drivers/clk/clk-highbank.c

   1 /*
   2  * Copyright 2011-2012 Calxeda, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19 #include <linux/err.h>
  20 #include <linux/clk-provider.h>
  21 #include <linux/io.h>
  22 #include <linux/of.h>
  23 #include <linux/of_address.h>
  24
  25 #define HB_PLL_LOCK_500         0x20000000
  26 #define HB_PLL_LOCK             0x10000000
  27 #define HB_PLL_DIVF_SHIFT       20
  28 #define HB_PLL_DIVF_MASK        0x0ff00000
  29 #define HB_PLL_DIVQ_SHIFT       16
  30 #define HB_PLL_DIVQ_MASK        0x00070000
  31 #define HB_PLL_DIVR_SHIFT       8
  32 #define HB_PLL_DIVR_MASK        0x00001f00
  33 #define HB_PLL_RANGE_SHIFT      4
  34 #define HB_PLL_RANGE_MASK       0x00000070
  35 #define HB_PLL_BYPASS           0x00000008
  36 #define HB_PLL_RESET            0x00000004
  37 #define HB_PLL_EXT_BYPASS       0x00000002
  38 #define HB_PLL_EXT_ENA          0x00000001
  39
  40 #define HB_PLL_VCO_MIN_FREQ     2133000000
  41 #define HB_PLL_MAX_FREQ         HB_PLL_VCO_MIN_FREQ
  42 #define HB_PLL_MIN_FREQ         (HB_PLL_VCO_MIN_FREQ / 64)
  43
  44 #define HB_A9_BCLK_DIV_MASK     0x00000006
  45 #define HB_A9_BCLK_DIV_SHIFT    1
  46 #define HB_A9_PCLK_DIV          0x00000001
  47
  48 struct hb_clk {
  49         struct clk_hw   hw;
  50         void __iomem    *reg;
  51         char *parent_name;
  52 };
  53 #define to_hb_clk(p) container_of(p, struct hb_clk, hw)
  54
  55 static int clk_pll_prepare(struct clk_hw *hwclk)
  56         {
  57         struct hb_clk *hbclk = to_hb_clk(hwclk);
  58         u32 reg;
  59
  60         reg = readl(hbclk->reg);
  61         reg &= ~HB_PLL_RESET;
  62         writel(reg, hbclk->reg);
  63
  64         while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
  65                 ;
  66         while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
  67                 ;
  68
  69         return 0;
  70 }
  71
  72 static void clk_pll_unprepare(struct clk_hw *hwclk)
  73 {
  74         struct hb_clk *hbclk = to_hb_clk(hwclk);
  75         u32 reg;
  76
  77         reg = readl(hbclk->reg);
  78         reg |= HB_PLL_RESET;
  79         writel(reg, hbclk->reg);
  80 }
  81
  82 static int clk_pll_enable(struct clk_hw *hwclk)
  83 {
  84         struct hb_clk *hbclk = to_hb_clk(hwclk);
  85         u32 reg;
  86
  87         reg = readl(hbclk->reg);
  88         reg |= HB_PLL_EXT_ENA;
  89         writel(reg, hbclk->reg);
  90
  91         return 0;
  92 }
  93
  94 static void clk_pll_disable(struct clk_hw *hwclk)
  95 {
  96         struct hb_clk *hbclk = to_hb_clk(hwclk);
  97         u32 reg;
  98
  99         reg = readl(hbclk->reg);
 100         reg &= ~HB_PLL_EXT_ENA;
 101         writel(reg, hbclk->reg);
 102 }
 103
 104 static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
 105                                          unsigned long parent_rate)
 106 {
 107         struct hb_clk *hbclk = to_hb_clk(hwclk);
 108         unsigned long divf, divq, vco_freq, reg;
 109
 110         reg = readl(hbclk->reg);
 111         if (reg & HB_PLL_EXT_BYPASS)
 112                 return parent_rate;
 113
 114         divf = (reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT;
 115         divq = (reg & HB_PLL_DIVQ_MASK) >> HB_PLL_DIVQ_SHIFT;
 116         vco_freq = parent_rate * (divf + 1);
 117
 118         return vco_freq / (1 << divq);
 119 }
 120
 121 static void clk_pll_calc(unsigned long rate, unsigned long ref_freq,
 122                         u32 *pdivq, u32 *pdivf)
 123 {
 124         u32 divq, divf;
 125         unsigned long vco_freq;
 126
 127         if (rate < HB_PLL_MIN_FREQ)
 128                 rate = HB_PLL_MIN_FREQ;
 129         if (rate > HB_PLL_MAX_FREQ)
 130                 rate = HB_PLL_MAX_FREQ;
 131
 132         for (divq = 1; divq <= 6; divq++) {
 133                 if ((rate * (1 << divq)) >= HB_PLL_VCO_MIN_FREQ)
 134                         break;
 135         }
 136
 137         vco_freq = rate * (1 << divq);
 138         divf = (vco_freq + (ref_freq / 2)) / ref_freq;
 139         divf--;
 140
 141         *pdivq = divq;
 142         *pdivf = divf;
 143 }
 144
 145 static long clk_pll_round_rate(struct clk_hw *hwclk, unsigned long rate,
 146                                unsigned long *parent_rate)
 147 {
 148         u32 divq, divf;
 149         unsigned long ref_freq = *parent_rate;
 150
 151         clk_pll_calc(rate, ref_freq, &divq, &divf);
 152
 153         return (ref_freq * (divf + 1)) / (1 << divq);
 154 }
 155
 156 static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
 157                             unsigned long parent_rate)
 158 {
 159         struct hb_clk *hbclk = to_hb_clk(hwclk);
 160         u32 divq, divf;
 161         u32 reg;
 162
 163         clk_pll_calc(rate, parent_rate, &divq, &divf);
 164
 165         reg = readl(hbclk->reg);
 166         if (divf != ((reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT)) {
 167                 /* Need to re-lock PLL, so put it into bypass mode */
 168                 reg |= HB_PLL_EXT_BYPASS;
 169                 writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 170
 171                 writel(reg | HB_PLL_RESET, hbclk->reg);
 172                 reg &= ~(HB_PLL_DIVF_MASK | HB_PLL_DIVQ_MASK);
 173                 reg |= (divf << HB_PLL_DIVF_SHIFT) | (divq << HB_PLL_DIVQ_SHIFT);
 174                 writel(reg | HB_PLL_RESET, hbclk->reg);
 175                 writel(reg, hbclk->reg);
 176
 177                 while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
 178                         ;
 179                 while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
 180                         ;
 181                 reg |= HB_PLL_EXT_ENA;
 182                 reg &= ~HB_PLL_EXT_BYPASS;
 183         } else {
 184                 writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 185                 reg &= ~HB_PLL_DIVQ_MASK;
 186                 reg |= divq << HB_PLL_DIVQ_SHIFT;
 187                 writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
 188         }
 189         writel(reg, hbclk->reg);
 190
 191         return 0;
 192 }
 193
 194 static const struct clk_ops clk_pll_ops = {
 195         .prepare = clk_pll_prepare,
 196         .unprepare = clk_pll_unprepare,
 197         .enable = clk_pll_enable,
 198         .disable = clk_pll_disable,
 199         .recalc_rate = clk_pll_recalc_rate,
 200         .round_rate = clk_pll_round_rate,
 201         .set_rate = clk_pll_set_rate,
 202 };
 203
 204 static unsigned long clk_cpu_periphclk_recalc_rate(struct clk_hw *hwclk,
 205                                                    unsigned long parent_rate)
 206 {
 207         struct hb_clk *hbclk = to_hb_clk(hwclk);
 208         u32 div = (readl(hbclk->reg) & HB_A9_PCLK_DIV) ? 8 : 4;
 209         return parent_rate / div;
 210 }
 211
 212 static const struct clk_ops a9periphclk_ops = {
 213         .recalc_rate = clk_cpu_periphclk_recalc_rate,
 214 };
 215
 216 static unsigned long clk_cpu_a9bclk_recalc_rate(struct clk_hw *hwclk,
 217                                                 unsigned long parent_rate)
 218 {
 219         struct hb_clk *hbclk = to_hb_clk(hwclk);
 220         u32 div = (readl(hbclk->reg) & HB_A9_BCLK_DIV_MASK) >> HB_A9_BCLK_DIV_SHIFT;
 221
 222         return parent_rate / (div + 2);
 223 }
 224
 225 static const struct clk_ops a9bclk_ops = {
 226         .recalc_rate = clk_cpu_a9bclk_recalc_rate,
 227 };
 228
 229 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
 230                                              unsigned long parent_rate)
 231 {
 232         struct hb_clk *hbclk = to_hb_clk(hwclk);
 233         u32 div;
 234
 235         div = readl(hbclk->reg) & 0x1f;
 236         div++;
 237         div *= 2;
 238
 239         return parent_rate / div;
 240 }
 241
 242 static long clk_periclk_round_rate(struct clk_hw *hwclk, unsigned long rate,
 243                                    unsigned long *parent_rate)
 244 {
 245         u32 div;
 246
 247         div = *parent_rate / rate;
 248         div++;
 249         div &= ~0x1;
 250
 251         return *parent_rate / div;
 252 }
 253
 254 static int clk_periclk_set_rate(struct clk_hw *hwclk, unsigned long rate,
 255                                 unsigned long parent_rate)
 256 {
 257         struct hb_clk *hbclk = to_hb_clk(hwclk);
 258         u32 div;
 259
 260         div = parent_rate / rate;
 261         if (div & 0x1)
 262                 return -EINVAL;
 263
 264         writel(div >> 1, hbclk->reg);
 265         return 0;
 266 }
 267
 268 static const struct clk_ops periclk_ops = {
 269         .recalc_rate = clk_periclk_recalc_rate,
 270         .round_rate = clk_periclk_round_rate,
 271         .set_rate = clk_periclk_set_rate,
 272 };
 273
 274 static __init struct clk *hb_clk_init(struct device_node *node, const struct clk_ops *ops)
 275 {
 276         u32 reg;
 277         struct clk *clk;
 278         struct hb_clk *hb_clk;
 279         const char *clk_name = node->name;
 280         const char *parent_name;
 281         struct clk_init_data init;
 282         struct device_node *srnp;
 283         int rc;
 284
 285         rc = of_property_read_u32(node, "reg", &reg);
 286         if (WARN_ON(rc))
 287                 return NULL;
 288
 289         hb_clk = kzalloc(sizeof(*hb_clk), GFP_KERNEL);
 290         if (WARN_ON(!hb_clk))
 291                 return NULL;
 292
 293         /* Map system registers */
 294         srnp = of_find_compatible_node(NULL, NULL, "calxeda,hb-sregs");
 295         hb_clk->reg = of_iomap(srnp, 0);
 296         BUG_ON(!hb_clk->reg);
 297         hb_clk->reg += reg;
 298
 299         of_property_read_string(node, "clock-output-names", &clk_name);
 300
 301         init.name = clk_name;
 302         init.ops = ops;
 303         init.flags = 0;
 304         parent_name = of_clk_get_parent_name(node, 0);
 305         init.parent_names = &parent_name;
 306         init.num_parents = 1;
 307
 308         hb_clk->hw.init = &init;
 309
 310         clk = clk_register(NULL, &hb_clk->hw);
 311         if (WARN_ON(IS_ERR(clk))) {
 312                 kfree(hb_clk);
 313                 return NULL;
 314         }
 315         rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 316         return clk;
 317 }
 318
 319 static void __init hb_pll_init(struct device_node *node)
 320 {
 321         hb_clk_init(node, &clk_pll_ops);
 322 }
 323 CLK_OF_DECLARE(hb_pll, "calxeda,hb-pll-clock", hb_pll_init);
 324
 325 static void __init hb_a9periph_init(struct device_node *node)
 326 {
 327         hb_clk_init(node, &a9periphclk_ops);
 328 }
 329 CLK_OF_DECLARE(hb_a9periph, "calxeda,hb-a9periph-clock", hb_a9periph_init);
 330
 331 static void __init hb_a9bus_init(struct device_node *node)
 332 {
 333         struct clk *clk = hb_clk_init(node, &a9bclk_ops);
 334         clk_prepare_enable(clk);
 335 }
 336 CLK_OF_DECLARE(hb_a9bus, "calxeda,hb-a9bus-clock", hb_a9bus_init);
 337
 338 static void __init hb_emmc_init(struct device_node *node)
 339 {
 340         hb_clk_init(node, &periclk_ops);
 341 }
 342 CLK_OF_DECLARE(hb_emmc, "calxeda,hb-emmc-clock", hb_emmc_init);