Re: [PATCH v2 7/9] irqchip: Add RISC-V advanced PLIC driver

From: Anup Patel
Date: Tue Jan 17 2023 - 23:37:52 EST

On Tue, Jan 17, 2023 at 12:39 PM Vincent Chen <vincent.chen@xxxxxxxxxx> wrote:
>
> > From: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > Date: Wed, Jan 4, 2023 at 1:19 AM
> > Subject: [PATCH v2 7/9] irqchip: Add RISC-V advanced PLIC driver
> > To: Palmer Dabbelt <palmer@xxxxxxxxxxx>, Paul Walmsley <paul.walmsley@xxxxxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>, Marc Zyngier <maz@xxxxxxxxxx>, Rob Herring <robh+dt@xxxxxxxxxx>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>
> > Cc: Atish Patra <atishp@xxxxxxxxxxxxxx>, Alistair Francis <Alistair.Francis@xxxxxxx>, Anup Patel <anup@xxxxxxxxxxxxxx>, <linux-riscv@xxxxxxxxxxxxxxxxxxx>, <linux-kernel@xxxxxxxxxxxxxxx>, <devicetree@xxxxxxxxxxxxxxx>, Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> >
> >
> > The RISC-V advanced interrupt architecture (AIA) specification defines
> > a new interrupt controller for managing wired interrupts on a RISC-V
> > platform. This new interrupt controller is referred to as advanced
> > platform-level interrupt controller (APLIC) which can forward wired
> > interrupts to CPUs (or HARTs) as local interrupts OR as message
> > signaled interrupts.
> > (For more details refer https://github.com/riscv/riscv-aia)
> >
> I could not find an appropriate place to post my question, so I posted it here.
>
> I am a little concerned about the current MSI IRQ handling in APLIC.
> According to the specification, when domaincfg.DM = 1, the pending bit
> is set to one by a low-to-high transition in the rectified input
> value. When the APLIC forward this interrupt by MSI, the pending bit
> will be cleared regardless of whether the interrupt type is
> level-sensitive or edge-trigger. However, the interrupted service
> routine may not deal with all requests at a time. When there are
> remaining pending requests after leaving the ISR, these requests may
> have no chance to be serviced if the IRQ type of this device is
> level-sensitive. This is because the rectified value of this interrupt
> changes from 0 to 1 only at the beginning. It causes the pending bit
> of this interrupt will not to be asserted again, so APLIC will not
> send the next MSI for this interrupt. Therefore, the ISR doesn't have
> a chance to deal with the remaining requests.
>
> One possible solution to fix this issue is to let the APLIC driver
> check if the rectified value of the serviced interrupt is one after
> returning from its ISR. When the value is 1, it means this device
> still has pending requests. In this case, the APLIC driver can set its
> pending bit by the setipnum register or the setip register. It will
> let APLIC send the next MSI for this device, and the ISR will have a
> chance to deal with the remaining requests.

This is situation and possible solutions are already described in
the section "4.9.2 Special consideration for level-sensitive interrupt
sources" of the AIA specification.

It is a human error on my part for having totally missed adding
relevant code here. Thanks for pointing. I will fix this in the v3 patch.

Regards,
Anup

>
>
>
> > This patch adds an irqchip driver for RISC-V APLIC found on RISC-V
> > platforms.
> >
> > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> > ---
> > drivers/irqchip/Kconfig | 6 +
> > drivers/irqchip/Makefile | 1 +
> > drivers/irqchip/irq-riscv-aplic.c | 670 ++++++++++++++++++++++++++++
> > include/linux/irqchip/riscv-aplic.h | 117 +++++
> > 4 files changed, 794 insertions(+)
> > create mode 100644 drivers/irqchip/irq-riscv-aplic.c
> > create mode 100644 include/linux/irqchip/riscv-aplic.h
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index a1315189a595..936e59fe1f99 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -547,6 +547,12 @@ config SIFIVE_PLIC
> > select IRQ_DOMAIN_HIERARCHY
> > select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
> >
> > +config RISCV_APLIC
> > + bool
> > + depends on RISCV
> > + select IRQ_DOMAIN_HIERARCHY
> > + select GENERIC_MSI_IRQ_DOMAIN
> > +
> > config RISCV_IMSIC
> > bool
> > depends on RISCV
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index 22c723cc6ec8..6154e5bc4228 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -96,6 +96,7 @@ obj-$(CONFIG_QCOM_MPM) += irq-qcom-mpm.o
> > obj-$(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-$(CONFIG_RISCV_APLIC) += irq-riscv-aplic.o
> > obj-$(CONFIG_RISCV_IMSIC) += irq-riscv-imsic.o
> > obj-$(CONFIG_SIFIVE_PLIC) += irq-sifive-plic.o
> > obj-$(CONFIG_IMX_IRQSTEER) += irq-imx-irqsteer.o
> > diff --git a/drivers/irqchip/irq-riscv-aplic.c b/drivers/irqchip/irq-riscv-aplic.c
> > new file mode 100644
> > index 000000000000..63f20892d7d3
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-riscv-aplic.c
> > @@ -0,0 +1,670 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + * Copyright (C) 2022 Ventana Micro Systems Inc.
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/cpu.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip.h>
> > +#include <linux/irqchip/chained_irq.h>
> > +#include <linux/irqchip/riscv-aplic.h>
> > +#include <linux/irqchip/riscv-imsic.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/module.h>
> > +#include <linux/msi.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/smp.h>
> > +
> > +#define APLIC_DEFAULT_PRIORITY 1
> > +#define APLIC_DISABLE_IDELIVERY 0
> > +#define APLIC_ENABLE_IDELIVERY 1
> > +#define APLIC_DISABLE_ITHRESHOLD 1
> > +#define APLIC_ENABLE_ITHRESHOLD 0
> > +
> > +struct aplic_msicfg {
> > + phys_addr_t base_ppn;
> > + u32 hhxs;
> > + u32 hhxw;
> > + u32 lhxs;
> > + u32 lhxw;
> > +};
> > +
> > +struct aplic_idc {
> > + unsigned int hart_index;
> > + void __iomem *regs;
> > + struct aplic_priv *priv;
> > +};
> > +
> > +struct aplic_priv {
> > + struct device *dev;
> > + u32 nr_irqs;
> > + u32 nr_idcs;
> > + void __iomem *regs;
> > + struct irq_domain *irqdomain;
> > + struct aplic_msicfg msicfg;
> > + struct cpumask lmask;
> > +};
> > +
> > +static unsigned int aplic_idc_parent_irq;
> > +static DEFINE_PER_CPU(struct aplic_idc, aplic_idcs);
> > +
> > +static void aplic_irq_unmask(struct irq_data *d)
> > +{
> > + struct aplic_priv *priv = irq_data_get_irq_chip_data(d);
> > +
> > + writel(d->hwirq, priv->regs + APLIC_SETIENUM);
> > +
> > + if (!priv->nr_idcs)
> > + irq_chip_unmask_parent(d);
> > +}
> > +
> > +static void aplic_irq_mask(struct irq_data *d)
> > +{
> > + struct aplic_priv *priv = irq_data_get_irq_chip_data(d);
> > +
> > + writel(d->hwirq, priv->regs + APLIC_CLRIENUM);
> > +
> > + if (!priv->nr_idcs)
> > + irq_chip_mask_parent(d);
> > +}
> > +
> > +static int aplic_set_type(struct irq_data *d, unsigned int type)
> > +{
> > + u32 val = 0;
> > + void __iomem *sourcecfg;
> > + struct aplic_priv *priv = irq_data_get_irq_chip_data(d);
> > +
> > + switch (type) {
> > + case IRQ_TYPE_NONE:
> > + val = APLIC_SOURCECFG_SM_INACTIVE;
> > + break;
> > + case IRQ_TYPE_LEVEL_LOW:
> > + val = APLIC_SOURCECFG_SM_LEVEL_LOW;
> > + break;
> > + case IRQ_TYPE_LEVEL_HIGH:
> > + val = APLIC_SOURCECFG_SM_LEVEL_HIGH;
> > + break;
> > + case IRQ_TYPE_EDGE_FALLING:
> > + val = APLIC_SOURCECFG_SM_EDGE_FALL;
> > + break;
> > + case IRQ_TYPE_EDGE_RISING:
> > + val = APLIC_SOURCECFG_SM_EDGE_RISE;
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + sourcecfg = priv->regs + APLIC_SOURCECFG_BASE;
> > + sourcecfg += (d->hwirq - 1) * sizeof(u32);
> > + writel(val, sourcecfg);
> > +
> > + return 0;
> > +}
> > +
> > +#ifdef CONFIG_SMP
> > +static int aplic_set_affinity(struct irq_data *d,
> > + const struct cpumask *mask_val, bool force)
> > +{
> > + struct aplic_priv *priv = irq_data_get_irq_chip_data(d);
> > + struct aplic_idc *idc;
> > + unsigned int cpu, val;
> > + struct cpumask amask;
> > + void __iomem *target;
> > +
> > + if (!priv->nr_idcs)
> > + return irq_chip_set_affinity_parent(d, mask_val, force);
> > +
> > + cpumask_and(&amask, &priv->lmask, mask_val);
> > +
> > + if (force)
> > + cpu = cpumask_first(&amask);
> > + else
> > + cpu = cpumask_any_and(&amask, cpu_online_mask);
> > +
> > + if (cpu >= nr_cpu_ids)
> > + return -EINVAL;
> > +
> > + idc = per_cpu_ptr(&aplic_idcs, cpu);
> > + target = priv->regs + APLIC_TARGET_BASE;
> > + target += (d->hwirq - 1) * sizeof(u32);
> > + val = idc->hart_index & APLIC_TARGET_HART_IDX_MASK;
> > + val <<= APLIC_TARGET_HART_IDX_SHIFT;
> > + val |= APLIC_DEFAULT_PRIORITY;
> > + writel(val, target);
> > +
> > + irq_data_update_effective_affinity(d, cpumask_of(cpu));
> > +
> > + return IRQ_SET_MASK_OK_DONE;
> > +}
> > +#endif
> > +
> > +static struct irq_chip aplic_chip = {
> > + .name = "RISC-V APLIC",
> > + .irq_mask = aplic_irq_mask,
> > + .irq_unmask = aplic_irq_unmask,
> > + .irq_set_type = aplic_set_type,
> > +#ifdef CONFIG_SMP
> > + .irq_set_affinity = aplic_set_affinity,
> > +#endif
> > + .flags = IRQCHIP_SET_TYPE_MASKED |
> > + IRQCHIP_SKIP_SET_WAKE |
> > + IRQCHIP_MASK_ON_SUSPEND,
> > +};
> > +
> > +static int aplic_irqdomain_translate(struct irq_domain *d,
> > + struct irq_fwspec *fwspec,
> > + unsigned long *hwirq,
> > + unsigned int *type)
> > +{
> > + if (WARN_ON(fwspec->param_count < 2))
> > + return -EINVAL;
> > + if (WARN_ON(!fwspec->param[0]))
> > + return -EINVAL;
> > +
> > + *hwirq = fwspec->param[0];
> > + *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> > +
> > + WARN_ON(*type == IRQ_TYPE_NONE);
> > +
> > + return 0;
> > +}
> > +
> > +static int aplic_irqdomain_msi_alloc(struct irq_domain *domain,
> > + unsigned int virq, unsigned int nr_irqs,
> > + void *arg)
> > +{
> > + int i, ret;
> > + unsigned int type;
> > + irq_hw_number_t hwirq;
> > + struct irq_fwspec *fwspec = arg;
> > + struct aplic_priv *priv = platform_msi_get_host_data(domain);
> > +
> > + ret = aplic_irqdomain_translate(domain, fwspec, &hwirq, &type);
> > + if (ret)
> > + return ret;
> > +
> > + ret = platform_msi_device_domain_alloc(domain, virq, nr_irqs);
> > + if (ret)
> > + return ret;
> > +
> > + for (i = 0; i < nr_irqs; i++)
> > + irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> > + &aplic_chip, priv);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct irq_domain_ops aplic_irqdomain_msi_ops = {
> > + .translate = aplic_irqdomain_translate,
> > + .alloc = aplic_irqdomain_msi_alloc,
> > + .free = platform_msi_device_domain_free,
> > +};
> > +
> > +static int aplic_irqdomain_idc_alloc(struct irq_domain *domain,
> > + unsigned int virq, unsigned int nr_irqs,
> > + void *arg)
> > +{
> > + int i, ret;
> > + unsigned int type;
> > + irq_hw_number_t hwirq;
> > + struct irq_fwspec *fwspec = arg;
> > + struct aplic_priv *priv = domain->host_data;
> > +
> > + ret = aplic_irqdomain_translate(domain, fwspec, &hwirq, &type);
> > + if (ret)
> > + return ret;
> > +
> > + for (i = 0; i < nr_irqs; i++) {
> > + irq_domain_set_info(domain, virq + i, hwirq + i,
> > + &aplic_chip, priv, handle_simple_irq,
> > + NULL, NULL);
> > + irq_set_affinity(virq + i, &priv->lmask);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct irq_domain_ops aplic_irqdomain_idc_ops = {
> > + .translate = aplic_irqdomain_translate,
> > + .alloc = aplic_irqdomain_idc_alloc,
> > + .free = irq_domain_free_irqs_top,
> > +};
> > +
> > +static void aplic_init_hw_irqs(struct aplic_priv *priv)
> > +{
> > + int i;
> > +
> > + /* Disable all interrupts */
> > + for (i = 0; i <= priv->nr_irqs; i += 32)
> > + writel(-1U, priv->regs + APLIC_CLRIE_BASE +
> > + (i / 32) * sizeof(u32));
> > +
> > + /* Set interrupt type and default priority for all interrupts */
> > + for (i = 1; i <= priv->nr_irqs; i++) {
> > + writel(0, priv->regs + APLIC_SOURCECFG_BASE +
> > + (i - 1) * sizeof(u32));
> > + writel(APLIC_DEFAULT_PRIORITY,
> > + priv->regs + APLIC_TARGET_BASE +
> > + (i - 1) * sizeof(u32));
> > + }
> > +
> > + /* Clear APLIC domaincfg */
> > + writel(0, priv->regs + APLIC_DOMAINCFG);
> > +}
> > +
> > +static void aplic_init_hw_global(struct aplic_priv *priv)
> > +{
> > + u32 val;
> > +#ifdef CONFIG_RISCV_M_MODE
> > + u32 valH;
> > +
> > + if (!priv->nr_idcs) {
> > + val = priv->msicfg.base_ppn;
> > + valH = (priv->msicfg.base_ppn >> 32) &
> > + APLIC_xMSICFGADDRH_BAPPN_MASK;
> > + valH |= (priv->msicfg.lhxw & APLIC_xMSICFGADDRH_LHXW_MASK)
> > + << APLIC_xMSICFGADDRH_LHXW_SHIFT;
> > + valH |= (priv->msicfg.hhxw & APLIC_xMSICFGADDRH_HHXW_MASK)
> > + << APLIC_xMSICFGADDRH_HHXW_SHIFT;
> > + valH |= (priv->msicfg.lhxs & APLIC_xMSICFGADDRH_LHXS_MASK)
> > + << APLIC_xMSICFGADDRH_LHXS_SHIFT;
> > + valH |= (priv->msicfg.hhxs & APLIC_xMSICFGADDRH_HHXS_MASK)
> > + << APLIC_xMSICFGADDRH_HHXS_SHIFT;
> > + writel(val, priv->regs + APLIC_xMSICFGADDR);
> > + writel(valH, priv->regs + APLIC_xMSICFGADDRH);
> > + }
> > +#endif
> > +
> > + /* Setup APLIC domaincfg register */
> > + val = readl(priv->regs + APLIC_DOMAINCFG);
> > + val |= APLIC_DOMAINCFG_IE;
> > + if (!priv->nr_idcs)
> > + val |= APLIC_DOMAINCFG_DM;
> > + writel(val, priv->regs + APLIC_DOMAINCFG);
> > + if (readl(priv->regs + APLIC_DOMAINCFG) != val)
> > + dev_warn(priv->dev,
> > + "unable to write 0x%x in domaincfg\n", val);
> > +}
> > +
> > +static void aplic_msi_write_msg(struct msi_desc *desc, struct msi_msg *msg)
> > +{
> > + unsigned int group_index, hart_index, guest_index, val;
> > + struct device *dev = msi_desc_to_dev(desc);
> > + struct aplic_priv *priv = dev_get_drvdata(dev);
> > + struct irq_data *d = irq_get_irq_data(desc->irq);
> > + struct aplic_msicfg *mc = &priv->msicfg;
> > + phys_addr_t tppn, tbppn, msg_addr;
> > + void __iomem *target;
> > +
> > + /* For zeroed MSI, simply write zero into the target register */
> > + if (!msg->address_hi && !msg->address_lo && !msg->data) {
> > + target = priv->regs + APLIC_TARGET_BASE;
> > + target += (d->hwirq - 1) * sizeof(u32);
> > + writel(0, target);
> > + return;
> > + }
> > +
> > + /* Sanity check on message data */
> > + WARN_ON(msg->data > APLIC_TARGET_EIID_MASK);
> > +
> > + /* Compute target MSI address */
> > + msg_addr = (((u64)msg->address_hi) << 32) | msg->address_lo;
> > + tppn = msg_addr >> APLIC_xMSICFGADDR_PPN_SHIFT;
> > +
> > + /* Compute target HART Base PPN */
> > + tbppn = tppn;
> > + tbppn &= ~APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> > + tbppn &= ~APLIC_xMSICFGADDR_PPN_LHX(mc->lhxw, mc->lhxs);
> > + tbppn &= ~APLIC_xMSICFGADDR_PPN_HHX(mc->hhxw, mc->hhxs);
> > + WARN_ON(tbppn != mc->base_ppn);
> > +
> > + /* Compute target group and hart indexes */
> > + group_index = (tppn >> APLIC_xMSICFGADDR_PPN_HHX_SHIFT(mc->hhxs)) &
> > + APLIC_xMSICFGADDR_PPN_HHX_MASK(mc->hhxw);
> > + hart_index = (tppn >> APLIC_xMSICFGADDR_PPN_LHX_SHIFT(mc->lhxs)) &
> > + APLIC_xMSICFGADDR_PPN_LHX_MASK(mc->lhxw);
> > + hart_index |= (group_index << mc->lhxw);
> > + WARN_ON(hart_index > APLIC_TARGET_HART_IDX_MASK);
> > +
> > + /* Compute target guest index */
> > + guest_index = tppn & APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> > + WARN_ON(guest_index > APLIC_TARGET_GUEST_IDX_MASK);
> > +
> > + /* Update IRQ TARGET register */
> > + target = priv->regs + APLIC_TARGET_BASE;
> > + target += (d->hwirq - 1) * sizeof(u32);
> > + val = (hart_index & APLIC_TARGET_HART_IDX_MASK)
> > + << APLIC_TARGET_HART_IDX_SHIFT;
> > + val |= (guest_index & APLIC_TARGET_GUEST_IDX_MASK)
> > + << APLIC_TARGET_GUEST_IDX_SHIFT;
> > + val |= (msg->data & APLIC_TARGET_EIID_MASK);
> > + writel(val, target);
> > +}
> > +
> > +static int aplic_setup_msi(struct aplic_priv *priv)
> > +{
> > + struct device *dev = priv->dev;
> > + struct aplic_msicfg *mc = &priv->msicfg;
> > + const struct imsic_global_config *imsic_global;
> > +
> > + /*
> > + * The APLIC outgoing MSI config registers assume target MSI
> > + * controller to be RISC-V AIA IMSIC controller.
> > + */
> > + imsic_global = imsic_get_global_config();
> > + if (!imsic_global) {
> > + dev_err(dev, "IMSIC global config not found\n");
> > + return -ENODEV;
> > + }
> > +
> > + /* Find number of guest index bits (LHXS) */
> > + mc->lhxs = imsic_global->guest_index_bits;
> > + if (APLIC_xMSICFGADDRH_LHXS_MASK < mc->lhxs) {
> > + dev_err(dev, "IMSIC guest index bits big for APLIC LHXS\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Find number of HART index bits (LHXW) */
> > + mc->lhxw = imsic_global->hart_index_bits;
> > + if (APLIC_xMSICFGADDRH_LHXW_MASK < mc->lhxw) {
> > + dev_err(dev, "IMSIC hart index bits big for APLIC LHXW\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Find number of group index bits (HHXW) */
> > + mc->hhxw = imsic_global->group_index_bits;
> > + if (APLIC_xMSICFGADDRH_HHXW_MASK < mc->hhxw) {
> > + dev_err(dev, "IMSIC group index bits big for APLIC HHXW\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Find first bit position of group index (HHXS) */
> > + mc->hhxs = imsic_global->group_index_shift;
> > + if (mc->hhxs < (2 * APLIC_xMSICFGADDR_PPN_SHIFT)) {
> > + dev_err(dev, "IMSIC group index shift should be >= %d\n",
> > + (2 * APLIC_xMSICFGADDR_PPN_SHIFT));
> > + return -EINVAL;
> > + }
> > + mc->hhxs -= (2 * APLIC_xMSICFGADDR_PPN_SHIFT);
> > + if (APLIC_xMSICFGADDRH_HHXS_MASK < mc->hhxs) {
> > + dev_err(dev, "IMSIC group index shift big for APLIC HHXS\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Compute PPN base */
> > + mc->base_ppn = imsic_global->base_addr >> APLIC_xMSICFGADDR_PPN_SHIFT;
> > + mc->base_ppn &= ~APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> > + mc->base_ppn &= ~APLIC_xMSICFGADDR_PPN_LHX(mc->lhxw, mc->lhxs);
> > + mc->base_ppn &= ~APLIC_xMSICFGADDR_PPN_HHX(mc->hhxw, mc->hhxs);
> > +
> > + /* Use all possible CPUs as lmask */
> > + cpumask_copy(&priv->lmask, cpu_possible_mask);
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * To handle an APLIC IDC interrupts, we just read the CLAIMI register
> > + * which will return highest priority pending interrupt and clear the
> > + * pending bit of the interrupt. This process is repeated until CLAIMI
> > + * register return zero value.
> > + */
> > +static void aplic_idc_handle_irq(struct irq_desc *desc)
> > +{
> > + struct aplic_idc *idc = this_cpu_ptr(&aplic_idcs);
> > + struct irq_chip *chip = irq_desc_get_chip(desc);
> > + irq_hw_number_t hw_irq;
> > + int irq;
> > +
> > + chained_irq_enter(chip, desc);
> > +
> > + while ((hw_irq = readl(idc->regs + APLIC_IDC_CLAIMI))) {
> > + hw_irq = hw_irq >> APLIC_IDC_TOPI_ID_SHIFT;
> > + irq = irq_find_mapping(idc->priv->irqdomain, hw_irq);
> > +
> > + if (unlikely(irq <= 0))
> > + pr_warn_ratelimited("hw_irq %lu mapping not found\n",
> > + hw_irq);
> > + else
> > + generic_handle_irq(irq);
> > + }
> > +
> > + chained_irq_exit(chip, desc);
> > +}
> > +
> > +static void aplic_idc_set_delivery(struct aplic_idc *idc, bool en)
> > +{
> > + u32 de = (en) ? APLIC_ENABLE_IDELIVERY : APLIC_DISABLE_IDELIVERY;
> > + u32 th = (en) ? APLIC_ENABLE_ITHRESHOLD : APLIC_DISABLE_ITHRESHOLD;
> > +
> > + /* Priority must be less than threshold for interrupt triggering */
> > + writel(th, idc->regs + APLIC_IDC_ITHRESHOLD);
> > +
> > + /* Delivery must be set to 1 for interrupt triggering */
> > + writel(de, idc->regs + APLIC_IDC_IDELIVERY);
> > +}
> > +
> > +static int aplic_idc_dying_cpu(unsigned int cpu)
> > +{
> > + if (aplic_idc_parent_irq)
> > + disable_percpu_irq(aplic_idc_parent_irq);
> > +
> > + return 0;
> > +}
> > +
> > +static int aplic_idc_starting_cpu(unsigned int cpu)
> > +{
> > + if (aplic_idc_parent_irq)
> > + enable_percpu_irq(aplic_idc_parent_irq,
> > + irq_get_trigger_type(aplic_idc_parent_irq));
> > +
> > + return 0;
> > +}
> > +
> > +static int aplic_setup_idc(struct aplic_priv *priv)
> > +{
> > + int i, j, rc, cpu, setup_count = 0;
> > + struct device_node *node = priv->dev->of_node;
> > + struct device *dev = priv->dev;
> > + struct of_phandle_args parent;
> > + struct irq_domain *domain;
> > + unsigned long hartid;
> > + struct aplic_idc *idc;
> > + u32 val;
> > +
> > + /* Setup per-CPU IDC and target CPU mask */
> > + for (i = 0; i < priv->nr_idcs; i++) {
> > + if (of_irq_parse_one(node, i, &parent)) {
> > + dev_err(dev, "failed to parse parent for IDC%d.\n",
> > + i);
> > + return -EIO;
> > + }
> > +
> > + /* Skip IDCs which do not connect to external interrupts */
> > + if (parent.args[0] != RV_IRQ_EXT)
> > + continue;
> > +
> > + rc = riscv_of_parent_hartid(parent.np, &hartid);
> > + if (rc) {
> > + dev_err(dev, "failed to parse hart ID for IDC%d.\n",
> > + i);
> > + return rc;
> > + }
> > +
> > + cpu = riscv_hartid_to_cpuid(hartid);
> > + if (cpu < 0) {
> > + dev_warn(dev, "invalid cpuid for IDC%d\n", i);
> > + continue;
> > + }
> > +
> > + cpumask_set_cpu(cpu, &priv->lmask);
> > +
> > + idc = per_cpu_ptr(&aplic_idcs, cpu);
> > + WARN_ON(idc->priv);
> > +
> > + idc->hart_index = i;
> > + idc->regs = priv->regs + APLIC_IDC_BASE + i * APLIC_IDC_SIZE;
> > + idc->priv = priv;
> > +
> > + aplic_idc_set_delivery(idc, true);
> > +
> > + /*
> > + * Boot cpu might not have APLIC hart_index = 0 so check
> > + * and update target registers of all interrupts.
> > + */
> > + if (cpu == smp_processor_id() && idc->hart_index) {
> > + val = idc->hart_index & APLIC_TARGET_HART_IDX_MASK;
> > + val <<= APLIC_TARGET_HART_IDX_SHIFT;
> > + val |= APLIC_DEFAULT_PRIORITY;
> > + for (j = 1; j <= priv->nr_irqs; j++)
> > + writel(val, priv->regs + APLIC_TARGET_BASE +
> > + (j - 1) * sizeof(u32));
> > + }
> > +
> > + setup_count++;
> > + }
> > +
> > + /* Find parent domain and register chained handler */
> > + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
> > + DOMAIN_BUS_ANY);
> > + if (!aplic_idc_parent_irq && domain) {
> > + aplic_idc_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT);
> > + if (aplic_idc_parent_irq) {
> > + irq_set_chained_handler(aplic_idc_parent_irq,
> > + aplic_idc_handle_irq);
> > +
> > + /*
> > + * Setup CPUHP notifier to enable IDC parent
> > + * interrupt on all CPUs
> > + */
> > + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
> > + "irqchip/riscv/aplic:starting",
> > + aplic_idc_starting_cpu,
> > + aplic_idc_dying_cpu);
> > + }
> > + }
> > +
> > + /* Fail if we were not able to setup IDC for any CPU */
> > + return (setup_count) ? 0 : -ENODEV;
> > +}
> > +
> > +static int aplic_probe(struct platform_device *pdev)
> > +{
> > + struct device_node *node = pdev->dev.of_node;
> > + struct device *dev = &pdev->dev;
> > + struct aplic_priv *priv;
> > + struct resource *regs;
> > + phys_addr_t pa;
> > + int rc;
> > +
> > + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + if (!regs) {
> > + dev_err(dev, "cannot find registers resource\n");
> > + return -ENOENT;
> > + }
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > + platform_set_drvdata(pdev, priv);
> > + priv->dev = dev;
> > +
> > + priv->regs = devm_ioremap(dev, regs->start, resource_size(regs));
> > + if (WARN_ON(!priv->regs)) {
> > + dev_err(dev, "failed ioremap registers\n");
> > + return -EIO;
> > + }
> > +
> > + of_property_read_u32(node, "riscv,num-sources", &priv->nr_irqs);
> > + if (!priv->nr_irqs) {
> > + dev_err(dev, "failed to get number of interrupt sources\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* Setup initial state APLIC interrupts */
> > + aplic_init_hw_irqs(priv);
> > +
> > + /*
> > + * Setup IDCs or MSIs based on parent interrupts in DT node
> > + *
> > + * If "msi-parent" DT property is present then we ignore the
> > + * APLIC IDCs which forces the APLIC driver to use MSI mode.
> > + */
> > + priv->nr_idcs = of_property_read_bool(node, "msi-parent") ?
> > + 0 : of_irq_count(node);
> > + if (priv->nr_idcs)
> > + rc = aplic_setup_idc(priv);
> > + else
> > + rc = aplic_setup_msi(priv);
> > + if (rc)
> > + return rc;
> > +
> > + /* Setup global config and interrupt delivery */
> > + aplic_init_hw_global(priv);
> > +
> > + /* Create irq domain instance for the APLIC */
> > + if (priv->nr_idcs)
> > + priv->irqdomain = irq_domain_create_linear(
> > + of_node_to_fwnode(node),
> > + priv->nr_irqs + 1,
> > + &aplic_irqdomain_idc_ops,
> > + priv);
> > + else
> > + priv->irqdomain = platform_msi_create_device_domain(dev,
> > + priv->nr_irqs + 1,
> > + aplic_msi_write_msg,
> > + &aplic_irqdomain_msi_ops,
> > + priv);
> > + if (!priv->irqdomain) {
> > + dev_err(dev, "failed to add irq domain\n");
> > + return -ENOMEM;
> > + }
> > +
> > + /* Advertise the interrupt controller */
> > + if (priv->nr_idcs) {
> > + dev_info(dev, "%d interrupts directly connected to %d CPUs\n",
> > + priv->nr_irqs, priv->nr_idcs);
> > + } else {
> > + pa = priv->msicfg.base_ppn << APLIC_xMSICFGADDR_PPN_SHIFT;
> > + dev_info(dev, "%d interrupts forwared to MSI base %pa\n",
> > + priv->nr_irqs, &pa);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int aplic_remove(struct platform_device *pdev)
> > +{
> > + struct aplic_priv *priv = platform_get_drvdata(pdev);
> > +
> > + irq_domain_remove(priv->irqdomain);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct of_device_id aplic_match[] = {
> > + { .compatible = "riscv,aplic" },
> > + {}
> > +};
> > +
> > +static struct platform_driver aplic_driver = {
> > + .driver = {
> > + .name = "riscv-aplic",
> > + .of_match_table = aplic_match,
> > + },
> > + .probe = aplic_probe,
> > + .remove = aplic_remove,
> > +};
> > +
> > +static int __init aplic_init(void)
> > +{
> > + return platform_driver_register(&aplic_driver);
> > +}
> > +core_initcall(aplic_init);
> > diff --git a/include/linux/irqchip/riscv-aplic.h b/include/linux/irqchip/riscv-aplic.h
> > new file mode 100644
> > index 000000000000..88177eefd411
> > --- /dev/null
> > +++ b/include/linux/irqchip/riscv-aplic.h
> > @@ -0,0 +1,117 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> > + * Copyright (C) 2022 Ventana Micro Systems Inc.
> > + */
> > +#ifndef __LINUX_IRQCHIP_RISCV_APLIC_H
> > +#define __LINUX_IRQCHIP_RISCV_APLIC_H
> > +
> > +#include <linux/bitops.h>
> > +
> > +#define APLIC_MAX_IDC BIT(14)
> > +#define APLIC_MAX_SOURCE 1024
> > +
> > +#define APLIC_DOMAINCFG 0x0000
> > +#define APLIC_DOMAINCFG_RDONLY 0x80000000
> > +#define APLIC_DOMAINCFG_IE BIT(8)
> > +#define APLIC_DOMAINCFG_DM BIT(2)
> > +#define APLIC_DOMAINCFG_BE BIT(0)
> > +
> > +#define APLIC_SOURCECFG_BASE 0x0004
> > +#define APLIC_SOURCECFG_D BIT(10)
> > +#define APLIC_SOURCECFG_CHILDIDX_MASK 0x000003ff
> > +#define APLIC_SOURCECFG_SM_MASK 0x00000007
> > +#define APLIC_SOURCECFG_SM_INACTIVE 0x0
> > +#define APLIC_SOURCECFG_SM_DETACH 0x1
> > +#define APLIC_SOURCECFG_SM_EDGE_RISE 0x4
> > +#define APLIC_SOURCECFG_SM_EDGE_FALL 0x5
> > +#define APLIC_SOURCECFG_SM_LEVEL_HIGH 0x6
> > +#define APLIC_SOURCECFG_SM_LEVEL_LOW 0x7
> > +
> > +#define APLIC_MMSICFGADDR 0x1bc0
> > +#define APLIC_MMSICFGADDRH 0x1bc4
> > +#define APLIC_SMSICFGADDR 0x1bc8
> > +#define APLIC_SMSICFGADDRH 0x1bcc
> > +
> > +#ifdef CONFIG_RISCV_M_MODE
> > +#define APLIC_xMSICFGADDR APLIC_MMSICFGADDR
> > +#define APLIC_xMSICFGADDRH APLIC_MMSICFGADDRH
> > +#else
> > +#define APLIC_xMSICFGADDR APLIC_SMSICFGADDR
> > +#define APLIC_xMSICFGADDRH APLIC_SMSICFGADDRH
> > +#endif
> > +
> > +#define APLIC_xMSICFGADDRH_L BIT(31)
> > +#define APLIC_xMSICFGADDRH_HHXS_MASK 0x1f
> > +#define APLIC_xMSICFGADDRH_HHXS_SHIFT 24
> > +#define APLIC_xMSICFGADDRH_LHXS_MASK 0x7
> > +#define APLIC_xMSICFGADDRH_LHXS_SHIFT 20
> > +#define APLIC_xMSICFGADDRH_HHXW_MASK 0x7
> > +#define APLIC_xMSICFGADDRH_HHXW_SHIFT 16
> > +#define APLIC_xMSICFGADDRH_LHXW_MASK 0xf
> > +#define APLIC_xMSICFGADDRH_LHXW_SHIFT 12
> > +#define APLIC_xMSICFGADDRH_BAPPN_MASK 0xfff
> > +
> > +#define APLIC_xMSICFGADDR_PPN_SHIFT 12
> > +
> > +#define APLIC_xMSICFGADDR_PPN_HART(__lhxs) \
> > + (BIT(__lhxs) - 1)
> > +
> > +#define APLIC_xMSICFGADDR_PPN_LHX_MASK(__lhxw) \
> > + (BIT(__lhxw) - 1)
> > +#define APLIC_xMSICFGADDR_PPN_LHX_SHIFT(__lhxs) \
> > + ((__lhxs))
> > +#define APLIC_xMSICFGADDR_PPN_LHX(__lhxw, __lhxs) \
> > + (APLIC_xMSICFGADDR_PPN_LHX_MASK(__lhxw) << \
> > + APLIC_xMSICFGADDR_PPN_LHX_SHIFT(__lhxs))
> > +
> > +#define APLIC_xMSICFGADDR_PPN_HHX_MASK(__hhxw) \
> > + (BIT(__hhxw) - 1)
> > +#define APLIC_xMSICFGADDR_PPN_HHX_SHIFT(__hhxs) \
> > + ((__hhxs) + APLIC_xMSICFGADDR_PPN_SHIFT)
> > +#define APLIC_xMSICFGADDR_PPN_HHX(__hhxw, __hhxs) \
> > + (APLIC_xMSICFGADDR_PPN_HHX_MASK(__hhxw) << \
> > + APLIC_xMSICFGADDR_PPN_HHX_SHIFT(__hhxs))
> > +
> > +#define APLIC_SETIP_BASE 0x1c00
> > +#define APLIC_SETIPNUM 0x1cdc
> > +
> > +#define APLIC_CLRIP_BASE 0x1d00
> > +#define APLIC_CLRIPNUM 0x1ddc
> > +
> > +#define APLIC_SETIE_BASE 0x1e00
> > +#define APLIC_SETIENUM 0x1edc
> > +
> > +#define APLIC_CLRIE_BASE 0x1f00
> > +#define APLIC_CLRIENUM 0x1fdc
> > +
> > +#define APLIC_SETIPNUM_LE 0x2000
> > +#define APLIC_SETIPNUM_BE 0x2004
> > +
> > +#define APLIC_GENMSI 0x3000
> > +
> > +#define APLIC_TARGET_BASE 0x3004
> > +#define APLIC_TARGET_HART_IDX_SHIFT 18
> > +#define APLIC_TARGET_HART_IDX_MASK 0x3fff
> > +#define APLIC_TARGET_GUEST_IDX_SHIFT 12
> > +#define APLIC_TARGET_GUEST_IDX_MASK 0x3f
> > +#define APLIC_TARGET_IPRIO_MASK 0xff
> > +#define APLIC_TARGET_EIID_MASK 0x7ff
> > +
> > +#define APLIC_IDC_BASE 0x4000
> > +#define APLIC_IDC_SIZE 32
> > +
> > +#define APLIC_IDC_IDELIVERY 0x00
> > +
> > +#define APLIC_IDC_IFORCE 0x04
> > +
> > +#define APLIC_IDC_ITHRESHOLD 0x08
> > +
> > +#define APLIC_IDC_TOPI 0x18
> > +#define APLIC_IDC_TOPI_ID_SHIFT 16
> > +#define APLIC_IDC_TOPI_ID_MASK 0x3ff
> > +#define APLIC_IDC_TOPI_PRIO_MASK 0xff
> > +
> > +#define APLIC_IDC_CLAIMI 0x1c
> > +
> > +#endif
> > --
> > 2.34.1
> >
> >
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