Jun Lei f7f38ffef5 drm/amd/display: fixup DPP programming sequence
[why]
DC does not correct account for the fact that DPP DTO is double buffered while DPP ref is not.
This means that when DPP ref clock is lowered when it's "safe to lower", the DPP blocks that need
an increased divider will temporarily have actual DPP clock drop below minimum while DTO
double buffering takes effect.  This results in temporary underflow.

[how]
To fix this, DPP clock cannot be programmed atomically, but rather be broken up into the DTO and the
ref.  Each has a separate "safe to lower" logic.  When doing "prepare" the ref and dividers may only increase.
When doing "optimize", both may decrease.  It is guaranteed that we won't exceed max DPP clock because
we do not use dividers larger than 1.

Signed-off-by: Jun Lei <Jun.Lei@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2019-08-15 10:53:43 -05:00

188 lines
4.9 KiB
C

/*
* Copyright 2018 Advanced Micro Devices, Inc.
*
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* The above copyright notice and this permission notice shall be included in
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*
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* Authors: AMD
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*/
#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)
{
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
// Fallthrough intentional to program all available dpp_dto's
switch (dccg_dcn->base.ctx->dc->res_pool->pipe_count) {
case 6:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[5], 1);
/* Fall through */
case 5:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[4], 1);
/* Fall through */
case 4:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[3], 1);
/* Fall through */
case 3:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[2], 1);
/* Fall through */
case 2:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[1], 1);
/* Fall through */
case 1:
REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_DB_EN[0], 1);
break;
default:
ASSERT(false);
break;
}
}
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;
}