fs read/write functions, initrd

7 files changed, 202 insertions, 28 deletions

diff --git a/kernel/entry.S b/kernel/entry.S
index e1b4767..aa4c38d 100644
--- a/kernel/entry.S
+++ b/kernel/entry.S
@@ -26,6 +26,7 @@ mb_start:
 	.short 1
 	.long 36
 	.long 1 # cmdline
+	.long 3 # module
 	.long 6 # mmap
 	.long 9 # elf section
 	.long 12 # efi64
@@ -46,6 +47,11 @@ mb_start:
 	.long 720 # width
 	.long 480 # height
 	.long 32 # bpp
+	# module align
+	.align 8
+	.short 6
+	.short 0
+	.long 8
 	# efi boot services
 	.align 8
 	.short 7
diff --git a/kernel/fs/fs.c b/kernel/fs/fs.c
index 4682e41..4b6bc5d 100644
--- a/kernel/fs/fs.c
+++ b/kernel/fs/fs.c
@@ -1,18 +1,49 @@
 #include <lib.h>
 #include <comus/fs.h>
+#include <comus/mboot.h>
 
-struct disk fs_disks[MAX_DISKS];
-struct file_system fs_loaded_file_systems[MAX_DISKS];
+struct disk fs_disks[N_DISKS];
+struct file_system fs_loaded_file_systems[N_DISKS];
 
 void fs_init(void)
 {
+	size_t idx = 0;
+
 	// zero structures
 	memsetv(fs_disks, 0, sizeof(fs_disks));
 	memsetv(fs_loaded_file_systems, 0, sizeof(fs_loaded_file_systems));
 
-	// TODO: go though ide and/or sata drivers to load all disks into `fs_disks` structures
+	// check for initrd
+	size_t rd_len;
+	void *rd = mboot_get_initrd(&rd_len);
+	if (rd != NULL) {
+		assert(idx < N_DISKS, "Too many disks, limit is: %d\n", N_DISKS);
+		fs_disks[idx] = (struct disk) {
+			.present = 1,
+			.id = idx,
+			.type = DISK_TYPE_RAMDISK,
+			.rd.start = rd,
+			.rd.len = rd_len,
+		};
+		idx++;
+	}
+
+	// check for ide/ata devices
+	struct ide_devicelist ide_list = ide_devices_enumerate();
+	for (size_t i = 0; i < ide_list.num_devices; i++) {
+		assert(idx < N_DISKS, "Too many disks, limit is: %d\n", N_DISKS);
+		fs_disks[idx] = (struct disk) {
+			.present = 1,
+			.id = idx,
+			.type = DISK_TYPE_ATA,
+			.ide = ide_list.devices[i],
+		};
+		idx++;
+	}
+
+	INFO("loaded %zu disks\n", idx);
 
-	// TODO: go though each disk and attempt to load a file system
+	// TODO: load filesystems on disks
 }
 
 struct disk *fs_get_root_disk(void)
@@ -20,7 +51,7 @@ struct disk *fs_get_root_disk(void)
 	// NOTE: currently im just getting the first disk
 	// found, is this fine?
 
-	for (int i = 0; i < MAX_DISKS; i++) {
+	for (int i = 0; i < N_DISKS; i++) {
 		struct disk *disk = &fs_disks[i];
 		if (disk->present)
 			return disk;
@@ -34,7 +65,7 @@ struct file_system *fs_get_root_file_system(void)
 	// NOTE: currently im just getting the first file system
 	// found, is this fine?
 
-	for (int i = 0; i < MAX_DISKS; i++) {
+	for (int i = 0; i < N_DISKS; i++) {
 		struct file_system *fs = &fs_loaded_file_systems[i];
 		if (fs->present)
 			return fs;
@@ -61,22 +92,117 @@ int fs_find_file_rel(struct file *rel, char *rel_path, struct file *res)
 	panic("fs_find_file_rel NOT YET IMPLEMENTED");
 }
 
+static int disk_read_rd(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
+{
+	if (offset + len >= disk->rd.len) {
+		WARN("attempted to read past length of ramdisk");
+		return 1;
+	}
+
+	memcpy(buffer, disk->rd.start + offset, len);
+	return 0;
+}
+
+static int disk_read_ata(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
+{
+	static size_t atabuf_len = 0;
+	static uint16_t *atabuf = NULL;
+
+	uint32_t numsects = (len + ATA_SECT_SIZE - 1) / ATA_SECT_SIZE;
+	uint32_t err = offset % ATA_SECT_SIZE;
+	int ret = 0;
+
+	if (atabuf == NULL || atabuf_len < numsects*ATA_SECT_SIZE) {
+		if ((atabuf = krealloc(atabuf, numsects*ATA_SECT_SIZE)) == NULL)
+			return 1;
+		atabuf_len = numsects*ATA_SECT_SIZE;
+	}
+
+	// read sectors
+	if ((ret = ide_device_read_sectors(disk->ide, numsects, offset / ATA_SECT_SIZE, atabuf)))
+		return 1;
+
+	// copy over to buffer
+	memcpy(buffer, atabuf + err, len);
+
+	return ret;
+}
+
+
 int disk_read(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
 {
-	(void)disk;
-	(void)offset;
-	(void)len;
-	(void)buffer;
+	int ret = 0;
 
-	panic("disk_read NOT YET IMPLEMENTED");
+	switch(disk->type) {
+	case DISK_TYPE_RAMDISK:
+		ret = disk_read_rd(disk, offset, len, buffer);
+		break;
+	case DISK_TYPE_ATA:
+		ret = disk_read_ata(disk, offset, len, buffer);
+		break;
+	default:
+		ERROR("attempted to read from disk with invalid type: %d\n", disk->type);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+static int disk_write_rd(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
+{
+	if (offset + len >= disk->rd.len) {
+		WARN("attempted to write past length of ramdisk");
+		return 1;
+	}
+
+	memcpy(disk->rd.start + offset, buffer, len);
+	return 0;
+}
+
+static int disk_write_ata(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
+{
+	static size_t atabuf_len = 0;
+	static uint16_t *atabuf = NULL;
+
+	uint32_t numsects = (len + ATA_SECT_SIZE - 1) / ATA_SECT_SIZE;
+	uint32_t err = offset % ATA_SECT_SIZE;
+	int ret = 0;
+
+	if (atabuf == NULL || atabuf_len < numsects*ATA_SECT_SIZE) {
+		if ((atabuf = krealloc(atabuf, numsects*ATA_SECT_SIZE)) == NULL)
+			return 1;
+		atabuf_len = numsects*ATA_SECT_SIZE;
+	}
+
+	// read sectors what will be overwritten
+	if ((ret = ide_device_read_sectors(disk->ide, numsects, offset / ATA_SECT_SIZE, atabuf)))
+		return 1;
+
+	// copy custom data over
+	memcpy(atabuf + err, buffer, len);
+
+	// write back sectors
+	if ((ret = ide_device_write_sectors(disk->ide, numsects, offset / ATA_SECT_SIZE, atabuf)))
+		return 1;
+
+	return ret;
 }
 
 int disk_write(struct disk *disk, size_t offset, size_t len, uint8_t *buffer)
 {
-	(void)disk;
-	(void)offset;
-	(void)len;
-	(void)buffer;
+	int ret = 0;
+
+	switch(disk->type) {
+	case DISK_TYPE_RAMDISK:
+		ret = disk_write_rd(disk, offset, len, buffer);
+		break;
+	case DISK_TYPE_ATA:
+		ret = disk_write_ata(disk, offset, len, buffer);
+		break;
+	default:
+		ERROR("attempted to write to disk with invalid type: %d\n", disk->type);
+		ret = 1;
+	}
 
-	panic("disk_write NOT YET IMPLEMENTED");
+	return ret;
 }
diff --git a/kernel/include/comus/drivers/ata.h b/kernel/include/comus/drivers/ata.h
index 66b3ba5..2f35e03 100644
--- a/kernel/include/comus/drivers/ata.h
+++ b/kernel/include/comus/drivers/ata.h
@@ -10,6 +10,8 @@
 #ifndef ATA_H_
 #define ATA_H_
 
+#define ATA_SECT_SIZE 512
+
 #include <stdint.h>
 #include <stdbool.h>
 
diff --git a/kernel/include/comus/fs.h b/kernel/include/comus/fs.h
index fe335ca..048c7c5 100644
--- a/kernel/include/comus/fs.h
+++ b/kernel/include/comus/fs.h
@@ -11,10 +11,13 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <comus/limits.h>
+#include <comus/drivers/ata.h>
 
-// FIXME: aaaa
-#define MAX_DISKS 8
-#define MAX_FILE_NAME_LEN 256
+enum disk_type {
+	DISK_TYPE_ATA,
+	DISK_TYPE_RAMDISK,
+};
 
 struct disk {
 	/// set to 1 in array to state that fs is defined
@@ -23,12 +26,16 @@ struct disk {
 	/// index into disks array
 	/// system use only
 	int id;
-	/// TODO: pci? inb/outb?
-	/// we need a structure to access disks and how to define them
-	/// IDE / SATA / .... ???
-	/// we should probable create ide_disk, or sata_disk, and so on
-	/// then convert this part to a union with a tag specifier
-	/// we then need drivers for ide and/or sata, ide is easier
+	/// disk type
+	enum disk_type type;
+	/// internal disk device
+	union {
+		struct {
+			char *start;
+			size_t len;
+		} rd;
+		ide_device_t ide;
+	};
 };
 
 /**
@@ -67,7 +74,7 @@ enum file_type {
 
 struct file {
 	/// name of the file
-	char name[MAX_FILE_NAME_LEN];
+	char name[N_FILE_NAME];
 	/// parent directory of the file
 	struct file_s *parent;
 	/// type of the file
@@ -159,10 +166,10 @@ struct file_system {
 };
 
 // list of all disks on the system
-extern struct disk fs_disks[MAX_DISKS];
+extern struct disk fs_disks[N_DISKS];
 
 // list of all loaded file systems for each disk
-extern struct file_system fs_loaded_file_systems[MAX_DISKS];
+extern struct file_system fs_loaded_file_systems[N_DISKS];
 
 /**
  * Initalize file system structures
diff --git a/kernel/include/comus/limits.h b/kernel/include/comus/limits.h
index b6c596b..675df47 100644
--- a/kernel/include/comus/limits.h
+++ b/kernel/include/comus/limits.h
@@ -18,6 +18,10 @@
 /// max memory entires
 #define N_MMAP_ENTRY 256
 
+/// max fs limits
+#define N_FILE_NAME 256
+#define N_DISKS 8
+
 /// length of terminal buffer
 #define TERM_MAX_WIDTH 1920
 #define TERM_MAX_HEIGHT 1080
diff --git a/kernel/include/comus/mboot.h b/kernel/include/comus/mboot.h
index 036cc40..aba3e4e 100644
--- a/kernel/include/comus/mboot.h
+++ b/kernel/include/comus/mboot.h
@@ -42,4 +42,9 @@ EFI_SYSTEM_TABLE *mboot_get_efi_st(void);
  */
 EFI_HANDLE mboot_get_efi_hdl(void);
 
+/**
+ * Returns the pointer to the loaded init ram disk with size given by len
+ */
+void *mboot_get_initrd(size_t *len);
+
 #endif /* mboot.h */
diff --git a/kernel/mboot/module.c b/kernel/mboot/module.c
new file mode 100644
index 0000000..7a64f2e
--- /dev/null
+++ b/kernel/mboot/module.c
@@ -0,0 +1,24 @@
+#include <comus/mboot.h>
+
+#include "mboot.h"
+
+#define MULTIBOOT_TAG_TYPE_MODULE 3
+
+struct multiboot_tag_module {
+	uint32_t type;
+	uint32_t size;
+	uint32_t mod_start;
+	uint32_t mod_end;
+	char cmdline[];
+};
+
+void *mboot_get_initrd(size_t *len)
+{
+	void *tag = locate_mboot_table(MULTIBOOT_TAG_TYPE_MODULE);
+	if (tag == NULL)
+		return NULL;
+
+	struct multiboot_tag_module *mod = (struct multiboot_tag_module *)tag;
+	*len = mod->mod_end - mod->mod_start;
+	return (void*) (uintptr_t) mod->mod_start;
+}