sd_disk.c

#include "types.h"
#include "riscv.h"
#include "defs.h"
#include "param.h"
#include "spinlock.h"
#include "sleeplock.h"
#include "fs.h"
#include "buf.h"
#include "sdcard.h"

struct sd_disk {
  int initialized;
  struct spinlock lock;
} sddisk;

void sd_disk_init(void)
{
  // Initialize lock.
  initlock(&sddisk.lock, "sd_disk");

  if(sd_init(1, VF2_SD_CS, VF2_SD_MISO, VF2_SD_CLK, VF2_SD_MOSI) != 0) {
    sd_deinit();
    panic("sd_disk: sd_init failed");
  }
  sddisk.initialized = 1;
}

//
// sd_disk_rw: Perform a read or write operation using the SD card.
//
// b: pointer to the buffer structure (including b->blockno and b->data),
// write: nonzero for write, 0 for read.
//
// Since the SD card operates on 512-byte blocks, we need to read/write
// two blocks for each buffer operation.
void sd_disk_rw(struct buf *b, int write)
{
  uint32 blockno = b->blockno;
  int ret;

  acquire(&sddisk.lock);

  if(!sddisk.initialized)
    panic("sd_disk_rw: disk not initialized");

  if(write) {
    for(int i=0; i<BSIZE/SD_BSIZE; i++) {
      ret = sd_write_block(blockno*(BSIZE/SD_BSIZE)+i, b->data+i*SD_BSIZE);
      if(ret != 0) {
        release(&sddisk.lock);
        panic("sd_disk_rw: SD card write operation failed");
      }
    }
  } else {
    for(int i=0; i<BSIZE/SD_BSIZE; i++) {
      ret = sd_read_block(blockno*(BSIZE/SD_BSIZE)+i, b->data+i*SD_BSIZE);
      if(ret != 0) {
        release(&sddisk.lock);
        panic("sd_disk_rw: SD card read operation failed");
      }
    }
  }

  __sync_synchronize();

  // buffer done
  b->disk = 0;
  wakeup(b);

  release(&sddisk.lock);
}