/*
* Copyright 2014 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.
*
*/
#include <drm/amdgpu_drm.h>
#include "amdgpu.h"
#include "atom.h"
#include "atombios_encoders.h"
#include "amdgpu_pll.h"
#include <asm/div64.h>
#include <linux/gcd.h>
/**
* amdgpu_pll_reduce_ratio - fractional number reduction
*
* @nom: nominator
* @den: denominator
* @nom_min: minimum value for nominator
* @den_min: minimum value for denominator
*
* Find the greatest common divisor and apply it on both nominator and
* denominator, but make nominator and denominator are at least as large
* as their minimum values.
*/
static void amdgpu_pll_reduce_ratio(unsigned *nom, unsigned *den,
unsigned nom_min, unsigned den_min)
{
unsigned tmp;
/* reduce the numbers to a simpler ratio */
tmp = gcd(*nom, *den);
*nom /= tmp;
*den /= tmp;
/* make sure nominator is large enough */
if (*nom < nom_min) {
tmp = DIV_ROUND_UP(nom_min, *nom);
*nom *= tmp;
*den *= tmp;
}
/* make sure the denominator is large enough */
if (*den < den_min) {
tmp = DIV_ROUND_UP(den_min, *den);
*nom *= tmp;
*den *= tmp;
}
}
/**
* amdgpu_pll_get_fb_ref_div - feedback and ref divider calculation
*
* @nom: nominator
* @den: denominator
* @post_div: post divider
* @fb_div_max: feedback divider maximum
* @ref_div_max: reference divider maximum
* @fb_div: resulting feedback divider
* @ref_div: resulting reference divider
*
* Calculate feedback and reference divider for a given post divider. Makes
* sure we stay within the limits.
*/
static void amdgpu_pll_get_fb_ref_div(unsigned nom, unsigned den, unsigned post_div,
unsigned fb_div_max, unsigned ref_div_max,
unsigned *fb_div, unsigned *ref_div)
{
/* limit reference * post divider to a maximum */
ref_div_max = min(128 / post_div, ref_div_max);
/* get matching reference and feedback divider */
*ref_div = min(max(DIV_ROUND_CLOSEST(den, post_div), 1u), ref_div_max);
*fb_div = DIV_ROUND_CLOSEST(nom * *ref_div * post_div, den);
/* limit fb divider to its maximum */
if (*fb_div > fb_div_max) {
*ref_div = DIV_ROUND_CLOSEST(*ref_div * fb_div_max, *fb_div);
*fb_div = fb_div_max;
}
}
/**
* amdgpu_pll_compute - compute PLL paramaters
*
* @pll: information about the PLL
* @freq: requested frequency
* @dot_clock_p: resulting pixel clock
* @fb_div_p: resulting feedback divider
* @frac_fb_div_p: fractional part of the feedback divider
* @ref_div_p: resulting reference divider
* @post_div_p: resulting reference divider
*
* Try to calculate the PLL parameters to generate the given frequency:
* dot_clock = (ref_freq * feedback_div) / (ref_div * post_div)
*/
void amdgpu_pll_compute(struct amdgpu_pll *pll,
u32 freq,
u32 *dot_clock_p,
u32 *fb_div_p,
u32 *frac_fb_div_p,
u32 *ref_div_p,
u32 *post_div_p)
{
unsigned target_clock = pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV ?
freq : freq / 10;
unsigned fb_div_min, fb_div_max, fb_div;
unsigned post_div_min, post_div_max, post_div;
unsigned ref_div_min, ref_div_max, ref_div;
unsigned post_div_best, diff_best;
unsigned nom, den;
/* determine allowed feedback divider range */
fb_div_min = pll->min_feedback_div;
fb_div_max = pll->max_feedback_div;
if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
fb_div_min *= 10;
fb_div_max *= 10;
}
/* determine allowed ref divider range */
if (pll->flags & AMDGPU_PLL_USE_REF_DIV)
ref_div_min = pll->reference_div;
else
ref_div_min = pll->min_ref_div;
if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV &&
pll->flags & AMDGPU_PLL_USE_REF_DIV)
ref_div_max = pll->reference_div;
else
ref_div_max = pll->max_ref_div;
/* determine allowed post divider range */
if (pll->flags & AMDGPU_PLL_USE_POST_DIV) {
post_div_min = pll->post_div;
post_div_max = pll->post_div;
} else {
unsigned vco_min, vco_max;
if (pll->flags & AMDGPU_PLL_IS_LCD) {
vco_min = pll->lcd_pll_out_min;
vco_max = pll->lcd_pll_out_max;
} else {
vco_min = pll->pll_out_min;
vco_max = pll->pll_out_max;
}
if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
vco_min *= 10;
vco_max *= 10;
}
post_div_min = vco_min / target_clock;
if ((target_clock * post_div_min) < vco_min)
++post_div_min;
if (post_div_min < pll->min_post_div)
post_div_min = pll->min_post_div;
post_div_max = vco_max / target_clock;
if ((target_clock * post_div_max) > vco_max)
--post_div_max;
if (post_div_max > pll->max_post_div)
post_div_max = pll->max_post_div;
}
/* represent the searched ratio as fractional number */
nom = target_clock;
den = pll->reference_freq;
/* reduce the numbers to a simpler ratio */
amdgpu_pll_reduce_ratio(&nom, &den, fb_div_min, post_div_min);
/* now search for a post divider */
if (pll->flags & AMDGPU_PLL_PREFER_MINM_OVER_MAXP)
post_div_best = post_div_min;
else
post_div_best = post_div_max;
diff_best = ~0;
for (post_div = post_div_min; post_div <= post_div_max; ++post_div) {
unsigned diff;
amdgpu_pll_get_fb_ref_div(nom, den, post_div, fb_div_max,
ref_div_max, &fb_div, &ref_div);
diff = abs(target_clock - (pll->reference_freq * fb_div) /
(ref_div * post_div));
if (diff < diff_best || (diff == diff_best &&
!(pll->flags & AMDGPU_PLL_PREFER_MINM_OVER_MAXP))) {
post_div_best = post_div;
diff_best = diff;
}
}
post_div = post_div_best;
/* get the feedback and reference divider for the optimal value */
amdgpu_pll_get_fb_ref_div(nom, den, post_div, fb_div_max, ref_div_max,
&fb_div, &ref_div);
/* reduce the numbers to a simpler ratio once more */
/* this also makes sure that the reference divider is large enough */
amdgpu_pll_reduce_ratio(&fb_div, &ref_div, fb_div_min, ref_div_min);
/* avoid high jitter with small fractional dividers */
if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV && (fb_div % 10)) {
fb_div_min = max(fb_div_min, (9 - (fb_div % 10)) * 20 + 60);
if (fb_div < fb_div_min) {
unsigned tmp = DIV_ROUND_UP(fb_div_min, fb_div);
fb_div *= tmp;
ref_div *= tmp;
}
}
/* and finally save the result */
if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
*fb_div_p = fb_div / 10;
*frac_fb_div_p = fb_div % 10;
} else {
*fb_div_p = fb_div;
*frac_fb_div_p = 0;
}
*dot_clock_p = ((pll->reference_freq * *fb_div_p * 10) +
(pll->reference_freq * *frac_fb_div_p)) /
(ref_div * post_div * 10);
*ref_div_p = ref_div;
*post_div_p = post_div;
DRM_DEBUG_KMS("%d - %d, pll dividers - fb: %d.%d ref: %d, post %d\n",
freq, *dot_clock_p * 10, *fb_div_p, *frac_fb_div_p,
ref_div, post_div);
}
/**
* amdgpu_pll_get_use_mask - look up a mask of which pplls are in use
*
* @crtc: drm crtc
*
* Returns the mask of which PPLLs (Pixel PLLs) are in use.
*/
u32 amdgpu_pll_get_use_mask(struct drm_crtc *crtc)
{
struct drm_device *dev = crtc->dev;
struct drm_crtc *test_crtc;
struct amdgpu_crtc *test_amdgpu_crtc;
u32 pll_in_use = 0;
list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
if (crtc == test_crtc)
continue;
test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
pll_in_use |= (1 << test_amdgpu_crtc->pll_id);
}
return pll_in_use;
}
/**
* amdgpu_pll_get_shared_dp_ppll - return the PPLL used by another crtc for DP
*
* @crtc: drm crtc
*
* Returns the PPLL (Pixel PLL) used by another crtc/encoder which is
* also in DP mode. For DP, a single PPLL can be used for all DP
* crtcs/encoders.
*/
int amdgpu_pll_get_shared_dp_ppll(struct drm_crtc *crtc)
{
struct drm_device *dev = crtc->dev;
struct drm_crtc *test_crtc;
struct amdgpu_crtc *test_amdgpu_crtc;
list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
if (crtc == test_crtc)
continue;
test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
if (test_amdgpu_crtc->encoder &&
ENCODER_MODE_IS_DP(amdgpu_atombios_encoder_get_encoder_mode(test_amdgpu_crtc->encoder))) {
/* for DP use the same PLL for all */
if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
return test_amdgpu_crtc->pll_id;
}
}
return ATOM_PPLL_INVALID;
}
/**
* amdgpu_pll_get_shared_nondp_ppll - return the PPLL used by another non-DP crtc
*
* @crtc: drm crtc
*
* Returns the PPLL (Pixel PLL) used by another non-DP crtc/encoder which can
* be shared (i.e., same clock).
*/
int amdgpu_pll_get_shared_nondp_ppll(struct drm_crtc *crtc)
{
struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
struct drm_device *dev = crtc->dev;
struct drm_crtc *test_crtc;
struct amdgpu_crtc *test_amdgpu_crtc;
u32 adjusted_clock, test_adjusted_clock;
adjusted_clock = amdgpu_crtc->adjusted_clock;
if (adjusted_clock == 0)
return ATOM_PPLL_INVALID;
list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
if (crtc == test_crtc)
continue;
test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
if (test_amdgpu_crtc->encoder &&
!ENCODER_MODE_IS_DP(amdgpu_atombios_encoder_get_encoder_mode(test_amdgpu_crtc->encoder))) {
/* check if we are already driving this connector with another crtc */
if (test_amdgpu_crtc->connector == amdgpu_crtc->connector) {
/* if we are, return that pll */
if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
return test_amdgpu_crtc->pll_id;
}
/* for non-DP check the clock */
test_adjusted_clock = test_amdgpu_crtc->adjusted_clock;
if ((crtc->mode.clock == test_crtc->mode.clock) &&
(adjusted_clock == test_adjusted_clock) &&
(amdgpu_crtc->ss_enabled == test_amdgpu_crtc->ss_enabled) &&
(test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID))
return test_amdgpu_crtc->pll_id;
}
}
return ATOM_PPLL_INVALID;
}
