drivers/clk/mvebu/clk-cpu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Marvell MVEBU CPU clock handling.
   4  *
   5  * Copyright (C) 2012 Marvell
   6  *
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  *
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/clk.h>
  13 #include <linux/clk-provider.h>
  14 #include <linux/of_address.h>
  15 #include <linux/io.h>
  16 #include <linux/of.h>
  17 #include <linux/delay.h>
  18 #include <linux/mvebu-pmsu.h>
  19 #include <asm/smp_plat.h>
  20
  21 #define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET               0x0
  22 #define   SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL          0xff
  23 #define   SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT        8
  24 #define SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET              0x8
  25 #define   SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT 16
  26 #define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET              0xC
  27 #define SYS_CTRL_CLK_DIVIDER_MASK                      0x3F
  28
  29 #define PMU_DFS_RATIO_SHIFT 16
  30 #define PMU_DFS_RATIO_MASK  0x3F
  31
  32 #define MAX_CPU     4
  33 struct cpu_clk {
  34         struct clk_hw hw;
  35         int cpu;
  36         const char *clk_name;
  37         const char *parent_name;
  38         void __iomem *reg_base;
  39         void __iomem *pmu_dfs;
  40 };
  41
  42 static struct clk **clks;
  43
  44 static struct clk_onecell_data clk_data;
  45
  46 #define to_cpu_clk(p) container_of(p, struct cpu_clk, hw)
  47
  48 static unsigned long clk_cpu_recalc_rate(struct clk_hw *hwclk,
  49                                          unsigned long parent_rate)
  50 {
  51         struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
  52         u32 reg, div;
  53
  54         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
  55         div = (reg >> (cpuclk->cpu * 8)) & SYS_CTRL_CLK_DIVIDER_MASK;
  56         return parent_rate / div;
  57 }
  58
  59 static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate,
  60                                unsigned long *parent_rate)
  61 {
  62         /* Valid ratio are 1:1, 1:2 and 1:3 */
  63         u32 div;
  64
  65         div = *parent_rate / rate;
  66         if (div == 0)
  67                 div = 1;
  68         else if (div > 3)
  69                 div = 3;
  70
  71         return *parent_rate / div;
  72 }
  73
  74 static int clk_cpu_off_set_rate(struct clk_hw *hwclk, unsigned long rate,
  75                                 unsigned long parent_rate)
  76
  77 {
  78         struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
  79         u32 reg, div;
  80         u32 reload_mask;
  81
  82         div = parent_rate / rate;
  83         reg = (readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET)
  84                 & (~(SYS_CTRL_CLK_DIVIDER_MASK << (cpuclk->cpu * 8))))
  85                 | (div << (cpuclk->cpu * 8));
  86         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET);
  87         /* Set clock divider reload smooth bit mask */
  88         reload_mask = 1 << (20 + cpuclk->cpu);
  89
  90         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
  91             | reload_mask;
  92         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
  93
  94         /* Now trigger the clock update */
  95         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET)
  96             | 1 << 24;
  97         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
  98
  99         /* Wait for clocks to settle down then clear reload request */
 100         udelay(1000);
 101         reg &= ~(reload_mask | 1 << 24);
 102         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
 103         udelay(1000);
 104
 105         return 0;
 106 }
 107
 108 static int clk_cpu_on_set_rate(struct clk_hw *hwclk, unsigned long rate,
 109                                unsigned long parent_rate)
 110 {
 111         u32 reg;
 112         unsigned long fabric_div, target_div, cur_rate;
 113         struct cpu_clk *cpuclk = to_cpu_clk(hwclk);
 114
 115         /*
 116          * PMU DFS registers are not mapped, Device Tree does not
 117          * describes them. We cannot change the frequency dynamically.
 118          */
 119         if (!cpuclk->pmu_dfs)
 120                 return -ENODEV;
 121
 122         cur_rate = clk_hw_get_rate(hwclk);
 123
 124         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET);
 125         fabric_div = (reg >> SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT) &
 126                 SYS_CTRL_CLK_DIVIDER_MASK;
 127
 128         /* Frequency is going up */
 129         if (rate == 2 * cur_rate)
 130                 target_div = fabric_div / 2;
 131         /* Frequency is going down */
 132         else
 133                 target_div = fabric_div;
 134
 135         if (target_div == 0)
 136                 target_div = 1;
 137
 138         reg = readl(cpuclk->pmu_dfs);
 139         reg &= ~(PMU_DFS_RATIO_MASK << PMU_DFS_RATIO_SHIFT);
 140         reg |= (target_div << PMU_DFS_RATIO_SHIFT);
 141         writel(reg, cpuclk->pmu_dfs);
 142
 143         reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
 144         reg |= (SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL <<
 145                 SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT);
 146         writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET);
 147
 148         return mvebu_pmsu_dfs_request(cpuclk->cpu);
 149 }
 150
 151 static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate,
 152                             unsigned long parent_rate)
 153 {
 154         if (__clk_is_enabled(hwclk->clk))
 155                 return clk_cpu_on_set_rate(hwclk, rate, parent_rate);
 156         else
 157                 return clk_cpu_off_set_rate(hwclk, rate, parent_rate);
 158 }
 159
 160 static const struct clk_ops cpu_ops = {
 161         .recalc_rate = clk_cpu_recalc_rate,
 162         .round_rate = clk_cpu_round_rate,
 163         .set_rate = clk_cpu_set_rate,
 164 };
 165
 166 static void __init of_cpu_clk_setup(struct device_node *node)
 167 {
 168         struct cpu_clk *cpuclk;
 169         void __iomem *clock_complex_base = of_iomap(node, 0);
 170         void __iomem *pmu_dfs_base = of_iomap(node, 1);
 171         int ncpus = num_possible_cpus();
 172         int cpu;
 173
 174         if (clock_complex_base == NULL) {
 175                 pr_err("%s: clock-complex base register not set\n",
 176                         __func__);
 177                 return;
 178         }
 179
 180         if (pmu_dfs_base == NULL)
 181                 pr_warn("%s: pmu-dfs base register not set, dynamic frequency scaling not available\n",
 182                         __func__);
 183
 184         cpuclk = kcalloc(ncpus, sizeof(*cpuclk), GFP_KERNEL);
 185         if (WARN_ON(!cpuclk))
 186                 goto cpuclk_out;
 187
 188         clks = kcalloc(ncpus, sizeof(*clks), GFP_KERNEL);
 189         if (WARN_ON(!clks))
 190                 goto clks_out;
 191
 192         for_each_possible_cpu(cpu) {
 193                 struct clk_init_data init;
 194                 struct clk *clk;
 195                 char *clk_name = kzalloc(5, GFP_KERNEL);
 196
 197                 if (WARN_ON(!clk_name))
 198                         goto bail_out;
 199
 200                 sprintf(clk_name, "cpu%d", cpu);
 201
 202                 cpuclk[cpu].parent_name = of_clk_get_parent_name(node, 0);
 203                 cpuclk[cpu].clk_name = clk_name;
 204                 cpuclk[cpu].cpu = cpu;
 205                 cpuclk[cpu].reg_base = clock_complex_base;
 206                 if (pmu_dfs_base)
 207                         cpuclk[cpu].pmu_dfs = pmu_dfs_base + 4 * cpu;
 208                 cpuclk[cpu].hw.init = &init;
 209
 210                 init.name = cpuclk[cpu].clk_name;
 211                 init.ops = &cpu_ops;
 212                 init.flags = 0;
 213                 init.parent_names = &cpuclk[cpu].parent_name;
 214                 init.num_parents = 1;
 215
 216                 clk = clk_register(NULL, &cpuclk[cpu].hw);
 217                 if (WARN_ON(IS_ERR(clk)))
 218                         goto bail_out;
 219                 clks[cpu] = clk;
 220         }
 221         clk_data.clk_num = MAX_CPU;
 222         clk_data.clks = clks;
 223         of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data);
 224
 225         return;
 226 bail_out:
 227         kfree(clks);
 228         while(ncpus--)
 229                 kfree(cpuclk[ncpus].clk_name);
 230 clks_out:
 231         kfree(cpuclk);
 232 cpuclk_out:
 233         iounmap(clock_complex_base);
 234 }
 235
 236 CLK_OF_DECLARE(armada_xp_cpu_clock, "marvell,armada-xp-cpu-clock",
 237                                          of_cpu_clk_setup);
 238
 239 static void __init of_mv98dx3236_cpu_clk_setup(struct device_node *node)
 240 {
 241         of_clk_add_provider(node, of_clk_src_simple_get, NULL);
 242 }
 243
 244 CLK_OF_DECLARE(mv98dx3236_cpu_clock, "marvell,mv98dx3236-cpu-clock",
 245                                          of_mv98dx3236_cpu_clk_setup);