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bcm, bcm64: fix cache operations for dma and emmc

always clean AND invalidate caches before dma read,
never just invalidate as the buffer might not be
aligned to cache lines...

we have to invalidate caches again *AFTER* the dma
read has completed. the processor can bring in data
speculatively into the cache while the dma in in
flight.

--- a/sys/src/9/bcm/dma.c

+++ b/sys/src/9/bcm/dma.c

@@ -170,7 +170,7 @@

 	ti = 0;

 	switch(dir){

 	case DmaD2M:

-		cachedinvse(dst, len);

+		cachedwbinvse(dst, len);

 		ti = Srcdreq | Destinc;

 		cb->sourcead = dmaioaddr(src);

 		cb->destad = dmaaddr(dst);

@@ -183,7 +183,7 @@

 		break;

 	case DmaM2M:

 		cachedwbse(src, len);

-		cachedinvse(dst, len);

+		cachedwbinvse(dst, len);

 		ti = Srcinc | Destinc;

 		cb->sourcead = dmaaddr(src);

 		cb->destad = dmaaddr(dst);

--- a/sys/src/9/bcm/emmc.c

+++ b/sys/src/9/bcm/emmc.c

@@ -398,6 +398,8 @@

 	}

 	if(i)

 		WR(Interrupt, i);

+	if(!write)

+		cachedinvse(buf, len);

 	poperror();

 	okay(0);

 }

-- 

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