mirror of https://gitee.com/openkylin/linux.git
541 lines
13 KiB
C
541 lines
13 KiB
C
/*
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* drivers/clk/tegra/clk-emc.c
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*
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* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
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*
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* Author:
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* Mikko Perttunen <mperttunen@nvidia.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/clk-provider.h>
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#include <linux/clk.h>
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#include <linux/clkdev.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/sort.h>
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#include <linux/string.h>
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#include <soc/tegra/fuse.h>
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#include <soc/tegra/emc.h>
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#include "clk.h"
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#define CLK_SOURCE_EMC 0x19c
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#define CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR_SHIFT 0
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#define CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR_MASK 0xff
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#define CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR(x) (((x) & CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR_MASK) << \
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CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR_SHIFT)
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#define CLK_SOURCE_EMC_EMC_2X_CLK_SRC_SHIFT 29
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#define CLK_SOURCE_EMC_EMC_2X_CLK_SRC_MASK 0x7
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#define CLK_SOURCE_EMC_EMC_2X_CLK_SRC(x) (((x) & CLK_SOURCE_EMC_EMC_2X_CLK_SRC_MASK) << \
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CLK_SOURCE_EMC_EMC_2X_CLK_SRC_SHIFT)
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static const char * const emc_parent_clk_names[] = {
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"pll_m", "pll_c", "pll_p", "clk_m", "pll_m_ud",
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"pll_c2", "pll_c3", "pll_c_ud"
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};
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/*
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* List of clock sources for various parents the EMC clock can have.
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* When we change the timing to a timing with a parent that has the same
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* clock source as the current parent, we must first change to a backup
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* timing that has a different clock source.
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*/
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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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#define EMC_SRC_PLL_C2 4
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#define EMC_SRC_PLL_C3 5
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static const char emc_parent_clk_sources[] = {
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EMC_SRC_PLL_M, EMC_SRC_PLL_C, EMC_SRC_PLL_P, EMC_SRC_CLK_M,
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EMC_SRC_PLL_M, EMC_SRC_PLL_C2, EMC_SRC_PLL_C3, EMC_SRC_PLL_C
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};
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struct emc_timing {
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unsigned long rate, parent_rate;
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u8 parent_index;
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struct clk *parent;
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u32 ram_code;
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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 *clk_regs;
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struct clk *prev_parent;
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bool changing_timing;
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struct device_node *emc_node;
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struct tegra_emc *emc;
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int num_timings;
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struct emc_timing *timings;
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spinlock_t *lock;
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};
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/* Common clock framework callback implementations */
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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 *tegra;
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u32 val, div;
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tegra = container_of(hw, struct tegra_clk_emc, hw);
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/*
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* CCF wrongly assumes that the parent won't change during set_rate,
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* so get the parent rate explicitly.
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*/
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parent_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
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val = readl(tegra->clk_regs + CLK_SOURCE_EMC);
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div = val & CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR_MASK;
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return parent_rate / (div + 2) * 2;
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}
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/*
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* Rounds up unless no higher rate exists, in which case down. This way is
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* safer since things have EMC rate floors. Also don't touch parent_rate
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* since we don't want the CCF to play with our parent clocks.
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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 *tegra;
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u8 ram_code = tegra_read_ram_code();
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struct emc_timing *timing = NULL;
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int i;
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tegra = container_of(hw, struct tegra_clk_emc, hw);
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for (i = 0; i < tegra->num_timings; i++) {
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if (tegra->timings[i].ram_code != ram_code)
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continue;
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timing = tegra->timings + i;
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if (timing->rate > req->max_rate) {
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i = min(i, 1);
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req->rate = tegra->timings[i - 1].rate;
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return 0;
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}
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if (timing->rate < req->min_rate)
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continue;
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if (timing->rate >= req->rate) {
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req->rate = timing->rate;
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return 0;
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}
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}
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if (timing) {
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req->rate = timing->rate;
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return 0;
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}
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req->rate = clk_hw_get_rate(hw);
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return 0;
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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 *tegra;
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u32 val;
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tegra = container_of(hw, struct tegra_clk_emc, hw);
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val = readl(tegra->clk_regs + CLK_SOURCE_EMC);
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return (val >> CLK_SOURCE_EMC_EMC_2X_CLK_SRC_SHIFT)
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& CLK_SOURCE_EMC_EMC_2X_CLK_SRC_MASK;
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}
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static struct tegra_emc *emc_ensure_emc_driver(struct tegra_clk_emc *tegra)
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{
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struct platform_device *pdev;
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if (tegra->emc)
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return tegra->emc;
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if (!tegra->emc_node)
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return NULL;
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pdev = of_find_device_by_node(tegra->emc_node);
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if (!pdev) {
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pr_err("%s: could not get external memory controller\n",
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__func__);
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return NULL;
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}
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of_node_put(tegra->emc_node);
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tegra->emc_node = NULL;
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tegra->emc = platform_get_drvdata(pdev);
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if (!tegra->emc) {
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pr_err("%s: cannot find EMC driver\n", __func__);
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return NULL;
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}
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return tegra->emc;
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}
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static int emc_set_timing(struct tegra_clk_emc *tegra,
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struct emc_timing *timing)
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{
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int err;
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u8 div;
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u32 car_value;
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unsigned long flags = 0;
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struct tegra_emc *emc = emc_ensure_emc_driver(tegra);
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if (!emc)
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return -ENOENT;
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pr_debug("going to rate %ld prate %ld p %s\n", timing->rate,
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timing->parent_rate, __clk_get_name(timing->parent));
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if (emc_get_parent(&tegra->hw) == timing->parent_index &&
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clk_get_rate(timing->parent) != timing->parent_rate) {
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BUG();
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return -EINVAL;
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}
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tegra->changing_timing = true;
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err = clk_set_rate(timing->parent, timing->parent_rate);
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if (err) {
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pr_err("cannot change parent %s rate to %ld: %d\n",
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__clk_get_name(timing->parent), timing->parent_rate,
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err);
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return err;
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}
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err = clk_prepare_enable(timing->parent);
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if (err) {
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pr_err("cannot enable parent clock: %d\n", err);
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return err;
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}
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div = timing->parent_rate / (timing->rate / 2) - 2;
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err = tegra_emc_prepare_timing_change(emc, timing->rate);
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if (err)
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return err;
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spin_lock_irqsave(tegra->lock, flags);
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car_value = readl(tegra->clk_regs + CLK_SOURCE_EMC);
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car_value &= ~CLK_SOURCE_EMC_EMC_2X_CLK_SRC(~0);
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car_value |= CLK_SOURCE_EMC_EMC_2X_CLK_SRC(timing->parent_index);
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car_value &= ~CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR(~0);
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car_value |= CLK_SOURCE_EMC_EMC_2X_CLK_DIVISOR(div);
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writel(car_value, tegra->clk_regs + CLK_SOURCE_EMC);
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spin_unlock_irqrestore(tegra->lock, flags);
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tegra_emc_complete_timing_change(emc, timing->rate);
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clk_hw_reparent(&tegra->hw, __clk_get_hw(timing->parent));
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clk_disable_unprepare(tegra->prev_parent);
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tegra->prev_parent = timing->parent;
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tegra->changing_timing = false;
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return 0;
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}
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/*
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* Get backup timing to use as an intermediate step when a change between
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* two timings with the same clock source has been requested. First try to
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* find a timing with a higher clock rate to avoid a rate below any set rate
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* floors. If that is not possible, find a lower rate.
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*/
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static struct emc_timing *get_backup_timing(struct tegra_clk_emc *tegra,
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int timing_index)
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{
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int i;
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u32 ram_code = tegra_read_ram_code();
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struct emc_timing *timing;
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for (i = timing_index+1; i < tegra->num_timings; i++) {
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timing = tegra->timings + i;
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if (timing->ram_code != ram_code)
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continue;
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if (emc_parent_clk_sources[timing->parent_index] !=
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emc_parent_clk_sources[
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tegra->timings[timing_index].parent_index])
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return timing;
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}
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for (i = timing_index-1; i >= 0; --i) {
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timing = tegra->timings + i;
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if (timing->ram_code != ram_code)
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continue;
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if (emc_parent_clk_sources[timing->parent_index] !=
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emc_parent_clk_sources[
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tegra->timings[timing_index].parent_index])
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return timing;
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}
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return NULL;
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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 *tegra;
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struct emc_timing *timing = NULL;
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int i, err;
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u32 ram_code = tegra_read_ram_code();
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tegra = container_of(hw, struct tegra_clk_emc, hw);
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if (clk_hw_get_rate(hw) == rate)
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return 0;
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/*
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* When emc_set_timing changes the parent rate, CCF will propagate
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* that downward to us, so ignore any set_rate calls while a rate
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* change is already going on.
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*/
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if (tegra->changing_timing)
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return 0;
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for (i = 0; i < tegra->num_timings; i++) {
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if (tegra->timings[i].rate == rate &&
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tegra->timings[i].ram_code == ram_code) {
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timing = tegra->timings + i;
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break;
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}
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}
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if (!timing) {
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pr_err("cannot switch to rate %ld without emc table\n", rate);
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return -EINVAL;
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}
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if (emc_parent_clk_sources[emc_get_parent(hw)] ==
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emc_parent_clk_sources[timing->parent_index] &&
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clk_get_rate(timing->parent) != timing->parent_rate) {
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/*
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* Parent clock source not changed but parent rate has changed,
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* need to temporarily switch to another parent
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*/
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struct emc_timing *backup_timing;
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backup_timing = get_backup_timing(tegra, i);
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if (!backup_timing) {
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pr_err("cannot find backup timing\n");
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return -EINVAL;
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}
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pr_debug("using %ld as backup rate when going to %ld\n",
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backup_timing->rate, rate);
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err = emc_set_timing(tegra, backup_timing);
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if (err) {
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pr_err("cannot set backup timing: %d\n", err);
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return err;
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}
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}
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return emc_set_timing(tegra, timing);
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}
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/* Initialization and deinitialization */
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static int load_one_timing_from_dt(struct tegra_clk_emc *tegra,
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struct emc_timing *timing,
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struct device_node *node)
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{
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int err, i;
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u32 tmp;
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err = of_property_read_u32(node, "clock-frequency", &tmp);
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if (err) {
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pr_err("timing %s: failed to read rate\n", node->full_name);
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return err;
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}
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timing->rate = tmp;
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err = of_property_read_u32(node, "nvidia,parent-clock-frequency", &tmp);
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if (err) {
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pr_err("timing %s: failed to read parent rate\n",
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node->full_name);
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return err;
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}
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timing->parent_rate = tmp;
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timing->parent = of_clk_get_by_name(node, "emc-parent");
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if (IS_ERR(timing->parent)) {
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pr_err("timing %s: failed to get parent clock\n",
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node->full_name);
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return PTR_ERR(timing->parent);
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}
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timing->parent_index = 0xff;
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for (i = 0; i < ARRAY_SIZE(emc_parent_clk_names); i++) {
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if (!strcmp(emc_parent_clk_names[i],
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__clk_get_name(timing->parent))) {
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timing->parent_index = i;
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break;
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}
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}
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if (timing->parent_index == 0xff) {
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pr_err("timing %s: %s is not a valid parent\n",
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node->full_name, __clk_get_name(timing->parent));
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clk_put(timing->parent);
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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 int cmp_timings(const void *_a, const void *_b)
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{
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const struct emc_timing *a = _a;
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const struct emc_timing *b = _b;
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if (a->rate < b->rate)
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return -1;
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else if (a->rate == b->rate)
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return 0;
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else
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return 1;
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}
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static int load_timings_from_dt(struct tegra_clk_emc *tegra,
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struct device_node *node,
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u32 ram_code)
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{
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struct device_node *child;
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int child_count = of_get_child_count(node);
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int i = 0, err;
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tegra->timings = kcalloc(child_count, sizeof(struct emc_timing),
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GFP_KERNEL);
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if (!tegra->timings)
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return -ENOMEM;
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tegra->num_timings = child_count;
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for_each_child_of_node(node, child) {
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struct emc_timing *timing = tegra->timings + (i++);
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err = load_one_timing_from_dt(tegra, timing, child);
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if (err)
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return err;
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timing->ram_code = ram_code;
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}
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sort(tegra->timings, tegra->num_timings, sizeof(struct emc_timing),
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cmp_timings, NULL);
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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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.determine_rate = emc_determine_rate,
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.set_rate = emc_set_rate,
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.get_parent = emc_get_parent,
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};
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struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
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spinlock_t *lock)
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{
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struct tegra_clk_emc *tegra;
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struct clk_init_data init;
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struct device_node *node;
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u32 node_ram_code;
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struct clk *clk;
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int err;
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tegra = kcalloc(1, sizeof(*tegra), GFP_KERNEL);
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if (!tegra)
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return ERR_PTR(-ENOMEM);
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tegra->clk_regs = base;
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tegra->lock = lock;
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tegra->num_timings = 0;
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for_each_child_of_node(np, node) {
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err = of_property_read_u32(node, "nvidia,ram-code",
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&node_ram_code);
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if (err) {
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of_node_put(node);
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continue;
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}
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/*
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* Store timings for all ram codes as we cannot read the
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* fuses until the apbmisc driver is loaded.
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*/
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err = load_timings_from_dt(tegra, node, node_ram_code);
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if (err)
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return ERR_PTR(err);
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of_node_put(node);
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break;
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}
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if (tegra->num_timings == 0)
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pr_warn("%s: no memory timings registered\n", __func__);
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tegra->emc_node = of_parse_phandle(np,
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"nvidia,external-memory-controller", 0);
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if (!tegra->emc_node)
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pr_warn("%s: couldn't find node for EMC driver\n", __func__);
|
|
|
|
init.name = "emc";
|
|
init.ops = &tegra_clk_emc_ops;
|
|
init.flags = 0;
|
|
init.parent_names = emc_parent_clk_names;
|
|
init.num_parents = ARRAY_SIZE(emc_parent_clk_names);
|
|
|
|
tegra->hw.init = &init;
|
|
|
|
clk = clk_register(NULL, &tegra->hw);
|
|
if (IS_ERR(clk))
|
|
return clk;
|
|
|
|
tegra->prev_parent = clk_hw_get_parent_by_index(
|
|
&tegra->hw, emc_get_parent(&tegra->hw))->clk;
|
|
tegra->changing_timing = false;
|
|
|
|
/* Allow debugging tools to see the EMC clock */
|
|
clk_register_clkdev(clk, "emc", "tegra-clk-debug");
|
|
|
|
clk_prepare_enable(clk);
|
|
|
|
return clk;
|
|
};
|