On Thu, Dec 24, 2020 at 8:35 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > > On Wed, 2020-12-23 at 17:18 +0900, Tomasz Figa wrote: > > On Wed, Dec 09, 2020 at 04:00:41PM +0800, Yong Wu wrote: > > > This patch adds decriptions for mt8192 IOMMU and SMI. > > > > > > mt8192 also is MTK IOMMU gen2 which uses ARM Short-Descriptor translation > > > table format. The M4U-SMI HW diagram is as below: > > > > > > EMI > > > | > > > M4U > > > | > > > ------------ > > > SMI Common > > > ------------ > > > | > > > +-------+------+------+----------------------+-------+ > > > | | | | ...... | | > > > | | | | | | > > > larb0 larb1 larb2 larb4 ...... larb19 larb20 > > > disp0 disp1 mdp vdec IPE IPE > > > > > > All the connections are HW fixed, SW can NOT adjust it. > > > > > > mt8192 M4U support 0~16GB iova range. we preassign different engines > > > into different iova ranges: > > > > > > domain-id module iova-range larbs > > > 0 disp 0 ~ 4G larb0/1 > > > 1 vcodec 4G ~ 8G larb4/5/7 > > > 2 cam/mdp 8G ~ 12G larb2/9/11/13/14/16/17/18/19/20 > > > > Why do we preassign these addresses in DT? Shouldn't it be a user's or > > integrator's decision to split the 16 GB address range into sub-ranges > > and define which larbs those sub-ranges are shared with? > > The problem is that we can't split the 16GB range with the larb as unit. > The example is the below ccu0(larb13 port9/10) is a independent > range(domain), the others ports in larb13 is in another domain. > > disp/vcodec/cam/mdp don't have special iova requirement, they could > access any range. vcodec also can locate 8G~12G. it don't care about > where its iova locate. here I preassign like this following with our > internal project setting. Let me try to understand this a bit more. Given the split you're proposing, is there actually any isolation enforced between particular domains? For example, if I program vcodec to with a DMA address from the 0-4G range, would the IOMMU actually generate a fault, even if disp had some memory mapped at that address? > > Why set this in DT?, this is only for simplifying the code. Assume we > put it in the platform data. We have up to 32 larbs, each larb has up to > 32 ports, each port may be in different iommu domains. we should have a > big array for this..however we only use a macro to get the domain in the > DT method. > > When replying this mail, I happen to see there is a "dev->dev_range_map" > which has "dma-range" information, I think I could use this value to get > which domain the device belong to. then no need put domid in DT. I will > test this. My feeling is that the only part that needs to be enforced statically is the reserved IOVA range for CCUs. The other ranges should be determined dynamically, although I think I need to understand better how the hardware and your proposed design work to tell what would be likely the best choice here. Best regards, Tomasz > > Thanks. > > > > Best regards, > > Tomasz > > > > > 3 CCU0 0x4000_0000 ~ 0x43ff_ffff larb13: port 9/10 > > > 4 CCU1 0x4400_0000 ~ 0x47ff_ffff larb14: port 4/5 > > > > > > The iova range for CCU0/1(camera control unit) is HW requirement. > > > > > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > > > --- > > > .../bindings/iommu/mediatek,iommu.yaml | 18 +- > > > include/dt-bindings/memory/mt8192-larb-port.h | 240 ++++++++++++++++++ > > > 2 files changed, 257 insertions(+), 1 deletion(-) > > > create mode 100644 include/dt-bindings/memory/mt8192-larb-port.h > > > > [snip]
