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68b3b6f177
Mark DDR clocks as critical for AT91 devices. These clocks are enabled by bootloader when initializing DDR and needs to stay enabled. Up to this patch the DDR clocks were requested from drivers/memory/atmel-sdramc.c which does only clock request and enable. There is no need to have a separate driver just for this, thus the atmel-sdramc.c will be deleted in a subsequent patch. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Link: https://lore.kernel.org/r/20221208114515.35179-2-claudiu.beznea@microchip.com
141 lines
2.8 KiB
C
141 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
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*/
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <linux/clk/at91_pmc.h>
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#include <linux/of.h>
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#include <linux/mfd/syscon.h>
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#include <linux/regmap.h>
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#include "pmc.h"
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#define SYSTEM_MAX_ID 31
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#define SYSTEM_MAX_NAME_SZ 32
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#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
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struct clk_system {
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struct clk_hw hw;
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struct regmap *regmap;
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struct at91_clk_pms pms;
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u8 id;
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};
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static inline int is_pck(int id)
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{
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return (id >= 8) && (id <= 15);
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}
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static inline bool clk_system_ready(struct regmap *regmap, int id)
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{
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unsigned int status;
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regmap_read(regmap, AT91_PMC_SR, &status);
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return !!(status & (1 << id));
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}
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static int clk_system_prepare(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
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if (!is_pck(sys->id))
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return 0;
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while (!clk_system_ready(sys->regmap, sys->id))
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cpu_relax();
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return 0;
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}
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static void clk_system_unprepare(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
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}
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static int clk_system_is_prepared(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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unsigned int status;
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regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
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if (!(status & (1 << sys->id)))
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return 0;
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if (!is_pck(sys->id))
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return 1;
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regmap_read(sys->regmap, AT91_PMC_SR, &status);
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return !!(status & (1 << sys->id));
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}
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static int clk_system_save_context(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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sys->pms.status = clk_system_is_prepared(hw);
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return 0;
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}
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static void clk_system_restore_context(struct clk_hw *hw)
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{
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struct clk_system *sys = to_clk_system(hw);
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if (sys->pms.status)
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clk_system_prepare(&sys->hw);
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}
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static const struct clk_ops system_ops = {
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.prepare = clk_system_prepare,
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.unprepare = clk_system_unprepare,
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.is_prepared = clk_system_is_prepared,
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.save_context = clk_system_save_context,
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.restore_context = clk_system_restore_context,
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};
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struct clk_hw * __init
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at91_clk_register_system(struct regmap *regmap, const char *name,
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const char *parent_name, u8 id, unsigned long flags)
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{
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struct clk_system *sys;
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struct clk_hw *hw;
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struct clk_init_data init;
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int ret;
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if (!parent_name || id > SYSTEM_MAX_ID)
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return ERR_PTR(-EINVAL);
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sys = kzalloc(sizeof(*sys), GFP_KERNEL);
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if (!sys)
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return ERR_PTR(-ENOMEM);
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init.name = name;
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init.ops = &system_ops;
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init.parent_names = &parent_name;
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init.num_parents = 1;
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init.flags = CLK_SET_RATE_PARENT | flags;
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sys->id = id;
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sys->hw.init = &init;
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sys->regmap = regmap;
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hw = &sys->hw;
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ret = clk_hw_register(NULL, &sys->hw);
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if (ret) {
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kfree(sys);
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hw = ERR_PTR(ret);
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}
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return hw;
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}
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