Blank-card FAT16/FAT32 sparse-sector formatters (–sd-new). More...

#include <string.h>
#include "board_periph_sd_internal.h"
#include "emu_host_io_internal.h"

Include dependency graph for board_periph_sd_format.c:

Enumerations
enum	sd_le_const_t : uint8_t { k_le_byte0 = 0U , k_le_byte1 = 1U , k_le_byte2 = 2U , k_le_byte3 = 3U , k_le_shift_b1 = 8U , k_le_shift_b2 = 16U , k_le_shift_b3 = 24U , k_le_byte_mask = 0xFFU }
	Little-endian byte offsets, shifts, and mask for image serialization. More...
enum	sd_bpb_off_t : uint16_t { k_bpb_jmp0 = 0U , k_bpb_jmp1 = 1U , k_bpb_jmp2 = 2U , k_bpb_oem = 3U , k_bpb_bytes_per_sec = 11U , k_bpb_sec_per_clus = 13U , k_bpb_resv_sec = 14U , k_bpb_num_fats = 16U , k_bpb_root_ents = 17U , k_bpb_totsec16 = 19U , k_bpb_media = 21U , k_bpb_fatsz16 = 22U , k_bpb_sec_per_trk = 24U , k_bpb_num_heads = 26U , k_bpb_totsec32 = 32U , k_bpb_fatsz32 = 36U , k_bpb16_drive_num = 36U , k_bpb16_boot_sig = 38U , k_bpb16_volid = 39U , k_bpb16_vol_label = 43U , k_bpb32_root_clus = 44U , k_bpb32_fsinfo_sec = 48U , k_bpb32_bkboot_sec = 50U , k_bpb16_fstype = 54U , k_bpb32_drive_num = 64U , k_bpb32_boot_sig = 66U , k_bpb32_volid = 67U , k_bpb32_vol_label = 71U , k_bpb32_fstype = 82U , k_bpb_sig_lo = 510U , k_bpb_sig_hi = 511U }
	FAT BPB byte offsets within a sector (FAT16 + FAT32 layouts). More...
enum	sd_bpb_val_t : uint32_t { k_bpb_jmp_b0 = 0xEBU , k_bpb_jmp_b1 = 0x58U , k_bpb_jmp_b2 = 0x90U , k_bpb_oem_len = 8U , k_bpb_fstype_len = 8U , k_bpb_sig_byte_lo = 0x55U , k_bpb_sig_byte_hi = 0xAAU , k_bpb_num_fats_val = 2U , k_bpb_media_fixed = 0xF8U , k_bpb_sec_per_trk_val = 63U , k_bpb_num_heads_val = 255U , k_bpb_drive_num_val = 0x80U , k_bpb_ext_boot_sig = 0x29U , k_bpb_dir_ent_size = 32U , k_bpb_fat16_div = 256U , k_bpb_fat32_div = 128U , k_fat16_eoc_clus0 = 0xFFF8U , k_fat16_eoc_clus1 = 0xFFFFU , k_fat32_eoc_media = 0x0FFFFFF8U , k_fat32_eoc = 0x0FFFFFFFU , k_fat32_root_clus = 2U , k_fat32_fsinfo_sec = 1U , k_fat32_bkboot_sec = 6U , k_fsi_lead_sig = 0x41615252U , k_fsi_struc_sig = 0x61417272U , k_fsi_trail_sig = 0xAA550000U , k_fsi_off_lead = 0U , k_fsi_off_struc = 484U , k_fsi_off_free = 488U , k_fsi_off_nxtfree = 492U , k_fsi_off_trail = 508U , k_fsi_free_unknown = 0xFFFFFFFFU , k_fsi_nxt_free = 3U , k_fat_ent1_off = 2U , k_fat32_ent1_off = 4U , k_fat32_ent2_off = 8U }
	FAT BPB literal field values + the FSInfo signatures. More...

Functions
static RA8_INTERNAL void	internal_sd_put16 (uint8_t *p, uint16_t v)
	Store one 16-bit image field in little-endian order.
static RA8_INTERNAL void	internal_sd_put32 (uint8_t *p, uint32_t v)
	Store one 32-bit image field in little-endian order.
static RA8_INTERNAL void	internal_sd_boot_frame (uint8_t img, const char oem)
	Write the shared boot prologue and trailing boot signature.
void	priv_board_sd_label_field (uint8_t dst, const char label)
	Pad an ASCII volume label to the 11-byte 8.3 field (space-filled).
static RA8_INTERNAL uint32_t	internal_fat16_solve_geometry (uint32_t total_sectors, uint32_t root_sectors, uint32_t *fatsz)
	Solve the FAT16 cluster size and FAT length for `total_sectors`.
static RA8_INTERNAL void	internal_fat16_write_bpb (uint8_t img, uint32_t total_sectors, uint32_t spc, uint32_t fatsz, const char label)
	Write the FAT16 BIOS Parameter Block into sector 0 of `img`.
static RA8_INTERNAL bool	internal_write_sector (int image_fd, uint32_t sector, const uint8_t *data)
	Write one complete sector at its checked positioned offset.
bool	priv_board_sd_format_fat16 (int image_fd, uint32_t total_sectors, const char label, uint32_t out_spc)
	Format the attached sparse backend as a FAT16 volume.
static RA8_INTERNAL uint32_t	internal_sd_fat32_geometry (uint32_t total_sectors, uint32_t out_fatsz, uint32_t out_clusters)
	Compute FAT32 volume geometry for a card of total_sectors.
static RA8_INTERNAL void	internal_fat32_write_bpb (uint8_t img, uint32_t total_sectors, uint32_t spc, uint32_t fatsz, const char label)
	Serialize one deterministic FAT32 BIOS Parameter Block.
bool	priv_board_sd_format_fat32 (int image_fd, uint32_t total_sectors, const char label, uint32_t out_spc)
	Format the attached sparse backend as a FAT32 volume.

Detailed Description

Blank-card FAT16/FAT32 sparse-sector formatters (–sd-new).

The bounded sector formatters board_sd_attach_blank uses to build an empty FAT volume in an anonymous sparse file. No peripheral block is registered here (registration is constructor-based and stays with the card model), so this helper TU rides the board_periph_*.c build glob with no CMake edit.

Copyright: Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since: 0.1.0

Definition in file board_periph_sd_format.c.

Enumeration Type Documentation

◆ sd_bpb_off_t

enum sd_bpb_off_t : uint16_t

FAT BPB byte offsets within a sector (FAT16 + FAT32 layouts).

Enumerator
k_bpb_jmp0	Jump instruction byte 0.
k_bpb_jmp1	Jump instruction byte 1.
k_bpb_jmp2	Jump instruction byte 2.
k_bpb_oem	OEM name (8 bytes).
k_bpb_bytes_per_sec	BPB_BytsPerSec.
k_bpb_sec_per_clus	BPB_SecPerClus.
k_bpb_resv_sec	BPB_RsvdSecCnt.
k_bpb_num_fats	BPB_NumFATs.
k_bpb_root_ents	BPB_RootEntCnt.
k_bpb_totsec16	BPB_TotSec16.
k_bpb_media	BPB_Media.
k_bpb_fatsz16	BPB_FATSz16.
k_bpb_sec_per_trk	BPB_SecPerTrk.
k_bpb_num_heads	BPB_NumHeads.
k_bpb_totsec32	BPB_TotSec32.
k_bpb_fatsz32	BPB_FATSz32 (FAT32 only).
k_bpb16_drive_num	BS_DrvNum (FAT16).
k_bpb16_boot_sig	BS_BootSig (FAT16).
k_bpb16_volid	BS_VolID (FAT16).
k_bpb16_vol_label	BS_VolLab (FAT16, 11 bytes).
k_bpb32_root_clus	BPB_RootClus (FAT32).
k_bpb32_fsinfo_sec	BPB_FSInfo (FAT32).
k_bpb32_bkboot_sec	BPB_BkBootSec (FAT32).
k_bpb16_fstype	BS_FilSysType (FAT16, 8 bytes).
k_bpb32_drive_num	BS_DrvNum (FAT32).
k_bpb32_boot_sig	BS_BootSig (FAT32).
k_bpb32_volid	BS_VolID (FAT32).
k_bpb32_vol_label	BS_VolLab (FAT32, 11 bytes).
k_bpb32_fstype	BS_FilSysType (FAT32, 8 bytes).
k_bpb_sig_lo	0x55 boot-signature byte.
k_bpb_sig_hi	0xAA boot-signature byte.

Definition at line 79 of file board_periph_sd_format.c.

◆ sd_bpb_val_t

enum sd_bpb_val_t : uint32_t

FAT BPB literal field values + the FSInfo signatures.

Enumerator
k_bpb_jmp_b0	Boot jump byte 0 (JMP short).
k_bpb_jmp_b1	Boot jump byte 1 (offset).
k_bpb_jmp_b2	Boot jump byte 2 (NOP).
k_bpb_oem_len	OEM-name field length.
k_bpb_fstype_len	FilSysType field length.
k_bpb_sig_byte_lo	Boot signature low byte.
k_bpb_sig_byte_hi	Boot signature high byte.
k_bpb_num_fats_val	Number of FAT copies.
k_bpb_media_fixed	Media descriptor: fixed disk.
k_bpb_sec_per_trk_val	Sectors per track.
k_bpb_num_heads_val	Number of heads.
k_bpb_drive_num_val	Drive number (hard disk).
k_bpb_ext_boot_sig	Extended boot signature present.
k_bpb_dir_ent_size	Bytes per directory entry.
k_bpb_fat16_div	512-byte sector / 2-byte FAT16 ent.
k_bpb_fat32_div	FAT32 FAT-size divisor multiplier.
k_fat16_eoc_clus0	FAT16 entry 0: media + EOC bits.
k_fat16_eoc_clus1	FAT16 entry 1: end-of-chain.
k_fat32_eoc_media	FAT32 entry 0: media + EOC.
k_fat32_eoc	FAT32 end-of-chain marker.
k_fat32_root_clus	FAT32 root directory cluster.
k_fat32_fsinfo_sec	FSInfo sector index.
k_fat32_bkboot_sec	Backup boot-sector index.
k_fsi_lead_sig	FSInfo lead signature "RRaA".
k_fsi_struc_sig	FSInfo struct signature "rrAa".
k_fsi_trail_sig	FSInfo trailing signature.
k_fsi_off_lead	FSInfo lead-sig offset.
k_fsi_off_struc	FSInfo struct-sig offset.
k_fsi_off_free	FSInfo free-cluster-count off.
k_fsi_off_nxtfree	FSInfo next-free-cluster off.
k_fsi_off_trail	FSInfo trailing-sig offset.
k_fsi_free_unknown	Free-cluster count unknown.
k_fsi_nxt_free	Next-free cluster hint.
k_fat_ent1_off	FAT16 entry-1 byte offset.
k_fat32_ent1_off	FAT32 entry-1 byte offset.
k_fat32_ent2_off	FAT32 entry-2 byte offset.

Definition at line 114 of file board_periph_sd_format.c.

◆ sd_le_const_t

enum sd_le_const_t : uint8_t

Little-endian byte offsets, shifts, and mask for image serialization.

Enumerator
k_le_byte0	Least-significant byte offset.
k_le_byte1	Second byte offset.
k_le_byte2	Third byte offset.
k_le_byte3	Most-significant byte offset.
k_le_shift_b1	Shift to extract byte 1.
k_le_shift_b2	Shift to extract byte 2.
k_le_shift_b3	Shift to extract byte 3.
k_le_byte_mask	Low-byte mask.

Definition at line 29 of file board_periph_sd_format.c.

Function Documentation

◆ internal_fat16_solve_geometry()

RA8_INTERNAL uint32_t internal_fat16_solve_geometry	(	uint32_t	total_sectors,
		uint32_t	root_sectors,
		uint32_t *	fatsz )

static

Solve the FAT16 cluster size and FAT length for total_sectors.

Doubles sectors-per-cluster until the cluster count fits under the FAT16 ceiling, recomputing the FAT length each round because the two depend on each other. Stops at k_fmt_spc_max, the largest cluster the format allows.

Parameters

[in]	total_sectors	Card size in 512-byte sectors.
[in]	root_sectors	Sectors the fixed root directory occupies.
[out]	fatsz	Receives the per-copy FAT length in sectors.

Returns: Sectors per cluster.

Return values

spc	Power-of-two sectors per cluster, at most k_fmt_spc_max.

Precondition: fatsz is non-NULL.; total_sectors leaves room for the reserved and root regions.

Postcondition: The returned cluster size is a power of two, at most k_fmt_spc_max.; *fatsz covers every cluster the returned size yields.

Note: Thread-safe: pure arithmetic over its arguments.

Since: 0.1.0

Definition at line 213 of file board_periph_sd_format.c.

References k_bpb_fat16_div, k_bpb_num_fats_val, k_fmt_fat16_max, k_fmt_resv_f16, and k_fmt_spc_max.

Referenced by priv_board_sd_format_fat16().

◆ internal_fat16_write_bpb()

RA8_INTERNAL void internal_fat16_write_bpb	(	uint8_t *	img,
		uint32_t	total_sectors,
		uint32_t	spc,
		uint32_t	fatsz,
		const char *	label )

static

Write the FAT16 BIOS Parameter Block into sector 0 of img.

Serializes deterministic geometry, identifiers, label, and FAT16 type fields into the already zeroed sector without touching another sector.

Parameters

[out]	img	Card image.
[in]	total_sectors	Card size in sectors.
[in]	spc	Sectors per cluster.
[in]	fatsz	Per-copy FAT length in sectors.
[in]	label	Volume label for the boot-sector field.

Precondition: img covers at least one sector.; spc and fatsz came from fat16_solve_geometry().

Postcondition: The sector count lands in the 16- or 32-bit field as its size requires.; The label and "FAT16 " type string are space-padded to width.

Note: Not thread-safe with respect to img.

Since: 0.1.0

Definition at line 254 of file board_periph_sd_format.c.

References internal_sd_boot_frame(), internal_sd_put16(), internal_sd_put32(), k_bpb16_boot_sig, k_bpb16_drive_num, k_bpb16_fstype, k_bpb16_vol_label, k_bpb16_volid, k_bpb_bytes_per_sec, k_bpb_drive_num_val, k_bpb_ext_boot_sig, k_bpb_fatsz16, k_bpb_fstype_len, k_bpb_media, k_bpb_media_fixed, k_bpb_num_fats, k_bpb_num_fats_val, k_bpb_num_heads, k_bpb_num_heads_val, k_bpb_resv_sec, k_bpb_root_ents, k_bpb_sec_per_clus, k_bpb_sec_per_trk, k_bpb_sec_per_trk_val, k_bpb_totsec16, k_bpb_totsec32, k_fmt_resv_f16, k_fmt_root_ents, k_fmt_sec_bytes, k_fmt_totsec16_max, k_fmt_volid, memcpy(), priv_board_sd_label_field(), and RA8_INTERNAL.

Referenced by priv_board_sd_format_fat16().

◆ internal_fat32_write_bpb()

RA8_INTERNAL void internal_fat32_write_bpb	(	uint8_t *	img,
		uint32_t	total_sectors,
		uint32_t	spc,
		uint32_t	fatsz,
		const char *	label )

static

Serialize one deterministic FAT32 BIOS Parameter Block.

Writes common geometry, FAT32 root/FSInfo locations, volume identity, space-padded label, and type string into an already zeroed boot sector.

Parameters

[out]	img	Zeroed boot-sector buffer.
[in]	total_sectors	Exact card sector count.
[in]	spc	Solved sectors per cluster.
[in]	fatsz	Solved sectors per FAT copy.
[in]	label	Optional NUL-terminated volume label.

Precondition: img spans one writable k_fmt_sec_bytes sector.; spc and fatsz came from internal_sd_fat32_geometry.

Postcondition: FAT32 BPB, extended fields, signature, and label are initialized.; Bytes outside named fields remain zero.

Note: Pure apart from caller-owned sector; thread-safe for distinct buffers.

Since: 0.1.0

Definition at line 406 of file board_periph_sd_format.c.

References internal_sd_boot_frame(), internal_sd_put16(), internal_sd_put32(), k_bpb32_bkboot_sec, k_bpb32_boot_sig, k_bpb32_drive_num, k_bpb32_fsinfo_sec, k_bpb32_fstype, k_bpb32_root_clus, k_bpb32_vol_label, k_bpb32_volid, k_bpb_bytes_per_sec, k_bpb_drive_num_val, k_bpb_ext_boot_sig, k_bpb_fatsz16, k_bpb_fatsz32, k_bpb_fstype_len, k_bpb_media, k_bpb_media_fixed, k_bpb_num_fats, k_bpb_num_fats_val, k_bpb_num_heads, k_bpb_num_heads_val, k_bpb_resv_sec, k_bpb_root_ents, k_bpb_sec_per_clus, k_bpb_sec_per_trk, k_bpb_sec_per_trk_val, k_bpb_totsec16, k_bpb_totsec32, k_fat32_bkboot_sec, k_fat32_fsinfo_sec, k_fat32_root_clus, k_fmt_resv_f32, k_fmt_sec_bytes, k_fmt_volid, memcpy(), priv_board_sd_label_field(), and RA8_INTERNAL.

Referenced by priv_board_sd_format_fat32().

◆ internal_sd_boot_frame()

RA8_INTERNAL void internal_sd_boot_frame	(	uint8_t *	img,
		const char *	oem )

static

Write the shared boot prologue and trailing boot signature.

Installs the deterministic jump, exact eight-byte OEM field, and 0x55AA marker.

Parameters

[out]	img	Zeroed boot-sector buffer.
[in]	oem	Exact eight-byte OEM spelling.

Precondition: img spans one writable k_fmt_sec_bytes sector.; oem spans at least k_bpb_oem_len readable bytes.

Postcondition: Named prologue and signature bytes are initialized.; All bytes outside those fixed fields remain unchanged.

Note: Pure apart from caller-owned sector and thread-safe.

Since: 0.1.0

Definition at line 165 of file board_periph_sd_format.c.

References k_bpb_jmp0, k_bpb_jmp1, k_bpb_jmp2, k_bpb_jmp_b0, k_bpb_jmp_b1, k_bpb_jmp_b2, k_bpb_oem, k_bpb_oem_len, k_bpb_sig_byte_hi, k_bpb_sig_byte_lo, k_bpb_sig_hi, k_bpb_sig_lo, memcpy(), and RA8_INTERNAL.

Referenced by internal_fat16_write_bpb(), and internal_fat32_write_bpb().

◆ internal_sd_fat32_geometry()

RA8_INTERNAL uint32_t internal_sd_fat32_geometry	(	uint32_t	total_sectors,
		uint32_t *	out_fatsz,
		uint32_t *	out_clusters )

static

Compute FAT32 volume geometry for a card of total_sectors.

Iteratively grows the sectors-per-cluster (spc) so the FAT stays bounded and the cluster size is realistic (8 KiB at ~2 GiB, 32 KiB at ~8 GiB+), capped at the FAT32 cluster ceiling k_fmt_spc_max; k_fmt_fat32_pref keeps small cards at 1 spc. For each candidate spc it derives the FAT size (in sectors) using the Microsoft FAT32 divisor ((256 * spc) + NumFATs) / 2 = 128 * spc + 1 and the resulting cluster count. Extracted verbatim from sd_format_fat32().

Parameters

[in]	total_sectors	Card size in 512-byte sectors.
[out]	out_fatsz	Receives the chosen FAT size in sectors.
[out]	out_clusters	Receives the resulting data-cluster count.

Returns: The chosen sectors-per-cluster value.

Return values

spc	Sectors-per-cluster (power of two, 1 .. k_fmt_spc_max).

Precondition: out_fatsz and out_clusters are non-null.; total_sectors exceeds the FAT32 reserved-sector count.

Postcondition: *out_fatsz and *out_clusters hold the geometry for the return value.; The returned spc is a power of two not exceeding k_fmt_spc_max.

Note: Pure computation; touches no image buffer. Not thread-safe by contract (operates only on caller-provided locals).

Since: 0.1.0

Definition at line 360 of file board_periph_sd_format.c.

References k_bpb_fat32_div, k_fmt_fat32_pref, k_fmt_resv_f32, and k_fmt_spc_max.

Referenced by priv_board_sd_format_fat32().

◆ internal_sd_put16()

RA8_INTERNAL void internal_sd_put16	(	uint8_t *	p,
		uint16_t	v )

static

Store one 16-bit image field in little-endian order.

Writes both bytes explicitly so serialization is host-independent.

Parameters

[out]	p	Destination spanning two bytes.
[in]	v	Value to encode.

Precondition: p is non-null and writable for two bytes.; v may be any uint16_t value.

Postcondition: Exactly two bytes contain v least-significant byte first.; No byte beyond the two-byte field is changed.

Note: Pure apart from caller output and thread-safe.

Since: 0.1.0

Definition at line 52 of file board_periph_sd_format.c.

References k_le_byte0, k_le_byte1, k_le_byte_mask, k_le_shift_b1, and RA8_INTERNAL.

Referenced by internal_fat16_write_bpb(), internal_fat32_write_bpb(), and priv_board_sd_format_fat16().

◆ internal_sd_put32()

RA8_INTERNAL void internal_sd_put32	(	uint8_t *	p,
		uint32_t	v )

static

Store one 32-bit image field in little-endian order.

Writes all four bytes explicitly so serialization is host-independent.

Parameters

[out]	p	Destination spanning four bytes.
[in]	v	Value to encode.

Precondition: p is non-null and writable for four bytes.; v may be any uint32_t value.

Postcondition: Exactly four bytes contain v least-significant byte first.; No byte beyond the four-byte field is changed.

Note: Pure apart from caller output and thread-safe.

Since: 0.1.0

Definition at line 70 of file board_periph_sd_format.c.

References k_le_byte0, k_le_byte1, k_le_byte2, k_le_byte3, k_le_byte_mask, k_le_shift_b1, k_le_shift_b2, k_le_shift_b3, and RA8_INTERNAL.

Referenced by internal_fat16_write_bpb(), internal_fat32_write_bpb(), and priv_board_sd_format_fat32().

◆ internal_write_sector()

RA8_INTERNAL bool internal_write_sector	(	int	image_fd,
		uint32_t	sector,
		const uint8_t *	data )

static

Write one complete sector at its checked positioned offset.

Converts the sector number to a 64-bit byte offset and delegates exact host I/O.

Parameters

[in]	image_fd	Open sparse working-image descriptor.
[in]	sector	Zero-based sector number.
[in]	data	Source spanning exactly k_fmt_sec_bytes bytes.

Returns: Whether exact positioned I/O succeeded.

Return values

true	Complete sector was written.
false	Host positioned write failed.

Precondition: image_fd is open and writable.; data is non-null and sector lies within prepared image geometry.

Postcondition: Success replaces exactly the selected sector.; Descriptor stream position is unchanged.

Note: Not thread-safe for overlapping sector writes.

Since: 0.1.0

Definition at line 298 of file board_periph_sd_format.c.

References k_emu_io_ok, k_fmt_sec_bytes, priv_emu_io_pwrite_exact(), RA8_INTERNAL, and emu_io_result_t::status.

Referenced by priv_board_sd_format_fat16(), and priv_board_sd_format_fat32().

◆ priv_board_sd_format_fat16()

bool priv_board_sd_format_fat16	(	int	image_fd,
		uint32_t	total_sectors,
		const char *	label,
		uint32_t *	out_spc )

nodiscard

Format the attached sparse backend as a FAT16 volume.

Writes a complete BPB (boot frame, geometry, label, volume id), the signature bytes and the FAT[0]/FAT[1] reserved entries – enough to satisfy a host fsck_msdos and the firmware's ra8_fs mount alike.

Parameters

[in]	image_fd	Sized sparse backing descriptor to format.
[in]	total_sectors	Card capacity in 512-byte sectors.
[in]	label	Volume label (space-padded to 11 chars).
[out]	out_spc	Receives the selected sectors per cluster.

Returns: Whether every required sector was written exactly.

Return values

true	The empty FAT16 volume was serialized.
false	A positioned backend write failed.

Precondition: image_fd is writable and sized for total_sectors sectors.; total_sectors fits FAT16 cluster limits (caller picked FAT16).

Postcondition: The image mounts as an empty FAT16 volume.

Note: Uses only fixed one-sector buffers; not thread-safe.

Since: 0.1.0

Definition at line 306 of file board_periph_sd_format.c.

References internal_fat16_solve_geometry(), internal_fat16_write_bpb(), internal_sd_put16(), internal_write_sector(), k_bpb_dir_ent_size, k_bpb_num_fats_val, k_fat16_eoc_clus0, k_fat16_eoc_clus1, k_fat_ent1_off, k_fmt_resv_f16, k_fmt_root_ents, k_fmt_sec_bytes, and k_le_byte0.

Referenced by board_sd_attach_blank().

◆ priv_board_sd_format_fat32()

bool priv_board_sd_format_fat32	(	int	image_fd,
		uint32_t	total_sectors,
		const char *	label,
		uint32_t *	out_spc )

nodiscard

Format the attached sparse backend as a FAT32 volume.

Writes the FAT32 BPB (with FSInfo + backup boot sectors), the root-directory cluster chain and both FAT copies' reserved entries.

Parameters

[in]	image_fd	Sized sparse backing descriptor to format.
[in]	total_sectors	Card capacity in 512-byte sectors.
[in]	label	Volume label (space-padded to 11 chars).
[out]	out_spc	Receives the selected sectors per cluster.

Returns: Whether every required sector was written exactly.

Return values

true	The empty FAT32 volume was serialized.
false	A positioned backend write failed.

Precondition: image_fd is writable and sized for total_sectors sectors.; total_sectors warrants FAT32 (caller picked FAT32).

Postcondition: The image mounts as an empty FAT32 volume.

Note: Uses only fixed one-sector buffers; not thread-safe.

Since: 0.1.0

Definition at line 435 of file board_periph_sd_format.c.

References internal_fat32_write_bpb(), internal_sd_fat32_geometry(), internal_sd_put32(), internal_write_sector(), k_bpb_num_fats_val, k_fat32_bkboot_sec, k_fat32_ent1_off, k_fat32_ent2_off, k_fat32_eoc, k_fat32_eoc_media, k_fat32_fsinfo_sec, k_fmt_resv_f32, k_fmt_sec_bytes, k_fsi_free_unknown, k_fsi_lead_sig, k_fsi_nxt_free, k_fsi_off_free, k_fsi_off_lead, k_fsi_off_nxtfree, k_fsi_off_struc, k_fsi_off_trail, k_fsi_struc_sig, k_fsi_trail_sig, and k_le_byte0.

Referenced by board_sd_attach_blank().

◆ priv_board_sd_label_field()

void priv_board_sd_label_field	(	uint8_t *	dst,
		const char *	label )

Pad an ASCII volume label to the 11-byte 8.3 field (space-filled).

Copy a volume label into an 11-char space-padded 8.3 field.

Definition at line 176 of file board_periph_sd_format.c.

References k_fmt_label_len.

Referenced by board_sd_attach_blank(), internal_fat16_write_bpb(), and internal_fat32_write_bpb().

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ sd_bpb_off_t

◆ sd_bpb_val_t

◆ sd_le_const_t

Function Documentation

◆ internal_fat16_solve_geometry()

◆ internal_fat16_write_bpb()

◆ internal_fat32_write_bpb()

◆ internal_sd_boot_frame()

◆ internal_sd_fat32_geometry()

◆ internal_sd_put16()

◆ internal_sd_put32()

◆ internal_write_sector()

◆ priv_board_sd_format_fat16()

◆ priv_board_sd_format_fat32()

◆ priv_board_sd_label_field()