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hermes.c

/* hermes.c
 *
 * Driver core for the "Hermes" wireless MAC controller, as used in
 * the Lucent Orinoco and Cabletron RoamAbout cards. It should also
 * work on the hfa3841 and hfa3842 MAC controller chips used in the
 * Prism II chipsets.
 *
 * This is not a complete driver, just low-level access routines for
 * the MAC controller itself.
 *
 * Based on the prism2 driver from Absolute Value Systems' linux-wlan
 * project, the Linux wvlan_cs driver, Lucent's HCF-Light
 * (wvlan_hcf.c) library, and the NetBSD wireless driver (in no
 * particular order).
 *
 * Copyright (C) 2000, David Gibson, Linuxcare Australia <hermes@gibson.dropbear.id.au>
 * Copyright (C) 2001, David Gibson, IBM <hermes@gibson.dropbear.id.au>
 * 
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License
 * at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and
 * limitations under the License.
 *
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License version 2 (the "GPL"), in
 * which case the provisions of the GPL are applicable instead of the
 * above.  If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the MPL, indicate your decision by
 * deleting the provisions above and replace them with the notice and
 * other provisions required by the GPL.  If you do not delete the
 * provisions above, a recipient may use your version of this file
 * under either the MPL or the GPL.
 */

#include <linux/config.h>

#include <linux/module.h>
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <asm/io.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <asm/errno.h>

#include "hermes.h"

MODULE_DESCRIPTION("Low-level driver helper for Lucent Hermes chipset and Prism II HFA384x wireless MAC controller");
MODULE_AUTHOR("David Gibson <hermes@gibson.dropbear.id.au>");
#ifdef MODULE_LICENSE
MODULE_LICENSE("Dual MPL/GPL");
#endif

/* These are maximum timeouts. Most often, card wil react much faster */
#define CMD_BUSY_TIMEOUT (100) /* In iterations of ~1us */
#define CMD_INIT_TIMEOUT (50000) /* in iterations of ~10us */
#define CMD_COMPL_TIMEOUT (20000) /* in iterations of ~10us */
#define ALLOC_COMPL_TIMEOUT (1000) /* in iterations of ~10us */

/*
 * Debugging helpers
 */

#define IO_TYPE(hw)     ((hw)->io_space ? "IO " : "MEM ")
#define DMSG(stuff...) do {printk(KERN_DEBUG "hermes @ %s0x%x: " , IO_TYPE(hw), hw->iobase); \
                  printk(stuff);} while (0)

#undef HERMES_DEBUG
#ifdef HERMES_DEBUG
#include <stdarg.h>

#define DEBUG(lvl, stuff...) if ( (lvl) <= HERMES_DEBUG) DMSG(stuff)

#else /* ! HERMES_DEBUG */

#define DEBUG(lvl, stuff...) do { } while (0)

#endif /* ! HERMES_DEBUG */


/*
 * Internal functions
 */

/* Issue a command to the chip. Waiting for it to complete is the caller's
   problem.

   Returns -EBUSY if the command register is busy, 0 on success.

   Callable from any context.
*/
static int hermes_issue_cmd(hermes_t *hw, u16 cmd, u16 param0)
{
      int k = CMD_BUSY_TIMEOUT;
      u16 reg;

      /* First wait for the command register to unbusy */
      reg = hermes_read_regn(hw, CMD);
      while ( (reg & HERMES_CMD_BUSY) && k ) {
            k--;
            udelay(1);
            reg = hermes_read_regn(hw, CMD);
      }
      if (reg & HERMES_CMD_BUSY) {
            return -EBUSY;
      }

      hermes_write_regn(hw, PARAM2, 0);
      hermes_write_regn(hw, PARAM1, 0);
      hermes_write_regn(hw, PARAM0, param0);
      hermes_write_regn(hw, CMD, cmd);
      
      return 0;
}

/*
 * Function definitions
 */

void hermes_struct_init(hermes_t *hw, ulong address,
                  int io_space, int reg_spacing)
{
      hw->iobase = address;
      hw->io_space = io_space;
      hw->reg_spacing = reg_spacing;
      hw->inten = 0x0;

#ifdef HERMES_DEBUG_BUFFER
      hw->dbufp = 0;
      memset(&hw->dbuf, 0xff, sizeof(hw->dbuf));
      memset(&hw->profile, 0, sizeof(hw->profile));
#endif
}

int hermes_init(hermes_t *hw)
{
      u16 status, reg;
      int err = 0;
      int k;

      /* We don't want to be interrupted while resetting the chipset */
      hw->inten = 0x0;
      hermes_write_regn(hw, INTEN, 0);
      hermes_write_regn(hw, EVACK, 0xffff);

      /* Normally it's a "can't happen" for the command register to
           be busy when we go to issue a command because we are
           serializing all commands.  However we want to have some
           chance of resetting the card even if it gets into a stupid
           state, so we actually wait to see if the command register
           will unbusy itself here. */
      k = CMD_BUSY_TIMEOUT;
      reg = hermes_read_regn(hw, CMD);
      while (k && (reg & HERMES_CMD_BUSY)) {
            if (reg == 0xffff) /* Special case - the card has probably been removed,
                              so don't wait for the timeout */
                  return -ENODEV;

            k--;
            udelay(1);
            reg = hermes_read_regn(hw, CMD);
      }
      
      /* No need to explicitly handle the timeout - if we've timed
         out hermes_issue_cmd() will probably return -EBUSY below */

      /* According to the documentation, EVSTAT may contain
         obsolete event occurrence information.  We have to acknowledge
         it by writing EVACK. */
      reg = hermes_read_regn(hw, EVSTAT);
      hermes_write_regn(hw, EVACK, reg);

      /* We don't use hermes_docmd_wait here, because the reset wipes
         the magic constant in SWSUPPORT0 away, and it gets confused */
      err = hermes_issue_cmd(hw, HERMES_CMD_INIT, 0);
      if (err)
            return err;

      reg = hermes_read_regn(hw, EVSTAT);
      k = CMD_INIT_TIMEOUT;
      while ( (! (reg & HERMES_EV_CMD)) && k) {
            k--;
            udelay(10);
            reg = hermes_read_regn(hw, EVSTAT);
      }

      hermes_write_regn(hw, SWSUPPORT0, HERMES_MAGIC);

      if (! hermes_present(hw)) {
            DEBUG(0, "hermes @ 0x%x: Card removed during reset.\n",
                   hw->iobase);
            err = -ENODEV;
            goto out;
      }
            
      if (! (reg & HERMES_EV_CMD)) {
            printk(KERN_ERR "hermes @ %s0x%lx: " 
                   "Timeout waiting for card to reset (reg=0x%04x)!\n",
                   IO_TYPE(hw), hw->iobase, reg);
            err = -ETIMEDOUT;
            goto out;
      }

      status = hermes_read_regn(hw, STATUS);

      hermes_write_regn(hw, EVACK, HERMES_EV_CMD);

      if (status & HERMES_STATUS_RESULT)
            err = -EIO;

 out:
      return err;
}

/* Issue a command to the chip, and (busy!) wait for it to
 * complete.
 *
 * Returns: < 0 on internal error, 0 on success, > 0 on error returned by the firmware
 *
 * Callable from any context, but locking is your problem. */
int hermes_docmd_wait(hermes_t *hw, u16 cmd, u16 parm0,
                  hermes_response_t *resp)
{
      int err;
      int k;
      u16 reg;
      u16 status;

      err = hermes_issue_cmd(hw, cmd, parm0);
      if (err) {
            if (! hermes_present(hw)) {
                  printk(KERN_WARNING "hermes @ %s0x%lx: "
                         "Card removed while issuing command.\n",
                         IO_TYPE(hw), hw->iobase);
                  err = -ENODEV;
            } else 
                  printk(KERN_ERR "hermes @ %s0x%lx: Error %d issuing command.\n",
                         IO_TYPE(hw), hw->iobase, err);
            goto out;
      }

      reg = hermes_read_regn(hw, EVSTAT);
      k = CMD_COMPL_TIMEOUT;
      while ( (! (reg & HERMES_EV_CMD)) && k) {
            k--;
            udelay(10);
            reg = hermes_read_regn(hw, EVSTAT);
      }

      if (! hermes_present(hw)) {
            printk(KERN_WARNING "hermes @ %s0x%lx: "
                   "Card removed while waiting for command completion.\n",
                   IO_TYPE(hw), hw->iobase);
            err = -ENODEV;
            goto out;
      }
            
      if (! (reg & HERMES_EV_CMD)) {
            printk(KERN_ERR "hermes @ %s0x%lx: "
                   "Timeout waiting for command completion.\n",
                   IO_TYPE(hw), hw->iobase);
            err = -ETIMEDOUT;
            goto out;
      }

      status = hermes_read_regn(hw, STATUS);
      if (resp) {
            resp->status = status;
            resp->resp0 = hermes_read_regn(hw, RESP0);
            resp->resp1 = hermes_read_regn(hw, RESP1);
            resp->resp2 = hermes_read_regn(hw, RESP2);
      }

      hermes_write_regn(hw, EVACK, HERMES_EV_CMD);

      if (status & HERMES_STATUS_RESULT)
            err = -EIO;

 out:
      return err;
}

int hermes_allocate(hermes_t *hw, u16 size, u16 *fid)
{
      int err = 0;
      int k;
      u16 reg;
      
      if ( (size < HERMES_ALLOC_LEN_MIN) || (size > HERMES_ALLOC_LEN_MAX) )
            return -EINVAL;

      err = hermes_docmd_wait(hw, HERMES_CMD_ALLOC, size, NULL);
      if (err) {
            return err;
      }

      reg = hermes_read_regn(hw, EVSTAT);
      k = ALLOC_COMPL_TIMEOUT;
      while ( (! (reg & HERMES_EV_ALLOC)) && k) {
            k--;
            udelay(10);
            reg = hermes_read_regn(hw, EVSTAT);
      }
      
      if (! hermes_present(hw)) {
            printk(KERN_WARNING "hermes @ %s0x%lx: "
                   "Card removed waiting for frame allocation.\n",
                   IO_TYPE(hw), hw->iobase);
            return -ENODEV;
      }
            
      if (! (reg & HERMES_EV_ALLOC)) {
            printk(KERN_ERR "hermes @ %s0x%lx: "
                   "Timeout waiting for frame allocation\n",
                   IO_TYPE(hw), hw->iobase);
            return -ETIMEDOUT;
      }

      *fid = hermes_read_regn(hw, ALLOCFID);
      hermes_write_regn(hw, EVACK, HERMES_EV_ALLOC);
      
      return 0;
}


/* Set up a BAP to read a particular chunk of data from card's internal buffer.
 *
 * Returns: < 0 on internal failure (errno), 0 on success, >0 on error
 * from firmware
 *
 * Callable from any context */
static int hermes_bap_seek(hermes_t *hw, int bap, u16 id, u16 offset)
{
      int sreg = bap ? HERMES_SELECT1 : HERMES_SELECT0;
      int oreg = bap ? HERMES_OFFSET1 : HERMES_OFFSET0;
      int k;
      u16 reg;

      /* Paranoia.. */
      if ( (offset > HERMES_BAP_OFFSET_MAX) || (offset % 2) )
            return -EINVAL;

      k = HERMES_BAP_BUSY_TIMEOUT;
      reg = hermes_read_reg(hw, oreg);
      while ((reg & HERMES_OFFSET_BUSY) && k) {
            k--;
            udelay(1);
            reg = hermes_read_reg(hw, oreg);
      }

#ifdef HERMES_DEBUG_BUFFER
      hw->profile[HERMES_BAP_BUSY_TIMEOUT - k]++;

      if (k < HERMES_BAP_BUSY_TIMEOUT) {
            struct hermes_debug_entry *e = 
                  &hw->dbuf[(hw->dbufp++) % HERMES_DEBUG_BUFSIZE];
            e->bap = bap;
            e->id = id;
            e->offset = offset;
            e->cycles = HERMES_BAP_BUSY_TIMEOUT - k;
      }
#endif

      if (reg & HERMES_OFFSET_BUSY)
            return -ETIMEDOUT;

      /* Now we actually set up the transfer */
      hermes_write_reg(hw, sreg, id);
      hermes_write_reg(hw, oreg, offset);

      /* Wait for the BAP to be ready */
      k = HERMES_BAP_BUSY_TIMEOUT;
      reg = hermes_read_reg(hw, oreg);
      while ( (reg & (HERMES_OFFSET_BUSY | HERMES_OFFSET_ERR)) && k) {
            k--;
            udelay(1);
            reg = hermes_read_reg(hw, oreg);
      }

      if (reg & HERMES_OFFSET_BUSY) {
            return -ETIMEDOUT;
      }

      if (reg & HERMES_OFFSET_ERR) {
            return -EIO;
      }


      return 0;
}

/* Read a block of data from the chip's buffer, via the
 * BAP. Synchronization/serialization is the caller's problem.  len
 * must be even.
 *
 * Returns: < 0 on internal failure (errno), 0 on success, > 0 on error from firmware
 */
int hermes_bap_pread(hermes_t *hw, int bap, void *buf, unsigned len,
                 u16 id, u16 offset)
{
      int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
      int err = 0;

      if ( (len < 0) || (len % 2) )
            return -EINVAL;

      err = hermes_bap_seek(hw, bap, id, offset);
      if (err)
            goto out;

      /* Actually do the transfer */
      hermes_read_words(hw, dreg, buf, len/2);

 out:
      return err;
}

/* Write a block of data to the chip's buffer, via the
 * BAP. Synchronization/serialization is the caller's problem. len
 * must be even.
 *
 * Returns: < 0 on internal failure (errno), 0 on success, > 0 on error from firmware
 */
int hermes_bap_pwrite(hermes_t *hw, int bap, const void *buf, unsigned len,
                  u16 id, u16 offset)
{
      int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
      int err = 0;

      if ( (len < 0) || (len % 2) )
            return -EINVAL;

      err = hermes_bap_seek(hw, bap, id, offset);
      if (err)
            goto out;
      
      /* Actually do the transfer */
      hermes_write_words(hw, dreg, buf, len/2);

 out: 
      return err;
}

/* Read a Length-Type-Value record from the card.
 *
 * If length is NULL, we ignore the length read from the card, and
 * read the entire buffer regardless. This is useful because some of
 * the configuration records appear to have incorrect lengths in
 * practice.
 *
 * Callable from user or bh context.  */
int hermes_read_ltv(hermes_t *hw, int bap, u16 rid, unsigned bufsize,
                u16 *length, void *buf)
{
      int err = 0;
      int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
      u16 rlength, rtype;
      unsigned nwords;

      if ( (bufsize < 0) || (bufsize % 2) )
            return -EINVAL;

      err = hermes_docmd_wait(hw, HERMES_CMD_ACCESS, rid, NULL);
      if (err)
            return err;

      err = hermes_bap_seek(hw, bap, rid, 0);
      if (err)
            return err;

      rlength = hermes_read_reg(hw, dreg);

      if (! rlength)
            return -ENOENT;

      rtype = hermes_read_reg(hw, dreg);

      if (length)
            *length = rlength;

      if (rtype != rid)
            printk(KERN_WARNING "hermes @ %s0x%lx: "
                   "hermes_read_ltv(): rid  (0x%04x) does not match type (0x%04x)\n",
                   IO_TYPE(hw), hw->iobase, rid, rtype);
      if (HERMES_RECLEN_TO_BYTES(rlength) > bufsize)
            printk(KERN_WARNING "hermes @ %s0x%lx: "
                   "Truncating LTV record from %d to %d bytes. "
                   "(rid=0x%04x, len=0x%04x)\n",
                   IO_TYPE(hw), hw->iobase,
                   HERMES_RECLEN_TO_BYTES(rlength), bufsize, rid, rlength);

      nwords = min((unsigned)rlength - 1, bufsize / 2);
      hermes_read_words(hw, dreg, buf, nwords);

      return 0;
}

int hermes_write_ltv(hermes_t *hw, int bap, u16 rid, 
                 u16 length, const void *value)
{
      int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
      int err = 0;
      unsigned count;

      if (length == 0)
            return -EINVAL;

      err = hermes_bap_seek(hw, bap, rid, 0);
      if (err)
            return err;

      hermes_write_reg(hw, dreg, length);
      hermes_write_reg(hw, dreg, rid);

      count = length - 1;

      hermes_write_words(hw, dreg, value, count);

      err = hermes_docmd_wait(hw, HERMES_CMD_ACCESS | HERMES_CMD_WRITE, 
                        rid, NULL);

      return err;
}

EXPORT_SYMBOL(hermes_struct_init);
EXPORT_SYMBOL(hermes_init);
EXPORT_SYMBOL(hermes_docmd_wait);
EXPORT_SYMBOL(hermes_allocate);

EXPORT_SYMBOL(hermes_bap_pread);
EXPORT_SYMBOL(hermes_bap_pwrite);
EXPORT_SYMBOL(hermes_read_ltv);
EXPORT_SYMBOL(hermes_write_ltv);

static int __init init_hermes(void)
{
      return 0;
}

static void __exit exit_hermes(void)
{
}

module_init(init_hermes);
module_exit(exit_hermes);

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