PCI: apple: Convert to MSI parent infrastructure

In an effort to move ARM64 away from the legacy MSI setup, convert the
Apple PCIe driver to the MSI-parent infrastructure and let each device have
its own MSI domain.

[ tglx: Moved the struct out of the function call argument ]

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Link: https://lore.kernel.org/all/20250513172819.2216709-8-maz@kernel.org

Author: Marc Zyngier

drivers/pci/controller/Kconfig

@@ -40,6 +40,7 @@ config PCIE_APPLE
 	depends on OF
 	depends on PCI_MSI
 	select PCI_HOST_COMMON
+	select IRQ_MSI_LIB
 	help
 	  Say Y here if you want to enable PCIe controller support on Apple
 	  system-on-chips, like the Apple M1. This is required for the USB

drivers/pci/controller/pcie-apple.c

@@ -22,6 +22,7 @@
 #include <linux/kernel.h>
 #include <linux/iopoll.h>
 #include <linux/irqchip/chained_irq.h>
+#include <linux/irqchip/irq-msi-lib.h>
 #include <linux/irqdomain.h>
 #include <linux/list.h>
 #include <linux/module.h>
@@ -133,7 +134,6 @@ struct apple_pcie {
 	struct mutex		lock;
 	struct device		*dev;
 	void __iomem            *base;
-	struct irq_domain	*domain;
 	unsigned long		*bitmap;
 	struct list_head	ports;
 	struct completion	event;
@@ -162,27 +162,6 @@ static void rmw_clear(u32 clr, void __iomem *addr)
 	writel_relaxed(readl_relaxed(addr) & ~clr, addr);
 }
 
-static void apple_msi_top_irq_mask(struct irq_data *d)
-{
-	pci_msi_mask_irq(d);
-	irq_chip_mask_parent(d);
-}
-
-static void apple_msi_top_irq_unmask(struct irq_data *d)
-{
-	pci_msi_unmask_irq(d);
-	irq_chip_unmask_parent(d);
-}
-
-static struct irq_chip apple_msi_top_chip = {
-	.name			= "PCIe MSI",
-	.irq_mask		= apple_msi_top_irq_mask,
-	.irq_unmask		= apple_msi_top_irq_unmask,
-	.irq_eoi		= irq_chip_eoi_parent,
-	.irq_set_affinity	= irq_chip_set_affinity_parent,
-	.irq_set_type		= irq_chip_set_type_parent,
-};
-
 static void apple_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
 {
 	msg->address_hi = upper_32_bits(DOORBELL_ADDR);
@@ -226,8 +205,7 @@ static int apple_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 
 	for (i = 0; i < nr_irqs; i++) {
 		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
-					      &apple_msi_bottom_chip,
-					      domain->host_data);
+					      &apple_msi_bottom_chip, pcie);
 	}
 
 	return 0;
@@ -251,12 +229,6 @@ static const struct irq_domain_ops apple_msi_domain_ops = {
 	.free	= apple_msi_domain_free,
 };
 
-static struct msi_domain_info apple_msi_info = {
-	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
-		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
-	.chip	= &apple_msi_top_chip,
-};
-
 static void apple_port_irq_mask(struct irq_data *data)
 {
 	struct apple_pcie_port *port = irq_data_get_irq_chip_data(data);
@@ -595,11 +567,28 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	return 0;
 }
 
+static const struct msi_parent_ops apple_msi_parent_ops = {
+	.supported_flags	= (MSI_GENERIC_FLAGS_MASK	|
+				   MSI_FLAG_PCI_MSIX		|
+				   MSI_FLAG_MULTI_PCI_MSI),
+	.required_flags		= (MSI_FLAG_USE_DEF_DOM_OPS	|
+				   MSI_FLAG_USE_DEF_CHIP_OPS	|
+				   MSI_FLAG_PCI_MSI_MASK_PARENT),
+	.chip_flags		= MSI_CHIP_FLAG_SET_EOI,
+	.bus_select_token	= DOMAIN_BUS_PCI_MSI,
+	.init_dev_msi_info	= msi_lib_init_dev_msi_info,
+};
+
 static int apple_msi_init(struct apple_pcie *pcie)
 {
 	struct fwnode_handle *fwnode = dev_fwnode(pcie->dev);
+	struct irq_domain_info info = {
+		.fwnode		= fwnode,
+		.ops		= &apple_msi_domain_ops,
+		.size		= pcie->nvecs,
+		.host_data	= pcie,
+	};
 	struct of_phandle_args args = {};
-	struct irq_domain *parent;
 	int ret;
 
 	ret = of_parse_phandle_with_args(to_of_node(fwnode), "msi-ranges",
@@ -619,28 +608,16 @@ static int apple_msi_init(struct apple_pcie *pcie)
 	if (!pcie->bitmap)
 		return -ENOMEM;
 
-	parent = irq_find_matching_fwspec(&pcie->fwspec, DOMAIN_BUS_WIRED);
-	if (!parent) {
+	info.parent = irq_find_matching_fwspec(&pcie->fwspec, DOMAIN_BUS_WIRED);
+	if (!info.parent) {
 		dev_err(pcie->dev, "failed to find parent domain\n");
 		return -ENXIO;
 	}
 
-	parent = irq_domain_create_hierarchy(parent, 0, pcie->nvecs, fwnode,
-					     &apple_msi_domain_ops, pcie);
-	if (!parent) {
+	if (!msi_create_parent_irq_domain(&info, &apple_msi_parent_ops)) {
 		dev_err(pcie->dev, "failed to create IRQ domain\n");
 		return -ENOMEM;
 	}
-	irq_domain_update_bus_token(parent, DOMAIN_BUS_NEXUS);
-
-	pcie->domain = pci_msi_create_irq_domain(fwnode, &apple_msi_info,
-						 parent);
-	if (!pcie->domain) {
-		dev_err(pcie->dev, "failed to create MSI domain\n");
-		irq_domain_remove(parent);
-		return -ENOMEM;
-	}
-
 	return 0;
 }