1 /* $NetBSD: meson_clk_div.c,v 1.3 2019/02/25 19:30:17 jmcneill Exp $ */ 2 3 /*- 4 * Copyright (c) 2017-2019 Jared McNeill <jmcneill@invisible.ca> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: meson_clk_div.c,v 1.3 2019/02/25 19:30:17 jmcneill Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/bus.h> 34 35 #include <dev/clk/clk_backend.h> 36 37 #include <arm/amlogic/meson_clk.h> 38 39 u_int 40 meson_clk_div_get_rate(struct meson_clk_softc *sc, 41 struct meson_clk_clk *clk) 42 { 43 struct meson_clk_div *div = &clk->u.div; 44 struct clk *clkp, *clkp_parent; 45 u_int rate, ratio; 46 uint32_t val; 47 48 KASSERT(clk->type == MESON_CLK_DIV); 49 50 clkp = &clk->base; 51 clkp_parent = clk_get_parent(clkp); 52 if (clkp_parent == NULL) 53 return 0; 54 55 rate = clk_get_rate(clkp_parent); 56 if (rate == 0) 57 return 0; 58 59 CLK_LOCK(sc); 60 val = CLK_READ(sc, div->reg); 61 CLK_UNLOCK(sc); 62 63 if (div->div) 64 ratio = __SHIFTOUT(val, div->div); 65 else 66 ratio = 0; 67 68 if (div->flags & MESON_CLK_DIV_POWER_OF_TWO) { 69 return rate >> ratio; 70 } else if (div->flags & MESON_CLK_DIV_CPU_SCALE_TABLE) { 71 if (ratio < 1 || ratio > 8) 72 return 0; 73 return rate / ((ratio + 1) * 2); 74 } else { 75 return rate / (ratio + 1); 76 } 77 } 78 79 int 80 meson_clk_div_set_rate(struct meson_clk_softc *sc, 81 struct meson_clk_clk *clk, u_int new_rate) 82 { 83 struct meson_clk_div *div = &clk->u.div; 84 struct clk *clkp, *clkp_parent; 85 int parent_rate; 86 uint32_t val, raw_div; 87 int ratio, error; 88 89 KASSERT(clk->type == MESON_CLK_DIV); 90 91 clkp = &clk->base; 92 clkp_parent = clk_get_parent(clkp); 93 if (clkp_parent == NULL) 94 return ENXIO; 95 96 if ((div->flags & MESON_CLK_DIV_SET_RATE_PARENT) != 0) 97 return clk_set_rate(clkp_parent, new_rate); 98 99 if (div->div == 0) 100 return ENXIO; 101 102 CLK_LOCK(sc); 103 104 val = CLK_READ(sc, div->reg); 105 106 parent_rate = clk_get_rate(clkp_parent); 107 if (parent_rate == 0) { 108 error = (new_rate == 0) ? 0 : ERANGE; 109 goto done; 110 } 111 112 ratio = howmany(parent_rate, new_rate); 113 if ((div->flags & MESON_CLK_DIV_POWER_OF_TWO) != 0) { 114 error = EINVAL; 115 goto done; 116 } else if ((div->flags & MESON_CLK_DIV_CPU_SCALE_TABLE) != 0) { 117 error = EINVAL; 118 goto done; 119 } else { 120 raw_div = (ratio > 0) ? ratio - 1 : 0; 121 } 122 if (raw_div > __SHIFTOUT_MASK(div->div)) { 123 error = ERANGE; 124 goto done; 125 } 126 127 val &= ~div->div; 128 val |= __SHIFTIN(raw_div, div->div); 129 CLK_WRITE(sc, div->reg, val); 130 131 error = 0; 132 133 done: 134 CLK_UNLOCK(sc); 135 136 return error; 137 } 138 139 const char * 140 meson_clk_div_get_parent(struct meson_clk_softc *sc, 141 struct meson_clk_clk *clk) 142 { 143 struct meson_clk_div *div = &clk->u.div; 144 145 KASSERT(clk->type == MESON_CLK_DIV); 146 147 return div->parent; 148 } 149