/*
 * Copyright 2009 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Ben Skeggs
 */

#include <subdev/i2c.h>

/******************************************************************************
 * aux channel util functions
 *****************************************************************************/
#define AUX_DBG(fmt, args...) nv_debug(aux, "AUXCH(%d): " fmt, ch, ##args)
#define AUX_ERR(fmt, args...) nv_error(aux, "AUXCH(%d): " fmt, ch, ##args)

static void
auxch_fini(struct nouveau_i2c *aux, int ch)
{
	nv_mask(aux, 0x00e4e4 + (ch * 0x50), 0x00310000, 0x00000000);
}

static int
auxch_init(struct nouveau_i2c *aux, int ch)
{
	const u32 unksel = 1; /* nfi which to use, or if it matters.. */
	const u32 ureq = unksel ? 0x00100000 : 0x00200000;
	const u32 urep = unksel ? 0x01000000 : 0x02000000;
	u32 ctrl, timeout;

	/* wait up to 1ms for any previous transaction to be done... */
	timeout = 1000;
	do {
		ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
		udelay(1);
		if (!timeout--) {
			AUX_ERR("begin idle timeout 0x%08x", ctrl);
			return -EBUSY;
		}
	} while (ctrl & 0x03010000);

	/* set some magic, and wait up to 1ms for it to appear */
	nv_mask(aux, 0x00e4e4 + (ch * 0x50), 0x00300000, ureq);
	timeout = 1000;
	do {
		ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
		udelay(1);
		if (!timeout--) {
			AUX_ERR("magic wait 0x%08x\n", ctrl);
			auxch_fini(aux, ch);
			return -EBUSY;
		}
	} while ((ctrl & 0x03000000) != urep);

	return 0;
}

static int
auxch_tx(struct nouveau_i2c *aux, int ch, u8 type, u32 addr, u8 *data, u8 size)
{
	u32 ctrl, stat, timeout, retries;
	u32 xbuf[4] = {};
	int ret, i;

	AUX_DBG("%d: 0x%08x %d\n", type, addr, size);

	ret = auxch_init(aux, ch);
	if (ret)
		goto out;

	stat = nv_rd32(aux, 0x00e4e8 + (ch * 0x50));
	if (!(stat & 0x10000000)) {
		AUX_DBG("sink not detected\n");
		ret = -ENXIO;
		goto out;
	}

	if (!(type & 1)) {
		memcpy(xbuf, data, size);
		for (i = 0; i < 16; i += 4) {
			AUX_DBG("wr 0x%08x\n", xbuf[i / 4]);
			nv_wr32(aux, 0x00e4c0 + (ch * 0x50) + i, xbuf[i / 4]);
		}
	}

	ctrl  = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
	ctrl &= ~0x0001f0ff;
	ctrl |= type << 12;
	ctrl |= size - 1;
	nv_wr32(aux, 0x00e4e0 + (ch * 0x50), addr);

	/* retry transaction a number of times on failure... */
	ret = -EREMOTEIO;
	for (retries = 0; retries < 32; retries++) {
		/* reset, and delay a while if this is a retry */
		nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x80000000 | ctrl);
		nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x00000000 | ctrl);
		if (retries)
			udelay(400);

		/* transaction request, wait up to 1ms for it to complete */
		nv_wr32(aux, 0x00e4e4 + (ch * 0x50), 0x00010000 | ctrl);

		timeout = 1000;
		do {
			ctrl = nv_rd32(aux, 0x00e4e4 + (ch * 0x50));
			udelay(1);
			if (!timeout--) {
				AUX_ERR("tx req timeout 0x%08x\n", ctrl);
				goto out;
			}
		} while (ctrl & 0x00010000);

		/* read status, and check if transaction completed ok */
		stat = nv_mask(aux, 0x00e4e8 + (ch * 0x50), 0, 0);
		if (!(stat & 0x000f0f00)) {
			ret = 0;
			break;
		}

		AUX_DBG("%02d 0x%08x 0x%08x\n", retries, ctrl, stat);
	}

	if (type & 1) {
		for (i = 0; i < 16; i += 4) {
			xbuf[i / 4] = nv_rd32(aux, 0x00e4d0 + (ch * 0x50) + i);
			AUX_DBG("rd 0x%08x\n", xbuf[i / 4]);
		}
		memcpy(data, xbuf, size);
	}

out:
	auxch_fini(aux, ch);
	return ret;
}

int
nv_rdaux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
{
	return auxch_tx(auxch->i2c, auxch->drive, 9, addr, data, size);
}

int
nv_wraux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
{
	return auxch_tx(auxch->i2c, auxch->drive, 8, addr, data, size);
}

static int
aux_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct nouveau_i2c_port *auxch = (struct nouveau_i2c_port *)adap;
	struct i2c_msg *msg = msgs;
	int ret, mcnt = num;

	while (mcnt--) {
		u8 remaining = msg->len;
		u8 *ptr = msg->buf;

		while (remaining) {
			u8 cnt = (remaining > 16) ? 16 : remaining;
			u8 cmd;

			if (msg->flags & I2C_M_RD)
				cmd = 1;
			else
				cmd = 0;

			if (mcnt || remaining > 16)
				cmd |= 4; /* MOT */

			ret = auxch_tx(auxch->i2c, auxch->drive, cmd,
				       msg->addr, ptr, cnt);
			if (ret < 0)
				return ret;

			ptr += cnt;
			remaining -= cnt;
		}

		msg++;
	}

	return num;
}

static u32
aux_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

const struct i2c_algorithm nouveau_i2c_aux_algo = {
	.master_xfer = aux_xfer,
	.functionality = aux_func
};