PCI: dwc: Rework MSI initialization

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.

Link: https://lore.kernel.org/r/20201105211159.1814485-10-robh@kernel.org
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Minghuan Lian <minghuan.Lian@nxp.com>
Cc: Mingkai Hu <mingkai.hu@nxp.com>
Cc: Roy Zang <roy.zang@nxp.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: linuxppc-dev@lists.ozlabs.org

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)

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 = {

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -365,14 +365,22 @@ 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) {
  dev_err(dev, "Invalid number of vectors\n");
  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 */

drivers/pci/controller/dwc/pcie-designware.h

@@ -176,6 +176,7 @@ struct dw_pcie_host_ops {
 };
 
 struct pcie_port {
+ bool has_msi_ctrl:1;
  u64 cfg0_base;
  void __iomem *va_cfg0_base;
  u32 cfg0_size;

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 = {