From: Bjorn Helgaas <helgaas@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
"Ryder Lee" <ryder.lee@mediatek.com>,
"Jianjun Wang" <jianjun.wang@mediatek.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Matthias Brugger" <matthias.bgg@gmail.com>,
"AngeloGioacchino Del Regno"
<angelogioacchino.delregno@collabora.com>,
"Huacai Chen" <chenhuacai@kernel.org>,
"kernel test robot" <lkp@intel.com>
Subject: Re: [PATCH v2 1/1] PCI: mediatek: Correct type for virt_to_phys()
Date: Mon, 18 Sep 2023 16:14:00 -0500 [thread overview]
Message-ID: <20230918211400.GA208009@bhelgaas> (raw)
In-Reply-To: <ZQWGd/RyKaUBRhUY@smile.fi.intel.com>
On Sat, Sep 16, 2023 at 01:41:59PM +0300, Andy Shevchenko wrote:
> On Thu, Sep 14, 2023 at 03:31:46PM -0500, Bjorn Helgaas wrote:
> > On Thu, Sep 14, 2023 at 10:23:24PM +0300, Andy Shevchenko wrote:
>
> ...
>
> > > - addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
> > > + addr = virt_to_phys((__force void *)port->base + PCIE_MSI_VECTOR);
> >
> > Lots of these drivers use either virt_to_phys() or
> > platform_get_resource_byname() to get a physical address that they
> > then use as the MSI target.
> >
> > But I don't think that's quite right -- the MSI is a DMA transaction
> > on PCI, and in general there's no guarantee that bus addresses are
> > identical to CPU physical addresses, so shouldn't we use a dma_addr_t
> > obtained from the DMA API?
> >
> > dw_pcie_msi_host_init() has a complicated version of this that uses
> > dmam_alloc_coherent().
>
> Fair enough. I leave it to you then to get it fixed properly.
> Consider this as just a heads up for the old report.
Sounds good, thanks!
Bjorn
WARNING: multiple messages have this Message-ID (diff)
From: Bjorn Helgaas <helgaas@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
"Ryder Lee" <ryder.lee@mediatek.com>,
"Jianjun Wang" <jianjun.wang@mediatek.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Matthias Brugger" <matthias.bgg@gmail.com>,
"AngeloGioacchino Del Regno"
<angelogioacchino.delregno@collabora.com>,
"Huacai Chen" <chenhuacai@kernel.org>,
"kernel test robot" <lkp@intel.com>
Subject: Re: [PATCH v2 1/1] PCI: mediatek: Correct type for virt_to_phys()
Date: Mon, 18 Sep 2023 16:14:00 -0500 [thread overview]
Message-ID: <20230918211400.GA208009@bhelgaas> (raw)
In-Reply-To: <ZQWGd/RyKaUBRhUY@smile.fi.intel.com>
On Sat, Sep 16, 2023 at 01:41:59PM +0300, Andy Shevchenko wrote:
> On Thu, Sep 14, 2023 at 03:31:46PM -0500, Bjorn Helgaas wrote:
> > On Thu, Sep 14, 2023 at 10:23:24PM +0300, Andy Shevchenko wrote:
>
> ...
>
> > > - addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
> > > + addr = virt_to_phys((__force void *)port->base + PCIE_MSI_VECTOR);
> >
> > Lots of these drivers use either virt_to_phys() or
> > platform_get_resource_byname() to get a physical address that they
> > then use as the MSI target.
> >
> > But I don't think that's quite right -- the MSI is a DMA transaction
> > on PCI, and in general there's no guarantee that bus addresses are
> > identical to CPU physical addresses, so shouldn't we use a dma_addr_t
> > obtained from the DMA API?
> >
> > dw_pcie_msi_host_init() has a complicated version of this that uses
> > dmam_alloc_coherent().
>
> Fair enough. I leave it to you then to get it fixed properly.
> Consider this as just a heads up for the old report.
Sounds good, thanks!
Bjorn
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-09-18 21:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-14 19:23 [PATCH v2 1/1] PCI: mediatek: Correct type for virt_to_phys() Andy Shevchenko
2023-09-14 19:23 ` Andy Shevchenko
2023-09-14 20:31 ` Bjorn Helgaas
2023-09-14 20:31 ` Bjorn Helgaas
2023-09-16 10:41 ` Andy Shevchenko
2023-09-16 10:41 ` Andy Shevchenko
2023-09-18 21:14 ` Bjorn Helgaas [this message]
2023-09-18 21:14 ` Bjorn Helgaas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230918211400.GA208009@bhelgaas \
--to=helgaas@kernel.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=angelogioacchino.delregno@collabora.com \
--cc=bhelgaas@google.com \
--cc=chenhuacai@kernel.org \
--cc=jianjun.wang@mediatek.com \
--cc=kw@linux.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=linux-pci@vger.kernel.org \
--cc=lkp@intel.com \
--cc=lpieralisi@kernel.org \
--cc=matthias.bgg@gmail.com \
--cc=robh@kernel.org \
--cc=ryder.lee@mediatek.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.