as a module, choose M here: the module will be
> > called pcie-rcar-gen4.ko. This uses the DesignWare core.
> >
> > +config PCIE_RCAR_GEN4_EP
> > + tristate "Renesas R-Car Gen4 PCIe controller (endpoint mode)"
> > + depends on ARCH_RENESAS || COMPILE_TEST
> > + depends on PCI_ENDPOINT
> > + select PCIE_DW_EP
> > + select PCIE_RCAR_GEN4
> > + help
> > + Say Y here if you want PCIe controller (endpoint mode) on R-Car Gen4
> > + SoCs. To compile this driver as a module, choose M here: the module
> > + will be called pcie-rcar-gen4.ko. This uses the DesignWare core.
> > +
> > endmenu
> > diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > index f6b3c3ef187c..d1b31ea909ba 100644
> > --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > @@ -45,6 +45,9 @@
> > #define RCAR_NUM_SPEED_CHANGE_RETRIES 10
> > #define RCAR_MAX_LINK_SPEED 4
> >
> > +#define RCAR_GEN4_PCIE_EP_FUNC_DBI_OFFSET 0x1000
> > +#define RCAR_GEN4_PCIE_EP_FUNC_DBI2_OFFSET 0x800
> > +
> > struct rcar_gen4_pcie {
> > struct dw_pcie dw;
> > void __iomem *base;
> > @@ -53,6 +56,7 @@ struct rcar_gen4_pcie {
> > };
> > #define to_rcar_gen4_pcie(_dw) container_of(_dw, struct rcar_gen4_pcie, dw)
> >
> > +/* Common */
> > static void rcar_gen4_pcie_ltssm_enable(struct rcar_gen4_pcie *rcar,
> > bool enable)
> > {
> > @@ -311,6 +315,9 @@ static int rcar_gen4_add_dw_pcie_rp(struct rcar_gen4_pcie *rcar)
> > {
> > struct dw_pcie_rp *pp = &rcar->dw.pp;
> >
> > + if (!IS_ENABLED(CONFIG_PCIE_RCAR_GEN4_HOST))
> > + return -ENODEV;
> > +
> > pp->num_vectors = MAX_MSI_IRQS;
> > pp->ops = &rcar_gen4_pcie_host_ops;
> > rcar->mode = DW_PCIE_RC_TYPE;
> > @@ -323,8 +330,114 @@ static void rcar_gen4_remove_dw_pcie_rp(struct rcar_gen4_pcie *rcar)
> > dw_pcie_host_deinit(&rcar->dw.pp);
> > }
> >
> > +/* Endpoind mode */
> > +static void rcar_gen4_pcie_ep_pre_init(struct dw_pcie_ep *ep)
> > +{
> > + struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
> > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> > + int ret;
> > +
> > + ret = rcar_gen4_pcie_common_init(rcar);
> > + if (ret)
> > + return;
> > +
> > + writel(PCIEDMAINTSTSEN_INIT, rcar->base + PCIEDMAINTSTSEN);
> > +}
> > +
> > +static void rcar_gen4_pcie_ep_init(struct dw_pcie_ep *ep)
> > +{
> > + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > + enum pci_barno bar;
> > +
> > + for (bar = 0; bar < PCI_STD_NUM_BARS; bar++)
> > + dw_pcie_ep_reset_bar(pci, bar);
> > +}
> > +
> > +static void rcar_gen4_pcie_ep_deinit(struct dw_pcie_ep *ep)
> > +{
> > + struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
> > + struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> > +
> > + writel(0, rcar->base + PCIEDMAINTSTSEN);
> > + rcar_gen4_pcie_common_deinit(rcar);
> > +}
> > +
> > +static int rcar_gen4_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> > + unsigned int type, u16 interrupt_num)
> > +{
> > + struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
> > +
> > + switch (type) {
> > + case PCI_IRQ_LEGACY:
> > + return dw_pcie_ep_raise_legacy_irq(ep, func_no);
> > + case PCI_IRQ_MSI:
> > + return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> > + default:
> > + dev_err(dw->dev, "Unknown IRQ type\n");
> > + return -EINVAL;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct pci_epc_features rcar_gen4_pcie_epc_features = {
> > + .linkup_notifier = false,
> > + .msi_capable = true,
> > + .msix_capable = false,
> > + .reserved_bar = 1 << BAR_1 | 1 << BAR_3 | 1 << BAR_5,
> > + .align = SZ_1M,
> > +};
> > +
> > +static const struct pci_epc_features*
> > +rcar_gen4_pcie_ep_get_features(struct dw_pcie_ep *ep)
> > +{
> > + return &rcar_gen4_pcie_epc_features;
> > +}
> > +
> > +static unsigned int rcar_gen4_pcie_ep_func_conf_select(struct dw_pcie_ep *ep,
> > + u8 func_no)
> > +{
> > + return func_no * RCAR_GEN4_PCIE_EP_FUNC_DBI_OFFSET;
> > +}
> > +
> > +static unsigned int rcar_gen4_pcie_ep_get_dbi2_offset(struct dw_pcie_ep *ep,
> > + u8 func_no)
> > +{
> > + return func_no * RCAR_GEN4_PCIE_EP_FUNC_DBI2_OFFSET;
> > +}
> > +
> > +static const struct dw_pcie_ep_ops pcie_ep_ops = {
> > + .pre_init = rcar_gen4_pcie_ep_pre_init,
> > + .ep_init = rcar_gen4_pcie_ep_init,
> > + .deinit = rcar_gen4_pcie_ep_deinit,
> > + .raise_irq = rcar_gen4_pcie_ep_raise_irq,
> > + .get_features = rcar_gen4_pcie_ep_get_features,
> > + .func_conf_select = rcar_gen4_pcie_ep_func_conf_select,
> > + .get_dbi2_offset = rcar_gen4_pcie_ep_get_dbi2_offset,
> > +};
> > +
> > +static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
> > +{
> > + struct dw_pcie_ep *ep = &rcar->dw.ep;
> > +
> > + if (!IS_ENABLED(CONFIG_PCIE_RCAR_GEN4_EP))
> > + return -ENODEV;
> > +
> > + rcar->mode = DW_PCIE_EP_TYPE;
> > + ep->ops = &pcie_ep_ops;
> > +
> > + return dw_pcie_ep_init(ep);
> > +}
> > +
> > +static void rcar_gen4_remove_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
> > +{
> > + dw_pcie_ep_exit(&rcar->dw.ep);
> > +}
> > +
> > +/* Common */
> > static int rcar_gen4_pcie_probe(struct platform_device *pdev)
> > {
> > + enum dw_pcie_device_mode mode;
> > struct rcar_gen4_pcie *rcar;
> > int err;
> >
> > @@ -340,7 +453,13 @@ static int rcar_gen4_pcie_probe(struct platform_device *pdev)
> > if (err)
> > return err;
> >
>
> > - err = rcar_gen4_add_dw_pcie_rp(rcar);
> > + mode = (enum dw_pcie_device_mode)of_device_get_match_data(&pdev->dev);
> > +
> > + if (mode == DW_PCIE_RC_TYPE)
> > + err = rcar_gen4_add_dw_pcie_rp(rcar);
> > + else if (mode == DW_PCIE_EP_TYPE)
> > + err = rcar_gen4_add_dw_pcie_ep(rcar);
> > +
>
> So now you have two places with the controller mode initialization:
> 1. rcar_gen4_pcie_of_match
> 2. rcar_gen4_add_dw_pcie_rp() and rcar_gen4_add_dw_pcie_ep()
> It looks a bit clumsy and less maintainable than could be. What I
> suggest is to create a new method which would do what is done above,
> but also would initialize the rcar_gen4_pcie->mode field:
>
> static int rcar_gen4_add_dw_pcie(struct rcar_gen4_pcie *rcar)
> {
> rcar->mode = device_get_match_data(&rcar->pdev->dev);
> switch (rcar->mode) {
> case DW_PCIE_RC_TYPE:
> return rcar_gen4_add_dw_pcie_rp(rcar);
> case DW_PCIE_EP_TYPE:
> return rcar_gen4_add_dw_pcie_ep(rcar);
> }
>
> return -EINVAL;
> }
Thank you for your suggestion. This code is better than my code.
> Of course the rcar_gen4_pcie->mode field initialization should be
> dropped from the rcar_gen4_add_dw_pcie_rp() and
> rcar_gen4_add_dw_pcie_ep() methods.
>
> and ...
>
> > if (err)
> > goto err_unprepare;
> >
> > @@ -356,12 +475,23 @@ static void rcar_gen4_pcie_remove(struct platform_device *pdev)
> > {
> > struct rcar_gen4_pcie *rcar = platform_get_drvdata(pdev);
> >
>
> > - rcar_gen4_remove_dw_pcie_rp(rcar);
> > + if (rcar->mode == DW_PCIE_RC_TYPE)
> > + rcar_gen4_remove_dw_pcie_rp(rcar);
> > + else if (rcar->mode == DW_PCIE_EP_TYPE)
> > + rcar_gen4_remove_dw_pcie_ep(rcar);
> > +
>
> ... similarly I would have added a respective antagonist:
>
> static void rcar_gen4_remove_dw_pcie(struct rcar_gen4_pcie *rcar)
> {
> switch (rcar->mode) {
> case DW_PCIE_RC_TYPE:
> rcar_gen4_remove_dw_pcie_rp(rcar);
> break;
> case DW_PCIE_EP_TYPE:
> rcar_gen4_remove_dw_pcie_ep(rcar);
> break;
> }
> }
>
> which would have been called from here instead of the open-coded
> switch-case statement. Thus the driver design will be preserved (a set
> of the init/deinit, add/remove, probe/remove and functional helper
> methods) and the mode initialization will be localized in a single
> place.
I understood it. I'll fix them on v23.
Best regards,
Yoshihiro Shimoda
> -Serge(y)
>
> > rcar_gen4_pcie_unprepare(rcar);
> > }
> >
> > static const struct of_device_id rcar_gen4_pcie_of_match[] = {
> > - { .compatible = "renesas,rcar-gen4-pcie", },
> > + {
> > + .compatible = "renesas,rcar-gen4-pcie",
> > + .data = (void *)DW_PCIE_RC_TYPE,
> > + },
> > + {
> > + .compatible = "renesas,rcar-gen4-pcie-ep",
> > + .data = (void *)DW_PCIE_EP_TYPE,
> > + },
> > {},
> > };
> > MODULE_DEVICE_TABLE(of, rcar_gen4_pcie_of_match);
> > --
> > 2.25.1
> >
