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References: <20230613153415.350528-1-apatel@ventanamicro.com> <20230613153415.350528-9-apatel@ventanamicro.com>
In-Reply-To: <20230613153415.350528-9-apatel@ventanamicro.com>
From:   Saravana Kannan <saravanak@google.com>
Date:   Thu, 15 Jun 2023 12:17:08 -0700
Message-ID: <CAGETcx-hoPNanAwe4++6roqBXwSdc7z6Ei=-r9z6qFG1U7xVXg@mail.gmail.com>
Subject: Re: [PATCH v4 08/10] irqchip: Add RISC-V advanced PLIC driver
To:     Anup Patel <apatel@ventanamicro.com>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Atish Patra <atishp@atishpatra.org>,
        Andrew Jones <ajones@ventanamicro.com>,
        Conor Dooley <conor@kernel.org>,
        Anup Patel <anup@brainfault.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, iommu@lists.linux.dev
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On Tue, Jun 13, 2023 at 8:35=E2=80=AFAM Anup Patel <apatel@ventanamicro.com=
> wrote:
>
> 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)
>
> This patch adds an irqchip driver for RISC-V APLIC found on RISC-V
> platforms.
>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  drivers/irqchip/Kconfig             |   6 +
>  drivers/irqchip/Makefile            |   1 +
>  drivers/irqchip/irq-riscv-aplic.c   | 765 ++++++++++++++++++++++++++++
>  include/linux/irqchip/riscv-aplic.h | 119 +++++
>  4 files changed, 891 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 d700980372ef..834c0329f583 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -544,6 +544,12 @@ 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
> +
>  config RISCV_IMSIC
>         bool
>         depends on RISCV
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 577bde3e986b..438b8e1a152c 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -95,6 +95,7 @@ obj-$(CONFIG_QCOM_MPM)                        +=3D irq-=
qcom-mpm.o
>  obj-$(CONFIG_CSKY_MPINTC)              +=3D irq-csky-mpintc.o
>  obj-$(CONFIG_CSKY_APB_INTC)            +=3D irq-csky-apb-intc.o
>  obj-$(CONFIG_RISCV_INTC)               +=3D irq-riscv-intc.o
> +obj-$(CONFIG_RISCV_APLIC)              +=3D irq-riscv-aplic.o
>  obj-$(CONFIG_RISCV_IMSIC)              +=3D irq-riscv-imsic.o
>  obj-$(CONFIG_SIFIVE_PLIC)              +=3D irq-sifive-plic.o
>  obj-$(CONFIG_IMX_IRQSTEER)             +=3D irq-imx-irqsteer.o
> diff --git a/drivers/irqchip/irq-riscv-aplic.c b/drivers/irqchip/irq-risc=
v-aplic.c
> new file mode 100644
> index 000000000000..1e710fdf5608
> --- /dev/null
> +++ b/drivers/irqchip/irq-riscv-aplic.c
> @@ -0,0 +1,765 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Western Digital Corporation or its affiliates.
> + * Copyright (C) 2022 Ventana Micro Systems Inc.
> + */
> +
> +#define pr_fmt(fmt) "riscv-aplic: " fmt
> +#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/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 fwnode_handle    *fwnode;
> +       u32                     gsi_base;
> +       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 =3D 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 =3D 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 =3D 0;
> +       void __iomem *sourcecfg;
> +       struct aplic_priv *priv =3D irq_data_get_irq_chip_data(d);
> +
> +       switch (type) {
> +       case IRQ_TYPE_NONE:
> +               val =3D APLIC_SOURCECFG_SM_INACTIVE;
> +               break;
> +       case IRQ_TYPE_LEVEL_LOW:
> +               val =3D APLIC_SOURCECFG_SM_LEVEL_LOW;
> +               break;
> +       case IRQ_TYPE_LEVEL_HIGH:
> +               val =3D APLIC_SOURCECFG_SM_LEVEL_HIGH;
> +               break;
> +       case IRQ_TYPE_EDGE_FALLING:
> +               val =3D APLIC_SOURCECFG_SM_EDGE_FALL;
> +               break;
> +       case IRQ_TYPE_EDGE_RISING:
> +               val =3D APLIC_SOURCECFG_SM_EDGE_RISE;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       sourcecfg =3D priv->regs + APLIC_SOURCECFG_BASE;
> +       sourcecfg +=3D (d->hwirq - 1) * sizeof(u32);
> +       writel(val, sourcecfg);
> +
> +       return 0;
> +}
> +
> +static void aplic_irq_eoi(struct irq_data *d)
> +{
> +       struct aplic_priv *priv =3D irq_data_get_irq_chip_data(d);
> +       u32 reg_off, reg_mask;
> +
> +       /*
> +        * EOI handling only required only for level-triggered
> +        * interrupts in APLIC MSI mode.
> +        */
> +
> +       if (priv->nr_idcs)
> +               return;
> +
> +       reg_off =3D APLIC_CLRIP_BASE + ((d->hwirq / APLIC_IRQBITS_PER_REG=
) * 4);
> +       reg_mask =3D BIT(d->hwirq % APLIC_IRQBITS_PER_REG);
> +       switch (irqd_get_trigger_type(d)) {
> +       case IRQ_TYPE_LEVEL_LOW:
> +               if (!(readl(priv->regs + reg_off) & reg_mask))
> +                       writel(d->hwirq, priv->regs + APLIC_SETIPNUM_LE);
> +               break;
> +       case IRQ_TYPE_LEVEL_HIGH:
> +               if (readl(priv->regs + reg_off) & reg_mask)
> +                       writel(d->hwirq, priv->regs + APLIC_SETIPNUM_LE);
> +               break;
> +       }
> +}
> +
> +#ifdef CONFIG_SMP
> +static int aplic_set_affinity(struct irq_data *d,
> +                             const struct cpumask *mask_val, bool force)
> +{
> +       struct aplic_priv *priv =3D 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 =3D cpumask_first(&amask);
> +       else
> +               cpu =3D cpumask_any_and(&amask, cpu_online_mask);
> +
> +       if (cpu >=3D nr_cpu_ids)
> +               return -EINVAL;
> +
> +       idc =3D per_cpu_ptr(&aplic_idcs, cpu);
> +       target =3D priv->regs + APLIC_TARGET_BASE;
> +       target +=3D (d->hwirq - 1) * sizeof(u32);
> +       val =3D idc->hart_index & APLIC_TARGET_HART_IDX_MASK;
> +       val <<=3D APLIC_TARGET_HART_IDX_SHIFT;
> +       val |=3D 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 =3D {
> +       .name           =3D "RISC-V APLIC",
> +       .irq_mask       =3D aplic_irq_mask,
> +       .irq_unmask     =3D aplic_irq_unmask,
> +       .irq_set_type   =3D aplic_set_type,
> +       .irq_eoi        =3D aplic_irq_eoi,
> +#ifdef CONFIG_SMP
> +       .irq_set_affinity =3D aplic_set_affinity,
> +#endif
> +       .flags          =3D IRQCHIP_SET_TYPE_MASKED |
> +                         IRQCHIP_SKIP_SET_WAKE |
> +                         IRQCHIP_MASK_ON_SUSPEND,
> +};
> +
> +static int aplic_irqdomain_translate(struct irq_fwspec *fwspec,
> +                                    u32 gsi_base,
> +                                    unsigned long *hwirq,
> +                                    unsigned int *type)
> +{
> +       if (WARN_ON(fwspec->param_count < 2))
> +               return -EINVAL;
> +       if (WARN_ON(!fwspec->param[0]))
> +               return -EINVAL;
> +
> +       /* For DT, gsi_base is always zero. */
> +       *hwirq =3D fwspec->param[0] - gsi_base;
> +       *type =3D fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> +
> +       WARN_ON(*type =3D=3D IRQ_TYPE_NONE);
> +
> +       return 0;
> +}
> +
> +static int aplic_irqdomain_msi_translate(struct irq_domain *d,
> +                                        struct irq_fwspec *fwspec,
> +                                        unsigned long *hwirq,
> +                                        unsigned int *type)
> +{
> +       struct aplic_priv *priv =3D platform_msi_get_host_data(d);
> +
> +       return aplic_irqdomain_translate(fwspec, priv->gsi_base, hwirq, t=
ype);
> +}
> +
> +static int aplic_irqdomain_msi_alloc(struct irq_domain *domain,
> +                                    unsigned int virq, unsigned int nr_i=
rqs,
> +                                    void *arg)
> +{
> +       int i, ret;
> +       unsigned int type;
> +       irq_hw_number_t hwirq;
> +       struct irq_fwspec *fwspec =3D arg;
> +       struct aplic_priv *priv =3D platform_msi_get_host_data(domain);
> +
> +       ret =3D aplic_irqdomain_translate(fwspec, priv->gsi_base, &hwirq,=
 &type);
> +       if (ret)
> +               return ret;
> +
> +       ret =3D platform_msi_device_domain_alloc(domain, virq, nr_irqs);
> +       if (ret)
> +               return ret;
> +
> +       for (i =3D 0; i < nr_irqs; i++) {
> +               irq_domain_set_info(domain, virq + i, hwirq + i,
> +                                   &aplic_chip, priv, handle_fasteoi_irq=
,
> +                                   NULL, NULL);
> +               /*
> +                * APLIC does not implement irq_disable() so Linux interr=
upt
> +                * subsystem will take a lazy approach for disabling an A=
PLIC
> +                * interrupt. This means APLIC interrupts are left unmask=
ed
> +                * upon system suspend and interrupts are not processed
> +                * immediately upon system wake up. To tackle this, we di=
sable
> +                * the lazy approach for all APLIC interrupts.
> +                */
> +               irq_set_status_flags(virq + i, IRQ_DISABLE_UNLAZY);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct irq_domain_ops aplic_irqdomain_msi_ops =3D {
> +       .translate      =3D aplic_irqdomain_msi_translate,
> +       .alloc          =3D aplic_irqdomain_msi_alloc,
> +       .free           =3D platform_msi_device_domain_free,
> +};
> +
> +static int aplic_irqdomain_idc_translate(struct irq_domain *d,
> +                                        struct irq_fwspec *fwspec,
> +                                        unsigned long *hwirq,
> +                                        unsigned int *type)
> +{
> +       struct aplic_priv *priv =3D d->host_data;
> +
> +       return aplic_irqdomain_translate(fwspec, priv->gsi_base, hwirq, t=
ype);
> +}
> +
> +static int aplic_irqdomain_idc_alloc(struct irq_domain *domain,
> +                                    unsigned int virq, unsigned int nr_i=
rqs,
> +                                    void *arg)
> +{
> +       int i, ret;
> +       unsigned int type;
> +       irq_hw_number_t hwirq;
> +       struct irq_fwspec *fwspec =3D arg;
> +       struct aplic_priv *priv =3D domain->host_data;
> +
> +       ret =3D aplic_irqdomain_translate(fwspec, priv->gsi_base, &hwirq,=
 &type);
> +       if (ret)
> +               return ret;
> +
> +       for (i =3D 0; i < nr_irqs; i++) {
> +               irq_domain_set_info(domain, virq + i, hwirq + i,
> +                                   &aplic_chip, priv, handle_fasteoi_irq=
,
> +                                   NULL, NULL);
> +               irq_set_affinity(virq + i, &priv->lmask);
> +               /* See the reason described in aplic_irqdomain_msi_alloc(=
) */
> +               irq_set_status_flags(virq + i, IRQ_DISABLE_UNLAZY);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct irq_domain_ops aplic_irqdomain_idc_ops =3D {
> +       .translate      =3D aplic_irqdomain_idc_translate,
> +       .alloc          =3D aplic_irqdomain_idc_alloc,
> +       .free           =3D irq_domain_free_irqs_top,
> +};
> +
> +static void aplic_init_hw_irqs(struct aplic_priv *priv)
> +{
> +       int i;
> +
> +       /* Disable all interrupts */
> +       for (i =3D 0; i <=3D priv->nr_irqs; i +=3D 32)
> +               writel(-1U, priv->regs + APLIC_CLRIE_BASE +
> +                           (i / 32) * sizeof(u32));
> +
> +       /* Set interrupt type and default priority for all interrupts */
> +       for (i =3D 1; i <=3D 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 =3D priv->msicfg.base_ppn;
> +               valH =3D (priv->msicfg.base_ppn >> 32) &
> +                       APLIC_xMSICFGADDRH_BAPPN_MASK;
> +               valH |=3D (priv->msicfg.lhxw & APLIC_xMSICFGADDRH_LHXW_MA=
SK)
> +                       << APLIC_xMSICFGADDRH_LHXW_SHIFT;
> +               valH |=3D (priv->msicfg.hhxw & APLIC_xMSICFGADDRH_HHXW_MA=
SK)
> +                       << APLIC_xMSICFGADDRH_HHXW_SHIFT;
> +               valH |=3D (priv->msicfg.lhxs & APLIC_xMSICFGADDRH_LHXS_MA=
SK)
> +                       << APLIC_xMSICFGADDRH_LHXS_SHIFT;
> +               valH |=3D (priv->msicfg.hhxs & APLIC_xMSICFGADDRH_HHXS_MA=
SK)
> +                       << APLIC_xMSICFGADDRH_HHXS_SHIFT;
> +               writel(val, priv->regs + APLIC_xMSICFGADDR);
> +               writel(valH, priv->regs + APLIC_xMSICFGADDRH);
> +       }
> +#endif
> +
> +       /* Setup APLIC domaincfg register */
> +       val =3D readl(priv->regs + APLIC_DOMAINCFG);
> +       val |=3D APLIC_DOMAINCFG_IE;
> +       if (!priv->nr_idcs)
> +               val |=3D APLIC_DOMAINCFG_DM;
> +       writel(val, priv->regs + APLIC_DOMAINCFG);
> +       if (readl(priv->regs + APLIC_DOMAINCFG) !=3D val)
> +               pr_warn("%pfwP: unable to write 0x%x in domaincfg\n",
> +                       priv->fwnode, val);
> +}
> +
> +static void aplic_msi_write_msg(struct msi_desc *desc, struct msi_msg *m=
sg)
> +{
> +       unsigned int group_index, hart_index, guest_index, val;
> +       struct irq_data *d =3D irq_get_irq_data(desc->irq);
> +       struct aplic_priv *priv =3D irq_data_get_irq_chip_data(d);
> +       struct aplic_msicfg *mc =3D &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 =3D priv->regs + APLIC_TARGET_BASE;
> +               target +=3D (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 =3D (((u64)msg->address_hi) << 32) | msg->address_lo;
> +       tppn =3D msg_addr >> APLIC_xMSICFGADDR_PPN_SHIFT;
> +
> +       /* Compute target HART Base PPN */
> +       tbppn =3D tppn;
> +       tbppn &=3D ~APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> +       tbppn &=3D ~APLIC_xMSICFGADDR_PPN_LHX(mc->lhxw, mc->lhxs);
> +       tbppn &=3D ~APLIC_xMSICFGADDR_PPN_HHX(mc->hhxw, mc->hhxs);
> +       WARN_ON(tbppn !=3D mc->base_ppn);
> +
> +       /* Compute target group and hart indexes */
> +       group_index =3D (tppn >> APLIC_xMSICFGADDR_PPN_HHX_SHIFT(mc->hhxs=
)) &
> +                    APLIC_xMSICFGADDR_PPN_HHX_MASK(mc->hhxw);
> +       hart_index =3D (tppn >> APLIC_xMSICFGADDR_PPN_LHX_SHIFT(mc->lhxs)=
) &
> +                    APLIC_xMSICFGADDR_PPN_LHX_MASK(mc->lhxw);
> +       hart_index |=3D (group_index << mc->lhxw);
> +       WARN_ON(hart_index > APLIC_TARGET_HART_IDX_MASK);
> +
> +       /* Compute target guest index */
> +       guest_index =3D tppn & APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> +       WARN_ON(guest_index > APLIC_TARGET_GUEST_IDX_MASK);
> +
> +       /* Update IRQ TARGET register */
> +       target =3D priv->regs + APLIC_TARGET_BASE;
> +       target +=3D (d->hwirq - 1) * sizeof(u32);
> +       val =3D (hart_index & APLIC_TARGET_HART_IDX_MASK)
> +                               << APLIC_TARGET_HART_IDX_SHIFT;
> +       val |=3D (guest_index & APLIC_TARGET_GUEST_IDX_MASK)
> +                               << APLIC_TARGET_GUEST_IDX_SHIFT;
> +       val |=3D (msg->data & APLIC_TARGET_EIID_MASK);
> +       writel(val, target);
> +}
> +
> +static int aplic_setup_msi(struct aplic_priv *priv)
> +{
> +       struct aplic_msicfg *mc =3D &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 =3D imsic_get_global_config();
> +       if (!imsic_global) {
> +               pr_err("%pfwP: IMSIC global config not found\n",
> +                       priv->fwnode);
> +               return -ENODEV;
> +       }
> +
> +       /* Find number of guest index bits (LHXS) */
> +       mc->lhxs =3D imsic_global->guest_index_bits;
> +       if (APLIC_xMSICFGADDRH_LHXS_MASK < mc->lhxs) {
> +               pr_err("%pfwP: IMSIC guest index bits big for APLIC LHXS\=
n",
> +                       priv->fwnode);
> +               return -EINVAL;
> +       }
> +
> +       /* Find number of HART index bits (LHXW) */
> +       mc->lhxw =3D imsic_global->hart_index_bits;
> +       if (APLIC_xMSICFGADDRH_LHXW_MASK < mc->lhxw) {
> +               pr_err("%pfwP: IMSIC hart index bits big for APLIC LHXW\n=
",
> +                       priv->fwnode);
> +               return -EINVAL;
> +       }
> +
> +       /* Find number of group index bits (HHXW) */
> +       mc->hhxw =3D imsic_global->group_index_bits;
> +       if (APLIC_xMSICFGADDRH_HHXW_MASK < mc->hhxw) {
> +               pr_err("%pfwP: IMSIC group index bits big for APLIC HHXW\=
n",
> +                       priv->fwnode);
> +               return -EINVAL;
> +       }
> +
> +       /* Find first bit position of group index (HHXS) */
> +       mc->hhxs =3D imsic_global->group_index_shift;
> +       if (mc->hhxs < (2 * APLIC_xMSICFGADDR_PPN_SHIFT)) {
> +               pr_err("%pfwP: IMSIC group index shift should be >=3D %d\=
n",
> +                       priv->fwnode, (2 * APLIC_xMSICFGADDR_PPN_SHIFT));
> +               return -EINVAL;
> +       }
> +       mc->hhxs -=3D (2 * APLIC_xMSICFGADDR_PPN_SHIFT);
> +       if (APLIC_xMSICFGADDRH_HHXS_MASK < mc->hhxs) {
> +               pr_err("%pfwP: IMSIC group index shift big for APLIC HHXS=
\n",
> +                       priv->fwnode);
> +               return -EINVAL;
> +       }
> +
> +       /* Compute PPN base */
> +       mc->base_ppn =3D imsic_global->base_addr >> APLIC_xMSICFGADDR_PPN=
_SHIFT;
> +       mc->base_ppn &=3D ~APLIC_xMSICFGADDR_PPN_HART(mc->lhxs);
> +       mc->base_ppn &=3D ~APLIC_xMSICFGADDR_PPN_LHX(mc->lhxw, mc->lhxs);
> +       mc->base_ppn &=3D ~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 =3D this_cpu_ptr(&aplic_idcs);
> +       struct irq_chip *chip =3D irq_desc_get_chip(desc);
> +       irq_hw_number_t hw_irq;
> +       int irq;
> +
> +       chained_irq_enter(chip, desc);
> +
> +       while ((hw_irq =3D readl(idc->regs + APLIC_IDC_CLAIMI))) {
> +               hw_irq =3D hw_irq >> APLIC_IDC_TOPI_ID_SHIFT;
> +               irq =3D irq_find_mapping(idc->priv->irqdomain, hw_irq);
> +
> +               if (unlikely(irq <=3D 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 =3D (en) ? APLIC_ENABLE_IDELIVERY : APLIC_DISABLE_IDELIVER=
Y;
> +       u32 th =3D (en) ? APLIC_ENABLE_ITHRESHOLD : APLIC_DISABLE_ITHRESH=
OLD;
> +
> +       /* 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_i=
rq));
> +
> +       return 0;
> +}
> +
> +static int aplic_setup_idc(struct aplic_priv *priv)
> +{
> +       int i, j, rc, cpu, setup_count =3D 0;
> +       struct fwnode_reference_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 =3D 0; i < priv->nr_idcs; i++) {
> +               rc =3D fwnode_property_get_reference_args(priv->fwnode,
> +                               "interrupts-extended", "#interrupt-cells"=
,
> +                               0, i, &parent);
> +               if (rc) {
> +                       pr_warn("%pfwP: parent irq for IDC%d not found\n"=
,
> +                               priv->fwnode, i);
> +                       continue;
> +               }
> +
> +               /*
> +                * Skip interrupts other than external interrupts for
> +                * current privilege level.
> +                */
> +               if (parent.args[0] !=3D RV_IRQ_EXT)
> +                       continue;
> +
> +               rc =3D riscv_fw_parent_hartid(parent.fwnode, &hartid);
> +               if (rc) {
> +                       pr_warn("%pfwP: invalid hartid for IDC%d\n",
> +                               priv->fwnode, i);
> +                       continue;
> +               }
> +
> +               cpu =3D riscv_hartid_to_cpuid(hartid);
> +               if (cpu < 0) {
> +                       pr_warn("%pfwP: invalid cpuid for IDC%d\n",
> +                               priv->fwnode, i);
> +                       continue;
> +               }
> +
> +               cpumask_set_cpu(cpu, &priv->lmask);
> +
> +               idc =3D per_cpu_ptr(&aplic_idcs, cpu);
> +               idc->hart_index =3D i;
> +               idc->regs =3D priv->regs + APLIC_IDC_BASE + i * APLIC_IDC=
_SIZE;
> +               idc->priv =3D priv;
> +
> +               aplic_idc_set_delivery(idc, true);
> +
> +               /*
> +                * Boot cpu might not have APLIC hart_index =3D 0 so chec=
k
> +                * and update target registers of all interrupts.
> +                */
> +               if (cpu =3D=3D smp_processor_id() && idc->hart_index) {
> +                       val =3D idc->hart_index & APLIC_TARGET_HART_IDX_M=
ASK;
> +                       val <<=3D APLIC_TARGET_HART_IDX_SHIFT;
> +                       val |=3D APLIC_DEFAULT_PRIORITY;
> +                       for (j =3D 1; j <=3D priv->nr_irqs; j++)
> +                               writel(val, priv->regs + APLIC_TARGET_BAS=
E +
> +                                           (j - 1) * sizeof(u32));
> +               }
> +
> +               setup_count++;
> +       }
> +
> +       /* Find parent domain and register chained handler */
> +       domain =3D irq_find_matching_fwnode(riscv_get_intc_hwnode(),
> +                                         DOMAIN_BUS_ANY);
> +       if (!aplic_idc_parent_irq && domain) {
> +               aplic_idc_parent_irq =3D irq_create_mapping(domain, RV_IR=
Q_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 fwnode_handle *fwnode =3D pdev->dev.fwnode;
> +       struct fwnode_reference_args parent;
> +       struct aplic_priv *priv;
> +       struct resource *res;
> +       phys_addr_t pa;
> +       int rc;
> +
> +       priv =3D devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;
> +       priv->fwnode =3D fwnode;
> +
> +       /* Map the MMIO registers */
> +       res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res) {
> +               pr_err("%pfwP: failed to get MMIO resource\n", fwnode);
> +               return -EINVAL;
> +       }
> +       priv->regs =3D devm_ioremap(&pdev->dev, res->start, resource_size=
(res));
> +       if (!priv->regs) {
> +               pr_err("%pfwP: failed map MMIO registers\n", fwnode);
> +               return -ENOMEM;
> +       }
> +
> +       /*
> +        * Find out GSI base number
> +        *
> +        * Note: DT does not define "riscv,gsi-base" property so GSI
> +        * base is always zero for DT.
> +        */
> +       rc =3D fwnode_property_read_u32_array(fwnode, "riscv,gsi-base",
> +                                           &priv->gsi_base, 1);
> +       if (rc)
> +               priv->gsi_base =3D 0;
> +
> +       /* Find out number of interrupt sources */
> +       rc =3D fwnode_property_read_u32_array(fwnode, "riscv,num-sources"=
,
> +                                           &priv->nr_irqs, 1);
> +       if (rc) {
> +               pr_err("%pfwP: failed to get number of interrupt sources\=
n",
> +                       fwnode);
> +               return rc;
> +       }
> +
> +       /* Setup initial state APLIC interrupts */
> +       aplic_init_hw_irqs(priv);
> +
> +       /*
> +        * Find out number of IDCs based on parent interrupts
> +        *
> +        * If "msi-parent" property is present then we ignore the
> +        * APLIC IDCs which forces the APLIC driver to use MSI mode.
> +        */
> +       if (!fwnode_property_present(fwnode, "msi-parent")) {
> +               while (!fwnode_property_get_reference_args(fwnode,
> +                               "interrupts-extended", "#interrupt-cells"=
,
> +                               0, priv->nr_idcs, &parent))
> +                       priv->nr_idcs++;
> +       }
> +
> +       /* Setup IDCs or MSIs based on number of IDCs */
> +       if (priv->nr_idcs)
> +               rc =3D aplic_setup_idc(priv);
> +       else
> +               rc =3D aplic_setup_msi(priv);
> +       if (rc) {
> +               pr_err("%pfwP: failed setup %s\n",
> +                       fwnode, priv->nr_idcs ? "IDCs" : "MSIs");
> +               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 =3D irq_domain_create_linear(
> +                                               priv->fwnode,
> +                                               priv->nr_irqs + 1,
> +                                               &aplic_irqdomain_idc_ops,
> +                                               priv);
> +       else
> +               priv->irqdomain =3D platform_msi_create_device_domain(
> +                                               &pdev->dev,
> +                                               priv->nr_irqs + 1,
> +                                               aplic_msi_write_msg,
> +                                               &aplic_irqdomain_msi_ops,
> +                                               priv);
> +       if (!priv->irqdomain) {
> +               pr_err("%pfwP: failed to add irq domain\n", priv->fwnode)=
;
> +               return -ENOMEM;
> +       }
> +
> +       /* Advertise the interrupt controller */
> +       if (priv->nr_idcs) {
> +               pr_info("%pfwP: %d interrupts directly connected to %d CP=
Us\n",
> +                       priv->fwnode, priv->nr_irqs, priv->nr_idcs);
> +       } else {
> +               pa =3D priv->msicfg.base_ppn << APLIC_xMSICFGADDR_PPN_SHI=
FT;
> +               pr_info("%pfwP: %d interrupts forwared to MSI base %pa\n"=
,
> +                       priv->fwnode, priv->nr_irqs, &pa);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id aplic_match[] =3D {
> +       { .compatible =3D "riscv,aplic" },
> +       {}
> +};
> +
> +static struct platform_driver aplic_driver =3D {
> +       .driver =3D {
> +               .name           =3D "riscv-aplic",
> +               .of_match_table =3D aplic_match,
> +       },
> +       .probe =3D aplic_probe,
> +};
> +builtin_platform_driver(aplic_driver);
> +
> +static int __init aplic_dt_init(struct device_node *node,
> +                               struct device_node *parent)
> +{
> +       /*
> +        * The APLIC platform driver needs to be probed early
> +        * so for device tree:
> +        *
> +        * 1) Set the FWNODE_FLAG_BEST_EFFORT flag in fwnode which
> +        *    provides a hint to the device driver core to probe the
> +        *    platform driver early.
> +        * 2) Clear the OF_POPULATED flag in device_node because
> +        *    of_irq_init() sets it which prevents creation of
> +        *    platform device.
> +        */
> +       node->fwnode.flags |=3D FWNODE_FLAG_BEST_EFFORT;

NACK. You are blindly plastering flags without trying to understand
the real issue and fixing this correctly.

> +       of_node_clear_flag(node, OF_POPULATED);
> +       return 0;
> +}
> +IRQCHIP_DECLARE(riscv_aplic, "riscv,aplic", aplic_dt_init);

This macro pretty much skips the entire driver core framework to probe
and calls init and you are supposed to initialize the device when the
init function is called.

If you want your device/driver to follow the proper platform driver
path (which is recommended), then you need to use the
IRQCHIP_PLATFORM_DRIVER_BEGIN() and related macros. Grep for plenty of exam=
ples.

I offered to help you debug this issue and I asked for a dts file that
corresponds to a board you are testing this on and seeing an issue.
But you haven't answered my question [1] and are pointing to some
random commit and blaming it. That commit has no impact on any
existing devices/drivers.

Hi Marc,

Please consider this patch Nacked as long as FWNODE_FLAG_BEST_EFFORT
is used or until Anup actually works with us to debug the real issue.

-Saravana
[1] - https://lore.kernel.org/lkml/CAAhSdy2p6K70fc2yZLPdVGqEq61Y8F7WVT2J8st=
5mQrzBi4WHg@mail.gmail.com/


> diff --git a/include/linux/irqchip/riscv-aplic.h b/include/linux/irqchip/=
riscv-aplic.h
> new file mode 100644
> index 000000000000..97e198ea0109
> --- /dev/null
> +++ b/include/linux/irqchip/riscv-aplic.h
> @@ -0,0 +1,119 @@
> +/* 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_IRQBITS_PER_REG          32
> +
> +#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
>