linux-kernel - Re: [PATCH 0/6] Add support for the ICU unit in Marvell Armada 7K/8K

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Message-ID: <cc93efea-84ea-970d-914a-141241b8cace@arm.com>
Date:   Tue, 30 May 2017 15:15:54 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>,
        Kumar Gala <galak@...eaurora.org>,
        Andrew Lunn <andrew@...n.ch>,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
        Gregory Clement <gregory.clement@...e-electrons.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Nadav Haklai <nadavh@...vell.com>,
        Hanna Hawa <hannah@...vell.com>,
        Yehuda Yitschak <yehuday@...vell.com>,
        Antoine Tenart <antoine.tenart@...e-electrons.com>
Subject: Re: [PATCH 0/6] Add support for the ICU unit in Marvell Armada 7K/8K

Hi Thomas,

On 30/05/17 10:16, Thomas Petazzoni wrote:
> Hello,
> 
> The Marvell Armada 7K/8K SoCs are composed of two parts: the AP (which
> contains the CPU cores) and the CP (which contains most
> peripherals). The 7K SoCs have one CP, while the 8K SoCs have two CPs,
> doubling the number of available peripherals.
> 
> In terms of interrupt handling, all devices in the CPs are connected
> through wired interrupt to a unit called ICU located in each CP. This
> unit converts the wired interrupts from the devices into memory
> transactions.
> 
> Inside the AP, there is a GIC extension called GICP, which allows a
> memory write transaction to trigger a GIC SPI interrupt. The ICUs in
> each CP are therefore configured to trigger a memory write into the
> appropriate GICP register so that a wired interrupt from a CP device
> is converted into a memory write, itself converted into a regular GIC
> SPI interrupt.
> 
> Until now, the configuration of the ICU was done statically by the
> firmware, and therefore the Device Tree files in Linux were specifying
> directly GIC interrupts for the interrupts of CP devices. However,
> with the growing number of devices in the CP, a static allocation
> scheme doesn't work for the long term.
> 
> This patch series therefore makes Linux aware of the ICU: GIC SPI
> interrupts are dynamically allocated, and the ICU is configured
> accordingly to route a CP wired interrupt to the allocated GIC SPI
> interrupt.
> 
> In detail:
> 
>  - The first two patches are the Device Tree binding patches
> 
>  - The third patch is a minimal driver for the GICP unit. All it does
>    is clear interrupts that may have been left pending by the
>    firmware.
> 
>  - The fourth patch is the most important done, which adds the driver
>    for the ICU itself.
> 
>  - The fifth patch adjust Kconfig.platforms to select the GICP and ICU
>    drivers.
> 
>  - The last patch adjusts the Device Tree files of the Armada 7K/8K to
>    use the ICU.

For a first drop, this looks quite good, and the few comments I've had
should be pretty easy to address. Looking forward to reviewing v2.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...