Re: [PATCH v7 03/16] irqchip/riscv-intc: Introduce Andes hart-level interrupt controller

[Anup Patel <anup@brainfault.org>]

On Wed, Jan 10, 2024 at 1:10 PM Yu Chien Peter Lin
<peterlin@andestech.com> wrote:
>
> Add support for the Andes hart-level interrupt controller. This
> controller provides interrupt mask/unmask functions to access the
> custom register (SLIE) where the non-standard S-mode local interrupt
> enable bits are located. The base of custom interrupt number is set
> to 256.
>
> To share the riscv_intc_domain_map() with the generic RISC-V INTC and
> ACPI, add a chip parameter to riscv_intc_init_common(), so it can be
> passed to the irq_domain_set_info() as a private data.
>
> Andes hart-level interrupt controller requires the "andestech,cpu-intc"
> compatible string to be present in interrupt-controller of cpu node to
> enable the use of custom local interrupt source.
> e.g.,
>
>   cpu0: cpu@0 {
>       compatible = "andestech,ax45mp", "riscv";
>       ...
>       cpu0-intc: interrupt-controller {
>           #interrupt-cells = <0x01>;
>           compatible = "andestech,cpu-intc", "riscv,cpu-intc";
>           interrupt-controller;
>       };
>   };
>
> Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
> Reviewed-by: Randolph <randolph@andestech.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
> Changes v1 -> v2:
>   - New patch
> Changes v2 -> v3:
>   - Return -ENXIO if no valid compatible INTC found
>   - Allow falling back to generic RISC-V INTC
> Changes v3 -> v4: (Suggested by Thomas [1])
>   - Add comment to andes irq chip function
>   - Refine code flow to share with generic RISC-V INTC and ACPI
>   - Move Andes specific definitions to include/linux/soc/andes/irq.h
> Changes v4 -> v5: (Suggested by Thomas)
>   - Fix commit message
>   - Subtract ANDES_SLI_CAUSE_BASE from d->hwirq to calculate the value of mask
>   - Do not set chip_data to the chip itself with irq_domain_set_info()
>   - Follow reverse fir tree order variable declarations
> Changes v5 -> v6:
>   - To follow the naming on datasheet, rename ANDES_RV_IRQ_PMU to ANDES_RV_IRQ_PMOVI
>   - Initialize the riscv_intc_* global variables for Andes INTC (Suggested by Anup)
>   - Use BITS_PER_LONG to compute the bit mask of SIE/SLIE as they are 64-bit registers (32-bit for RV32)
> Changes v6 -> v7:
>   - No change
>
> [1] https://patchwork.kernel.org/project/linux-riscv/patch/20231019135723.3657156-1-peterlin@andestech.com/
> ---
>  drivers/irqchip/irq-riscv-intc.c | 66 +++++++++++++++++++++++++++-----
>  include/linux/soc/andes/irq.h    | 18 +++++++++
>  2 files changed, 74 insertions(+), 10 deletions(-)
>  create mode 100644 include/linux/soc/andes/irq.h
>
> diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
> index b13a16b164c9..7064857f1f1d 100644
> --- a/drivers/irqchip/irq-riscv-intc.c
> +++ b/drivers/irqchip/irq-riscv-intc.c
> @@ -17,6 +17,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/smp.h>
> +#include <linux/soc/andes/irq.h>
>
>  static struct irq_domain *intc_domain;
>  static unsigned int riscv_intc_nr_irqs __ro_after_init;
> @@ -49,6 +50,31 @@ static void riscv_intc_irq_unmask(struct irq_data *d)
>         csr_set(CSR_IE, BIT(d->hwirq));
>  }
>
> +static void andes_intc_irq_mask(struct irq_data *d)
> +{
> +       /*
> +        * Andes specific S-mode local interrupt causes (hwirq)
> +        * are defined as (256 + n) and controlled by n-th bit
> +        * of SLIE.
> +        */
> +       unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
> +
> +       if (d->hwirq < ANDES_SLI_CAUSE_BASE)
> +               csr_clear(CSR_IE, mask);
> +       else
> +               csr_clear(ANDES_CSR_SLIE, mask);
> +}
> +
> +static void andes_intc_irq_unmask(struct irq_data *d)
> +{
> +       unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
> +
> +       if (d->hwirq < ANDES_SLI_CAUSE_BASE)
> +               csr_set(CSR_IE, mask);
> +       else
> +               csr_set(ANDES_CSR_SLIE, mask);
> +}
> +
>  static void riscv_intc_irq_eoi(struct irq_data *d)
>  {
>         /*
> @@ -72,12 +98,21 @@ static struct irq_chip riscv_intc_chip = {
>         .irq_eoi = riscv_intc_irq_eoi,
>  };
>
> +static struct irq_chip andes_intc_chip = {
> +       .name           = "RISC-V INTC",
> +       .irq_mask       = andes_intc_irq_mask,
> +       .irq_unmask     = andes_intc_irq_unmask,
> +       .irq_eoi        = riscv_intc_irq_eoi,
> +};
> +
>  static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
>                                  irq_hw_number_t hwirq)
>  {
> +       struct irq_chip *chip = d->host_data;
> +
>         irq_set_percpu_devid(irq);
> -       irq_domain_set_info(d, irq, hwirq, &riscv_intc_chip, d->host_data,
> -                           handle_percpu_devid_irq, NULL, NULL);
> +       irq_domain_set_info(d, irq, hwirq, chip, NULL, handle_percpu_devid_irq,
> +                           NULL, NULL);
>
>         return 0;
>  }
> @@ -123,11 +158,12 @@ static struct fwnode_handle *riscv_intc_hwnode(void)
>         return intc_domain->fwnode;
>  }
>
> -static int __init riscv_intc_init_common(struct fwnode_handle *fn)
> +static int __init riscv_intc_init_common(struct fwnode_handle *fn,
> +                                        struct irq_chip *chip)
>  {
>         int rc;
>
> -       intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, NULL);
> +       intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, chip);
>         if (!intc_domain) {
>                 pr_err("unable to add IRQ domain\n");
>                 return -ENXIO;
> @@ -152,8 +188,9 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
>  static int __init riscv_intc_init(struct device_node *node,
>                                   struct device_node *parent)
>  {
> -       int rc;
> +       struct irq_chip *chip;
>         unsigned long hartid;
> +       int rc;
>
>         rc = riscv_of_parent_hartid(node, &hartid);
>         if (rc < 0) {
> @@ -178,14 +215,23 @@ static int __init riscv_intc_init(struct device_node *node,
>                 return 0;
>         }
>
> -       riscv_intc_nr_irqs = BITS_PER_LONG;
> -       riscv_intc_custom_base = riscv_intc_nr_irqs;
> -       riscv_intc_custom_nr_irqs = 0;
> +       if (of_device_is_compatible(node, "andestech,cpu-intc")) {
> +               riscv_intc_nr_irqs = BITS_PER_LONG;
> +               riscv_intc_custom_base = ANDES_SLI_CAUSE_BASE;
> +               riscv_intc_custom_nr_irqs = ANDES_RV_IRQ_LAST;
> +               chip = &andes_intc_chip;
> +       } else {
> +               riscv_intc_nr_irqs = BITS_PER_LONG;
> +               riscv_intc_custom_base = riscv_intc_nr_irqs;
> +               riscv_intc_custom_nr_irqs = 0;
> +               chip = &riscv_intc_chip;
> +       }
>
> -       return riscv_intc_init_common(of_node_to_fwnode(node));
> +       return riscv_intc_init_common(of_node_to_fwnode(node), chip);
>  }
>
>  IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);
> +IRQCHIP_DECLARE(andes, "andestech,cpu-intc", riscv_intc_init);
>
>  #ifdef CONFIG_ACPI
>
> @@ -212,7 +258,7 @@ static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
>                 return -ENOMEM;
>         }
>
> -       return riscv_intc_init_common(fn);
> +       return riscv_intc_init_common(fn, &riscv_intc_chip);
>  }
>
>  IRQCHIP_ACPI_DECLARE(riscv_intc, ACPI_MADT_TYPE_RINTC, NULL,
> diff --git a/include/linux/soc/andes/irq.h b/include/linux/soc/andes/irq.h
> new file mode 100644
> index 000000000000..edc3182d6e66
> --- /dev/null
> +++ b/include/linux/soc/andes/irq.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023 Andes Technology Corporation
> + */
> +#ifndef __ANDES_IRQ_H
> +#define __ANDES_IRQ_H
> +
> +/* Andes PMU irq number */
> +#define ANDES_RV_IRQ_PMOVI             18
> +#define ANDES_RV_IRQ_LAST              ANDES_RV_IRQ_PMOVI
> +#define ANDES_SLI_CAUSE_BASE           256
> +
> +/* Andes PMU related registers */
> +#define ANDES_CSR_SLIE                 0x9c4
> +#define ANDES_CSR_SLIP                 0x9c5
> +#define ANDES_CSR_SCOUNTEROF           0x9d4
> +
> +#endif /* __ANDES_IRQ_H */
> --
> 2.34.1
>

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