On Wed, 2021-01-20 at 13:15 +0900, Tomasz Figa wrote: > On Wed, Jan 13, 2021 at 3:45 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > > > > On Wed, 2021-01-13 at 14:30 +0900, Tomasz Figa wrote: > > > 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? > > > > In this case. we will get fault in current SW setting. > > > > Okay, thanks. > > > > > > > > > > > > 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. > > > > I have removed the domid patch in v6. and get the domain id in [27/33] > > in v6.. > > > > About the other ranges should be dynamical, the commit message [30/33] > > of v6 should be helpful. the problem is that we have a bank_sel setting > > for the iova[32:33]. currently we preassign this value. thus, all the > > ranges are fixed. If you adjust this setting, you can let vcodec access > > 0~4G. > > Okay, so it sounds like we effectively have four 4G address spaces and > we can assign the master devices to them. I guess each of these > address spaces makes for an IOMMU group. Yes. Each a address spaces is an IOMMU group. > > It's fine to pre-assign the devices to those groups for now, but it > definitely shouldn't be hardcoded in DT, because it depends on the use > case of the device. I'll take a look at v6, but it sounds like it > should be fine if it doesn't take the address space assignment from DT > anymore. Thanks very much for your review. > > > > > Currently we have no interface to adjust this setting. Suppose we add a > > new interface for this. It would be something like: > > > > int mtk_smi_larb_config_banksel(struct device *larb, int banksel) > > > > Then, all the MM drivers should call it before the HW works every > > time, and its implement will be a bit complex since we aren't sure if > > the larb has power at that time. the important thing is that the MM > > devices have already not known which larb it connects with as we plan to > > delete "mediatek,larb" in their dtsi nodes. > > From the practical point of view, it doesn't look like setting this on > a per-larb basis would make much sense. The reason to switch the > bank_sel would be to decide which MM devices can share the same > address space. This is a security aspect, because it effectively > determines which devices are isolated from each other. > > That said, I agree that for now we can just start with a fixed > assignment. We can think of the API if there is a need to adjust the > assignment. Sorry for here. I forgot a thing here. that interface above still will not be helpful. If we don't divide the whole 16GB ranges into 4 regions(let all the other ranges be dynamical), It won't work since we can only adjust bank_sel with the larb as unit. This is a problem. there are many ports in a larb. Take a example, the address for vcodec read port is 32bits while the address for vcodec write port is 33bit, then it will fail since we only have one bank_sel setting for one larb. Thus we have to use current design. > > > > > In current design, the MM device don't need care about it and 4GB > > range is enough for them. > > > > Actually, is the current assignment correct? Oh. In the code (patch [32/33] of v6), I put CCU0/1 in the cam/mdp region which start at 8G since CCU0/1 is a module of camera. > > 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 > 3 CCU0 0x4000_0000 ~ 0x43ff_ffff larb13: port 9/10 > 4 CCU1 0x4400_0000 ~ 0x47ff_ffff larb14: port 4/5 > > Wouldn't CCU0 and CCU1 conflict with disp? About the conflict, I use patch [29/33] of v6 for this. I will reserve this special iova region when the full domain(0-4G in this example) initialize. > Should perhaps disp be assigned 12G ~ 16G instead? I think no need put it to 12G-16G, In previous SoC, we have only 4GB ranges for whole MM engines. currently only cam/mdp domain exclude 128M for CCU. it should be something wrong if this is not enough. > > Best regards, > Tomasz > > > > > > > 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] > >
