RPi4B 3 GiByte pcie limitation: The following change survived my huge-file duplicate-and-diff tests so far
Mark Millard via freebsd-arm <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
It appears to me that 3 GiByte works for lowaddr and maxsize but that the maxsegsz needs to be limited to 1 GiByte [or so, maybe (1 Gi - 1) Bytes]. I did the following based on all those notes that I sent out, that included the ?_TXFR_LEN being limited 30 bits for (normal) DMA engines (0-6) and the DMA4 engines (11-14) [but not DMA LITE (7-10)]: # svnlite diff /usr/src/sys/arm/broadcom/bcm2835/bcm2838_pci.c /usr/src/sys/arm/broadcom/bcm2835/bcm2838_xhci.c Index: /usr/src/sys/arm/broadcom/bcm2835/bcm2838_pci.c =================================================================== --- /usr/src/sys/arm/broadcom/bcm2835/bcm2838_pci.c (revision 365932) +++ /usr/src/sys/arm/broadcom/bcm2835/bcm2838_pci.c (working copy) @@ -105,7 +105,8 @@ * * Whatever the true maximum address, 960 MiB works. */ -#define DMA_HIGH_LIMIT 0x3c000000 +#define DMA_SEG_HIGH_LIMIT 0x3c000000 +#define DMA_TOTAL_HIGH_LIMIT 0xc0000000 #define MAX_MEMORY_LOG2 0x21 #define REG_VALUE_DMA_WINDOW_LOW (MAX_MEMORY_LOG2 - 0xf) #define REG_VALUE_DMA_WINDOW_HIGH 0x0 @@ -642,12 +643,12 @@ */ error = bus_dma_tag_create(bus_get_dma_tag(dev), /* parent */ 1, 0, /* alignment, bounds */ - DMA_HIGH_LIMIT, /* lowaddr */ + DMA_TOTAL_HIGH_LIMIT, /* lowaddr */ BUS_SPACE_MAXADDR, /* highaddr */ NULL, NULL, /* filter, filterarg */ - DMA_HIGH_LIMIT, /* maxsize */ + DMA_TOTAL_HIGH_LIMIT, /* maxsize */ BUS_SPACE_UNRESTRICTED, /* nsegments */ - DMA_HIGH_LIMIT, /* maxsegsize */ + DMA_SEG_HIGH_LIMIT, /* maxsegsize */ 0, /* flags */ NULL, NULL, /* lockfunc, lockarg */ &sc->dmat); Then, with such a kernel installed, I used: -rw-r--r-- 1 root wheel 11570948096 Jul 18 18:32:37 2020 clang-armv7-on-aarch64.tar (so much larger than the 8 GiByte RAM) and did the following with the file: # cp -aRx clang-armv7-on-aarch64.tar clang-armv7-on-aarch64.alt_tar # diff clang-armv7-on-aarch64.tar clang-armv7-on-aarch64.alt_tar # Such tests have been passing. I do not know what your test procedures were. But if the above is suggestive, you might want to try testing something like the above via your test procedures. === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar) _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-arm To unsubscribe, send any mail to "[email protected]"