linux-kernel - Re: [PATCH 05/37] char: impi, tpm: depend on HAS

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Message-ID: <251751c2-3d7a-db91-adbe-7d6a7e71f7e5@pengutronix.de>
Date:   Fri, 29 Apr 2022 16:02:22 +0200
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     Niklas Schnelle <schnelle@...ux.ibm.com>,
        Arnd Bergmann <arnd@...db.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-pci@...r.kernel.org, Arnd Bergmann <arnd@...nel.org>,
        Corey Minyard <minyard@....org>,
        Peter Huewe <peterhuewe@....de>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        "moderated list:IPMI SUBSYSTEM" 
        <openipmi-developer@...ts.sourceforge.net>,
        "open list:TPM DEVICE DRIVER" <linux-integrity@...r.kernel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>
Subject: Re: [PATCH 05/37] char: impi, tpm: depend on HAS_IOPORT

Hello Niklas,

On 29.04.22 15:50, Niklas Schnelle wrote:
> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> not being declared. We thus need to add this dependency and ifdef
> sections of code using inb()/outb() as alternative access methods.
> 
> Co-developed-by: Arnd Bergmann <arnd@...nel.org>
> Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>

[snip]

> diff --git a/drivers/char/tpm/tpm_infineon.c b/drivers/char/tpm/tpm_infineon.c
> index 9c924a1440a9..2d2ae37153ba 100644
> --- a/drivers/char/tpm/tpm_infineon.c
> +++ b/drivers/char/tpm/tpm_infineon.c
> @@ -51,34 +51,40 @@ static struct tpm_inf_dev tpm_dev;
>  
>  static inline void tpm_data_out(unsigned char data, unsigned char offset)
>  {
> +#ifdef CONFIG_HAS_IOPORT
>  	if (tpm_dev.iotype == TPM_INF_IO_PORT)
>  		outb(data, tpm_dev.data_regs + offset);
>  	else
> +#endif

This looks ugly. Can't you declare inb/outb anyway and skip the definition,
so you can use IS_ENABLED() here instead?

You can mark the declarations with __compiletime_error("some message"), so
if an IS_ENABLED() reference is not removed at compile time, you get some
readable error message instead of a link error.

Cheers,
Ahmad

>  		writeb(data, tpm_dev.mem_base + tpm_dev.data_regs + offset);
>  }
>  
>  static inline unsigned char tpm_data_in(unsigned char offset)
>  {
> +#ifdef CONFIG_HAS_IOPORT
>  	if (tpm_dev.iotype == TPM_INF_IO_PORT)
>  		return inb(tpm_dev.data_regs + offset);
> -	else
> -		return readb(tpm_dev.mem_base + tpm_dev.data_regs + offset);
> +#endif
> +	return readb(tpm_dev.mem_base + tpm_dev.data_regs + offset);
>  }
>  
>  static inline void tpm_config_out(unsigned char data, unsigned char offset)
>  {
> +#ifdef CONFIG_HAS_IOPORT
>  	if (tpm_dev.iotype == TPM_INF_IO_PORT)
>  		outb(data, tpm_dev.config_port + offset);
>  	else
> +#endif
>  		writeb(data, tpm_dev.mem_base + tpm_dev.index_off + offset);
>  }
>  
>  static inline unsigned char tpm_config_in(unsigned char offset)
>  {
> +#ifdef CONFIG_HAS_IOPORT
>  	if (tpm_dev.iotype == TPM_INF_IO_PORT)
>  		return inb(tpm_dev.config_port + offset);
> -	else
> -		return readb(tpm_dev.mem_base + tpm_dev.index_off + offset);
> +#endif
> +	return readb(tpm_dev.mem_base + tpm_dev.index_off + offset);
>  }
>  
>  /* TPM header definitions */
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index dc56b976d816..1efb58dc1b41 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -879,11 +879,6 @@ static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value)
>  		clkrun_val &= ~LPC_CLKRUN_EN;
>  		iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);
>  
> -		/*
> -		 * Write any random value on port 0x80 which is on LPC, to make
> -		 * sure LPC clock is running before sending any TPM command.
> -		 */
> -		outb(0xCC, 0x80);
>  	} else {
>  		data->clkrun_enabled--;
>  		if (data->clkrun_enabled)
> @@ -894,13 +889,15 @@ static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value)
>  		/* Enable LPC CLKRUN# */
>  		clkrun_val |= LPC_CLKRUN_EN;
>  		iowrite32(clkrun_val, data->ilb_base_addr + LPC_CNTRL_OFFSET);
> -
> -		/*
> -		 * Write any random value on port 0x80 which is on LPC, to make
> -		 * sure LPC clock is running before sending any TPM command.
> -		 */
> -		outb(0xCC, 0x80);
>  	}
> +
> +#ifdef CONFIG_HAS_IOPORT
> +	/*
> +	 * Write any random value on port 0x80 which is on LPC, to make
> +	 * sure LPC clock is running before sending any TPM command.
> +	 */
> +	outb(0xCC, 0x80);
> +#endif
>  }
>  
>  static const struct tpm_class_ops tpm_tis = {


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