/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/adfs_fs.h>

/* Internal data structures for ADFS */

#define ADFS_FREE_FRAG           0
#define ADFS_BAD_FRAG            1
#define ADFS_ROOT_FRAG           2

#define ADFS_FILETYPE_NONE      ((u16)~0)

/* RISC OS 12-bit filetype is stored in load_address[19:8] */
static inline u16 adfs_filetype(u32 loadaddr)
{
        return (loadaddr & 0xfff00000) == 0xfff00000 ?
               (loadaddr >> 8) & 0xfff : ADFS_FILETYPE_NONE;
}

#define ADFS_NDA_OWNER_READ     (1 << 0)
#define ADFS_NDA_OWNER_WRITE    (1 << 1)
#define ADFS_NDA_LOCKED         (1 << 2)
#define ADFS_NDA_DIRECTORY      (1 << 3)
#define ADFS_NDA_EXECUTE        (1 << 4)
#define ADFS_NDA_PUBLIC_READ    (1 << 5)
#define ADFS_NDA_PUBLIC_WRITE   (1 << 6)

/*
 * adfs file system inode data in memory
 */
struct adfs_inode_info {
        loff_t          mmu_private;
        __u32           parent_id;      /* parent indirect disc address */
        __u32           indaddr;        /* object indirect disc address */
        __u32           loadaddr;       /* RISC OS load address         */
        __u32           execaddr;       /* RISC OS exec address         */
        unsigned int    attr;           /* RISC OS permissions          */
        struct inode vfs_inode;
};

static inline struct adfs_inode_info *ADFS_I(struct inode *inode)
{
        return container_of(inode, struct adfs_inode_info, vfs_inode);
}

static inline bool adfs_inode_is_stamped(struct inode *inode)
{
        return (ADFS_I(inode)->loadaddr & 0xfff00000) == 0xfff00000;
}

/*
 * Forward-declare this
 */
struct adfs_discmap;
struct adfs_dir_ops;

/*
 * ADFS file system superblock data in memory
 */
struct adfs_sb_info {
        union { struct {
                struct adfs_discmap *s_map;     /* bh list containing map */
                const struct adfs_dir_ops *s_dir; /* directory operations */
                };
                struct rcu_head rcu;    /* used only at shutdown time    */
        };
        kuid_t          s_uid;          /* owner uid */
        kgid_t          s_gid;          /* owner gid */
        umode_t         s_owner_mask;   /* ADFS owner perm -> unix perm */
        umode_t         s_other_mask;   /* ADFS other perm -> unix perm */
        int             s_ftsuffix;     /* ,xyz hex filetype suffix option */

        __u32           s_ids_per_zone; /* max. no ids in one zone */
        __u32           s_idlen;        /* length of ID in map */
        __u32           s_map_size;     /* sector size of a map */
        signed int      s_map2blk;      /* shift left by this for map->sector*/
        unsigned int    s_log2sharesize;/* log2 share size */
        unsigned int    s_namelen;      /* maximum number of characters in name  */
};

static inline struct adfs_sb_info *ADFS_SB(struct super_block *sb)
{
        return sb->s_fs_info;
}

/*
 * Directory handling
 */
struct adfs_dir {
        struct super_block      *sb;

        int                     nr_buffers;
        struct buffer_head      *bh[4];
        struct buffer_head      **bhs;

        unsigned int            pos;
        __u32                   parent_id;

        union {
                struct adfs_dirheader   *dirhead;
                struct adfs_bigdirheader *bighead;
        };
        union {
                struct adfs_newdirtail  *newtail;
                struct adfs_bigdirtail  *bigtail;
        };
};

/*
 * This is the overall maximum name length
 */
#define ADFS_MAX_NAME_LEN       (256 + 4) /* +4 for ,xyz hex filetype suffix */
struct object_info {
        __u32           parent_id;              /* parent object id     */
        __u32           indaddr;                /* indirect disc addr   */
        __u32           loadaddr;               /* load address         */
        __u32           execaddr;               /* execution address    */
        __u32           size;                   /* size                 */
        __u8            attr;                   /* RISC OS attributes   */
        unsigned int    name_len;               /* name length          */
        char            name[ADFS_MAX_NAME_LEN];/* file name            */
};

struct adfs_dir_ops {
        int     (*read)(struct super_block *sb, unsigned int indaddr,
                        unsigned int size, struct adfs_dir *dir);
        int     (*iterate)(struct adfs_dir *dir, struct dir_context *ctx);
        int     (*setpos)(struct adfs_dir *dir, unsigned int fpos);
        int     (*getnext)(struct adfs_dir *dir, struct object_info *obj);
        int     (*update)(struct adfs_dir *dir, struct object_info *obj);
        int     (*create)(struct adfs_dir *dir, struct object_info *obj);
        int     (*remove)(struct adfs_dir *dir, struct object_info *obj);
        int     (*commit)(struct adfs_dir *dir);
};

struct adfs_discmap {
        struct buffer_head      *dm_bh;
        __u32                   dm_startblk;
        unsigned int            dm_startbit;
        unsigned int            dm_endbit;
};

/* Inode stuff */
struct inode *adfs_iget(struct super_block *sb, struct object_info *obj);
int adfs_write_inode(struct inode *inode, struct writeback_control *wbc);
int adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
                       struct iattr *attr);

/* map.c */
int adfs_map_lookup(struct super_block *sb, u32 frag_id, unsigned int offset);
void adfs_map_statfs(struct super_block *sb, struct kstatfs *buf);
struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr);
void adfs_free_map(struct super_block *sb);

/* Misc */
__printf(3, 4)
void __adfs_error(struct super_block *sb, const char *function,
                  const char *fmt, ...);
#define adfs_error(sb, fmt...) __adfs_error(sb, __func__, fmt)
void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...);

/* super.c */

/*
 * Inodes and file operations
 */

/* dir_*.c */
extern const struct inode_operations adfs_dir_inode_operations;
extern const struct file_operations adfs_dir_operations;
extern const struct dentry_operations adfs_dentry_operations;
extern const struct adfs_dir_ops adfs_f_dir_ops;
extern const struct adfs_dir_ops adfs_fplus_dir_ops;

int adfs_dir_copyfrom(void *dst, struct adfs_dir *dir, unsigned int offset,
                      size_t len);
int adfs_dir_copyto(struct adfs_dir *dir, unsigned int offset, const void *src,
                    size_t len);
void adfs_dir_relse(struct adfs_dir *dir);
int adfs_dir_read_buffers(struct super_block *sb, u32 indaddr,
                          unsigned int size, struct adfs_dir *dir);
void adfs_object_fixup(struct adfs_dir *dir, struct object_info *obj);
extern int adfs_dir_update(struct super_block *sb, struct object_info *obj,
                           int wait);

/* file.c */
extern const struct inode_operations adfs_file_inode_operations;
extern const struct file_operations adfs_file_operations;

static inline __u32 signed_asl(__u32 val, signed int shift)
{
        if (shift >= 0)
                val <<= shift;
        else
                val >>= -shift;
        return val;
}

/*
 * Calculate the address of a block in an object given the block offset
 * and the object identity.
 *
 * The root directory ID should always be looked up in the map [3.4]
 */
static inline int __adfs_block_map(struct super_block *sb, u32 indaddr,
                                   unsigned int block)
{
        if (indaddr & 255) {
                unsigned int off;

                off = (indaddr & 255) - 1;
                block += off << ADFS_SB(sb)->s_log2sharesize;
        }

        return adfs_map_lookup(sb, indaddr >> 8, block);
}

/* Return the disc record from the map */
static inline
struct adfs_discrecord *adfs_map_discrecord(struct adfs_discmap *dm)
{
        return (void *)(dm[0].dm_bh->b_data + 4);
}

static inline u64 adfs_disc_size(const struct adfs_discrecord *dr)
{
        return (u64)le32_to_cpu(dr->disc_size_high) << 32 |
                    le32_to_cpu(dr->disc_size);
}