linux-brain/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dccg.c
Wesley Chalmers c08ecda2cf drm/amd/display: Do not double-buffer DTO adjustments
[ Upstream commit 6bd0a112ec129615d23aa5d8d3dd0be0243989aa ]

[WHY]
When changing DPP global ref clock, DTO adjustments must take effect
immediately, or else underflow may occur.
It appears the original decision to double-buffer DTO adjustments was made to
prevent underflows that occur when raising DPP ref clock (which is not
double-buffered), but that same decision causes similar issues when
lowering DPP global ref clock. The better solution is to order the
adjustments according to whether clocks are being raised or lowered.

Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:17:11 +02:00

162 lines
4.3 KiB
C

/*
* Copyright 2018 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors: AMD
*
*/
#include <linux/slab.h>
#include "reg_helper.h"
#include "core_types.h"
#include "dcn20_dccg.h"
#define TO_DCN_DCCG(dccg)\
container_of(dccg, struct dcn_dccg, base)
#define REG(reg) \
(dccg_dcn->regs->reg)
#undef FN
#define FN(reg_name, field_name) \
dccg_dcn->dccg_shift->field_name, dccg_dcn->dccg_mask->field_name
#define CTX \
dccg_dcn->base.ctx
#define DC_LOGGER \
dccg->ctx->logger
void dccg2_update_dpp_dto(struct dccg *dccg,
int dpp_inst,
int req_dppclk,
bool reduce_divider_only)
{
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
if (dccg->ref_dppclk && req_dppclk) {
int ref_dppclk = dccg->ref_dppclk;
int current_phase, current_modulo;
ASSERT(req_dppclk <= ref_dppclk);
/* need to clamp to 8 bits */
if (ref_dppclk > 0xff) {
int divider = (ref_dppclk + 0xfe) / 0xff;
ref_dppclk /= divider;
req_dppclk = (req_dppclk + divider - 1) / divider;
if (req_dppclk > ref_dppclk)
req_dppclk = ref_dppclk;
}
REG_GET_2(DPPCLK_DTO_PARAM[dpp_inst],
DPPCLK0_DTO_PHASE, &current_phase,
DPPCLK0_DTO_MODULO, &current_modulo);
if (reduce_divider_only) {
// requested phase/modulo greater than current
if (req_dppclk * current_modulo >= current_phase * ref_dppclk) {
REG_SET_2(DPPCLK_DTO_PARAM[dpp_inst], 0,
DPPCLK0_DTO_PHASE, req_dppclk,
DPPCLK0_DTO_MODULO, ref_dppclk);
} else {
REG_SET_2(DPPCLK_DTO_PARAM[dpp_inst], 0,
DPPCLK0_DTO_PHASE, current_phase,
DPPCLK0_DTO_MODULO, current_modulo);
}
} else {
REG_SET_2(DPPCLK_DTO_PARAM[dpp_inst], 0,
DPPCLK0_DTO_PHASE, req_dppclk,
DPPCLK0_DTO_MODULO, ref_dppclk);
}
REG_UPDATE(DPPCLK_DTO_CTRL,
DPPCLK_DTO_ENABLE[dpp_inst], 1);
} else {
REG_UPDATE(DPPCLK_DTO_CTRL,
DPPCLK_DTO_ENABLE[dpp_inst], 0);
}
}
void dccg2_get_dccg_ref_freq(struct dccg *dccg,
unsigned int xtalin_freq_inKhz,
unsigned int *dccg_ref_freq_inKhz)
{
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
uint32_t clk_en = 0;
uint32_t clk_sel = 0;
REG_GET_2(REFCLK_CNTL, REFCLK_CLOCK_EN, &clk_en, REFCLK_SRC_SEL, &clk_sel);
if (clk_en != 0) {
// DCN20 has never been validated for non-xtalin as reference
// frequency. There's actually no way for DC to determine what
// frequency a non-xtalin source is.
ASSERT_CRITICAL(false);
}
*dccg_ref_freq_inKhz = xtalin_freq_inKhz;
return;
}
void dccg2_init(struct dccg *dccg)
{
}
static const struct dccg_funcs dccg2_funcs = {
.update_dpp_dto = dccg2_update_dpp_dto,
.get_dccg_ref_freq = dccg2_get_dccg_ref_freq,
.dccg_init = dccg2_init
};
struct dccg *dccg2_create(
struct dc_context *ctx,
const struct dccg_registers *regs,
const struct dccg_shift *dccg_shift,
const struct dccg_mask *dccg_mask)
{
struct dcn_dccg *dccg_dcn = kzalloc(sizeof(*dccg_dcn), GFP_KERNEL);
struct dccg *base;
if (dccg_dcn == NULL) {
BREAK_TO_DEBUGGER();
return NULL;
}
base = &dccg_dcn->base;
base->ctx = ctx;
base->funcs = &dccg2_funcs;
dccg_dcn->regs = regs;
dccg_dcn->dccg_shift = dccg_shift;
dccg_dcn->dccg_mask = dccg_mask;
return &dccg_dcn->base;
}
void dcn_dccg_destroy(struct dccg **dccg)
{
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(*dccg);
kfree(dccg_dcn);
*dccg = NULL;
}