Prabhakar, On 3/30/2020 6:39 PM, Lad, Prabhakar wrote: > Hi Kishon, > > On Mon, Mar 30, 2020 at 12:59 PM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >> >> Hi Prabhakar, >> >> On 3/29/2020 7:34 PM, Lad, Prabhakar wrote: >>> Hi Kishon, >>> >>> On Sat, Mar 28, 2020 at 6:44 PM Lad, Prabhakar >>> <prabhakar.csengg@xxxxxxxxx> wrote: >>>> >>>> Hi Kishon, >>>> >>>> On Tue, Mar 24, 2020 at 2:41 PM Lad, Prabhakar >>>> <prabhakar.csengg@xxxxxxxxx> wrote: >>>>> >>>>> Hi Kishon, >>>>> >>>>> On Tue, Mar 24, 2020 at 1:58 AM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >>>>>> >>>>>> Hi Prabhakar, >>>>>> >>>>>> On 3/22/2020 4:19 AM, Lad, Prabhakar wrote: >>>>>>> Hi Kishon, >>>>>>> >>>>>>> On Fri, Mar 20, 2020 at 5:28 AM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: >>>>>>>> >>>>>>>> Hi Prabhakar, >>>>>>>> >>>>>>>> On 3/18/2020 5:07 PM, Lad, Prabhakar wrote: >>>>>>>>> Hi Kishon, >>>>>>>>> >>>>>>>>> I rebased my rcar-endpoint patches on endpoint branch, which has >>>>>>>>> support for streaming DMA API support, with this read/write/copy >>>>>>>>> tests failed, to make sure nothing hasn't changed on my driver I >>>>>>>>> reverted the streaming DMA API patch >>>>>>>>> 74b9b4da84c71418ceeaaeb78dc790376df92fea "misc: pci_endpoint_test: Use >>>>>>>>> streaming DMA APIs for buffer allocation" and tests began to pass >>>>>>>>> again. >>>>>>>>> >>>>>>>>> If add a GFP_DMA flag for kzalloc (with streaming DMA), the test cases >>>>>>>>> for read/write/copy pass as expected. >>>>>>>>> >>>>>>>>> Could you please through some light why this could be happening. >>>>>>>> >>>>>>>> Do you see any differences in the address returned by dma_map_single() like is >>>>>>>> it 32-bit address or 64-bit address? >>>>>>>> >>>>>>> Both return 32 bit address, debugging further I see that with >>>>>>> GFP_KERNEL flag for small buffer >>>>>>> sizes the read/write/copy tests pass(upto 4k), so I am suspecting its >>>>>>> related to caching probably. >>>>>>> Also adding wmb()/rmb() just with GFP_KERNEL flag didn't help. Note I >>>>>>> am using PIO transfers. >>>>>>> Any thoughts on how we tackle it ? >>>>>>> >>>>>>> # With GFP_KERNEL flag >>>>>>> root@hihope-rzg2m:~# pcitest -r >>>>>>> [ 46.210649] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff0004b4ae0000 dma:7e99d000 align:ffff0004b4ae0000 >>>>>>> READ ( 102400 bytes): NOT OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r >>>>>>> [ 51.880063] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff0004b4ae0000 dma:7e9c0000 align:ffff0004b4ae0000 >>>>>>> READ ( 102400 bytes): OKAY >>>>>> >>>>>> Here one of the read test is passing and the other is failing. >>>>>> For the 1st case dma:7e99d000, address is aligned to 4K >>>>>> For the 2nd case dma:7e9c0000, address is aligned to 256K >>>>>> >>>>>> I'm suspecting this could be an alignment issue. Does the outbound ATU of your >>>>>> EP has any restrictions? (like the address should be aligned to the size?). >>>>>> >>>>> There isn't any restriction for outbound ATU on ep, Although I tried >>>>> alignment from >>>>> SZ_1 - SZ_256K and each failed at several points. >>>>> >>>>> With GFP_KERNEL | GFP_DMA, as in my previous dump here the address too >>>>> is not aligned to 256 but still read passes. >>>>> root@hihope-rzg2m:~# pcitest -r -s 16384 >>>>> [ 186.629347] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>> kzalloc:ffff00003b848000 dma:7b848000 align:ffff00003b848000 >>>>> READ ( 16384 bytes): OKAY >>>>> >>>>> And I have verified with GFP_KERNEL | GFP_DMA on my platform >>>>> everything works as expected, >>>>> >>>>> So how about a patch for pci_endpoint_test.c, where flags are passed >>>>> as part of driver_data and it defaults to just GFP_KERNEL ? >>>>> >>>> Any thoughts on the above ? I intended to get the endpoint driver for v5.7. >>>> >>> Correct me if I am wrong here, streaming DMA API should be used with >>> dma (-d) option so that root device >>> makes sure the data is synced when data is transferred whereas >>> previously with dma_alloc_coherent() >>> we didn't have to care about cache issues. Also for a non-dma (-d) >>> option we don't have a handle to dma >>> in rootpport device so that we can call a sync operation. I say this >>> because on my platform with streaming >>> DMA api it works for small size buffers but it doesn't work with large >>> size buffers. >> >> Streaming DMA API and DMA support in endpoint can be treated independently. >> dma_alloc_coherent() will give you coherent memory, so you don't have to flush >> or invalidate. This memory is usually limited in a platform. >> The other option was to use streaming DMA APIs which doesn't give coherent >> memory but SW has to take care of flush and invalidate. >> > Agreed. But we don't flush in SW when -d option is not specified I am > assuming when we us > -d dma engine takes care of flushing it. The -d option switch doesn't change anything on the SW that runs on the host side (misc/pci-endpoint-test.c). That only tells the EP to use DMA. When you use streaming APIs, dma_map_single(), dmap_unmap_single() takes care of flushing or invalidating memory based on the platform. (Platforms which have coherent memory will have dma-coherent property, dma_map_single()/dmap_unmap_single() will not do flush or invalidate. Did you try to probe the failure further by comparing the hexdumps? Where does the mismatch happen? > >>> >>> Could you please confirm with streaming DMA api without DMA (-d) >>> option for large buffers read/write/copy >>> still passes for you. >> >> root@j7-evm:~# ./pcitest -r >> READ ( 102400 bytes): OKAY >> root@j7-evm:~# ./pcitest -r -s 1024000 >> READ (1024000 bytes): OKAY >> root@j7-evm:~# ./pcitest -w -s 1024000 >> WRITE (1024000 bytes): OKAY >> root@j7-evm:~# ./pcitest -c -s 1024000 >> COPY (1024000 bytes): OKAY >> root@j7-evm:~# ./pcitest -c -s 10240000 >> COPY (10240000 bytes): OKAY >> root@j7-evm:~# ./pcitest -r -s 10240000 >> READ (10240000 bytes): OKAY >> root@j7-evm:~# ./pcitest -w -s 10240000 >> WRITE (10240000 bytes): OKAY > > Thank you for testing is this on Jacinto ? > >>> >>> Although I am not sure why adding GFP_KERNEL | GFP_DMA flag for >>> kzalloc on my platform fixes everything. >> >> Which host do you use? If this is only a host side limitation, you could try >> using a different host. >> > I am trying this on Renesas RZ/G2N as host and RZ/G2E as an endpoint. > ATM I can only test this on > Renesas platforms only and all of them have same PCIe controller :( Does the host controller work well with other standard PCIe cards (NVMe, USB etc.,)? > > How about adding flags as part of driver data and defaulting it GFP_KERNEL ? Nope. Not before we clearly understand the reason for the failure. Thanks Kishon > > Cheers, > --Prabhakar > >> Thanks >> Kishon >> >>> >>> Cheers, >>> --Prabhakar >>> >>> >>>> Cheers, >>>> --Prabhakar >>>> >>>>> Cheers, >>>>> --Prabhakar >>>>> >>>>>> Thanks >>>>>> Kishon >>>>>> >>>>>>> root@hihope-rzg2m:~# pcitest -r >>>>>>> [ 53.354830] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff0004b4ae0000 dma:7e9e2000 align:ffff0004b4ae0000 >>>>>>> READ ( 102400 bytes): NOT OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r >>>>>>> [ 55.307236] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff0004b4ae0000 dma:7ea04000 align:ffff0004b4ae0000 >>>>>>> READ ( 102400 bytes): NOT OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r >>>>>>> [ 57.098626] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff0004b4ae0000 dma:7ea23000 align:ffff0004b4ae0000 >>>>>>> READ ( 102400 bytes): NOT OKAY >>>>>>> >>>>>>> # GFP_KERNEL | GFP_DMA >>>>>>> >>>>>>> root@hihope-rzg2m:~# pcitest -r -s 1024001 >>>>>>> [ 174.562071] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff00003b900000 dma:7b900000 align:ffff00003b900000 >>>>>>> READ (1024001 bytes): OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r -s 16384 >>>>>>> [ 186.629347] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff00003b848000 dma:7b848000 align:ffff00003b848000 >>>>>>> READ ( 16384 bytes): OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r -s 8192 >>>>>>> [ 190.578335] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff00003b840000 dma:7b840000 align:ffff00003b840000 >>>>>>> READ ( 8192 bytes): OKAY >>>>>>> root@hihope-rzg2m:~# pcitest -r -s 128 >>>>>>> [ 199.428021] pci-endpoint-test 0000:01:00.0: pci_endpoint_test_read >>>>>>> kzalloc:ffff00003b800000 dma:7b800000 align:ffff00003b800000 >>>>>>> READ ( 128 bytes): OKAY >>>>>>> root@hihope-rzg2m:~# >>>>>>> >>>>>>> Cheers, >>>>>>> --Prabhakar >>>>>>> >>>>>>>> Thanks >>>>>>>> Kishon
