text: #ifndef LINUX_MMC_IOCTL_H
  #define LINUX_MMC_IOCTL_H
  
  #include <linux/types.h>
  
  struct mmc_ioc_cmd {
  	/* Implies direction of data.  true = write, false = read */
  	int write_flag;
  
  	/* Application-specific command.  true = precede with CMD55 */
  	int is_acmd;
  
  	__u32 opcode;
  	__u32 arg;
  	__u32 response[4];  /* CMD response */
  	unsigned int flags;
  	unsigned int blksz;
  	unsigned int blocks;
  
  	/*
  	 * Sleep at least postsleep_min_us useconds, and at most
  	 * postsleep_max_us useconds *after* issuing command.  Needed for
  	 * some read commands for which cards have no other way of indicating
  	 * they're ready for the next command (i.e. there is no equivalent of
  	 * a "busy" indicator for read operations).
  	 */
  	unsigned int postsleep_min_us;
  	unsigned int postsleep_max_us;
  
  	/*
  	 * Override driver-computed timeouts.  Note the difference in units!
  	 */
  	unsigned int data_timeout_ns;
  	unsigned int cmd_timeout_ms;
  
  	/*
  	 * For 64-bit machines, the next member, ``__u64 data_ptr``, wants to
  	 * be 8-byte aligned.  Make sure this struct is the same size when
  	 * built for 32-bit.
  	 */
  	__u32 __pad;
  
  	/* DAT buffer */
  	__u64 data_ptr;
  };
  #define mmc_ioc_cmd_set_data(ic, ptr) ic.data_ptr = (__u64)(unsigned long) ptr
  
  /**
   * combo command used ioctl cmd id MMC_COMBO_IOC_CMD
   */
  struct mmc_combo_cmd_info {
  	uint8_t  num_of_combo_cmds;
  	struct mmc_ioc_cmd *mmc_ioc_cmd_list;
  };
  
  #define MMC_IOC_CMD _IOWR(MMC_BLOCK_MAJOR, 0, struct mmc_ioc_cmd)
  /*
   * MMC_COMBO_IOC_CMD: This is used to send a array of eMMC commands.
   * each entry in struct mmc_ioc_cmd will have details of
   * one eMMC command.
   * The mmc driver will issue all commands in array in sequence to card.
   * To ensure atomic operations of all commands in array,
   * a single lock is acquired.
   */
  #define MMC_COMBO_IOC_CMD _IOWR(MMC_BLOCK_MAJOR, 1, struct mmc_combo_cmd_info)
  /*
   * Since this ioctl is only meant to enhance (and not replace) normal access
   * to the mmc bus device, an upper data transfer limit of MMC_IOC_MAX_BYTES
   * is enforced per ioctl call.  For larger data transfers, use the normal
   * block device operations.
   */
  #define MMC_IOC_MAX_BYTES  (512L * 256)
  #endif /* LINUX_MMC_IOCTL_H */
  