//硬盘数据结构初始化
void ide_init(){
printk("ide_init start\n");
uint8_t hd_cnt = *((uint8_t*)(0x475)); //获取硬盘的数量
ASSERT(hd_cnt > 0);
list_init(&partition_list);
channel_cnt = DIV_ROUND_UP(hd_cnt,2); //一个ide通道上有两个硬盘，根据硬盘数量反推有几个ide通道
struct ide_channel* channel;
uint8_t channel_no = 0,dev_no = 0;
//处理每个通道上的硬盘
while(channel_no < channel_cnt){
channel = &channels[channel_no];
sprintf(channel->name,"ide%d",channel_no);
//为每个ide通道初始化端口基址及中断向量
switch(channel_no){
case 0:
channel->port_base = 0x1f0; //ide0通道的起始端口号为0x1f0
channel->irq_no = 0x20 + 14; //从片8259a上倒数第二的中断引脚，也就是ide0通道的中断向量号
break;
case 1:
channel->port_base = 0x170; //ide1通道的起始端口号为0x170
channel->irq_no = 0x20 + 15; //从片8259a上最后一个引脚，我们用来响应ide1通道上的硬盘中断
break;
}
channel->expecting_intr = false; //为向硬盘写入指令时不期待硬盘的中断
lock_init(&channel->lock);
//初始化为0，目的是向硬盘控制器请求数据后，硬盘驱动sema_down此信号量会阻塞线程
//直到硬盘完成后通过发中断，以后中断处理程序将此信号量sema_up,唤醒线程
sema_init(&channel->disk_done,0);
register_handler(channel->irq_no,intr_hd_handler);
/* 分别获取两个硬盘的参数及分区信息 */
while (dev_no < 2) {
struct disk* hd = &channel->devices[dev_no];
hd->my_channel = channel;
hd->dev_no = dev_no;
sprintf(hd->name, "sd%c", 'a' + channel_no * 2 + dev_no);
identify_disk(hd); // 获取硬盘参数
if (dev_no != 0) { // 内核本身的裸硬盘(hd60M.img)不处理
partition_scan(hd, 0); // 扫描该硬盘上的分区
}
p_no = 0, l_no = 0;
dev_no++;
}
dev_no = 0;
channel_no++; //下一个channel
}
printk("\n all partition info\n");
/* 打印所有分区信息 */
list_traversal(&partition_list, partition_info, (int)NULL);
printk("ide_init done\n");
}
/* 扫描硬盘hd中地址为ext_lba的扇区中的所有分区 */
static void partition_scan(struct disk* hd, uint32_t ext_lba) {
struct boot_sector* bs = sys_malloc(sizeof(struct boot_sector));
ide_read(hd, ext_lba, bs, 1);
uint8_t part_idx = 0;
struct partition_table_entry* p = bs->partition_table;
/* 遍历分区表4个分区表项 */
while (part_idx++ < 4) {
if (p->fs_type == 0x5) { // 若为扩展分区
if (ext_lba_base != 0) {
/* 子扩展分区的start_lba是相对于主引导扇区中的总扩展分区地址 */
partition_scan(hd, p->start_lba + ext_lba_base);
} else { // ext_lba_base为0表示是第一次读取引导块,也就是主引导记录所在的扇区
/* 记录下扩展分区的起始lba地址,后面所有的扩展分区地址都相对于此 */
ext_lba_base = p->start_lba;
partition_scan(hd, p->start_lba);
}
} else if (p->fs_type != 0) { // 若是有效的分区类型
if (ext_lba == 0) { // 此时全是主分区
hd->prim_parts[p_no].start_lba = ext_lba + p->start_lba;
hd->prim_parts[p_no].sec_cnt = p->sec_cnt;
hd->prim_parts[p_no].my_disk = hd;
list_append(&partition_list, &hd->prim_parts[p_no].part_tag);
sprintf(hd->prim_parts[p_no].name, "%s%d", hd->name, p_no + 1);
p_no++;
ASSERT(p_no < 4); // 0,1,2,3
} else {
hd->logic_parts[l_no].start_lba = ext_lba + p->start_lba;
hd->logic_parts[l_no].sec_cnt = p->sec_cnt;
hd->logic_parts[l_no].my_disk = hd;
list_append(&partition_list, &hd->logic_parts[l_no].part_tag);
sprintf(hd->logic_parts[l_no].name, "%s%d", hd->name, l_no + 5); // 逻辑分区数字是从5开始,主分区是1～4.
l_no++;
if (l_no >= 8) // 只支持8个逻辑分区,避免数组越界
return;
}
}
p++;
}
sys_free(bs);
}
/* load the (virtual) file system */
int init_vfs()
{
/* TODO: scan all drives */
if (drive[0].exists == 1)
{
/* needed for readblock to function. Should figure out this mess, maybe readblock should take these parameters? */
ata_drsel(ATA_PRI_DATAPORT, MASTER_HD);
partition_scan(&drive[0]);
fat_scan(&drive[0].part[0]);
}
return 1;
}
