arch/mips/mm/sc-r5k.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 1997, 2001 Ralf Baechle (ralf@gnu.org),
   4  * derived from r4xx0.c by David S. Miller (davem@davemloft.net).
   5  */
   6 #include <linux/init.h>
   7 #include <linux/kernel.h>
   8 #include <linux/sched.h>
   9 #include <linux/mm.h>
  10
  11 #include <asm/mipsregs.h>
  12 #include <asm/bcache.h>
  13 #include <asm/cacheops.h>
  14 #include <asm/page.h>
  15 #include <asm/mmu_context.h>
  16 #include <asm/r4kcache.h>
  17
  18 /* Secondary cache size in bytes, if present.  */
  19 static unsigned long scache_size;
  20
  21 #define SC_LINE 32
  22 #define SC_PAGE (128*SC_LINE)
  23
  24 static inline void blast_r5000_scache(void)
  25 {
  26         unsigned long start = INDEX_BASE;
  27         unsigned long end = start + scache_size;
  28
  29         while(start < end) {
  30                 cache_op(R5K_Page_Invalidate_S, start);
  31                 start += SC_PAGE;
  32         }
  33 }
  34
  35 static void r5k_dma_cache_inv_sc(unsigned long addr, unsigned long size)
  36 {
  37         unsigned long end, a;
  38
  39         /* Catch bad driver code */
  40         BUG_ON(size == 0);
  41
  42         if (size >= scache_size) {
  43                 blast_r5000_scache();
  44                 return;
  45         }
  46
  47         /* On the R5000 secondary cache we cannot
  48          * invalidate less than a page at a time.
  49          * The secondary cache is physically indexed, write-through.
  50          */
  51         a = addr & ~(SC_PAGE - 1);
  52         end = (addr + size - 1) & ~(SC_PAGE - 1);
  53         while (a <= end) {
  54                 cache_op(R5K_Page_Invalidate_S, a);
  55                 a += SC_PAGE;
  56         }
  57 }
  58
  59 static void r5k_sc_enable(void)
  60 {
  61         unsigned long flags;
  62
  63         local_irq_save(flags);
  64         set_c0_config(R5K_CONF_SE);
  65         blast_r5000_scache();
  66         local_irq_restore(flags);
  67 }
  68
  69 static void r5k_sc_disable(void)
  70 {
  71         unsigned long flags;
  72
  73         local_irq_save(flags);
  74         blast_r5000_scache();
  75         clear_c0_config(R5K_CONF_SE);
  76         local_irq_restore(flags);
  77 }
  78
  79 static inline int __init r5k_sc_probe(void)
  80 {
  81         unsigned long config = read_c0_config();
  82
  83         if (config & CONF_SC)
  84                 return 0;
  85
  86         scache_size = (512 * 1024) << ((config & R5K_CONF_SS) >> 20);
  87
  88         printk("R5000 SCACHE size %ldkB, linesize 32 bytes.\n",
  89                         scache_size >> 10);
  90
  91         return 1;
  92 }
  93
  94 static struct bcache_ops r5k_sc_ops = {
  95         .bc_enable = r5k_sc_enable,
  96         .bc_disable = r5k_sc_disable,
  97         .bc_wback_inv = r5k_dma_cache_inv_sc,
  98         .bc_inv = r5k_dma_cache_inv_sc
  99 };
 100
 101 void r5k_sc_init(void)
 102 {
 103         if (r5k_sc_probe()) {
 104                 r5k_sc_enable();
 105                 bcops = &r5k_sc_ops;
 106         }
 107 }