114 lines
3.3 KiB
C
114 lines
3.3 KiB
C
// SPDX-License-Identifier: MIT
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//
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// kernel/device.h
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// Driver declarations.
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//
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// Copyright © 2024 Kyle J Cardoza <Kyle.Cardoza@icloud.com>
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#pragma once
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#ifdef __CALYPSI_CC__
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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// This symbol determines the maximum number of device drivers which
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// can be in memory.
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#ifndef DEVICE_MAX
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#define DEVICE_MAX 32
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#endif
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// This symbol determines the maximum number of device map entries which
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// ca be in memory.
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#ifndef DEVICE_MAP_MAX
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#define DEVICE_MAP_MAX 32
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#endif
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// Forward declaration.
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struct file;
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// A device, in this context, is a code module which exposes a defined set
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// of functions for interacting with files and file-like data. It is not specific
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// as to the nature of the underlying data storage. It is equally valid for a
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// device to use a block of RAM or a serial device as it is a hard drive
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// or SD card.
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//
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// None of these functions are required to actually do anyting if it is not
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// sensible for the kind of device being used; for example, it is not
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// sensible for an inherently read-only device to support moving or
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// renaming files.
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typedef struct {
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// Initialize the device.
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int (*init)(void);
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// Opens a file, given a pathname.
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int (*open)(struct file *file);
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// Closes an open file, given a unique ID.
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int (*close)(struct file *file);
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// Seeks within an open file, given a unique ID and a length.
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int (*seek)(struct file *file, long length);
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// Reads data from the specified file.
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int (*read)(struct file *file, void *dest, size_t length);
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// Writes data to the specified file.
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int (*write)(struct file *file, void *src, size_t length);
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// Perform driver-specific operations.
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int (*ioctl)(struct file *file,
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unsigned short operation,
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void *arg);
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// Creates the specified file given a pathname.
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int (*create)(struct file *file);
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// Copies the specified file using the specified names.
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int (*copy)(struct file *src,
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struct file *dest);
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// Moves the specified file using the specified names.
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int (*move)(struct file *src,
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struct file *dest);
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// Gets the size of the file.
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int (*get_file_size)(struct file *file, size_t *size);
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// Fills out the metadata in the specified file from the pathname
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// in the provided file.
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int (*init_file)(struct file *file);
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} Device;
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// The device map is a table that maps device names, such as SD0: or
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// TTY2: to the device driver that manages the device.
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struct device_map {
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char *name;
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unsigned short major_number;
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unsigned short minor_number;
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};
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// The global table of device drivers.
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extern Device *device[DEVICE_MAX];
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// The global map of device names to device modules.
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extern struct device_map *device_map[DEVICE_MAP_MAX];
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// Initialize all the device drivers. This is called once, at boot.
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// It protects itself against being called again without a reset.
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void device_init_all(void);
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// Binds a device name to a device.
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int device_bind_name(char *name,
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unsigned short major_number,
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unsigned short minor_number);
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// Unbinds a bound device name.
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int device_unbind_name(char *name);
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// Get a bound device by its name.
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int device_get_by_name(char *name, Device **device);
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#endif
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