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| 1 | +// SPDX-License-Identifier: GPL-2.0-only |
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| 1 | 2 | /* |
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| 2 | 3 | * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. |
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| 3 | | - * |
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| 4 | | - * This program is free software; you can redistribute it and/or modify it |
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| 5 | | - * under the terms and conditions of the GNU General Public License, |
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| 6 | | - * version 2, as published by the Free Software Foundation. |
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| 7 | | - * |
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| 8 | | - * This program is distributed in the hope it will be useful, but WITHOUT |
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| 9 | | - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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| 10 | | - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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| 11 | | - * more details. |
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| 12 | | - * |
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| 13 | | - * You should have received a copy of the GNU General Public License |
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| 14 | | - * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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| 15 | 4 | */ |
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| 16 | 5 | |
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| 17 | 6 | #include <linux/clk-provider.h> |
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| .. | .. |
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| 59 | 48 | return state; |
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| 60 | 49 | } |
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| 61 | 50 | |
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| 62 | | -static int clk_periph_enable(struct clk_hw *hw) |
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| 51 | +static void clk_periph_enable_locked(struct clk_hw *hw) |
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| 63 | 52 | { |
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| 64 | 53 | struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); |
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| 65 | | - unsigned long flags = 0; |
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| 66 | | - |
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| 67 | | - spin_lock_irqsave(&periph_ref_lock, flags); |
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| 68 | | - |
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| 69 | | - gate->enable_refcnt[gate->clk_num]++; |
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| 70 | | - if (gate->enable_refcnt[gate->clk_num] > 1) { |
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| 71 | | - spin_unlock_irqrestore(&periph_ref_lock, flags); |
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| 72 | | - return 0; |
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| 73 | | - } |
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| 74 | 54 | |
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| 75 | 55 | write_enb_set(periph_clk_to_bit(gate), gate); |
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| 76 | 56 | udelay(2); |
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| .. | .. |
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| 89 | 69 | udelay(1); |
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| 90 | 70 | writel_relaxed(0, gate->clk_base + LVL2_CLK_GATE_OVRE); |
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| 91 | 71 | } |
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| 72 | +} |
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| 73 | + |
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| 74 | +static void clk_periph_disable_locked(struct clk_hw *hw) |
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| 75 | +{ |
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| 76 | + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); |
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| 77 | + |
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| 78 | + /* |
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| 79 | + * If peripheral is in the APB bus then read the APB bus to |
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| 80 | + * flush the write operation in apb bus. This will avoid the |
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| 81 | + * peripheral access after disabling clock |
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| 82 | + */ |
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| 83 | + if (gate->flags & TEGRA_PERIPH_ON_APB) |
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| 84 | + tegra_read_chipid(); |
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| 85 | + |
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| 86 | + write_enb_clr(periph_clk_to_bit(gate), gate); |
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| 87 | +} |
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| 88 | + |
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| 89 | +static int clk_periph_enable(struct clk_hw *hw) |
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| 90 | +{ |
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| 91 | + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); |
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| 92 | + unsigned long flags = 0; |
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| 93 | + |
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| 94 | + spin_lock_irqsave(&periph_ref_lock, flags); |
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| 95 | + |
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| 96 | + if (!gate->enable_refcnt[gate->clk_num]++) |
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| 97 | + clk_periph_enable_locked(hw); |
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| 92 | 98 | |
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| 93 | 99 | spin_unlock_irqrestore(&periph_ref_lock, flags); |
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| 94 | 100 | |
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| .. | .. |
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| 102 | 108 | |
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| 103 | 109 | spin_lock_irqsave(&periph_ref_lock, flags); |
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| 104 | 110 | |
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| 105 | | - gate->enable_refcnt[gate->clk_num]--; |
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| 106 | | - if (gate->enable_refcnt[gate->clk_num] > 0) { |
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| 107 | | - spin_unlock_irqrestore(&periph_ref_lock, flags); |
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| 108 | | - return; |
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| 109 | | - } |
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| 111 | + WARN_ON(!gate->enable_refcnt[gate->clk_num]); |
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| 112 | + |
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| 113 | + if (--gate->enable_refcnt[gate->clk_num] == 0) |
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| 114 | + clk_periph_disable_locked(hw); |
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| 115 | + |
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| 116 | + spin_unlock_irqrestore(&periph_ref_lock, flags); |
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| 117 | +} |
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| 118 | + |
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| 119 | +static void clk_periph_disable_unused(struct clk_hw *hw) |
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| 120 | +{ |
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| 121 | + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); |
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| 122 | + unsigned long flags = 0; |
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| 123 | + |
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| 124 | + spin_lock_irqsave(&periph_ref_lock, flags); |
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| 110 | 125 | |
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| 111 | 126 | /* |
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| 112 | | - * If peripheral is in the APB bus then read the APB bus to |
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| 113 | | - * flush the write operation in apb bus. This will avoid the |
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| 114 | | - * peripheral access after disabling clock |
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| 127 | + * Some clocks are duplicated and some of them are marked as critical, |
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| 128 | + * like fuse and fuse_burn for example, thus the enable_refcnt will |
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| 129 | + * be non-zero here if the "unused" duplicate is disabled by CCF. |
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| 115 | 130 | */ |
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| 116 | | - if (gate->flags & TEGRA_PERIPH_ON_APB) |
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| 117 | | - tegra_read_chipid(); |
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| 118 | | - |
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| 119 | | - write_enb_clr(periph_clk_to_bit(gate), gate); |
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| 131 | + if (!gate->enable_refcnt[gate->clk_num]) |
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| 132 | + clk_periph_disable_locked(hw); |
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| 120 | 133 | |
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| 121 | 134 | spin_unlock_irqrestore(&periph_ref_lock, flags); |
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| 122 | 135 | } |
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| .. | .. |
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| 125 | 138 | .is_enabled = clk_periph_is_enabled, |
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| 126 | 139 | .enable = clk_periph_enable, |
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| 127 | 140 | .disable = clk_periph_disable, |
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| 141 | + .disable_unused = clk_periph_disable_unused, |
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| 128 | 142 | }; |
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| 129 | 143 | |
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| 130 | 144 | struct clk *tegra_clk_register_periph_gate(const char *name, |
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| .. | .. |
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| 133 | 147 | { |
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| 134 | 148 | struct tegra_clk_periph_gate *gate; |
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| 135 | 149 | struct clk *clk; |
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| 136 | | - struct clk_init_data init = {}; |
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| 150 | + struct clk_init_data init; |
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| 137 | 151 | const struct tegra_clk_periph_regs *pregs; |
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| 138 | 152 | |
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| 139 | 153 | pregs = get_reg_bank(clk_num); |
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| .. | .. |
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| 158 | 172 | gate->flags = gate_flags; |
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| 159 | 173 | gate->enable_refcnt = enable_refcnt; |
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| 160 | 174 | gate->regs = pregs; |
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| 161 | | - |
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| 162 | | - if (read_enb(gate) & periph_clk_to_bit(gate)) |
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| 163 | | - enable_refcnt[clk_num]++; |
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| 164 | 175 | |
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| 165 | 176 | /* Data in .init is copied by clk_register(), so stack variable OK */ |
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| 166 | 177 | gate->hw.init = &init; |
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