/*
 * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
 *
 * 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 (including the next
 * paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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:
 *    Ke Yu
 *    Zhiyuan Lv <zhiyuan.lv@intel.com>
 *
 * Contributors:
 *    Terrence Xu <terrence.xu@intel.com>
 *    Changbin Du <changbin.du@intel.com>
 *    Bing Niu <bing.niu@intel.com>
 *    Zhi Wang <zhi.a.wang@intel.com>
 *
 */

#include "i915_drv.h"
#include "gvt.h"

#define GMBUS1_TOTAL_BYTES_SHIFT 16
#define GMBUS1_TOTAL_BYTES_MASK 0x1ff
#define gmbus1_total_byte_count(v) (((v) >> \
        GMBUS1_TOTAL_BYTES_SHIFT) & GMBUS1_TOTAL_BYTES_MASK)
#define gmbus1_slave_addr(v) (((v) & 0xff) >> 1)
#define gmbus1_slave_index(v) (((v) >> 8) & 0xff)
#define gmbus1_bus_cycle(v) (((v) >> 25) & 0x7)

/* GMBUS0 bits definitions */
#define _GMBUS_PIN_SEL_MASK     (0x7)

static unsigned char edid_get_byte(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_i2c_edid *edid = &vgpu->display.i2c_edid;
        unsigned char chr = 0;

        if (edid->state == I2C_NOT_SPECIFIED || !edid->slave_selected) {
                gvt_vgpu_err("Driver tries to read EDID without proper sequence!\n");
                return 0;
        }
        if (edid->current_edid_read >= EDID_SIZE) {
                gvt_vgpu_err("edid_get_byte() exceeds the size of EDID!\n");
                return 0;
        }

        if (!edid->edid_available) {
                gvt_vgpu_err("Reading EDID but EDID is not available!\n");
                return 0;
        }

        if (intel_vgpu_has_monitor_on_port(vgpu, edid->port)) {
                struct intel_vgpu_edid_data *edid_data =
                        intel_vgpu_port(vgpu, edid->port)->edid;

                chr = edid_data->edid_block[edid->current_edid_read];
                edid->current_edid_read++;
        } else {
                gvt_vgpu_err("No EDID available during the reading?\n");
        }
        return chr;
}

static inline int get_port_from_gmbus0(u32 gmbus0)
{
        int port_select = gmbus0 & _GMBUS_PIN_SEL_MASK;
        int port = -EINVAL;

        if (port_select == 2)
                port = PORT_E;
        else if (port_select == 4)
                port = PORT_C;
        else if (port_select == 5)
                port = PORT_B;
        else if (port_select == 6)
                port = PORT_D;
        return port;
}

static void reset_gmbus_controller(struct intel_vgpu *vgpu)
{
        vgpu_vreg(vgpu, PCH_GMBUS2) = GMBUS_HW_RDY;
        if (!vgpu->display.i2c_edid.edid_available)
                vgpu_vreg(vgpu, PCH_GMBUS2) |= GMBUS_SATOER;
        vgpu->display.i2c_edid.gmbus.phase = GMBUS_IDLE_PHASE;
}

/* GMBUS0 */
static int gmbus0_mmio_write(struct intel_vgpu *vgpu,
                        unsigned int offset, void *p_data, unsigned int bytes)
{
        int port, pin_select;

        memcpy(&vgpu_vreg(vgpu, offset), p_data, bytes);

        pin_select = vgpu_vreg(vgpu, offset) & _GMBUS_PIN_SEL_MASK;

        intel_vgpu_init_i2c_edid(vgpu);

        if (pin_select == 0)
                return 0;

        port = get_port_from_gmbus0(pin_select);
        if (WARN_ON(port < 0))
                return 0;

        vgpu->display.i2c_edid.state = I2C_GMBUS;
        vgpu->display.i2c_edid.gmbus.phase = GMBUS_IDLE_PHASE;

        vgpu_vreg(vgpu, PCH_GMBUS2) &= ~GMBUS_ACTIVE;
        vgpu_vreg(vgpu, PCH_GMBUS2) |= GMBUS_HW_RDY | GMBUS_HW_WAIT_PHASE;

        if (intel_vgpu_has_monitor_on_port(vgpu, port) &&
                        !intel_vgpu_port_is_dp(vgpu, port)) {
                vgpu->display.i2c_edid.port = port;
                vgpu->display.i2c_edid.edid_available = true;
                vgpu_vreg(vgpu, PCH_GMBUS2) &= ~GMBUS_SATOER;
        } else
                vgpu_vreg(vgpu, PCH_GMBUS2) |= GMBUS_SATOER;
        return 0;
}

static int gmbus1_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
                void *p_data, unsigned int bytes)
{
        struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
        u32 slave_addr;
        u32 wvalue = *(u32 *)p_data;

        if (vgpu_vreg(vgpu, offset) & GMBUS_SW_CLR_INT) {
                if (!(wvalue & GMBUS_SW_CLR_INT)) {
                        vgpu_vreg(vgpu, offset) &= ~GMBUS_SW_CLR_INT;
                        reset_gmbus_controller(vgpu);
                }
                /*
                 * TODO: "This bit is cleared to zero when an event
                 * causes the HW_RDY bit transition to occur "
                 */
        } else {
                /*
                 * per bspec setting this bit can cause:
                 * 1) INT status bit cleared
                 * 2) HW_RDY bit asserted
                 */
                if (wvalue & GMBUS_SW_CLR_INT) {
                        vgpu_vreg(vgpu, PCH_GMBUS2) &= ~GMBUS_INT;
                        vgpu_vreg(vgpu, PCH_GMBUS2) |= GMBUS_HW_RDY;
                }

                /* For virtualization, we suppose that HW is always ready,
                 * so GMBUS_SW_RDY should always be cleared
                 */
                if (wvalue & GMBUS_SW_RDY)
                        wvalue &= ~GMBUS_SW_RDY;

                i2c_edid->gmbus.total_byte_count =
                        gmbus1_total_byte_count(wvalue);
                slave_addr = gmbus1_slave_addr(wvalue);

                /* vgpu gmbus only support EDID */
                if (slave_addr == EDID_ADDR) {
                        i2c_edid->slave_selected = true;
                } else if (slave_addr != 0) {
                        gvt_dbg_dpy(
                                "vgpu%d: unsupported gmbus slave addr(0x%x)\n"
                                "       gmbus operations will be ignored.\n",
                                        vgpu->id, slave_addr);
                }

                if (wvalue & GMBUS_CYCLE_INDEX)
                        i2c_edid->current_edid_read =
                                gmbus1_slave_index(wvalue);

                i2c_edid->gmbus.cycle_type = gmbus1_bus_cycle(wvalue);
                switch (gmbus1_bus_cycle(wvalue)) {
                case GMBUS_NOCYCLE:
                        break;
                case GMBUS_STOP:
                        /* From spec:
                         * This can only cause a STOP to be generated
                         * if a GMBUS cycle is generated, the GMBUS is
                         * currently in a data/wait/idle phase, or it is in a
                         * WAIT phase
                         */
                        if (gmbus1_bus_cycle(vgpu_vreg(vgpu, offset))
                                != GMBUS_NOCYCLE) {
                                intel_vgpu_init_i2c_edid(vgpu);
                                /* After the 'stop' cycle, hw state would become
                                 * 'stop phase' and then 'idle phase' after a
                                 * few milliseconds. In emulation, we just set
                                 * it as 'idle phase' ('stop phase' is not
                                 * visible in gmbus interface)
                                 */
                                i2c_edid->gmbus.phase = GMBUS_IDLE_PHASE;
                                vgpu_vreg(vgpu, PCH_GMBUS2) &= ~GMBUS_ACTIVE;
                        }
                        break;
                case NIDX_NS_W:
                case IDX_NS_W:
                case NIDX_STOP:
                case IDX_STOP:
                        /* From hw spec the GMBUS phase
                         * transition like this:
                         * START (-->INDEX) -->DATA
                         */
                        i2c_edid->gmbus.phase = GMBUS_DATA_PHASE;
                        vgpu_vreg(vgpu, PCH_GMBUS2) |= GMBUS_ACTIVE;
                        break;
                default:
                        gvt_vgpu_err("Unknown/reserved GMBUS cycle detected!\n");
                        break;
                }
                /*
                 * From hw spec the WAIT state will be
                 * cleared:
                 * (1) in a new GMBUS cycle
                 * (2) by generating a stop
                 */
                vgpu_vreg(vgpu, offset) = wvalue;
        }
        return 0;
}

static int gmbus3_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
        void *p_data, unsigned int bytes)
{
        WARN_ON(1);
        return 0;
}

static int gmbus3_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
                void *p_data, unsigned int bytes)
{
        int i;
        unsigned char byte_data;
        struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
        int byte_left = i2c_edid->gmbus.total_byte_count -
                                i2c_edid->current_edid_read;
        int byte_count = byte_left;
        u32 reg_data = 0;

        /* Data can only be recevied if previous settings correct */
        if (vgpu_vreg(vgpu, PCH_GMBUS1) & GMBUS_SLAVE_READ) {
                if (byte_left <= 0) {
                        memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
                        return 0;
                }

                if (byte_count > 4)
                        byte_count = 4;
                for (i = 0; i < byte_count; i++) {
                        byte_data = edid_get_byte(vgpu);
                        reg_data |= (byte_data << (i << 3));
                }

                memcpy(&vgpu_vreg(vgpu, offset), &reg_data, byte_count);
                memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);

                if (byte_left <= 4) {
                        switch (i2c_edid->gmbus.cycle_type) {
                        case NIDX_STOP:
                        case IDX_STOP:
                                i2c_edid->gmbus.phase = GMBUS_IDLE_PHASE;
                                break;
                        case NIDX_NS_W:
                        case IDX_NS_W:
                        default:
                                i2c_edid->gmbus.phase = GMBUS_WAIT_PHASE;
                                break;
                        }
                        intel_vgpu_init_i2c_edid(vgpu);
                }
                /*
                 * Read GMBUS3 during send operation,
                 * return the latest written value
                 */
        } else {
                memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
                gvt_vgpu_err("warning: gmbus3 read with nothing returned\n");
        }
        return 0;
}

static int gmbus2_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
                void *p_data, unsigned int bytes)
{
        u32 value = vgpu_vreg(vgpu, offset);

        if (!(vgpu_vreg(vgpu, offset) & GMBUS_INUSE))
                vgpu_vreg(vgpu, offset) |= GMBUS_INUSE;
        memcpy(p_data, (void *)&value, bytes);
        return 0;
}

static int gmbus2_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
                void *p_data, unsigned int bytes)
{
        u32 wvalue = *(u32 *)p_data;

        if (wvalue & GMBUS_INUSE)
                vgpu_vreg(vgpu, offset) &= ~GMBUS_INUSE;
        /* All other bits are read-only */
        return 0;
}

/**
 * intel_gvt_i2c_handle_gmbus_read - emulate gmbus register mmio read
 * @vgpu: a vGPU
 *
 * This function is used to emulate gmbus register mmio read
 *
 * Returns:
 * Zero on success, negative error code if failed.
 *
 */
int intel_gvt_i2c_handle_gmbus_read(struct intel_vgpu *vgpu,
        unsigned int offset, void *p_data, unsigned int bytes)
{
        if (WARN_ON(bytes > 8 && (offset & (bytes - 1))))
                return -EINVAL;

        if (offset == i915_mmio_reg_offset(PCH_GMBUS2))
                return gmbus2_mmio_read(vgpu, offset, p_data, bytes);
        else if (offset == i915_mmio_reg_offset(PCH_GMBUS3))
                return gmbus3_mmio_read(vgpu, offset, p_data, bytes);

        memcpy(p_data, &vgpu_vreg(vgpu, offset), bytes);
        return 0;
}

/**
 * intel_gvt_i2c_handle_gmbus_write - emulate gmbus register mmio write
 * @vgpu: a vGPU
 *
 * This function is used to emulate gmbus register mmio write
 *
 * Returns:
 * Zero on success, negative error code if failed.
 *
 */
int intel_gvt_i2c_handle_gmbus_write(struct intel_vgpu *vgpu,
                unsigned int offset, void *p_data, unsigned int bytes)
{
        if (WARN_ON(bytes > 8 && (offset & (bytes - 1))))
                return -EINVAL;

        if (offset == i915_mmio_reg_offset(PCH_GMBUS0))
                return gmbus0_mmio_write(vgpu, offset, p_data, bytes);
        else if (offset == i915_mmio_reg_offset(PCH_GMBUS1))
                return gmbus1_mmio_write(vgpu, offset, p_data, bytes);
        else if (offset == i915_mmio_reg_offset(PCH_GMBUS2))
                return gmbus2_mmio_write(vgpu, offset, p_data, bytes);
        else if (offset == i915_mmio_reg_offset(PCH_GMBUS3))
                return gmbus3_mmio_write(vgpu, offset, p_data, bytes);

        memcpy(&vgpu_vreg(vgpu, offset), p_data, bytes);
        return 0;
}

enum {
        AUX_CH_CTL = 0,
        AUX_CH_DATA1,
        AUX_CH_DATA2,
        AUX_CH_DATA3,
        AUX_CH_DATA4,
        AUX_CH_DATA5
};

static inline int get_aux_ch_reg(unsigned int offset)
{
        int reg;

        switch (offset & 0xff) {
        case 0x10:
                reg = AUX_CH_CTL;
                break;
        case 0x14:
                reg = AUX_CH_DATA1;
                break;
        case 0x18:
                reg = AUX_CH_DATA2;
                break;
        case 0x1c:
                reg = AUX_CH_DATA3;
                break;
        case 0x20:
                reg = AUX_CH_DATA4;
                break;
        case 0x24:
                reg = AUX_CH_DATA5;
                break;
        default:
                reg = -1;
                break;
        }
        return reg;
}

#define AUX_CTL_MSG_LENGTH(reg) \
        ((reg & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >> \
                DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT)

/**
 * intel_gvt_i2c_handle_aux_ch_write - emulate AUX channel register write
 * @vgpu: a vGPU
 *
 * This function is used to emulate AUX channel register write
 *
 */
void intel_gvt_i2c_handle_aux_ch_write(struct intel_vgpu *vgpu,
                                int port_idx,
                                unsigned int offset,
                                void *p_data)
{
        struct intel_vgpu_i2c_edid *i2c_edid = &vgpu->display.i2c_edid;
        int msg_length, ret_msg_size;
        int msg, addr, ctrl, op;
        u32 value = *(u32 *)p_data;
        int aux_data_for_write = 0;
        int reg = get_aux_ch_reg(offset);

        if (reg != AUX_CH_CTL) {
                vgpu_vreg(vgpu, offset) = value;
                return;
        }

        msg_length = AUX_CTL_MSG_LENGTH(value);
        // check the msg in DATA register.
        msg = vgpu_vreg(vgpu, offset + 4);
        addr = (msg >> 8) & 0xffff;
        ctrl = (msg >> 24) & 0xff;
        op = ctrl >> 4;
        if (!(value & DP_AUX_CH_CTL_SEND_BUSY)) {
                /* The ctl write to clear some states */
                return;
        }

        /* Always set the wanted value for vms. */
        ret_msg_size = (((op & 0x1) == GVT_AUX_I2C_READ) ? 2 : 1);
        vgpu_vreg(vgpu, offset) =
                DP_AUX_CH_CTL_DONE |
                ((ret_msg_size << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) &
                DP_AUX_CH_CTL_MESSAGE_SIZE_MASK);

        if (msg_length == 3) {
                if (!(op & GVT_AUX_I2C_MOT)) {
                        /* stop */
                        intel_vgpu_init_i2c_edid(vgpu);
                } else {
                        /* start or restart */
                        i2c_edid->aux_ch.i2c_over_aux_ch = true;
                        i2c_edid->aux_ch.aux_ch_mot = true;
                        if (addr == 0) {
                                /* reset the address */
                                intel_vgpu_init_i2c_edid(vgpu);
                        } else if (addr == EDID_ADDR) {
                                i2c_edid->state = I2C_AUX_CH;
                                i2c_edid->port = port_idx;
                                i2c_edid->slave_selected = true;
                                if (intel_vgpu_has_monitor_on_port(vgpu,
                                        port_idx) &&
                                        intel_vgpu_port_is_dp(vgpu, port_idx))
                                        i2c_edid->edid_available = true;
                        }
                }
        } else if ((op & 0x1) == GVT_AUX_I2C_WRITE) {
                /* TODO
                 * We only support EDID reading from I2C_over_AUX. And
                 * we do not expect the index mode to be used. Right now
                 * the WRITE operation is ignored. It is good enough to
                 * support the gfx driver to do EDID access.
                 */
        } else {
                if (WARN_ON((op & 0x1) != GVT_AUX_I2C_READ))
                        return;
                if (WARN_ON(msg_length != 4))
                        return;
                if (i2c_edid->edid_available && i2c_edid->slave_selected) {
                        unsigned char val = edid_get_byte(vgpu);

                        aux_data_for_write = (val << 16);
                } else
                        aux_data_for_write = (0xff << 16);
        }
        /* write the return value in AUX_CH_DATA reg which includes:
         * ACK of I2C_WRITE
         * returned byte if it is READ
         */
        aux_data_for_write |= GVT_AUX_I2C_REPLY_ACK << 24;
        vgpu_vreg(vgpu, offset + 4) = aux_data_for_write;
}

/**
 * intel_vgpu_init_i2c_edid - initialize vGPU i2c edid emulation
 * @vgpu: a vGPU
 *
 * This function is used to initialize vGPU i2c edid emulation stuffs
 *
 */
void intel_vgpu_init_i2c_edid(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_i2c_edid *edid = &vgpu->display.i2c_edid;

        edid->state = I2C_NOT_SPECIFIED;

        edid->port = -1;
        edid->slave_selected = false;
        edid->edid_available = false;
        edid->current_edid_read = 0;

        memset(&edid->gmbus, 0, sizeof(struct intel_vgpu_i2c_gmbus));

        edid->aux_ch.i2c_over_aux_ch = false;
        edid->aux_ch.aux_ch_mot = false;
}