1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/gpu/drm/mgag200/mgag200_bmc.c b/drivers/gpu/drm/mgag200/mgag200_bmc.c
new file mode 100644
index 000000000000..2ba2e3c5086a
--- /dev/null
+++ b/drivers/gpu/drm/mgag200/mgag200_bmc.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/delay.h>
+
+#include "mgag200_drv.h"
+
+void mgag200_bmc_disable_vidrst(struct mga_device *mdev)
+{
+	u8 tmp;
+	int iter_max;
+
+	/*
+	 * 1 - The first step is to inform the BMC of an upcoming mode
+	 * change. We are putting the misc<0> to output.
+	 */
+
+	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
+	tmp = RREG8(DAC_DATA);
+	tmp |= 0x10;
+	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);
+
+	/* we are putting a 1 on the misc<0> line */
+	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
+	tmp = RREG8(DAC_DATA);
+	tmp |= 0x10;
+	WREG_DAC(MGA1064_GEN_IO_DATA, tmp);
+
+	/*
+	 * 2- Second step to mask any further scan request. This is
+	 * done by asserting the remfreqmsk bit (XSPAREREG<7>)
+	 */
+
+	WREG8(DAC_INDEX, MGA1064_SPAREREG);
+	tmp = RREG8(DAC_DATA);
+	tmp |= 0x80;
+	WREG_DAC(MGA1064_SPAREREG, tmp);
+
+	/*
+	 * 3a- The third step is to verify if there is an active scan.
+	 * We are waiting for a 0 on remhsyncsts <XSPAREREG<0>).
+	 */
+	iter_max = 300;
+	while (!(tmp & 0x1) && iter_max) {
+		WREG8(DAC_INDEX, MGA1064_SPAREREG);
+		tmp = RREG8(DAC_DATA);
+		udelay(1000);
+		iter_max--;
+	}
+
+	/*
+	 * 3b- This step occurs only if the remove is actually
+	 * scanning. We are waiting for the end of the frame which is
+	 * a 1 on remvsyncsts (XSPAREREG<1>)
+	 */
+	if (iter_max) {
+		iter_max = 300;
+		while ((tmp & 0x2) && iter_max) {
+			WREG8(DAC_INDEX, MGA1064_SPAREREG);
+			tmp = RREG8(DAC_DATA);
+			udelay(1000);
+			iter_max--;
+		}
+	}
+}
+
+void mgag200_bmc_enable_vidrst(struct mga_device *mdev)
+{
+	u8 tmp;
+
+	/* Ensure that the vrsten and hrsten are set */
+	WREG8(MGAREG_CRTCEXT_INDEX, 1);
+	tmp = RREG8(MGAREG_CRTCEXT_DATA);
+	WREG8(MGAREG_CRTCEXT_DATA, tmp | 0x88);
+
+	/* Assert rstlvl2 */
+	WREG8(DAC_INDEX, MGA1064_REMHEADCTL2);
+	tmp = RREG8(DAC_DATA);
+	tmp |= 0x8;
+	WREG8(DAC_DATA, tmp);
+
+	udelay(10);
+
+	/* Deassert rstlvl2 */
+	tmp &= ~0x08;
+	WREG8(DAC_INDEX, MGA1064_REMHEADCTL2);
+	WREG8(DAC_DATA, tmp);
+
+	/* Remove mask of scan request */
+	WREG8(DAC_INDEX, MGA1064_SPAREREG);
+	tmp = RREG8(DAC_DATA);
+	tmp &= ~0x80;
+	WREG8(DAC_DATA, tmp);
+
+	/* Put back a 0 on the misc<0> line */
+	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
+	tmp = RREG8(DAC_DATA);
+	tmp &= ~0x10;
+	WREG_DAC(MGA1064_GEN_IO_DATA, tmp);
+}