diff options
Diffstat (limited to 'libiot/spiffs/spiffs_cache.c')
| -rw-r--r-- | libiot/spiffs/spiffs_cache.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/libiot/spiffs/spiffs_cache.c b/libiot/spiffs/spiffs_cache.c new file mode 100644 index 0000000..018f763 --- /dev/null +++ b/libiot/spiffs/spiffs_cache.c @@ -0,0 +1,314 @@ +/* + * spiffs_cache.c + * + * Created on: Jun 23, 2013 + * Author: petera + */ + +#include "spiffs.h" +#include "spiffs_nucleus.h" + +#if SPIFFS_CACHE + +// returns cached page for give page index, or null if no such cached page +static spiffs_cache_page *spiffs_cache_page_get(spiffs *fs, spiffs_page_ix pix) { + spiffs_cache *cache = spiffs_get_cache(fs); + if ((cache->cpage_use_map & cache->cpage_use_mask) == 0) return 0; + int i; + for (i = 0; i < cache->cpage_count; i++) { + spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i); + if ((cache->cpage_use_map & (1<<i)) && + (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) == 0 && + cp->pix == pix ) { + SPIFFS_CACHE_DBG("CACHE_GET: have cache page "_SPIPRIi" for "_SPIPRIpg"\n", i, pix); + cp->last_access = cache->last_access; + return cp; + } + } + //SPIFFS_CACHE_DBG("CACHE_GET: no cache for "_SPIPRIpg"\n", pix); + return 0; +} + +// frees cached page +static s32_t spiffs_cache_page_free(spiffs *fs, int ix, u8_t write_back) { + s32_t res = SPIFFS_OK; + spiffs_cache *cache = spiffs_get_cache(fs); + spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, ix); + if (cache->cpage_use_map & (1<<ix)) { + if (write_back && + (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) == 0 && + (cp->flags & SPIFFS_CACHE_FLAG_DIRTY)) { + u8_t *mem = spiffs_get_cache_page(fs, cache, ix); + res = SPIFFS_HAL_WRITE(fs, SPIFFS_PAGE_TO_PADDR(fs, cp->pix), SPIFFS_CFG_LOG_PAGE_SZ(fs), mem); + } + + cp->flags = 0; + cache->cpage_use_map &= ~(1 << ix); + + if (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) { + SPIFFS_CACHE_DBG("CACHE_FREE: free cache page "_SPIPRIi" objid "_SPIPRIid"\n", ix, cp->obj_id); + } else { + SPIFFS_CACHE_DBG("CACHE_FREE: free cache page "_SPIPRIi" pix "_SPIPRIpg"\n", ix, cp->pix); + } + } + + return res; +} + +// removes the oldest accessed cached page +static s32_t spiffs_cache_page_remove_oldest(spiffs *fs, u8_t flag_mask, u8_t flags) { + s32_t res = SPIFFS_OK; + spiffs_cache *cache = spiffs_get_cache(fs); + + if ((cache->cpage_use_map & cache->cpage_use_mask) != cache->cpage_use_mask) { + // at least one free cpage + return SPIFFS_OK; + } + + // all busy, scan thru all to find the cpage which has oldest access + int i; + int cand_ix = -1; + u32_t oldest_val = 0; + for (i = 0; i < cache->cpage_count; i++) { + spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i); + if ((cache->last_access - cp->last_access) > oldest_val && + (cp->flags & flag_mask) == flags) { + oldest_val = cache->last_access - cp->last_access; + cand_ix = i; + } + } + + if (cand_ix >= 0) { + res = spiffs_cache_page_free(fs, cand_ix, 1); + } + + return res; +} + +// allocates a new cached page and returns it, or null if all cache pages are busy +static spiffs_cache_page *spiffs_cache_page_allocate(spiffs *fs) { + spiffs_cache *cache = spiffs_get_cache(fs); + if (cache->cpage_use_map == 0xffffffff) { + // out of cache memory + return 0; + } + int i; + for (i = 0; i < cache->cpage_count; i++) { + if ((cache->cpage_use_map & (1<<i)) == 0) { + spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i); + cache->cpage_use_map |= (1<<i); + cp->last_access = cache->last_access; + SPIFFS_CACHE_DBG("CACHE_ALLO: allocated cache page "_SPIPRIi"\n", i); + return cp; + } + } + // out of cache entries + return 0; +} + +// drops the cache page for give page index +void spiffs_cache_drop_page(spiffs *fs, spiffs_page_ix pix) { + spiffs_cache_page *cp = spiffs_cache_page_get(fs, pix); + if (cp) { + spiffs_cache_page_free(fs, cp->ix, 0); + } +} + +// ------------------------------ + +// reads from spi flash or the cache +s32_t spiffs_phys_rd( + spiffs *fs, + u8_t op, + spiffs_file fh, + u32_t addr, + u32_t len, + u8_t *dst) { + (void)fh; + s32_t res = SPIFFS_OK; + spiffs_cache *cache = spiffs_get_cache(fs); + spiffs_cache_page *cp = spiffs_cache_page_get(fs, SPIFFS_PADDR_TO_PAGE(fs, addr)); + cache->last_access++; + if (cp) { + // we've already got one, you see +#if SPIFFS_CACHE_STATS + fs->cache_hits++; +#endif + cp->last_access = cache->last_access; + u8_t *mem = spiffs_get_cache_page(fs, cache, cp->ix); + memcpy(dst, &mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], len); + } else { + if ((op & SPIFFS_OP_TYPE_MASK) == SPIFFS_OP_T_OBJ_LU2) { + // for second layer lookup functions, we do not cache in order to prevent shredding + return SPIFFS_HAL_READ(fs, addr, len, dst); + } +#if SPIFFS_CACHE_STATS + fs->cache_misses++; +#endif + // this operation will always free one cache page (unless all already free), + // the result code stems from the write operation of the possibly freed cache page + res = spiffs_cache_page_remove_oldest(fs, SPIFFS_CACHE_FLAG_TYPE_WR, 0); + + cp = spiffs_cache_page_allocate(fs); + if (cp) { + cp->flags = SPIFFS_CACHE_FLAG_WRTHRU; + cp->pix = SPIFFS_PADDR_TO_PAGE(fs, addr); + + s32_t res2 = SPIFFS_HAL_READ(fs, + addr - SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr), + SPIFFS_CFG_LOG_PAGE_SZ(fs), + spiffs_get_cache_page(fs, cache, cp->ix)); + if (res2 != SPIFFS_OK) { + // honor read failure before possible write failure (bad idea?) + res = res2; + } + u8_t *mem = spiffs_get_cache_page(fs, cache, cp->ix); + memcpy(dst, &mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], len); + } else { + // this will never happen, last resort for sake of symmetry + s32_t res2 = SPIFFS_HAL_READ(fs, addr, len, dst); + if (res2 != SPIFFS_OK) { + // honor read failure before possible write failure (bad idea?) + res = res2; + } + } + } + return res; +} + +// writes to spi flash and/or the cache +s32_t spiffs_phys_wr( + spiffs *fs, + u8_t op, + spiffs_file fh, + u32_t addr, + u32_t len, + u8_t *src) { + (void)fh; + spiffs_page_ix pix = SPIFFS_PADDR_TO_PAGE(fs, addr); + spiffs_cache *cache = spiffs_get_cache(fs); + spiffs_cache_page *cp = spiffs_cache_page_get(fs, pix); + + if (cp && (op & SPIFFS_OP_COM_MASK) != SPIFFS_OP_C_WRTHRU) { + // have a cache page + // copy in data to cache page + + if ((op & SPIFFS_OP_COM_MASK) == SPIFFS_OP_C_DELE && + (op & SPIFFS_OP_TYPE_MASK) != SPIFFS_OP_T_OBJ_LU) { + // page is being deleted, wipe from cache - unless it is a lookup page + spiffs_cache_page_free(fs, cp->ix, 0); + return SPIFFS_HAL_WRITE(fs, addr, len, src); + } + + u8_t *mem = spiffs_get_cache_page(fs, cache, cp->ix); + memcpy(&mem[SPIFFS_PADDR_TO_PAGE_OFFSET(fs, addr)], src, len); + + cache->last_access++; + cp->last_access = cache->last_access; + + if (cp->flags & SPIFFS_CACHE_FLAG_WRTHRU) { + // page is being updated, no write-cache, just pass thru + return SPIFFS_HAL_WRITE(fs, addr, len, src); + } else { + return SPIFFS_OK; + } + } else { + // no cache page, no write cache - just write thru + return SPIFFS_HAL_WRITE(fs, addr, len, src); + } +} + +#if SPIFFS_CACHE_WR +// returns the cache page that this fd refers, or null if no cache page +spiffs_cache_page *spiffs_cache_page_get_by_fd(spiffs *fs, spiffs_fd *fd) { + spiffs_cache *cache = spiffs_get_cache(fs); + + if ((cache->cpage_use_map & cache->cpage_use_mask) == 0) { + // all cpages free, no cpage cannot be assigned to obj_id + return 0; + } + + int i; + for (i = 0; i < cache->cpage_count; i++) { + spiffs_cache_page *cp = spiffs_get_cache_page_hdr(fs, cache, i); + if ((cache->cpage_use_map & (1<<i)) && + (cp->flags & SPIFFS_CACHE_FLAG_TYPE_WR) && + cp->obj_id == fd->obj_id) { + return cp; + } + } + + return 0; +} + +// allocates a new cache page and refers this to given fd - flushes an old cache +// page if all cache is busy +spiffs_cache_page *spiffs_cache_page_allocate_by_fd(spiffs *fs, spiffs_fd *fd) { + // before this function is called, it is ensured that there is no already existing + // cache page with same object id + spiffs_cache_page_remove_oldest(fs, SPIFFS_CACHE_FLAG_TYPE_WR, 0); + spiffs_cache_page *cp = spiffs_cache_page_allocate(fs); + if (cp == 0) { + // could not get cache page + return 0; + } + + cp->flags = SPIFFS_CACHE_FLAG_TYPE_WR; + cp->obj_id = fd->obj_id; + fd->cache_page = cp; + return cp; +} + +// unrefers all fds that this cache page refers to and releases the cache page +void spiffs_cache_fd_release(spiffs *fs, spiffs_cache_page *cp) { + if (cp == 0) return; + u32_t i; + spiffs_fd *fds = (spiffs_fd *)fs->fd_space; + for (i = 0; i < fs->fd_count; i++) { + spiffs_fd *cur_fd = &fds[i]; + if (cur_fd->file_nbr != 0 && cur_fd->cache_page == cp) { + cur_fd->cache_page = 0; + } + } + spiffs_cache_page_free(fs, cp->ix, 0); + + cp->obj_id = 0; +} + +#endif + +// initializes the cache +void spiffs_cache_init(spiffs *fs) { + if (fs->cache == 0) return; + u32_t sz = fs->cache_size; + u32_t cache_mask = 0; + int i; + int cache_entries = + (sz - sizeof(spiffs_cache)) / (SPIFFS_CACHE_PAGE_SIZE(fs)); + if (cache_entries <= 0) return; + + for (i = 0; i < cache_entries; i++) { + cache_mask <<= 1; + cache_mask |= 1; + } + + spiffs_cache cache; + memset(&cache, 0, sizeof(spiffs_cache)); + cache.cpage_count = cache_entries; + cache.cpages = (u8_t *)((u8_t *)fs->cache + sizeof(spiffs_cache)); + + cache.cpage_use_map = 0xffffffff; + cache.cpage_use_mask = cache_mask; + memcpy(fs->cache, &cache, sizeof(spiffs_cache)); + + spiffs_cache *c = spiffs_get_cache(fs); + + memset(c->cpages, 0, c->cpage_count * SPIFFS_CACHE_PAGE_SIZE(fs)); + + c->cpage_use_map &= ~(c->cpage_use_mask); + for (i = 0; i < cache.cpage_count; i++) { + spiffs_get_cache_page_hdr(fs, c, i)->ix = i; + } +} + +#endif // SPIFFS_CACHE |