From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org,
"Gerlando Falauto" <gerlando.falauto@keymile.com>,
"Lior Amsalem" <alior@marvell.com>,
"Andrew Lunn" <andrew@lunn.ch>,
"Jason Cooper" <jason@lakedaemon.net>,
"Longchamp, Valentin" <Valentin.Longchamp@keymile.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"Jason Gunthorpe" <jgunthorpe@obsidianresearch.com>,
"Gregory Clément" <gregory.clement@free-electrons.com>,
"Ezequiel Garcia" <ezequiel.garcia@free-electrons.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>
Subject: Re: pci-mvebu driver on km_kirkwood
Date: Fri, 21 Feb 2014 16:11:08 +0100 [thread overview]
Message-ID: <20140221161108.50a4c932@skate> (raw)
In-Reply-To: <2193926.ls2teBqnfK@wuerfel>
Dear Arnd Bergmann,
On Fri, 21 Feb 2014 16:05:16 +0100, Arnd Bergmann wrote:
> > *) I don't know if the algorithm to split the BAR into multiple
> > windows is going to be trivial.
>
> The easiest solution would be to special case 'size is between
> 128MB+1 and 192MB' if that turns out to be the most interesting
> case. It's easy enough to make the second window smaller than 64MB
> if we want.
>
> If we want things to be a little fancier, we could use:
>
> switch (size) {
> case (SZ_32M+1) ... (SZ_32M+SZ_16M):
> size2 = size - SZ_32M;
> size -= SZ_32M;
> break;
> case (SZ_64M+1) ... (SZ_64M+SZ_32M):
> size2 = size - SZ_64M;
> size -= SZ_64M;
> break;
> case (SZ_128M+1) ... (SZ_128M+SZ_64M):
> size2 = size - SZ_128M;
> size -= SZ_128M;
> break;
> };
What if the size of your BAR is 128 MB + 64 MB + 32 MB ? Then you need
three windows, and your algorithm doesn't work :-)
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: pci-mvebu driver on km_kirkwood
Date: Fri, 21 Feb 2014 16:11:08 +0100 [thread overview]
Message-ID: <20140221161108.50a4c932@skate> (raw)
In-Reply-To: <2193926.ls2teBqnfK@wuerfel>
Dear Arnd Bergmann,
On Fri, 21 Feb 2014 16:05:16 +0100, Arnd Bergmann wrote:
> > *) I don't know if the algorithm to split the BAR into multiple
> > windows is going to be trivial.
>
> The easiest solution would be to special case 'size is between
> 128MB+1 and 192MB' if that turns out to be the most interesting
> case. It's easy enough to make the second window smaller than 64MB
> if we want.
>
> If we want things to be a little fancier, we could use:
>
> switch (size) {
> case (SZ_32M+1) ... (SZ_32M+SZ_16M):
> size2 = size - SZ_32M;
> size -= SZ_32M;
> break;
> case (SZ_64M+1) ... (SZ_64M+SZ_32M):
> size2 = size - SZ_64M;
> size -= SZ_64M;
> break;
> case (SZ_128M+1) ... (SZ_128M+SZ_64M):
> size2 = size - SZ_128M;
> size -= SZ_128M;
> break;
> };
What if the size of your BAR is 128 MB + 64 MB + 32 MB ? Then you need
three windows, and your algorithm doesn't work :-)
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-02-21 15:11 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-10 16:15 pci-mvebu driver on km_kirkwood Gerlando Falauto
2013-07-10 16:57 ` Thomas Petazzoni
2013-07-10 17:31 ` Gerlando Falauto
2013-07-10 19:56 ` Gerlando Falauto
2013-07-11 7:03 ` Valentin Longchamp
2013-07-12 8:59 ` Thomas Petazzoni
2013-07-15 15:46 ` Valentin Longchamp
2013-07-15 19:51 ` Thomas Petazzoni
2013-07-11 14:32 ` Thomas Petazzoni
2014-02-18 17:29 ` Gerlando Falauto
2014-02-18 20:27 ` Thomas Petazzoni
2014-02-19 8:38 ` Gerlando Falauto
2014-02-19 9:26 ` Thomas Petazzoni
2014-02-19 9:39 ` Gerlando Falauto
2014-02-19 13:37 ` Thomas Petazzoni
2014-02-19 13:37 ` Thomas Petazzoni
2014-02-19 21:45 ` Bjorn Helgaas
2014-02-19 21:45 ` Bjorn Helgaas
2014-02-20 8:55 ` Thomas Petazzoni
2014-02-20 8:55 ` Thomas Petazzoni
2014-02-20 17:35 ` Jason Gunthorpe
2014-02-20 17:35 ` Jason Gunthorpe
2014-02-20 20:29 ` Thomas Petazzoni
2014-02-20 20:29 ` Thomas Petazzoni
2014-02-21 0:32 ` Jason Gunthorpe
2014-02-21 0:32 ` Jason Gunthorpe
2014-02-21 8:34 ` Thomas Petazzoni
2014-02-21 8:34 ` Thomas Petazzoni
2014-02-21 8:58 ` Gerlando Falauto
2014-02-21 8:58 ` Gerlando Falauto
2014-02-21 9:12 ` Thomas Petazzoni
2014-02-21 9:12 ` Thomas Petazzoni
2014-02-21 9:16 ` Gerlando Falauto
2014-02-21 9:16 ` Gerlando Falauto
2014-02-21 9:39 ` Thomas Petazzoni
2014-02-21 9:39 ` Thomas Petazzoni
2014-02-21 12:24 ` Gerlando Falauto
2014-02-21 12:24 ` Gerlando Falauto
2014-02-21 13:47 ` Thomas Petazzoni
2014-02-21 13:47 ` Thomas Petazzoni
2014-02-21 15:05 ` Arnd Bergmann
2014-02-21 15:05 ` Arnd Bergmann
2014-02-21 15:11 ` Thomas Petazzoni [this message]
2014-02-21 15:11 ` Thomas Petazzoni
2014-02-21 15:20 ` Arnd Bergmann
2014-02-21 15:20 ` Arnd Bergmann
2014-02-21 15:37 ` Thomas Petazzoni
2014-02-21 15:37 ` Thomas Petazzoni
2014-02-21 16:39 ` Jason Gunthorpe
2014-02-21 16:39 ` Jason Gunthorpe
2014-02-21 17:05 ` Thomas Petazzoni
2014-02-21 17:05 ` Thomas Petazzoni
2014-02-21 17:31 ` Jason Gunthorpe
2014-02-21 17:31 ` Jason Gunthorpe
2014-02-21 18:05 ` Arnd Bergmann
2014-02-21 18:05 ` Arnd Bergmann
2014-02-21 18:29 ` Gerlando Falauto
2014-02-21 18:29 ` Gerlando Falauto
2014-02-21 18:18 ` Gerlando Falauto
2014-02-21 18:18 ` Gerlando Falauto
2014-02-21 18:45 ` Thomas Petazzoni
2014-02-21 18:45 ` Thomas Petazzoni
2014-02-20 19:18 ` Bjorn Helgaas
2014-02-20 19:18 ` Bjorn Helgaas
2014-02-21 0:24 ` Jason Gunthorpe
2014-02-21 0:24 ` Jason Gunthorpe
2014-02-21 19:05 ` Bjorn Helgaas
2014-02-21 19:05 ` Bjorn Helgaas
2014-02-21 19:21 ` Thomas Petazzoni
2014-02-21 19:21 ` Thomas Petazzoni
2014-02-21 19:53 ` Benjamin Herrenschmidt
2014-02-21 19:53 ` Benjamin Herrenschmidt
2014-02-23 3:43 ` Gavin Shan
2013-07-31 8:03 ` Thomas Petazzoni
2013-07-31 8:26 ` Gerlando Falauto
2013-07-31 9:00 ` Thomas Petazzoni
2013-07-31 20:50 ` Jason Gunthorpe
2013-08-09 14:01 ` Thierry Reding
2013-08-26 9:27 ` Gerlando Falauto
2013-08-26 9:27 ` Gerlando Falauto
2013-08-26 12:02 ` Thierry Reding
2013-08-26 12:02 ` Thierry Reding
2013-08-26 14:49 ` Gerlando Falauto
2013-08-26 14:49 ` Gerlando Falauto
2013-08-26 19:16 ` Jason Gunthorpe
2013-08-26 19:16 ` Jason Gunthorpe
2013-11-04 14:49 ` Gerlando Falauto
2013-11-04 14:49 ` Gerlando Falauto
2013-11-05 8:13 ` Thierry Reding
2013-11-05 8:13 ` Thierry Reding
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