[ARM] Support FPGA, fixed IRQ mapping

arch/arm/boot/dts/xilinx/ni-zynq.dtsi

@@ -105,6 +105,11 @@
 			clock-frequency = <58824000>;
 		};
 
+		fpgaperipheral@f8007000 {
+			compatible = "fpgaperipheral";
+			reg = <0xf8007000 0x100>;
+		};
+
 		i2c2: i2c@81000000 {
 			compatible = "xlnx,xps-iic-2.00.a";
 			status = "disabled";
@@ -173,6 +178,14 @@
 	arm,standby-mode = <0>;
 };
 
+&devcfg {
+	status = "disabled";
+};
+
+&fpga_full {
+	status = "disabled";
+};
+
 /*
  * The CoreSight debug/trace macrocells are not accessible on NI Zynq-based
  * targets: reading their AMBA peripheral-ID registers (done unconditionally

arch/arm/configs/nati_zynq_defconfig

@@ -23,6 +23,7 @@ CONFIG_EXPERT=y
 CONFIG_PERF_EVENTS=y
 CONFIG_ARCH_VEXPRESS=y
 CONFIG_ARCH_ZYNQ=y
+CONFIG_NI_ZYNQ_GIC_LEGACY_IRQDOMAIN=y
 CONFIG_ARM_ERRATA_754322=y
 CONFIG_ARM_ERRATA_764369=y
 CONFIG_ARM_ERRATA_775420=y

arch/arm/mach-zynq/Kconfig

@@ -15,3 +15,13 @@ config ARCH_ZYNQ
 	select SOC_BUS
 	help
 	  Support for Xilinx Zynq ARM Cortex A9 Platform
+
+config NI_ZYNQ_GIC_LEGACY_IRQDOMAIN
+	bool "Use fixed GIC IRQ numbers on NI Zynq targets"
+	depends on ARCH_ZYNQ
+	help
+	  Create fixed Linux IRQ mappings for the primary GIC so that its
+	  Linux IRQ numbers equal the corresponding GIC hardware IRQ numbers.
+	  This preserves compatibility with NI drivers that use fixed IRQs.
+	  Enable this only on NI Zynq systems that require the legacy IRQ
+	  numbering contract.

drivers/irqchip/irq-gic.c

@@ -1160,6 +1160,73 @@ static const struct irq_domain_ops gic_irq_domain_hierarchy_ops = {
 	.free = irq_domain_free_irqs_top,
 };
 
+static const struct irq_domain_ops gic_irq_domain_legacy_ops = {
+	.map = gic_irq_domain_map,
+	.translate = gic_irq_domain_translate,
+	.alloc = gic_irq_domain_alloc,
+	.free = irq_domain_free_irqs_top,
+};
+
+static struct irq_domain *gic_create_irq_domain(struct gic_chip_data *gic,
+						struct fwnode_handle *handle,
+						unsigned int gic_irqs)
+{
+	struct irq_domain *domain;
+	unsigned int irq_count;
+	unsigned int irq;
+	int irq_base;
+
+	if (!IS_ENABLED(CONFIG_NI_ZYNQ_GIC_LEGACY_IRQDOMAIN) ||
+	    gic != &gic_data[0])
+		return irq_domain_create_linear(handle, gic_irqs,
+						&gic_irq_domain_hierarchy_ops,
+						gic);
+
+	if (gic_irqs <= NR_IRQS_LEGACY)
+		return NULL;
+
+	irq_count = gic_irqs - NR_IRQS_LEGACY;
+	irq_base = irq_alloc_descs(NR_IRQS_LEGACY, NR_IRQS_LEGACY,
+				   irq_count, numa_node_id());
+	if (irq_base != NR_IRQS_LEGACY) {
+		if (irq_base >= 0)
+			irq_free_descs(irq_base, irq_count);
+		pr_err("GIC: cannot reserve fixed IRQ range %u-%u (%d)\n",
+		       NR_IRQS_LEGACY, gic_irqs - 1, irq_base);
+		return NULL;
+	}
+
+	domain = irq_domain_create_legacy(handle, irq_count, NR_IRQS_LEGACY,
+					  NR_IRQS_LEGACY,
+					  &gic_irq_domain_legacy_ops, gic);
+	if (!domain) {
+		irq_free_descs(irq_base, irq_count);
+		return NULL;
+	}
+
+	for (irq = NR_IRQS_LEGACY; irq < gic_irqs; irq++) {
+		if (irq_find_mapping(domain, irq) != irq) {
+			unsigned int mapped_irq;
+
+			pr_err("GIC: failed to establish fixed mapping for IRQ%u\n",
+			       irq);
+			for (mapped_irq = NR_IRQS_LEGACY;
+			     mapped_irq < gic_irqs; mapped_irq++) {
+				if (irq_find_mapping(domain, mapped_irq) == mapped_irq)
+					irq_dispose_mapping(mapped_irq);
+				else
+					irq_free_desc(mapped_irq);
+			}
+			irq_domain_remove(domain);
+			return NULL;
+		}
+	}
+
+	pr_info("GIC: using fixed Linux IRQ mapping %u-%u\n",
+		NR_IRQS_LEGACY, gic_irqs - 1);
+	return domain;
+}
+
 static int gic_init_bases(struct gic_chip_data *gic,
 			  struct fwnode_handle *handle)
 {
@@ -1207,9 +1274,7 @@ static int gic_init_bases(struct gic_chip_data *gic,
 		gic_irqs = 1020;
 	gic->gic_irqs = gic_irqs;
 
-	gic->domain = irq_domain_create_linear(handle, gic_irqs,
-					       &gic_irq_domain_hierarchy_ops,
-					       gic);
+	gic->domain = gic_create_irq_domain(gic, handle, gic_irqs);
 	if (WARN_ON(!gic->domain)) {
 		ret = -ENODEV;
 		goto error;

drivers/net/ethernet/cadence/macb_main.c

@@ -4487,7 +4487,6 @@ static const struct net_device_ops macb_netdev_ops = {
 static int macb_fpga_notifier(struct notifier_block *nb, unsigned long val, void *data)
 {
 	struct macb *bp = container_of(nb, struct macb, fpga_notifier);
-	struct net_device *dev = bp->dev;
 
 	switch (val) {
 	case FPGA_PERIPHERAL_DOWN:
@@ -4501,9 +4500,6 @@ static int macb_fpga_notifier(struct notifier_block *nb, unsigned long val, void
 			if (netif_running(bp->dev)) {
 				dev_deactivate(bp->dev);
 				macb_close(bp->dev);
-				if (phy_interrupt_is_valid(dev->phydev))
-					phy_free_interrupt(dev->phydev);
-				phy_stop_machine_nolink(dev->phydev);
 			}
 
 			bp->fpga_down = 1;
@@ -4524,9 +4520,6 @@ static int macb_fpga_notifier(struct notifier_block *nb, unsigned long val, void
 
 		/* If the interface has been opened. */
 		if (netif_running(bp->dev)) {
-			phy_start_machine(dev->phydev);
-			if (phy_interrupt_is_valid(dev->phydev))
-				phy_request_interrupt(dev->phydev);
 			macb_open(bp->dev);
 			dev_activate(bp->dev);
 		}

drivers/tty/serial/8250/8250_ni.c

@@ -18,12 +18,17 @@
 #include <linux/init.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/serial_core.h>
 #include <linux/types.h>
 
+#ifdef CONFIG_FPGA_PERIPHERAL
+#include <misc/fpgaperipheral.h>
+#endif
+
 #include "8250.h"
 
 /* Extra bits in UART_ACR */
@@ -77,8 +82,58 @@ struct ni16550_device_info {
 struct ni16550_data {
 	int line;
 	struct clk *clk;
+#ifdef CONFIG_FPGA_PERIPHERAL
+	struct notifier_block fpga_notifier;
+	bool fpga_notifier_registered;
+	bool fpga_suspended;
+#endif
 };
 
+#ifdef CONFIG_FPGA_PERIPHERAL
+static u32 ni16550_disabled_serial_in(struct uart_port *port,
+				      unsigned int offset)
+{
+	return 0;
+}
+
+static void ni16550_disabled_serial_out(struct uart_port *port,
+					unsigned int offset, u32 value)
+{
+}
+
+static int ni16550_fpga_notify(struct notifier_block *nb,
+			      unsigned long event, void *unused)
+{
+	struct ni16550_data *data = container_of(nb, struct ni16550_data,
+						 fpga_notifier);
+	struct uart_8250_port *uart = serial8250_get_port(data->line);
+
+	switch (event) {
+	case FPGA_PERIPHERAL_DOWN:
+		if (!data->fpga_suspended) {
+			serial8250_suspend_port(data->line);
+			uart->port.serial_in = ni16550_disabled_serial_in;
+			uart->port.serial_out = ni16550_disabled_serial_out;
+			data->fpga_suspended = true;
+		}
+		break;
+	case FPGA_PERIPHERAL_UP:
+		if (data->fpga_suspended) {
+			serial8250_set_defaults(uart);
+			serial8250_resume_port(data->line);
+			data->fpga_suspended = false;
+		}
+		break;
+	case FPGA_PERIPHERAL_FAILED:
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+#endif
+
 static int ni16550_enable_transceivers(struct uart_port *port)
 {
 	u8 pcr;
@@ -405,6 +460,20 @@ static int ni16550_probe(struct platform_device *pdev)
 		return ret;
 	data->line = ret;
 
+#ifdef CONFIG_FPGA_PERIPHERAL
+	if (dev_of_node(dev)) {
+		data->fpga_notifier.notifier_call = ni16550_fpga_notify;
+		ret = blocking_notifier_chain_register(&fpgaperipheral_notifier_list,
+						       &data->fpga_notifier);
+		if (ret) {
+			serial8250_unregister_port(data->line);
+			return dev_err_probe(dev, ret,
+					     "failed to register FPGA notifier\n");
+		}
+		data->fpga_notifier_registered = true;
+	}
+#endif
+
 	platform_set_drvdata(pdev, data);
 	return 0;
 }
@@ -413,6 +482,11 @@ static void ni16550_remove(struct platform_device *pdev)
 {
 	struct ni16550_data *data = platform_get_drvdata(pdev);
 
+#ifdef CONFIG_FPGA_PERIPHERAL
+	if (data->fpga_notifier_registered)
+		blocking_notifier_chain_unregister(&fpgaperipheral_notifier_list,
+							 &data->fpga_notifier);
+#endif
 	serial8250_unregister_port(data->line);
 }