drivers/clk/mvebu/common.c

   1 /*
   2  * Marvell EBU SoC common clock handling
   3  *
   4  * Copyright (C) 2012 Marvell
   5  *
   6  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   7  * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
   8  * Andrew Lunn <andrew@lunn.ch>
   9  *
  10  * This file is licensed under the terms of the GNU General Public
  11  * License version 2.  This program is licensed "as is" without any
  12  * warranty of any kind, whether express or implied.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/clk.h>
  17 #include <linux/clkdev.h>
  18 #include <linux/clk-provider.h>
  19 #include <linux/io.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/syscore_ops.h>
  23
  24 #include "common.h"
  25
  26 /*
  27  * Core Clocks
  28  */
  29
  30 #define SSCG_CONF_MODE(reg)     (((reg) >> 16) & 0x3)
  31 #define SSCG_SPREAD_DOWN        0x0
  32 #define SSCG_SPREAD_UP          0x1
  33 #define SSCG_SPREAD_CENTRAL     0x2
  34 #define SSCG_CONF_LOW(reg)      (((reg) >> 8) & 0xFF)
  35 #define SSCG_CONF_HIGH(reg)     ((reg) & 0xFF)
  36
  37 static struct clk_onecell_data clk_data;
  38
  39 /*
  40  * This function can be used by the Kirkwood, the Armada 370, the
  41  * Armada XP and the Armada 375 SoC. The name of the function was
  42  * chosen following the dt convention: using the first known SoC
  43  * compatible with it.
  44  */
  45 u32 kirkwood_fix_sscg_deviation(u32 system_clk)
  46 {
  47         struct device_node *sscg_np = NULL;
  48         void __iomem *sscg_map;
  49         u32 sscg_reg;
  50         s32 low_bound, high_bound;
  51         u64 freq_swing_half;
  52
  53         sscg_np = of_find_node_by_name(NULL, "sscg");
  54         if (sscg_np == NULL) {
  55                 pr_err("cannot get SSCG register node\n");
  56                 return system_clk;
  57         }
  58
  59         sscg_map = of_iomap(sscg_np, 0);
  60         if (sscg_map == NULL) {
  61                 pr_err("cannot map SSCG register\n");
  62                 goto out;
  63         }
  64
  65         sscg_reg = readl(sscg_map);
  66         high_bound = SSCG_CONF_HIGH(sscg_reg);
  67         low_bound = SSCG_CONF_LOW(sscg_reg);
  68
  69         if ((high_bound - low_bound) <= 0)
  70                 goto out;
  71         /*
  72          * From Marvell engineer we got the following formula (when
  73          * this code was written, the datasheet was erroneous)
  74          * Spread percentage = 1/96 * (H - L) / H
  75          * H = SSCG_High_Boundary
  76          * L = SSCG_Low_Boundary
  77          *
  78          * As the deviation is half of spread then it lead to the
  79          * following formula in the code.
  80          *
  81          * To avoid an overflow and not lose any significant digit in
  82          * the same time we have to use a 64 bit integer.
  83          */
  84
  85         freq_swing_half = (((u64)high_bound - (u64)low_bound)
  86                         * (u64)system_clk);
  87         do_div(freq_swing_half, (2 * 96 * high_bound));
  88
  89         switch (SSCG_CONF_MODE(sscg_reg)) {
  90         case SSCG_SPREAD_DOWN:
  91                 system_clk -= freq_swing_half;
  92                 break;
  93         case SSCG_SPREAD_UP:
  94                 system_clk += freq_swing_half;
  95                 break;
  96         case SSCG_SPREAD_CENTRAL:
  97         default:
  98                 break;
  99         }
 100
 101         iounmap(sscg_map);
 102
 103 out:
 104         of_node_put(sscg_np);
 105
 106         return system_clk;
 107 }
 108
 109 void __init mvebu_coreclk_setup(struct device_node *np,
 110                                 const struct coreclk_soc_desc *desc)
 111 {
 112         const char *tclk_name = "tclk";
 113         const char *cpuclk_name = "cpuclk";
 114         void __iomem *base;
 115         unsigned long rate;
 116         int n;
 117
 118         base = of_iomap(np, 0);
 119         if (WARN_ON(!base))
 120                 return;
 121
 122         /* Allocate struct for TCLK, cpu clk, and core ratio clocks */
 123         clk_data.clk_num = 2 + desc->num_ratios;
 124
 125         /* One more clock for the optional refclk */
 126         if (desc->get_refclk_freq)
 127                 clk_data.clk_num += 1;
 128
 129         clk_data.clks = kzalloc(clk_data.clk_num * sizeof(struct clk *),
 130                                 GFP_KERNEL);
 131         if (WARN_ON(!clk_data.clks)) {
 132                 iounmap(base);
 133                 return;
 134         }
 135
 136         /* Register TCLK */
 137         of_property_read_string_index(np, "clock-output-names", 0,
 138                                       &tclk_name);
 139         rate = desc->get_tclk_freq(base);
 140         clk_data.clks[0] = clk_register_fixed_rate(NULL, tclk_name, NULL,
 141                                                    CLK_IS_ROOT, rate);
 142         WARN_ON(IS_ERR(clk_data.clks[0]));
 143
 144         /* Register CPU clock */
 145         of_property_read_string_index(np, "clock-output-names", 1,
 146                                       &cpuclk_name);
 147         rate = desc->get_cpu_freq(base);
 148
 149         if (desc->is_sscg_enabled && desc->fix_sscg_deviation
 150                 && desc->is_sscg_enabled(base))
 151                 rate = desc->fix_sscg_deviation(rate);
 152
 153         clk_data.clks[1] = clk_register_fixed_rate(NULL, cpuclk_name, NULL,
 154                                                    CLK_IS_ROOT, rate);
 155         WARN_ON(IS_ERR(clk_data.clks[1]));
 156
 157         /* Register fixed-factor clocks derived from CPU clock */
 158         for (n = 0; n < desc->num_ratios; n++) {
 159                 const char *rclk_name = desc->ratios[n].name;
 160                 int mult, div;
 161
 162                 of_property_read_string_index(np, "clock-output-names",
 163                                               2+n, &rclk_name);
 164                 desc->get_clk_ratio(base, desc->ratios[n].id, &mult, &div);
 165                 clk_data.clks[2+n] = clk_register_fixed_factor(NULL, rclk_name,
 166                                        cpuclk_name, 0, mult, div);
 167                 WARN_ON(IS_ERR(clk_data.clks[2+n]));
 168         };
 169
 170         /* Register optional refclk */
 171         if (desc->get_refclk_freq) {
 172                 const char *name = "refclk";
 173                 of_property_read_string_index(np, "clock-output-names",
 174                                               2 + desc->num_ratios, &name);
 175                 rate = desc->get_refclk_freq(base);
 176                 clk_data.clks[2 + desc->num_ratios] =
 177                         clk_register_fixed_rate(NULL, name, NULL,
 178                                                 CLK_IS_ROOT, rate);
 179                 WARN_ON(IS_ERR(clk_data.clks[2 + desc->num_ratios]));
 180         }
 181
 182         /* SAR register isn't needed anymore */
 183         iounmap(base);
 184
 185         of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
 186 }
 187
 188 /*
 189  * Clock Gating Control
 190  */
 191
 192 DEFINE_SPINLOCK(ctrl_gating_lock);
 193
 194 struct clk_gating_ctrl {
 195         spinlock_t *lock;
 196         struct clk **gates;
 197         int num_gates;
 198         void __iomem *base;
 199         u32 saved_reg;
 200 };
 201
 202 #define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
 203
 204 static struct clk_gating_ctrl *ctrl;
 205
 206 static struct clk *clk_gating_get_src(
 207         struct of_phandle_args *clkspec, void *data)
 208 {
 209         int n;
 210
 211         if (clkspec->args_count < 1)
 212                 return ERR_PTR(-EINVAL);
 213
 214         for (n = 0; n < ctrl->num_gates; n++) {
 215                 struct clk_gate *gate =
 216                         to_clk_gate(__clk_get_hw(ctrl->gates[n]));
 217                 if (clkspec->args[0] == gate->bit_idx)
 218                         return ctrl->gates[n];
 219         }
 220         return ERR_PTR(-ENODEV);
 221 }
 222
 223 static int mvebu_clk_gating_suspend(void)
 224 {
 225         ctrl->saved_reg = readl(ctrl->base);
 226         return 0;
 227 }
 228
 229 static void mvebu_clk_gating_resume(void)
 230 {
 231         writel(ctrl->saved_reg, ctrl->base);
 232 }
 233
 234 static struct syscore_ops clk_gate_syscore_ops = {
 235         .suspend = mvebu_clk_gating_suspend,
 236         .resume = mvebu_clk_gating_resume,
 237 };
 238
 239 void __init mvebu_clk_gating_setup(struct device_node *np,
 240                                    const struct clk_gating_soc_desc *desc)
 241 {
 242         struct clk *clk;
 243         void __iomem *base;
 244         const char *default_parent = NULL;
 245         int n;
 246
 247         if (ctrl) {
 248                 pr_err("mvebu-clk-gating: cannot instantiate more than one gatable clock device\n");
 249                 return;
 250         }
 251
 252         base = of_iomap(np, 0);
 253         if (WARN_ON(!base))
 254                 return;
 255
 256         clk = of_clk_get(np, 0);
 257         if (!IS_ERR(clk)) {
 258                 default_parent = __clk_get_name(clk);
 259                 clk_put(clk);
 260         }
 261
 262         ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
 263         if (WARN_ON(!ctrl))
 264                 goto ctrl_out;
 265
 266         /* lock must already be initialized */
 267         ctrl->lock = &ctrl_gating_lock;
 268
 269         ctrl->base = base;
 270
 271         /* Count, allocate, and register clock gates */
 272         for (n = 0; desc[n].name;)
 273                 n++;
 274
 275         ctrl->num_gates = n;
 276         ctrl->gates = kzalloc(ctrl->num_gates * sizeof(struct clk *),
 277                               GFP_KERNEL);
 278         if (WARN_ON(!ctrl->gates))
 279                 goto gates_out;
 280
 281         for (n = 0; n < ctrl->num_gates; n++) {
 282                 const char *parent =
 283                         (desc[n].parent) ? desc[n].parent : default_parent;
 284                 ctrl->gates[n] = clk_register_gate(NULL, desc[n].name, parent,
 285                                         desc[n].flags, base, desc[n].bit_idx,
 286                                         0, ctrl->lock);
 287                 WARN_ON(IS_ERR(ctrl->gates[n]));
 288         }
 289
 290         of_clk_add_provider(np, clk_gating_get_src, ctrl);
 291
 292         register_syscore_ops(&clk_gate_syscore_ops);
 293
 294         return;
 295 gates_out:
 296         kfree(ctrl);
 297 ctrl_out:
 298         iounmap(base);
 299 }