iommu/dart: Initialize DART_STREAMS_ENABLE

DART has an additional global register to control which streams are
isolated. This register is a bit redundant since DART_TCR can already
be used to control isolation and is usually initialized to DART_STREAM_ALL
by the time we get control. Some DARTs (namely the one used for the audio
controller) however have some streams disabled initially. Make sure those
work by initializing DART_STREAMS_ENABLE during reset.
Reported-by: Martin Povišer <povik@protonmail.com>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Reviewed-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20211019162253.45919-1-sven@svenpeter.devSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/apple-dart.c

@@ -70,6 +70,8 @@
 #define DART_ERROR_ADDR_HI 0x54
 #define DART_ERROR_ADDR_LO 0x50
 
+#define DART_STREAMS_ENABLE 0xfc
+
 #define DART_TCR(sid) (0x100 + 4 * (sid))
 #define DART_TCR_TRANSLATE_ENABLE BIT(7)
 #define DART_TCR_BYPASS0_ENABLE BIT(8)
@@ -301,6 +303,9 @@ static int apple_dart_hw_reset(struct apple_dart *dart)
 	apple_dart_hw_disable_dma(&stream_map);
 	apple_dart_hw_clear_all_ttbrs(&stream_map);
 
+	/* enable all streams globally since TCR is used to control isolation */
+	writel(DART_STREAM_ALL, dart->regs + DART_STREAMS_ENABLE);
+
 	/* clear any pending errors before the interrupt is unmasked */
 	writel(readl(dart->regs + DART_ERROR), dart->regs + DART_ERROR);