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 ? 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
