ra8_fs_fat_bytes_internal.h

Go to the documentation of this file.

 
#pragma once
 
#include <stdint.h>
 
#include "ra8_attributes.h"
#include "ra8_fs_fat_types_internal.h"
 
/* =============================================================================
 * The sector arena -- four fixed-role bounce buffers (#683)
 * =============================================================================
 *
 * Sector buffers grew from 512 bytes to ::k_ra8_fs_sector_max (4 KiB) when the
 * sector size became a runtime property, and a 4 KiB frame does not belong on
 * a firmware stack budgeted in the low kilobytes. The library is serialised by
 * contract (one lock, no recursion, no reentrancy), so every bounce buffer
 * lives in a small static arena instead, addressed by ROLE. The roles encode
 * the only nesting the call graph performs, so two live buffers can never
 * alias:
 *
 *   - WALK -- a directory/metadata sector held across a scan or a
 *     read-modify-write of a directory entry. Walk holders may call FAT-entry
 *     helpers (which use FAT/FAT2) and leaf I/O helpers (which use IO), and
 *     never each other while their sector is live.
 *   - FAT  -- the sector holding a FAT entry (`priv_fat_get` / the setters).
 *   - FAT2 -- the following sector, live only while a FAT12 entry straddles.
 *   - IO   -- leaf data/bitmap sector I/O: loaded, consumed/patched, written,
 *     dead before any other buffer user runs.
 *
 * A function taking a buffer must finish with it before calling anything that
 * takes the same role -- the discipline every converted call site follows and
 * the reviews on this module enforce.
 */

RA8_PRIV
uint8_t* priv_sec_walk(void);

RA8_PRIV
uint8_t* priv_sec_fat(void);

RA8_PRIV
uint8_t* priv_sec_fat2(void);

RA8_PRIV
uint8_t* priv_sec_io(void);

RA8_PRIV
void priv_byte_fill(uint8_t* dst, uint8_t value, uint32_t n);

extern const uint8_t k_zero_sector[k_ra8_fs_sector_max];

RA8_PRIV
uint16_t priv_rd16(const uint8_t* p);

RA8_PRIV
uint32_t priv_rd32(const uint8_t* p);

RA8_PRIV
uint64_t priv_rd64(const uint8_t* p);

RA8_PRIV
uint32_t priv_bps(const ra8_fs_mount_t* m);

RA8_PRIV
uint32_t priv_cluster_bytes(const ra8_fs_mount_t* m);

RA8_PRIV
uint32_t priv_dir_eps(const ra8_fs_mount_t* m);

RA8_PRIV
void priv_wr16(uint8_t* p, uint16_t v);

RA8_PRIV
void priv_wr32(uint8_t* p, uint32_t v);

RA8_PRIV
void priv_wr64(uint8_t* p, uint64_t v);