249 lines
6.5 KiB
C
249 lines
6.5 KiB
C
/*
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* Marvell MVEBU CPU clock handling.
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*
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* Copyright (C) 2012 Marvell
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*
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* Gregory CLEMENT <gregory.clement@free-electrons.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/kernel.h>
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#include <linux/clkdev.h>
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#include <linux/clk-provider.h>
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#include <linux/of_address.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/delay.h>
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#include <linux/mvebu-pmsu.h>
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#include <asm/smp_plat.h>
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#define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET 0x0
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#define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL 0xff
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#define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT 8
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#define SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET 0x8
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#define SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT 16
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#define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET 0xC
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#define SYS_CTRL_CLK_DIVIDER_MASK 0x3F
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#define PMU_DFS_RATIO_SHIFT 16
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#define PMU_DFS_RATIO_MASK 0x3F
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#define MAX_CPU 4
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struct cpu_clk {
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struct clk_hw hw;
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int cpu;
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const char *clk_name;
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const char *parent_name;
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void __iomem *reg_base;
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void __iomem *pmu_dfs;
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};
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static struct clk **clks;
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static struct clk_onecell_data clk_data;
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#define to_cpu_clk(p) container_of(p, struct cpu_clk, hw)
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static unsigned long clk_cpu_recalc_rate(struct clk_hw *hwclk,
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unsigned long parent_rate)
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{
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struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
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u32 reg, div;
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reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
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div = (reg >> (cpuclk->cpu * 8)) & SYS_CTRL_CLK_DIVIDER_MASK;
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return parent_rate / div;
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}
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static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate,
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unsigned long *parent_rate)
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{
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/* Valid ratio are 1:1, 1:2 and 1:3 */
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u32 div;
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div = *parent_rate / rate;
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if (div == 0)
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div = 1;
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else if (div > 3)
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div = 3;
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return *parent_rate / div;
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}
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static int clk_cpu_off_set_rate(struct clk_hw *hwclk, unsigned long rate,
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unsigned long parent_rate)
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{
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struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
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u32 reg, div;
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u32 reload_mask;
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div = parent_rate / rate;
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reg = (readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET)
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& (~(SYS_CTRL_CLK_DIVIDER_MASK << (cpuclk->cpu * 8))))
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| (div << (cpuclk->cpu * 8));
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writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
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/* Set clock divider reload smooth bit mask */
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reload_mask = 1 << (20 + cpuclk->cpu);
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reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
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| reload_mask;
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writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
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/* Now trigger the clock update */
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reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
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| 1 << 24;
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writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
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/* Wait for clocks to settle down then clear reload request */
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udelay(1000);
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reg &= ~(reload_mask | 1 << 24);
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writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
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udelay(1000);
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return 0;
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}
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static int clk_cpu_on_set_rate(struct clk_hw *hwclk, unsigned long rate,
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unsigned long parent_rate)
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{
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u32 reg;
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unsigned long fabric_div, target_div, cur_rate;
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struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
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/*
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* PMU DFS registers are not mapped, Device Tree does not
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* describes them. We cannot change the frequency dynamically.
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*/
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if (!cpuclk->pmu_dfs)
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return -ENODEV;
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cur_rate = __clk_get_rate(hwclk->clk);
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reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET);
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fabric_div = (reg >> SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT) &
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SYS_CTRL_CLK_DIVIDER_MASK;
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/* Frequency is going up */
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if (rate == 2 * cur_rate)
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target_div = fabric_div / 2;
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/* Frequency is going down */
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else
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target_div = fabric_div;
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if (target_div == 0)
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target_div = 1;
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reg = readl(cpuclk->pmu_dfs);
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reg &= ~(PMU_DFS_RATIO_MASK << PMU_DFS_RATIO_SHIFT);
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reg |= (target_div << PMU_DFS_RATIO_SHIFT);
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writel(reg, cpuclk->pmu_dfs);
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reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
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reg |= (SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL <<
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SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT);
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writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
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return mvebu_pmsu_dfs_request(cpuclk->cpu);
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}
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static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
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unsigned long parent_rate)
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{
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if (__clk_is_enabled(hwclk->clk))
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return clk_cpu_on_set_rate(hwclk, rate, parent_rate);
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else
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return clk_cpu_off_set_rate(hwclk, rate, parent_rate);
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}
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static const struct clk_ops cpu_ops = {
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.recalc_rate = clk_cpu_recalc_rate,
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.round_rate = clk_cpu_round_rate,
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.set_rate = clk_cpu_set_rate,
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};
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static void __init of_cpu_clk_setup(struct device_node *node)
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{
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struct cpu_clk *cpuclk;
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void __iomem *clock_complex_base = of_iomap(node, 0);
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void __iomem *pmu_dfs_base = of_iomap(node, 1);
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int ncpus = 0;
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struct device_node *dn;
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if (clock_complex_base == NULL) {
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pr_err("%s: clock-complex base register not set\n",
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__func__);
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return;
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}
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if (pmu_dfs_base == NULL)
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pr_warn("%s: pmu-dfs base register not set, dynamic frequency scaling not available\n",
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__func__);
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for_each_node_by_type(dn, "cpu")
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ncpus++;
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cpuclk = kzalloc(ncpus * sizeof(*cpuclk), GFP_KERNEL);
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if (WARN_ON(!cpuclk))
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goto cpuclk_out;
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clks = kzalloc(ncpus * sizeof(*clks), GFP_KERNEL);
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if (WARN_ON(!clks))
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goto clks_out;
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for_each_node_by_type(dn, "cpu") {
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struct clk_init_data init;
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struct clk *clk;
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struct clk *parent_clk;
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char *clk_name = kzalloc(5, GFP_KERNEL);
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int cpu, err;
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if (WARN_ON(!clk_name))
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goto bail_out;
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err = of_property_read_u32(dn, "reg", &cpu);
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if (WARN_ON(err))
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goto bail_out;
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sprintf(clk_name, "cpu%d", cpu);
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parent_clk = of_clk_get(node, 0);
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cpuclk[cpu].parent_name = __clk_get_name(parent_clk);
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cpuclk[cpu].clk_name = clk_name;
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cpuclk[cpu].cpu = cpu;
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cpuclk[cpu].reg_base = clock_complex_base;
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if (pmu_dfs_base)
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cpuclk[cpu].pmu_dfs = pmu_dfs_base + 4 * cpu;
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cpuclk[cpu].hw.init = &init;
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init.name = cpuclk[cpu].clk_name;
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init.ops = &cpu_ops;
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init.flags = 0;
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init.parent_names = &cpuclk[cpu].parent_name;
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init.num_parents = 1;
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clk = clk_register(NULL, &cpuclk[cpu].hw);
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if (WARN_ON(IS_ERR(clk)))
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goto bail_out;
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clks[cpu] = clk;
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}
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clk_data.clk_num = MAX_CPU;
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clk_data.clks = clks;
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of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data);
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return;
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bail_out:
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kfree(clks);
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while(ncpus--)
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kfree(cpuclk[ncpus].clk_name);
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clks_out:
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kfree(cpuclk);
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cpuclk_out:
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iounmap(clock_complex_base);
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}
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CLK_OF_DECLARE(armada_xp_cpu_clock, "marvell,armada-xp-cpu-clock",
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of_cpu_clk_setup);
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