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From: Jiri Slaby <jirislaby@kernel.org>
To: Bin Meng <bmeng@tinylab.org>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Russell King <linux@armlinux.org.uk>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h
Date: Thu, 8 Dec 2022 07:08:33 +0100	[thread overview]
Message-ID: <0443d5e9-b2ce-7e6b-c69b-708d67a5bf97@kernel.org> (raw)
In-Reply-To: <20221207135352.592556-1-bmeng@tinylab.org>

On 07. 12. 22, 14:53, Bin Meng wrote:
> Move smh_putc() variants in respective arch/*/include/asm/semihost.h,
> in preparation to add RISC-V support.
> 
> Signed-off-by: Bin Meng <bmeng@tinylab.org>
...
> --- /dev/null
> +++ b/arch/arm/include/asm/semihost.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2012 ARM Ltd.
> + * Author: Marc Zyngier <marc.zyngier@arm.com>
> + *
> + * Adapted for ARM and earlycon:
> + * Copyright (C) 2014 Linaro Ltd.
> + * Author: Rob Herring <robh@kernel.org>
> + */

Much better. There are three minor issues:
1) protection against multiple #include-s is missing here.

> +#ifdef CONFIG_THUMB2_KERNEL
> +#define SEMIHOST_SWI	"0xab"
> +#else
> +#define SEMIHOST_SWI	"0x123456"
> +#endif
> +
> +static inline void smh_putc(struct uart_port *port, unsigned char c)

2) port is unused in all implementations. So it should be dropped.
3) can you make "c" an explicit u8?

> +{
> +	asm volatile("mov  r1, %0\n"
> +		     "mov  r0, #3\n"
> +		     "svc  " SEMIHOST_SWI "\n"
> +		     : : "r" (&c) : "r0", "r1", "memory");
> +}

thanks,
-- 
js
suse labs


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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Jiri Slaby <jirislaby@kernel.org>
To: Bin Meng <bmeng@tinylab.org>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Russell King <linux@armlinux.org.uk>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h
Date: Thu, 8 Dec 2022 07:08:33 +0100	[thread overview]
Message-ID: <0443d5e9-b2ce-7e6b-c69b-708d67a5bf97@kernel.org> (raw)
In-Reply-To: <20221207135352.592556-1-bmeng@tinylab.org>

On 07. 12. 22, 14:53, Bin Meng wrote:
> Move smh_putc() variants in respective arch/*/include/asm/semihost.h,
> in preparation to add RISC-V support.
> 
> Signed-off-by: Bin Meng <bmeng@tinylab.org>
...
> --- /dev/null
> +++ b/arch/arm/include/asm/semihost.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2012 ARM Ltd.
> + * Author: Marc Zyngier <marc.zyngier@arm.com>
> + *
> + * Adapted for ARM and earlycon:
> + * Copyright (C) 2014 Linaro Ltd.
> + * Author: Rob Herring <robh@kernel.org>
> + */

Much better. There are three minor issues:
1) protection against multiple #include-s is missing here.

> +#ifdef CONFIG_THUMB2_KERNEL
> +#define SEMIHOST_SWI	"0xab"
> +#else
> +#define SEMIHOST_SWI	"0x123456"
> +#endif
> +
> +static inline void smh_putc(struct uart_port *port, unsigned char c)

2) port is unused in all implementations. So it should be dropped.
3) can you make "c" an explicit u8?

> +{
> +	asm volatile("mov  r1, %0\n"
> +		     "mov  r0, #3\n"
> +		     "svc  " SEMIHOST_SWI "\n"
> +		     : : "r" (&c) : "r0", "r1", "memory");
> +}

thanks,
-- 
js
suse labs


WARNING: multiple messages have this Message-ID (diff)
From: Jiri Slaby <jirislaby@kernel.org>
To: Bin Meng <bmeng@tinylab.org>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-serial@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Russell King <linux@armlinux.org.uk>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h
Date: Thu, 8 Dec 2022 07:08:33 +0100	[thread overview]
Message-ID: <0443d5e9-b2ce-7e6b-c69b-708d67a5bf97@kernel.org> (raw)
In-Reply-To: <20221207135352.592556-1-bmeng@tinylab.org>

On 07. 12. 22, 14:53, Bin Meng wrote:
> Move smh_putc() variants in respective arch/*/include/asm/semihost.h,
> in preparation to add RISC-V support.
> 
> Signed-off-by: Bin Meng <bmeng@tinylab.org>
...
> --- /dev/null
> +++ b/arch/arm/include/asm/semihost.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2012 ARM Ltd.
> + * Author: Marc Zyngier <marc.zyngier@arm.com>
> + *
> + * Adapted for ARM and earlycon:
> + * Copyright (C) 2014 Linaro Ltd.
> + * Author: Rob Herring <robh@kernel.org>
> + */

Much better. There are three minor issues:
1) protection against multiple #include-s is missing here.

> +#ifdef CONFIG_THUMB2_KERNEL
> +#define SEMIHOST_SWI	"0xab"
> +#else
> +#define SEMIHOST_SWI	"0x123456"
> +#endif
> +
> +static inline void smh_putc(struct uart_port *port, unsigned char c)

2) port is unused in all implementations. So it should be dropped.
3) can you make "c" an explicit u8?

> +{
> +	asm volatile("mov  r1, %0\n"
> +		     "mov  r0, #3\n"
> +		     "svc  " SEMIHOST_SWI "\n"
> +		     : : "r" (&c) : "r0", "r1", "memory");
> +}

thanks,
-- 
js
suse labs


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-12-08  6:08 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-07 13:53 [PATCH v2 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h Bin Meng
2022-12-07 13:53 ` Bin Meng
2022-12-07 13:53 ` Bin Meng
2022-12-07 13:53 ` [PATCH v2 2/3] riscv: Implement semihost.h for earlycon semihost driver Bin Meng
2022-12-07 13:53   ` Bin Meng
2022-12-07 16:40   ` Conor Dooley
2022-12-07 16:40     ` Conor Dooley
2022-12-07 13:53 ` [PATCH v2 3/3] serial: Rename " Bin Meng
2022-12-07 13:53   ` Bin Meng
2022-12-08  6:08 ` Jiri Slaby [this message]
2022-12-08  6:08   ` [PATCH v2 1/3] serial: earlycon-arm-semihost: Move smh_putc() variants in respective arch's semihost.h Jiri Slaby
2022-12-08  6:08   ` Jiri Slaby
2022-12-08  9:32   ` Bin Meng
2022-12-08  9:32     ` Bin Meng
2022-12-08  9:32     ` Bin Meng
2022-12-08  9:37     ` Jiri Slaby
2022-12-08  9:37       ` Jiri Slaby
2022-12-08  9:37       ` Jiri Slaby

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