From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www.hansjkoch.de (www.hansjkoch.de [178.63.77.200]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 753321007DB for ; Sat, 29 Oct 2011 08:48:31 +1100 (EST) Date: Fri, 28 Oct 2011 23:48:12 +0200 From: "Hans J. Koch" To: Kumar Gala Subject: Re: [RFC][PATCH 1/2] uio: allow drivers to override the pgprot for mmap Message-ID: <20111028214812.GD23092@local> References: <1319817030-23992-1-git-send-email-galak@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1319817030-23992-1-git-send-email-galak@kernel.crashing.org> Cc: Greg KH , hjk@hansjkoch.de, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Oct 28, 2011 at 10:50:29AM -0500, Kumar Gala wrote: > For some devices, the default behavior of pgprot_noncached() is not > appropriate for all of its mappable regions. This provides a means for > the kernel side of the UIO driver to override the flags without having > to implement its own full mmap callback. Thanks for also providing an example driver showing the use of this. You should also post this driver in a mainline-ready version, I'm a bit uncomfortable with adding a new function pointer without having any users. And since you change uio_driver.h you should also update documentation accordingly (Documentation/DocBook/uio-howto.tmpl). Otherwise, I have no general objections. Thanks, Hans > > Signed-off-by: Kumar Gala > Signed-off-by: Geoff Thorpe > --- > drivers/uio/uio.c | 6 +++++- > include/linux/uio_driver.h | 3 +++ > 2 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c > index dc27d89..0aebe27 100644 > --- a/drivers/uio/uio.c > +++ b/drivers/uio/uio.c > @@ -655,7 +655,11 @@ static int uio_mmap_physical(struct vm_area_struct *vma) > > vma->vm_flags |= VM_IO | VM_RESERVED; > > - vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > + if (idev->info->set_pgprot) > + vma->vm_page_prot = idev->info->set_pgprot(idev->info, mi, > + vma->vm_page_prot); > + else > + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > > return remap_pfn_range(vma, > vma->vm_start, > diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h > index fd99ff9..edfe7c8 100644 > --- a/include/linux/uio_driver.h > +++ b/include/linux/uio_driver.h > @@ -80,6 +80,7 @@ struct uio_device; > * @open: open operation for this uio device > * @release: release operation for this uio device > * @irqcontrol: disable/enable irqs when 0/1 is written to /dev/uioX > + * @set_pgprot: allow driver to override default(noncached) pgprot > */ > struct uio_info { > struct uio_device *uio_dev; > @@ -95,6 +96,8 @@ struct uio_info { > int (*open)(struct uio_info *info, struct inode *inode); > int (*release)(struct uio_info *info, struct inode *inode); > int (*irqcontrol)(struct uio_info *info, s32 irq_on); > + pgprot_t (*set_pgprot)(struct uio_info *uio, unsigned int mem_idx, > + pgprot_t prot); > }; > > extern int __must_check > -- > 1.7.3.4 > >