|
| 1 | +// SPDX-License-Identifier: GPL-2.0-only |
| 2 | +/* |
| 3 | + * Based on clk-super.c |
| 4 | + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. |
| 5 | + * |
| 6 | + * Based on older tegra20-cpufreq driver by Colin Cross <[email protected]> |
| 7 | + * Copyright (C) 2010 Google, Inc. |
| 8 | + * |
| 9 | + * Author: Dmitry Osipenko <[email protected]> |
| 10 | + * Copyright (C) 2019 GRATE-DRIVER project |
| 11 | + */ |
| 12 | + |
| 13 | +#include <linux/bits.h> |
| 14 | +#include <linux/clk-provider.h> |
| 15 | +#include <linux/err.h> |
| 16 | +#include <linux/io.h> |
| 17 | +#include <linux/kernel.h> |
| 18 | +#include <linux/slab.h> |
| 19 | +#include <linux/types.h> |
| 20 | + |
| 21 | +#include "clk.h" |
| 22 | + |
| 23 | +#define PLLP_INDEX 4 |
| 24 | +#define PLLX_INDEX 8 |
| 25 | + |
| 26 | +#define SUPER_CDIV_ENB BIT(31) |
| 27 | + |
| 28 | +static struct tegra_clk_super_mux *cclk_super; |
| 29 | +static bool cclk_on_pllx; |
| 30 | + |
| 31 | +static u8 cclk_super_get_parent(struct clk_hw *hw) |
| 32 | +{ |
| 33 | + return tegra_clk_super_ops.get_parent(hw); |
| 34 | +} |
| 35 | + |
| 36 | +static int cclk_super_set_parent(struct clk_hw *hw, u8 index) |
| 37 | +{ |
| 38 | + return tegra_clk_super_ops.set_parent(hw, index); |
| 39 | +} |
| 40 | + |
| 41 | +static int cclk_super_set_rate(struct clk_hw *hw, unsigned long rate, |
| 42 | + unsigned long parent_rate) |
| 43 | +{ |
| 44 | + return tegra_clk_super_ops.set_rate(hw, rate, parent_rate); |
| 45 | +} |
| 46 | + |
| 47 | +static unsigned long cclk_super_recalc_rate(struct clk_hw *hw, |
| 48 | + unsigned long parent_rate) |
| 49 | +{ |
| 50 | + if (cclk_super_get_parent(hw) == PLLX_INDEX) |
| 51 | + return parent_rate; |
| 52 | + |
| 53 | + return tegra_clk_super_ops.recalc_rate(hw, parent_rate); |
| 54 | +} |
| 55 | + |
| 56 | +static int cclk_super_determine_rate(struct clk_hw *hw, |
| 57 | + struct clk_rate_request *req) |
| 58 | +{ |
| 59 | + struct clk_hw *pllp_hw = clk_hw_get_parent_by_index(hw, PLLP_INDEX); |
| 60 | + struct clk_hw *pllx_hw = clk_hw_get_parent_by_index(hw, PLLX_INDEX); |
| 61 | + struct tegra_clk_super_mux *super = to_clk_super_mux(hw); |
| 62 | + unsigned long pllp_rate; |
| 63 | + long rate = req->rate; |
| 64 | + |
| 65 | + if (WARN_ON_ONCE(!pllp_hw || !pllx_hw)) |
| 66 | + return -EINVAL; |
| 67 | + |
| 68 | + /* |
| 69 | + * Switch parent to PLLP for all CCLK rates that are suitable for PLLP. |
| 70 | + * PLLX will be disabled in this case, saving some power. |
| 71 | + */ |
| 72 | + pllp_rate = clk_hw_get_rate(pllp_hw); |
| 73 | + |
| 74 | + if (rate <= pllp_rate) { |
| 75 | + if (super->flags & TEGRA20_SUPER_CLK) |
| 76 | + rate = pllp_rate; |
| 77 | + else |
| 78 | + rate = tegra_clk_super_ops.round_rate(hw, rate, |
| 79 | + &pllp_rate); |
| 80 | + |
| 81 | + req->best_parent_rate = pllp_rate; |
| 82 | + req->best_parent_hw = pllp_hw; |
| 83 | + req->rate = rate; |
| 84 | + } else { |
| 85 | + rate = clk_hw_round_rate(pllx_hw, rate); |
| 86 | + req->best_parent_rate = rate; |
| 87 | + req->best_parent_hw = pllx_hw; |
| 88 | + req->rate = rate; |
| 89 | + } |
| 90 | + |
| 91 | + if (WARN_ON_ONCE(rate <= 0)) |
| 92 | + return -EINVAL; |
| 93 | + |
| 94 | + return 0; |
| 95 | +} |
| 96 | + |
| 97 | +static const struct clk_ops tegra_cclk_super_ops = { |
| 98 | + .get_parent = cclk_super_get_parent, |
| 99 | + .set_parent = cclk_super_set_parent, |
| 100 | + .set_rate = cclk_super_set_rate, |
| 101 | + .recalc_rate = cclk_super_recalc_rate, |
| 102 | + .determine_rate = cclk_super_determine_rate, |
| 103 | +}; |
| 104 | + |
| 105 | +static const struct clk_ops tegra_cclk_super_mux_ops = { |
| 106 | + .get_parent = cclk_super_get_parent, |
| 107 | + .set_parent = cclk_super_set_parent, |
| 108 | + .determine_rate = cclk_super_determine_rate, |
| 109 | +}; |
| 110 | + |
| 111 | +struct clk *tegra_clk_register_super_cclk(const char *name, |
| 112 | + const char * const *parent_names, u8 num_parents, |
| 113 | + unsigned long flags, void __iomem *reg, u8 clk_super_flags, |
| 114 | + spinlock_t *lock) |
| 115 | +{ |
| 116 | + struct tegra_clk_super_mux *super; |
| 117 | + struct clk *clk; |
| 118 | + struct clk_init_data init; |
| 119 | + u32 val; |
| 120 | + |
| 121 | + if (WARN_ON(cclk_super)) |
| 122 | + return ERR_PTR(-EBUSY); |
| 123 | + |
| 124 | + super = kzalloc(sizeof(*super), GFP_KERNEL); |
| 125 | + if (!super) |
| 126 | + return ERR_PTR(-ENOMEM); |
| 127 | + |
| 128 | + init.name = name; |
| 129 | + init.flags = flags; |
| 130 | + init.parent_names = parent_names; |
| 131 | + init.num_parents = num_parents; |
| 132 | + |
| 133 | + super->reg = reg; |
| 134 | + super->lock = lock; |
| 135 | + super->width = 4; |
| 136 | + super->flags = clk_super_flags; |
| 137 | + super->hw.init = &init; |
| 138 | + |
| 139 | + if (super->flags & TEGRA20_SUPER_CLK) { |
| 140 | + init.ops = &tegra_cclk_super_mux_ops; |
| 141 | + } else { |
| 142 | + init.ops = &tegra_cclk_super_ops; |
| 143 | + |
| 144 | + super->frac_div.reg = reg + 4; |
| 145 | + super->frac_div.shift = 16; |
| 146 | + super->frac_div.width = 8; |
| 147 | + super->frac_div.frac_width = 1; |
| 148 | + super->frac_div.lock = lock; |
| 149 | + super->div_ops = &tegra_clk_frac_div_ops; |
| 150 | + } |
| 151 | + |
| 152 | + /* |
| 153 | + * Tegra30+ has the following CPUG clock topology: |
| 154 | + * |
| 155 | + * +---+ +-------+ +-+ +-+ +-+ |
| 156 | + * PLLP+->+ +->+DIVIDER+->+0| +-------->+0| ------------->+0| |
| 157 | + * | | +-------+ | | | +---+ | | | | | |
| 158 | + * PLLC+->+MUX| | +->+ | S | | +->+ | +->+CPU |
| 159 | + * ... | | | | | | K | | | | +-------+ | | |
| 160 | + * PLLX+->+-->+------------>+1| +->+ I +->+1| +->+ DIV2 +->+1| |
| 161 | + * +---+ +++ | P | +++ |SKIPPER| +++ |
| 162 | + * ^ | P | ^ +-------+ ^ |
| 163 | + * | | E | | | |
| 164 | + * PLLX_SEL+--+ | R | | OVERHEAT+--+ |
| 165 | + * +---+ | |
| 166 | + * | |
| 167 | + * SUPER_CDIV_ENB+--+ |
| 168 | + * |
| 169 | + * Tegra20 is similar, but simpler. It doesn't have the divider and |
| 170 | + * thermal DIV2 skipper. |
| 171 | + * |
| 172 | + * At least for now we're not going to use clock-skipper, hence let's |
| 173 | + * ensure that it is disabled. |
| 174 | + */ |
| 175 | + val = readl_relaxed(reg + 4); |
| 176 | + val &= ~SUPER_CDIV_ENB; |
| 177 | + writel_relaxed(val, reg + 4); |
| 178 | + |
| 179 | + clk = clk_register(NULL, &super->hw); |
| 180 | + if (IS_ERR(clk)) |
| 181 | + kfree(super); |
| 182 | + else |
| 183 | + cclk_super = super; |
| 184 | + |
| 185 | + return clk; |
| 186 | +} |
| 187 | + |
| 188 | +int tegra_cclk_pre_pllx_rate_change(void) |
| 189 | +{ |
| 190 | + if (IS_ERR_OR_NULL(cclk_super)) |
| 191 | + return -EINVAL; |
| 192 | + |
| 193 | + if (cclk_super_get_parent(&cclk_super->hw) == PLLX_INDEX) |
| 194 | + cclk_on_pllx = true; |
| 195 | + else |
| 196 | + cclk_on_pllx = false; |
| 197 | + |
| 198 | + /* |
| 199 | + * CPU needs to be temporarily re-parented away from PLLX if PLLX |
| 200 | + * changes its rate. PLLP is a safe parent for CPU on all Tegra SoCs. |
| 201 | + */ |
| 202 | + if (cclk_on_pllx) |
| 203 | + cclk_super_set_parent(&cclk_super->hw, PLLP_INDEX); |
| 204 | + |
| 205 | + return 0; |
| 206 | +} |
| 207 | + |
| 208 | +void tegra_cclk_post_pllx_rate_change(void) |
| 209 | +{ |
| 210 | + if (cclk_on_pllx) |
| 211 | + cclk_super_set_parent(&cclk_super->hw, PLLX_INDEX); |
| 212 | +} |
0 commit comments