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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Hisilicon clock driver
   4  *
   5  * Copyright (c) 2013-2017 Hisilicon Limited.
   6  * Copyright (c) 2017 Linaro Limited.
   7  *
   8  * Author: Kai Zhao <zhaokai1@hisilicon.com>
   9  *          Tao Wang <kevin.wangtao@hisilicon.com>
  10  *          Leo Yan <leo.yan@linaro.org>
  11  */
  12
  13 #include <linux/clk-provider.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/io.h>
  18 #include <linux/mailbox_client.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/platform_device.h>
  22 #include <dt-bindings/clock/hi3660-clock.h>
  23
  24 #define HI3660_STUB_CLOCK_DATA          (0x70)
  25 #define MHZ                             (1000 * 1000)
  26
  27 #define DEFINE_CLK_STUB(_id, _cmd, _name)                       \
  28         {                                                       \
  29                 .id = (_id),                                    \
  30                 .cmd = (_cmd),                                  \
  31                 .hw.init = &(struct clk_init_data) {            \
  32                         .name = #_name,                         \
  33                         .ops = &hi3660_stub_clk_ops,            \
  34                         .num_parents = 0,                       \
  35                         .flags = CLK_GET_RATE_NOCACHE,          \
  36                 },                                              \
  37         },
  38
  39 #define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
  40
  41 struct hi3660_stub_clk_chan {
  42         struct mbox_client cl;
  43         struct mbox_chan *mbox;
  44 };
  45
  46 struct hi3660_stub_clk {
  47         unsigned int id;
  48         struct clk_hw hw;
  49         unsigned int cmd;
  50         unsigned int msg[8];
  51         unsigned int rate;
  52 };
  53
  54 static void __iomem *freq_reg;
  55 static struct hi3660_stub_clk_chan stub_clk_chan;
  56
  57 static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
  58                                                  unsigned long parent_rate)
  59 {
  60         struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  61
  62         /*
  63          * LPM3 writes back the CPU frequency in shared SRAM so read
  64          * back the frequency.
  65          */
  66         stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
  67         return stub_clk->rate;
  68 }
  69
  70 static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
  71                                        unsigned long *prate)
  72 {
  73         /*
  74          * LPM3 handles rate rounding so just return whatever
  75          * rate is requested.
  76          */
  77         return rate;
  78 }
  79
  80 static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
  81                                     unsigned long parent_rate)
  82 {
  83         struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  84
  85         stub_clk->msg[0] = stub_clk->cmd;
  86         stub_clk->msg[1] = rate / MHZ;
  87
  88         dev_dbg(stub_clk_chan.cl.dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
  89                 stub_clk->msg[0], stub_clk->msg[1]);
  90
  91         mbox_send_message(stub_clk_chan.mbox, stub_clk->msg);
  92         mbox_client_txdone(stub_clk_chan.mbox, 0);
  93
  94         stub_clk->rate = rate;
  95         return 0;
  96 }
  97
  98 static const struct clk_ops hi3660_stub_clk_ops = {
  99         .recalc_rate    = hi3660_stub_clk_recalc_rate,
 100         .round_rate     = hi3660_stub_clk_round_rate,
 101         .set_rate       = hi3660_stub_clk_set_rate,
 102 };
 103
 104 static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
 105         DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
 106         DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
 107         DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
 108         DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
 109 };
 110
 111 static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
 112                                              void *data)
 113 {
 114         unsigned int idx = clkspec->args[0];
 115
 116         if (idx >= HI3660_CLK_STUB_NUM) {
 117                 pr_err("%s: invalid index %u\n", __func__, idx);
 118                 return ERR_PTR(-EINVAL);
 119         }
 120
 121         return &hi3660_stub_clks[idx].hw;
 122 }
 123
 124 static int hi3660_stub_clk_probe(struct platform_device *pdev)
 125 {
 126         struct device *dev = &pdev->dev;
 127         struct resource *res;
 128         unsigned int i;
 129         int ret;
 130
 131         /* Use mailbox client without blocking */
 132         stub_clk_chan.cl.dev = dev;
 133         stub_clk_chan.cl.tx_done = NULL;
 134         stub_clk_chan.cl.tx_block = false;
 135         stub_clk_chan.cl.knows_txdone = false;
 136
 137         /* Allocate mailbox channel */
 138         stub_clk_chan.mbox = mbox_request_channel(&stub_clk_chan.cl, 0);
 139         if (IS_ERR(stub_clk_chan.mbox))
 140                 return PTR_ERR(stub_clk_chan.mbox);
 141
 142         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 143         if (!res)
 144                 return -EINVAL;
 145         freq_reg = devm_ioremap(dev, res->start, resource_size(res));
 146         if (!freq_reg)
 147                 return -ENOMEM;
 148
 149         freq_reg += HI3660_STUB_CLOCK_DATA;
 150
 151         for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
 152                 ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
 153                 if (ret)
 154                         return ret;
 155         }
 156
 157         return devm_of_clk_add_hw_provider(&pdev->dev, hi3660_stub_clk_hw_get,
 158                                            hi3660_stub_clks);
 159 }
 160
 161 static const struct of_device_id hi3660_stub_clk_of_match[] = {
 162         { .compatible = "hisilicon,hi3660-stub-clk", },
 163         {}
 164 };
 165
 166 static struct platform_driver hi3660_stub_clk_driver = {
 167         .probe  = hi3660_stub_clk_probe,
 168         .driver = {
 169                 .name = "hi3660-stub-clk",
 170                 .of_match_table = hi3660_stub_clk_of_match,
 171         },
 172 };
 173
 174 static int __init hi3660_stub_clk_init(void)
 175 {
 176         return platform_driver_register(&hi3660_stub_clk_driver);
 177 }
 178 subsys_initcall(hi3660_stub_clk_init);