drivers/clk/mvebu/clk-cpu.c

   1 /*
   2  * Marvell MVEBU CPU clock handling.
   3  *
   4  * Copyright (C) 2012 Marvell
   5  *
   6  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/clkdev.h>
  14 #include <linux/clk-provider.h>
  15 #include <linux/of_address.h>
  16 #include <linux/io.h>
  17 #include <linux/of.h>
  18 #include <linux/delay.h>
  19
  20 #define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET    0x0
  21 #define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET   0xC
  22 #define SYS_CTRL_CLK_DIVIDER_MASK           0x3F
  23
  24 #define MAX_CPU     4
  25 struct cpu_clk {
  26         struct clk_hw hw;
  27         int cpu;
  28         const char *clk_name;
  29         const char *parent_name;
  30         void __iomem *reg_base;
  31 };
  32
  33 static struct clk **clks;
  34
  35 static struct clk_onecell_data clk_data;
  36
  37 #define to_cpu_clk(p) container_of(p, struct cpu_clk, hw)
  38
  39 static unsigned long clk_cpu_recalc_rate(struct clk_hw *hwclk,
  40                                          unsigned long parent_rate)
  41 {
  42         struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
  43         u32 reg, div;
  44
  45         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
  46         div = (reg >> (cpuclk->cpu * 8)) & SYS_CTRL_CLK_DIVIDER_MASK;
  47         return parent_rate / div;
  48 }
  49
  50 static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate,
  51                                unsigned long *parent_rate)
  52 {
  53         /* Valid ratio are 1:1, 1:2 and 1:3 */
  54         u32 div;
  55
  56         div = *parent_rate / rate;
  57         if (div == 0)
  58                 div = 1;
  59         else if (div > 3)
  60                 div = 3;
  61
  62         return *parent_rate / div;
  63 }
  64
  65 static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
  66                             unsigned long parent_rate)
  67 {
  68         struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
  69         u32 reg, div;
  70         u32 reload_mask;
  71
  72         div = parent_rate / rate;
  73         reg = (readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET)
  74                 & (~(SYS_CTRL_CLK_DIVIDER_MASK << (cpuclk->cpu * 8))))
  75                 | (div << (cpuclk->cpu * 8));
  76         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
  77         /* Set clock divider reload smooth bit mask */
  78         reload_mask = 1 << (20 + cpuclk->cpu);
  79
  80         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
  81             | reload_mask;
  82         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
  83
  84         /* Now trigger the clock update */
  85         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
  86             | 1 << 24;
  87         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
  88
  89         /* Wait for clocks to settle down then clear reload request */
  90         udelay(1000);
  91         reg &= ~(reload_mask | 1 << 24);
  92         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
  93         udelay(1000);
  94
  95         return 0;
  96 }
  97
  98 static const struct clk_ops cpu_ops = {
  99         .recalc_rate = clk_cpu_recalc_rate,
 100         .round_rate = clk_cpu_round_rate,
 101         .set_rate = clk_cpu_set_rate,
 102 };
 103
 104 void __init of_cpu_clk_setup(struct device_node *node)
 105 {
 106         struct cpu_clk *cpuclk;
 107         void __iomem *clock_complex_base = of_iomap(node, 0);
 108         int ncpus = 0;
 109         struct device_node *dn;
 110
 111         if (clock_complex_base == NULL) {
 112                 pr_err("%s: clock-complex base register not set\n",
 113                         __func__);
 114                 return;
 115         }
 116
 117         for_each_node_by_type(dn, "cpu")
 118                 ncpus++;
 119
 120         cpuclk = kzalloc(ncpus * sizeof(*cpuclk), GFP_KERNEL);
 121         if (WARN_ON(!cpuclk))
 122                 return;
 123
 124         clks = kzalloc(ncpus * sizeof(*clks), GFP_KERNEL);
 125         if (WARN_ON(!clks))
 126                 goto clks_out;
 127
 128         for_each_node_by_type(dn, "cpu") {
 129                 struct clk_init_data init;
 130                 struct clk *clk;
 131                 struct clk *parent_clk;
 132                 char *clk_name = kzalloc(5, GFP_KERNEL);
 133                 int cpu, err;
 134
 135                 if (WARN_ON(!clk_name))
 136                         goto bail_out;
 137
 138                 err = of_property_read_u32(dn, "reg", &cpu);
 139                 if (WARN_ON(err))
 140                         goto bail_out;
 141
 142                 sprintf(clk_name, "cpu%d", cpu);
 143                 parent_clk = of_clk_get(node, 0);
 144
 145                 cpuclk[cpu].parent_name = __clk_get_name(parent_clk);
 146                 cpuclk[cpu].clk_name = clk_name;
 147                 cpuclk[cpu].cpu = cpu;
 148                 cpuclk[cpu].reg_base = clock_complex_base;
 149                 cpuclk[cpu].hw.init = &init;
 150
 151                 init.name = cpuclk[cpu].clk_name;
 152                 init.ops = &cpu_ops;
 153                 init.flags = 0;
 154                 init.parent_names = &cpuclk[cpu].parent_name;
 155                 init.num_parents = 1;
 156
 157                 clk = clk_register(NULL, &cpuclk[cpu].hw);
 158                 if (WARN_ON(IS_ERR(clk)))
 159                         goto bail_out;
 160                 clks[cpu] = clk;
 161         }
 162         clk_data.clk_num = MAX_CPU;
 163         clk_data.clks = clks;
 164         of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data);
 165
 166         return;
 167 bail_out:
 168         kfree(clks);
 169         while(ncpus--)
 170                 kfree(cpuclk[ncpus].clk_name);
 171 clks_out:
 172         kfree(cpuclk);
 173 }
 174
 175 CLK_OF_DECLARE(armada_xp_cpu_clock, "marvell,armada-xp-cpu-clock",
 176                                          of_cpu_clk_setup);