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      1 /* $NetBSD: tegra_cpufreq.c,v 1.5 2017/04/22 23:53:24 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) 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 "locators.h"
     30 
     31 #include <sys/cdefs.h>
     32 __KERNEL_RCSID(0, "$NetBSD: tegra_cpufreq.c,v 1.5 2017/04/22 23:53:24 jmcneill Exp $");
     33 
     34 #include <sys/param.h>
     35 #include <sys/bus.h>
     36 #include <sys/device.h>
     37 #include <sys/intr.h>
     38 #include <sys/systm.h>
     39 #include <sys/kernel.h>
     40 #include <sys/atomic.h>
     41 #include <sys/kmem.h>
     42 #include <sys/sysctl.h>
     43 
     44 #include <arm/nvidia/tegra_var.h>
     45 
     46 static u_int cpufreq_busy;
     47 static struct sysctllog *cpufreq_log;
     48 static int cpufreq_node_target, cpufreq_node_current, cpufreq_node_available;
     49 
     50 static const struct tegra_cpufreq_func *cpufreq_func = NULL;
     51 
     52 static int	tegra_cpufreq_freq_helper(SYSCTLFN_PROTO);
     53 static char 	tegra_cpufreq_available[TEGRA_CPUFREQ_MAX * 5];
     54 
     55 #define cpufreq_set_rate	cpufreq_func->set_rate
     56 #define cpufreq_get_rate	cpufreq_func->get_rate
     57 #define cpufreq_get_available	cpufreq_func->get_available
     58 
     59 void
     60 tegra_cpufreq_register(const struct tegra_cpufreq_func *cf)
     61 {
     62 	const struct sysctlnode *node, *cpunode, *freqnode;
     63 	u_int availfreq[TEGRA_CPUFREQ_MAX];
     64 	size_t nfreq;
     65 	int error;
     66 
     67 	KASSERT(cpufreq_func == NULL);
     68 	cpufreq_func = cf;
     69 
     70 	nfreq = cpufreq_get_available(availfreq, TEGRA_CPUFREQ_MAX);
     71 	if (nfreq == 0)
     72 		return;
     73 
     74 	KASSERT(nfreq <= TEGRA_CPUFREQ_MAX);
     75 
     76 	for (int i = 0; i < nfreq; i++) {
     77 		char buf[6];
     78 		snprintf(buf, sizeof(buf), i ? " %u" : "%u", availfreq[i]);
     79 		strcat(tegra_cpufreq_available, buf);
     80 	}
     81 
     82 	error = sysctl_createv(&cpufreq_log, 0, NULL, &node,
     83 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "machdep", NULL,
     84 	    NULL, 0, NULL, 0, CTL_MACHDEP, CTL_EOL);
     85 	if (error)
     86 		goto sysctl_failed;
     87 	error = sysctl_createv(&cpufreq_log, 0, &node, &cpunode,
     88 	    0, CTLTYPE_NODE, "cpu", NULL,
     89 	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
     90 	if (error)
     91 		goto sysctl_failed;
     92 	error = sysctl_createv(&cpufreq_log, 0, &cpunode, &freqnode,
     93 	    0, CTLTYPE_NODE, "frequency", NULL,
     94 	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
     95 	if (error)
     96 		goto sysctl_failed;
     97 
     98 	error = sysctl_createv(&cpufreq_log, 0, &freqnode, &node,
     99 	    CTLFLAG_READWRITE, CTLTYPE_INT, "target", NULL,
    100 	    tegra_cpufreq_freq_helper, 0, NULL, 0,
    101 	    CTL_CREATE, CTL_EOL);
    102 	if (error)
    103 		goto sysctl_failed;
    104 	cpufreq_node_target = node->sysctl_num;
    105 
    106 	error = sysctl_createv(&cpufreq_log, 0, &freqnode, &node,
    107 	    CTLFLAG_READWRITE, CTLTYPE_INT, "current", NULL,
    108 	    tegra_cpufreq_freq_helper, 0, NULL, 0,
    109 	    CTL_CREATE, CTL_EOL);
    110 	if (error)
    111 		goto sysctl_failed;
    112 	cpufreq_node_current = node->sysctl_num;
    113 
    114 	error = sysctl_createv(&cpufreq_log, 0, &freqnode, &node,
    115 	    0, CTLTYPE_STRING, "available", NULL,
    116 	    NULL, 0, tegra_cpufreq_available, 0,
    117 	    CTL_CREATE, CTL_EOL);
    118 	if (error)
    119 		goto sysctl_failed;
    120 	cpufreq_node_available = node->sysctl_num;
    121 
    122 	device_printf(curcpu()->ci_dev,
    123 	    "setting speed to %d MHz\n", availfreq[0]);
    124 	cpufreq_set_rate(availfreq[0]);
    125 
    126 	return;
    127 
    128 sysctl_failed:
    129 	aprint_error("cpufreq: couldn't create sysctl nodes (%d)\n", error);
    130 	sysctl_teardown(&cpufreq_log);
    131 }
    132 
    133 static int
    134 tegra_cpufreq_freq_helper(SYSCTLFN_ARGS)
    135 {
    136 	struct sysctlnode node;
    137 	int fq, oldfq = 0, error;
    138 
    139 	node = *rnode;
    140 	node.sysctl_data = &fq;
    141 
    142 	fq = cpufreq_get_rate();
    143 	if (rnode->sysctl_num == cpufreq_node_target)
    144 		oldfq = fq;
    145 
    146 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
    147 	if (error || newp == NULL)
    148 		return error;
    149 
    150 	if (fq == oldfq || rnode->sysctl_num != cpufreq_node_target)
    151 		return 0;
    152 
    153 	if (atomic_cas_uint(&cpufreq_busy, 0, 1) != 0)
    154 		return EBUSY;
    155 
    156 	error = cpufreq_set_rate(fq);
    157 	if (error == 0) {
    158 		pmf_event_inject(NULL, PMFE_SPEED_CHANGED);
    159 	}
    160 
    161 	atomic_dec_uint(&cpufreq_busy);
    162 
    163 	return error;
    164 }
    165