drivers/clk/mvebu/common.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Marvell EBU SoC common clock handling
   4  *
   5  * Copyright (C) 2012 Marvell
   6  *
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
   9  * Andrew Lunn <andrew@lunn.ch>
  10  *
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/clk.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/syscore_ops.h>
  21
  22 #include "common.h"
  23
  24 /*
  25  * Core Clocks
  26  */
  27
  28 #define SSCG_CONF_MODE(reg)     (((reg) >> 16) & 0x3)
  29 #define SSCG_SPREAD_DOWN        0x0
  30 #define SSCG_SPREAD_UP          0x1
  31 #define SSCG_SPREAD_CENTRAL     0x2
  32 #define SSCG_CONF_LOW(reg)      (((reg) >> 8) & 0xFF)
  33 #define SSCG_CONF_HIGH(reg)     ((reg) & 0xFF)
  34
  35 static struct clk_onecell_data clk_data;
  36
  37 /*
  38  * This function can be used by the Kirkwood, the Armada 370, the
  39  * Armada XP and the Armada 375 SoC. The name of the function was
  40  * chosen following the dt convention: using the first known SoC
  41  * compatible with it.
  42  */
  43 u32 kirkwood_fix_sscg_deviation(u32 system_clk)
  44 {
  45         struct device_node *sscg_np = NULL;
  46         void __iomem *sscg_map;
  47         u32 sscg_reg;
  48         s32 low_bound, high_bound;
  49         u64 freq_swing_half;
  50
  51         sscg_np = of_find_node_by_name(NULL, "sscg");
  52         if (sscg_np == NULL) {
  53                 pr_err("cannot get SSCG register node\n");
  54                 return system_clk;
  55         }
  56
  57         sscg_map = of_iomap(sscg_np, 0);
  58         if (sscg_map == NULL) {
  59                 pr_err("cannot map SSCG register\n");
  60                 goto out;
  61         }
  62
  63         sscg_reg = readl(sscg_map);
  64         high_bound = SSCG_CONF_HIGH(sscg_reg);
  65         low_bound = SSCG_CONF_LOW(sscg_reg);
  66
  67         if ((high_bound - low_bound) <= 0)
  68                 goto out;
  69         /*
  70          * From Marvell engineer we got the following formula (when
  71          * this code was written, the datasheet was erroneous)
  72          * Spread percentage = 1/96 * (H - L) / H
  73          * H = SSCG_High_Boundary
  74          * L = SSCG_Low_Boundary
  75          *
  76          * As the deviation is half of spread then it lead to the
  77          * following formula in the code.
  78          *
  79          * To avoid an overflow and not lose any significant digit in
  80          * the same time we have to use a 64 bit integer.
  81          */
  82
  83         freq_swing_half = (((u64)high_bound - (u64)low_bound)
  84                         * (u64)system_clk);
  85         do_div(freq_swing_half, (2 * 96 * high_bound));
  86
  87         switch (SSCG_CONF_MODE(sscg_reg)) {
  88         case SSCG_SPREAD_DOWN:
  89                 system_clk -= freq_swing_half;
  90                 break;
  91         case SSCG_SPREAD_UP:
  92                 system_clk += freq_swing_half;
  93                 break;
  94         case SSCG_SPREAD_CENTRAL:
  95         default:
  96                 break;
  97         }
  98
  99         iounmap(sscg_map);
 100
 101 out:
 102         of_node_put(sscg_np);
 103
 104         return system_clk;
 105 }
 106
 107 void __init mvebu_coreclk_setup(struct device_node *np,
 108                                 const struct coreclk_soc_desc *desc)
 109 {
 110         const char *tclk_name = "tclk";
 111         const char *cpuclk_name = "cpuclk";
 112         void __iomem *base;
 113         unsigned long rate;
 114         int n;
 115
 116         base = of_iomap(np, 0);
 117         if (WARN_ON(!base))
 118                 return;
 119
 120         /* Allocate struct for TCLK, cpu clk, and core ratio clocks */
 121         clk_data.clk_num = 2 + desc->num_ratios;
 122
 123         /* One more clock for the optional refclk */
 124         if (desc->get_refclk_freq)
 125                 clk_data.clk_num += 1;
 126
 127         clk_data.clks = kcalloc(clk_data.clk_num, sizeof(*clk_data.clks),
 128                                 GFP_KERNEL);
 129         if (WARN_ON(!clk_data.clks)) {
 130                 iounmap(base);
 131                 return;
 132         }
 133
 134         /* Register TCLK */
 135         of_property_read_string_index(np, "clock-output-names", 0,
 136                                       &tclk_name);
 137         rate = desc->get_tclk_freq(base);
 138         clk_data.clks[0] = clk_register_fixed_rate(NULL, tclk_name, NULL, 0,
 139                                                    rate);
 140         WARN_ON(IS_ERR(clk_data.clks[0]));
 141
 142         /* Register CPU clock */
 143         of_property_read_string_index(np, "clock-output-names", 1,
 144                                       &cpuclk_name);
 145         rate = desc->get_cpu_freq(base);
 146
 147         if (desc->is_sscg_enabled && desc->fix_sscg_deviation
 148                 && desc->is_sscg_enabled(base))
 149                 rate = desc->fix_sscg_deviation(rate);
 150
 151         clk_data.clks[1] = clk_register_fixed_rate(NULL, cpuclk_name, NULL, 0,
 152                                                    rate);
 153         WARN_ON(IS_ERR(clk_data.clks[1]));
 154
 155         /* Register fixed-factor clocks derived from CPU clock */
 156         for (n = 0; n < desc->num_ratios; n++) {
 157                 const char *rclk_name = desc->ratios[n].name;
 158                 int mult, div;
 159
 160                 of_property_read_string_index(np, "clock-output-names",
 161                                               2+n, &rclk_name);
 162                 desc->get_clk_ratio(base, desc->ratios[n].id, &mult, &div);
 163                 clk_data.clks[2+n] = clk_register_fixed_factor(NULL, rclk_name,
 164                                        cpuclk_name, 0, mult, div);
 165                 WARN_ON(IS_ERR(clk_data.clks[2+n]));
 166         }
 167
 168         /* Register optional refclk */
 169         if (desc->get_refclk_freq) {
 170                 const char *name = "refclk";
 171                 of_property_read_string_index(np, "clock-output-names",
 172                                               2 + desc->num_ratios, &name);
 173                 rate = desc->get_refclk_freq(base);
 174                 clk_data.clks[2 + desc->num_ratios] =
 175                         clk_register_fixed_rate(NULL, name, NULL, 0, rate);
 176                 WARN_ON(IS_ERR(clk_data.clks[2 + desc->num_ratios]));
 177         }
 178
 179         /* SAR register isn't needed anymore */
 180         iounmap(base);
 181
 182         of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 183 }
 184
 185 /*
 186  * Clock Gating Control
 187  */
 188
 189 DEFINE_SPINLOCK(ctrl_gating_lock);
 190
 191 struct clk_gating_ctrl {
 192         spinlock_t *lock;
 193         struct clk **gates;
 194         int num_gates;
 195         void __iomem *base;
 196         u32 saved_reg;
 197 };
 198
 199 static struct clk_gating_ctrl *ctrl;
 200
 201 static struct clk *clk_gating_get_src(
 202         struct of_phandle_args *clkspec, void *data)
 203 {
 204         int n;
 205
 206         if (clkspec->args_count < 1)
 207                 return ERR_PTR(-EINVAL);
 208
 209         for (n = 0; n < ctrl->num_gates; n++) {
 210                 struct clk_gate *gate =
 211                         to_clk_gate(__clk_get_hw(ctrl->gates[n]));
 212                 if (clkspec->args[0] == gate->bit_idx)
 213                         return ctrl->gates[n];
 214         }
 215         return ERR_PTR(-ENODEV);
 216 }
 217
 218 static int mvebu_clk_gating_suspend(void)
 219 {
 220         ctrl->saved_reg = readl(ctrl->base);
 221         return 0;
 222 }
 223
 224 static void mvebu_clk_gating_resume(void)
 225 {
 226         writel(ctrl->saved_reg, ctrl->base);
 227 }
 228
 229 static struct syscore_ops clk_gate_syscore_ops = {
 230         .suspend = mvebu_clk_gating_suspend,
 231         .resume = mvebu_clk_gating_resume,
 232 };
 233
 234 void __init mvebu_clk_gating_setup(struct device_node *np,
 235                                    const struct clk_gating_soc_desc *desc)
 236 {
 237         struct clk *clk;
 238         void __iomem *base;
 239         const char *default_parent = NULL;
 240         int n;
 241
 242         if (ctrl) {
 243                 pr_err("mvebu-clk-gating: cannot instantiate more than one gateable clock device\n");
 244                 return;
 245         }
 246
 247         base = of_iomap(np, 0);
 248         if (WARN_ON(!base))
 249                 return;
 250
 251         clk = of_clk_get(np, 0);
 252         if (!IS_ERR(clk)) {
 253                 default_parent = __clk_get_name(clk);
 254                 clk_put(clk);
 255         }
 256
 257         ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
 258         if (WARN_ON(!ctrl))
 259                 goto ctrl_out;
 260
 261         /* lock must already be initialized */
 262         ctrl->lock = &ctrl_gating_lock;
 263
 264         ctrl->base = base;
 265
 266         /* Count, allocate, and register clock gates */
 267         for (n = 0; desc[n].name;)
 268                 n++;
 269
 270         ctrl->num_gates = n;
 271         ctrl->gates = kcalloc(ctrl->num_gates, sizeof(*ctrl->gates),
 272                               GFP_KERNEL);
 273         if (WARN_ON(!ctrl->gates))
 274                 goto gates_out;
 275
 276         for (n = 0; n < ctrl->num_gates; n++) {
 277                 const char *parent =
 278                         (desc[n].parent) ? desc[n].parent : default_parent;
 279                 ctrl->gates[n] = clk_register_gate(NULL, desc[n].name, parent,
 280                                         desc[n].flags, base, desc[n].bit_idx,
 281                                         0, ctrl->lock);
 282                 WARN_ON(IS_ERR(ctrl->gates[n]));
 283         }
 284
 285         of_clk_add_provider(np, clk_gating_get_src, ctrl);
 286
 287         register_syscore_ops(&clk_gate_syscore_ops);
 288
 289         return;
 290 gates_out:
 291         kfree(ctrl);
 292 ctrl_out:
 293         iounmap(base);
 294 }