drm/radeon: program auxch directly (v2)

The atombios tables have an unfortunate restriction on only
being able to write 12 bytes, MST really wants 16-bytes here,
and since the hw can do it, we should just write directly to it.

This uses a module option to allow for it now, and maybe
we should provide the old code as a fallback for a while.

v2: (agd5f)
- move registers to a proper register header
- only enable on DCE5+
- enable by default on DCE5+
- Switch pad to aux mode before using it
- reformat instance handling to better match the
  rest of the driver

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/nid.h b/drivers/gpu/drm/radeon/nid.h
index 2e5cdc4..3b29083 100644
--- a/drivers/gpu/drm/radeon/nid.h
+++ b/drivers/gpu/drm/radeon/nid.h
@@ -816,6 +816,52 @@
 #define MC_PMG_CMD_MRS2                                 0x2b5c
 #define MC_SEQ_PMG_CMD_MRS2_LP                          0x2b60
 
+#define AUX_CONTROL					0x6200
+#define 	AUX_EN					(1 << 0)
+#define 	AUX_LS_READ_EN				(1 << 8)
+#define 	AUX_LS_UPDATE_DISABLE(x)		(((x) & 0x1) << 12)
+#define 	AUX_HPD_DISCON(x)			(((x) & 0x1) << 16)
+#define 	AUX_DET_EN				(1 << 18)
+#define 	AUX_HPD_SEL(x)				(((x) & 0x7) << 20)
+#define 	AUX_IMPCAL_REQ_EN			(1 << 24)
+#define 	AUX_TEST_MODE				(1 << 28)
+#define 	AUX_DEGLITCH_EN				(1 << 29)
+#define AUX_SW_CONTROL					0x6204
+#define 	AUX_SW_GO				(1 << 0)
+#define 	AUX_LS_READ_TRIG			(1 << 2)
+#define 	AUX_SW_START_DELAY(x)			(((x) & 0xf) << 4)
+#define 	AUX_SW_WR_BYTES(x)			(((x) & 0x1f) << 16)
+
+#define AUX_SW_INTERRUPT_CONTROL			0x620c
+#define 	AUX_SW_DONE_INT				(1 << 0)
+#define 	AUX_SW_DONE_ACK				(1 << 1)
+#define 	AUX_SW_DONE_MASK			(1 << 2)
+#define 	AUX_SW_LS_DONE_INT			(1 << 4)
+#define 	AUX_SW_LS_DONE_MASK			(1 << 6)
+#define AUX_SW_STATUS					0x6210
+#define 	AUX_SW_DONE				(1 << 0)
+#define 	AUX_SW_REQ				(1 << 1)
+#define 	AUX_SW_RX_TIMEOUT_STATE(x)		(((x) & 0x7) << 4)
+#define 	AUX_SW_RX_TIMEOUT			(1 << 7)
+#define 	AUX_SW_RX_OVERFLOW			(1 << 8)
+#define 	AUX_SW_RX_HPD_DISCON			(1 << 9)
+#define 	AUX_SW_RX_PARTIAL_BYTE			(1 << 10)
+#define 	AUX_SW_NON_AUX_MODE			(1 << 11)
+#define 	AUX_SW_RX_MIN_COUNT_VIOL		(1 << 12)
+#define 	AUX_SW_RX_INVALID_STOP			(1 << 14)
+#define 	AUX_SW_RX_SYNC_INVALID_L		(1 << 17)
+#define 	AUX_SW_RX_SYNC_INVALID_H		(1 << 18)
+#define 	AUX_SW_RX_INVALID_START			(1 << 19)
+#define 	AUX_SW_RX_RECV_NO_DET			(1 << 20)
+#define 	AUX_SW_RX_RECV_INVALID_H		(1 << 22)
+#define 	AUX_SW_RX_RECV_INVALID_V		(1 << 23)
+
+#define AUX_SW_DATA					0x6218
+#define AUX_SW_DATA_RW					(1 << 0)
+#define AUX_SW_DATA_MASK(x)				(((x) & 0xff) << 8)
+#define AUX_SW_DATA_INDEX(x)				(((x) & 0x1f) << 16)
+#define AUX_SW_AUTOINCREMENT_DISABLE			(1 << 31)
+
 #define	LB_SYNC_RESET_SEL				0x6b28
 #define		LB_SYNC_RESET_SEL_MASK			(3 << 0)
 #define		LB_SYNC_RESET_SEL_SHIFT			0