OpenRISC updates for 6.20

The main focus for this series has been to improve OpenRISC
 kernel out-of-the-box support for FPGA dev boards.
 
  - Adds device tree configurations for De0 Nano single and
    multicore configurations.
  - Fixes bug in OpenRISC SMP preventing the kernel from running on FPGA
    boards, due to IPIs not being unmasked on secondary CPUs in some
    configurations.
  - Picked up a fix from Brian Masney defining the nop() macro to fix
    build failures on OpenRISC for drivers using the nop() macro.
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Merge tag 'for-linus' of https://github.com/openrisc/linux

Pull OpenRISC updates from Stafford Horne:
 "The main focus for this series has been to improve OpenRISC kernel
  out-of-the-box support for FPGA dev boards.

   - Add device tree configurations for De0 Nano single and multicore
     configurations

   - Fix bug in OpenRISC SMP preventing the kernel from running on FPGA
     boards, due to IPIs not being unmasked on secondary CPUs in some
     configurations

   - Pick up a fix from Brian Masney defining the nop() macro to fix
     build failures on OpenRISC for drivers using it"

* tag 'for-linus' of https://github.com/openrisc/linux:
  openrisc: define arch-specific version of nop()
  openrisc: dts: Add de0 nano multicore config and devicetree
  openrisc: dts: Split simple smp dts to dts and dtsi
  openrisc: Fix IPIs on simple multicore systems
  openrisc: dts: Add de0 nano config and devicetree

arch/openrisc/boot/dts/de0-nano-common.dtsi

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
+
+/ {
+	leds0: leds {
+		compatible = "gpio-leds";
+
+		led-heartbeat {
+			gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_HEARTBEAT;
+			linux,default-trigger = "heartbeat";
+			label = "heartbeat";
+		};
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x00000000 0x02000000>;
+	};
+
+	/* 8 Green LEDs */
+	gpio0: gpio@91000000 {
+		compatible = "opencores,gpio";
+		reg = <0x91000000 0x1>, <0x91000001 0x1>;
+		reg-names = "dat", "dirout";
+		gpio-controller;
+		#gpio-cells = <2>;
+	};
+
+	/* 4 DIP Switches */
+	gpio1: gpio@92000000 {
+		compatible = "opencores,gpio";
+		reg = <0x92000000 0x1>, <0x92000001 0x1>;
+		reg-names = "dat", "dirout";
+		gpio-controller;
+		#gpio-cells = <2>;
+		status = "disabled";
+	};
+};

arch/openrisc/boot/dts/de0-nano-multicore.dts

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
+
+/dts-v1/;
+
+#include "simple-smp.dtsi"
+#include "de0-nano-common.dtsi"
+
+/ {
+	model = "Terasic DE0 Nano - Multicore";
+};
+
+&cpu0 {
+	clock-frequency = <50000000>;
+};
+
+&cpu1 {
+	clock-frequency = <50000000>;
+};
+
+&serial0 {
+	clock-frequency = <50000000>;
+};

arch/openrisc/boot/dts/de0-nano.dts

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/dts-v1/;
+
+#include "de0-nano-common.dtsi"
+
+/ {
+	model = "Terasic DE0 Nano";
+	compatible = "opencores,or1ksim";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	interrupt-parent = <&pic>;
+
+	aliases {
+		uart0 = &serial0;
+	};
+
+	chosen {
+		stdout-path = "uart0:115200";
+	};
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			compatible = "opencores,or1200-rtlsvn481";
+			reg = <0>;
+			clock-frequency = <50000000>;
+		};
+	};
+
+	/*
+	 * OR1K PIC is built into CPU and accessed via special purpose
+	 * registers.  It is not addressable and, hence, has no 'reg'
+	 * property.
+	 */
+	pic: pic {
+		compatible = "opencores,or1k-pic";
+		#interrupt-cells = <1>;
+		interrupt-controller;
+	};
+
+	serial0: serial@90000000 {
+		compatible = "opencores,uart16550-rtlsvn105", "ns16550a";
+		reg = <0x90000000 0x100>;
+		interrupts = <2>;
+		clock-frequency = <50000000>;
+	};
+};
+
+&gpio1 {
+	status = "okay";
+};

arch/openrisc/boot/dts/simple-smp.dts

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/dts-v1/;
+
+#include "simple-smp.dtsi"
+
+/ {
+	model = "Simple SMP Board";
+};
+
+&cpu0 {
+	clock-frequency = <20000000>;
+};
+
+&cpu1 {
+	clock-frequency = <20000000>;
+};
+
+&enet0 {
+	status = "okay";
+};
+
+&serial0 {
+	clock-frequency = <20000000>;
+};

arch/openrisc/boot/dts/simple-smp.dtsi

@@ -1,4 +1,3 @@
-/dts-v1/;
 / {
 	compatible = "opencores,or1ksim";
 	#address-cells = <1>;
@@ -22,15 +21,15 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		cpu@0 {
+
+		cpu0: cpu@0 {
 			compatible = "opencores,or1200-rtlsvn481";
 			reg = <0>;
-			clock-frequency = <20000000>;
 		};
-		cpu@1 {
+
+		cpu1: cpu@1 {
 			compatible = "opencores,or1200-rtlsvn481";
 			reg = <1>;
-			clock-frequency = <20000000>;
 		};
 	};
 
@@ -57,7 +56,6 @@
 		compatible = "opencores,uart16550-rtlsvn105", "ns16550a";
 		reg = <0x90000000 0x100>;
 		interrupts = <2>;
-		clock-frequency = <20000000>;
 	};
 
 	enet0: ethoc@92000000 {
@@ -65,5 +63,6 @@
 		reg = <0x92000000 0x800>;
 		interrupts = <4>;
 		big-endian;
+		status = "disabled";
 	};
 };

arch/openrisc/configs/de0_nano_defconfig

@@ -0,0 +1,79 @@
+CONFIG_SYSVIPC=y
+CONFIG_NO_HZ=y
+CONFIG_LOG_BUF_SHIFT=14
+CONFIG_BLK_DEV_INITRD=y
+# CONFIG_RD_GZIP is not set
+# CONFIG_RD_LZMA is not set
+# CONFIG_RD_LZO is not set
+# CONFIG_RD_LZ4 is not set
+# CONFIG_RD_ZSTD is not set
+CONFIG_EXPERT=y
+# CONFIG_EPOLL is not set
+# CONFIG_TIMERFD is not set
+# CONFIG_EVENTFD is not set
+# CONFIG_AIO is not set
+CONFIG_BUILTIN_DTB_NAME="de0-nano"
+# CONFIG_FPU is not set
+CONFIG_HZ_100=y
+# CONFIG_BLOCK is not set
+CONFIG_SLUB_TINY=y
+# CONFIG_COMPAT_BRK is not set
+# CONFIG_VM_EVENT_COUNTERS is not set
+CONFIG_NET=y
+CONFIG_UNIX=y
+CONFIG_UNIX_DIAG=y
+CONFIG_INET=y
+CONFIG_IP_MULTICAST=y
+CONFIG_INET_UDP_DIAG=y
+CONFIG_INET_RAW_DIAG=y
+CONFIG_INET_DIAG_DESTROY=y
+# CONFIG_IPV6 is not set
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+# CONFIG_PREVENT_FIRMWARE_BUILD is not set
+# CONFIG_FW_LOADER is not set
+# CONFIG_INPUT is not set
+# CONFIG_SERIO is not set
+# CONFIG_VT is not set
+# CONFIG_LEGACY_PTYS is not set
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
+# CONFIG_HW_RANDOM is not set
+CONFIG_PPS=y
+CONFIG_GPIO_SYSFS=y
+# CONFIG_GPIO_SYSFS_LEGACY is not set
+CONFIG_GPIO_GENERIC_PLATFORM=y
+# CONFIG_HWMON is not set
+# CONFIG_USB_SUPPORT is not set
+CONFIG_NEW_LEDS=y
+CONFIG_LEDS_CLASS=y
+CONFIG_LEDS_GPIO=y
+CONFIG_LEDS_TRIGGERS=y
+CONFIG_LEDS_TRIGGER_TIMER=y
+CONFIG_LEDS_TRIGGER_ONESHOT=y
+CONFIG_LEDS_TRIGGER_HEARTBEAT=y
+CONFIG_LEDS_TRIGGER_CPU=y
+CONFIG_LEDS_TRIGGER_ACTIVITY=y
+CONFIG_LEDS_TRIGGER_GPIO=y
+CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
+CONFIG_LEDS_TRIGGER_TRANSIENT=y
+CONFIG_LEDS_TRIGGER_PANIC=y
+CONFIG_LEDS_TRIGGER_NETDEV=y
+CONFIG_LEDS_TRIGGER_PATTERN=y
+CONFIG_LEDS_TRIGGER_TTY=y
+# CONFIG_VIRTIO_MENU is not set
+# CONFIG_VHOST_MENU is not set
+# CONFIG_DNOTIFY is not set
+CONFIG_TMPFS=y
+# CONFIG_XZ_DEC_X86 is not set
+# CONFIG_XZ_DEC_POWERPC is not set
+# CONFIG_XZ_DEC_ARM is not set
+# CONFIG_XZ_DEC_ARMTHUMB is not set
+# CONFIG_XZ_DEC_ARM64 is not set
+# CONFIG_XZ_DEC_SPARC is not set
+# CONFIG_XZ_DEC_RISCV is not set
+CONFIG_PRINTK_TIME=y
+# CONFIG_DEBUG_MISC is not set
+# CONFIG_FTRACE is not set
+# CONFIG_RUNTIME_TESTING_MENU is not set

arch/openrisc/configs/de0_nano_multicore_defconfig

@@ -0,0 +1,92 @@
+CONFIG_LOCALVERSION="-de0nano-smp"
+CONFIG_SYSVIPC=y
+CONFIG_POSIX_MQUEUE=y
+CONFIG_NO_HZ=y
+CONFIG_LOG_BUF_SHIFT=14
+CONFIG_BLK_DEV_INITRD=y
+# CONFIG_RD_GZIP is not set
+# CONFIG_RD_BZIP2 is not set
+# CONFIG_RD_LZMA is not set
+# CONFIG_RD_XZ is not set
+# CONFIG_RD_LZO is not set
+# CONFIG_RD_LZ4 is not set
+CONFIG_EXPERT=y
+# CONFIG_EPOLL is not set
+# CONFIG_TIMERFD is not set
+# CONFIG_EVENTFD is not set
+# CONFIG_AIO is not set
+CONFIG_KALLSYMS_ALL=y
+CONFIG_DCACHE_WRITETHROUGH=y
+CONFIG_BUILTIN_DTB_NAME="de0-nano-multicore"
+CONFIG_OPENRISC_HAVE_INST_CMOV=y
+CONFIG_SMP=y
+CONFIG_HZ_100=y
+CONFIG_JUMP_LABEL=y
+# CONFIG_BLOCK is not set
+CONFIG_SLUB_TINY=y
+# CONFIG_COMPAT_BRK is not set
+# CONFIG_VM_EVENT_COUNTERS is not set
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_UNIX_DIAG=y
+CONFIG_INET=y
+CONFIG_IP_MULTICAST=y
+CONFIG_TCP_CONG_ADVANCED=y
+# CONFIG_TCP_CONG_BIC is not set
+# CONFIG_TCP_CONG_CUBIC is not set
+# CONFIG_TCP_CONG_WESTWOOD is not set
+# CONFIG_TCP_CONG_HTCP is not set
+# CONFIG_IPV6 is not set
+# CONFIG_WIRELESS is not set
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+# CONFIG_PREVENT_FIRMWARE_BUILD is not set
+# CONFIG_FW_LOADER is not set
+CONFIG_NETDEVICES=y
+CONFIG_ETHOC=y
+CONFIG_MICREL_PHY=y
+# CONFIG_WLAN is not set
+# CONFIG_INPUT is not set
+# CONFIG_SERIO is not set
+# CONFIG_VT is not set
+# CONFIG_LEGACY_PTYS is not set
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
+# CONFIG_HW_RANDOM is not set
+CONFIG_GPIO_SYSFS=y
+# CONFIG_GPIO_CDEV_V1 is not set
+CONFIG_GPIO_GENERIC_PLATFORM=y
+# CONFIG_HWMON is not set
+# CONFIG_USB_SUPPORT is not set
+CONFIG_NEW_LEDS=y
+CONFIG_LEDS_CLASS=y
+CONFIG_LEDS_GPIO=y
+CONFIG_LEDS_TRIGGERS=y
+CONFIG_LEDS_TRIGGER_TIMER=y
+CONFIG_LEDS_TRIGGER_ONESHOT=y
+CONFIG_LEDS_TRIGGER_HEARTBEAT=y
+CONFIG_LEDS_TRIGGER_CPU=y
+CONFIG_LEDS_TRIGGER_ACTIVITY=y
+CONFIG_LEDS_TRIGGER_GPIO=y
+CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
+CONFIG_LEDS_TRIGGER_TRANSIENT=y
+CONFIG_LEDS_TRIGGER_PANIC=y
+CONFIG_LEDS_TRIGGER_NETDEV=y
+CONFIG_LEDS_TRIGGER_PATTERN=y
+CONFIG_LEDS_TRIGGER_TTY=y
+# CONFIG_DNOTIFY is not set
+CONFIG_TMPFS=y
+CONFIG_NFS_FS=y
+CONFIG_XZ_DEC=y
+CONFIG_PRINTK_TIME=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_GDB_SCRIPTS=y
+CONFIG_VMLINUX_MAP=y
+CONFIG_HARDLOCKUP_DETECTOR=y
+CONFIG_WQ_WATCHDOG=y
+CONFIG_WQ_CPU_INTENSIVE_REPORT=y
+CONFIG_STACKTRACE=y
+CONFIG_RCU_CPU_STALL_CPUTIME=y
+# CONFIG_RCU_TRACE is not set

arch/openrisc/configs/simple_smp_defconfig

@@ -20,7 +20,7 @@ CONFIG_SLUB=y
 CONFIG_SLUB_TINY=y
 CONFIG_MODULES=y
 # CONFIG_BLOCK is not set
-CONFIG_BUILTIN_DTB_NAME="simple_smp"
+CONFIG_BUILTIN_DTB_NAME="simple-smp"
 CONFIG_SMP=y
 CONFIG_HZ_100=y
 CONFIG_OPENRISC_HAVE_SHADOW_GPRS=y

arch/openrisc/include/asm/barrier.h

@@ -4,6 +4,8 @@
 
 #define mb() asm volatile ("l.msync" ::: "memory")
 
+#define nop() asm volatile ("l.nop")
+
 #include <asm-generic/barrier.h>
 
 #endif /* __ASM_BARRIER_H */

arch/openrisc/include/asm/smp.h

@@ -20,7 +20,8 @@ extern void smp_init_cpus(void);
 extern void arch_send_call_function_single_ipi(int cpu);
 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 
-extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
+extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int),
+			       unsigned int irq);
 extern void handle_IPI(unsigned int ipi_msg);
 
 #endif /* __ASM_OPENRISC_SMP_H */

arch/openrisc/kernel/smp.c

@@ -13,6 +13,7 @@
 
 #include <linux/smp.h>
 #include <linux/cpu.h>
+#include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
 #include <linux/irq.h>
@@ -25,6 +26,7 @@
 
 asmlinkage __init void secondary_start_kernel(void);
 
+static unsigned int ipi_irq __ro_after_init;
 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
 
 unsigned long secondary_release = -1;
@@ -39,6 +41,14 @@ enum ipi_msg_type {
 
 static DEFINE_SPINLOCK(boot_lock);
 
+static void or1k_ipi_enable(void)
+{
+	if (WARN_ON_ONCE(!ipi_irq))
+		return;
+
+	enable_percpu_irq(ipi_irq, 0);
+}
+
 static void boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	/*
@@ -136,6 +146,7 @@ asmlinkage __init void secondary_start_kernel(void)
 	complete(&cpu_running);
 
 	synchronise_count_slave(cpu);
+	or1k_ipi_enable();
 	set_cpu_online(cpu, true);
 
 	local_irq_enable();
@@ -195,9 +206,18 @@ void smp_send_stop(void)
 	smp_call_function(stop_this_cpu, NULL, 0);
 }
 
-void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
+void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int),
+			       unsigned int irq)
 {
+	if (WARN_ON(ipi_irq))
+		return;
+
 	smp_cross_call = fn;
+
+	ipi_irq = irq;
+
+	/* Enabled IPIs for boot CPU immediately */
+	or1k_ipi_enable();
 }
 
 void arch_send_call_function_single_ipi(int cpu)

drivers/irqchip/irq-ompic.c

@@ -84,6 +84,8 @@ DEFINE_PER_CPU(unsigned long, ops);
 
 static void __iomem *ompic_base;
 
+static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
+
 static inline u32 ompic_readreg(void __iomem *base, loff_t offset)
 {
 	return ioread32be(base + offset);
@@ -183,12 +185,17 @@ static int __init ompic_of_init(struct device_node *node,
 		goto out_unmap;
 	}
 
-	ret = request_irq(irq, ompic_ipi_handler, IRQF_PERCPU,
-				"ompic_ipi", NULL);
-	if (ret)
-		goto out_irq_disp;
+	irq_set_percpu_devid(irq);
+	ret = request_percpu_irq(irq, ompic_ipi_handler, "ompic_ipi",
+				 &ipi_dummy_dev);
 
-	set_smp_cross_call(ompic_raise_softirq);
+	if (ret) {
+		pr_err("ompic: failed to request irq %d, error: %d",
+		       irq, ret);
+		goto out_irq_disp;
+	}
+
+	set_smp_cross_call(ompic_raise_softirq, irq);
 
 	return 0;
 

drivers/irqchip/irq-or1k-pic.c

@@ -118,11 +118,36 @@ static void or1k_pic_handle_irq(struct pt_regs *regs)
 		generic_handle_domain_irq(root_domain, irq);
 }
 
+/*
+ * The OR1K PIC is a cpu-local interrupt controller and does not distinguish or
+ * use distinct irq number ranges for per-cpu event interrupts (IPI). Since
+ * information to determine whether a particular irq number should be treated as
+ * per-cpu is not available at mapping time, we use a wrapper handler function
+ * which chooses the right handler at runtime based on whether IRQF_PERCPU was
+ * used when requesting the irq.  Borrowed from J-Core AIC.
+ */
+static void or1k_irq_flow_handler(struct irq_desc *desc)
+{
+#ifdef CONFIG_SMP
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	struct or1k_pic_dev *pic = data->domain->host_data;
+
+	if (irqd_is_per_cpu(data))
+		handle_percpu_devid_irq(desc);
+	else
+		pic->handle(desc);
+#endif
+}
+
 static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
 {
 	struct or1k_pic_dev *pic = d->host_data;
 
-	irq_set_chip_and_handler(irq, &pic->chip, pic->handle);
+	if (IS_ENABLED(CONFIG_SMP))
+		irq_set_chip_and_handler(irq, &pic->chip, or1k_irq_flow_handler);
+	else
+		irq_set_chip_and_handler(irq, &pic->chip, pic->handle);
+
 	irq_set_status_flags(irq, pic->flags);
 
 	return 0;