1 /* 2 * Marvell MVEBU CPU clock handling. 3 * 4 * Copyright (C) 2012 Marvell 5 * 6 * Gregory CLEMENT <gregory.clement@free-electrons.com> 7 * 8 * This file is licensed under the terms of the GNU General Public 9 * License version 2. This program is licensed "as is" without any 10 * warranty of any kind, whether express or implied. 11 */ 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/clk.h> 15 #include <linux/clk-provider.h> 16 #include <linux/of_address.h> 17 #include <linux/io.h> 18 #include <linux/of.h> 19 #include <linux/delay.h> 20 #include <linux/mvebu-pmsu.h> 21 #include <asm/smp_plat.h> 22 23 #define SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET 0x0 24 #define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL 0xff 25 #define SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT 8 26 #define SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET 0x8 27 #define SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT 16 28 #define SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET 0xC 29 #define SYS_CTRL_CLK_DIVIDER_MASK 0x3F 30 31 #define PMU_DFS_RATIO_SHIFT 16 32 #define PMU_DFS_RATIO_MASK 0x3F 33 34 #define MAX_CPU 4 35 struct cpu_clk { 36 struct clk_hw hw; 37 int cpu; 38 const char *clk_name; 39 const char *parent_name; 40 void __iomem *reg_base; 41 void __iomem *pmu_dfs; 42 }; 43 44 static struct clk **clks; 45 46 static struct clk_onecell_data clk_data; 47 48 #define to_cpu_clk(p) container_of(p, struct cpu_clk, hw) 49 50 static unsigned long clk_cpu_recalc_rate(struct clk_hw *hwclk, 51 unsigned long parent_rate) 52 { 53 struct cpu_clk *cpuclk = to_cpu_clk(hwclk); 54 u32 reg, div; 55 56 reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET); 57 div = (reg >> (cpuclk->cpu * 8)) & SYS_CTRL_CLK_DIVIDER_MASK; 58 return parent_rate / div; 59 } 60 61 static long clk_cpu_round_rate(struct clk_hw *hwclk, unsigned long rate, 62 unsigned long *parent_rate) 63 { 64 /* Valid ratio are 1:1, 1:2 and 1:3 */ 65 u32 div; 66 67 div = *parent_rate / rate; 68 if (div == 0) 69 div = 1; 70 else if (div > 3) 71 div = 3; 72 73 return *parent_rate / div; 74 } 75 76 static int clk_cpu_off_set_rate(struct clk_hw *hwclk, unsigned long rate, 77 unsigned long parent_rate) 78 79 { 80 struct cpu_clk *cpuclk = to_cpu_clk(hwclk); 81 u32 reg, div; 82 u32 reload_mask; 83 84 div = parent_rate / rate; 85 reg = (readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET) 86 & (~(SYS_CTRL_CLK_DIVIDER_MASK << (cpuclk->cpu * 8)))) 87 | (div << (cpuclk->cpu * 8)); 88 writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_VALUE_OFFSET); 89 /* Set clock divider reload smooth bit mask */ 90 reload_mask = 1 << (20 + cpuclk->cpu); 91 92 reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET) 93 | reload_mask; 94 writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); 95 96 /* Now trigger the clock update */ 97 reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET) 98 | 1 << 24; 99 writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); 100 101 /* Wait for clocks to settle down then clear reload request */ 102 udelay(1000); 103 reg &= ~(reload_mask | 1 << 24); 104 writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); 105 udelay(1000); 106 107 return 0; 108 } 109 110 static int clk_cpu_on_set_rate(struct clk_hw *hwclk, unsigned long rate, 111 unsigned long parent_rate) 112 { 113 u32 reg; 114 unsigned long fabric_div, target_div, cur_rate; 115 struct cpu_clk *cpuclk = to_cpu_clk(hwclk); 116 117 /* 118 * PMU DFS registers are not mapped, Device Tree does not 119 * describes them. We cannot change the frequency dynamically. 120 */ 121 if (!cpuclk->pmu_dfs) 122 return -ENODEV; 123 124 cur_rate = clk_hw_get_rate(hwclk); 125 126 reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL2_OFFSET); 127 fabric_div = (reg >> SYS_CTRL_CLK_DIVIDER_CTRL2_NBCLK_RATIO_SHIFT) & 128 SYS_CTRL_CLK_DIVIDER_MASK; 129 130 /* Frequency is going up */ 131 if (rate == 2 * cur_rate) 132 target_div = fabric_div / 2; 133 /* Frequency is going down */ 134 else 135 target_div = fabric_div; 136 137 if (target_div == 0) 138 target_div = 1; 139 140 reg = readl(cpuclk->pmu_dfs); 141 reg &= ~(PMU_DFS_RATIO_MASK << PMU_DFS_RATIO_SHIFT); 142 reg |= (target_div << PMU_DFS_RATIO_SHIFT); 143 writel(reg, cpuclk->pmu_dfs); 144 145 reg = readl(cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); 146 reg |= (SYS_CTRL_CLK_DIVIDER_CTRL_RESET_ALL << 147 SYS_CTRL_CLK_DIVIDER_CTRL_RESET_SHIFT); 148 writel(reg, cpuclk->reg_base + SYS_CTRL_CLK_DIVIDER_CTRL_OFFSET); 149 150 return mvebu_pmsu_dfs_request(cpuclk->cpu); 151 } 152 153 static int clk_cpu_set_rate(struct clk_hw *hwclk, unsigned long rate, 154 unsigned long parent_rate) 155 { 156 if (__clk_is_enabled(hwclk->clk)) 157 return clk_cpu_on_set_rate(hwclk, rate, parent_rate); 158 else 159 return clk_cpu_off_set_rate(hwclk, rate, parent_rate); 160 } 161 162 static const struct clk_ops cpu_ops = { 163 .recalc_rate = clk_cpu_recalc_rate, 164 .round_rate = clk_cpu_round_rate, 165 .set_rate = clk_cpu_set_rate, 166 }; 167 168 static void __init of_cpu_clk_setup(struct device_node *node) 169 { 170 struct cpu_clk *cpuclk; 171 void __iomem *clock_complex_base = of_iomap(node, 0); 172 void __iomem *pmu_dfs_base = of_iomap(node, 1); 173 int ncpus = 0; 174 struct device_node *dn; 175 176 if (clock_complex_base == NULL) { 177 pr_err("%s: clock-complex base register not set\n", 178 __func__); 179 return; 180 } 181 182 if (pmu_dfs_base == NULL) 183 pr_warn("%s: pmu-dfs base register not set, dynamic frequency scaling not available\n", 184 __func__); 185 186 for_each_node_by_type(dn, "cpu") 187 ncpus++; 188 189 cpuclk = kzalloc(ncpus * sizeof(*cpuclk), GFP_KERNEL); 190 if (WARN_ON(!cpuclk)) 191 goto cpuclk_out; 192 193 clks = kzalloc(ncpus * sizeof(*clks), GFP_KERNEL); 194 if (WARN_ON(!clks)) 195 goto clks_out; 196 197 for_each_node_by_type(dn, "cpu") { 198 struct clk_init_data init; 199 struct clk *clk; 200 char *clk_name = kzalloc(5, GFP_KERNEL); 201 int cpu, err; 202 203 if (WARN_ON(!clk_name)) 204 goto bail_out; 205 206 err = of_property_read_u32(dn, "reg", &cpu); 207 if (WARN_ON(err)) 208 goto bail_out; 209 210 sprintf(clk_name, "cpu%d", cpu); 211 212 cpuclk[cpu].parent_name = of_clk_get_parent_name(node, 0); 213 cpuclk[cpu].clk_name = clk_name; 214 cpuclk[cpu].cpu = cpu; 215 cpuclk[cpu].reg_base = clock_complex_base; 216 if (pmu_dfs_base) 217 cpuclk[cpu].pmu_dfs = pmu_dfs_base + 4 * cpu; 218 cpuclk[cpu].hw.init = &init; 219 220 init.name = cpuclk[cpu].clk_name; 221 init.ops = &cpu_ops; 222 init.flags = 0; 223 init.parent_names = &cpuclk[cpu].parent_name; 224 init.num_parents = 1; 225 226 clk = clk_register(NULL, &cpuclk[cpu].hw); 227 if (WARN_ON(IS_ERR(clk))) 228 goto bail_out; 229 clks[cpu] = clk; 230 } 231 clk_data.clk_num = MAX_CPU; 232 clk_data.clks = clks; 233 of_clk_add_provider(node, of_clk_src_onecell_get, &clk_data); 234 235 return; 236 bail_out: 237 kfree(clks); 238 while(ncpus--) 239 kfree(cpuclk[ncpus].clk_name); 240 clks_out: 241 kfree(cpuclk); 242 cpuclk_out: 243 iounmap(clock_complex_base); 244 } 245 246 CLK_OF_DECLARE(armada_xp_cpu_clock, "marvell,armada-xp-cpu-clock", 247 of_cpu_clk_setup); 248