linux/drivers/clk/hisilicon/clk-hi3660-stub.c
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   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
  41struct hi3660_stub_clk_chan {
  42        struct mbox_client cl;
  43        struct mbox_chan *mbox;
  44};
  45
  46struct 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
  54static void __iomem *freq_reg;
  55static struct hi3660_stub_clk_chan stub_clk_chan;
  56
  57static 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
  70static 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
  80static 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
  98static 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
 104static 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
 111static 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
 124static 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
 161static const struct of_device_id hi3660_stub_clk_of_match[] = {
 162        { .compatible = "hisilicon,hi3660-stub-clk", },
 163        {}
 164};
 165
 166static 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
 174static int __init hi3660_stub_clk_init(void)
 175{
 176        return platform_driver_register(&hi3660_stub_clk_driver);
 177}
 178subsys_initcall(hi3660_stub_clk_init);
 179