drivers/clk/hisilicon/clk-hi3660-stub.c

   1 /*
   2  * Hisilicon clock driver
   3  *
   4  * Copyright (c) 2013-2017 Hisilicon Limited.
   5  * Copyright (c) 2017 Linaro Limited.
   6  *
   7  * Author: Kai Zhao <zhaokai1@hisilicon.com>
   8  *          Tao Wang <kevin.wangtao@hisilicon.com>
   9  *          Leo Yan <leo.yan@linaro.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  */
  22
  23 #include <linux/clk-provider.h>
  24 #include <linux/device.h>
  25 #include <linux/err.h>
  26 #include <linux/init.h>
  27 #include <linux/mailbox_client.h>
  28 #include <linux/module.h>
  29 #include <linux/of.h>
  30 #include <linux/platform_device.h>
  31 #include <dt-bindings/clock/hi3660-clock.h>
  32
  33 #define HI3660_STUB_CLOCK_DATA          (0x70)
  34 #define MHZ                             (1000 * 1000)
  35
  36 #define DEFINE_CLK_STUB(_id, _cmd, _name)                       \
  37         {                                                       \
  38                 .id = (_id),                                    \
  39                 .cmd = (_cmd),                                  \
  40                 .hw.init = &(struct clk_init_data) {            \
  41                         .name = #_name,                         \
  42                         .ops = &hi3660_stub_clk_ops,            \
  43                         .num_parents = 0,                       \
  44                         .flags = CLK_GET_RATE_NOCACHE,          \
  45                 },                                              \
  46         },
  47
  48 #define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
  49
  50 struct hi3660_stub_clk_chan {
  51         struct mbox_client cl;
  52         struct mbox_chan *mbox;
  53 };
  54
  55 struct hi3660_stub_clk {
  56         unsigned int id;
  57         struct clk_hw hw;
  58         unsigned int cmd;
  59         unsigned int msg[8];
  60         unsigned int rate;
  61 };
  62
  63 static void __iomem *freq_reg;
  64 static struct hi3660_stub_clk_chan stub_clk_chan;
  65
  66 static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
  67                                                  unsigned long parent_rate)
  68 {
  69         struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  70
  71         /*
  72          * LPM3 writes back the CPU frequency in shared SRAM so read
  73          * back the frequency.
  74          */
  75         stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
  76         return stub_clk->rate;
  77 }
  78
  79 static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
  80                                        unsigned long *prate)
  81 {
  82         /*
  83          * LPM3 handles rate rounding so just return whatever
  84          * rate is requested.
  85          */
  86         return rate;
  87 }
  88
  89 static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
  90                                     unsigned long parent_rate)
  91 {
  92         struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  93
  94         stub_clk->msg[0] = stub_clk->cmd;
  95         stub_clk->msg[1] = rate / MHZ;
  96
  97         dev_dbg(stub_clk_chan.cl.dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
  98                 stub_clk->msg[0], stub_clk->msg[1]);
  99
 100         mbox_send_message(stub_clk_chan.mbox, stub_clk->msg);
 101         mbox_client_txdone(stub_clk_chan.mbox, 0);
 102
 103         stub_clk->rate = rate;
 104         return 0;
 105 }
 106
 107 static const struct clk_ops hi3660_stub_clk_ops = {
 108         .recalc_rate    = hi3660_stub_clk_recalc_rate,
 109         .round_rate     = hi3660_stub_clk_round_rate,
 110         .set_rate       = hi3660_stub_clk_set_rate,
 111 };
 112
 113 static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
 114         DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
 115         DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
 116         DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
 117         DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
 118 };
 119
 120 static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
 121                                              void *data)
 122 {
 123         unsigned int idx = clkspec->args[0];
 124
 125         if (idx >= HI3660_CLK_STUB_NUM) {
 126                 pr_err("%s: invalid index %u\n", __func__, idx);
 127                 return ERR_PTR(-EINVAL);
 128         }
 129
 130         return &hi3660_stub_clks[idx].hw;
 131 }
 132
 133 static int hi3660_stub_clk_probe(struct platform_device *pdev)
 134 {
 135         struct device *dev = &pdev->dev;
 136         struct resource *res;
 137         unsigned int i;
 138         int ret;
 139
 140         /* Use mailbox client without blocking */
 141         stub_clk_chan.cl.dev = dev;
 142         stub_clk_chan.cl.tx_done = NULL;
 143         stub_clk_chan.cl.tx_block = false;
 144         stub_clk_chan.cl.knows_txdone = false;
 145
 146         /* Allocate mailbox channel */
 147         stub_clk_chan.mbox = mbox_request_channel(&stub_clk_chan.cl, 0);
 148         if (IS_ERR(stub_clk_chan.mbox))
 149                 return PTR_ERR(stub_clk_chan.mbox);
 150
 151         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 152         if (!res)
 153                 return -EINVAL;
 154         freq_reg = devm_ioremap(dev, res->start, resource_size(res));
 155         if (!freq_reg)
 156                 return -ENOMEM;
 157
 158         freq_reg += HI3660_STUB_CLOCK_DATA;
 159
 160         for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
 161                 ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
 162                 if (ret)
 163                         return ret;
 164         }
 165
 166         return devm_of_clk_add_hw_provider(&pdev->dev, hi3660_stub_clk_hw_get,
 167                                            hi3660_stub_clks);
 168 }
 169
 170 static const struct of_device_id hi3660_stub_clk_of_match[] = {
 171         { .compatible = "hisilicon,hi3660-stub-clk", },
 172         {}
 173 };
 174
 175 static struct platform_driver hi3660_stub_clk_driver = {
 176         .probe  = hi3660_stub_clk_probe,
 177         .driver = {
 178                 .name = "hi3660-stub-clk",
 179                 .of_match_table = hi3660_stub_clk_of_match,
 180         },
 181 };
 182
 183 static int __init hi3660_stub_clk_init(void)
 184 {
 185         return platform_driver_register(&hi3660_stub_clk_driver);
 186 }
 187 subsys_initcall(hi3660_stub_clk_init);