// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
 *  Copyright (c) by Scott McNab <sdm@fractalgraphics.com.au>
 *
 *  Trident 4DWave-NX memory page allocation (TLB area)
 *  Trident chip can handle only 16MByte of the memory at the same time.
 */

#include <linux/io.h>
#include <linux/pci.h>
#include <linux/time.h>
#include <linux/mutex.h>

#include <sound/core.h>
#include "trident.h"

/* page arguments of these two macros are Trident page (4096 bytes), not like
 * aligned pages in others
 */
#define __set_tlb_bus(trident,page,addr) \
        (trident)->tlb.entries[page] = cpu_to_le32((addr) & ~(SNDRV_TRIDENT_PAGE_SIZE-1))
#define __tlb_to_addr(trident,page) \
        (dma_addr_t)le32_to_cpu((trident->tlb.entries[page]) & ~(SNDRV_TRIDENT_PAGE_SIZE - 1))

#if PAGE_SIZE == 4096
/* page size == SNDRV_TRIDENT_PAGE_SIZE */
#define ALIGN_PAGE_SIZE         PAGE_SIZE       /* minimum page size for allocation */
#define MAX_ALIGN_PAGES         SNDRV_TRIDENT_MAX_PAGES /* maxmium aligned pages */
/* fill TLB entrie(s) corresponding to page with ptr */
#define set_tlb_bus(trident,page,addr) __set_tlb_bus(trident,page,addr)
/* fill TLB entrie(s) corresponding to page with silence pointer */
#define set_silent_tlb(trident,page)    __set_tlb_bus(trident, page, trident->tlb.silent_page->addr)
/* get aligned page from offset address */
#define get_aligned_page(offset)        ((offset) >> 12)
/* get offset address from aligned page */
#define aligned_page_offset(page)       ((page) << 12)
/* get PCI physical address from aligned page */
#define page_to_addr(trident,page)      __tlb_to_addr(trident, page)

#elif PAGE_SIZE == 8192
/* page size == SNDRV_TRIDENT_PAGE_SIZE x 2*/
#define ALIGN_PAGE_SIZE         PAGE_SIZE
#define MAX_ALIGN_PAGES         (SNDRV_TRIDENT_MAX_PAGES / 2)
#define get_aligned_page(offset)        ((offset) >> 13)
#define aligned_page_offset(page)       ((page) << 13)
#define page_to_addr(trident,page)      __tlb_to_addr(trident, (page) << 1)

/* fill TLB entries -- we need to fill two entries */
static inline void set_tlb_bus(struct snd_trident *trident, int page,
                               dma_addr_t addr)
{
        page <<= 1;
        __set_tlb_bus(trident, page, addr);
        __set_tlb_bus(trident, page+1, addr + SNDRV_TRIDENT_PAGE_SIZE);
}
static inline void set_silent_tlb(struct snd_trident *trident, int page)
{
        page <<= 1;
        __set_tlb_bus(trident, page, trident->tlb.silent_page->addr);
        __set_tlb_bus(trident, page+1, trident->tlb.silent_page->addr);
}

#else
/* arbitrary size */
#define UNIT_PAGES              (PAGE_SIZE / SNDRV_TRIDENT_PAGE_SIZE)
#define ALIGN_PAGE_SIZE         (SNDRV_TRIDENT_PAGE_SIZE * UNIT_PAGES)
#define MAX_ALIGN_PAGES         (SNDRV_TRIDENT_MAX_PAGES / UNIT_PAGES)
/* Note: if alignment doesn't match to the maximum size, the last few blocks
 * become unusable.  To use such blocks, you'll need to check the validity
 * of accessing page in set_tlb_bus and set_silent_tlb.  search_empty()
 * should also check it, too.
 */
#define get_aligned_page(offset)        ((offset) / ALIGN_PAGE_SIZE)
#define aligned_page_offset(page)       ((page) * ALIGN_PAGE_SIZE)
#define page_to_addr(trident,page)      __tlb_to_addr(trident, (page) * UNIT_PAGES)

/* fill TLB entries -- UNIT_PAGES entries must be filled */
static inline void set_tlb_bus(struct snd_trident *trident, int page,
                               dma_addr_t addr)
{
        int i;
        page *= UNIT_PAGES;
        for (i = 0; i < UNIT_PAGES; i++, page++) {
                __set_tlb_bus(trident, page, addr);
                addr += SNDRV_TRIDENT_PAGE_SIZE;
        }
}
static inline void set_silent_tlb(struct snd_trident *trident, int page)
{
        int i;
        page *= UNIT_PAGES;
        for (i = 0; i < UNIT_PAGES; i++, page++)
                __set_tlb_bus(trident, page, trident->tlb.silent_page->addr);
}

#endif /* PAGE_SIZE */

/* first and last (aligned) pages of memory block */
#define firstpg(blk)    (((struct snd_trident_memblk_arg *)snd_util_memblk_argptr(blk))->first_page)
#define lastpg(blk)     (((struct snd_trident_memblk_arg *)snd_util_memblk_argptr(blk))->last_page)

/*
 * search empty pages which may contain given size
 */
static struct snd_util_memblk *
search_empty(struct snd_util_memhdr *hdr, int size)
{
        struct snd_util_memblk *blk;
        int page, psize;
        struct list_head *p;

        psize = get_aligned_page(size + ALIGN_PAGE_SIZE -1);
        page = 0;
        list_for_each(p, &hdr->block) {
                blk = list_entry(p, struct snd_util_memblk, list);
                if (page + psize <= firstpg(blk))
                        goto __found_pages;
                page = lastpg(blk) + 1;
        }
        if (page + psize > MAX_ALIGN_PAGES)
                return NULL;

__found_pages:
        /* create a new memory block */
        blk = __snd_util_memblk_new(hdr, psize * ALIGN_PAGE_SIZE, p->prev);
        if (blk == NULL)
                return NULL;
        blk->offset = aligned_page_offset(page); /* set aligned offset */
        firstpg(blk) = page;
        lastpg(blk) = page + psize - 1;
        return blk;
}


/*
 * check if the given pointer is valid for pages
 */
static int is_valid_page(struct snd_trident *trident, unsigned long ptr)
{
        if (ptr & ~0x3fffffffUL) {
                dev_err(trident->card->dev, "max memory size is 1GB!!\n");
                return 0;
        }
        if (ptr & (SNDRV_TRIDENT_PAGE_SIZE-1)) {
                dev_err(trident->card->dev, "page is not aligned\n");
                return 0;
        }
        return 1;
}

/*
 * page allocation for DMA (Scatter-Gather version)
 */
static struct snd_util_memblk *
snd_trident_alloc_sg_pages(struct snd_trident *trident,
                           struct snd_pcm_substream *substream)
{
        struct snd_util_memhdr *hdr;
        struct snd_util_memblk *blk;
        struct snd_pcm_runtime *runtime = substream->runtime;
        int idx, page;

        if (snd_BUG_ON(runtime->dma_bytes <= 0 ||
                       runtime->dma_bytes > SNDRV_TRIDENT_MAX_PAGES *
                                        SNDRV_TRIDENT_PAGE_SIZE))
                return NULL;
        hdr = trident->tlb.memhdr;
        if (snd_BUG_ON(!hdr))
                return NULL;

        

        guard(mutex)(&hdr->block_mutex);
        blk = search_empty(hdr, runtime->dma_bytes);
        if (blk == NULL)
                return NULL;
                           
        /* set TLB entries */
        idx = 0;
        for (page = firstpg(blk); page <= lastpg(blk); page++, idx++) {
                unsigned long ofs = idx << PAGE_SHIFT;
                dma_addr_t addr = snd_pcm_sgbuf_get_addr(substream, ofs);
                if (!is_valid_page(trident, addr)) {
                        __snd_util_mem_free(hdr, blk);
                        return NULL;
                }
                set_tlb_bus(trident, page, addr);
        }
        return blk;
}

/*
 * page allocation for DMA (contiguous version)
 */
static struct snd_util_memblk *
snd_trident_alloc_cont_pages(struct snd_trident *trident,
                             struct snd_pcm_substream *substream)
{
        struct snd_util_memhdr *hdr;
        struct snd_util_memblk *blk;
        int page;
        struct snd_pcm_runtime *runtime = substream->runtime;
        dma_addr_t addr;

        if (snd_BUG_ON(runtime->dma_bytes <= 0 ||
                       runtime->dma_bytes > SNDRV_TRIDENT_MAX_PAGES *
                                        SNDRV_TRIDENT_PAGE_SIZE))
                return NULL;
        hdr = trident->tlb.memhdr;
        if (snd_BUG_ON(!hdr))
                return NULL;

        guard(mutex)(&hdr->block_mutex);
        blk = search_empty(hdr, runtime->dma_bytes);
        if (blk == NULL)
                return NULL;
                           
        /* set TLB entries */
        addr = runtime->dma_addr;
        for (page = firstpg(blk); page <= lastpg(blk); page++,
             addr += SNDRV_TRIDENT_PAGE_SIZE) {
                if (!is_valid_page(trident, addr)) {
                        __snd_util_mem_free(hdr, blk);
                        return NULL;
                }
                set_tlb_bus(trident, page, addr);
        }
        return blk;
}

/*
 * page allocation for DMA
 */
struct snd_util_memblk *
snd_trident_alloc_pages(struct snd_trident *trident,
                        struct snd_pcm_substream *substream)
{
        if (snd_BUG_ON(!trident || !substream))
                return NULL;
        if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV_SG)
                return snd_trident_alloc_sg_pages(trident, substream);
        else
                return snd_trident_alloc_cont_pages(trident, substream);
}


/*
 * release DMA buffer from page table
 */
int snd_trident_free_pages(struct snd_trident *trident,
                           struct snd_util_memblk *blk)
{
        struct snd_util_memhdr *hdr;
        int page;

        if (snd_BUG_ON(!trident || !blk))
                return -EINVAL;

        hdr = trident->tlb.memhdr;
        guard(mutex)(&hdr->block_mutex);
        /* reset TLB entries */
        for (page = firstpg(blk); page <= lastpg(blk); page++)
                set_silent_tlb(trident, page);
        /* free memory block */
        __snd_util_mem_free(hdr, blk);
        return 0;
}