/*
 * 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;
}

void sas_smp_host_handler(struct bsg_job *job, struct Scsi_Host *shost)
{
        struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
        u8 *req_data, *resp_data;
        unsigned int reslen = 0;
        int error = -EINVAL;

        /* eight is the minimum size for request and response frames */
        if (job->request_payload.payload_len < 8 ||
            job->reply_payload.payload_len < 8)
                goto out;

        error = -ENOMEM;
        req_data = kzalloc(job->request_payload.payload_len, GFP_KERNEL);
        if (!req_data)
                goto out;
        sg_copy_to_buffer(job->request_payload.sg_list,
                          job->request_payload.sg_cnt, req_data,
                          job->request_payload.payload_len);

        /* make sure frame can always be built ... we copy
         * back only the requested length */
        resp_data = kzalloc(max(job->reply_payload.payload_len, 128U),
                        GFP_KERNEL);
        if (!resp_data)
                goto out_free_req;

        error = -EINVAL;
        if (req_data[0] != SMP_REQUEST)
                goto out_free_resp;

        /* 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:
                resp_data[2] = SMP_RESP_FUNC_ACC;
                resp_data[9] = sas_ha->num_phys;
                reslen = 32;
                break;

        case SMP_REPORT_MANUF_INFO:
                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);
                reslen = 64;
                break;

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

        case SMP_DISCOVER:
                if (job->request_payload.payload_len < 16)
                        goto out_free_resp;
                sas_host_smp_discover(sas_ha, resp_data, req_data[9]);
                reslen = 56;
                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:
                if (job->request_payload.payload_len < 16)
                        goto out_free_resp;
                sas_report_phy_sata(sas_ha, resp_data, req_data[9]);
                reslen = 60;
                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 (job->request_payload.payload_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]);
                reslen = 8;
                break;
        }

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

        case SMP_PHY_CONTROL:
                if (job->request_payload.payload_len < 44)
                        goto out_free_resp;
                sas_phy_control(sas_ha, req_data[9], req_data[10],
                                req_data[32] >> 4, req_data[33] >> 4,
                                resp_data);
                reslen = 8;
                break;

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

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

        sg_copy_from_buffer(job->reply_payload.sg_list,
                            job->reply_payload.sg_cnt, resp_data,
                            job->reply_payload.payload_len);

        error = 0;
out_free_resp:
        kfree(resp_data);
out_free_req:
        kfree(req_data);
out:
        bsg_job_done(job, error, reslen);
}