// SPDX-License-Identifier: GPL-2.0+

#include "fdma_api.h"

#include <linux/bits.h>
#include <linux/etherdevice.h>
#include <linux/types.h>

/* Add a DB to a DCB, providing a callback for getting the DB dataptr. */
static int __fdma_db_add(struct fdma *fdma, int dcb_idx, int db_idx, u64 status,
                         int (*cb)(struct fdma *fdma, int dcb_idx,
                                   int db_idx, u64 *dataptr))
{
        struct fdma_db *db = fdma_db_get(fdma, dcb_idx, db_idx);

        db->status = status;

        return cb(fdma, dcb_idx, db_idx, &db->dataptr);
}

/* Add a DB to a DCB, using the callback set in the fdma_ops struct. */
int fdma_db_add(struct fdma *fdma, int dcb_idx, int db_idx, u64 status)
{
        return __fdma_db_add(fdma,
                             dcb_idx,
                             db_idx,
                             status,
                             fdma->ops.dataptr_cb);
}

/* Add a DCB with callbacks for getting the DB dataptr and the DCB nextptr. */
int __fdma_dcb_add(struct fdma *fdma, int dcb_idx, u64 info, u64 status,
                   int (*dcb_cb)(struct fdma *fdma, int dcb_idx, u64 *nextptr),
                   int (*db_cb)(struct fdma *fdma, int dcb_idx, int db_idx,
                                u64 *dataptr))
{
        struct fdma_dcb *dcb = fdma_dcb_get(fdma, dcb_idx);
        int i, err;

        for (i = 0; i < fdma->n_dbs; i++) {
                err = __fdma_db_add(fdma, dcb_idx, i, status, db_cb);
                if (unlikely(err))
                        return err;
        }

        err = dcb_cb(fdma, dcb_idx, &fdma->last_dcb->nextptr);
        if (unlikely(err))
                return err;

        fdma->last_dcb = dcb;

        dcb->nextptr = FDMA_DCB_INVALID_DATA;
        dcb->info = info;

        return 0;
}
EXPORT_SYMBOL_GPL(__fdma_dcb_add);

/* Add a DCB, using the preset callbacks in the fdma_ops struct. */
int fdma_dcb_add(struct fdma *fdma, int dcb_idx, u64 info, u64 status)
{
        return __fdma_dcb_add(fdma,
                              dcb_idx,
                              info, status,
                              fdma->ops.nextptr_cb,
                              fdma->ops.dataptr_cb);
}
EXPORT_SYMBOL_GPL(fdma_dcb_add);

/* Initialize the DCB's and DB's. */
int fdma_dcbs_init(struct fdma *fdma, u64 info, u64 status)
{
        int i, err;

        fdma->last_dcb = fdma->dcbs;
        fdma->db_index = 0;
        fdma->dcb_index = 0;

        for (i = 0; i < fdma->n_dcbs; i++) {
                err = fdma_dcb_add(fdma, i, info, status);
                if (err)
                        return err;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(fdma_dcbs_init);

/* Allocate coherent DMA memory for FDMA. */
int fdma_alloc_coherent(struct device *dev, struct fdma *fdma)
{
        fdma->dcbs = dma_alloc_coherent(dev,
                                        fdma->size,
                                        &fdma->dma,
                                        GFP_KERNEL);
        if (!fdma->dcbs)
                return -ENOMEM;

        return 0;
}
EXPORT_SYMBOL_GPL(fdma_alloc_coherent);

/* Allocate physical memory for FDMA. */
int fdma_alloc_phys(struct fdma *fdma)
{
        fdma->dcbs = kzalloc(fdma->size, GFP_KERNEL);
        if (!fdma->dcbs)
                return -ENOMEM;

        fdma->dma = virt_to_phys(fdma->dcbs);

        return 0;
}
EXPORT_SYMBOL_GPL(fdma_alloc_phys);

/* Free coherent DMA memory. */
void fdma_free_coherent(struct device *dev, struct fdma *fdma)
{
        dma_free_coherent(dev, fdma->size, fdma->dcbs, fdma->dma);
}
EXPORT_SYMBOL_GPL(fdma_free_coherent);

/* Free virtual memory. */
void fdma_free_phys(struct fdma *fdma)
{
        kfree(fdma->dcbs);
}
EXPORT_SYMBOL_GPL(fdma_free_phys);

/* Get the size of the FDMA memory */
u32 fdma_get_size(struct fdma *fdma)
{
        return ALIGN(sizeof(struct fdma_dcb) * fdma->n_dcbs, PAGE_SIZE);
}
EXPORT_SYMBOL_GPL(fdma_get_size);

/* Get the size of the FDMA memory. This function is only applicable if the
 * dataptr addresses and DCB's are in contiguous memory.
 */
u32 fdma_get_size_contiguous(struct fdma *fdma)
{
        return ALIGN(fdma->n_dcbs * sizeof(struct fdma_dcb) +
                     fdma->n_dcbs * fdma->n_dbs * fdma->db_size,
                     PAGE_SIZE);
}
EXPORT_SYMBOL_GPL(fdma_get_size_contiguous);