2019-08-11 21:00:29 +00:00
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* Based on drivers/clk/tegra/clk-emc.c
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* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
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*
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* Author: Dmitry Osipenko <digetx@gmail.com>
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* Copyright (C) 2019 GRATE-DRIVER project
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*/
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#define pr_fmt(fmt) "tegra-emc-clk: " fmt
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#include <linux/bits.h>
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#include <linux/clk-provider.h>
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#include <linux/clk/tegra.h>
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#include <linux/err.h>
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2020-11-04 16:48:37 +00:00
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#include <linux/export.h>
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2019-08-11 21:00:29 +00:00
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include "clk.h"
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#define CLK_SOURCE_EMC_2X_CLK_DIVISOR_MASK GENMASK(7, 0)
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#define CLK_SOURCE_EMC_2X_CLK_SRC_MASK GENMASK(31, 30)
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#define CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT 30
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#define MC_EMC_SAME_FREQ BIT(16)
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#define USE_PLLM_UD BIT(29)
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#define EMC_SRC_PLL_M 0
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#define EMC_SRC_PLL_C 1
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#define EMC_SRC_PLL_P 2
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#define EMC_SRC_CLK_M 3
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static const char * const emc_parent_clk_names[] = {
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"pll_m", "pll_c", "pll_p", "clk_m",
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};
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struct tegra_clk_emc {
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struct clk_hw hw;
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void __iomem *reg;
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bool mc_same_freq;
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bool want_low_jitter;
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tegra20_clk_emc_round_cb *round_cb;
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void *cb_arg;
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};
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static inline struct tegra_clk_emc *to_tegra_clk_emc(struct clk_hw *hw)
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{
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return container_of(hw, struct tegra_clk_emc, hw);
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}
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static unsigned long emc_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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u32 val, div;
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val = readl_relaxed(emc->reg);
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div = val & CLK_SOURCE_EMC_2X_CLK_DIVISOR_MASK;
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return DIV_ROUND_UP(parent_rate * 2, div + 2);
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}
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static u8 emc_get_parent(struct clk_hw *hw)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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return readl_relaxed(emc->reg) >> CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT;
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}
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static int emc_set_parent(struct clk_hw *hw, u8 index)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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u32 val, div;
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val = readl_relaxed(emc->reg);
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val &= ~CLK_SOURCE_EMC_2X_CLK_SRC_MASK;
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val |= index << CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT;
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div = val & CLK_SOURCE_EMC_2X_CLK_DIVISOR_MASK;
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if (index == EMC_SRC_PLL_M && div == 0 && emc->want_low_jitter)
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val |= USE_PLLM_UD;
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else
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val &= ~USE_PLLM_UD;
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if (emc->mc_same_freq)
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val |= MC_EMC_SAME_FREQ;
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else
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val &= ~MC_EMC_SAME_FREQ;
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writel_relaxed(val, emc->reg);
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fence_udelay(1, emc->reg);
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return 0;
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}
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static int emc_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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unsigned int index;
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u32 val, div;
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div = div_frac_get(rate, parent_rate, 8, 1, 0);
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val = readl_relaxed(emc->reg);
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val &= ~CLK_SOURCE_EMC_2X_CLK_DIVISOR_MASK;
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val |= div;
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index = val >> CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT;
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if (index == EMC_SRC_PLL_M && div == 0 && emc->want_low_jitter)
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val |= USE_PLLM_UD;
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else
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val &= ~USE_PLLM_UD;
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if (emc->mc_same_freq)
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val |= MC_EMC_SAME_FREQ;
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else
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val &= ~MC_EMC_SAME_FREQ;
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writel_relaxed(val, emc->reg);
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fence_udelay(1, emc->reg);
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return 0;
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}
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static int emc_set_rate_and_parent(struct clk_hw *hw,
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unsigned long rate,
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unsigned long parent_rate,
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u8 index)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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u32 val, div;
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div = div_frac_get(rate, parent_rate, 8, 1, 0);
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val = readl_relaxed(emc->reg);
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val &= ~CLK_SOURCE_EMC_2X_CLK_SRC_MASK;
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val |= index << CLK_SOURCE_EMC_2X_CLK_SRC_SHIFT;
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val &= ~CLK_SOURCE_EMC_2X_CLK_DIVISOR_MASK;
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val |= div;
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if (index == EMC_SRC_PLL_M && div == 0 && emc->want_low_jitter)
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val |= USE_PLLM_UD;
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else
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val &= ~USE_PLLM_UD;
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if (emc->mc_same_freq)
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val |= MC_EMC_SAME_FREQ;
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else
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val &= ~MC_EMC_SAME_FREQ;
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writel_relaxed(val, emc->reg);
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fence_udelay(1, emc->reg);
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return 0;
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}
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static int emc_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
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{
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struct tegra_clk_emc *emc = to_tegra_clk_emc(hw);
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struct clk_hw *parent_hw;
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unsigned long divided_rate;
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unsigned long parent_rate;
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unsigned int i;
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long emc_rate;
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int div;
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emc_rate = emc->round_cb(req->rate, req->min_rate, req->max_rate,
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emc->cb_arg);
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if (emc_rate < 0)
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return emc_rate;
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for (i = 0; i < ARRAY_SIZE(emc_parent_clk_names); i++) {
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parent_hw = clk_hw_get_parent_by_index(hw, i);
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if (req->best_parent_hw == parent_hw)
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parent_rate = req->best_parent_rate;
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else
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parent_rate = clk_hw_get_rate(parent_hw);
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if (emc_rate > parent_rate)
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continue;
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div = div_frac_get(emc_rate, parent_rate, 8, 1, 0);
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divided_rate = DIV_ROUND_UP(parent_rate * 2, div + 2);
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if (divided_rate != emc_rate)
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continue;
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req->best_parent_rate = parent_rate;
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req->best_parent_hw = parent_hw;
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req->rate = emc_rate;
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break;
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}
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if (i == ARRAY_SIZE(emc_parent_clk_names)) {
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pr_err_once("can't find parent for rate %lu emc_rate %lu\n",
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req->rate, emc_rate);
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return -EINVAL;
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}
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return 0;
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}
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static const struct clk_ops tegra_clk_emc_ops = {
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.recalc_rate = emc_recalc_rate,
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.get_parent = emc_get_parent,
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.set_parent = emc_set_parent,
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.set_rate = emc_set_rate,
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.set_rate_and_parent = emc_set_rate_and_parent,
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.determine_rate = emc_determine_rate,
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};
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void tegra20_clk_set_emc_round_callback(tegra20_clk_emc_round_cb *round_cb,
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void *cb_arg)
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{
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struct clk *clk = __clk_lookup("emc");
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struct tegra_clk_emc *emc;
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struct clk_hw *hw;
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if (clk) {
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hw = __clk_get_hw(clk);
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emc = to_tegra_clk_emc(hw);
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emc->round_cb = round_cb;
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emc->cb_arg = cb_arg;
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}
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}
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2020-11-04 16:48:37 +00:00
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EXPORT_SYMBOL_GPL(tegra20_clk_set_emc_round_callback);
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2019-08-11 21:00:29 +00:00
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bool tegra20_clk_emc_driver_available(struct clk_hw *emc_hw)
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{
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return to_tegra_clk_emc(emc_hw)->round_cb != NULL;
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}
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struct clk *tegra20_clk_register_emc(void __iomem *ioaddr, bool low_jitter)
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{
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struct tegra_clk_emc *emc;
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struct clk_init_data init;
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struct clk *clk;
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emc = kzalloc(sizeof(*emc), GFP_KERNEL);
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if (!emc)
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return NULL;
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/*
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* EMC stands for External Memory Controller.
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*
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* We don't want EMC clock to be disabled ever by gating its
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* parent and whatnot because system is busted immediately in that
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* case, hence the clock is marked as critical.
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*/
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init.name = "emc";
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init.ops = &tegra_clk_emc_ops;
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init.flags = CLK_IS_CRITICAL;
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init.parent_names = emc_parent_clk_names;
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init.num_parents = ARRAY_SIZE(emc_parent_clk_names);
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emc->reg = ioaddr;
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emc->hw.init = &init;
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emc->want_low_jitter = low_jitter;
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clk = clk_register(NULL, &emc->hw);
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if (IS_ERR(clk)) {
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kfree(emc);
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return NULL;
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}
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return clk;
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}
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int tegra20_clk_prepare_emc_mc_same_freq(struct clk *emc_clk, bool same)
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{
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struct tegra_clk_emc *emc;
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struct clk_hw *hw;
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if (!emc_clk)
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return -EINVAL;
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hw = __clk_get_hw(emc_clk);
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emc = to_tegra_clk_emc(hw);
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emc->mc_same_freq = same;
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return 0;
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}
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2020-11-04 16:48:37 +00:00
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EXPORT_SYMBOL_GPL(tegra20_clk_prepare_emc_mc_same_freq);
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