/* 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.
 * (C) Copyright David Gibson, IBM Corp. 2001-2003.
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>

#include "hermes.h"

/* 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 DMSG(stuff...) do {printk(KERN_DEBUG "hermes @ %p: " , 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,
			    u16 param1, u16 param2)
{
	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, param2);
	hermes_write_regn(hw, PARAM1, param1);
	hermes_write_regn(hw, PARAM0, param0);
	hermes_write_regn(hw, CMD, cmd);

	return 0;
}

/*
 * Function definitions
 */

/* For doing cmds that wipe the magic constant in SWSUPPORT0 */
int hermes_doicmd_wait(hermes_t *hw, u16 cmd,
		       u16 parm0, u16 parm1, u16 parm2,
		       struct hermes_response *resp)
{
	int err = 0;
	int k;
	u16 status, reg;

	err = hermes_issue_cmd(hw, cmd, parm0, parm1, parm2);
	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 @ %p: "
		       "Timeout waiting for card to reset (reg=0x%04x)!\n",
		       hw->iobase, reg);
		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;
}
EXPORT_SYMBOL(hermes_doicmd_wait);

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

int hermes_init(hermes_t *hw)
{
	u16 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_doicmd_wait(hw, HERMES_CMD_INIT, 0, 0, 0, NULL);

	return err;
}
EXPORT_SYMBOL(hermes_init);

/* 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,
		      struct hermes_response *resp)
{
	int err;
	int k;
	u16 reg;
	u16 status;

	err = hermes_issue_cmd(hw, cmd, parm0, 0, 0);
	if (err) {
		if (!hermes_present(hw)) {
			if (net_ratelimit())
				printk(KERN_WARNING "hermes @ %p: "
				       "Card removed while issuing command "
				       "0x%04x.\n", hw->iobase, cmd);
			err = -ENODEV;
		} else
			if (net_ratelimit())
				printk(KERN_ERR "hermes @ %p: "
				       "Error %d issuing command 0x%04x.\n",
				       hw->iobase, err, cmd);
		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 @ %p: Card removed "
		       "while waiting for command 0x%04x completion.\n",
		       hw->iobase, cmd);
		err = -ENODEV;
		goto out;
	}

	if (!(reg & HERMES_EV_CMD)) {
		printk(KERN_ERR "hermes @ %p: Timeout waiting for "
		       "command 0x%04x completion.\n", hw->iobase, cmd);
		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;
}
EXPORT_SYMBOL(hermes_docmd_wait);

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 @ %p: "
		       "Card removed waiting for frame allocation.\n",
		       hw->iobase);
		return -ENODEV;
	}

	if (!(reg & HERMES_EV_ALLOC)) {
		printk(KERN_ERR "hermes @ %p: "
		       "Timeout waiting for frame allocation\n",
		       hw->iobase);
		return -ETIMEDOUT;
	}

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

	return 0;
}
EXPORT_SYMBOL(hermes_allocate);

/* 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);
	}

	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 != offset) {
		printk(KERN_ERR "hermes @ %p: BAP%d offset %s: "
		       "reg=0x%x id=0x%x offset=0x%x\n", hw->iobase, bap,
		       (reg & HERMES_OFFSET_BUSY) ? "timeout" : "error",
		       reg, id, offset);

		if (reg & HERMES_OFFSET_BUSY)
			return -ETIMEDOUT;

		return -EIO;		/* error or wrong offset */
	}

	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, int 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;
}
EXPORT_SYMBOL(hermes_bap_pread);

/* Write a block of data to the chip's buffer, via the
 * BAP. Synchronization/serialization is the caller's problem.
 *
 * 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, int len,
		      u16 id, u16 offset)
{
	int dreg = bap ? HERMES_DATA1 : HERMES_DATA0;
	int err = 0;

	if (len < 0)
		return -EINVAL;

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

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

 out:
	return err;
}
EXPORT_SYMBOL(hermes_bap_pwrite);

/* 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 % 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 -ENODATA;

	rtype = hermes_read_reg(hw, dreg);

	if (length)
		*length = rlength;

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

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_bytes(hw, dreg, value, count << 1);

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

	return err;
}
EXPORT_SYMBOL(hermes_write_ltv);