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. > > 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 > > 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. 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
