// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
 *
 *  EMU10K1 memory page allocation (PTB area)
 */

#include <linux/pci.h>
#include <linux/gfp.h>
#include <linux/time.h>
#include <linux/mutex.h>
#include <linux/export.h>

#include <sound/core.h>
#include <sound/emu10k1.h>

/* page arguments of these two macros are Emu page (4096 bytes), not like
 * aligned pages in others
 */
#define __set_ptb_entry(emu,page,addr) \
        (((__le32 *)(emu)->ptb_pages.area)[page] = \
         cpu_to_le32(((addr) << (emu->address_mode)) | (page)))
#define __get_ptb_entry(emu, page) \
        (le32_to_cpu(((__le32 *)(emu)->ptb_pages.area)[page]))

#define UNIT_PAGES              (PAGE_SIZE / EMUPAGESIZE)
#define MAX_ALIGN_PAGES0                (MAXPAGES0 / UNIT_PAGES)
#define MAX_ALIGN_PAGES1                (MAXPAGES1 / UNIT_PAGES)
/* get aligned page from offset address */
#define get_aligned_page(offset)        ((offset) >> PAGE_SHIFT)
/* get offset address from aligned page */
#define aligned_page_offset(page)       ((page) << PAGE_SHIFT)

#if PAGE_SIZE == EMUPAGESIZE && !IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
/* fill PTB entrie(s) corresponding to page with addr */
#define set_ptb_entry(emu,page,addr)    __set_ptb_entry(emu,page,addr)
/* fill PTB entrie(s) corresponding to page with silence pointer */
#define set_silent_ptb(emu,page)        __set_ptb_entry(emu,page,emu->silent_page.addr)
#else
/* fill PTB entries -- we need to fill UNIT_PAGES entries */
static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
{
        int i;
        page *= UNIT_PAGES;
        for (i = 0; i < UNIT_PAGES; i++, page++) {
                __set_ptb_entry(emu, page, addr);
                dev_dbg(emu->card->dev, "mapped page %d to entry %.8x\n", page,
                        (unsigned int)__get_ptb_entry(emu, page));
                addr += EMUPAGESIZE;
        }
}
static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
{
        int i;
        page *= UNIT_PAGES;
        for (i = 0; i < UNIT_PAGES; i++, page++) {
                /* do not increment ptr */
                __set_ptb_entry(emu, page, emu->silent_page.addr);
                dev_dbg(emu->card->dev, "mapped silent page %d to entry %.8x\n",
                        page, (unsigned int)__get_ptb_entry(emu, page));
        }
}
#endif /* PAGE_SIZE */


/*
 */
static int synth_alloc_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
static int synth_free_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);

#define get_emu10k1_memblk(l,member)    list_entry(l, struct snd_emu10k1_memblk, member)


/* initialize emu10k1 part */
static void emu10k1_memblk_init(struct snd_emu10k1_memblk *blk)
{
        blk->mapped_page = -1;
        INIT_LIST_HEAD(&blk->mapped_link);
        INIT_LIST_HEAD(&blk->mapped_order_link);
        blk->map_locked = 0;

        blk->first_page = get_aligned_page(blk->mem.offset);
        blk->last_page = get_aligned_page(blk->mem.offset + blk->mem.size - 1);
        blk->pages = blk->last_page - blk->first_page + 1;
}

/*
 * search empty region on PTB with the given size
 *
 * if an empty region is found, return the page and store the next mapped block
 * in nextp
 * if not found, return a negative error code.
 */
static int search_empty_map_area(struct snd_emu10k1 *emu, int npages, struct list_head **nextp)
{
        int page = 1, found_page = -ENOMEM;
        int max_size = npages;
        int size;
        struct list_head *candidate = &emu->mapped_link_head;
        struct list_head *pos;

        list_for_each (pos, &emu->mapped_link_head) {
                struct snd_emu10k1_memblk *blk = get_emu10k1_memblk(pos, mapped_link);
                if (blk->mapped_page < 0)
                        continue;
                size = blk->mapped_page - page;
                if (size == npages) {
                        *nextp = pos;
                        return page;
                }
                else if (size > max_size) {
                        /* we look for the maximum empty hole */
                        max_size = size;
                        candidate = pos;
                        found_page = page;
                }
                page = blk->mapped_page + blk->pages;
        }
        size = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0) - page;
        if (size >= max_size) {
                *nextp = pos;
                return page;
        }
        *nextp = candidate;
        return found_page;
}

/*
 * map a memory block onto emu10k1's PTB
 *
 * call with memblk_lock held
 */
static int map_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
        int page, pg;
        struct list_head *next;

        page = search_empty_map_area(emu, blk->pages, &next);
        if (page < 0) /* not found */
                return page;
        if (page == 0) {
                dev_err(emu->card->dev, "trying to map zero (reserved) page\n");
                return -EINVAL;
        }
        /* insert this block in the proper position of mapped list */
        list_add_tail(&blk->mapped_link, next);
        /* append this as a newest block in order list */
        list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
        blk->mapped_page = page;
        /* fill PTB */
        for (pg = blk->first_page; pg <= blk->last_page; pg++) {
                set_ptb_entry(emu, page, emu->page_addr_table[pg]);
                page++;
        }
        return 0;
}

/*
 * unmap the block
 * return the size of resultant empty pages
 *
 * call with memblk_lock held
 */
static int unmap_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
        int start_page, end_page, mpage, pg;
        struct list_head *p;
        struct snd_emu10k1_memblk *q;

        /* calculate the expected size of empty region */
        p = blk->mapped_link.prev;
        if (p != &emu->mapped_link_head) {
                q = get_emu10k1_memblk(p, mapped_link);
                start_page = q->mapped_page + q->pages;
        } else {
                start_page = 1;
        }
        p = blk->mapped_link.next;
        if (p != &emu->mapped_link_head) {
                q = get_emu10k1_memblk(p, mapped_link);
                end_page = q->mapped_page;
        } else {
                end_page = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0);
        }

        /* remove links */
        list_del(&blk->mapped_link);
        list_del(&blk->mapped_order_link);
        /* clear PTB */
        mpage = blk->mapped_page;
        for (pg = blk->first_page; pg <= blk->last_page; pg++) {
                set_silent_ptb(emu, mpage);
                mpage++;
        }
        blk->mapped_page = -1;
        return end_page - start_page; /* return the new empty size */
}

/*
 * search empty pages with the given size, and create a memory block
 *
 * unlike synth_alloc the memory block is aligned to the page start
 */
static struct snd_emu10k1_memblk *
search_empty(struct snd_emu10k1 *emu, int size)
{
        struct list_head *p;
        struct snd_emu10k1_memblk *blk;
        int page, psize;

        psize = get_aligned_page(size + PAGE_SIZE -1);
        page = 0;
        list_for_each(p, &emu->memhdr->block) {
                blk = get_emu10k1_memblk(p, mem.list);
                if (page + psize <= blk->first_page)
                        goto __found_pages;
                page = blk->last_page + 1;
        }
        if (page + psize > emu->max_cache_pages)
                return NULL;

__found_pages:
        /* create a new memory block */
        blk = (struct snd_emu10k1_memblk *)__snd_util_memblk_new(emu->memhdr, psize << PAGE_SHIFT, p->prev);
        if (blk == NULL)
                return NULL;
        blk->mem.offset = aligned_page_offset(page); /* set aligned offset */
        emu10k1_memblk_init(blk);
        return blk;
}


/*
 * check if the given pointer is valid for pages
 */
static int is_valid_page(struct snd_emu10k1 *emu, dma_addr_t addr)
{
        if (addr & ~emu->dma_mask) {
                dev_err_ratelimited(emu->card->dev,
                        "max memory size is 0x%lx (addr = 0x%lx)!!\n",
                        emu->dma_mask, (unsigned long)addr);
                return 0;
        }
        if (addr & (EMUPAGESIZE-1)) {
                dev_err_ratelimited(emu->card->dev, "page is not aligned\n");
                return 0;
        }
        return 1;
}

/*
 * map the given memory block on PTB.
 * if the block is already mapped, update the link order.
 * if no empty pages are found, tries to release unused memory blocks
 * and retry the mapping.
 */
int snd_emu10k1_memblk_map(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
        int err;
        int size;
        struct list_head *p, *nextp;
        struct snd_emu10k1_memblk *deleted;

        guard(spinlock_irqsave)(&emu->memblk_lock);
        if (blk->mapped_page >= 0) {
                /* update order link */
                list_move_tail(&blk->mapped_order_link,
                               &emu->mapped_order_link_head);
                return 0;
        }
        err = map_memblk(emu, blk);
        if (err < 0) {
                /* no enough page - try to unmap some blocks */
                /* starting from the oldest block */
                p = emu->mapped_order_link_head.next;
                for (; p != &emu->mapped_order_link_head; p = nextp) {
                        nextp = p->next;
                        deleted = get_emu10k1_memblk(p, mapped_order_link);
                        if (deleted->map_locked)
                                continue;
                        size = unmap_memblk(emu, deleted);
                        if (size >= blk->pages) {
                                /* ok the empty region is enough large */
                                err = map_memblk(emu, blk);
                                break;
                        }
                }
        }
        return err;
}

EXPORT_SYMBOL(snd_emu10k1_memblk_map);

/*
 * page allocation for DMA
 */
struct snd_util_memblk *
snd_emu10k1_alloc_pages(struct snd_emu10k1 *emu, struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_util_memhdr *hdr;
        struct snd_emu10k1_memblk *blk;
        int page, err, idx;

        if (snd_BUG_ON(!emu))
                return NULL;
        if (snd_BUG_ON(runtime->dma_bytes <= 0 ||
                       runtime->dma_bytes >= (emu->address_mode ? MAXPAGES1 : MAXPAGES0) * EMUPAGESIZE))
                return NULL;
        hdr = emu->memhdr;
        if (snd_BUG_ON(!hdr))
                return NULL;

        guard(mutex)(&hdr->block_mutex);
        blk = search_empty(emu, runtime->dma_bytes);
        if (blk == NULL)
                return NULL;
        /* fill buffer addresses but pointers are not stored so that
         * snd_free_pci_page() is not called in synth_free()
         */
        idx = 0;
        for (page = blk->first_page; page <= blk->last_page; page++, idx++) {
                unsigned long ofs = idx << PAGE_SHIFT;
                dma_addr_t addr;
                if (ofs >= runtime->dma_bytes)
                        addr = emu->silent_page.addr;
                else
                        addr = snd_pcm_sgbuf_get_addr(substream, ofs);
                if (! is_valid_page(emu, addr)) {
                        dev_err_ratelimited(emu->card->dev,
                                "emu: failure page = %d\n", idx);
                        return NULL;
                }
                emu->page_addr_table[page] = addr;
                emu->page_ptr_table[page] = NULL;
        }

        /* set PTB entries */
        blk->map_locked = 1; /* do not unmap this block! */
        err = snd_emu10k1_memblk_map(emu, blk);
        if (err < 0) {
                __snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
                return NULL;
        }
        return (struct snd_util_memblk *)blk;
}


/*
 * release DMA buffer from page table
 */
int snd_emu10k1_free_pages(struct snd_emu10k1 *emu, struct snd_util_memblk *blk)
{
        if (snd_BUG_ON(!emu || !blk))
                return -EINVAL;
        return snd_emu10k1_synth_free(emu, blk);
}

/*
 * allocate DMA pages, widening the allocation if necessary
 *
 * See the comment above snd_emu10k1_detect_iommu() in emu10k1_main.c why
 * this might be needed.
 *
 * If you modify this function check whether __synth_free_pages() also needs
 * changes.
 */
int snd_emu10k1_alloc_pages_maybe_wider(struct snd_emu10k1 *emu, size_t size,
                                        struct snd_dma_buffer *dmab)
{
        if (emu->iommu_workaround) {
                size_t npages = DIV_ROUND_UP(size, PAGE_SIZE);
                size_t size_real = npages * PAGE_SIZE;

                /*
                 * The device has been observed to accesses up to 256 extra
                 * bytes, but use 1k to be safe.
                 */
                if (size_real < size + 1024)
                        size += PAGE_SIZE;
        }

        return snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
                                   &emu->pci->dev, size, dmab);
}

/*
 * memory allocation using multiple pages (for synth)
 * Unlike the DMA allocation above, non-contiguous pages are assined.
 */

/*
 * allocate a synth sample area
 */
struct snd_util_memblk *
snd_emu10k1_synth_alloc(struct snd_emu10k1 *hw, unsigned int size)
{
        struct snd_emu10k1_memblk *blk;
        struct snd_util_memhdr *hdr = hw->memhdr; 

        guard(mutex)(&hdr->block_mutex);
        blk = (struct snd_emu10k1_memblk *)__snd_util_mem_alloc(hdr, size);
        if (blk == NULL)
                return NULL;
        if (synth_alloc_pages(hw, blk)) {
                __snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
                return NULL;
        }
        snd_emu10k1_memblk_map(hw, blk);
        return (struct snd_util_memblk *)blk;
}

EXPORT_SYMBOL(snd_emu10k1_synth_alloc);

/*
 * free a synth sample area
 */
int
snd_emu10k1_synth_free(struct snd_emu10k1 *emu, struct snd_util_memblk *memblk)
{
        struct snd_util_memhdr *hdr = emu->memhdr; 
        struct snd_emu10k1_memblk *blk = (struct snd_emu10k1_memblk *)memblk;

        guard(mutex)(&hdr->block_mutex);
        scoped_guard(spinlock_irqsave, &emu->memblk_lock) {
                if (blk->mapped_page >= 0)
                        unmap_memblk(emu, blk);
        }
        synth_free_pages(emu, blk);
        __snd_util_mem_free(hdr, memblk);
        return 0;
}

EXPORT_SYMBOL(snd_emu10k1_synth_free);

/* check new allocation range */
static void get_single_page_range(struct snd_util_memhdr *hdr,
                                  struct snd_emu10k1_memblk *blk,
                                  int *first_page_ret, int *last_page_ret)
{
        struct list_head *p;
        struct snd_emu10k1_memblk *q;
        int first_page, last_page;
        first_page = blk->first_page;
        p = blk->mem.list.prev;
        if (p != &hdr->block) {
                q = get_emu10k1_memblk(p, mem.list);
                if (q->last_page == first_page)
                        first_page++;  /* first page was already allocated */
        }
        last_page = blk->last_page;
        p = blk->mem.list.next;
        if (p != &hdr->block) {
                q = get_emu10k1_memblk(p, mem.list);
                if (q->first_page == last_page)
                        last_page--; /* last page was already allocated */
        }
        *first_page_ret = first_page;
        *last_page_ret = last_page;
}

/* release allocated pages */
static void __synth_free_pages(struct snd_emu10k1 *emu, int first_page,
                               int last_page)
{
        struct snd_dma_buffer dmab;
        int page;

        dmab.dev.type = SNDRV_DMA_TYPE_DEV;
        dmab.dev.dev = &emu->pci->dev;

        for (page = first_page; page <= last_page; page++) {
                if (emu->page_ptr_table[page] == NULL)
                        continue;
                dmab.area = emu->page_ptr_table[page];
                dmab.addr = emu->page_addr_table[page];

                /*
                 * please keep me in sync with logic in
                 * snd_emu10k1_alloc_pages_maybe_wider()
                 */
                dmab.bytes = PAGE_SIZE;
                if (emu->iommu_workaround)
                        dmab.bytes *= 2;

                snd_dma_free_pages(&dmab);
                emu->page_addr_table[page] = 0;
                emu->page_ptr_table[page] = NULL;
        }
}

/*
 * allocate kernel pages
 */
static int synth_alloc_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
        int page, first_page, last_page;
        struct snd_dma_buffer dmab;

        emu10k1_memblk_init(blk);
        get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
        /* allocate kernel pages */
        for (page = first_page; page <= last_page; page++) {
                if (snd_emu10k1_alloc_pages_maybe_wider(emu, PAGE_SIZE,
                                                        &dmab) < 0)
                        goto __fail;
                if (!is_valid_page(emu, dmab.addr)) {
                        snd_dma_free_pages(&dmab);
                        goto __fail;
                }
                emu->page_addr_table[page] = dmab.addr;
                emu->page_ptr_table[page] = dmab.area;
        }
        return 0;

__fail:
        /* release allocated pages */
        last_page = page - 1;
        __synth_free_pages(emu, first_page, last_page);

        return -ENOMEM;
}

/*
 * free pages
 */
static int synth_free_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
        int first_page, last_page;

        get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
        __synth_free_pages(emu, first_page, last_page);
        return 0;
}

/* calculate buffer pointer from offset address */
static inline void *offset_ptr(struct snd_emu10k1 *emu, int page, int offset)
{
        char *ptr;
        if (snd_BUG_ON(page < 0 || page >= emu->max_cache_pages))
                return NULL;
        ptr = emu->page_ptr_table[page];
        if (! ptr) {
                dev_err(emu->card->dev,
                        "access to NULL ptr: page = %d\n", page);
                return NULL;
        }
        ptr += offset & (PAGE_SIZE - 1);
        return (void*)ptr;
}

/*
 * memset(blk + offset, value, size)
 */
int snd_emu10k1_synth_memset(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
                             int offset, int size, u8 value)
{
        int page, nextofs, end_offset, temp, temp1;
        void *ptr;
        struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;

        if (snd_BUG_ON(offset + size > p->mem.size))
                return -EFAULT;

        offset += blk->offset & (PAGE_SIZE - 1);
        end_offset = offset + size;
        page = get_aligned_page(offset);
        do {
                nextofs = aligned_page_offset(page + 1);
                temp = nextofs - offset;
                temp1 = end_offset - offset;
                if (temp1 < temp)
                        temp = temp1;
                ptr = offset_ptr(emu, page + p->first_page, offset);
                if (ptr)
                        memset(ptr, value, temp);
                offset = nextofs;
                page++;
        } while (offset < end_offset);
        return 0;
}

EXPORT_SYMBOL(snd_emu10k1_synth_memset);

// Note that the value is assumed to be suitably repetitive.
static void xor_range(void *ptr, int size, u32 value)
{
        if ((long)ptr & 1) {
                *(u8 *)ptr ^= (u8)value;
                ptr++;
                size--;
        }
        if (size > 1 && ((long)ptr & 2)) {
                *(u16 *)ptr ^= (u16)value;
                ptr += 2;
                size -= 2;
        }
        while (size > 3) {
                *(u32 *)ptr ^= value;
                ptr += 4;
                size -= 4;
        }
        if (size > 1) {
                *(u16 *)ptr ^= (u16)value;
                ptr += 2;
                size -= 2;
        }
        if (size > 0)
                *(u8 *)ptr ^= (u8)value;
}

/*
 * copy_from_user(blk + offset, data, size) ^ xor
 */
int snd_emu10k1_synth_copy_from_user(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
                                     int offset, const char __user *data, int size, u32 xor)
{
        int page, nextofs, end_offset, temp, temp1;
        void *ptr;
        struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;

        if (snd_BUG_ON(offset + size > p->mem.size))
                return -EFAULT;

        offset += blk->offset & (PAGE_SIZE - 1);
        end_offset = offset + size;
        page = get_aligned_page(offset);
        do {
                nextofs = aligned_page_offset(page + 1);
                temp = nextofs - offset;
                temp1 = end_offset - offset;
                if (temp1 < temp)
                        temp = temp1;
                ptr = offset_ptr(emu, page + p->first_page, offset);
                if (ptr) {
                        if (copy_from_user(ptr, data, temp))
                                return -EFAULT;
                        if (xor)
                                xor_range(ptr, temp, xor);
                }
                offset = nextofs;
                data += temp;
                page++;
        } while (offset < end_offset);
        return 0;
}

EXPORT_SYMBOL(snd_emu10k1_synth_copy_from_user);