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/export.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  * Returns with preemption disabled.
  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         preempt_disable();
  32         local_irq_save(flags);
  33         status = read_c0_status();
  34         write_c0_status(status | ST0_CU2);
  35         if (KSTK_STATUS(current) & ST0_CU2) {
  36                 octeon_cop2_save(&(current->thread.cp2));
  37                 KSTK_STATUS(current) &= ~ST0_CU2;
  38                 status &= ~ST0_CU2;
  39         } else if (status & ST0_CU2) {
  40                 octeon_cop2_save(state);
  41         }
  42         local_irq_restore(flags);
  43         return status & ST0_CU2;
  44 }
  45 EXPORT_SYMBOL_GPL(octeon_crypto_enable);
  46
  47 /**
  48  * Disable access to Octeon's COP2 crypto hardware in the kernel. This must be
  49  * called after an octeon_crypto_enable() before any context switch or return to
  50  * userspace.
  51  *
  52  * @state:      Pointer to COP2 state to restore
  53  * @flags:      Return value from octeon_crypto_enable()
  54  */
  55 void octeon_crypto_disable(struct octeon_cop2_state *state,
  56                            unsigned long crypto_flags)
  57 {
  58         unsigned long flags;
  59
  60         local_irq_save(flags);
  61         if (crypto_flags & ST0_CU2)
  62                 octeon_cop2_restore(state);
  63         else
  64                 write_c0_status(read_c0_status() & ~ST0_CU2);
  65         local_irq_restore(flags);
  66         preempt_enable();
  67 }
  68 EXPORT_SYMBOL_GPL(octeon_crypto_disable);