// SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
/* Copyright(c) 2021 Intel Corporation */
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include "adf_accel_devices.h"
#include "adf_common_drv.h"
#include "adf_gen2_pfvf.h"
#include "adf_pfvf_msg.h"
#include "adf_pfvf_pf_proto.h"
#include "adf_pfvf_vf_proto.h"
#include "adf_pfvf_utils.h"

 /* VF2PF interrupts */
#define ADF_GEN2_VF_MSK                 0xFFFF
#define ADF_GEN2_ERR_REG_VF2PF(vf_src)  (((vf_src) & 0x01FFFE00) >> 9)
#define ADF_GEN2_ERR_MSK_VF2PF(vf_mask) (((vf_mask) & ADF_GEN2_VF_MSK) << 9)

#define ADF_GEN2_PF_PF2VF_OFFSET(i)     (0x3A000 + 0x280 + ((i) * 0x04))
#define ADF_GEN2_VF_PF2VF_OFFSET        0x200

#define ADF_GEN2_CSR_IN_USE             0x6AC2
#define ADF_GEN2_CSR_IN_USE_MASK        0xFFFE

enum gen2_csr_pos {
        ADF_GEN2_CSR_PF2VF_OFFSET       =  0,
        ADF_GEN2_CSR_VF2PF_OFFSET       = 16,
};

#define ADF_PFVF_GEN2_MSGTYPE_SHIFT     2
#define ADF_PFVF_GEN2_MSGTYPE_MASK      0x0F
#define ADF_PFVF_GEN2_MSGDATA_SHIFT     6
#define ADF_PFVF_GEN2_MSGDATA_MASK      0x3FF

static const struct pfvf_csr_format csr_gen2_fmt = {
        { ADF_PFVF_GEN2_MSGTYPE_SHIFT, ADF_PFVF_GEN2_MSGTYPE_MASK },
        { ADF_PFVF_GEN2_MSGDATA_SHIFT, ADF_PFVF_GEN2_MSGDATA_MASK },
};

#define ADF_PFVF_MSG_RETRY_DELAY        5
#define ADF_PFVF_MSG_MAX_RETRIES        3

static u32 adf_gen2_pf_get_pfvf_offset(u32 i)
{
        return ADF_GEN2_PF_PF2VF_OFFSET(i);
}

static u32 adf_gen2_vf_get_pfvf_offset(u32 i)
{
        return ADF_GEN2_VF_PF2VF_OFFSET;
}

static void adf_gen2_enable_vf2pf_interrupts(void __iomem *pmisc_addr, u32 vf_mask)
{
        /* Enable VF2PF Messaging Ints - VFs 0 through 15 per vf_mask[15:0] */
        if (vf_mask & ADF_GEN2_VF_MSK) {
                u32 val = ADF_CSR_RD(pmisc_addr, ADF_GEN2_ERRMSK3)
                          & ~ADF_GEN2_ERR_MSK_VF2PF(vf_mask);
                ADF_CSR_WR(pmisc_addr, ADF_GEN2_ERRMSK3, val);
        }
}

static void adf_gen2_disable_all_vf2pf_interrupts(void __iomem *pmisc_addr)
{
        /* Disable VF2PF interrupts for VFs 0 through 15 per vf_mask[15:0] */
        u32 val = ADF_CSR_RD(pmisc_addr, ADF_GEN2_ERRMSK3)
                  | ADF_GEN2_ERR_MSK_VF2PF(ADF_GEN2_VF_MSK);
        ADF_CSR_WR(pmisc_addr, ADF_GEN2_ERRMSK3, val);
}

static u32 adf_gen2_disable_pending_vf2pf_interrupts(void __iomem *pmisc_addr)
{
        u32 sources, disabled, pending;
        u32 errsou3, errmsk3;

        /* Get the interrupt sources triggered by VFs */
        errsou3 = ADF_CSR_RD(pmisc_addr, ADF_GEN2_ERRSOU3);
        sources = ADF_GEN2_ERR_REG_VF2PF(errsou3);

        if (!sources)
                return 0;

        /* Get the already disabled interrupts */
        errmsk3 = ADF_CSR_RD(pmisc_addr, ADF_GEN2_ERRMSK3);
        disabled = ADF_GEN2_ERR_REG_VF2PF(errmsk3);

        pending = sources & ~disabled;
        if (!pending)
                return 0;

        /* Due to HW limitations, when disabling the interrupts, we can't
         * just disable the requested sources, as this would lead to missed
         * interrupts if ERRSOU3 changes just before writing to ERRMSK3.
         * To work around it, disable all and re-enable only the sources that
         * are not in vf_mask and were not already disabled. Re-enabling will
         * trigger a new interrupt for the sources that have changed in the
         * meantime, if any.
         */
        errmsk3 |= ADF_GEN2_ERR_MSK_VF2PF(ADF_GEN2_VF_MSK);
        ADF_CSR_WR(pmisc_addr, ADF_GEN2_ERRMSK3, errmsk3);

        /* Update only section of errmsk3 related to VF2PF */
        errmsk3 &= ~ADF_GEN2_ERR_MSK_VF2PF(ADF_GEN2_VF_MSK);
        errmsk3 |= ADF_GEN2_ERR_MSK_VF2PF(sources | disabled);
        ADF_CSR_WR(pmisc_addr, ADF_GEN2_ERRMSK3, errmsk3);

        /* Return the sources of the (new) interrupt(s) */
        return pending;
}

static u32 gen2_csr_get_int_bit(enum gen2_csr_pos offset)
{
        return ADF_PFVF_INT << offset;
}

static u32 gen2_csr_msg_to_position(u32 csr_msg, enum gen2_csr_pos offset)
{
        return (csr_msg & 0xFFFF) << offset;
}

static u32 gen2_csr_msg_from_position(u32 csr_val, enum gen2_csr_pos offset)
{
        return (csr_val >> offset) & 0xFFFF;
}

static bool gen2_csr_is_in_use(u32 msg, enum gen2_csr_pos offset)
{
        return ((msg >> offset) & ADF_GEN2_CSR_IN_USE_MASK) == ADF_GEN2_CSR_IN_USE;
}

static void gen2_csr_clear_in_use(u32 *msg, enum gen2_csr_pos offset)
{
        *msg &= ~(ADF_GEN2_CSR_IN_USE_MASK << offset);
}

static void gen2_csr_set_in_use(u32 *msg, enum gen2_csr_pos offset)
{
        *msg |= (ADF_GEN2_CSR_IN_USE << offset);
}

static bool is_legacy_user_pfvf_message(u32 msg)
{
        return !(msg & ADF_PFVF_MSGORIGIN_SYSTEM);
}

static bool is_pf2vf_notification(u8 msg_type)
{
        switch (msg_type) {
        case ADF_PF2VF_MSGTYPE_RESTARTING:
                return true;
        default:
                return false;
        }
}

static bool is_vf2pf_notification(u8 msg_type)
{
        switch (msg_type) {
        case ADF_VF2PF_MSGTYPE_INIT:
        case ADF_VF2PF_MSGTYPE_SHUTDOWN:
                return true;
        default:
                return false;
        }
}

struct pfvf_gen2_params {
        u32 pfvf_offset;
        struct mutex *csr_lock; /* lock preventing concurrent access of CSR */
        enum gen2_csr_pos local_offset;
        enum gen2_csr_pos remote_offset;
        bool (*is_notification_message)(u8 msg_type);
        u8 compat_ver;
};

static int adf_gen2_pfvf_send(struct adf_accel_dev *accel_dev,
                              struct pfvf_message msg,
                              struct pfvf_gen2_params *params)
{
        void __iomem *pmisc_addr = adf_get_pmisc_base(accel_dev);
        enum gen2_csr_pos remote_offset = params->remote_offset;
        enum gen2_csr_pos local_offset = params->local_offset;
        unsigned int retries = ADF_PFVF_MSG_MAX_RETRIES;
        struct mutex *lock = params->csr_lock;
        u32 pfvf_offset = params->pfvf_offset;
        u32 int_bit;
        u32 csr_val;
        u32 csr_msg;
        int ret;

        /* Gen2 messages, both PF->VF and VF->PF, are all 16 bits long. This
         * allows us to build and read messages as if they where all 0 based.
         * However, send and receive are in a single shared 32 bits register,
         * so we need to shift and/or mask the message half before decoding
         * it and after encoding it. Which one to shift depends on the
         * direction.
         */

        int_bit = gen2_csr_get_int_bit(local_offset);

        csr_msg = adf_pfvf_csr_msg_of(accel_dev, msg, &csr_gen2_fmt);
        if (unlikely(!csr_msg))
                return -EINVAL;

        /* Prepare for CSR format, shifting the wire message in place and
         * setting the in use pattern
         */
        csr_msg = gen2_csr_msg_to_position(csr_msg, local_offset);
        gen2_csr_set_in_use(&csr_msg, remote_offset);

        mutex_lock(lock);

start:
        /* Check if the PFVF CSR is in use by remote function */
        csr_val = ADF_CSR_RD(pmisc_addr, pfvf_offset);
        if (gen2_csr_is_in_use(csr_val, local_offset)) {
                dev_dbg(&GET_DEV(accel_dev),
                        "PFVF CSR in use by remote function\n");
                goto retry;
        }

        /* Attempt to get ownership of the PFVF CSR */
        ADF_CSR_WR(pmisc_addr, pfvf_offset, csr_msg | int_bit);

        /* Wait for confirmation from remote func it received the message */
        ret = read_poll_timeout(ADF_CSR_RD, csr_val, !(csr_val & int_bit),
                                ADF_PFVF_MSG_ACK_DELAY_US,
                                ADF_PFVF_MSG_ACK_MAX_DELAY_US,
                                true, pmisc_addr, pfvf_offset);
        if (unlikely(ret < 0)) {
                dev_dbg(&GET_DEV(accel_dev), "ACK not received from remote\n");
                csr_val &= ~int_bit;
        }

        /* For fire-and-forget notifications, the receiver does not clear
         * the in-use pattern. This is used to detect collisions.
         */
        if (params->is_notification_message(msg.type) && csr_val != csr_msg) {
                /* Collision must have overwritten the message */
                dev_err(&GET_DEV(accel_dev),
                        "Collision on notification - PFVF CSR overwritten by remote function\n");
                goto retry;
        }

        /* If the far side did not clear the in-use pattern it is either
         * 1) Notification - message left intact to detect collision
         * 2) Older protocol (compatibility version < 3) on the far side
         *    where the sender is responsible for clearing the in-use
         *    pattern after the received has acknowledged receipt.
         * In either case, clear the in-use pattern now.
         */
        if (gen2_csr_is_in_use(csr_val, remote_offset)) {
                gen2_csr_clear_in_use(&csr_val, remote_offset);
                ADF_CSR_WR(pmisc_addr, pfvf_offset, csr_val);
        }

out:
        mutex_unlock(lock);
        return ret;

retry:
        if (--retries) {
                msleep(ADF_PFVF_MSG_RETRY_DELAY);
                goto start;
        } else {
                ret = -EBUSY;
                goto out;
        }
}

static struct pfvf_message adf_gen2_pfvf_recv(struct adf_accel_dev *accel_dev,
                                              struct pfvf_gen2_params *params)
{
        void __iomem *pmisc_addr = adf_get_pmisc_base(accel_dev);
        enum gen2_csr_pos remote_offset = params->remote_offset;
        enum gen2_csr_pos local_offset = params->local_offset;
        u32 pfvf_offset = params->pfvf_offset;
        struct pfvf_message msg = { 0 };
        u32 int_bit;
        u32 csr_val;
        u16 csr_msg;

        int_bit = gen2_csr_get_int_bit(local_offset);

        /* Read message */
        csr_val = ADF_CSR_RD(pmisc_addr, pfvf_offset);
        if (!(csr_val & int_bit)) {
                dev_info(&GET_DEV(accel_dev),
                         "Spurious PFVF interrupt, msg 0x%.8x. Ignored\n", csr_val);
                return msg;
        }

        /* Extract the message from the CSR */
        csr_msg = gen2_csr_msg_from_position(csr_val, local_offset);

        /* Ignore legacy non-system (non-kernel) messages */
        if (unlikely(is_legacy_user_pfvf_message(csr_msg))) {
                dev_dbg(&GET_DEV(accel_dev),
                        "Ignored non-system message (0x%.8x);\n", csr_val);
                /* Because this must be a legacy message, the far side
                 * must clear the in-use pattern, so don't do it.
                 */
                return msg;
        }

        /* Return the pfvf_message format */
        msg = adf_pfvf_message_of(accel_dev, csr_msg, &csr_gen2_fmt);

        /* The in-use pattern is not cleared for notifications (so that
         * it can be used for collision detection) or older implementations
         */
        if (params->compat_ver >= ADF_PFVF_COMPAT_FAST_ACK &&
            !params->is_notification_message(msg.type))
                gen2_csr_clear_in_use(&csr_val, remote_offset);

        /* To ACK, clear the INT bit */
        csr_val &= ~int_bit;
        ADF_CSR_WR(pmisc_addr, pfvf_offset, csr_val);

        return msg;
}

static int adf_gen2_pf2vf_send(struct adf_accel_dev *accel_dev, struct pfvf_message msg,
                               u32 pfvf_offset, struct mutex *csr_lock)
{
        struct pfvf_gen2_params params = {
                .csr_lock = csr_lock,
                .pfvf_offset = pfvf_offset,
                .local_offset = ADF_GEN2_CSR_PF2VF_OFFSET,
                .remote_offset = ADF_GEN2_CSR_VF2PF_OFFSET,
                .is_notification_message = is_pf2vf_notification,
        };

        return adf_gen2_pfvf_send(accel_dev, msg, &params);
}

static int adf_gen2_vf2pf_send(struct adf_accel_dev *accel_dev, struct pfvf_message msg,
                               u32 pfvf_offset, struct mutex *csr_lock)
{
        struct pfvf_gen2_params params = {
                .csr_lock = csr_lock,
                .pfvf_offset = pfvf_offset,
                .local_offset = ADF_GEN2_CSR_VF2PF_OFFSET,
                .remote_offset = ADF_GEN2_CSR_PF2VF_OFFSET,
                .is_notification_message = is_vf2pf_notification,
        };

        return adf_gen2_pfvf_send(accel_dev, msg, &params);
}

static struct pfvf_message adf_gen2_pf2vf_recv(struct adf_accel_dev *accel_dev,
                                               u32 pfvf_offset, u8 compat_ver)
{
        struct pfvf_gen2_params params = {
                .pfvf_offset = pfvf_offset,
                .local_offset = ADF_GEN2_CSR_PF2VF_OFFSET,
                .remote_offset = ADF_GEN2_CSR_VF2PF_OFFSET,
                .is_notification_message = is_pf2vf_notification,
                .compat_ver = compat_ver,
        };

        return adf_gen2_pfvf_recv(accel_dev, &params);
}

static struct pfvf_message adf_gen2_vf2pf_recv(struct adf_accel_dev *accel_dev,
                                               u32 pfvf_offset, u8 compat_ver)
{
        struct pfvf_gen2_params params = {
                .pfvf_offset = pfvf_offset,
                .local_offset = ADF_GEN2_CSR_VF2PF_OFFSET,
                .remote_offset = ADF_GEN2_CSR_PF2VF_OFFSET,
                .is_notification_message = is_vf2pf_notification,
                .compat_ver = compat_ver,
        };

        return adf_gen2_pfvf_recv(accel_dev, &params);
}

void adf_gen2_init_pf_pfvf_ops(struct adf_pfvf_ops *pfvf_ops)
{
        pfvf_ops->enable_comms = adf_enable_pf2vf_comms;
        pfvf_ops->get_pf2vf_offset = adf_gen2_pf_get_pfvf_offset;
        pfvf_ops->get_vf2pf_offset = adf_gen2_pf_get_pfvf_offset;
        pfvf_ops->enable_vf2pf_interrupts = adf_gen2_enable_vf2pf_interrupts;
        pfvf_ops->disable_all_vf2pf_interrupts = adf_gen2_disable_all_vf2pf_interrupts;
        pfvf_ops->disable_pending_vf2pf_interrupts = adf_gen2_disable_pending_vf2pf_interrupts;
        pfvf_ops->send_msg = adf_gen2_pf2vf_send;
        pfvf_ops->recv_msg = adf_gen2_vf2pf_recv;
}
EXPORT_SYMBOL_GPL(adf_gen2_init_pf_pfvf_ops);

void adf_gen2_init_vf_pfvf_ops(struct adf_pfvf_ops *pfvf_ops)
{
        pfvf_ops->enable_comms = adf_enable_vf2pf_comms;
        pfvf_ops->get_pf2vf_offset = adf_gen2_vf_get_pfvf_offset;
        pfvf_ops->get_vf2pf_offset = adf_gen2_vf_get_pfvf_offset;
        pfvf_ops->send_msg = adf_gen2_vf2pf_send;
        pfvf_ops->recv_msg = adf_gen2_pf2vf_recv;
}
EXPORT_SYMBOL_GPL(adf_gen2_init_vf_pfvf_ops);