/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright(c) 2015 Intel Deutschland GmbH
 */
#ifndef __DEVCOREDUMP_H
#define __DEVCOREDUMP_H

#include <linux/device.h>
#include <linux/module.h>
#include <linux/vmalloc.h>

#include <linux/scatterlist.h>
#include <linux/slab.h>

/* if data isn't read by userspace after 5 minutes then delete it */
#define DEVCD_TIMEOUT   (HZ * 60 * 5)

/*
 * _devcd_free_sgtable - free all the memory of the given scatterlist table
 * (i.e. both pages and scatterlist instances)
 * NOTE: if two tables allocated and chained using the sg_chain function then
 * this function should be called only once on the first table
 * @table: pointer to sg_table to free
 */
static inline void _devcd_free_sgtable(struct scatterlist *table)
{
        int i;
        struct page *page;
        struct scatterlist *iter;
        struct scatterlist *delete_iter;

        /* free pages */
        iter = table;
        for_each_sg(table, iter, sg_nents(table), i) {
                page = sg_page(iter);
                if (page)
                        __free_page(page);
        }

        /* then free all chained tables */
        iter = table;
        delete_iter = table;    /* always points on a head of a table */
        while (!sg_is_last(iter)) {
                iter++;
                if (sg_is_chain(iter)) {
                        iter = sg_chain_ptr(iter);
                        kfree(delete_iter);
                        delete_iter = iter;
                }
        }

        /* free the last table */
        kfree(delete_iter);
}

#ifdef CONFIG_DEV_COREDUMP
void dev_coredumpv(struct device *dev, void *data, size_t datalen,
                   gfp_t gfp);

void dev_coredumpm_timeout(struct device *dev, struct module *owner,
                           void *data, size_t datalen, gfp_t gfp,
                           ssize_t (*read)(char *buffer, loff_t offset,
                                           size_t count, void *data,
                                           size_t datalen),
                           void (*free)(void *data),
                           unsigned long timeout);

void dev_coredumpsg(struct device *dev, struct scatterlist *table,
                    size_t datalen, gfp_t gfp);

void dev_coredump_put(struct device *dev);
#else
static inline void dev_coredumpv(struct device *dev, void *data,
                                 size_t datalen, gfp_t gfp)
{
        vfree(data);
}

static inline void
dev_coredumpm_timeout(struct device *dev, struct module *owner,
                      void *data, size_t datalen, gfp_t gfp,
                      ssize_t (*read)(char *buffer, loff_t offset,
                                      size_t count, void *data,
                                      size_t datalen),
                      void (*free)(void *data),
                      unsigned long timeout)
{
        free(data);
}

static inline void dev_coredumpsg(struct device *dev, struct scatterlist *table,
                                  size_t datalen, gfp_t gfp)
{
        _devcd_free_sgtable(table);
}
static inline void dev_coredump_put(struct device *dev)
{
}
#endif /* CONFIG_DEV_COREDUMP */

/**
 * dev_coredumpm - create device coredump with read/free methods
 * @dev: the struct device for the crashed device
 * @owner: the module that contains the read/free functions, use %THIS_MODULE
 * @data: data cookie for the @read/@free functions
 * @datalen: length of the data
 * @gfp: allocation flags
 * @read: function to read from the given buffer
 * @free: function to free the given buffer
 *
 * Creates a new device coredump for the given device. If a previous one hasn't
 * been read yet, the new coredump is discarded. The data lifetime is determined
 * by the device coredump framework and when it is no longer needed the @free
 * function will be called to free the data.
 */
static inline void dev_coredumpm(struct device *dev, struct module *owner,
                                 void *data, size_t datalen, gfp_t gfp,
                                 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
                                                 void *data, size_t datalen),
                                void (*free)(void *data))
{
        dev_coredumpm_timeout(dev, owner, data, datalen, gfp, read, free,
                              DEVCD_TIMEOUT);
}

#endif /* __DEVCOREDUMP_H */