arch/arm64/kernel/cacheinfo.c

   1 /*
   2  *  ARM64 cacheinfo support
   3  *
   4  *  Copyright (C) 2015 ARM Ltd.
   5  *  All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  12  * kind, whether express or implied; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/bitops.h>
  21 #include <linux/cacheinfo.h>
  22 #include <linux/cpu.h>
  23 #include <linux/compiler.h>
  24 #include <linux/of.h>
  25
  26 #include <asm/cachetype.h>
  27 #include <asm/processor.h>
  28
  29 #define MAX_CACHE_LEVEL                 7       /* Max 7 level supported */
  30 /* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
  31 #define CLIDR_CTYPE_SHIFT(level)        (3 * (level - 1))
  32 #define CLIDR_CTYPE_MASK(level)         (7 << CLIDR_CTYPE_SHIFT(level))
  33 #define CLIDR_CTYPE(clidr, level)       \
  34         (((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
  35
  36 static inline enum cache_type get_cache_type(int level)
  37 {
  38         u64 clidr;
  39
  40         if (level > MAX_CACHE_LEVEL)
  41                 return CACHE_TYPE_NOCACHE;
  42         clidr = read_sysreg(clidr_el1);
  43         return CLIDR_CTYPE(clidr, level);
  44 }
  45
  46 /*
  47  * Cache Size Selection Register(CSSELR) selects which Cache Size ID
  48  * Register(CCSIDR) is accessible by specifying the required cache
  49  * level and the cache type. We need to ensure that no one else changes
  50  * CSSELR by calling this in non-preemtible context
  51  */
  52 u64 __attribute_const__ cache_get_ccsidr(u64 csselr)
  53 {
  54         u64 ccsidr;
  55
  56         WARN_ON(preemptible());
  57
  58         write_sysreg(csselr, csselr_el1);
  59         isb();
  60         ccsidr = read_sysreg(ccsidr_el1);
  61
  62         return ccsidr;
  63 }
  64
  65 static void ci_leaf_init(struct cacheinfo *this_leaf,
  66                          enum cache_type type, unsigned int level)
  67 {
  68         bool is_icache = type & CACHE_TYPE_INST;
  69         u64 tmp = cache_get_ccsidr((level - 1) << 1 | is_icache);
  70
  71         this_leaf->level = level;
  72         this_leaf->type = type;
  73         this_leaf->coherency_line_size = CACHE_LINESIZE(tmp);
  74         this_leaf->number_of_sets = CACHE_NUMSETS(tmp);
  75         this_leaf->ways_of_associativity = CACHE_ASSOCIATIVITY(tmp);
  76         this_leaf->size = this_leaf->number_of_sets *
  77             this_leaf->coherency_line_size * this_leaf->ways_of_associativity;
  78         this_leaf->attributes =
  79                 ((tmp & CCSIDR_EL1_WRITE_THROUGH) ? CACHE_WRITE_THROUGH : 0) |
  80                 ((tmp & CCSIDR_EL1_WRITE_BACK) ? CACHE_WRITE_BACK : 0) |
  81                 ((tmp & CCSIDR_EL1_READ_ALLOCATE) ? CACHE_READ_ALLOCATE : 0) |
  82                 ((tmp & CCSIDR_EL1_WRITE_ALLOCATE) ? CACHE_WRITE_ALLOCATE : 0);
  83 }
  84
  85 static int __init_cache_level(unsigned int cpu)
  86 {
  87         unsigned int ctype, level, leaves, of_level;
  88         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  89
  90         for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
  91                 ctype = get_cache_type(level);
  92                 if (ctype == CACHE_TYPE_NOCACHE) {
  93                         level--;
  94                         break;
  95                 }
  96                 /* Separate instruction and data caches */
  97                 leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
  98         }
  99
 100         of_level = of_find_last_cache_level(cpu);
 101         if (level < of_level) {
 102                 /*
 103                  * some external caches not specified in CLIDR_EL1
 104                  * the information may be available in the device tree
 105                  * only unified external caches are considered here
 106                  */
 107                 leaves += (of_level - level);
 108                 level = of_level;
 109         }
 110
 111         this_cpu_ci->num_levels = level;
 112         this_cpu_ci->num_leaves = leaves;
 113         return 0;
 114 }
 115
 116 static int __populate_cache_leaves(unsigned int cpu)
 117 {
 118         unsigned int level, idx;
 119         enum cache_type type;
 120         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 121         struct cacheinfo *this_leaf = this_cpu_ci->info_list;
 122
 123         for (idx = 0, level = 1; level <= this_cpu_ci->num_levels &&
 124              idx < this_cpu_ci->num_leaves; idx++, level++) {
 125                 type = get_cache_type(level);
 126                 if (type == CACHE_TYPE_SEPARATE) {
 127                         ci_leaf_init(this_leaf++, CACHE_TYPE_DATA, level);
 128                         ci_leaf_init(this_leaf++, CACHE_TYPE_INST, level);
 129                 } else {
 130                         ci_leaf_init(this_leaf++, type, level);
 131                 }
 132         }
 133         return 0;
 134 }
 135
 136 DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
 137 DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)