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); 188