// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
#include <linux/unaligned.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sizes.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/aer.h>
#include <linux/io.h>
#include <cxl/mailbox.h>
#include "cxlmem.h"
#include "cxlpci.h"
#include "cxl.h"
#include "pmu.h"

/**
 * DOC: cxl pci
 *
 * This implements the PCI exclusive functionality for a CXL device as it is
 * defined by the Compute Express Link specification. CXL devices may surface
 * certain functionality even if it isn't CXL enabled. While this driver is
 * focused around the PCI specific aspects of a CXL device, it binds to the
 * specific CXL memory device class code, and therefore the implementation of
 * cxl_pci is focused around CXL memory devices.
 *
 * The driver has several responsibilities, mainly:
 *  - Create the memX device and register on the CXL bus.
 *  - Enumerate device's register interface and map them.
 *  - Registers nvdimm bridge device with cxl_core.
 *  - Registers a CXL mailbox with cxl_core.
 */

#define cxl_doorbell_busy(cxlds)                                                \
        (readl((cxlds)->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET) &                  \
         CXLDEV_MBOX_CTRL_DOORBELL)

/* CXL 2.0 - 8.2.8.4 */
#define CXL_MAILBOX_TIMEOUT_MS (2 * HZ)

/*
 * CXL 2.0 ECN "Add Mailbox Ready Time" defines a capability field to
 * dictate how long to wait for the mailbox to become ready. The new
 * field allows the device to tell software the amount of time to wait
 * before mailbox ready. This field per the spec theoretically allows
 * for up to 255 seconds. 255 seconds is unreasonably long, its longer
 * than the maximum SATA port link recovery wait. Default to 60 seconds
 * until someone builds a CXL device that needs more time in practice.
 */
static unsigned short mbox_ready_timeout = 60;
module_param(mbox_ready_timeout, ushort, 0644);
MODULE_PARM_DESC(mbox_ready_timeout, "seconds to wait for mailbox ready");

static int cxl_pci_mbox_wait_for_doorbell(struct cxl_dev_state *cxlds)
{
        const unsigned long start = jiffies;
        unsigned long end = start;

        while (cxl_doorbell_busy(cxlds)) {
                end = jiffies;

                if (time_after(end, start + CXL_MAILBOX_TIMEOUT_MS)) {
                        /* Check again in case preempted before timeout test */
                        if (!cxl_doorbell_busy(cxlds))
                                break;
                        return -ETIMEDOUT;
                }
                cpu_relax();
        }

        dev_dbg(cxlds->dev, "Doorbell wait took %dms",
                jiffies_to_msecs(end) - jiffies_to_msecs(start));
        return 0;
}

#define cxl_err(dev, status, msg)                                        \
        dev_err_ratelimited(dev, msg ", device state %s%s\n",                  \
                            status & CXLMDEV_DEV_FATAL ? " fatal" : "",        \
                            status & CXLMDEV_FW_HALT ? " firmware-halt" : "")

#define cxl_cmd_err(dev, cmd, status, msg)                               \
        dev_err_ratelimited(dev, msg " (opcode: %#x), device state %s%s\n",    \
                            (cmd)->opcode,                                     \
                            status & CXLMDEV_DEV_FATAL ? " fatal" : "",        \
                            status & CXLMDEV_FW_HALT ? " firmware-halt" : "")

/*
 * Threaded irq dev_id's must be globally unique.  cxl_dev_id provides a unique
 * wrapper object for each irq within the same cxlds.
 */
struct cxl_dev_id {
        struct cxl_dev_state *cxlds;
};

static int cxl_request_irq(struct cxl_dev_state *cxlds, int irq,
                           irq_handler_t thread_fn)
{
        struct device *dev = cxlds->dev;
        struct cxl_dev_id *dev_id;

        dev_id = devm_kzalloc(dev, sizeof(*dev_id), GFP_KERNEL);
        if (!dev_id)
                return -ENOMEM;
        dev_id->cxlds = cxlds;

        return devm_request_threaded_irq(dev, irq, NULL, thread_fn,
                                         IRQF_SHARED | IRQF_ONESHOT, NULL,
                                         dev_id);
}

static bool cxl_mbox_background_complete(struct cxl_dev_state *cxlds)
{
        u64 reg;

        reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
        return FIELD_GET(CXLDEV_MBOX_BG_CMD_COMMAND_PCT_MASK, reg) == 100;
}

static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
{
        u64 reg;
        u16 opcode;
        struct cxl_dev_id *dev_id = id;
        struct cxl_dev_state *cxlds = dev_id->cxlds;
        struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);

        if (!cxl_mbox_background_complete(cxlds))
                return IRQ_NONE;

        reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
        opcode = FIELD_GET(CXLDEV_MBOX_BG_CMD_COMMAND_OPCODE_MASK, reg);
        if (opcode == CXL_MBOX_OP_SANITIZE) {
                mutex_lock(&cxl_mbox->mbox_mutex);
                if (mds->security.sanitize_node)
                        mod_delayed_work(system_percpu_wq, &mds->security.poll_dwork, 0);
                mutex_unlock(&cxl_mbox->mbox_mutex);
        } else {
                /* short-circuit the wait in __cxl_pci_mbox_send_cmd() */
                rcuwait_wake_up(&cxl_mbox->mbox_wait);
        }

        return IRQ_HANDLED;
}

/*
 * Sanitization operation polling mode.
 */
static void cxl_mbox_sanitize_work(struct work_struct *work)
{
        struct cxl_memdev_state *mds =
                container_of(work, typeof(*mds), security.poll_dwork.work);
        struct cxl_dev_state *cxlds = &mds->cxlds;
        struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;

        mutex_lock(&cxl_mbox->mbox_mutex);
        if (cxl_mbox_background_complete(cxlds)) {
                mds->security.poll_tmo_secs = 0;
                if (mds->security.sanitize_node)
                        sysfs_notify_dirent(mds->security.sanitize_node);
                mds->security.sanitize_active = false;

                dev_dbg(cxlds->dev, "Sanitization operation ended\n");
        } else {
                int timeout = mds->security.poll_tmo_secs + 10;

                mds->security.poll_tmo_secs = min(15 * 60, timeout);
                schedule_delayed_work(&mds->security.poll_dwork, timeout * HZ);
        }
        mutex_unlock(&cxl_mbox->mbox_mutex);
}

/**
 * __cxl_pci_mbox_send_cmd() - Execute a mailbox command
 * @cxl_mbox: CXL mailbox context
 * @mbox_cmd: Command to send to the memory device.
 *
 * Context: Any context. Expects mbox_mutex to be held.
 * Return: -ETIMEDOUT if timeout occurred waiting for completion. 0 on success.
 *         Caller should check the return code in @mbox_cmd to make sure it
 *         succeeded.
 *
 * This is a generic form of the CXL mailbox send command thus only using the
 * registers defined by the mailbox capability ID - CXL 2.0 8.2.8.4. Memory
 * devices, and perhaps other types of CXL devices may have further information
 * available upon error conditions. Driver facilities wishing to send mailbox
 * commands should use the wrapper command.
 *
 * The CXL spec allows for up to two mailboxes. The intention is for the primary
 * mailbox to be OS controlled and the secondary mailbox to be used by system
 * firmware. This allows the OS and firmware to communicate with the device and
 * not need to coordinate with each other. The driver only uses the primary
 * mailbox.
 */
static int __cxl_pci_mbox_send_cmd(struct cxl_mailbox *cxl_mbox,
                                   struct cxl_mbox_cmd *mbox_cmd)
{
        struct cxl_dev_state *cxlds = mbox_to_cxlds(cxl_mbox);
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
        void __iomem *payload = cxlds->regs.mbox + CXLDEV_MBOX_PAYLOAD_OFFSET;
        struct device *dev = cxlds->dev;
        u64 cmd_reg, status_reg;
        size_t out_len;
        int rc;

        lockdep_assert_held(&cxl_mbox->mbox_mutex);

        /*
         * Here are the steps from 8.2.8.4 of the CXL 2.0 spec.
         *   1. Caller reads MB Control Register to verify doorbell is clear
         *   2. Caller writes Command Register
         *   3. Caller writes Command Payload Registers if input payload is non-empty
         *   4. Caller writes MB Control Register to set doorbell
         *   5. Caller either polls for doorbell to be clear or waits for interrupt if configured
         *   6. Caller reads MB Status Register to fetch Return code
         *   7. If command successful, Caller reads Command Register to get Payload Length
         *   8. If output payload is non-empty, host reads Command Payload Registers
         *
         * Hardware is free to do whatever it wants before the doorbell is rung,
         * and isn't allowed to change anything after it clears the doorbell. As
         * such, steps 2 and 3 can happen in any order, and steps 6, 7, 8 can
         * also happen in any order (though some orders might not make sense).
         */

        /* #1 */
        if (cxl_doorbell_busy(cxlds)) {
                u64 md_status =
                        readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);

                cxl_cmd_err(cxlds->dev, mbox_cmd, md_status,
                            "mailbox queue busy");
                return -EBUSY;
        }

        /*
         * With sanitize polling, hardware might be done and the poller still
         * not be in sync. Ensure no new command comes in until so. Keep the
         * hardware semantics and only allow device health status.
         */
        if (mds->security.poll_tmo_secs > 0) {
                if (mbox_cmd->opcode != CXL_MBOX_OP_GET_HEALTH_INFO)
                        return -EBUSY;
        }

        cmd_reg = FIELD_PREP(CXLDEV_MBOX_CMD_COMMAND_OPCODE_MASK,
                             mbox_cmd->opcode);
        if (mbox_cmd->size_in) {
                if (WARN_ON(!mbox_cmd->payload_in))
                        return -EINVAL;

                cmd_reg |= FIELD_PREP(CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK,
                                      mbox_cmd->size_in);
                memcpy_toio(payload, mbox_cmd->payload_in, mbox_cmd->size_in);
        }

        /* #2, #3 */
        writeq(cmd_reg, cxlds->regs.mbox + CXLDEV_MBOX_CMD_OFFSET);

        /* #4 */
        dev_dbg(dev, "Sending command: 0x%04x\n", mbox_cmd->opcode);
        writel(CXLDEV_MBOX_CTRL_DOORBELL,
               cxlds->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET);

        /* #5 */
        rc = cxl_pci_mbox_wait_for_doorbell(cxlds);
        if (rc == -ETIMEDOUT) {
                u64 md_status = readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);

                cxl_cmd_err(cxlds->dev, mbox_cmd, md_status, "mailbox timeout");
                return rc;
        }

        /* #6 */
        status_reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_STATUS_OFFSET);
        mbox_cmd->return_code =
                FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);

        /*
         * Handle the background command in a synchronous manner.
         *
         * All other mailbox commands will serialize/queue on the mbox_mutex,
         * which we currently hold. Furthermore this also guarantees that
         * cxl_mbox_background_complete() checks are safe amongst each other,
         * in that no new bg operation can occur in between.
         *
         * Background operations are timesliced in accordance with the nature
         * of the command. In the event of timeout, the mailbox state is
         * indeterminate until the next successful command submission and the
         * driver can get back in sync with the hardware state.
         */
        if (mbox_cmd->return_code == CXL_MBOX_CMD_RC_BACKGROUND) {
                u64 bg_status_reg;
                int i, timeout;

                /*
                 * Sanitization is a special case which monopolizes the device
                 * and cannot be timesliced. Handle asynchronously instead,
                 * and allow userspace to poll(2) for completion.
                 */
                if (mbox_cmd->opcode == CXL_MBOX_OP_SANITIZE) {
                        if (mds->security.sanitize_active)
                                return -EBUSY;

                        /* give first timeout a second */
                        timeout = 1;
                        mds->security.poll_tmo_secs = timeout;
                        mds->security.sanitize_active = true;
                        schedule_delayed_work(&mds->security.poll_dwork,
                                              timeout * HZ);
                        dev_dbg(dev, "Sanitization operation started\n");
                        goto success;
                }

                dev_dbg(dev, "Mailbox background operation (0x%04x) started\n",
                        mbox_cmd->opcode);

                timeout = mbox_cmd->poll_interval_ms;
                for (i = 0; i < mbox_cmd->poll_count; i++) {
                        if (rcuwait_wait_event_timeout(&cxl_mbox->mbox_wait,
                                                       cxl_mbox_background_complete(cxlds),
                                                       TASK_UNINTERRUPTIBLE,
                                                       msecs_to_jiffies(timeout)) > 0)
                                break;
                }

                if (!cxl_mbox_background_complete(cxlds)) {
                        dev_err(dev, "timeout waiting for background (%d ms)\n",
                                timeout * mbox_cmd->poll_count);
                        return -ETIMEDOUT;
                }

                bg_status_reg = readq(cxlds->regs.mbox +
                                      CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
                mbox_cmd->return_code =
                        FIELD_GET(CXLDEV_MBOX_BG_CMD_COMMAND_RC_MASK,
                                  bg_status_reg);
                dev_dbg(dev,
                        "Mailbox background operation (0x%04x) completed\n",
                        mbox_cmd->opcode);
        }

        if (mbox_cmd->return_code != CXL_MBOX_CMD_RC_SUCCESS) {
                dev_dbg(dev, "Mailbox operation had an error: %s\n",
                        cxl_mbox_cmd_rc2str(mbox_cmd));
                return 0; /* completed but caller must check return_code */
        }

success:
        /* #7 */
        cmd_reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_CMD_OFFSET);
        out_len = FIELD_GET(CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK, cmd_reg);

        /* #8 */
        if (out_len && mbox_cmd->payload_out) {
                /*
                 * Sanitize the copy. If hardware misbehaves, out_len per the
                 * spec can actually be greater than the max allowed size (21
                 * bits available but spec defined 1M max). The caller also may
                 * have requested less data than the hardware supplied even
                 * within spec.
                 */
                size_t n;

                n = min3(mbox_cmd->size_out, cxl_mbox->payload_size, out_len);
                memcpy_fromio(mbox_cmd->payload_out, payload, n);
                mbox_cmd->size_out = n;
        } else {
                mbox_cmd->size_out = 0;
        }

        return 0;
}

static int cxl_pci_mbox_send(struct cxl_mailbox *cxl_mbox,
                             struct cxl_mbox_cmd *cmd)
{
        int rc;

        mutex_lock(&cxl_mbox->mbox_mutex);
        rc = __cxl_pci_mbox_send_cmd(cxl_mbox, cmd);
        mutex_unlock(&cxl_mbox->mbox_mutex);

        return rc;
}

static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
{
        struct cxl_dev_state *cxlds = &mds->cxlds;
        struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
        const int cap = readl(cxlds->regs.mbox + CXLDEV_MBOX_CAPS_OFFSET);
        struct device *dev = cxlds->dev;
        unsigned long timeout;
        int irq, msgnum;
        u64 md_status;
        u32 ctrl;

        timeout = jiffies + mbox_ready_timeout * HZ;
        do {
                md_status = readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);
                if (md_status & CXLMDEV_MBOX_IF_READY)
                        break;
                if (msleep_interruptible(100))
                        break;
        } while (!time_after(jiffies, timeout));

        if (!(md_status & CXLMDEV_MBOX_IF_READY)) {
                cxl_err(dev, md_status, "timeout awaiting mailbox ready");
                return -ETIMEDOUT;
        }

        /*
         * A command may be in flight from a previous driver instance,
         * think kexec, do one doorbell wait so that
         * __cxl_pci_mbox_send_cmd() can assume that it is the only
         * source for future doorbell busy events.
         */
        if (cxl_pci_mbox_wait_for_doorbell(cxlds) != 0) {
                cxl_err(dev, md_status, "timeout awaiting mailbox idle");
                return -ETIMEDOUT;
        }

        cxl_mbox->mbox_send = cxl_pci_mbox_send;
        cxl_mbox->payload_size =
                1 << FIELD_GET(CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK, cap);

        /*
         * CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register
         *
         * If the size is too small, mandatory commands will not work and so
         * there's no point in going forward. If the size is too large, there's
         * no harm is soft limiting it.
         */
        cxl_mbox->payload_size = min_t(size_t, cxl_mbox->payload_size, SZ_1M);
        if (cxl_mbox->payload_size < 256) {
                dev_err(dev, "Mailbox is too small (%zub)",
                        cxl_mbox->payload_size);
                return -ENXIO;
        }

        dev_dbg(dev, "Mailbox payload sized %zu", cxl_mbox->payload_size);

        INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mbox_sanitize_work);

        /* background command interrupts are optional */
        if (!(cap & CXLDEV_MBOX_CAP_BG_CMD_IRQ) || !irq_avail)
                return 0;

        msgnum = FIELD_GET(CXLDEV_MBOX_CAP_IRQ_MSGNUM_MASK, cap);
        irq = pci_irq_vector(to_pci_dev(cxlds->dev), msgnum);
        if (irq < 0)
                return 0;

        if (cxl_request_irq(cxlds, irq, cxl_pci_mbox_irq))
                return 0;

        dev_dbg(cxlds->dev, "Mailbox interrupts enabled\n");
        /* enable background command mbox irq support */
        ctrl = readl(cxlds->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET);
        ctrl |= CXLDEV_MBOX_CTRL_BG_CMD_IRQ;
        writel(ctrl, cxlds->regs.mbox + CXLDEV_MBOX_CTRL_OFFSET);

        return 0;
}

/*
 * Assume that any RCIEP that emits the CXL memory expander class code
 * is an RCD
 */
static bool is_cxl_restricted(struct pci_dev *pdev)
{
        return pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END;
}

static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
                                  struct cxl_register_map *map,
                                  struct cxl_dport *dport)
{
        resource_size_t component_reg_phys;

        *map = (struct cxl_register_map) {
                .host = &pdev->dev,
                .resource = CXL_RESOURCE_NONE,
        };

        struct cxl_port *port __free(put_cxl_port) =
                cxl_pci_find_port(pdev, &dport);
        if (!port)
                return -EPROBE_DEFER;

        component_reg_phys = cxl_rcd_component_reg_phys(&pdev->dev, dport);
        if (component_reg_phys == CXL_RESOURCE_NONE)
                return -ENXIO;

        map->resource = component_reg_phys;
        map->reg_type = CXL_REGLOC_RBI_COMPONENT;
        map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;

        return 0;
}

static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
                              struct cxl_register_map *map)
{
        int rc;

        rc = cxl_find_regblock(pdev, type, map);

        /*
         * If the Register Locator DVSEC does not exist, check if it
         * is an RCH and try to extract the Component Registers from
         * an RCRB.
         */
        if (rc && type == CXL_REGLOC_RBI_COMPONENT && is_cxl_restricted(pdev)) {
                struct cxl_dport *dport;
                struct cxl_port *port __free(put_cxl_port) =
                        cxl_pci_find_port(pdev, &dport);
                if (!port)
                        return -EPROBE_DEFER;

                rc = cxl_rcrb_get_comp_regs(pdev, map, dport);
                if (rc)
                        return rc;

                rc = cxl_dport_map_rcd_linkcap(pdev, dport);
                if (rc)
                        return rc;

        } else if (rc) {
                return rc;
        }

        return cxl_setup_regs(map);
}

static void free_event_buf(void *buf)
{
        kvfree(buf);
}

/*
 * There is a single buffer for reading event logs from the mailbox.  All logs
 * share this buffer protected by the mds->event_log_lock.
 */
static int cxl_mem_alloc_event_buf(struct cxl_memdev_state *mds)
{
        struct cxl_mailbox *cxl_mbox = &mds->cxlds.cxl_mbox;
        struct cxl_get_event_payload *buf;

        buf = kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;
        mds->event.buf = buf;

        return devm_add_action_or_reset(mds->cxlds.dev, free_event_buf, buf);
}

static bool cxl_alloc_irq_vectors(struct pci_dev *pdev)
{
        int nvecs;

        /*
         * Per CXL 3.0 3.1.1 CXL.io Endpoint a function on a CXL device must
         * not generate INTx messages if that function participates in
         * CXL.cache or CXL.mem.
         *
         * Additionally pci_alloc_irq_vectors() handles calling
         * pci_free_irq_vectors() automatically despite not being called
         * pcim_*.  See pci_setup_msi_context().
         */
        nvecs = pci_alloc_irq_vectors(pdev, 1, CXL_PCI_DEFAULT_MAX_VECTORS,
                                      PCI_IRQ_MSIX | PCI_IRQ_MSI);
        if (nvecs < 1) {
                dev_dbg(&pdev->dev, "Failed to alloc irq vectors: %d\n", nvecs);
                return false;
        }
        return true;
}

static irqreturn_t cxl_event_thread(int irq, void *id)
{
        struct cxl_dev_id *dev_id = id;
        struct cxl_dev_state *cxlds = dev_id->cxlds;
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
        u32 status;

        do {
                /*
                 * CXL 3.0 8.2.8.3.1: The lower 32 bits are the status;
                 * ignore the reserved upper 32 bits
                 */
                status = readl(cxlds->regs.status + CXLDEV_DEV_EVENT_STATUS_OFFSET);
                /* Ignore logs unknown to the driver */
                status &= CXLDEV_EVENT_STATUS_ALL;
                if (!status)
                        break;
                cxl_mem_get_event_records(mds, status);
                cond_resched();
        } while (status);

        return IRQ_HANDLED;
}

static int cxl_event_req_irq(struct cxl_dev_state *cxlds, u8 setting)
{
        struct pci_dev *pdev = to_pci_dev(cxlds->dev);
        int irq;

        if (FIELD_GET(CXLDEV_EVENT_INT_MODE_MASK, setting) != CXL_INT_MSI_MSIX)
                return -ENXIO;

        irq =  pci_irq_vector(pdev,
                              FIELD_GET(CXLDEV_EVENT_INT_MSGNUM_MASK, setting));
        if (irq < 0)
                return irq;

        return cxl_request_irq(cxlds, irq, cxl_event_thread);
}

static int cxl_event_get_int_policy(struct cxl_memdev_state *mds,
                                    struct cxl_event_interrupt_policy *policy)
{
        struct cxl_mailbox *cxl_mbox = &mds->cxlds.cxl_mbox;
        struct cxl_mbox_cmd mbox_cmd = {
                .opcode = CXL_MBOX_OP_GET_EVT_INT_POLICY,
                .payload_out = policy,
                .size_out = sizeof(*policy),
        };
        int rc;

        rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
        if (rc < 0)
                dev_err(mds->cxlds.dev,
                        "Failed to get event interrupt policy : %d", rc);

        return rc;
}

static int cxl_event_config_msgnums(struct cxl_memdev_state *mds,
                                    struct cxl_event_interrupt_policy *policy)
{
        struct cxl_mailbox *cxl_mbox = &mds->cxlds.cxl_mbox;
        struct cxl_mbox_cmd mbox_cmd;
        int rc;

        *policy = (struct cxl_event_interrupt_policy) {
                .info_settings = CXL_INT_MSI_MSIX,
                .warn_settings = CXL_INT_MSI_MSIX,
                .failure_settings = CXL_INT_MSI_MSIX,
                .fatal_settings = CXL_INT_MSI_MSIX,
        };

        mbox_cmd = (struct cxl_mbox_cmd) {
                .opcode = CXL_MBOX_OP_SET_EVT_INT_POLICY,
                .payload_in = policy,
                .size_in = sizeof(*policy),
        };

        rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
        if (rc < 0) {
                dev_err(mds->cxlds.dev, "Failed to set event interrupt policy : %d",
                        rc);
                return rc;
        }

        /* Retrieve final interrupt settings */
        return cxl_event_get_int_policy(mds, policy);
}

static int cxl_event_irqsetup(struct cxl_memdev_state *mds)
{
        struct cxl_dev_state *cxlds = &mds->cxlds;
        struct cxl_event_interrupt_policy policy;
        int rc;

        rc = cxl_event_config_msgnums(mds, &policy);
        if (rc)
                return rc;

        rc = cxl_event_req_irq(cxlds, policy.info_settings);
        if (rc) {
                dev_err(cxlds->dev, "Failed to get interrupt for event Info log\n");
                return rc;
        }

        rc = cxl_event_req_irq(cxlds, policy.warn_settings);
        if (rc) {
                dev_err(cxlds->dev, "Failed to get interrupt for event Warn log\n");
                return rc;
        }

        rc = cxl_event_req_irq(cxlds, policy.failure_settings);
        if (rc) {
                dev_err(cxlds->dev, "Failed to get interrupt for event Failure log\n");
                return rc;
        }

        rc = cxl_event_req_irq(cxlds, policy.fatal_settings);
        if (rc) {
                dev_err(cxlds->dev, "Failed to get interrupt for event Fatal log\n");
                return rc;
        }

        return 0;
}

static bool cxl_event_int_is_fw(u8 setting)
{
        u8 mode = FIELD_GET(CXLDEV_EVENT_INT_MODE_MASK, setting);

        return mode == CXL_INT_FW;
}

static int cxl_event_config(struct pci_host_bridge *host_bridge,
                            struct cxl_memdev_state *mds, bool irq_avail)
{
        struct cxl_event_interrupt_policy policy;
        int rc;

        /*
         * When BIOS maintains CXL error reporting control, it will process
         * event records.  Only one agent can do so.
         */
        if (!host_bridge->native_cxl_error)
                return 0;

        if (!irq_avail) {
                dev_info(mds->cxlds.dev, "No interrupt support, disable event processing.\n");
                return 0;
        }

        rc = cxl_event_get_int_policy(mds, &policy);
        if (rc)
                return rc;

        if (cxl_event_int_is_fw(policy.info_settings) ||
            cxl_event_int_is_fw(policy.warn_settings) ||
            cxl_event_int_is_fw(policy.failure_settings) ||
            cxl_event_int_is_fw(policy.fatal_settings)) {
                dev_err(mds->cxlds.dev,
                        "FW still in control of Event Logs despite _OSC settings\n");
                return -EBUSY;
        }

        rc = cxl_mem_alloc_event_buf(mds);
        if (rc)
                return rc;

        rc = cxl_event_irqsetup(mds);
        if (rc)
                return rc;

        cxl_mem_get_event_records(mds, CXLDEV_EVENT_STATUS_ALL);

        return 0;
}

static int cxl_pci_type3_init_mailbox(struct cxl_dev_state *cxlds)
{
        int rc;

        /*
         * Fail the init if there's no mailbox. For a type3 this is out of spec.
         */
        if (!cxlds->reg_map.device_map.mbox.valid)
                return -ENODEV;

        rc = cxl_mailbox_init(&cxlds->cxl_mbox, cxlds->dev);
        if (rc)
                return rc;

        return 0;
}

static ssize_t rcd_pcie_cap_emit(struct device *dev, u16 offset, char *buf, size_t width)
{
        struct cxl_dev_state *cxlds = dev_get_drvdata(dev);
        struct cxl_memdev *cxlmd = cxlds->cxlmd;
        struct device *root_dev;
        struct cxl_dport *dport;
        struct cxl_port *root __free(put_cxl_port) =
                cxl_mem_find_port(cxlmd, &dport);

        if (!root)
                return -ENXIO;

        root_dev = root->uport_dev;
        if (!root_dev)
                return -ENXIO;

        if (!dport->regs.rcd_pcie_cap)
                return -ENXIO;

        guard(device)(root_dev);
        if (!root_dev->driver)
                return -ENXIO;

        switch (width) {
        case 2:
                return sysfs_emit(buf, "%#x\n",
                                  readw(dport->regs.rcd_pcie_cap + offset));
        case 4:
                return sysfs_emit(buf, "%#x\n",
                                  readl(dport->regs.rcd_pcie_cap + offset));
        default:
                return -EINVAL;
        }
}

static ssize_t rcd_link_cap_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return rcd_pcie_cap_emit(dev, PCI_EXP_LNKCAP, buf, sizeof(u32));
}
static DEVICE_ATTR_RO(rcd_link_cap);

static ssize_t rcd_link_ctrl_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        return rcd_pcie_cap_emit(dev, PCI_EXP_LNKCTL, buf, sizeof(u16));
}
static DEVICE_ATTR_RO(rcd_link_ctrl);

static ssize_t rcd_link_status_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        return rcd_pcie_cap_emit(dev, PCI_EXP_LNKSTA, buf, sizeof(u16));
}
static DEVICE_ATTR_RO(rcd_link_status);

static struct attribute *cxl_rcd_attrs[] = {
        &dev_attr_rcd_link_cap.attr,
        &dev_attr_rcd_link_ctrl.attr,
        &dev_attr_rcd_link_status.attr,
        NULL
};

static umode_t cxl_rcd_visible(struct kobject *kobj, struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (is_cxl_restricted(pdev))
                return a->mode;

        return 0;
}

static struct attribute_group cxl_rcd_group = {
        .attrs = cxl_rcd_attrs,
        .is_visible = cxl_rcd_visible,
};
__ATTRIBUTE_GROUPS(cxl_rcd);

static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
        struct cxl_dpa_info range_info = { 0 };
        struct cxl_memdev_state *mds;
        struct cxl_dev_state *cxlds;
        struct cxl_register_map map;
        struct cxl_memdev *cxlmd;
        int rc, pmu_count;
        unsigned int i;
        bool irq_avail;

        rc = pcim_enable_device(pdev);
        if (rc)
                return rc;
        pci_set_master(pdev);

        mds = cxl_memdev_state_create(&pdev->dev);
        if (IS_ERR(mds))
                return PTR_ERR(mds);
        cxlds = &mds->cxlds;
        pci_set_drvdata(pdev, cxlds);

        cxlds->rcd = is_cxl_restricted(pdev);
        cxlds->serial = pci_get_dsn(pdev);
        cxlds->cxl_dvsec = pci_find_dvsec_capability(
                pdev, PCI_VENDOR_ID_CXL, PCI_DVSEC_CXL_DEVICE);
        if (!cxlds->cxl_dvsec)
                dev_warn(&pdev->dev,
                         "Device DVSEC not present, skip CXL.mem init\n");

        rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
        if (rc)
                return rc;

        rc = cxl_map_device_regs(&map, &cxlds->regs);
        if (rc)
                return rc;

        /*
         * If the component registers can't be found, the cxl_pci driver may
         * still be useful for management functions so don't return an error.
         */
        rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
                                &cxlds->reg_map);
        if (rc)
                dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
        else if (!cxlds->reg_map.component_map.ras.valid)
                dev_dbg(&pdev->dev, "RAS registers not found\n");

        rc = cxl_pci_type3_init_mailbox(cxlds);
        if (rc)
                return rc;

        rc = cxl_await_media_ready(cxlds);
        if (rc == 0)
                cxlds->media_ready = true;
        else
                dev_warn(&pdev->dev, "Media not active (%d)\n", rc);

        irq_avail = cxl_alloc_irq_vectors(pdev);

        rc = cxl_pci_setup_mailbox(mds, irq_avail);
        if (rc)
                return rc;

        rc = cxl_enumerate_cmds(mds);
        if (rc)
                return rc;

        rc = cxl_set_timestamp(mds);
        if (rc)
                return rc;

        rc = cxl_poison_state_init(mds);
        if (rc)
                return rc;

        rc = cxl_dev_state_identify(mds);
        if (rc)
                return rc;

        rc = cxl_mem_dpa_fetch(mds, &range_info);
        if (rc)
                return rc;

        rc = cxl_dpa_setup(cxlds, &range_info);
        if (rc)
                return rc;

        rc = devm_cxl_setup_features(cxlds);
        if (rc)
                dev_dbg(&pdev->dev, "No CXL Features discovered\n");

        cxlmd = devm_cxl_add_memdev(cxlds, NULL);
        if (IS_ERR(cxlmd))
                return PTR_ERR(cxlmd);

        rc = devm_cxl_setup_fw_upload(&pdev->dev, mds);
        if (rc)
                return rc;

        rc = devm_cxl_sanitize_setup_notifier(&pdev->dev, cxlmd);
        if (rc)
                return rc;

        rc = devm_cxl_setup_fwctl(&pdev->dev, cxlmd);
        if (rc)
                dev_dbg(&pdev->dev, "No CXL FWCTL setup\n");

        pmu_count = cxl_count_regblock(pdev, CXL_REGLOC_RBI_PMU);
        if (pmu_count < 0)
                return pmu_count;

        for (i = 0; i < pmu_count; i++) {
                struct cxl_pmu_regs pmu_regs;

                rc = cxl_find_regblock_instance(pdev, CXL_REGLOC_RBI_PMU, &map, i);
                if (rc) {
                        dev_dbg(&pdev->dev, "Could not find PMU regblock\n");
                        break;
                }

                rc = cxl_map_pmu_regs(&map, &pmu_regs);
                if (rc) {
                        dev_dbg(&pdev->dev, "Could not map PMU regs\n");
                        break;
                }

                rc = devm_cxl_pmu_add(cxlds->dev, &pmu_regs, cxlmd->id, i, CXL_PMU_MEMDEV);
                if (rc) {
                        dev_dbg(&pdev->dev, "Could not add PMU instance\n");
                        break;
                }
        }

        rc = cxl_event_config(host_bridge, mds, irq_avail);
        if (rc)
                return rc;

        pci_save_state(pdev);

        return rc;
}

static const struct pci_device_id cxl_mem_pci_tbl[] = {
        /* PCI class code for CXL.mem Type-3 Devices */
        { PCI_DEVICE_CLASS((PCI_CLASS_MEMORY_CXL << 8 | CXL_MEMORY_PROGIF), ~0)},
        { /* terminate list */ },
};
MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl);

static pci_ers_result_t cxl_slot_reset(struct pci_dev *pdev)
{
        struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
        struct cxl_memdev *cxlmd = cxlds->cxlmd;
        struct device *dev = &cxlmd->dev;

        dev_info(&pdev->dev, "%s: restart CXL.mem after slot reset\n",
                 dev_name(dev));
        pci_restore_state(pdev);
        if (device_attach(dev) <= 0)
                return PCI_ERS_RESULT_DISCONNECT;
        return PCI_ERS_RESULT_RECOVERED;
}

static void cxl_error_resume(struct pci_dev *pdev)
{
        struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
        struct cxl_memdev *cxlmd = cxlds->cxlmd;
        struct device *dev = &cxlmd->dev;

        dev_info(&pdev->dev, "%s: error resume %s\n", dev_name(dev),
                 dev->driver ? "successful" : "failed");
}

static void cxl_reset_done(struct pci_dev *pdev)
{
        struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
        struct cxl_memdev *cxlmd = cxlds->cxlmd;
        struct device *dev = &pdev->dev;

        /*
         * FLR does not expect to touch the HDM decoders and related
         * registers.  SBR, however, will wipe all device configurations.
         * Issue a warning if there was an active decoder before the reset
         * that no longer exists.
         */
        guard(device)(&cxlmd->dev);
        if (cxlmd->endpoint &&
            cxl_endpoint_decoder_reset_detected(cxlmd->endpoint)) {
                dev_crit(dev, "SBR happened without memory regions removal.\n");
                dev_crit(dev, "System may be unstable if regions hosted system memory.\n");
                add_taint(TAINT_USER, LOCKDEP_STILL_OK);
        }
}

static const struct pci_error_handlers cxl_error_handlers = {
        .error_detected = cxl_error_detected,
        .slot_reset     = cxl_slot_reset,
        .resume         = cxl_error_resume,
        .cor_error_detected     = cxl_cor_error_detected,
        .reset_done     = cxl_reset_done,
};

static struct pci_driver cxl_pci_driver = {
        .name                   = KBUILD_MODNAME,
        .id_table               = cxl_mem_pci_tbl,
        .probe                  = cxl_pci_probe,
        .err_handler            = &cxl_error_handlers,
        .dev_groups             = cxl_rcd_groups,
        .driver = {
                .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
        },
};

#define CXL_EVENT_HDR_FLAGS_REC_SEVERITY GENMASK(1, 0)
static void cxl_handle_cper_event(enum cxl_event_type ev_type,
                                  struct cxl_cper_event_rec *rec)
{
        struct cper_cxl_event_devid *device_id = &rec->hdr.device_id;
        struct pci_dev *pdev __free(pci_dev_put) = NULL;
        enum cxl_event_log_type log_type;
        struct cxl_dev_state *cxlds;
        unsigned int devfn;
        u32 hdr_flags;

        pr_debug("CPER event %d for device %u:%u:%u.%u\n", ev_type,
                 device_id->segment_num, device_id->bus_num,
                 device_id->device_num, device_id->func_num);

        devfn = PCI_DEVFN(device_id->device_num, device_id->func_num);
        pdev = pci_get_domain_bus_and_slot(device_id->segment_num,
                                           device_id->bus_num, devfn);
        if (!pdev)
                return;

        guard(device)(&pdev->dev);
        if (pdev->driver != &cxl_pci_driver)
                return;

        cxlds = pci_get_drvdata(pdev);
        if (!cxlds)
                return;

        /* Fabricate a log type */
        hdr_flags = get_unaligned_le24(rec->event.generic.hdr.flags);
        log_type = FIELD_GET(CXL_EVENT_HDR_FLAGS_REC_SEVERITY, hdr_flags);

        cxl_event_trace_record(cxlds->cxlmd, log_type, ev_type,
                               &uuid_null, &rec->event);
}

static void cxl_cper_work_fn(struct work_struct *work)
{
        struct cxl_cper_work_data wd;

        while (cxl_cper_kfifo_get(&wd))
                cxl_handle_cper_event(wd.event_type, &wd.rec);
}
static DECLARE_WORK(cxl_cper_work, cxl_cper_work_fn);

static int __init cxl_pci_driver_init(void)
{
        int rc;

        rc = pci_register_driver(&cxl_pci_driver);
        if (rc)
                return rc;

        rc = cxl_cper_register_work(&cxl_cper_work);
        if (rc)
                pci_unregister_driver(&cxl_pci_driver);

        return rc;
}

static void __exit cxl_pci_driver_exit(void)
{
        cxl_cper_unregister_work(&cxl_cper_work);
        cancel_work_sync(&cxl_cper_work);
        pci_unregister_driver(&cxl_pci_driver);
}

module_init(cxl_pci_driver_init);
module_exit(cxl_pci_driver_exit);
MODULE_DESCRIPTION("CXL: PCI manageability");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("CXL");