cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sun4i_hdmi_ddc_clk.c (3123B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Copyright (C) 2016 Free Electrons
      4 * Copyright (C) 2016 NextThing Co
      5 *
      6 * Maxime Ripard <maxime.ripard@free-electrons.com>
      7 */
      8
      9#include <linux/clk-provider.h>
     10#include <linux/regmap.h>
     11
     12#include "sun4i_hdmi.h"
     13
     14struct sun4i_ddc {
     15	struct clk_hw		hw;
     16	struct sun4i_hdmi	*hdmi;
     17	struct regmap_field	*reg;
     18	u8			pre_div;
     19	u8			m_offset;
     20};
     21
     22static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
     23{
     24	return container_of(hw, struct sun4i_ddc, hw);
     25}
     26
     27static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
     28					    unsigned long parent_rate,
     29					    const u8 pre_div,
     30					    const u8 m_offset,
     31					    u8 *m, u8 *n)
     32{
     33	unsigned long best_rate = 0;
     34	u8 best_m = 0, best_n = 0, _m, _n;
     35
     36	for (_m = 0; _m < 16; _m++) {
     37		for (_n = 0; _n < 8; _n++) {
     38			unsigned long tmp_rate;
     39
     40			tmp_rate = (((parent_rate / pre_div) / 10) >> _n) /
     41				(_m + m_offset);
     42
     43			if (tmp_rate > rate)
     44				continue;
     45
     46			if (abs(rate - tmp_rate) < abs(rate - best_rate)) {
     47				best_rate = tmp_rate;
     48				best_m = _m;
     49				best_n = _n;
     50			}
     51		}
     52	}
     53
     54	if (m && n) {
     55		*m = best_m;
     56		*n = best_n;
     57	}
     58
     59	return best_rate;
     60}
     61
     62static long sun4i_ddc_round_rate(struct clk_hw *hw, unsigned long rate,
     63				 unsigned long *prate)
     64{
     65	struct sun4i_ddc *ddc = hw_to_ddc(hw);
     66
     67	return sun4i_ddc_calc_divider(rate, *prate, ddc->pre_div,
     68				      ddc->m_offset, NULL, NULL);
     69}
     70
     71static unsigned long sun4i_ddc_recalc_rate(struct clk_hw *hw,
     72					    unsigned long parent_rate)
     73{
     74	struct sun4i_ddc *ddc = hw_to_ddc(hw);
     75	unsigned int reg;
     76	u8 m, n;
     77
     78	regmap_field_read(ddc->reg, &reg);
     79	m = (reg >> 3) & 0xf;
     80	n = reg & 0x7;
     81
     82	return (((parent_rate / ddc->pre_div) / 10) >> n) /
     83	       (m + ddc->m_offset);
     84}
     85
     86static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
     87			      unsigned long parent_rate)
     88{
     89	struct sun4i_ddc *ddc = hw_to_ddc(hw);
     90	u8 div_m, div_n;
     91
     92	sun4i_ddc_calc_divider(rate, parent_rate, ddc->pre_div,
     93			       ddc->m_offset, &div_m, &div_n);
     94
     95	regmap_field_write(ddc->reg,
     96			   SUN4I_HDMI_DDC_CLK_M(div_m) |
     97			   SUN4I_HDMI_DDC_CLK_N(div_n));
     98
     99	return 0;
    100}
    101
    102static const struct clk_ops sun4i_ddc_ops = {
    103	.recalc_rate	= sun4i_ddc_recalc_rate,
    104	.round_rate	= sun4i_ddc_round_rate,
    105	.set_rate	= sun4i_ddc_set_rate,
    106};
    107
    108int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
    109{
    110	struct clk_init_data init;
    111	struct sun4i_ddc *ddc;
    112	const char *parent_name;
    113
    114	parent_name = __clk_get_name(parent);
    115	if (!parent_name)
    116		return -ENODEV;
    117
    118	ddc = devm_kzalloc(hdmi->dev, sizeof(*ddc), GFP_KERNEL);
    119	if (!ddc)
    120		return -ENOMEM;
    121
    122	ddc->reg = devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
    123					   hdmi->variant->ddc_clk_reg);
    124	if (IS_ERR(ddc->reg))
    125		return PTR_ERR(ddc->reg);
    126
    127	init.name = "hdmi-ddc";
    128	init.ops = &sun4i_ddc_ops;
    129	init.parent_names = &parent_name;
    130	init.num_parents = 1;
    131
    132	ddc->hdmi = hdmi;
    133	ddc->hw.init = &init;
    134	ddc->pre_div = hdmi->variant->ddc_clk_pre_divider;
    135	ddc->m_offset = hdmi->variant->ddc_clk_m_offset;
    136
    137	hdmi->ddc_clk = devm_clk_register(hdmi->dev, &ddc->hw);
    138	if (IS_ERR(hdmi->ddc_clk))
    139		return PTR_ERR(hdmi->ddc_clk);
    140
    141	return 0;
    142}