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kernel/linux-imx6_3.14.28/arch/arm/mach-imx/clk-gate2.c 4.22 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
   * Copyright (C) 2014 Freescale Semiconductor, Inc.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * Gated clock implementation
   */
  
  #include <linux/clk-provider.h>
  #include <linux/imx_sema4.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/io.h>
  #include <linux/err.h>
  #include <linux/string.h>
  #include "clk.h"
  #include "common.h"
  
  /**
   * DOC: basic gatable clock which can gate and ungate it's ouput
   *
   * Traits of this clock:
   * prepare - clk_(un)prepare only ensures parent is (un)prepared
   * enable - clk_enable and clk_disable are functional & control gating
   * rate - inherits rate from parent.  No clk_set_rate support
   * parent - fixed parent.  No clk_set_parent support
   */
  
  struct clk_gate2 {
  	struct clk_hw hw;
  	void __iomem	*reg;
  	u8		bit_idx;
  	u8		flags;
  	spinlock_t	*lock;
  	unsigned int	*share_count;
  };
  
  #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
  #define CCM_CCGR_FULL_ENABLE	0x3
  
  static void clk_gate2_do_hardware(struct clk_gate2 *gate, bool enable)
  {
  	u32 reg;
  
  	reg = readl(gate->reg);
  	if (enable)
  		reg |= CCM_CCGR_FULL_ENABLE << gate->bit_idx;
  	else
  		reg &= ~(CCM_CCGR_FULL_ENABLE << gate->bit_idx);
  	writel(reg, gate->reg);
  }
  
  static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
  {
  	struct clk_gate2 *gate = to_clk_gate2(hw);
  
  #ifdef CONFIG_SOC_IMX6SX
  	if (imx_src_is_m4_enabled()) {
  		if (!amp_power_mutex || !shared_mem) {
  			if (enable)
  				clk_gate2_do_hardware(gate, enable);
  			return;
  		}
  
  		imx_sema4_mutex_lock(amp_power_mutex);
  		if (shared_mem->ca9_valid != SHARED_MEM_MAGIC_NUMBER ||
  			shared_mem->cm4_valid != SHARED_MEM_MAGIC_NUMBER) {
  			imx_sema4_mutex_unlock(amp_power_mutex);
  			return;
  		}
  
  		if (!imx_update_shared_mem(hw, enable)) {
  			imx_sema4_mutex_unlock(amp_power_mutex);
  			return;
  		}
  
  		clk_gate2_do_hardware(gate, enable);
  
  		imx_sema4_mutex_unlock(amp_power_mutex);
  	} else
  #endif
  	{
  		clk_gate2_do_hardware(gate, enable);
  	}
  }
  
  static int clk_gate2_enable(struct clk_hw *hw)
  {
  	struct clk_gate2 *gate = to_clk_gate2(hw);
  	unsigned long flags = 0;
  
  	spin_lock_irqsave(gate->lock, flags);
  
  	if (gate->share_count && (*gate->share_count)++ > 0)
  		goto out;
  
  	clk_gate2_do_shared_clks(hw, true);
  out:
  	spin_unlock_irqrestore(gate->lock, flags);
  
  	return 0;
  }
  
  static void clk_gate2_disable(struct clk_hw *hw)
  {
  	struct clk_gate2 *gate = to_clk_gate2(hw);
  	unsigned long flags = 0;
  
  	spin_lock_irqsave(gate->lock, flags);
  
  	if (gate->share_count) {
  		if (WARN_ON(*gate->share_count == 0))
  			goto out;
  		else if (--(*gate->share_count) > 0)
  			goto out;
  	}
  
  	clk_gate2_do_shared_clks(hw, false);
  out:
  	spin_unlock_irqrestore(gate->lock, flags);
  }
  
  static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx)
  {
  	u32 val = readl(reg);
  
  	if (((val >> bit_idx) & 1) == 1)
  		return 1;
  
  	return 0;
  }
  
  static int clk_gate2_is_enabled(struct clk_hw *hw)
  {
  	struct clk_gate2 *gate = to_clk_gate2(hw);
  
  	if (gate->share_count)
  		return !!__clk_get_enable_count(hw->clk);
  	else
  		return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx);
  }
  
  static struct clk_ops clk_gate2_ops = {
  	.enable = clk_gate2_enable,
  	.disable = clk_gate2_disable,
  	.is_enabled = clk_gate2_is_enabled,
  };
  
  struct clk *clk_register_gate2(struct device *dev, const char *name,
  		const char *parent_name, unsigned long flags,
  		void __iomem *reg, u8 bit_idx,
  		u8 clk_gate2_flags, spinlock_t *lock,
  		unsigned int *share_count)
  {
  	struct clk_gate2 *gate;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	gate = kzalloc(sizeof(struct clk_gate2), GFP_KERNEL);
  	if (!gate)
  		return ERR_PTR(-ENOMEM);
  
  	/* struct clk_gate2 assignments */
  	gate->reg = reg;
  	gate->bit_idx = bit_idx;
  	gate->flags = clk_gate2_flags;
  	gate->lock = lock;
  	gate->share_count = share_count;
  
  	init.name = name;
  	init.ops = &clk_gate2_ops;
  	init.flags = flags;
  	init.parent_names = parent_name ? &parent_name : NULL;
  	init.num_parents = parent_name ? 1 : 0;
  
  	gate->hw.init = &init;
  
  	clk = clk_register(dev, &gate->hw);
  	if (IS_ERR(clk))
  		kfree(gate);
  
  	return clk;
  }