/*
 * Serial Attached SCSI (SAS) Expander discovery and configuration
 *
 * Copyright (C) 2007 James E.J. Bottomley
 *		<James.Bottomley@HansenPartnership.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; version 2 only.
 */
#include <linux/scatterlist.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/export.h>

#include "sas_internal.h"

#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_sas.h>
#include "../scsi_sas_internal.h"

static void sas_host_smp_discover(struct sas_ha_struct *sas_ha, u8 *resp_data,
				  u8 phy_id)
{
	struct sas_phy *phy;
	struct sas_rphy *rphy;

	if (phy_id >= sas_ha->num_phys) {
		resp_data[2] = SMP_RESP_NO_PHY;
		return;
	}
	resp_data[2] = SMP_RESP_FUNC_ACC;

	phy = sas_ha->sas_phy[phy_id]->phy;
	resp_data[9] = phy_id;
	resp_data[13] = phy->negotiated_linkrate;
	memcpy(resp_data + 16, sas_ha->sas_addr, SAS_ADDR_SIZE);
	memcpy(resp_data + 24, sas_ha->sas_phy[phy_id]->attached_sas_addr,
	       SAS_ADDR_SIZE);
	resp_data[40] = (phy->minimum_linkrate << 4) |
		phy->minimum_linkrate_hw;
	resp_data[41] = (phy->maximum_linkrate << 4) |
		phy->maximum_linkrate_hw;

	if (!sas_ha->sas_phy[phy_id]->port ||
	    !sas_ha->sas_phy[phy_id]->port->port_dev)
		return;

	rphy = sas_ha->sas_phy[phy_id]->port->port_dev->rphy;
	resp_data[12] = rphy->identify.device_type << 4;
	resp_data[14] = rphy->identify.initiator_port_protocols;
	resp_data[15] = rphy->identify.target_port_protocols;
}

/**
 * to_sas_gpio_gp_bit - given the gpio frame data find the byte/bit position of 'od'
 * @od: od bit to find
 * @data: incoming bitstream (from frame)
 * @index: requested data register index (from frame)
 * @count: total number of registers in the bitstream (from frame)
 * @bit: bit position of 'od' in the returned byte
 *
 * returns NULL if 'od' is not in 'data'
 *
 * From SFF-8485 v0.7:
 * "In GPIO_TX[1], bit 0 of byte 3 contains the first bit (i.e., OD0.0)
 *  and bit 7 of byte 0 contains the 32nd bit (i.e., OD10.1).
 *
 *  In GPIO_TX[2], bit 0 of byte 3 contains the 33rd bit (i.e., OD10.2)
 *  and bit 7 of byte 0 contains the 64th bit (i.e., OD21.0)."
 *
 * The general-purpose (raw-bitstream) RX registers have the same layout
 * although 'od' is renamed 'id' for 'input data'.
 *
 * SFF-8489 defines the behavior of the LEDs in response to the 'od' values.
 */
static u8 *to_sas_gpio_gp_bit(unsigned int od, u8 *data, u8 index, u8 count, u8 *bit)
{
	unsigned int reg;
	u8 byte;

	/* gp registers start at index 1 */
	if (index == 0)
		return NULL;

	index--; /* make index 0-based */
	if (od < index * 32)
		return NULL;

	od -= index * 32;
	reg = od >> 5;

	if (reg >= count)
		return NULL;

	od &= (1 << 5) - 1;
	byte = 3 - (od >> 3);
	*bit = od & ((1 << 3) - 1);

	return &data[reg * 4 + byte];
}

int try_test_sas_gpio_gp_bit(unsigned int od, u8 *data, u8 index, u8 count)
{
	u8 *byte;
	u8 bit;

	byte = to_sas_gpio_gp_bit(od, data, index, count, &bit);
	if (!byte)
		return -1;

	return (*byte >> bit) & 1;
}
EXPORT_SYMBOL(try_test_sas_gpio_gp_bit);

static int sas_host_smp_write_gpio(struct sas_ha_struct *sas_ha, u8 *resp_data,
				   u8 reg_type, u8 reg_index, u8 reg_count,
				   u8 *req_data)
{
	struct sas_internal *i = to_sas_internal(sas_ha->core.shost->transportt);
	int written;

	if (i->dft->lldd_write_gpio == NULL) {
		resp_data[2] = SMP_RESP_FUNC_UNK;
		return 0;
	}

	written = i->dft->lldd_write_gpio(sas_ha, reg_type, reg_index,
					  reg_count, req_data);

	if (written < 0) {
		resp_data[2] = SMP_RESP_FUNC_FAILED;
		written = 0;
	} else
		resp_data[2] = SMP_RESP_FUNC_ACC;

	return written;
}

static void sas_report_phy_sata(struct sas_ha_struct *sas_ha, u8 *resp_data,
				u8 phy_id)
{
	struct sas_rphy *rphy;
	struct dev_to_host_fis *fis;
	int i;

	if (phy_id >= sas_ha->num_phys) {
		resp_data[2] = SMP_RESP_NO_PHY;
		return;
	}

	resp_data[2] = SMP_RESP_PHY_NO_SATA;

	if (!sas_ha->sas_phy[phy_id]->port)
		return;

	rphy = sas_ha->sas_phy[phy_id]->port->port_dev->rphy;
	fis = (struct dev_to_host_fis *)
		sas_ha->sas_phy[phy_id]->port->port_dev->frame_rcvd;
	if (rphy->identify.target_port_protocols != SAS_PROTOCOL_SATA)
		return;

	resp_data[2] = SMP_RESP_FUNC_ACC;
	resp_data[9] = phy_id;
	memcpy(resp_data + 16, sas_ha->sas_phy[phy_id]->attached_sas_addr,
	       SAS_ADDR_SIZE);

	/* check to see if we have a valid d2h fis */
	if (fis->fis_type != 0x34)
		return;

	/* the d2h fis is required by the standard to be in LE format */
	for (i = 0; i < 20; i += 4) {
		u8 *dst = resp_data + 24 + i, *src =
			&sas_ha->sas_phy[phy_id]->port->port_dev->frame_rcvd[i];
		dst[0] = src[3];
		dst[1] = src[2];
		dst[2] = src[1];
		dst[3] = src[0];
	}
}

static void sas_phy_control(struct sas_ha_struct *sas_ha, u8 phy_id,
			    u8 phy_op, enum sas_linkrate min,
			    enum sas_linkrate max, u8 *resp_data)
{
	struct sas_internal *i =
		to_sas_internal(sas_ha->core.shost->transportt);
	struct sas_phy_linkrates rates;
	struct asd_sas_phy *asd_phy;

	if (phy_id >= sas_ha->num_phys) {
		resp_data[2] = SMP_RESP_NO_PHY;
		return;
	}

	asd_phy = sas_ha->sas_phy[phy_id];
	switch (phy_op) {
	case PHY_FUNC_NOP:
	case PHY_FUNC_LINK_RESET:
	case PHY_FUNC_HARD_RESET:
	case PHY_FUNC_DISABLE:
	case PHY_FUNC_CLEAR_ERROR_LOG:
	case PHY_FUNC_CLEAR_AFFIL:
	case PHY_FUNC_TX_SATA_PS_SIGNAL:
		break;

	default:
		resp_data[2] = SMP_RESP_PHY_UNK_OP;
		return;
	}

	rates.minimum_linkrate = min;
	rates.maximum_linkrate = max;

	/* filter reset requests through libata eh */
	if (phy_op == PHY_FUNC_LINK_RESET && sas_try_ata_reset(asd_phy) == 0) {
		resp_data[2] = SMP_RESP_FUNC_ACC;
		return;
	}

	if (i->dft->lldd_control_phy(asd_phy, phy_op, &rates))
		resp_data[2] = SMP_RESP_FUNC_FAILED;
	else
		resp_data[2] = SMP_RESP_FUNC_ACC;
}

int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
			 struct request *rsp)
{
	u8 *req_data = NULL, *resp_data = NULL, *buf;
	struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
	int error = -EINVAL;

	/* eight is the minimum size for request and response frames */
	if (blk_rq_bytes(req) < 8 || blk_rq_bytes(rsp) < 8)
		goto out;

	if (bio_offset(req->bio) + blk_rq_bytes(req) > PAGE_SIZE ||
	    bio_offset(rsp->bio) + blk_rq_bytes(rsp) > PAGE_SIZE) {
		shost_printk(KERN_ERR, shost,
			"SMP request/response frame crosses page boundary");
		goto out;
	}

	req_data = kzalloc(blk_rq_bytes(req), GFP_KERNEL);

	/* make sure frame can always be built ... we copy
	 * back only the requested length */
	resp_data = kzalloc(max(blk_rq_bytes(rsp), 128U), GFP_KERNEL);

	if (!req_data || !resp_data) {
		error = -ENOMEM;
		goto out;
	}

	local_irq_disable();
	buf = kmap_atomic(bio_page(req->bio), KM_USER0) + bio_offset(req->bio);
	memcpy(req_data, buf, blk_rq_bytes(req));
	kunmap_atomic(buf - bio_offset(req->bio), KM_USER0);
	local_irq_enable();

	if (req_data[0] != SMP_REQUEST)
		goto out;

	/* always succeeds ... even if we can't process the request
	 * the result is in the response frame */
	error = 0;

	/* set up default don't know response */
	resp_data[0] = SMP_RESPONSE;
	resp_data[1] = req_data[1];
	resp_data[2] = SMP_RESP_FUNC_UNK;

	switch (req_data[1]) {
	case SMP_REPORT_GENERAL:
		req->resid_len -= 8;
		rsp->resid_len -= 32;
		resp_data[2] = SMP_RESP_FUNC_ACC;
		resp_data[9] = sas_ha->num_phys;
		break;

	case SMP_REPORT_MANUF_INFO:
		req->resid_len -= 8;
		rsp->resid_len -= 64;
		resp_data[2] = SMP_RESP_FUNC_ACC;
		memcpy(resp_data + 12, shost->hostt->name,
		       SAS_EXPANDER_VENDOR_ID_LEN);
		memcpy(resp_data + 20, "libsas virt phy",
		       SAS_EXPANDER_PRODUCT_ID_LEN);
		break;

	case SMP_READ_GPIO_REG:
		/* FIXME: need GPIO support in the transport class */
		break;

	case SMP_DISCOVER:
		req->resid_len -= 16;
		if ((int)req->resid_len < 0) {
			req->resid_len = 0;
			error = -EINVAL;
			goto out;
		}
		rsp->resid_len -= 56;
		sas_host_smp_discover(sas_ha, resp_data, req_data[9]);
		break;

	case SMP_REPORT_PHY_ERR_LOG:
		/* FIXME: could implement this with additional
		 * libsas callbacks providing the HW supports it */
		break;

	case SMP_REPORT_PHY_SATA:
		req->resid_len -= 16;
		if ((int)req->resid_len < 0) {
			req->resid_len = 0;
			error = -EINVAL;
			goto out;
		}
		rsp->resid_len -= 60;
		sas_report_phy_sata(sas_ha, resp_data, req_data[9]);
		break;

	case SMP_REPORT_ROUTE_INFO:
		/* Can't implement; hosts have no routes */
		break;

	case SMP_WRITE_GPIO_REG: {
		/* SFF-8485 v0.7 */
		const int base_frame_size = 11;
		int to_write = req_data[4];

		if (blk_rq_bytes(req) < base_frame_size + to_write * 4 ||
		    req->resid_len < base_frame_size + to_write * 4) {
			resp_data[2] = SMP_RESP_INV_FRM_LEN;
			break;
		}

		to_write = sas_host_smp_write_gpio(sas_ha, resp_data, req_data[2],
						   req_data[3], to_write, &req_data[8]);
		req->resid_len -= base_frame_size + to_write * 4;
		rsp->resid_len -= 8;
		break;
	}

	case SMP_CONF_ROUTE_INFO:
		/* Can't implement; hosts have no routes */
		break;

	case SMP_PHY_CONTROL:
		req->resid_len -= 44;
		if ((int)req->resid_len < 0) {
			req->resid_len = 0;
			error = -EINVAL;
			goto out;
		}
		rsp->resid_len -= 8;
		sas_phy_control(sas_ha, req_data[9], req_data[10],
				req_data[32] >> 4, req_data[33] >> 4,
				resp_data);
		break;

	case SMP_PHY_TEST_FUNCTION:
		/* FIXME: should this be implemented? */
		break;

	default:
		/* probably a 2.0 function */
		break;
	}

	local_irq_disable();
	buf = kmap_atomic(bio_page(rsp->bio), KM_USER0) + bio_offset(rsp->bio);
	memcpy(buf, resp_data, blk_rq_bytes(rsp));
	flush_kernel_dcache_page(bio_page(rsp->bio));
	kunmap_atomic(buf - bio_offset(rsp->bio), KM_USER0);
	local_irq_enable();

 out:
	kfree(req_data);
	kfree(resp_data);
	return error;
}