Re: [PATCH v5 03/16] irqchip/riscv-intc: Introduce Andes hart-level interrupt controller

[Anup Patel]

On Wed, Dec 13, 2023 at 12:35 PM Yu Chien Peter Lin
<peterlin@xxxxxxxxxxxxx> 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.
>
> 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 private data.
>
> Andes hart-level interrupt controller requires the "andestech,cpu-intc"
> compatible string to be present in interrupt-controller of cpu node.
> 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@xxxxxxxxxxxxx>
> Reviewed-by: Charles Ci-Jyun Wu <dminus@xxxxxxxxxxxxx>
> Reviewed-by: Leo Yu-Chi Liang <ycliang@xxxxxxxxxxxxx>
> ---
> 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
>
> [1] https://patchwork.kernel.org/project/linux-riscv/patch/20231019135723.3657156-1-peterlin@xxxxxxxxxxxxx/
> ---
>  drivers/irqchip/irq-riscv-intc.c | 53 ++++++++++++++++++++++++++++----
>  include/linux/soc/andes/irq.h    | 17 ++++++++++
>  2 files changed, 64 insertions(+), 6 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 2fdd40f2a791..0b6bf3fb1dba 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;
>
> @@ -46,6 +47,31 @@ 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 - ANDES_SLI_CAUSE_BASE);
> +
> +       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 - ANDES_SLI_CAUSE_BASE);
> +
> +       if (d->hwirq < ANDES_SLI_CAUSE_BASE)
> +               csr_set(CSR_IE, mask);
> +       else
> +               csr_set(ANDES_CSR_SLIE, mask);

Clearly, Andes does not have any CSR for:
XLEN <= local interrupt <ANDES_SLI_CAUSE_BASE
and
ANDES_SLI_CAUSE_BASE + XLEN <= local interrupt

Regards,
Anup

> +}
> +
>  static void riscv_intc_irq_eoi(struct irq_data *d)
>  {
>         /*
> @@ -69,11 +95,20 @@ 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,
> +       irq_domain_set_info(d, irq, hwirq, chip, NULL,
>                             handle_percpu_devid_irq, NULL, NULL);
>
>         return 0;
> @@ -112,11 +147,12 @@ 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;
> @@ -136,8 +172,9 @@ 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 = &riscv_intc_chip;
>         unsigned long hartid;
> +       int rc;
>
>         rc = riscv_of_parent_hartid(node, &hartid);
>         if (rc < 0) {
> @@ -162,10 +199,14 @@ static int __init riscv_intc_init(struct device_node *node,
>                 return 0;
>         }
>
> -       return riscv_intc_init_common(of_node_to_fwnode(node));
> +       if (of_device_is_compatible(node, "andestech,cpu-intc"))
> +               chip = &andes_intc_chip;
> +
> +       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
>
> @@ -192,7 +233,7 @@ 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..f03e68fea261
> --- /dev/null
> +++ b/include/linux/soc/andes/irq.h
> @@ -0,0 +1,17 @@
> +/* 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_PMU               18
> +#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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