arch/mips/cavium-octeon/crypto/octeon-crypto.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License. See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2004-2012 Cavium Networks
   7  */
   8
   9 #include <asm/cop2.h>
  10 #include <linux/module.h>
  11 #include <linux/interrupt.h>
  12
  13 #include "octeon-crypto.h"
  14
  15 /**
  16  * Enable access to Octeon's COP2 crypto hardware for kernel use. Wrap any
  17  * crypto operations in calls to octeon_crypto_enable/disable in order to make
  18  * sure the state of COP2 isn't corrupted if userspace is also performing
  19  * hardware crypto operations. Allocate the state parameter on the stack.
  20  * Preemption must be disabled to prevent context switches.
  21  *
  22  * @state: Pointer to state structure to store current COP2 state in.
  23  *
  24  * Returns: Flags to be passed to octeon_crypto_disable()
  25  */
  26 unsigned long octeon_crypto_enable(struct octeon_cop2_state *state)
  27 {
  28         int status;
  29         unsigned long flags;
  30
  31         local_irq_save(flags);
  32         status = read_c0_status();
  33         write_c0_status(status | ST0_CU2);
  34         if (KSTK_STATUS(current) & ST0_CU2) {
  35                 octeon_cop2_save(&(current->thread.cp2));
  36                 KSTK_STATUS(current) &= ~ST0_CU2;
  37                 status &= ~ST0_CU2;
  38         } else if (status & ST0_CU2) {
  39                 octeon_cop2_save(state);
  40         }
  41         local_irq_restore(flags);
  42         return status & ST0_CU2;
  43 }
  44 EXPORT_SYMBOL_GPL(octeon_crypto_enable);
  45
  46 /**
  47  * Disable access to Octeon's COP2 crypto hardware in the kernel. This must be
  48  * called after an octeon_crypto_enable() before any context switch or return to
  49  * userspace.
  50  *
  51  * @state:      Pointer to COP2 state to restore
  52  * @flags:      Return value from octeon_crypto_enable()
  53  */
  54 void octeon_crypto_disable(struct octeon_cop2_state *state,
  55                            unsigned long crypto_flags)
  56 {
  57         unsigned long flags;
  58
  59         local_irq_save(flags);
  60         if (crypto_flags & ST0_CU2)
  61                 octeon_cop2_restore(state);
  62         else
  63                 write_c0_status(read_c0_status() & ~ST0_CU2);
  64         local_irq_restore(flags);
  65 }
  66 EXPORT_SYMBOL_GPL(octeon_crypto_disable);