From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFCv1 07/11] irqchip: armada-370-xp: add MSI support to interrupt controller driver
Date: Tue, 26 Mar 2013 21:53:53 +0000 [thread overview]
Message-ID: <201303262153.53698.arnd@arndb.de> (raw)
In-Reply-To: <20130326223748.242f0046@skate>
On Tuesday 26 March 2013, Thomas Petazzoni wrote:
> On Tue, 26 Mar 2013 21:10:15 +0000, Arnd Bergmann wrote:
>
> > > To which children? Only to the main-intc children? If so,
> > > armada_370_xp_mpic_of_init() would be called with a 'device_node *'
> > > that points to the main-intc, correct? Then it would have to go back up
> > > in the Device Tree to find the msi node? It's doable of course, but
> > > sounds strange, no?
> >
> > I was thinking of registering two init functions as well.
>
> But then which of the two init functions would do the of_iomap() (or
> whatever ioremap()ing function you use) ?
I agree this is where it get a little fishy, hence my preference to
use a single node.
> Remember, the very reason what we have one driver for both interrupt
> controllers is because the registers are completely mixed. So to me
> it's really the case of one device providing two features, like a
> device that would be both an Ethernet interface and a SPI controller.
> You have a single ->probe() function that gets called when the device
> is detected, and this ->probe() function registers both an Ethernet
> interface and a SPI controller.b
>
> To me, the case we have here is really identical: we have one single set
> of registers that provide multiple features.
The problem here is that the irq subsystem makes certain assumptions
about one device node being the controller and mapping to a single
irq domain, so you'd have to cheat one way or another. Using the
sub-nodes the way you do in your patch is bending the rules for
the device tree binding, which I think is more problematic than
bending the rules for the code. Regarding the call to of_iomap(),
you could work around it by having a static variable in the driver
that remembers the mmio address and gets set by whichever device node
init function gets called first.
Arnd
next prev parent reply other threads:[~2013-03-26 21:53 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-26 16:52 [RFCv1 00/11] MSI support for Marvell EBU PCIe driver Thomas Petazzoni
[not found] ` <1364316746-8702-2-git-send-email-thomas.petazzoni@free-electrons.com>
2013-03-26 16:53 ` [RFCv1 01/11] arm: mvebu: move L2 cache initialization in init_early() Arnd Bergmann
2013-03-26 17:02 ` Thomas Petazzoni
2013-03-27 1:53 ` Rob Herring
[not found] ` <1364316746-8702-3-git-send-email-thomas.petazzoni@free-electrons.com>
2013-03-26 16:54 ` [RFCv1 02/11] irqchip: move IRQ driver for Armada 370/XP Arnd Bergmann
2013-03-26 17:05 ` [RFCv1 00/11] MSI support for Marvell EBU PCIe driver Thomas Petazzoni
2013-03-26 17:18 ` Arnd Bergmann
2013-03-26 17:21 ` Thomas Petazzoni
[not found] ` <1364316746-8702-8-git-send-email-thomas.petazzoni@free-electrons.com>
2013-03-26 17:07 ` [RFCv1 07/11] irqchip: armada-370-xp: add MSI support to interrupt controller driver Arnd Bergmann
2013-03-26 17:17 ` Thomas Petazzoni
2013-03-26 18:38 ` Arnd Bergmann
2013-03-26 20:46 ` Thomas Petazzoni
2013-03-26 21:10 ` Arnd Bergmann
2013-03-26 21:37 ` Thomas Petazzoni
2013-03-26 21:53 ` Arnd Bergmann [this message]
2013-03-26 21:14 ` Jason Gunthorpe
2013-03-26 21:41 ` Thomas Petazzoni
2013-03-26 18:02 ` Jason Gunthorpe
2013-03-26 21:16 ` Thomas Petazzoni
2013-03-26 21:31 ` Arnd Bergmann
2013-03-26 21:47 ` Thomas Petazzoni
2013-03-26 21:55 ` Jason Gunthorpe
2013-03-26 22:04 ` Arnd Bergmann
2013-03-26 22:06 ` Thomas Petazzoni
2013-03-26 22:26 ` Jason Gunthorpe
2013-03-26 21:15 ` Arnd Bergmann
2013-03-26 21:42 ` Thomas Petazzoni
2013-04-04 9:16 ` [RFCv1 00/11] MSI support for Marvell EBU PCIe driver Ezequiel Garcia
2013-04-04 9:29 ` Thomas Petazzoni
[not found] ` <1364316746-8702-9-git-send-email-thomas.petazzoni@free-electrons.com>
2013-04-08 22:28 ` [RFCv1 08/11] PCI: Introduce new MSI chip infrastructure Bjorn Helgaas
2013-04-09 8:11 ` Andrew Murray
2013-04-09 8:22 ` Thierry Reding
2013-04-09 8:25 ` Andrew Murray
2013-04-09 8:18 ` Thierry Reding
[not found] ` <1364316746-8702-10-git-send-email-thomas.petazzoni@free-electrons.com>
2013-03-27 10:07 ` [RFCv1 09/11] pci: mvebu: add MSI support Andrew Murray
2013-04-08 22:29 ` Bjorn Helgaas
2013-05-30 12:15 ` Thierry Reding
2013-05-30 18:13 ` Bjorn Helgaas
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