refactor

.gitignore

@@ -7,4 +7,6 @@
 *.bak
 bak
 .vscode
+*.img
+*.dsk
 

08-BlockDeviceDriver/Makefile

@@ -18,12 +18,12 @@ string.c
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 4 -machine virt -bios none
-QFLAGS += -drive file=fs.img,if=none,format=raw,id=x0
+QFLAGS += -drive if=none,format=raw,file=hdd.dsk,id=x0
 QFLAGS += -device virtio-blk-device,drive=x0,bus=virtio-mmio-bus.0
 
 OBJDUMP = riscv64-unknown-elf-objdump
 
-all: os.elf
+all: clean os.elf hdd.dsk qemu
 
 os.elf: $(OBJ)
 	$(CC) $(CFLAGS) -T os.ld -o os.elf $^
@@ -34,10 +34,10 @@ qemu: $(TARGET)
 	$(QEMU) $(QFLAGS) -kernel os.elf
 
 clean:
-	rm -f *.elf
+	rm -f *.elf *.img *.dsk
 
-fs.img:
+hdd.dsk:
-	qemu-img create -f raw fs.img 50M
+	dd if=/dev/urandom of=hdd.dsk bs=1M count=32
 
 .PHONY : debug
 debug: all

08-BlockDeviceDriver/os.c

@@ -19,12 +19,13 @@ void os_start()
 {
 	uart_init();
 	lib_puts("OS start\n");
-	virtio_disk_init();
 	user_init();
 	trap_init();
 	plic_init();
+	virtio_disk_init();
 	timer_init(); // start timer interrupt ...
-	virtio_tester();
+	virtio_tester(1);
+	virtio_tester(0);
 }
 
 int os_main(void)

08-BlockDeviceDriver/plic.c

@@ -2,7 +2,7 @@
 
 // ref: https://github.com/qemu/qemu/blob/master/include/hw/riscv/virt.h
 // Intro: https://github.com/ianchen0119/AwesomeCS/wiki/2-5-RISC-V::%E4%B8%AD%E6%96%B7%E8%88%87%E7%95%B0%E5%B8%B8%E8%99%95%E7%90%86----PLIC-%E4%BB%8B%E7%B4%B9
-#define PLIC_BASE 0x0c000000L
+#define PLIC_BASE 0x0c000000
 #define PLIC_PRIORITY(id) (PLIC_BASE + (id)*4)
 #define PLIC_PENDING(id) (PLIC_BASE + 0x1000 + ((id) / 32))
 #define PLIC_MENABLE(hart) (PLIC_BASE + 0x2000 + (hart)*0x80)
@@ -15,10 +15,16 @@ void plic_init()
   int hart = r_tp();
   // QEMU Virt machine support 7 priority (1 - 7),
   // The "0" is reserved, and the lowest priority is "1".
-  *(uint32_t *)PLIC_PRIORITY(UART0_IRQ) = 1;
+  for (size_t i = VIRTIO_IRQ; i <= UART0_IRQ; i++)
+  {
+    *(uint32_t *)PLIC_PRIORITY(i) = 1;
+  }
 
-  /* Enable UART0 */
+  /* Enable UART0 and VIRTIO */
-  *(uint32_t *)PLIC_MENABLE(hart) = (1 << UART0_IRQ);
+  for (size_t i = VIRTIO_IRQ; i <= UART0_IRQ; i++)
+  {
+    *(uint32_t *)PLIC_MENABLE(hart) |= (1 << i);
+  }
 
   /* Set priority threshold for UART0. */
 

08-BlockDeviceDriver/trap.c

@@ -14,8 +14,9 @@ void external_handler()
   {
     lib_isr();
   }
-  else if (irq == VIRTIO_IRQ)
+  else if (0 < irq < 9)
   {
+    panic("Virio IRQ");
     virtio_disk_isr();
   }
   else if (irq)
@@ -63,7 +64,7 @@ reg_t trap_handler(reg_t epc, reg_t cause)
   else
   {
     /* Synchronous trap - exception */
-    lib_puts("Sync exceptions!\n");
+    lib_printf("Sync exceptions! cause code: %d\n", cause_code);
     while (1)
     {
       /* code */

08-BlockDeviceDriver/types.h

@@ -1,13 +1,12 @@
 #ifndef __TYPES_H__
 #define __TYPES_H__
 
-typedef signed char int8;
+typedef unsigned int uint;
+typedef unsigned short ushort;
+typedef unsigned char uchar;
+
 typedef unsigned char uint8;
-typedef short int16;
 typedef unsigned short uint16;
-typedef int int32;
+typedef unsigned int uint32;
-typedef unsigned uint32;
-typedef long long int64;
-typedef unsigned long long uint64;
 
 #endif

08-BlockDeviceDriver/user.c

@@ -53,8 +53,6 @@ void user_task3(void)
 	}
 }
 
-extern virtio_tester();
-
 void user_init()
 {
 	// lock_init(&lock);

08-BlockDeviceDriver/virtio.c

@@ -5,30 +5,15 @@
 #define BSIZE 1024 // block size
 #define PGSHIFT 12
 
-struct buf
+struct blk
 {
-  int valid; // has data been read from disk?
-  int disk;  // does disk "own" buf?
   uint32 dev;
   uint32 blockno;
   lock_t lock;
   uint32 refcnt;
-  struct buf *prev; // LRU cache list
-  struct buf *next;
   unsigned char data[BSIZE];
 };
 
-struct
-{
-  lock_t lock;
-  struct buf buf[30];
-
-  // Linked list of all buffers, through prev/next.
-  // Sorted by how recently the buffer was used.
-  // head.next is most recent, head.prev is least.
-  struct buf head;
-} bcache;
-
 static struct disk
 {
   char pages[2 * PGSIZE];
@@ -42,7 +27,7 @@ static struct disk
   char free[NUM];
   struct
   {
-    struct buf *b;
+    struct blk *b;
     char status;
   } info[NUM];
   uint16 used_idx;
@@ -52,38 +37,51 @@ static struct disk
   struct lock vdisk_lock;
 } __attribute__((aligned(PGSIZE))) disk;
 
-void virtio_tester()
+struct blk b[3];
+
+void virtio_tester(int write)
 {
-  // int valid; // has data been read from disk?
+  if (!b[0].dev)
-  // int disk;  // does disk "own" buf?
-  // uint32 dev;
-  // uint32 blockno;
-  // lock_t lock;
-  // uint32 refcnt;
-  // struct buf *prev; // LRU cache list
-  // struct buf *next;
-  // unsigned char data[BSIZE];
-  struct buf b[3];
-  lib_puts("buffer init...\n");
-  for (size_t i = 0; i < 3; i++)
   {
-    b[i].valid = 1;
+    lib_puts("buffer init...\n");
-    b[i].disk = 1;
+    for (size_t i = 0; i < 1; i++)
-    b[i].dev = 1;
+    {
-    b[i].blockno = i;
+      b[i].dev = 1; // always is 1
+      b[i].blockno = i + 1;
       for (size_t j = 0; j < BSIZE; j++)
       {
-      b[i].data[j] = (j + i + 1) % 10;
+        b[i].data[j] = 0;
       }
 
       lock_init(&(b[i].lock));
     }
-  lib_puts("buffer write...\n");
-  for (size_t i = 0; i < 3; i++)
-  {
-    virtio_disk_rw(&b[i], 1);
   }
-  lib_puts("wait...\n");
+
+  if (write)
+  {
+    for (size_t j = 0; j < BSIZE; j++)
+    {
+      b[0].data[j] = (j + 1) % 10;
+    }
+    lib_puts("block write...\n");
+    virtio_disk_rw(&b[0], write);
+    lib_puts("done...!\n");
+  }
+  else
+  {
+    for (size_t j = 0; j < BSIZE; j++)
+    {
+      b[0].data[j] = 0;
+    }
+    lib_puts("block read...\n");
+    virtio_disk_rw(&b[0], write);
+    size_t i = 0;
+    for (; i < 10; i++)
+    {
+      lib_printf("%d ", b[0].data[i]);
+    }
+    lib_puts("\n");
+  }
 }
 
 void virtio_disk_init()
@@ -99,6 +97,8 @@ void virtio_disk_init()
   {
     panic("could not find virtio disk");
   }
+  /* Reset the device */
+  *R(VIRTIO_MMIO_STATUS) = status;
   /* Set the ACKNOWLEDGE status bit to the status register. */
   status |= VIRTIO_CONFIG_S_ACKNOWLEDGE;
   *R(VIRTIO_MMIO_STATUS) = status;
@@ -106,7 +106,7 @@ void virtio_disk_init()
   status |= VIRTIO_CONFIG_S_DRIVER;
   *R(VIRTIO_MMIO_STATUS) = status;
   /* negotiate features */
-  uint64 features = *R(VIRTIO_MMIO_DEVICE_FEATURES);
+  uint32 features = *R(VIRTIO_MMIO_DEVICE_FEATURES);
   features &= ~(1 << VIRTIO_BLK_F_RO);
   features &= ~(1 << VIRTIO_BLK_F_SCSI);
   features &= ~(1 << VIRTIO_BLK_F_CONFIG_WCE);
@@ -129,12 +129,12 @@ void virtio_disk_init()
   *R(VIRTIO_MMIO_QUEUE_SEL) = 0;
   uint32 max = *R(VIRTIO_MMIO_QUEUE_NUM_MAX);
   if (max == 0)
-    lib_puts("virtio disk has no queue 0\n");
+    panic("virtio disk has no queue 0\n");
   if (max < NUM)
-    lib_puts("virtio disk max queue too short\n");
+    panic("virtio disk max queue too short\n");
   *R(VIRTIO_MMIO_QUEUE_NUM) = NUM;
   memset(disk.pages, 0, sizeof(disk.pages));
-  *R(VIRTIO_MMIO_QUEUE_PFN) = ((uint64)disk.pages) >> PGSHIFT;
+  *R(VIRTIO_MMIO_QUEUE_PFN) = ((uint32)disk.pages) >> PGSHIFT;
 
   // desc = pages -- num * virtq_desc
   // avail = pages + 0x40 -- 2 * uint16, then num * uint16
@@ -214,18 +214,11 @@ alloc3_desc(int *idx)
   return 0;
 }
 
-void virtio_disk_rw(struct buf *b, int write)
+void virtio_disk_rw(struct blk *b, int write)
 {
-  uint64 sector = b->blockno * (BSIZE / 512);
+  uint32 sector = b->blockno * (BSIZE / 512);
-
-  lock_acquire(&disk.vdisk_lock);
-
-  // the spec's Section 5.2 says that legacy block operations use
-  // three descriptors: one for type/reserved/sector, one for the
-  // data, one for a 1-byte status result.
 
   // allocate the three descriptors.
-  lib_puts("rw init...\n");
   int idx[3];
   while (1)
   {
@@ -244,15 +237,15 @@ void virtio_disk_rw(struct buf *b, int write)
     buf0->type = VIRTIO_BLK_T_OUT; // write the disk
   else
     buf0->type = VIRTIO_BLK_T_IN; // read the disk
-  buf0->reserved = 0;             // The reserved portion is used to pad the header to 16 bytes and move the 64-bit sector field to the correct place.
+  buf0->reserved = 0;             // The reserved portion is used to pad the header to 16 bytes and move the 32-bit sector field to the correct place.
   buf0->sector = sector;          // specify the sector that we wanna modified.
 
-  disk.desc[idx[0]].addr = (uint64)buf0;
+  disk.desc[idx[0]].addr = (uint32)buf0;
   disk.desc[idx[0]].len = sizeof(struct virtio_blk_req);
   disk.desc[idx[0]].flags = VRING_DESC_F_NEXT;
   disk.desc[idx[0]].next = idx[1];
 
-  disk.desc[idx[1]].addr = (uint64)b->data;
+  disk.desc[idx[1]].addr = (uint32)b->data;
   disk.desc[idx[1]].len = BSIZE;
   if (write)
     disk.desc[idx[1]].flags = 0; // device reads b->data
@@ -262,36 +255,27 @@ void virtio_disk_rw(struct buf *b, int write)
   disk.desc[idx[1]].next = idx[2];
 
   disk.info[idx[0]].status = 0xff; // device writes 0 on success
-  disk.desc[idx[2]].addr = (uint64)&disk.info[idx[0]].status;
+  disk.desc[idx[2]].addr = (uint32)&disk.info[idx[0]].status;
   disk.desc[idx[2]].len = 1;
   disk.desc[idx[2]].flags = VRING_DESC_F_WRITE; // device writes the status
   disk.desc[idx[2]].next = 0;
 
   // record struct buf for virtio_disk_intr().
-  b->disk = 1;
   disk.info[idx[0]].b = b;
 
+  __sync_synchronize();
+
   // tell the device the first index in our chain of descriptors.
   disk.avail->ring[disk.avail->idx % NUM] = idx[0];
-  lib_puts("rw wait...\n");
+
   __sync_synchronize();
 
   // tell the device another avail ring entry is available.
   disk.avail->idx += 1; // not % NUM ...
 
-  __sync_synchronize();
+  *R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // The device starts immediately when we write 0 to queue_notify.
-
-  *R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // value is queue number
-
-  // Wait for virtio_disk_intr() to say request has finished.
-  // while (b->disk == 1)
-  // {
-  // }
 
   disk.info[idx[0]].b = 0;
-  free_chain(idx[0]);
-
-  lock_free(&disk.vdisk_lock);
 }
 
 void virtio_disk_isr()
@@ -319,8 +303,7 @@ void virtio_disk_isr()
     if (disk.info[id].status != 0)
       panic("virtio_disk_intr status");
 
-    struct buf *b = disk.info[id].b;
+    struct blk *b = disk.info[id].b;
-    b->disk = 0; // disk is done with buf
 
     disk.used_idx += 1;
   }

08-BlockDeviceDriver/virtio.h

@@ -59,7 +59,7 @@ typedef struct virtq_desc
    * flags: 用於控制 descriptor 。
    * next: 告訴 Device 下一個描述符的 Index 。如果指定了 VIRTQ_DESC_F_NEXT， Device 僅讀取該字段。否則無效。
    */
-  uint64 addr;
+  uint32 addr;
   uint32 len;
   uint16 flags;
   uint16 next;
@@ -115,5 +115,5 @@ typedef struct virtio_blk_req
 {
   uint32 type;     // VIRTIO_BLK_T_IN or ..._OUT
   uint32 reserved; // 將 Header 擴充到 16-byte ，並將 64-bit sector 移到正確的位置。
-  uint64 sector;
+  uint32 sector;
 } virtio_blk_req_t;

README.md

@@ -62,3 +62,4 @@ in the `LICENSE` file.
 - [Adventures in RISC-V](https://matrix89.github.io/writes/writes/experiments-in-riscv/)
 - [Xv6, a simple Unix-like teaching operating system](https://pdos.csail.mit.edu/6.828/2020/xv6.html)
 - [Basics of programming a UART](https://www.activexperts.com/serial-port-component/tutorials/uart/)
+- [QEMU RISC-V Virt Machine Platform](https://github.com/riscv/opensbi/blob/master/docs/platform/qemu_virt.md)

doc/tw/08-BlockDeviceDriver.md

@@ -108,7 +108,7 @@ struct virtq_used
 +------------------+
 ```
 
-完成 Device Driver 方便我們在日後實現檔案系統。
+完成 Device Driver 會讓我們在日後實現檔案系統更為方便，此外，參考 xv6-riscv 的設計，我們還會需要實現一層 Buffer cache 用來同步硬碟上的資料。
 
 ### 指定寫入的 Sector
 
@@ -153,7 +153,7 @@ if(write)
   buf0->type = VIRTIO_BLK_T_OUT; // write the disk
 else
   buf0->type = VIRTIO_BLK_T_IN; // read the disk
-buf0->reserved = 0; // The reserved portion is used to pad the header to 16 bytes and move the 64-bit sector field to the correct place.
+buf0->reserved = 0; // The reserved portion is used to pad the header to 16 bytes and move the 32-bit sector field to the correct place.
 buf0->sector = sector; // specify the sector that we wanna modified.
 ```