From: tixy@linaro.org (Jon Medhurst (Tixy))
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: dts: juno: Enable some SMMUs
Date: Thu, 18 May 2017 14:13:59 +0100 [thread overview]
Message-ID: <1495113239.3174.11.camel@linaro.org> (raw)
In-Reply-To: <eeb81dbbd7ddfbbccb961c0f20c5cb90f120e89f.1495110010.git.robin.murphy@arm.com>
On Thu, 2017-05-18 at 13:23 +0100, Robin Murphy wrote:
> The IOMMU-backed DMA API support has now been in place for a while and
> proven stable, so there's no real need to keep most of Juno's SMMUs
> disabled. The USB, HDLCDs, and CoreSight ETR all just need to map RAM
> buffers for DMA - enabling their SMMUs obviates CPU bounce buffering for
> USB's streaming DMA to the upper memory bank, and lets the other two
> allocate their relatively large coherent buffers without pressuring CMA.
>
> Some more software work is still needed for the DMA-330 and PCIe before
> those can accommodate SMMU translation correctly in all cases, so we
> leave those alone for now.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
For those that don't already know, status = "disabled" for smmu is
broken in Linux 4.12-rc1, and this fixes it...
https://lkml.org/lkml/2017/5/17/344
> arch/arm64/boot/dts/arm/juno-base.dtsi | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi
> index bfe7d683a42e..02aea43238fc 100644
> --- a/arch/arm64/boot/dts/arm/juno-base.dtsi
> +++ b/arch/arm64/boot/dts/arm/juno-base.dtsi
> @@ -53,7 +53,6 @@
> #global-interrupts = <1>;
> dma-coherent;
> power-domains = <&scpi_devpd 0>;
> - status = "disabled";
> };
>
> gic: interrupt-controller at 2c010000 {
> @@ -546,7 +545,6 @@
> <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>;
> #iommu-cells = <1>;
> #global-interrupts = <1>;
> - status = "disabled";
> };
>
> smmu_hdlcd0: iommu at 7fb20000 {
> @@ -556,7 +554,6 @@
> <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
> #iommu-cells = <1>;
> #global-interrupts = <1>;
> - status = "disabled";
> };
>
> smmu_usb: iommu at 7fb30000 {
> @@ -567,7 +564,6 @@
> #iommu-cells = <1>;
> #global-interrupts = <1>;
> dma-coherent;
> - status = "disabled";
> };
>
> dma at 7ff00000 {
next prev parent reply other threads:[~2017-05-18 13:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-18 12:23 [PATCH] arm64: dts: juno: Enable some SMMUs Robin Murphy
2017-05-18 13:13 ` Jon Medhurst (Tixy) [this message]
2017-05-18 13:20 ` Liviu Dudau
2017-05-18 14:30 ` Robin Murphy
2017-05-18 13:21 ` Liviu Dudau
2017-05-19 17:42 ` Sudeep Holla
2017-06-06 15:45 ` Jean-Philippe Brucker
2017-06-06 15:59 ` Robin Murphy
2017-06-06 16:16 ` Jean-Philippe Brucker
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