arch/arm/common/krait-l2-accessors.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018, The Linux Foundation. All rights reserved.
   3
   4 #include <linux/spinlock.h>
   5 #include <linux/export.h>
   6
   7 #include <asm/barrier.h>
   8 #include <asm/krait-l2-accessors.h>
   9
  10 static DEFINE_RAW_SPINLOCK(krait_l2_lock);
  11
  12 void krait_set_l2_indirect_reg(u32 addr, u32 val)
  13 {
  14         unsigned long flags;
  15
  16         raw_spin_lock_irqsave(&krait_l2_lock, flags);
  17         /*
  18          * Select the L2 window by poking l2cpselr, then write to the window
  19          * via l2cpdr.
  20          */
  21         asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr));
  22         isb();
  23         asm volatile ("mcr p15, 3, %0, c15, c0, 7 @ l2cpdr" : : "r" (val));
  24         isb();
  25
  26         raw_spin_unlock_irqrestore(&krait_l2_lock, flags);
  27 }
  28 EXPORT_SYMBOL(krait_set_l2_indirect_reg);
  29
  30 u32 krait_get_l2_indirect_reg(u32 addr)
  31 {
  32         u32 val;
  33         unsigned long flags;
  34
  35         raw_spin_lock_irqsave(&krait_l2_lock, flags);
  36         /*
  37          * Select the L2 window by poking l2cpselr, then read from the window
  38          * via l2cpdr.
  39          */
  40         asm volatile ("mcr p15, 3, %0, c15, c0, 6 @ l2cpselr" : : "r" (addr));
  41         isb();
  42         asm volatile ("mrc p15, 3, %0, c15, c0, 7 @ l2cpdr" : "=r" (val));
  43
  44         raw_spin_unlock_irqrestore(&krait_l2_lock, flags);
  45
  46         return val;
  47 }
  48 EXPORT_SYMBOL(krait_get_l2_indirect_reg);