diff mbox series

[RFC,v1,05/10] irqchip: Add ACLINT software interrupt driver

Message ID 20210612160422.330705-6-anup.patel@wdc.com (mailing list archive)
State New, archived
Headers show
Series RISC-V ACLINT Support | expand

Commit Message

Anup Patel June 12, 2021, 4:04 p.m. UTC 
The RISC-V ACLINT provides MSWI and SSWI devices for M-mode and
S-mode software interrupts respectively. We add irqchip driver
which provide IPI operations based on ACLINT [M|S]SWI devices
to the Linux RISC-V kernel.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 drivers/irqchip/Kconfig          |  11 +++
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-aclint-swi.c | 122 +++++++++++++++++++++++++++++++
 3 files changed, 134 insertions(+)
 create mode 100644 drivers/irqchip/irq-aclint-swi.c

Comments

Marc Zyngier June 13, 2021, 9:41 a.m. UTC | #1 
On Sat, 12 Jun 2021 17:04:17 +0100,
Anup Patel <anup.patel@wdc.com> wrote:
> 
> The RISC-V ACLINT provides MSWI and SSWI devices for M-mode and
> S-mode software interrupts respectively. We add irqchip driver
> which provide IPI operations based on ACLINT [M|S]SWI devices
> to the Linux RISC-V kernel.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
>  drivers/irqchip/Kconfig          |  11 +++
>  drivers/irqchip/Makefile         |   1 +
>  drivers/irqchip/irq-aclint-swi.c | 122 +++++++++++++++++++++++++++++++
>  3 files changed, 134 insertions(+)
>  create mode 100644 drivers/irqchip/irq-aclint-swi.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 62543a4eccc0..2010d493b03b 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -508,6 +508,17 @@ config RISCV_INTC
>  
>  	   If you don't know what to do here, say Y.
>  
> +config RISCV_ACLINT_SWI
> +	bool "RISC-V Advanced Core Local Interruptor Software Interrupts"
> +	depends on RISCV
> +	help
> +	   This enables support for software interrupts using the Advanced
> +	   Core Local Interruptor (ACLINT) found in RISC-V systems.  The
> +	   RISC-V ACLINT provides devices for inter-process interrupt and
> +	   timer functionality.
> +
> +	   If you don't know what to do here, say Y.
> +
>  config SIFIVE_PLIC
>  	bool "SiFive Platform-Level Interrupt Controller"
>  	depends on RISCV
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index f88cbf36a9d2..a6edf6733c1d 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -97,6 +97,7 @@ obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
>  obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
>  obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
>  obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
> +obj-$(CONFIG_RISCV_ACLINT_SWI)		+= irq-aclint-swi.o
>  obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
>  obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
>  obj-$(CONFIG_IMX_INTMUX)		+= irq-imx-intmux.o
> diff --git a/drivers/irqchip/irq-aclint-swi.c b/drivers/irqchip/irq-aclint-swi.c
> new file mode 100644
> index 000000000000..f9607072cc7b
> --- /dev/null
> +++ b/drivers/irqchip/irq-aclint-swi.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + */
> +
> +#define pr_fmt(fmt) "aclint-swi: " fmt
> +#include <linux/cpu.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/smp.h>
> +
> +struct aclint_swi {
> +	void __iomem *sip_reg;
> +};
> +static DEFINE_PER_CPU(struct aclint_swi, aclint_swis);
> +
> +static void aclint_swi_send_ipi(const struct cpumask *target)
> +{
> +	unsigned int cpu;
> +	struct aclint_swi *swi;
> +
> +	for_each_cpu(cpu, target) {
> +		swi = per_cpu_ptr(&aclint_swis, cpu);
> +		if (!swi->sip_reg) {
> +			pr_warn("%s: CPU%d SIP register not available\n",
> +				__func__, cpu);
> +			continue;
> +		}
> +
> +		writel(1, swi->sip_reg);
> +	}
> +}
> +
> +static void aclint_swi_clear_ipi(void)
> +{
> +	struct aclint_swi *swi = this_cpu_ptr(&aclint_swis);
> +
> +	if (!swi->sip_reg) {
> +		pr_warn("%s: CPU%d SIP register not available\n",
> +			__func__, smp_processor_id());
> +		return;
> +	}
> +
> +	writel(0, swi->sip_reg);
> +}
> +
> +static struct riscv_ipi_ops aclint_swi_ipi_ops = {
> +	.name = "ACLINT-SWI",
> +	.use_for_rfence = true,
> +	.ipi_inject = aclint_swi_send_ipi,
> +	.ipi_clear = aclint_swi_clear_ipi,
> +};
> +
> +static int __init aclint_swi_init(struct device_node *node,
> +				  struct device_node *parent)
> +{
> +	void __iomem *base;
> +	struct aclint_swi *swi;
> +	u32 i, nr_irqs, nr_cpus = 0;
> +
> +	/* Map the registers */
> +	base = of_iomap(node, 0);
> +	if (!base) {
> +		pr_err("%pOFP: could not map registers\n", node);
> +		return -ENODEV;
> +	}
> +
> +	/* Iterarte over each target CPU connected with this ACLINT */
> +	nr_irqs = of_irq_count(node);
> +	for (i = 0; i < nr_irqs; i++) {
> +		struct of_phandle_args parent;
> +		int cpu, hartid;
> +
> +		if (of_irq_parse_one(node, i, &parent)) {
> +			pr_err("%pOFP: failed to parse irq %d.\n",
> +			       node, i);
> +			continue;
> +		}
> +
> +		if (parent.args[0] != RV_IRQ_SOFT) {
> +			pr_err("%pOFP: invalid irq %d (hwirq %d)\n",
> +			       node, i, parent.args[0]);
> +			continue;
> +		}
> +
> +		hartid = riscv_of_parent_hartid(parent.np);
> +		if (hartid < 0) {
> +			pr_warn("failed to parse hart ID for irq %d.\n", i);
> +			continue;
> +		}
> +
> +		cpu = riscv_hartid_to_cpuid(hartid);
> +		if (cpu < 0) {
> +			pr_warn("Invalid cpuid for irq %d\n", i);
> +			continue;
> +		}
> +
> +		swi = per_cpu_ptr(&aclint_swis, cpu);
> +		swi->sip_reg = base + i * sizeof(u32);
> +		nr_cpus++;
> +	}
> +
> +	/* Announce the ACLINT SWI device */
> +	pr_info("%pOFP: providing IPIs for %d CPUs\n", node, nr_cpus);
> +
> +	/* Register the IPI operations */
> +	riscv_set_ipi_ops(&aclint_swi_ipi_ops);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_RISCV_M_MODE
> +IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-mswi", aclint_swi_init);
> +#else
> +IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-sswi", aclint_swi_init);
> +#endif

I'm sorry, but this really isn't an irqchip driver. This is a piece of
arch-specific code that uses *none* of the irq subsystem abstractions
apart from the IRQCHIP_DECLARE() macro.

If you implemented it on top of the IPI irq_domain abstraction, making
your IPIs actual IRQs, use the proper interrupt flows and accounting,
then it would make sense to call it an irqchip driver. But as it
stands, it has no place in drivers/irqchip.

Thanks,

	M.
Anup Patel June 13, 2021, 12:25 p.m. UTC | #2 
On Sun, Jun 13, 2021 at 3:11 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sat, 12 Jun 2021 17:04:17 +0100,
> Anup Patel <anup.patel@wdc.com> wrote:
> >
> > The RISC-V ACLINT provides MSWI and SSWI devices for M-mode and
> > S-mode software interrupts respectively. We add irqchip driver
> > which provide IPI operations based on ACLINT [M|S]SWI devices
> > to the Linux RISC-V kernel.
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > ---
> >  drivers/irqchip/Kconfig          |  11 +++
> >  drivers/irqchip/Makefile         |   1 +
> >  drivers/irqchip/irq-aclint-swi.c | 122 +++++++++++++++++++++++++++++++
> >  3 files changed, 134 insertions(+)
> >  create mode 100644 drivers/irqchip/irq-aclint-swi.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index 62543a4eccc0..2010d493b03b 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -508,6 +508,17 @@ config RISCV_INTC
> >
> >          If you don't know what to do here, say Y.
> >
> > +config RISCV_ACLINT_SWI
> > +     bool "RISC-V Advanced Core Local Interruptor Software Interrupts"
> > +     depends on RISCV
> > +     help
> > +        This enables support for software interrupts using the Advanced
> > +        Core Local Interruptor (ACLINT) found in RISC-V systems.  The
> > +        RISC-V ACLINT provides devices for inter-process interrupt and
> > +        timer functionality.
> > +
> > +        If you don't know what to do here, say Y.
> > +
> >  config SIFIVE_PLIC
> >       bool "SiFive Platform-Level Interrupt Controller"
> >       depends on RISCV
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index f88cbf36a9d2..a6edf6733c1d 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -97,6 +97,7 @@ obj-$(CONFIG_QCOM_PDC)                      += qcom-pdc.o
> >  obj-$(CONFIG_CSKY_MPINTC)            += irq-csky-mpintc.o
> >  obj-$(CONFIG_CSKY_APB_INTC)          += irq-csky-apb-intc.o
> >  obj-$(CONFIG_RISCV_INTC)             += irq-riscv-intc.o
> > +obj-$(CONFIG_RISCV_ACLINT_SWI)               += irq-aclint-swi.o
> >  obj-$(CONFIG_SIFIVE_PLIC)            += irq-sifive-plic.o
> >  obj-$(CONFIG_IMX_IRQSTEER)           += irq-imx-irqsteer.o
> >  obj-$(CONFIG_IMX_INTMUX)             += irq-imx-intmux.o
> > diff --git a/drivers/irqchip/irq-aclint-swi.c b/drivers/irqchip/irq-aclint-swi.c
> > new file mode 100644
> > index 000000000000..f9607072cc7b
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-aclint-swi.c
> > @@ -0,0 +1,122 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + */
> > +
> > +#define pr_fmt(fmt) "aclint-swi: " fmt
> > +#include <linux/cpu.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/smp.h>
> > +
> > +struct aclint_swi {
> > +     void __iomem *sip_reg;
> > +};
> > +static DEFINE_PER_CPU(struct aclint_swi, aclint_swis);
> > +
> > +static void aclint_swi_send_ipi(const struct cpumask *target)
> > +{
> > +     unsigned int cpu;
> > +     struct aclint_swi *swi;
> > +
> > +     for_each_cpu(cpu, target) {
> > +             swi = per_cpu_ptr(&aclint_swis, cpu);
> > +             if (!swi->sip_reg) {
> > +                     pr_warn("%s: CPU%d SIP register not available\n",
> > +                             __func__, cpu);
> > +                     continue;
> > +             }
> > +
> > +             writel(1, swi->sip_reg);
> > +     }
> > +}
> > +
> > +static void aclint_swi_clear_ipi(void)
> > +{
> > +     struct aclint_swi *swi = this_cpu_ptr(&aclint_swis);
> > +
> > +     if (!swi->sip_reg) {
> > +             pr_warn("%s: CPU%d SIP register not available\n",
> > +                     __func__, smp_processor_id());
> > +             return;
> > +     }
> > +
> > +     writel(0, swi->sip_reg);
> > +}
> > +
> > +static struct riscv_ipi_ops aclint_swi_ipi_ops = {
> > +     .name = "ACLINT-SWI",
> > +     .use_for_rfence = true,
> > +     .ipi_inject = aclint_swi_send_ipi,
> > +     .ipi_clear = aclint_swi_clear_ipi,
> > +};
> > +
> > +static int __init aclint_swi_init(struct device_node *node,
> > +                               struct device_node *parent)
> > +{
> > +     void __iomem *base;
> > +     struct aclint_swi *swi;
> > +     u32 i, nr_irqs, nr_cpus = 0;
> > +
> > +     /* Map the registers */
> > +     base = of_iomap(node, 0);
> > +     if (!base) {
> > +             pr_err("%pOFP: could not map registers\n", node);
> > +             return -ENODEV;
> > +     }
> > +
> > +     /* Iterarte over each target CPU connected with this ACLINT */
> > +     nr_irqs = of_irq_count(node);
> > +     for (i = 0; i < nr_irqs; i++) {
> > +             struct of_phandle_args parent;
> > +             int cpu, hartid;
> > +
> > +             if (of_irq_parse_one(node, i, &parent)) {
> > +                     pr_err("%pOFP: failed to parse irq %d.\n",
> > +                            node, i);
> > +                     continue;
> > +             }
> > +
> > +             if (parent.args[0] != RV_IRQ_SOFT) {
> > +                     pr_err("%pOFP: invalid irq %d (hwirq %d)\n",
> > +                            node, i, parent.args[0]);
> > +                     continue;
> > +             }
> > +
> > +             hartid = riscv_of_parent_hartid(parent.np);
> > +             if (hartid < 0) {
> > +                     pr_warn("failed to parse hart ID for irq %d.\n", i);
> > +                     continue;
> > +             }
> > +
> > +             cpu = riscv_hartid_to_cpuid(hartid);
> > +             if (cpu < 0) {
> > +                     pr_warn("Invalid cpuid for irq %d\n", i);
> > +                     continue;
> > +             }
> > +
> > +             swi = per_cpu_ptr(&aclint_swis, cpu);
> > +             swi->sip_reg = base + i * sizeof(u32);
> > +             nr_cpus++;
> > +     }
> > +
> > +     /* Announce the ACLINT SWI device */
> > +     pr_info("%pOFP: providing IPIs for %d CPUs\n", node, nr_cpus);
> > +
> > +     /* Register the IPI operations */
> > +     riscv_set_ipi_ops(&aclint_swi_ipi_ops);
> > +
> > +     return 0;
> > +}
> > +
> > +#ifdef CONFIG_RISCV_M_MODE
> > +IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-mswi", aclint_swi_init);
> > +#else
> > +IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-sswi", aclint_swi_init);
> > +#endif
>
> I'm sorry, but this really isn't an irqchip driver. This is a piece of
> arch-specific code that uses *none* of the irq subsystem abstractions
> apart from the IRQCHIP_DECLARE() macro.

Yes, I was not sure we can call it IRQCHIP hence the RFC PATCH.

Both ACLINT MSWI and SSWI are special devices providing only IPI
support so I will re-think how to fit this.

>
> If you implemented it on top of the IPI irq_domain abstraction, making
> your IPIs actual IRQs, use the proper interrupt flows and accounting,
> then it would make sense to call it an irqchip driver. But as it
> stands, it has no place in drivers/irqchip.

Okay, let me explore IPI irq_domain if it is suitable for this.

Regards,
Anup

>
> Thanks,
>
>         M.
>
> --
> Without deviation from the norm, progress is not possible.
Marc Zyngier June 14, 2021, 9:38 a.m. UTC | #3 
On Sun, 13 Jun 2021 13:25:40 +0100,
Anup Patel <anup@brainfault.org> wrote:
> 
> On Sun, Jun 13, 2021 at 3:11 PM Marc Zyngier <maz@kernel.org> wrote:
> >
> > I'm sorry, but this really isn't an irqchip driver. This is a piece of
> > arch-specific code that uses *none* of the irq subsystem abstractions
> > apart from the IRQCHIP_DECLARE() macro.
> 
> Yes, I was not sure we can call it IRQCHIP hence the RFC PATCH.
> 
> Both ACLINT MSWI and SSWI are special devices providing only IPI
> support so I will re-think how to fit this.

It depends on how you think of IPIs in your architecture.

arm64 (and even now 32bit) have been moved to a mode where IPIs are
normal interrupts, as it helps with other things such as our pseudo
NMIs, and reduces code duplication. MIPS has done the same for a long
time (they don't have dedicated HW for that).

	M.
Anup Patel June 14, 2021, 1:13 p.m. UTC | #4 
On Mon, Jun 14, 2021 at 3:08 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sun, 13 Jun 2021 13:25:40 +0100,
> Anup Patel <anup@brainfault.org> wrote:
> >
> > On Sun, Jun 13, 2021 at 3:11 PM Marc Zyngier <maz@kernel.org> wrote:
> > >
> > > I'm sorry, but this really isn't an irqchip driver. This is a piece of
> > > arch-specific code that uses *none* of the irq subsystem abstractions
> > > apart from the IRQCHIP_DECLARE() macro.
> >
> > Yes, I was not sure we can call it IRQCHIP hence the RFC PATCH.
> >
> > Both ACLINT MSWI and SSWI are special devices providing only IPI
> > support so I will re-think how to fit this.
>
> It depends on how you think of IPIs in your architecture.
>
> arm64 (and even now 32bit) have been moved to a mode where IPIs are
> normal interrupts, as it helps with other things such as our pseudo
> NMIs, and reduces code duplication. MIPS has done the same for a long
> time (they don't have dedicated HW for that).

RISC-V is also moving in a similar direction with the RISC-V advanced
interrupt architecture (AIA) specification which aims at defining an
interrupt controller having MSI support, virtualization support and
scalable for a large number of CPUs. The RISC-V AIA treats IPIs as
normal interrupts.

The RISC-V ACLINT based IPI support is for RISC-V systems which
only need a simple interrupt controller without MSI support and
virtualization support. These systems will not implement RISC-V AIA.

Regards,
Anup

>
>         M.
>
> --
> Without deviation from the norm, progress is not possible.
diff mbox series

Patch

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 62543a4eccc0..2010d493b03b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -508,6 +508,17 @@  config RISCV_INTC
 
 	   If you don't know what to do here, say Y.
 
+config RISCV_ACLINT_SWI
+	bool "RISC-V Advanced Core Local Interruptor Software Interrupts"
+	depends on RISCV
+	help
+	   This enables support for software interrupts using the Advanced
+	   Core Local Interruptor (ACLINT) found in RISC-V systems.  The
+	   RISC-V ACLINT provides devices for inter-process interrupt and
+	   timer functionality.
+
+	   If you don't know what to do here, say Y.
+
 config SIFIVE_PLIC
 	bool "SiFive Platform-Level Interrupt Controller"
 	depends on RISCV
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index f88cbf36a9d2..a6edf6733c1d 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -97,6 +97,7 @@  obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
 obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
 obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
+obj-$(CONFIG_RISCV_ACLINT_SWI)		+= irq-aclint-swi.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
 obj-$(CONFIG_IMX_INTMUX)		+= irq-imx-intmux.o
diff --git a/drivers/irqchip/irq-aclint-swi.c b/drivers/irqchip/irq-aclint-swi.c
new file mode 100644
index 000000000000..f9607072cc7b
--- /dev/null
+++ b/drivers/irqchip/irq-aclint-swi.c
@@ -0,0 +1,122 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#define pr_fmt(fmt) "aclint-swi: " fmt
+#include <linux/cpu.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/smp.h>
+
+struct aclint_swi {
+	void __iomem *sip_reg;
+};
+static DEFINE_PER_CPU(struct aclint_swi, aclint_swis);
+
+static void aclint_swi_send_ipi(const struct cpumask *target)
+{
+	unsigned int cpu;
+	struct aclint_swi *swi;
+
+	for_each_cpu(cpu, target) {
+		swi = per_cpu_ptr(&aclint_swis, cpu);
+		if (!swi->sip_reg) {
+			pr_warn("%s: CPU%d SIP register not available\n",
+				__func__, cpu);
+			continue;
+		}
+
+		writel(1, swi->sip_reg);
+	}
+}
+
+static void aclint_swi_clear_ipi(void)
+{
+	struct aclint_swi *swi = this_cpu_ptr(&aclint_swis);
+
+	if (!swi->sip_reg) {
+		pr_warn("%s: CPU%d SIP register not available\n",
+			__func__, smp_processor_id());
+		return;
+	}
+
+	writel(0, swi->sip_reg);
+}
+
+static struct riscv_ipi_ops aclint_swi_ipi_ops = {
+	.name = "ACLINT-SWI",
+	.use_for_rfence = true,
+	.ipi_inject = aclint_swi_send_ipi,
+	.ipi_clear = aclint_swi_clear_ipi,
+};
+
+static int __init aclint_swi_init(struct device_node *node,
+				  struct device_node *parent)
+{
+	void __iomem *base;
+	struct aclint_swi *swi;
+	u32 i, nr_irqs, nr_cpus = 0;
+
+	/* Map the registers */
+	base = of_iomap(node, 0);
+	if (!base) {
+		pr_err("%pOFP: could not map registers\n", node);
+		return -ENODEV;
+	}
+
+	/* Iterarte over each target CPU connected with this ACLINT */
+	nr_irqs = of_irq_count(node);
+	for (i = 0; i < nr_irqs; i++) {
+		struct of_phandle_args parent;
+		int cpu, hartid;
+
+		if (of_irq_parse_one(node, i, &parent)) {
+			pr_err("%pOFP: failed to parse irq %d.\n",
+			       node, i);
+			continue;
+		}
+
+		if (parent.args[0] != RV_IRQ_SOFT) {
+			pr_err("%pOFP: invalid irq %d (hwirq %d)\n",
+			       node, i, parent.args[0]);
+			continue;
+		}
+
+		hartid = riscv_of_parent_hartid(parent.np);
+		if (hartid < 0) {
+			pr_warn("failed to parse hart ID for irq %d.\n", i);
+			continue;
+		}
+
+		cpu = riscv_hartid_to_cpuid(hartid);
+		if (cpu < 0) {
+			pr_warn("Invalid cpuid for irq %d\n", i);
+			continue;
+		}
+
+		swi = per_cpu_ptr(&aclint_swis, cpu);
+		swi->sip_reg = base + i * sizeof(u32);
+		nr_cpus++;
+	}
+
+	/* Announce the ACLINT SWI device */
+	pr_info("%pOFP: providing IPIs for %d CPUs\n", node, nr_cpus);
+
+	/* Register the IPI operations */
+	riscv_set_ipi_ops(&aclint_swi_ipi_ops);
+
+	return 0;
+}
+
+#ifdef CONFIG_RISCV_M_MODE
+IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-mswi", aclint_swi_init);
+#else
+IRQCHIP_DECLARE(riscv_aclint_swi, "riscv,aclint-sswi", aclint_swi_init);
+#endif