MIPS: SGI-IP27: abstract chipset irq from bridge

Bridge ASIC is widely used in different SGI systems, but the connected
chipset is either HUB, HEART or BEDROCK. This commit switches to
irq domain hierarchy for hub and bridge interrupts to get bridge
setup out of hub interrupt code.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
[paul.burton@mips.com:
  Resolve conflict with commit 69a07a4 ("MIPS: SGI-IP27: rework HUB
  interrupts").]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

arch/mips/Kconfig

@@ -675,6 +675,7 @@ config SGI_IP27
 	select SYS_HAS_EARLY_PRINTK
 	select HAVE_PCI
 	select IRQ_MIPS_CPU
+	select IRQ_DOMAIN_HIERARCHY
 	select NR_CPUS_DEFAULT_64
 	select PCI_DRIVERS_GENERIC
 	select PCI_XTALK_BRIDGE

arch/mips/include/asm/pci/bridge.h

@@ -805,6 +805,7 @@ struct bridge_controller {
 	struct bridge_regs	*base;
 	unsigned long		baddr;
 	unsigned long		intr_addr;
+	struct irq_domain	*domain;
 	unsigned int		pci_int[8];
 	nasid_t			nasid;
 };
@@ -819,6 +820,4 @@ struct bridge_controller {
 #define bridge_clr(bc, reg, val)	\
 	__raw_writel(__raw_readl(&bc->base->reg) & ~(val), &bc->base->reg)
 
-extern int request_bridge_irq(struct bridge_controller *bc, int pin);
-
 #endif /* _ASM_PCI_BRIDGE_H */

arch/mips/include/asm/sn/irq_alloc.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_SN_IRQ_ALLOC_H
+#define __ASM_SN_IRQ_ALLOC_H
+
+struct irq_alloc_info {
+	void *ctrl;
+	nasid_t nasid;
+	int pin;
+};
+
+#endif /* __ASM_SN_IRQ_ALLOC_H */

arch/mips/pci/pci-xtalk-bridge.c

@@ -14,7 +14,7 @@
 
 #include <asm/pci/bridge.h>
 #include <asm/paccess.h>
-#include <asm/sn/intr.h>
+#include <asm/sn/irq_alloc.h>
 
 /*
  * Most of the IOC3 PCI config register aren't present
@@ -310,6 +310,135 @@ static struct pci_ops bridge_pci_ops = {
 	.write	 = pci_write_config,
 };
 
+struct bridge_irq_chip_data {
+	struct bridge_controller *bc;
+	nasid_t nasid;
+};
+
+static int bridge_set_affinity(struct irq_data *d, const struct cpumask *mask,
+			       bool force)
+{
+#ifdef CONFIG_NUMA
+	struct bridge_irq_chip_data *data = d->chip_data;
+	int bit = d->parent_data->hwirq;
+	int pin = d->hwirq;
+	nasid_t nasid;
+	int ret, cpu;
+
+	ret = irq_chip_set_affinity_parent(d, mask, force);
+	if (ret >= 0) {
+		cpu = cpumask_first_and(mask, cpu_online_mask);
+		nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
+		bridge_write(data->bc, b_int_addr[pin].addr,
+			     (((data->bc->intr_addr >> 30) & 0x30000) |
+			      bit | (nasid << 8)));
+		bridge_read(data->bc, b_wid_tflush);
+	}
+	return ret;
+#else
+	return irq_chip_set_affinity_parent(d, mask, force);
+#endif
+}
+
+struct irq_chip bridge_irq_chip = {
+	.name             = "BRIDGE",
+	.irq_mask         = irq_chip_mask_parent,
+	.irq_unmask       = irq_chip_unmask_parent,
+	.irq_set_affinity = bridge_set_affinity
+};
+
+static int bridge_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			       unsigned int nr_irqs, void *arg)
+{
+	struct bridge_irq_chip_data *data;
+	struct irq_alloc_info *info = arg;
+	int ret;
+
+	if (nr_irqs > 1 || !info)
+		return -EINVAL;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
+	if (ret >= 0) {
+		data->bc = info->ctrl;
+		data->nasid = info->nasid;
+		irq_domain_set_info(domain, virq, info->pin, &bridge_irq_chip,
+				    data, handle_level_irq, NULL, NULL);
+	} else {
+		kfree(data);
+	}
+
+	return ret;
+}
+
+static void bridge_domain_free(struct irq_domain *domain, unsigned int virq,
+			       unsigned int nr_irqs)
+{
+	struct irq_data *irqd = irq_domain_get_irq_data(domain, virq);
+
+	if (nr_irqs)
+		return;
+
+	kfree(irqd->chip_data);
+	irq_domain_free_irqs_top(domain, virq, nr_irqs);
+}
+
+static int bridge_domain_activate(struct irq_domain *domain,
+				  struct irq_data *irqd, bool reserve)
+{
+	struct bridge_irq_chip_data *data = irqd->chip_data;
+	struct bridge_controller *bc = data->bc;
+	int bit = irqd->parent_data->hwirq;
+	int pin = irqd->hwirq;
+	u32 device;
+
+	bridge_write(bc, b_int_addr[pin].addr,
+		     (((bc->intr_addr >> 30) & 0x30000) |
+		      bit | (data->nasid << 8)));
+	bridge_set(bc, b_int_enable, (1 << pin));
+	bridge_set(bc, b_int_enable, 0x7ffffe00); /* more stuff in int_enable */
+
+	/*
+	 * Enable sending of an interrupt clear packt to the hub on a high to
+	 * low transition of the interrupt pin.
+	 *
+	 * IRIX sets additional bits in the address which are documented as
+	 * reserved in the bridge docs.
+	 */
+	bridge_set(bc, b_int_mode, (1UL << pin));
+
+	/*
+	 * We assume the bridge to have a 1:1 mapping between devices
+	 * (slots) and intr pins.
+	 */
+	device = bridge_read(bc, b_int_device);
+	device &= ~(7 << (pin*3));
+	device |= (pin << (pin*3));
+	bridge_write(bc, b_int_device, device);
+
+	bridge_read(bc, b_wid_tflush);
+	return 0;
+}
+
+static void bridge_domain_deactivate(struct irq_domain *domain,
+				     struct irq_data *irqd)
+{
+	struct bridge_irq_chip_data *data = irqd->chip_data;
+
+	bridge_clr(data->bc, b_int_enable, (1 << irqd->hwirq));
+	bridge_read(data->bc, b_wid_tflush);
+}
+
+static const struct irq_domain_ops bridge_domain_ops = {
+	.alloc      = bridge_domain_alloc,
+	.free       = bridge_domain_free,
+	.activate   = bridge_domain_activate,
+	.deactivate = bridge_domain_deactivate
+};
+
 /*
  * All observed requests have pin == 1. We could have a global here, that
  * gets incremented and returned every time - unfortunately, pci_map_irq
@@ -322,11 +451,16 @@ static struct pci_ops bridge_pci_ops = {
 static int bridge_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 {
 	struct bridge_controller *bc = BRIDGE_CONTROLLER(dev->bus);
+	struct irq_alloc_info info;
 	int irq;
 
 	irq = bc->pci_int[slot];
 	if (irq == -1) {
-		irq = request_bridge_irq(bc, slot);
+		info.ctrl = bc;
+		info.nasid = bc->nasid;
+		info.pin = slot;
+
+		irq = irq_domain_alloc_irqs(bc->domain, 1, bc->nasid, &info);
 		if (irq < 0)
 			return irq;
 
@@ -337,18 +471,34 @@ static int bridge_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 
 static int bridge_probe(struct platform_device *pdev)
 {
+	struct xtalk_bridge_platform_data *bd = dev_get_platdata(&pdev->dev);
 	struct device *dev = &pdev->dev;
 	struct bridge_controller *bc;
 	struct pci_host_bridge *host;
+	struct irq_domain *domain, *parent;
+	struct fwnode_handle *fn;
 	int slot;
 	int err;
-	struct xtalk_bridge_platform_data *bd = dev_get_platdata(&pdev->dev);
+
+	parent = irq_get_default_host();
+	if (!parent)
+		return -ENODEV;
+	fn = irq_domain_alloc_named_fwnode("BRIDGE");
+	if (!fn)
+		return -ENOMEM;
+	domain = irq_domain_create_hierarchy(parent, 0, 8, fn,
+					     &bridge_domain_ops, NULL);
+	irq_domain_free_fwnode(fn);
+	if (!domain)
+		return -ENOMEM;
 
 	pci_set_flags(PCI_PROBE_ONLY);
 
 	host = devm_pci_alloc_host_bridge(dev, sizeof(*bc));
-	if (!host)
-		return -ENOMEM;
+	if (!host) {
+		err = -ENOMEM;
+		goto err_remove_domain;
+	}
 
 	bc = pci_host_bridge_priv(host);
 
@@ -357,15 +507,15 @@ static int bridge_probe(struct platform_device *pdev)
 	bc->busn.end		= 0xff;
 	bc->busn.flags		= IORESOURCE_BUS;
 
+	bc->domain		= domain;
+
 	pci_add_resource_offset(&host->windows, &bd->mem, bd->mem_offset);
 	pci_add_resource_offset(&host->windows, &bd->io, bd->io_offset);
 	pci_add_resource(&host->windows, &bc->busn);
 
 	err = devm_request_pci_bus_resources(dev, &host->windows);
-	if (err < 0) {
-		pci_free_resource_list(&host->windows);
-		return err;
-	}
+	if (err < 0)
+		goto err_free_resource;
 
 	bc->nasid = bd->nasid;
 
@@ -419,20 +569,28 @@ static int bridge_probe(struct platform_device *pdev)
 
 	err = pci_scan_root_bus_bridge(host);
 	if (err < 0)
-		return err;
+		goto err_free_resource;
 
 	pci_bus_claim_resources(host->bus);
 	pci_bus_add_devices(host->bus);
 
 	platform_set_drvdata(pdev, host->bus);
 
 	return 0;
+
+err_free_resource:
+	pci_free_resource_list(&host->windows);
+err_remove_domain:
+	irq_domain_remove(domain);
+	return err;
 }
 
 static int bridge_remove(struct platform_device *pdev)
 {
 	struct pci_bus *bus = platform_get_drvdata(pdev);
+	struct bridge_controller *bc = BRIDGE_CONTROLLER(bus);
 
+	irq_domain_remove(bc->domain);
 	pci_lock_rescan_remove();
 	pci_stop_root_bus(bus);
 	pci_remove_root_bus(bus);