linux-kernel - Re: [PATCH 4/6] ARCv2: IRQ: Remove option for setting number of interrupts

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Date:   Mon, 30 Jan 2017 10:59:29 -0800
From:   Vineet Gupta <Vineet.Gupta1@...opsys.com>
To:     Yuriy Kolerov <yuriy.kolerov@...opsys.com>,
        <linux-snps-arc@...ts.infradead.org>
CC:     <marc.zyngier@....com>, <Vineet.Gupta1@...opsys.com>,
        <Alexey.Brodkin@...opsys.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/6] ARCv2: IRQ: Remove option for setting number of
 interrupts

On 01/27/2017 04:01 PM, Yuriy Kolerov wrote:
> When you set a value of ARC_NUMBER_OF_INTERRUPTS option
> it affects only a size of the interrupts table but macros
> for number of virtual interrupts (NR_IRQS) and for number
> of hardware interrupts (NR_CPU_IRQS) remain unchanged.
> Moreover usage of ARC_NUMBER_OF_INTERRUPTS is bad for
> portability since it is not possible to change size
> of the interrupts table after linkage.
> 
> This patch makes these changes in IRQ subsystem:
> 
>   * NR_CPU_IRQS defines a maximum number of hardware interrupts.
>   * Remove ARC_NUMBER_OF_INTERRUPTS option and create interrupts
>     table for all possible hardware interrupts.
>   * Increase a maximum number of virtual IRQs to 512. ARCv2 can
>     support 240 interrupts in the core interrupts controllers
>     and 128 interrupts in IDU. Thus 512 virtual IRQs must be
>     enough for most configurations of boards.
> 
> Signed-off-by: Yuriy Kolerov <yuriy.kolerov@...opsys.com>

LGTM.

Thx,
-Vineet

> ---
>  arch/arc/Kconfig              | 11 -----------
>  arch/arc/include/asm/irq.h    | 28 +++++++++++++++++++++++++---
>  arch/arc/kernel/entry-arcv2.S |  3 ++-
>  3 files changed, 27 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
> index 283099c..ba15cb8 100644
> --- a/arch/arc/Kconfig
> +++ b/arch/arc/Kconfig
> @@ -412,17 +412,6 @@ config ARC_HAS_DIV_REM
>  	bool "Insn: div, divu, rem, remu"
>  	default y
>  
> -config ARC_NUMBER_OF_INTERRUPTS
> -	int "Number of interrupts"
> -	range 8 240
> -	default 32
> -	help
> -	  This defines the number of interrupts on the ARCv2HS core.
> -	  It affects the size of vector table.
> -	  The initial 8 IRQs are fixed (Timer, ICI etc) and although configurable
> -	  in hardware, it keep things simple for Linux to assume they are always
> -	  present.
> -
>  endif	# ISA_ARCV2
>  
>  endmenu   # "ARC CPU Configuration"
> diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h
> index e61ad30..dfa09e3 100644
> --- a/arch/arc/include/asm/irq.h
> +++ b/arch/arc/include/asm/irq.h
> @@ -9,19 +9,41 @@
>  #ifndef __ASM_ARC_IRQ_H
>  #define __ASM_ARC_IRQ_H
>  
> -#define NR_CPU_IRQS	32  /* number of interrupt lines of ARC770 CPU */
> -#define NR_IRQS		128 /* allow some CPU external IRQ handling */
> +#ifdef CONFIG_ISA_ARCV2
> +
> +/*
> + * A maximum number of supported interrupts in the core interrupt controller.
> + * This number is not equal to the maximum interrupt number (256) because
> + * first 16 lines are reserved for exceptions and are not configurable.
> + */
> +#define NR_CPU_IRQS	240
> +
> +/*
> + * ARCv2 can support 240 interrupts in the core interrupts controllers and
> + * 128 interrupts in IDU. Thus 512 virtual IRQs must be enough for most
> + * configurations of boards.
> + */
> +#define NR_IRQS		512
>  
>  /* Platform Independent IRQs */
> -#ifdef CONFIG_ISA_ARCV2
>  #define IPI_IRQ		19
>  #define SOFTIRQ_IRQ	21
>  #define FIRST_EXT_IRQ	24
> +
> +#else
> +
> +#define NR_CPU_IRQS	32  /* number of interrupt lines of ARC770 CPU */
> +#define NR_IRQS		128 /* allow some CPU external IRQ handling */
> +
>  #endif
>  
> +#ifndef __ASSEMBLY__
> +
>  #include <linux/interrupt.h>
>  #include <asm-generic/irq.h>
>  
>  extern void arc_init_IRQ(void);
>  
>  #endif
> +
> +#endif
> diff --git a/arch/arc/kernel/entry-arcv2.S b/arch/arc/kernel/entry-arcv2.S
> index 0b6388a..f22101e 100644
> --- a/arch/arc/kernel/entry-arcv2.S
> +++ b/arch/arc/kernel/entry-arcv2.S
> @@ -13,6 +13,7 @@
>  #include <asm/errno.h>
>  #include <asm/arcregs.h>
>  #include <asm/irqflags.h>
> +#include <asm/irq.h>
>  
>  	.cpu HS
>  
> @@ -52,7 +53,7 @@ VECTOR	handle_interrupt	; unused
>  VECTOR	handle_interrupt	; (23) unused
>  # End of fixed IRQs
>  
> -.rept CONFIG_ARC_NUMBER_OF_INTERRUPTS - 8
> +.rept NR_CPU_IRQS - 8
>  	VECTOR	handle_interrupt
>  .endr
>  
>