On Dienstag, 17. Januar 2023 13:41:14 CET Michael Tretter wrote: > On Wed, 23 Nov 2022 10:28:41 +0100, Michael Tretter wrote: > > On Tue, 22 Nov 2022 20:47:49 +0100, Nicolas Frattaroli wrote: > > > On Dienstag, 22. November 2022 00:10:25 CET Peter Geis wrote: > > > > On Mon, Nov 21, 2022 at 12:34 PM Ezequiel Garcia > > > > <ezequiel@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > On Mon, Nov 21, 2022 at 2:13 PM Shengyu Qu <wiagn233@xxxxxxxxxxx> wrote: > > > > > > I remember someone said that rga2 has only 32bit address space but not > > > > > > having a mmu or mmu needs to be configured. Better ask by yourself in > > > > > > pine64 discord since I'm not sure about that. > > > > > > 于 2022年11月22日 GMT+08:00 上午12:41:16, Michael Tretter <m.tretter@xxxxxxxxxxxxxx> 写到: > > > > > > >On Tue, 22 Nov 2022 00:01:28 +0800, Shengyu Qu wrote: > > > > > > >> Someone from pine64 discord found that RGA2 doesn't work properly on over > > > > > > >> > > > > > > >> 4GB memory RK3568 devices. Are you sure current driver works now? > > > > > > > > > > > > > >I am absolutely sure that the driver works on a 2GB ROCK3A board. > > > > > > >Unfortunately, I don't have a device with 4GB or more memory and I cannot test > > > > > > >the driver with such a device. > > > > > > > > > > > > > >As the documentation for the RGA2 is the same in the TRM of the rk3288 and > > > > > > >rk3568, I would guess that the driver doesn't work on a rk3288 with more than > > > > > > >4GB (if there is such a thing) either and the driver needs to be fixed for > > > > > > >both SoCs. > > > > > > > > > > > > > > > > > In any case, if there's some kind of issue it must be in the driver, > > > > > and not in the device tree binding (i.e. this patchset). > > > > > > > > An unfortunate number of Rockchip drivers break on rk356x boards with > > > > more than 4GB of ram. I've found requesting memory allocations with > > > > the GFP_DMA flag solves the problem, as the kernel only allocates > > > > 32bit addresses for DMA on rk356x. This is similar to the bug with the > > > > ITS MSI allocations. > > > > > > the problem in this case at least partly seems to be down to the driver > > > assuming 32 bit addresses, see e.g. [1] (if I understand the code > > > correctly) and [2]. When I asked in the #armlinux IRC on Libera.chat > > > about this, Robin Murphy remarked: > > > > > > <robmur01> yeesh, the virt_to_phys/dma_sync abuse is even worse > > > - in that particular instance I'd be inclined to replace > > > {src,dst}_mmu_pages with proper coherent DMA buffers > > > > > > So the driver in general needs some cleanup, which contributes to the > > > problem. > > > > As far as I understand the 4GB are a hardware limitation. > > > > According to the rk3568 TRM, the RGA2_MMU_SRC_BASE has 28 bits for the upper > > 28 bits of the address of the MMU TLB. Thus the MMU TLB must be located within > > 4GB memory. > > > > And within the MMU TLB, the addresses are 32 bit as well (unless I am missing > > something important). Unfortunately, I couldn't find any documentation for the > > TLB. The downstream driver writes only 32 bit addresses to the TLB as well. > > Thus, I assume that all video buffers must be located within 4GB memory, too. > > > > While I agree that the driver needs some cleanup and may use correct types for > > handling the bit size limitation, I think this isn't some driver limitation. > > Maybe the driver should set the dma mask to 32 bits and should be explicitly > > aware of the 32 bit limit. > > > > > > > > But as was said, this isn't a problem with the device tree, so it should > > > still make it in. It just means that the driver is broken on 8GB RK356x. > > Nicolas: Is this your Acked-By? > > Who would pick up the patch? Heiko? > > Michael > Sure, Acked-by: Nicolas Frattaroli <frattaroli.nicolas@xxxxxxxxx> Though I'm not sure how much weight my Acked-by carries here. For applying the patch, yes that would be done by Heiko. Cheers, Nicolas Frattaroli