// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2024
 *
 * Author(s):
 *   Niklas Schnelle <schnelle@linux.ibm.com>
 *
 */

#define pr_fmt(fmt) "zpci: " fmt

#include <linux/kernel.h>
#include <linux/sprintf.h>
#include <linux/pci.h>

#include <asm/sclp.h>
#include <asm/debug.h>
#include <asm/pci_debug.h>

#include "pci_report.h"

#define ZPCI_ERR_LOG_ID_KERNEL_REPORT 0x4714

struct zpci_report_error_data {
        u64 timestamp;
        u64 err_log_id;
        char log_data[];
} __packed;

#define ZPCI_REPORT_SIZE        (PAGE_SIZE - sizeof(struct err_notify_sccb))
#define ZPCI_REPORT_DATA_SIZE   (ZPCI_REPORT_SIZE - sizeof(struct zpci_report_error_data))

struct zpci_report_error {
        struct zpci_report_error_header header;
        struct zpci_report_error_data data;
} __packed;

static const char *zpci_state_str(pci_channel_state_t state)
{
        switch (state) {
        case pci_channel_io_normal:
                return "normal";
        case pci_channel_io_frozen:
                return "frozen";
        case pci_channel_io_perm_failure:
                return "permanent-failure";
        default:
                return "invalid";
        };
}

static int debug_log_header_fn(debug_info_t *id, struct debug_view *view,
                               int area, debug_entry_t *entry, char *out_buf,
                               size_t out_buf_size)
{
        unsigned long sec, usec;
        unsigned int level;
        char *except_str;
        int rc = 0;

        level = entry->level;
        sec = entry->clock;
        usec = do_div(sec, USEC_PER_SEC);

        if (entry->exception)
                except_str = "*";
        else
                except_str = "-";
        rc += scnprintf(out_buf, out_buf_size, "%011ld:%06lu %1u %1s %04u  ",
                        sec, usec, level, except_str,
                        entry->cpu);
        return rc;
}

static int debug_prolog_header(debug_info_t *id, struct debug_view *view,
                               char *out_buf, size_t out_buf_size)
{
        return scnprintf(out_buf, out_buf_size, "sec:usec level except cpu  msg\n");
}

static struct debug_view debug_log_view = {
        "pci_msg_log",
        &debug_prolog_header,
        &debug_log_header_fn,
        &debug_sprintf_format_fn,
        NULL,
        NULL
};

/**
 * zpci_report_status - Report the status of operations on a PCI device
 * @zdev:       The PCI device for which to report status
 * @operation:  A string representing the operation reported
 * @status:     A string representing the status of the operation
 *
 * This function creates a human readable report about an operation such as
 * PCI device recovery and forwards this to the platform using the SCLP Write
 * Event Data mechanism. Besides the operation and status strings the report
 * also contains additional information about the device deemed useful for
 * debug such as the currently bound device driver, if any, and error state.
 * Additionally a string representation of pci_debug_msg_id, or as much as fits,
 * is also included.
 *
 * Return: 0 on success an error code < 0 otherwise.
 */
int zpci_report_status(struct zpci_dev *zdev, const char *operation, const char *status)
{
        struct zpci_report_error *report;
        struct pci_driver *driver = NULL;
        struct pci_dev *pdev = NULL;
        char *buf, *end;
        int ret;

        if (!zdev || !zdev->zbus)
                return -ENODEV;

        /* Protected virtualization hosts get nothing from us */
        if (prot_virt_guest)
                return -ENODATA;

        report = (void *)get_zeroed_page(GFP_KERNEL);
        if (!report)
                return -ENOMEM;
        if (zdev->zbus->bus)
                pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
        if (pdev)
                driver = to_pci_driver(pdev->dev.driver);

        buf = report->data.log_data;
        end = report->data.log_data + ZPCI_REPORT_DATA_SIZE;
        buf += scnprintf(buf, end - buf, "report: %s\n", operation);
        buf += scnprintf(buf, end - buf, "status: %s\n", status);
        buf += scnprintf(buf, end - buf, "state: %s\n",
                         (pdev) ? zpci_state_str(pdev->error_state) : "n/a");
        buf += scnprintf(buf, end - buf, "driver: %s\n", (driver) ? driver->name : "n/a");
        ret = debug_dump(pci_debug_msg_id, &debug_log_view, buf, end - buf, true);
        if (ret < 0)
                pr_err("Reading PCI debug messages failed with code %d\n", ret);
        else
                buf += ret;

        report->header.version = 1;
        report->header.action = SCLP_ERRNOTIFY_AQ_INFO_LOG;
        report->header.length = buf - (char *)&report->data;
        report->data.timestamp = ktime_get_clocktai_seconds();
        report->data.err_log_id = ZPCI_ERR_LOG_ID_KERNEL_REPORT;

        ret = sclp_pci_report(&report->header, zdev->fh, zdev->fid);
        if (ret)
                pr_err("Reporting PCI status failed with code %d\n", ret);
        else
                pr_info("Reported PCI device status\n");

        free_page((unsigned long)report);

        return ret;
}