Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <cover.1545784679.git.fthain@telegraphics.com.au> <505240b144f1666acf26a3c1e93c8e6868fe1408.1545784679.git.fthain@telegraphics.com.au>
In-Reply-To: <505240b144f1666acf26a3c1e93c8e6868fe1408.1545784679.git.fthain@telegraphics.com.au>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Sat, 29 Dec 2018 23:27:27 +0100
Message-ID: <CAK8P3a0P7r+PCykB1cHq3HBrpHagfJ5WhDV7JR-wu0tGTMSFMA@mail.gmail.com>
Subject: Re: [PATCH v8 13/25] m68k: Dispatch nvram_ops calls to Atari or Mac functions
To:     Finn Thain <fthain@telegraphics.com.au>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Joshua Thompson <funaho@jurai.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-m68k <linux-m68k@lists.linux-m68k.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Dec 26, 2018 at 1:43 AM Finn Thain <fthain@telegraphics.com.au> wrote:

> +
> +static ssize_t m68k_nvram_get_size(void)
> +{
> +       if (MACH_IS_ATARI)
> +               return atari_nvram_get_size();
> +       else if (MACH_IS_MAC)
> +               return mac_pram_get_size();
> +       return -ENODEV;
> +}
> +
> +/* Atari device drivers call .read (to get checksum validation) whereas
> + * Mac and PowerMac device drivers just use .read_byte.
> + */
> +const struct nvram_ops arch_nvram_ops = {
> +#ifdef CONFIG_MAC
> +       .read_byte      = m68k_nvram_read_byte,
> +       .write_byte     = m68k_nvram_write_byte,
> +#endif
> +#ifdef CONFIG_ATARI
> +       .read           = m68k_nvram_read,
> +       .write          = m68k_nvram_write,
> +       .set_checksum   = m68k_nvram_set_checksum,
> +       .initialize     = m68k_nvram_initialize,
> +#endif
> +       .get_size       = m68k_nvram_get_size,
> +};
> +EXPORT_SYMBOL(arch_nvram_ops);

Since the operations are almost entirely distinct, why not have two
separate 'nvram_ops' instances here that each refer to just
the set they actually need?

I was actually expecting one more patch here that would make the
arch_nvram_ops a pointer to one of multiple structures, which would
be easier to do with multiple copies, but I suppose there is no need
for that here (there might be on ppc, I have to look again).

       Arnd