Subject: Re: [PATCH v2 09/16] PCI: dwc: Rework MSI initialization

From: Jisheng Zhang <[email-masked]>
Date: Mon, 9 Nov 2020 10:53:25 +0800

On Thu,  5 Nov 2020 15:11:52 -0600
Rob Herring <[email-masked]> wrote:

> CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe.
> 
> 
> There are 3 possible MSI implementations for the DWC host. The first is
> using the built-in DWC MSI controller. The 2nd is a custom MSI
> controller as part of the PCI host (keystone only). The 3rd is an
> external MSI controller (typically GICv3 ITS). Currently, the last 2
> are distinguished with a .msi_host_init() hook with the 3rd option using
> an empty function. However we can detect the 3rd case with the presence
> of 'msi-parent' or 'msi-map' properties, so let's do that instead and
> remove the empty functions.
> 
> Cc: Murali Karicheri <[email-masked]>
> Cc: Lorenzo Pieralisi <[email-masked]>
> Cc: Bjorn Helgaas <[email-masked]>
> Cc: Minghuan Lian <[email-masked]>
> Cc: Mingkai Hu <[email-masked]>
> Cc: Roy Zang <[email-masked]>
> Cc: Gustavo Pimentel <[email-masked]>
> Cc: [email-masked]
> Acked-by: Jingoo Han <[email-masked]>
> Signed-off-by: Rob Herring <[email-masked]>
> ---
>  drivers/pci/controller/dwc/pci-keystone.c     |  9 -------
>  drivers/pci/controller/dwc/pci-layerscape.c   | 25 -------------------
>  .../pci/controller/dwc/pcie-designware-host.c | 20 +++++++++------
>  drivers/pci/controller/dwc/pcie-designware.h  |  1 +
>  drivers/pci/controller/dwc/pcie-intel-gw.c    |  9 -------
>  5 files changed, 13 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
> index 9cf14f13798b..784385ae6074 100644
> --- a/drivers/pci/controller/dwc/pci-keystone.c
> +++ b/drivers/pci/controller/dwc/pci-keystone.c
> @@ -272,14 +272,6 @@ static void ks_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie,
>         ks_pcie_app_writel(ks_pcie, IRQ_EOI, offset);
>  }
> 
> -/*
> - * Dummy function so that DW core doesn't configure MSI
> - */
> -static int ks_pcie_am654_msi_host_init(struct pcie_port *pp)
> -{
> -       return 0;
> -}
> -
>  static void ks_pcie_enable_error_irq(struct keystone_pcie *ks_pcie)
>  {
>         ks_pcie_app_writel(ks_pcie, ERR_IRQ_ENABLE_SET, ERR_IRQ_ALL);
> @@ -854,7 +846,6 @@ static const struct dw_pcie_host_ops ks_pcie_host_ops = {
> 
>  static const struct dw_pcie_host_ops ks_pcie_am654_host_ops = {
>         .host_init = ks_pcie_host_init,
> -       .msi_host_init = ks_pcie_am654_msi_host_init,
>  };
> 
>  static irqreturn_t ks_pcie_err_irq_handler(int irq, void *priv)
> diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
> index 53e56d54c482..0d84986c4c16 100644
> --- a/drivers/pci/controller/dwc/pci-layerscape.c
> +++ b/drivers/pci/controller/dwc/pci-layerscape.c
> @@ -168,37 +168,12 @@ static int ls1021_pcie_host_init(struct pcie_port *pp)
>         return ls_pcie_host_init(pp);
>  }
> 
> -static int ls_pcie_msi_host_init(struct pcie_port *pp)
> -{
> -       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> -       struct device *dev = pci->dev;
> -       struct device_node *np = dev->of_node;
> -       struct device_node *msi_node;
> -
> -       /*
> -        * The MSI domain is set by the generic of_msi_configure().  This
> -        * .msi_host_init() function keeps us from doing the default MSI
> -        * domain setup in dw_pcie_host_init() and also enforces the
> -        * requirement that "msi-parent" exists.
> -        */
> -       msi_node = of_parse_phandle(np, "msi-parent", 0);
> -       if (!msi_node) {
> -               dev_err(dev, "failed to find msi-parent\n");
> -               return -EINVAL;
> -       }
> -
> -       of_node_put(msi_node);
> -       return 0;
> -}
> -
>  static const struct dw_pcie_host_ops ls1021_pcie_host_ops = {
>         .host_init = ls1021_pcie_host_init,
> -       .msi_host_init = ls_pcie_msi_host_init,
>  };
> 
>  static const struct dw_pcie_host_ops ls_pcie_host_ops = {
>         .host_init = ls_pcie_host_init,
> -       .msi_host_init = ls_pcie_msi_host_init,
>  };
> 
>  static const struct dw_pcie_ops dw_ls1021_pcie_ops = {
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 95deef0eaadf..9b952639d020 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -365,6 +365,10 @@ int dw_pcie_host_init(struct pcie_port *pp)
>                 pci->link_gen = of_pci_get_max_link_speed(np);
> 
>         if (pci_msi_enabled()) {
> +               pp->has_msi_ctrl = !(pp->ops->msi_host_init ||
> +                                    of_property_read_bool(np, "msi-parent") ||
> +                                    of_property_read_bool(np, "msi-map"));
> +
>                 if (!pp->num_vectors) {
>                         pp->num_vectors = MSI_DEF_NUM_VECTORS;
>                 } else if (pp->num_vectors > MAX_MSI_IRQS) {
> @@ -372,7 +376,11 @@ int dw_pcie_host_init(struct pcie_port *pp)
>                         return -EINVAL;
>                 }
> 
> -               if (!pp->ops->msi_host_init) {
> +               if (pp->ops->msi_host_init) {
> +                       ret = pp->ops->msi_host_init(pp);
> +                       if (ret < 0)
> +                               return ret;
> +               } else if (pp->has_msi_ctrl) {
>                         if (!pp->msi_irq) {
>                                 pp->msi_irq = platform_get_irq_byname_optional(pdev, "msi");
>                                 if (pp->msi_irq < 0) {
> @@ -402,10 +410,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
>                                 pp->msi_data = 0;
>                                 goto err_free_msi;
>                         }
> -               } else {
> -                       ret = pp->ops->msi_host_init(pp);
> -                       if (ret < 0)
> -                               return ret;
>                 }
>         }
> 
> @@ -426,7 +430,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
>                 return 0;
> 
>  err_free_msi:
> -       if (pci_msi_enabled() && !pp->ops->msi_host_init)
> +       if (pp->has_msi_ctrl)
>                 dw_pcie_free_msi(pp);
>         return ret;
>  }
> @@ -436,7 +440,7 @@ void dw_pcie_host_deinit(struct pcie_port *pp)
>  {
>         pci_stop_root_bus(pp->bridge->bus);
>         pci_remove_root_bus(pp->bridge->bus);
> -       if (pci_msi_enabled() && !pp->ops->msi_host_init)
> +       if (pp->has_msi_ctrl)
>                 dw_pcie_free_msi(pp);
>  }
>  EXPORT_SYMBOL_GPL(dw_pcie_host_deinit);
> @@ -544,7 +548,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> 
>         dw_pcie_setup(pci);
> 
> -       if (pci_msi_enabled() && !pp->ops->msi_host_init) {
> +       if (pp->has_msi_ctrl) {
>                 num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> 
>                 /* Initialize IRQ Status array */
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 96382dcb2859..5d374bab10d1 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -175,6 +175,7 @@ struct dw_pcie_host_ops {
>  };
> 
>  struct pcie_port {
> +       bool                    has_msi_ctrl:1;

Can we relocate has_msi_ctrl? e.g put it at the end of the pcie_port structure.

Thanks

>         u64                     cfg0_base;
>         void __iomem            *va_cfg0_base;
>         u32                     cfg0_size;
> diff --git a/drivers/pci/controller/dwc/pcie-intel-gw.c b/drivers/pci/controller/dwc/pcie-intel-gw.c
> index c562eb7454b1..292b9de86532 100644
> --- a/drivers/pci/controller/dwc/pcie-intel-gw.c
> +++ b/drivers/pci/controller/dwc/pcie-intel-gw.c
> @@ -385,14 +385,6 @@ static int intel_pcie_rc_init(struct pcie_port *pp)
>         return intel_pcie_host_setup(lpp);
>  }
> 
> -/*
> - * Dummy function so that DW core doesn't configure MSI
> - */
> -static int intel_pcie_msi_init(struct pcie_port *pp)
> -{
> -       return 0;
> -}
> -
>  static u64 intel_pcie_cpu_addr(struct dw_pcie *pcie, u64 cpu_addr)
>  {
>         return cpu_addr + BUS_IATU_OFFSET;
> @@ -404,7 +396,6 @@ static const struct dw_pcie_ops intel_pcie_ops = {
> 
>  static const struct dw_pcie_host_ops intel_pcie_dw_ops = {
>         .host_init =            intel_pcie_rc_init,
> -       .msi_host_init =        intel_pcie_msi_init,
>  };
> 
>  static const struct intel_pcie_soc pcie_data = {
> --
> 2.25.1
> 
> 
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