kernel/drivers/clk/hisilicon/clk-hi6220-stub.c

   1 /*
   2  * Hi6220 stub clock driver
   3  *
   4  * Copyright (c) 2015 Hisilicon Limited.
   5  * Copyright (c) 2015 Linaro Limited.
   6  *
   7  * Author: Leo Yan <leo.yan@linaro.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  */
  14
  15 #include <linux/clk-provider.h>
  16 #include <linux/err.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mfd/syscon.h>
  19 #include <linux/mailbox_client.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/regmap.h>
  23
  24 /* Stub clocks id */
  25 #define HI6220_STUB_ACPU0               0
  26 #define HI6220_STUB_ACPU1               1
  27 #define HI6220_STUB_GPU                 2
  28 #define HI6220_STUB_DDR                 5
  29
  30 /* Mailbox message */
  31 #define HI6220_MBOX_MSG_LEN             8
  32
  33 #define HI6220_MBOX_FREQ                0xA
  34 #define HI6220_MBOX_CMD_SET             0x3
  35 #define HI6220_MBOX_OBJ_AP              0x0
  36
  37 /* CPU dynamic frequency scaling */
  38 #define ACPU_DFS_FREQ_MAX               0x1724
  39 #define ACPU_DFS_CUR_FREQ               0x17CC
  40 #define ACPU_DFS_FLAG                   0x1B30
  41 #define ACPU_DFS_FREQ_REQ               0x1B34
  42 #define ACPU_DFS_FREQ_LMT               0x1B38
  43 #define ACPU_DFS_LOCK_FLAG              0xAEAEAEAE
  44
  45 #define to_stub_clk(hw) container_of(hw, struct hi6220_stub_clk, hw)
  46
  47 struct hi6220_stub_clk {
  48         u32 id;
  49
  50         struct device *dev;
  51         struct clk_hw hw;
  52
  53         struct regmap *dfs_map;
  54         struct mbox_client cl;
  55         struct mbox_chan *mbox;
  56 };
  57
  58 struct hi6220_mbox_msg {
  59         unsigned char type;
  60         unsigned char cmd;
  61         unsigned char obj;
  62         unsigned char src;
  63         unsigned char para[4];
  64 };
  65
  66 union hi6220_mbox_data {
  67         unsigned int data[HI6220_MBOX_MSG_LEN];
  68         struct hi6220_mbox_msg msg;
  69 };
  70
  71 static unsigned int hi6220_acpu_get_freq(struct hi6220_stub_clk *stub_clk)
  72 {
  73         unsigned int freq;
  74
  75         regmap_read(stub_clk->dfs_map, ACPU_DFS_CUR_FREQ, &freq);
  76         return freq;
  77 }
  78
  79 static int hi6220_acpu_set_freq(struct hi6220_stub_clk *stub_clk,
  80                                 unsigned int freq)
  81 {
  82         union hi6220_mbox_data data;
  83
  84         /* set the frequency in sram */
  85         regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, freq);
  86
  87         /* compound mailbox message */
  88         data.msg.type = HI6220_MBOX_FREQ;
  89         data.msg.cmd  = HI6220_MBOX_CMD_SET;
  90         data.msg.obj  = HI6220_MBOX_OBJ_AP;
  91         data.msg.src  = HI6220_MBOX_OBJ_AP;
  92
  93         mbox_send_message(stub_clk->mbox, &data);
  94         return 0;
  95 }
  96
  97 static int hi6220_acpu_round_freq(struct hi6220_stub_clk *stub_clk,
  98                                   unsigned int freq)
  99 {
 100         unsigned int limit_flag, limit_freq = UINT_MAX;
 101         unsigned int max_freq;
 102
 103         /* check the constrained frequency */
 104         regmap_read(stub_clk->dfs_map, ACPU_DFS_FLAG, &limit_flag);
 105         if (limit_flag == ACPU_DFS_LOCK_FLAG)
 106                 regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, &limit_freq);
 107
 108         /* check the supported maximum frequency */
 109         regmap_read(stub_clk->dfs_map, ACPU_DFS_FREQ_MAX, &max_freq);
 110
 111         /* calculate the real maximum frequency */
 112         max_freq = min(max_freq, limit_freq);
 113
 114         if (WARN_ON(freq > max_freq))
 115                 freq = max_freq;
 116
 117         return freq;
 118 }
 119
 120 static unsigned long hi6220_stub_clk_recalc_rate(struct clk_hw *hw,
 121                 unsigned long parent_rate)
 122 {
 123         u32 rate = 0;
 124         struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
 125
 126         switch (stub_clk->id) {
 127         case HI6220_STUB_ACPU0:
 128                 rate = hi6220_acpu_get_freq(stub_clk);
 129
 130                 /* convert from kHz to Hz */
 131                 rate *= 1000;
 132                 break;
 133
 134         default:
 135                 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
 136                         __func__, stub_clk->id);
 137                 break;
 138         }
 139
 140         return rate;
 141 }
 142
 143 static int hi6220_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 144                 unsigned long parent_rate)
 145 {
 146         struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
 147         unsigned long new_rate = rate / 1000;  /* kHz */
 148         int ret = 0;
 149
 150         switch (stub_clk->id) {
 151         case HI6220_STUB_ACPU0:
 152                 ret = hi6220_acpu_set_freq(stub_clk, new_rate);
 153                 if (ret < 0)
 154                         return ret;
 155
 156                 break;
 157
 158         default:
 159                 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
 160                         __func__, stub_clk->id);
 161                 break;
 162         }
 163
 164         pr_debug("%s: set rate=%ldkHz\n", __func__, new_rate);
 165         return ret;
 166 }
 167
 168 static long hi6220_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 169                 unsigned long *parent_rate)
 170 {
 171         struct hi6220_stub_clk *stub_clk = to_stub_clk(hw);
 172         unsigned long new_rate = rate / 1000;  /* kHz */
 173
 174         switch (stub_clk->id) {
 175         case HI6220_STUB_ACPU0:
 176                 new_rate = hi6220_acpu_round_freq(stub_clk, new_rate);
 177
 178                 /* convert from kHz to Hz */
 179                 new_rate *= 1000;
 180                 break;
 181
 182         default:
 183                 dev_err(stub_clk->dev, "%s: un-supported clock id %d\n",
 184                         __func__, stub_clk->id);
 185                 break;
 186         }
 187
 188         return new_rate;
 189 }
 190
 191 static const struct clk_ops hi6220_stub_clk_ops = {
 192         .recalc_rate    = hi6220_stub_clk_recalc_rate,
 193         .round_rate     = hi6220_stub_clk_round_rate,
 194         .set_rate       = hi6220_stub_clk_set_rate,
 195 };
 196
 197 static int hi6220_stub_clk_probe(struct platform_device *pdev)
 198 {
 199         struct device *dev = &pdev->dev;
 200         struct clk_init_data init;
 201         struct hi6220_stub_clk *stub_clk;
 202         struct clk *clk;
 203         struct device_node *np = pdev->dev.of_node;
 204         int ret;
 205
 206         stub_clk = devm_kzalloc(dev, sizeof(*stub_clk), GFP_KERNEL);
 207         if (!stub_clk)
 208                 return -ENOMEM;
 209
 210         stub_clk->dfs_map = syscon_regmap_lookup_by_phandle(np,
 211                                 "hisilicon,hi6220-clk-sram");
 212         if (IS_ERR(stub_clk->dfs_map)) {
 213                 dev_err(dev, "failed to get sram regmap\n");
 214                 return PTR_ERR(stub_clk->dfs_map);
 215         }
 216
 217         stub_clk->hw.init = &init;
 218         stub_clk->dev = dev;
 219         stub_clk->id = HI6220_STUB_ACPU0;
 220
 221         /* Use mailbox client with blocking mode */
 222         stub_clk->cl.dev = dev;
 223         stub_clk->cl.tx_done = NULL;
 224         stub_clk->cl.tx_block = true;
 225         stub_clk->cl.tx_tout = 500;
 226         stub_clk->cl.knows_txdone = false;
 227
 228         /* Allocate mailbox channel */
 229         stub_clk->mbox = mbox_request_channel(&stub_clk->cl, 0);
 230         if (IS_ERR(stub_clk->mbox)) {
 231                 dev_err(dev, "failed get mailbox channel\n");
 232                 return PTR_ERR(stub_clk->mbox);
 233         }
 234
 235         init.name = "acpu0";
 236         init.ops = &hi6220_stub_clk_ops;
 237         init.num_parents = 0;
 238         init.flags = CLK_IS_ROOT;
 239
 240         clk = devm_clk_register(dev, &stub_clk->hw);
 241         if (IS_ERR(clk))
 242                 return PTR_ERR(clk);
 243
 244         ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
 245         if (ret) {
 246                 dev_err(dev, "failed to register OF clock provider\n");
 247                 return ret;
 248         }
 249
 250         /* initialize buffer to zero */
 251         regmap_write(stub_clk->dfs_map, ACPU_DFS_FLAG, 0x0);
 252         regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_REQ, 0x0);
 253         regmap_write(stub_clk->dfs_map, ACPU_DFS_FREQ_LMT, 0x0);
 254
 255         dev_dbg(dev, "Registered clock '%s'\n", init.name);
 256         return 0;
 257 }
 258
 259 static const struct of_device_id hi6220_stub_clk_of_match[] = {
 260         { .compatible = "hisilicon,hi6220-stub-clk", },
 261         {}
 262 };
 263
 264 static struct platform_driver hi6220_stub_clk_driver = {
 265         .driver = {
 266                 .name = "hi6220-stub-clk",
 267                 .of_match_table = hi6220_stub_clk_of_match,
 268         },
 269         .probe = hi6220_stub_clk_probe,
 270 };
 271
 272 static int __init hi6220_stub_clk_init(void)
 273 {
 274         return platform_driver_register(&hi6220_stub_clk_driver);
 275 }
 276 subsys_initcall(hi6220_stub_clk_init);