[PATCH v5 08/13] iommu/rockchip: Control clocks needed to access the IOMMU
robh at kernel.org
Tue Jan 30 09:05:15 PST 2018
On Wed, Jan 24, 2018 at 06:35:11PM +0800, Jeffy Chen wrote:
> From: Tomasz Figa <tfiga at chromium.org>
> Current code relies on master driver enabling necessary clocks before
> IOMMU is accessed, however there are cases when the IOMMU should be
> accessed while the master is not running yet, for example allocating
> V4L2 videobuf2 buffers, which is done by the VB2 framework using DMA
> mapping API and doesn't engage the master driver at all.
> This patch fixes the problem by letting clocks needed for IOMMU
> operation to be listed in Device Tree and making the driver enable them
> for the time of accessing the hardware.
> Signed-off-by: Jeffy Chen <jeffy.chen at rock-chips.com>
> Signed-off-by: Tomasz Figa <tfiga at chromium.org>
> Changes in v5:
> Use clk_bulk APIs.
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> .../devicetree/bindings/iommu/rockchip,iommu.txt | 8 +++
Please split binding patches to a separate patch.
> drivers/iommu/rockchip-iommu.c | 74 ++++++++++++++++++++--
> 2 files changed, 76 insertions(+), 6 deletions(-)
> diff --git a/Documentation/devicetree/bindings/iommu/rockchip,iommu.txt b/Documentation/devicetree/bindings/iommu/rockchip,iommu.txt
> index 2098f7732264..33dd853359fa 100644
> --- a/Documentation/devicetree/bindings/iommu/rockchip,iommu.txt
> +++ b/Documentation/devicetree/bindings/iommu/rockchip,iommu.txt
> @@ -14,6 +14,13 @@ Required properties:
> "single-master" device, and needs no additional information
> to associate with its master device. See:
> +Optional properties:
> +- clocks : A list of master clocks requires for the IOMMU to be accessible
> + by the host CPU. The number of clocks depends on the master
> + block and might as well be zero. See  for generic clock
> + bindings description.
Hardware blocks don't have a variable number of clock connections. This
needs to be a defined number of clocks (per compatible string if there
are different implementations with different # of clocks).
> + Documentation/devicetree/bindings/clock/clock-bindings.txt
> Optional properties:
> - rockchip,disable-mmu-reset : Don't use the mmu reset operation.
> @@ -27,5 +34,6 @@ Example:
> reg = <0xff940300 0x100>;
> interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
> interrupt-names = "vopl_mmu";
> + clocks = <&cru ACLK_VOP1>, <&cru DCLK_VOP1>, <&cru HCLK_VOP1>;
> #iommu-cells = <0>;
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