linux-kernel - Re: [PATCH v2 2/3] devres: Add devm_ioremap_shared

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Date:   Wed, 24 Jan 2018 18:15:01 +0100
From:   Ladislav Michl <ladis@...ux-mips.org>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:MEMORY TECHNOLOGY..." <linux-mtd@...ts.infradead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        Borislav Petkov <bp@...e.de>, Ingo Molnar <mingo@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Wei Yongjun <weiyongjun1@...wei.com>
Subject: Re: [PATCH v2 2/3] devres: Add devm_ioremap_shared_resource()

On Wed, Jan 24, 2018 at 06:21:38PM +0200, Andy Shevchenko wrote:
> On Wed, Jan 24, 2018 at 12:07 PM, Ladislav Michl <ladis@...ux-mips.org> wrote:
> > Implement managed ioremap function for shared resources.
> 
> > +#define devm_ioremap_resource(dev, res) \
> > +       __devm_ioremap_resource(dev, res, false)
> > +#define devm_ioremap_shared_resource(dev, res) \
> > +       __devm_ioremap_resource(dev, res, true)
> > +void __iomem *__devm_ioremap_resource(struct device *dev, struct resource *res,
> > +                                     bool shared);
> 
> I would rather do the following:
> 
> _resource() ->  _resource_exclusive()
> 
> #define _resource()  _resource_exclusive()
> 
> Add _resource_shared()
> 
> And use long names below in this file whenever refer to exclusive or
> shared variant.

Two separate functions were also considered, but I was unable to find small
common implementation. If code size does not matter or you can provide a hint
to make this solution small and nice, I'll go for it.

> >  void devm_iounmap(struct device *dev, void __iomem *addr);
> >  int check_signature(const volatile void __iomem *io_addr,
> >                         const unsigned char *signature, int length);
> > +
> >  void devm_ioremap_release(struct device *dev, void *res);
> 
> This part doesn't belong to the change.
> 
> > + * When possible, use devm_ioremap_resource() or
> > + * devm_ioremap_shared_resource() instead.
> > - * Checks that a resource is a valid memory region, requests the memory
> > - * region and ioremaps it. All operations are managed and will be undone
> > - * on driver detach.
> > + * Checks that a resource is a valid memory region, eventually requests the
> > + * memory region and ioremaps it. All operations are managed and will be
> > + * undone on driver detach.
> 
> Wording is changed and no clue in commit message why.

Above will be moved to separate patch.

	ladis