// SPDX-License-Identifier: GPL-2.0-only
#include <linux/delay.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_managed.h>
#include <drm/drm_probe_helper.h>
#include "mgag200_drv.h"
void mgag200_bmc_stop_scanout(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_start_scanout(struct mga_device *mdev)
{
u8 tmp;
/* 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);
}