SAMA5D3 HSMCI: TX DMA is again disabled

arch/arm/src/sama5/sam_hsmci.c

@@ -181,11 +181,17 @@
 #  endif
 #endif
 
-/* These were once helpful.  Perhaps they will be so again some time. */
+/* There is some unresolved issue with the SAMA5D3 DMA.  TX DMA is currently
+ * disabled.
+ */
 
 #undef  HSCMI_NORXDMA            /* Define to disable RX DMA */
 #undef  HSCMI_NOTXDMA            /* Define to disable TX DMA */
 
+#ifdef ATSAMA5D3
+#  define HSCMI_NOTXDMA 1        /* Disabled */
+#endif
+
 /* Timing */
 
 #define HSMCI_CMDTIMEOUT         (100000)

configs/sama5d3-xplained/README.txt

@@ -2824,12 +2824,10 @@ To-Do List
    low priority to me but might be important to you if you are need very
    high performance SD card accesses.
 
-   The last time I used HSMCI with a SAMA5D3, I had to disable TX DMA
+   HCMDI TX DMA is currently disabled for the SAMA5D3.  There is some
-   in the HSMCI driver.  Much has changed since then and I have reverified
+   issue with the TX DMA setup (HSMCI TX DMA the same driver works with
-   that TX DMA transfers are functional using a SAMA5D4.  The SAMA5D4,
+   the SAMA5D4 which has a different DMA subsystem).  This is a bug that
-   however, has a different DMA subsystem.  So... if you suspect issues
+   needs to be resolved.
-   HSMCI writes, you might try disabling the TX DMA again in the
-   sam_hsmci.c driver.
 
 3) GMAC has only been tested on a 10/100Base-T network.  I don't have a
    1000Base-T network to support additional testing.

configs/sama5d3x-ek/README.txt

@@ -3247,7 +3247,7 @@ Configurations
        card slots:  (1) a full size SD card slot (J7 labelled MCI0), and (2)
        a microSD memory card slot (J6 labelled MCI1).  The full size SD card
        slot connects via HSMCI0; the microSD connects vi HSMCI1.  Relevant
-       configuration settings can be found in the section entitle "HSMCI
+       configuration settings can be found in the section entitled "HSMCI
        Card Slots" above.
 
     9. Support the USB high-speed device (UDPHS) driver is enabled.  See the
@@ -3651,12 +3651,10 @@ To-Do List
    low priority to me but might be important to you if you are need very
    high performance SD card accesses.
 
-   The last time I used HSMCI with a SAMA5D3, I had to disable TX DMA
+   HCMDI TX DMA is currently disabled for the SAMA5D3.  There is some
-   in the HSMCI driver.  Much has changed since then and I have reverified
+   issue with the TX DMA setup (HSMCI TX DMA the same driver works with
-   that TX DMA transfers are functional using a SAMA5D4.  The SAMA5D4,
+   the SAMA5D4 which has a different DMA subsystem).  This is a bug that
-   however, has a different DMA subsystem.  So... if you suspect issues
+   needs to be resolved.
-   HSMCI writes, you might try disabling the TX DMA again in the
-   sam_hsmci.c driver.
 
 4) I believe that there is an issue when the internal AT25 FLASH is
    formatted by NuttX.  That format works fine with Linux, but does not