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From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Stephen Warren <swarren@wwwdotorg.org>,
	linux-tegra@vger.kernel.org,
	Grant Likely <grant.likely@secretlab.ca>,
	Rob Herring <rob.herring@calxeda.com>,
	Russell King <linux@arm.linux.org.uk>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Andrew Murray <andrew.murray@arm.com>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	devicetree-discuss@lists.ozlabs.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 05/14] lib: Add I/O map cache implementation
Date: Thu, 10 Jan 2013 12:24:17 -0700	[thread overview]
Message-ID: <20130110192417.GA18478@obsidianresearch.com> (raw)
In-Reply-To: <20130110190327.GA23110@avionic-0098.adnet.avionic-design.de>

On Thu, Jan 10, 2013 at 08:03:27PM +0100, Thierry Reding wrote:

> > > You'd piece a mapping together, each bus requires 16 64k mappings, a
> > > simple 2d array of busnr*16 of pointers would do the trick. A more
> > > clever solution would be to allocate contiguous virtual memory and
> > > split that up..
 
> > Oh, I see. I'm not very familiar with the internals of remapping, so
> > I'll need to do some more reading. Thanks for the hints.
> 
> I forgot to ask. What's the advantage of having a contiguous virtual
> memory area and splitting it up versus remapping each chunk separately?

Not alot, really, but it saves you from the pointer array and
associated overhead. IIRC it is fairly easy to do in the kernel.

Arnd's version is good too, but you would be restricted to aligned
powers of two for the bus number range in the DT, which is probably
not that big a deal either?

Jason

  reply	other threads:[~2013-01-10 19:24 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-09 20:43 [PATCH 00/14] Rewrite Tegra PCIe driver Thierry Reding
2013-01-09 20:43 ` [PATCH 01/14] of/pci: Provide support for parsing PCI DT ranges property Thierry Reding
2013-01-11  0:06   ` Stephen Warren
2013-01-11  4:02     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 02/14] of/pci: Add of_pci_get_devfn() function Thierry Reding
2013-01-11  0:09   ` Stephen Warren
2013-01-11  4:06     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 03/14] of/pci: Add of_pci_get_bus() function Thierry Reding
2013-01-09 20:43 ` [PATCH 04/14] of/pci: Add of_pci_parse_bus_range() function Thierry Reding
2013-01-09 20:43 ` [PATCH 05/14] lib: Add I/O map cache implementation Thierry Reding
2013-01-09 21:19   ` Arnd Bergmann
2013-01-09 21:54     ` Thierry Reding
2013-01-09 22:10       ` Arnd Bergmann
2013-01-09 23:12         ` Stephen Warren
2013-01-09 23:17           ` Jason Gunthorpe
2013-01-10  7:19             ` Thierry Reding
2013-01-10  9:17               ` Arnd Bergmann
2013-01-10 10:25                 ` Thierry Reding
2013-01-10 18:20                   ` Jason Gunthorpe
2013-01-10 18:55                     ` Thierry Reding
2013-01-10 19:03                       ` Thierry Reding
2013-01-10 19:24                         ` Jason Gunthorpe [this message]
2013-01-10 20:20                           ` Thierry Reding
2013-01-10 21:06                             ` Jason Gunthorpe
2013-01-16 10:18                           ` Thierry Reding
2013-01-16 11:25                             ` Russell King - ARM Linux
2013-01-16 11:52                               ` Thierry Reding
2013-01-10 18:26                   ` Arnd Bergmann
2013-01-10 18:57                     ` Thierry Reding
2013-01-10  7:10         ` Thierry Reding
2013-01-09 21:28   ` Russell King - ARM Linux
2013-01-09 21:57     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 06/14] ARM: pci: Keep pci_common_init() around after init Thierry Reding
2013-02-05 20:41   ` Thierry Reding
2013-02-06 16:30     ` Russell King - ARM Linux
2013-02-06 19:35       ` Thierry Reding
2013-02-06  8:36   ` Thomas Petazzoni
2013-02-06 16:38   ` Linus Walleij
2013-02-07  0:54     ` Arnd Bergmann
2013-02-06 17:07       ` Linus Walleij
2013-02-07  1:20         ` Arnd Bergmann
2013-01-09 20:43 ` [PATCH 07/14] ARM: pci: Allow passing per-controller private data Thierry Reding
2013-01-09 20:43 ` [PATCH 08/14] ARM: tegra: Move tegra_pcie_xclk_clamp() to PMC Thierry Reding
2013-01-09 20:43 ` [PATCH 09/14] ARM: tegra: Move pmc.h to include/mach Thierry Reding
2013-01-11  0:15   ` Stephen Warren
2013-01-11  4:08     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 10/14] PCI: tegra: Move PCIe driver to drivers/pci/host Thierry Reding
2013-01-09 21:22   ` Arnd Bergmann
2013-01-09 21:58     ` Thierry Reding
2013-01-09 22:03       ` Arnd Bergmann
2013-01-10 23:54   ` Stephen Warren
2013-01-11  3:40     ` Thierry Reding
2013-01-11 15:36       ` Arnd Bergmann
2013-01-11 15:45         ` Thierry Reding
2013-01-12 12:36           ` Thierry Reding
2013-01-12 21:12             ` Arnd Bergmann
2013-01-13  9:58               ` Thierry Reding
2013-01-14  9:57                 ` Andrew Murray
2013-01-15 12:08                   ` Thierry Reding
2013-01-15 12:44                     ` Arnd Bergmann
2013-01-15 15:40                       ` Andrew Murray
2013-01-15 21:14                         ` Thierry Reding
2013-01-16 14:00                           ` Arnd Bergmann
2013-01-16 16:17                             ` Andrew Murray
2013-01-16 18:31                               ` Thierry Reding
2013-01-17 15:42                                 ` Andrew Murray
2013-01-17 16:05                                   ` Thierry Reding
2013-01-17 16:22                                     ` Andrew Murray
2013-01-17 20:30                                       ` Thierry Reding
2013-01-18  9:18                                         ` Andrew Murray
2013-01-22 19:29                                       ` Jason Gunthorpe
2013-01-29 13:31                                         ` Andrew Murray
2013-01-11  0:48   ` Stephen Warren
2013-01-11  3:52     ` Thierry Reding
2013-01-11 20:34       ` Stephen Warren
2013-01-18  9:56   ` Andrew Murray
2013-01-18 10:09     ` Thierry Reding
2013-02-13 23:11   ` Thomas Petazzoni
2013-01-09 20:43 ` [PATCH 11/14] ARM: tegra: tamonten: Add PCIe support Thierry Reding
2013-01-09 21:23   ` Arnd Bergmann
2013-01-10 20:21     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 12/14] ARM: tegra: tec: " Thierry Reding
2013-01-11  0:22   ` Stephen Warren
2013-01-11  4:34     ` Thierry Reding
2013-01-09 20:43 ` [PATCH 13/14] ARM: tegra: harmony: Initialize PCIe from DT Thierry Reding
2013-01-10 23:58   ` Stephen Warren
2013-01-09 20:43 ` [PATCH 14/14] ARM: tegra: trimslice: " Thierry Reding
2013-01-10 23:56   ` Stephen Warren
2013-01-11 18:48     ` Thierry Reding
2013-01-09 21:25 ` [PATCH 00/14] Rewrite Tegra PCIe driver Thomas Petazzoni
2013-01-10  6:55   ` Thierry Reding
2013-01-10  8:34     ` Thomas Petazzoni
2013-01-28 18:15 ` Bjorn Helgaas

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