Re: [RESEND PATCH v2 03/33] ARM: davinci: select GENERIC_IRQ_MULTI_HANDLER

From: Marc Zyngier <marc.zyngier@arm.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>, Sekhar Nori <nsekhar@ti.com>,
	Kevin Hilman <khilman@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	David Lechner <david@lechnology.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [RESEND PATCH v2 03/33] ARM: davinci: select GENERIC_IRQ_MULTI_HANDLER
Date: Mon, 11 Feb 2019 12:50:21 +0000	[thread overview]
Message-ID: <0220fbc8-a73f-0f40-2b62-14bec019ac7c@arm.com> (raw)
In-Reply-To: <20190211122606.8662-4-brgl@bgdev.pl>

On 11/02/2019 12:25, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> In order to support SPARSE_IRQ we first need to make davinci use the
> generic irq handler for ARM. Translate the legacy assembly to C and
> put the irq handlers into their respective drivers (aintc and cp-intc).
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  arch/arm/Kconfig                              |  1 +
>  arch/arm/mach-davinci/cp_intc.c               | 28 +++++++++++++
>  .../mach-davinci/include/mach/entry-macro.S   | 39 -------------------
>  arch/arm/mach-davinci/irq.c                   | 23 +++++++++++
>  4 files changed, 52 insertions(+), 39 deletions(-)
>  delete mode 100644 arch/arm/mach-davinci/include/mach/entry-macro.S
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 664e918e2624..f7770fdcad68 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -589,6 +589,7 @@ config ARCH_DAVINCI
>  	select GENERIC_ALLOCATOR
>  	select GENERIC_CLOCKEVENTS
>  	select GENERIC_IRQ_CHIP
> +	select GENERIC_IRQ_MULTI_HANDLER
>  	select GPIOLIB
>  	select HAVE_IDE
>  	select PM_GENERIC_DOMAINS if PM
> diff --git a/arch/arm/mach-davinci/cp_intc.c b/arch/arm/mach-davinci/cp_intc.c
> index 67805ca74ff8..4a372add8cf9 100644
> --- a/arch/arm/mach-davinci/cp_intc.c
> +++ b/arch/arm/mach-davinci/cp_intc.c
> @@ -19,9 +19,13 @@
>  #include <linux/of_address.h>
>  #include <linux/of_irq.h>
>  
> +#include <asm/exception.h>
>  #include <mach/common.h>
>  #include "cp_intc.h"
>  
> +#define DAVINCI_CP_INTC_PRI_INDX_MASK		GENMASK(9, 0)
> +#define DAVINCI_CP_INTC_GPIR_NONE		BIT(31)
> +
>  static inline unsigned int cp_intc_read(unsigned offset)
>  {
>  	return __raw_readl(davinci_intc_base + offset);
> @@ -97,6 +101,28 @@ static struct irq_chip cp_intc_irq_chip = {
>  
>  static struct irq_domain *cp_intc_domain;
>  
> +static asmlinkage void __exception_irq_entry
> +cp_intc_handle_irq(struct pt_regs *regs)
> +{
> +	int gpir, irqnr, none;
> +
> +	/*
> +	 * The interrupt number is in first ten bits. The NONE field set to 1
> +	 * indicates a spurious irq.
> +	 */
> +
> +	gpir = cp_intc_read(CP_INTC_PRIO_IDX);
> +	irqnr = gpir & DAVINCI_CP_INTC_PRI_INDX_MASK;
> +	none = gpir & DAVINCI_CP_INTC_GPIR_NONE;
> +
> +	if (unlikely(none)) {
> +		pr_err_once("%s: spurious irq!\n", __func__);
> +		return;
> +	}
> +
> +	handle_domain_irq(cp_intc_domain, irqnr, regs);
> +}
> +
>  static int cp_intc_host_map(struct irq_domain *h, unsigned int virq,
>  			  irq_hw_number_t hw)
>  {
> @@ -196,6 +222,8 @@ int __init cp_intc_of_init(struct device_node *node, struct device_node *parent)
>  		return -EINVAL;
>  	}
>  
> +	set_handle_irq(cp_intc_handle_irq);
> +
>  	/* Enable global interrupt */
>  	cp_intc_write(1, CP_INTC_GLOBAL_ENABLE);
>  
> diff --git a/arch/arm/mach-davinci/include/mach/entry-macro.S b/arch/arm/mach-davinci/include/mach/entry-macro.S
> deleted file mode 100644
> index cf5f573eb5fd..000000000000
> --- a/arch/arm/mach-davinci/include/mach/entry-macro.S
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -/*
> - * Low-level IRQ helper macros for TI DaVinci-based platforms
> - *
> - * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
> - *
> - * 2007 (c) MontaVista Software, Inc. This file is licensed under
> - * the terms of the GNU General Public License version 2. This program
> - * is licensed "as is" without any warranty of any kind, whether express
> - * or implied.
> - */
> -#include <mach/irqs.h>
> -
> -		.macro  get_irqnr_preamble, base, tmp
> -		ldr \base, =davinci_intc_base
> -		ldr \base, [\base]
> -		.endm
> -
> -		.macro	get_irqnr_and_base, irqnr, irqstat, base, tmp
> -#if defined(CONFIG_AINTC) && defined(CONFIG_CP_INTC)
> -		ldr \tmp, =davinci_intc_type
> -		ldr \tmp, [\tmp]
> -		cmp \tmp, #DAVINCI_INTC_TYPE_CP_INTC
> -		beq 1001f
> -#endif
> -#if defined(CONFIG_AINTC)
> -		ldr \tmp, [\base, #0x14]
> -		movs \tmp, \tmp, lsr #2
> -		sub \irqnr, \tmp, #1
> -		b 1002f
> -#endif
> -#if defined(CONFIG_CP_INTC)
> -1001:		ldr \irqnr, [\base, #0x80] /* get irq number */
> -		mov \tmp, \irqnr, lsr #31
> -		and \irqnr, \irqnr, #0xff  /* irq is in bits 0-9 */
> -		and \tmp, \tmp, #0x1
> -		cmp \tmp, #0x1
> -#endif
> -1002:
> -		.endm
> diff --git a/arch/arm/mach-davinci/irq.c b/arch/arm/mach-davinci/irq.c
> index 07d8ef8037e4..3ce821a06e52 100644
> --- a/arch/arm/mach-davinci/irq.c
> +++ b/arch/arm/mach-davinci/irq.c
> @@ -29,11 +29,13 @@
>  #include <mach/cputype.h>
>  #include <mach/common.h>
>  #include <asm/mach/irq.h>
> +#include <asm/exception.h>
>  
>  #define FIQ_REG0_OFFSET		0x0000
>  #define FIQ_REG1_OFFSET		0x0004
>  #define IRQ_REG0_OFFSET		0x0008
>  #define IRQ_REG1_OFFSET		0x000C
> +#define IRQ_IRQENTRY_OFFSET	0x0014
>  #define IRQ_ENT_REG0_OFFSET	0x0018
>  #define IRQ_ENT_REG1_OFFSET	0x001C
>  #define IRQ_INCTL_REG_OFFSET	0x0020
> @@ -48,6 +50,11 @@ static inline void davinci_irq_writel(unsigned long value, int offset)
>  	__raw_writel(value, davinci_intc_base + offset);
>  }
>  
> +static inline unsigned long davinci_irq_readl(int offset)
> +{
> +	return __raw_readl(davinci_intc_base + offset);

I appreciate that you're converting assembly code dating from a while
back, but if we're going to do this correctly, I don't think we should
entertain the use of __raw_readl().

Surely the bus has a fixed endianness (and I'd assume it to be LE). Why
aren't you using readl_relaxed() instead, which will have the exact same
generated code with an LE kernel, and will do the right thing should you
run a BE kernel.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...