drivers/net/dsa/mv88e6xxx/global1_atu.c

   1 /*
   2  * Marvell 88E6xxx Address Translation Unit (ATU) support
   3  *
   4  * Copyright (c) 2008 Marvell Semiconductor
   5  * Copyright (c) 2017 Savoir-faire Linux, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include "mv88e6xxx.h"
  14 #include "global1.h"
  15
  16 /* Offset 0x0A: ATU Control Register */
  17
  18 int mv88e6xxx_g1_atu_set_age_time(struct mv88e6xxx_chip *chip,
  19                                   unsigned int msecs)
  20 {
  21         const unsigned int coeff = chip->info->age_time_coeff;
  22         const unsigned int min = 0x01 * coeff;
  23         const unsigned int max = 0xff * coeff;
  24         u8 age_time;
  25         u16 val;
  26         int err;
  27
  28         if (msecs < min || msecs > max)
  29                 return -ERANGE;
  30
  31         /* Round to nearest multiple of coeff */
  32         age_time = (msecs + coeff / 2) / coeff;
  33
  34         err = mv88e6xxx_g1_read(chip, GLOBAL_ATU_CONTROL, &val);
  35         if (err)
  36                 return err;
  37
  38         /* AgeTime is 11:4 bits */
  39         val &= ~0xff0;
  40         val |= age_time << 4;
  41
  42         return mv88e6xxx_g1_write(chip, GLOBAL_ATU_CONTROL, val);
  43 }