linux-stable/drivers/gpu/drm/mgag200/mgag200_bmc.c
Thomas Zimmermann 8aeeb3144f drm/mgag200: Provide per-device callbacks for BMC synchronization
Move the BMC-related code into its own file and wire it up with device
callbacks.

While programming a new display mode, G200EW3 and G200WB have to de-
synchronize with the BMC. Synchronization is done via VIDRST pins
and controlled via VRSTEN and HRSTEN bits. Move the BMC code behind
a serviceable interface and call it from the CRTC's enable and
disable functions.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220728124103.30159-11-tzimmermann@suse.de
2022-07-29 16:01:47 +02:00

99 lines
2.1 KiB
C

// 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);
}