[GitHub] [mynewt-core] andrzej-kaczmarek commented on a change in pull request #2392: da1469x: Fix DMA Multiplexer register access

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andrzej-kaczmarek commented on a change in pull request #2392:
URL: https://github.com/apache/mynewt-core/pull/2392#discussion_r507747562



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File path: hw/drivers/crypto/crypto_da1469x/src/crypto_da1469x.c
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@@ -73,7 +74,10 @@ do_dma_key_tx(const void *key, uint16_t keylen)
     da1469x_otp_set_mode(OTPC_MODE_READ);
 
     /* securely DMA hardware key from secret storage to QSPI decrypt engine */
-    dma_regs->DMA_REQ_MUX_REG |= 0xf000;
+    OS_ENTER_CRITICAL(sr);
+    /* Use the secure channel #7 */
+    MCU_DMA_SET_MUX(7, MCU_DMA_PERIPH_NONE);

Review comment:
       > I do think the macro should remain local and `da1469x_dma_acquire_xxx()` and `da1469x_dma_release_channel()` should be used instead of accessing `DMA_REQ_MUX_REG` directly (e.g. crypto driver should use these calls for channel 7 with the macro fixed).
   
   agree, acquire/release should be used since it also keeps track of used channels internally. if some pieces of code manually modify mux register, things may not works as expected... so if there's something that acquire/release does not do it should be fixed there




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