From: Mason <slash.tmp@free.fr>
To: Marc Zyngier <marc.zyngier@arm.com>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Liviu Dudau <liviu.dudau@arm.com>,
David Laight <david.laight@aculab.com>,
linux-pci <linux-pci@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
Phuong Nguyen <phuong_nguyen@sigmadesigns.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v0.2] PCI: Add support for tango PCIe host bridge
Date: Tue, 11 Apr 2017 17:13:35 +0200 [thread overview]
Message-ID: <30f662a6-5dab-515b-e35a-a312f3c7b509@free.fr> (raw)
In-Reply-To: <4edd799a-650c-0189-cd5c-e9fc18c5f8bc@arm.com>
On 27/03/2017 19:09, Marc Zyngier wrote:
> Here's what your system looks like:
>
> PCI-EP -------> MSI Controller ------> INTC
> MSI IRQ
>
> A PCI MSI is always edge. No ifs, no buts. That's what it is, and nothing
> else. Now, your MSI controller signals its output using a level interrupt,
> since you need to whack it on the head so that it lowers its line.
>
> There is not a single trigger, because there is not a single interrupt.
Hello Marc,
I was hoping you or Thomas might help clear some confusion
in my mind around IRQ domains (struct irq_domain).
I have read https://www.kernel.org/doc/Documentation/IRQ-domain.txt
IIUC, there should be one IRQ domain per IRQ controller.
I have this MSI controller handling 256 interrupts, so I should
have *one* domain for all possible MSIs. Yet the Altera driver
registers *two* domains (msi_domain and inner_domain).
Could I make everything work with a single IRQ domain?
I'm confused by the sequence:
irq_dom = irq_domain_create_linear(fwnode, MSI_COUNT, &msi_dom_ops, pcie);
msi_dom = pci_msi_create_irq_domain(fwnode, &msi_domain_info, irq_dom);
It seems I should be able to call only pci_msi_create_irq_domain...
And the parent of the MSI controller is given in the DT.
I'm not quite sure how I tell pci_msi_create_irq_domain how many
MSIs it's supposed to manage. Nor how I pass my private struct.
I will keep looking.
Regards.
next prev parent reply other threads:[~2017-04-11 15:14 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-23 13:05 [RFC PATCH v0.2] PCI: Add support for tango PCIe host bridge Mason
2017-03-23 14:22 ` Marc Zyngier
2017-03-23 17:03 ` Mason
2017-03-23 23:40 ` Mason
2017-03-24 18:22 ` Marc Zyngier
2017-03-27 14:35 ` Mason
2017-03-27 14:46 ` Thomas Gleixner
2017-03-27 15:18 ` Mason
2017-03-24 18:47 ` Marc Zyngier
2017-03-27 15:53 ` Mason
2017-03-27 17:09 ` Marc Zyngier
2017-03-27 19:44 ` Mason
2017-03-27 21:07 ` Marc Zyngier
2017-03-27 22:04 ` Mason
2017-03-28 8:21 ` Marc Zyngier
2017-04-11 15:13 ` Mason [this message]
2017-04-11 15:49 ` Marc Zyngier
2017-04-11 16:26 ` Mason
2017-04-11 16:43 ` Marc Zyngier
2017-04-11 17:52 ` Mason
2017-04-12 8:08 ` Marc Zyngier
2017-04-12 9:50 ` Mason
2017-04-12 9:59 ` Marc Zyngier
2017-04-19 11:19 ` Mason
2017-04-20 8:20 ` Mason
2017-04-20 9:43 ` Marc Zyngier
2017-03-29 11:39 ` Mason
2017-03-30 11:09 ` Mason
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