![Martin Blumenstingl](/assets/img/avatar_default.png)
On Meson8b the MPLL parent clock (fixed_pll) has a rate of 2550MHz.
Multiplying this with SDM_DEN results in a value greater than 32bits.
This is not a problem on the 64bit Meson GX SoCs, but it may result in
undefined behavior on the older 32bit Meson8b SoC.
While rate_from_params was only introduced recently to make the math
reusable from _round_rate and _recalc_rate the original bug exists much
longer.
Fixes: 1c50da4f27
("clk: meson: add mpll support")
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[as discussed on the ml, use DIV_ROUND_UP_ULL]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
241 lines
6.5 KiB
C
241 lines
6.5 KiB
C
/*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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*
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* Copyright (c) 2016 AmLogic, Inc.
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* Author: Michael Turquette <mturquette@baylibre.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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* The full GNU General Public License is included in this distribution
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* in the file called COPYING
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*
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* BSD LICENSE
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*
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* Copyright (c) 2016 AmLogic, Inc.
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* Author: Michael Turquette <mturquette@baylibre.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* MultiPhase Locked Loops are outputs from a PLL with additional frequency
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* scaling capabilities. MPLL rates are calculated as:
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*
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* f(N2_integer, SDM_IN ) = 2.0G/(N2_integer + SDM_IN/16384)
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*/
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#include <linux/clk-provider.h>
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#include "clkc.h"
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#define SDM_DEN 16384
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#define N2_MIN 4
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#define N2_MAX 511
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#define to_meson_clk_mpll(_hw) container_of(_hw, struct meson_clk_mpll, hw)
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static long rate_from_params(unsigned long parent_rate,
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unsigned long sdm,
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unsigned long n2)
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{
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unsigned long divisor = (SDM_DEN * n2) + sdm;
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if (n2 < N2_MIN)
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return -EINVAL;
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return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor);
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}
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static void params_from_rate(unsigned long requested_rate,
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unsigned long parent_rate,
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unsigned long *sdm,
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unsigned long *n2)
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{
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uint64_t div = parent_rate;
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unsigned long rem = do_div(div, requested_rate);
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if (div < N2_MIN) {
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*n2 = N2_MIN;
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*sdm = 0;
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} else if (div > N2_MAX) {
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*n2 = N2_MAX;
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*sdm = SDM_DEN - 1;
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} else {
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*n2 = div;
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*sdm = DIV_ROUND_UP(rem * SDM_DEN, requested_rate);
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}
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}
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static unsigned long mpll_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
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struct parm *p;
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unsigned long reg, sdm, n2;
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long rate;
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p = &mpll->sdm;
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reg = readl(mpll->base + p->reg_off);
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sdm = PARM_GET(p->width, p->shift, reg);
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p = &mpll->n2;
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reg = readl(mpll->base + p->reg_off);
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n2 = PARM_GET(p->width, p->shift, reg);
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rate = rate_from_params(parent_rate, sdm, n2);
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if (rate < 0)
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return 0;
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return rate;
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}
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static long mpll_round_rate(struct clk_hw *hw,
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unsigned long rate,
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unsigned long *parent_rate)
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{
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unsigned long sdm, n2;
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params_from_rate(rate, *parent_rate, &sdm, &n2);
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return rate_from_params(*parent_rate, sdm, n2);
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}
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static int mpll_set_rate(struct clk_hw *hw,
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unsigned long rate,
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unsigned long parent_rate)
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{
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struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
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struct parm *p;
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unsigned long reg, sdm, n2;
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unsigned long flags = 0;
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params_from_rate(rate, parent_rate, &sdm, &n2);
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if (mpll->lock)
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spin_lock_irqsave(mpll->lock, flags);
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else
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__acquire(mpll->lock);
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p = &mpll->sdm;
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reg = readl(mpll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, sdm);
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writel(reg, mpll->base + p->reg_off);
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p = &mpll->sdm_en;
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reg = readl(mpll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, 1);
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writel(reg, mpll->base + p->reg_off);
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p = &mpll->n2;
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reg = readl(mpll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, n2);
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writel(reg, mpll->base + p->reg_off);
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if (mpll->lock)
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spin_unlock_irqrestore(mpll->lock, flags);
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else
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__release(mpll->lock);
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return 0;
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}
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static void mpll_enable_core(struct clk_hw *hw, int enable)
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{
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struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
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struct parm *p;
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unsigned long reg;
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unsigned long flags = 0;
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if (mpll->lock)
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spin_lock_irqsave(mpll->lock, flags);
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else
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__acquire(mpll->lock);
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p = &mpll->en;
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reg = readl(mpll->base + p->reg_off);
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reg = PARM_SET(p->width, p->shift, reg, enable ? 1 : 0);
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writel(reg, mpll->base + p->reg_off);
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if (mpll->lock)
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spin_unlock_irqrestore(mpll->lock, flags);
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else
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__release(mpll->lock);
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}
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static int mpll_enable(struct clk_hw *hw)
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{
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mpll_enable_core(hw, 1);
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return 0;
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}
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static void mpll_disable(struct clk_hw *hw)
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{
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mpll_enable_core(hw, 0);
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}
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static int mpll_is_enabled(struct clk_hw *hw)
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{
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struct meson_clk_mpll *mpll = to_meson_clk_mpll(hw);
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struct parm *p;
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unsigned long reg;
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int en;
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p = &mpll->en;
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reg = readl(mpll->base + p->reg_off);
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en = PARM_GET(p->width, p->shift, reg);
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return en;
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}
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const struct clk_ops meson_clk_mpll_ro_ops = {
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.recalc_rate = mpll_recalc_rate,
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.round_rate = mpll_round_rate,
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.is_enabled = mpll_is_enabled,
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};
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const struct clk_ops meson_clk_mpll_ops = {
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.recalc_rate = mpll_recalc_rate,
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.round_rate = mpll_round_rate,
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.set_rate = mpll_set_rate,
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.enable = mpll_enable,
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.disable = mpll_disable,
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.is_enabled = mpll_is_enabled,
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};
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