Re: [PATCH v2 1/9] RISC-V: Add AIA related CSR defines

From: Conor Dooley <conor@kernel.org>
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>,
	Atish Patra <atishp@atishpatra.org>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	Anup Patel <anup@brainfault.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: Re: [PATCH v2 1/9] RISC-V: Add AIA related CSR defines
Date: Wed, 4 Jan 2023 23:07:19 +0000	[thread overview]
Message-ID: <Y7YGp/7ufyRPhkwg@spud> (raw)
In-Reply-To: <20230103141409.772298-2-apatel@ventanamicro.com>

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Hey Anup!

On Tue, Jan 03, 2023 at 07:44:01PM +0530, Anup Patel wrote:
> The RISC-V AIA specification improves handling per-HART local interrupts
> in a backward compatible manner. This patch adds defines for new RISC-V
> AIA CSRs.
> 
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  arch/riscv/include/asm/csr.h | 92 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
> 
> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> index 0e571f6483d9..4e1356bad7b2 100644
> --- a/arch/riscv/include/asm/csr.h
> +++ b/arch/riscv/include/asm/csr.h
> @@ -73,7 +73,10 @@
>  #define IRQ_S_EXT		9
>  #define IRQ_VS_EXT		10
>  #define IRQ_M_EXT		11
> +#define IRQ_S_GEXT		12
>  #define IRQ_PMU_OVF		13
> +#define IRQ_LOCAL_MAX		(IRQ_PMU_OVF + 1)
> +#define IRQ_LOCAL_MASK		((_AC(1, UL) << IRQ_LOCAL_MAX) - 1)
>  
>  /* Exception causes */
>  #define EXC_INST_MISALIGNED	0
> @@ -156,6 +159,26 @@
>  				 (_AC(1, UL) << IRQ_S_TIMER) | \
>  				 (_AC(1, UL) << IRQ_S_EXT))
>  
> +/* AIA CSR bits */
> +#define TOPI_IID_SHIFT		16
> +#define TOPI_IID_MASK		0xfff
> +#define TOPI_IPRIO_MASK		0xff
> +#define TOPI_IPRIO_BITS		8
> +
> +#define TOPEI_ID_SHIFT		16
> +#define TOPEI_ID_MASK		0x7ff
> +#define TOPEI_PRIO_MASK		0x7ff
> +
> +#define ISELECT_IPRIO0		0x30
> +#define ISELECT_IPRIO15		0x3f
> +#define ISELECT_MASK		0x1ff
> +
> +#define HVICTL_VTI		0x40000000
> +#define HVICTL_IID		0x0fff0000
> +#define HVICTL_IID_SHIFT	16
> +#define HVICTL_IPRIOM		0x00000100
> +#define HVICTL_IPRIO		0x000000ff

Why not name these as masks, like you did for the other masks?
Also, the mask/shift defines appear inconsistent. TOPI_IID_MASK is
intended to be used post-shift AFAICT, but HVICTL_IID_SHIFT is intended
to be used *pre*-shift.
Some consistency in naming and function would be great.

> +/* Machine-Level High-Half CSRs (AIA) */
> +#define CSR_MIDELEGH		0x313

I feel like I could find Midelegh in an Irish dictionary lol
Anyways, I went through the CSRs and they do all seem correct.

Thanks,
Conor.

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