1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/sh/kernel/cpu/sh4/clock-sh4-202.c 4 * 5 * Additional SH4-202 support for the clock framework 6 * 7 * Copyright (C) 2005 Paul Mundt 8 */ 9 #include <linux/init.h> 10 #include <linux/kernel.h> 11 #include <linux/err.h> 12 #include <linux/io.h> 13 #include <linux/clkdev.h> 14 #include <asm/clock.h> 15 #include <asm/freq.h> 16 17 #define CPG2_FRQCR3 0xfe0a0018 18 19 static int frqcr3_divisors[] = { 1, 2, 3, 4, 6, 8, 16 }; 20 static int frqcr3_values[] = { 0, 1, 2, 3, 4, 5, 6 }; 21 22 static unsigned long emi_clk_recalc(struct clk *clk) 23 { 24 int idx = __raw_readl(CPG2_FRQCR3) & 0x0007; 25 return clk->parent->rate / frqcr3_divisors[idx]; 26 } 27 28 static inline int frqcr3_lookup(struct clk *clk, unsigned long rate) 29 { 30 int divisor = clk->parent->rate / rate; 31 int i; 32 33 for (i = 0; i < ARRAY_SIZE(frqcr3_divisors); i++) 34 if (frqcr3_divisors[i] == divisor) 35 return frqcr3_values[i]; 36 37 /* Safe fallback */ 38 return 5; 39 } 40 41 static struct sh_clk_ops sh4202_emi_clk_ops = { 42 .recalc = emi_clk_recalc, 43 }; 44 45 static struct clk sh4202_emi_clk = { 46 .flags = CLK_ENABLE_ON_INIT, 47 .ops = &sh4202_emi_clk_ops, 48 }; 49 50 static unsigned long femi_clk_recalc(struct clk *clk) 51 { 52 int idx = (__raw_readl(CPG2_FRQCR3) >> 3) & 0x0007; 53 return clk->parent->rate / frqcr3_divisors[idx]; 54 } 55 56 static struct sh_clk_ops sh4202_femi_clk_ops = { 57 .recalc = femi_clk_recalc, 58 }; 59 60 static struct clk sh4202_femi_clk = { 61 .flags = CLK_ENABLE_ON_INIT, 62 .ops = &sh4202_femi_clk_ops, 63 }; 64 65 static void shoc_clk_init(struct clk *clk) 66 { 67 int i; 68 69 /* 70 * For some reason, the shoc_clk seems to be set to some really 71 * insane value at boot (values outside of the allowable frequency 72 * range for instance). We deal with this by scaling it back down 73 * to something sensible just in case. 74 * 75 * Start scaling from the high end down until we find something 76 * that passes rate verification.. 77 */ 78 for (i = 0; i < ARRAY_SIZE(frqcr3_divisors); i++) { 79 int divisor = frqcr3_divisors[i]; 80 81 if (clk->ops->set_rate(clk, clk->parent->rate / divisor) == 0) 82 break; 83 } 84 85 WARN_ON(i == ARRAY_SIZE(frqcr3_divisors)); /* Undefined clock */ 86 } 87 88 static unsigned long shoc_clk_recalc(struct clk *clk) 89 { 90 int idx = (__raw_readl(CPG2_FRQCR3) >> 6) & 0x0007; 91 return clk->parent->rate / frqcr3_divisors[idx]; 92 } 93 94 static int shoc_clk_verify_rate(struct clk *clk, unsigned long rate) 95 { 96 struct clk *bclk = clk_get(NULL, "bus_clk"); 97 unsigned long bclk_rate = clk_get_rate(bclk); 98 99 clk_put(bclk); 100 101 if (rate > bclk_rate) 102 return 1; 103 if (rate > 66000000) 104 return 1; 105 106 return 0; 107 } 108 109 static int shoc_clk_set_rate(struct clk *clk, unsigned long rate) 110 { 111 unsigned long frqcr3; 112 unsigned int tmp; 113 114 /* Make sure we have something sensible to switch to */ 115 if (shoc_clk_verify_rate(clk, rate) != 0) 116 return -EINVAL; 117 118 tmp = frqcr3_lookup(clk, rate); 119 120 frqcr3 = __raw_readl(CPG2_FRQCR3); 121 frqcr3 &= ~(0x0007 << 6); 122 frqcr3 |= tmp << 6; 123 __raw_writel(frqcr3, CPG2_FRQCR3); 124 125 clk->rate = clk->parent->rate / frqcr3_divisors[tmp]; 126 127 return 0; 128 } 129 130 static struct sh_clk_ops sh4202_shoc_clk_ops = { 131 .init = shoc_clk_init, 132 .recalc = shoc_clk_recalc, 133 .set_rate = shoc_clk_set_rate, 134 }; 135 136 static struct clk sh4202_shoc_clk = { 137 .flags = CLK_ENABLE_ON_INIT, 138 .ops = &sh4202_shoc_clk_ops, 139 }; 140 141 static struct clk *sh4202_onchip_clocks[] = { 142 &sh4202_emi_clk, 143 &sh4202_femi_clk, 144 &sh4202_shoc_clk, 145 }; 146 147 static struct clk_lookup lookups[] = { 148 /* main clocks */ 149 CLKDEV_CON_ID("emi_clk", &sh4202_emi_clk), 150 CLKDEV_CON_ID("femi_clk", &sh4202_femi_clk), 151 CLKDEV_CON_ID("shoc_clk", &sh4202_shoc_clk), 152 }; 153 154 int __init arch_clk_init(void) 155 { 156 struct clk *clk; 157 int i, ret = 0; 158 159 cpg_clk_init(); 160 161 clk = clk_get(NULL, "master_clk"); 162 for (i = 0; i < ARRAY_SIZE(sh4202_onchip_clocks); i++) { 163 struct clk *clkp = sh4202_onchip_clocks[i]; 164 165 clkp->parent = clk; 166 ret |= clk_register(clkp); 167 } 168 169 clk_put(clk); 170 171 clkdev_add_table(lookups, ARRAY_SIZE(lookups)); 172 173 return ret; 174 } 175