arch/mips/mm/sc-mips.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2006 Chris Dearman (chris@mips.com),
   4  */
   5 #include <linux/init.h>
   6 #include <linux/kernel.h>
   7 #include <linux/sched.h>
   8 #include <linux/mm.h>
   9
  10 #include <asm/cpu-type.h>
  11 #include <asm/mipsregs.h>
  12 #include <asm/bcache.h>
  13 #include <asm/cacheops.h>
  14 #include <asm/page.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/mmu_context.h>
  17 #include <asm/r4kcache.h>
  18 #include <asm/mips-cps.h>
  19 #include <asm/bootinfo.h>
  20
  21 /*
  22  * MIPS32/MIPS64 L2 cache handling
  23  */
  24
  25 /*
  26  * Writeback and invalidate the secondary cache before DMA.
  27  */
  28 static void mips_sc_wback_inv(unsigned long addr, unsigned long size)
  29 {
  30         blast_scache_range(addr, addr + size);
  31 }
  32
  33 /*
  34  * Invalidate the secondary cache before DMA.
  35  */
  36 static void mips_sc_inv(unsigned long addr, unsigned long size)
  37 {
  38         unsigned long lsize = cpu_scache_line_size();
  39         unsigned long almask = ~(lsize - 1);
  40
  41         cache_op(Hit_Writeback_Inv_SD, addr & almask);
  42         cache_op(Hit_Writeback_Inv_SD, (addr + size - 1) & almask);
  43         blast_inv_scache_range(addr, addr + size);
  44 }
  45
  46 static void mips_sc_enable(void)
  47 {
  48         /* L2 cache is permanently enabled */
  49 }
  50
  51 static void mips_sc_disable(void)
  52 {
  53         /* L2 cache is permanently enabled */
  54 }
  55
  56 static void mips_sc_prefetch_enable(void)
  57 {
  58         unsigned long pftctl;
  59
  60         if (mips_cm_revision() < CM_REV_CM2_5)
  61                 return;
  62
  63         /*
  64          * If there is one or more L2 prefetch unit present then enable
  65          * prefetching for both code & data, for all ports.
  66          */
  67         pftctl = read_gcr_l2_pft_control();
  68         if (pftctl & CM_GCR_L2_PFT_CONTROL_NPFT) {
  69                 pftctl &= ~CM_GCR_L2_PFT_CONTROL_PAGEMASK;
  70                 pftctl |= PAGE_MASK & CM_GCR_L2_PFT_CONTROL_PAGEMASK;
  71                 pftctl |= CM_GCR_L2_PFT_CONTROL_PFTEN;
  72                 write_gcr_l2_pft_control(pftctl);
  73
  74                 set_gcr_l2_pft_control_b(CM_GCR_L2_PFT_CONTROL_B_PORTID |
  75                                          CM_GCR_L2_PFT_CONTROL_B_CEN);
  76         }
  77 }
  78
  79 static void mips_sc_prefetch_disable(void)
  80 {
  81         if (mips_cm_revision() < CM_REV_CM2_5)
  82                 return;
  83
  84         clear_gcr_l2_pft_control(CM_GCR_L2_PFT_CONTROL_PFTEN);
  85         clear_gcr_l2_pft_control_b(CM_GCR_L2_PFT_CONTROL_B_PORTID |
  86                                    CM_GCR_L2_PFT_CONTROL_B_CEN);
  87 }
  88
  89 static bool mips_sc_prefetch_is_enabled(void)
  90 {
  91         unsigned long pftctl;
  92
  93         if (mips_cm_revision() < CM_REV_CM2_5)
  94                 return false;
  95
  96         pftctl = read_gcr_l2_pft_control();
  97         if (!(pftctl & CM_GCR_L2_PFT_CONTROL_NPFT))
  98                 return false;
  99         return !!(pftctl & CM_GCR_L2_PFT_CONTROL_PFTEN);
 100 }
 101
 102 static struct bcache_ops mips_sc_ops = {
 103         .bc_enable = mips_sc_enable,
 104         .bc_disable = mips_sc_disable,
 105         .bc_wback_inv = mips_sc_wback_inv,
 106         .bc_inv = mips_sc_inv,
 107         .bc_prefetch_enable = mips_sc_prefetch_enable,
 108         .bc_prefetch_disable = mips_sc_prefetch_disable,
 109         .bc_prefetch_is_enabled = mips_sc_prefetch_is_enabled,
 110 };
 111
 112 /*
 113  * Check if the L2 cache controller is activated on a particular platform.
 114  * MTI's L2 controller and the L2 cache controller of Broadcom's BMIPS
 115  * cores both use c0_config2's bit 12 as "L2 Bypass" bit, that is the
 116  * cache being disabled.  However there is no guarantee for this to be
 117  * true on all platforms.  In an act of stupidity the spec defined bits
 118  * 12..15 as implementation defined so below function will eventually have
 119  * to be replaced by a platform specific probe.
 120  */
 121 static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
 122 {
 123         unsigned int config2 = read_c0_config2();
 124         unsigned int tmp;
 125
 126         /* Check the bypass bit (L2B) */
 127         switch (current_cpu_type()) {
 128         case CPU_34K:
 129         case CPU_74K:
 130         case CPU_1004K:
 131         case CPU_1074K:
 132         case CPU_INTERAPTIV:
 133         case CPU_PROAPTIV:
 134         case CPU_P5600:
 135         case CPU_BMIPS5000:
 136         case CPU_QEMU_GENERIC:
 137         case CPU_P6600:
 138                 if (config2 & (1 << 12))
 139                         return 0;
 140         }
 141
 142         tmp = (config2 >> 4) & 0x0f;
 143         if (0 < tmp && tmp <= 7)
 144                 c->scache.linesz = 2 << tmp;
 145         else
 146                 return 0;
 147         return 1;
 148 }
 149
 150 static int __init mips_sc_probe_cm3(void)
 151 {
 152         struct cpuinfo_mips *c = &current_cpu_data;
 153         unsigned long cfg = read_gcr_l2_config();
 154         unsigned long sets, line_sz, assoc;
 155
 156         if (cfg & CM_GCR_L2_CONFIG_BYPASS)
 157                 return 0;
 158
 159         sets = cfg & CM_GCR_L2_CONFIG_SET_SIZE;
 160         sets >>= __ffs(CM_GCR_L2_CONFIG_SET_SIZE);
 161         if (sets)
 162                 c->scache.sets = 64 << sets;
 163
 164         line_sz = cfg & CM_GCR_L2_CONFIG_LINE_SIZE;
 165         line_sz >>= __ffs(CM_GCR_L2_CONFIG_LINE_SIZE);
 166         if (line_sz)
 167                 c->scache.linesz = 2 << line_sz;
 168
 169         assoc = cfg & CM_GCR_L2_CONFIG_ASSOC;
 170         assoc >>= __ffs(CM_GCR_L2_CONFIG_ASSOC);
 171         c->scache.ways = assoc + 1;
 172         c->scache.waysize = c->scache.sets * c->scache.linesz;
 173         c->scache.waybit = __ffs(c->scache.waysize);
 174
 175         if (c->scache.linesz) {
 176                 c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
 177                 c->options |= MIPS_CPU_INCLUSIVE_CACHES;
 178                 return 1;
 179         }
 180
 181         return 0;
 182 }
 183
 184 static inline int __init mips_sc_probe(void)
 185 {
 186         struct cpuinfo_mips *c = &current_cpu_data;
 187         unsigned int config1, config2;
 188         unsigned int tmp;
 189
 190         /* Mark as not present until probe completed */
 191         c->scache.flags |= MIPS_CACHE_NOT_PRESENT;
 192
 193         if (mips_cm_revision() >= CM_REV_CM3)
 194                 return mips_sc_probe_cm3();
 195
 196         /* Ignore anything but MIPSxx processors */
 197         if (!(c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M32R2 |
 198                               MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R1 |
 199                               MIPS_CPU_ISA_M64R2 | MIPS_CPU_ISA_M64R6)))
 200                 return 0;
 201
 202         /* Does this MIPS32/MIPS64 CPU have a config2 register? */
 203         config1 = read_c0_config1();
 204         if (!(config1 & MIPS_CONF_M))
 205                 return 0;
 206
 207         config2 = read_c0_config2();
 208
 209         if (!mips_sc_is_activated(c))
 210                 return 0;
 211
 212         tmp = (config2 >> 8) & 0x0f;
 213         if (tmp <= 7)
 214                 c->scache.sets = 64 << tmp;
 215         else
 216                 return 0;
 217
 218         tmp = (config2 >> 0) & 0x0f;
 219         if (tmp <= 7)
 220                 c->scache.ways = tmp + 1;
 221         else
 222                 return 0;
 223
 224         /*
 225          * According to config2 it would be 5-ways, but that is contradicted
 226          * by all documentation.
 227          */
 228         if (current_cpu_type() == CPU_JZRISC &&
 229                                 mips_machtype == MACH_INGENIC_JZ4770)
 230                 c->scache.ways = 4;
 231
 232         c->scache.waysize = c->scache.sets * c->scache.linesz;
 233         c->scache.waybit = __ffs(c->scache.waysize);
 234
 235         c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
 236
 237         return 1;
 238 }
 239
 240 int mips_sc_init(void)
 241 {
 242         int found = mips_sc_probe();
 243         if (found) {
 244                 mips_sc_enable();
 245                 mips_sc_prefetch_enable();
 246                 bcops = &mips_sc_ops;
 247         }
 248         return found;
 249 }