From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Liviu Dudau <Liviu.Dudau@arm.com>,
linux-pci <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
linaro-kernel <linaro-kernel@lists.linaro.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
LAKML <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 1/4] pci: OF: Fix the conversion of IO ranges into IO resources.
Date: Thu, 27 Feb 2014 12:36:27 -0700 [thread overview]
Message-ID: <20140227193627.GA7773@obsidianresearch.com> (raw)
In-Reply-To: <20140227191259.GA31753@bart.dudau.co.uk>
On Thu, Feb 27, 2014 at 07:12:59PM +0000, Liviu Dudau wrote:
> The outstanding issue is how to fix pci_address_to_pio() as it will not
> for for range->cpu_addr > IO_SPACE_LIMIT (16MB in my case).
The default actually looks fine to me, it is the correct behavior for
systems that actually have a dedicated IO space (like x86) where the
'CPU' value for IO is the exact value used in the IO accessor
instructions. In this case the IO_SPACE_LIMIT test is appropriate.
It also looks correct for architectures that use the CPU MMIO address
as the IO address directly (where IO_SPACE_LIMIT would be 4G)
Architectures that use the virtual IO window technique will always
require a custom pci_address_to_pio implementation.
BTW, something that occured to me after reading the patches:
For ARM64 you might want to think about doing away with the fixed
virtual IO window like we see in ARM32. Just use the CPU MMIO address
directly within the kernel, and implement a ioport_map to setup the MM
on demand.
I think the legacy reasons for having all those layers of translation
are probably not applicable to ARM64, and it is much simpler without
the extra translation step....
Arnd, what do you think?
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Liviu Dudau <Liviu.Dudau-5wv7dgnIgG8@public.gmane.org>,
linux-pci <linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Catalin Marinas <Catalin.Marinas-5wv7dgnIgG8@public.gmane.org>,
Will Deacon <Will.Deacon-5wv7dgnIgG8@public.gmane.org>,
linaro-kernel
<linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org>,
"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
LAKML
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH v2 1/4] pci: OF: Fix the conversion of IO ranges into IO resources.
Date: Thu, 27 Feb 2014 12:36:27 -0700 [thread overview]
Message-ID: <20140227193627.GA7773@obsidianresearch.com> (raw)
In-Reply-To: <20140227191259.GA31753-hOhETlTuV5niMG9XS5x8Mg@public.gmane.org>
On Thu, Feb 27, 2014 at 07:12:59PM +0000, Liviu Dudau wrote:
> The outstanding issue is how to fix pci_address_to_pio() as it will not
> for for range->cpu_addr > IO_SPACE_LIMIT (16MB in my case).
The default actually looks fine to me, it is the correct behavior for
systems that actually have a dedicated IO space (like x86) where the
'CPU' value for IO is the exact value used in the IO accessor
instructions. In this case the IO_SPACE_LIMIT test is appropriate.
It also looks correct for architectures that use the CPU MMIO address
as the IO address directly (where IO_SPACE_LIMIT would be 4G)
Architectures that use the virtual IO window technique will always
require a custom pci_address_to_pio implementation.
BTW, something that occured to me after reading the patches:
For ARM64 you might want to think about doing away with the fixed
virtual IO window like we see in ARM32. Just use the CPU MMIO address
directly within the kernel, and implement a ioport_map to setup the MM
on demand.
I think the legacy reasons for having all those layers of translation
are probably not applicable to ARM64, and it is much simpler without
the extra translation step....
Arnd, what do you think?
Jason
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WARNING: multiple messages have this Message-ID (diff)
From: jgunthorpe@obsidianresearch.com (Jason Gunthorpe)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/4] pci: OF: Fix the conversion of IO ranges into IO resources.
Date: Thu, 27 Feb 2014 12:36:27 -0700 [thread overview]
Message-ID: <20140227193627.GA7773@obsidianresearch.com> (raw)
In-Reply-To: <20140227191259.GA31753@bart.dudau.co.uk>
On Thu, Feb 27, 2014 at 07:12:59PM +0000, Liviu Dudau wrote:
> The outstanding issue is how to fix pci_address_to_pio() as it will not
> for for range->cpu_addr > IO_SPACE_LIMIT (16MB in my case).
The default actually looks fine to me, it is the correct behavior for
systems that actually have a dedicated IO space (like x86) where the
'CPU' value for IO is the exact value used in the IO accessor
instructions. In this case the IO_SPACE_LIMIT test is appropriate.
It also looks correct for architectures that use the CPU MMIO address
as the IO address directly (where IO_SPACE_LIMIT would be 4G)
Architectures that use the virtual IO window technique will always
require a custom pci_address_to_pio implementation.
BTW, something that occured to me after reading the patches:
For ARM64 you might want to think about doing away with the fixed
virtual IO window like we see in ARM32. Just use the CPU MMIO address
directly within the kernel, and implement a ioport_map to setup the MM
on demand.
I think the legacy reasons for having all those layers of translation
are probably not applicable to ARM64, and it is much simpler without
the extra translation step....
Arnd, what do you think?
Jason
next prev parent reply other threads:[~2014-02-27 19:36 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 13:06 [PATCH v2 0/4] [RFC] Support for creating generic host_bridge from device tree Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
[not found] ` < 1393506402-11474-5-git-send-email-Liviu.Dudau@arm.com>
2014-02-27 13:06 ` [PATCH v2 1/4] pci: OF: Fix the conversion of IO ranges into IO resources Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:20 ` Arnd Bergmann
2014-02-27 13:20 ` Arnd Bergmann
2014-02-27 13:20 ` Arnd Bergmann
2014-02-27 13:45 ` Liviu Dudau
2014-02-27 13:22 ` Andrew Murray
2014-02-27 13:22 ` Andrew Murray
2014-02-27 13:56 ` Liviu Dudau
2014-02-27 14:08 ` Arnd Bergmann
2014-02-27 14:21 ` Liviu Dudau
2014-02-27 16:00 ` Arnd Bergmann
2014-02-27 14:30 ` Liviu Dudau
2014-02-27 13:58 ` Arnd Bergmann
2014-02-27 13:58 ` Arnd Bergmann
2014-02-27 18:19 ` Jason Gunthorpe
2014-02-27 18:19 ` Jason Gunthorpe
2014-02-27 19:12 ` Liviu Dudau
2014-02-27 19:12 ` Liviu Dudau
2014-02-27 19:12 ` Liviu Dudau
2014-02-27 19:36 ` Jason Gunthorpe [this message]
2014-02-27 19:36 ` Jason Gunthorpe
2014-02-27 19:36 ` Jason Gunthorpe
2014-02-27 19:48 ` Arnd Bergmann
2014-02-27 19:48 ` Arnd Bergmann
2014-02-27 20:07 ` Jason Gunthorpe
2014-02-27 20:07 ` Jason Gunthorpe
2014-02-27 20:22 ` Arnd Bergmann
2014-02-27 20:22 ` Arnd Bergmann
2014-02-27 20:22 ` Arnd Bergmann
2014-02-28 12:50 ` Liviu Dudau
2014-02-28 12:50 ` Liviu Dudau
2014-02-28 12:50 ` Liviu Dudau
2014-02-27 13:06 ` [PATCH v2 2/4] pci: Create pci_host_bridge before its associated bus in pci_create_root_bus Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:22 ` Arnd Bergmann
2014-02-27 13:22 ` Arnd Bergmann
2014-02-27 13:06 ` [PATCH v2 3/4] pci: Introduce a domain number for pci_host_bridge Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:22 ` Arnd Bergmann
2014-02-27 13:22 ` Arnd Bergmann
2014-02-27 13:06 ` [PATCH v2 4/4] pci: Add support for creating a generic host_bridge from device tree Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:06 ` Liviu Dudau
2014-02-27 13:38 ` Arnd Bergmann
2014-02-27 13:38 ` Arnd Bergmann
2014-02-27 13:48 ` Arnd Bergmann
2014-02-27 13:48 ` Arnd Bergmann
2014-02-27 13:48 ` Arnd Bergmann
2014-02-27 14:13 ` Liviu Dudau
2014-02-27 15:58 ` Arnd Bergmann
2014-02-27 16:20 ` Liviu Dudau
2014-02-27 16:45 ` Arnd Bergmann
2014-02-27 16:54 ` Liviu Dudau
2014-02-27 18:42 ` Arnd Bergmann
2014-02-27 23:32 ` Benjamin Herrenschmidt
2014-02-27 23:32 ` Benjamin Herrenschmidt
2014-02-27 23:32 ` Benjamin Herrenschmidt
2014-02-28 8:46 ` Arnd Bergmann
2014-02-28 8:46 ` Arnd Bergmann
2014-02-28 9:55 ` Liviu Dudau
2014-02-28 9:55 ` Liviu Dudau
2014-03-02 1:23 ` Benjamin Herrenschmidt
2014-03-02 1:23 ` Benjamin Herrenschmidt
2014-03-02 1:23 ` Benjamin Herrenschmidt
2014-03-02 1:25 ` Benjamin Herrenschmidt
2014-03-02 1:25 ` Benjamin Herrenschmidt
2014-03-07 18:58 ` Grant Likely
2014-03-07 18:58 ` Grant Likely
2014-03-07 18:58 ` Grant Likely
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