Linux驱动分析之MMC子系统框架

//描述控制器structmmc_host {
structdevice*parent;
structdeviceclass_dev;
intindex;
conststructmmc_host_ops*ops; //host操作函数structmmc_pwrseq*pwrseq;
unsignedintf_min;
unsignedintf_max;
unsignedintf_init;
u32ocr_avail;
u32ocr_avail_sdio;  //SDIO OCR寄存器u32ocr_avail_sd;  //SD OCR寄存器u32ocr_avail_mmc;  //MMC OCR寄存器structwakeup_source*ws;  /* Enable consume of uevents */u32max_current_330;
u32max_current_300;
u32max_current_180;
u32caps;    //host特性u32caps2;    //更多host特性intfixed_drv_type;  //固定驱动类型, 不可移除的设备使用mmc_pm_flag_tpm_caps;  //PM特性//host块数据unsignedintmax_seg_size;  /* see blk_queue_max_segment_size */unsignedshortmax_segs;  /* see blk_queue_max_segments */unsignedshortunused;
unsignedintmax_req_size;  //单个请求的最大字节数unsignedintmax_blk_size;  //单个mmc块最大大小unsignedintmax_blk_count;  //单个请求中最大块数unsignedintmax_busy_timeout; //最大繁忙超时时间 ms//私有数据spinlock_tlock;    //总线操作时的锁structmmc_iosios;    //当前IO总线设置unsignedintuse_spi_crc:1;
unsignedintclaimed:1;  //host声明unsignedintdoing_init_tune:1; //表示初始化调节中，调节指调节采样点unsignedintcan_retune:1;  //表示是否可重新调节unsignedintdoing_retune:1;  //表示重新调节中unsignedintretune_now:1;  //表示下一个请求中重新调节unsignedintretune_paused:1; //表示重新调节暂时关闭unsignedintretune_crc_disable:1; /* don't trigger retune upon crc */unsignedintcan_dma_map_merge:1; /* merging can be used */intrescan_disable;  //关闭卡检测intrescan_entered;  //用于不可移除的设备intneed_retune;  //表示是否需要重新调节inthold_retune;  //表示推迟重新调整unsignedintretune_period;  //重新调整的周期structtimer_listretune_timer;  //重新调整的Timerbooltrigger_card_event; /* card_event necessary */structmmc_card*card;    //附着在host上的设备wait_queue_head_twq;             //等待队列structmmc_ctx*claimer;  //host上下文intclaim_cnt;  /* "claim" nesting count */structmmc_ctxdefault_ctx;  //默认上下文structdelayed_workdetect;
intdetect_change;  //卡检测标志structmmc_slotslot;
conststructmmc_bus_ops*bus_ops;  //总线操作函数集unsignedintsdio_irqs;      //sdio中断structtask_struct*sdio_irq_thread; //中断处理线程structdelayed_worksdio_irq_work;
boolsdio_irq_pending;
atomic_tsdio_irq_thread_abort;
mmc_pm_flag_tpm_flags;  /* requested pm features */structled_trigger*led;    /* activity led */#ifdef CONFIG_REGULATORboolregulator_enabled; /* regulator state */#endifstructmmc_supplysupply;
structdentry*debugfs_root;
//数据传输过程中进行命令传输structmmc_request*ongoing_mrq; 
#ifdef CONFIG_FAIL_MMC_REQUESTstructfault_attrfail_mmc_request;
#endifunsignedintactual_clock;  /* Actual HC clock rate */unsignedintslotno;  /* used for sdio acpi binding */intdsr_req;  /* DSR value is valid */u32dsr;  /* optional driver stage (DSR) value *///命令队列引擎conststructmmc_cqe_ops*cqe_ops;
void*cqe_private;
intcqe_qdepth;
boolcqe_enabled;
boolcqe_on;
/* Inline encryption support */#ifdef CONFIG_MMC_CRYPTOstructblk_keyslot_managerksm;
#endif/* Host Software Queue support */boolhsq_enabled;
unsignedlongprivate[] ____cacheline_aligned;
};

//描述卡structmmc_card {
structmmc_host*host;    //设备所属的hoststructdevicedev;    /* the device */u32ocr;    //当前OCR设置unsignedintrca;    //设备的卡地址unsignedinttype;    //卡类型unsignedintstate;    //卡状态unsignedintquirks;   /* card quirks */unsignedintquirk_max_rate;  /* max rate set by quirks */boolreenable_cmdq;  //重新使能命令队列unsignedinterase_size;  //扇区擦除的大小unsignedinterase_shift;  /* if erase unit is power 2 */unsignedintpref_erase;  /* in sectors */unsignedinteg_boundary;  /* don't cross erase-group boundaries */unsignedinterase_arg;  /* erase / trim / discard */u8erased_byte;  //已经擦除的字节数u32raw_cid[4];  //原始卡CIDu32raw_csd[4];  //原始卡CSDu32raw_scr[2];  //原始卡SCRu32raw_ssr[16];  //原始卡SSRstructmmc_cidcid;    //原始卡IDstructmmc_csdcsd;    /* card specific */structmmc_ext_csdext_csd;  /* mmc v4 extended card specific */structsd_scrscr;    //附加SD信息structsd_ssrssr;    /* yet more SD information */structsd_switch_capssw_caps;  /* switch (CMD6) caps */structsd_ext_regext_power;  /* SD extension reg for PM */structsd_ext_regext_perf;  /* SD extension reg for PERF */unsignedintsdio_funcs;  //SDIO function数量atomic_tsdio_funcs_probed; /* number of probed SDIO funcs */structsdio_cccrcccr;    //通用卡信息structsdio_ciscis;    //通用tuple信息, tuple指存储结构structsdio_func*sdio_func[SDIO_MAX_FUNCS]; /* SDIO functions (devices) */structsdio_func*sdio_single_irq; /* SDIO function when only one IRQ active */u8major_rev;  //主版本号u8minor_rev;  //次版本号unsignednum_info;  //信息字符串数量constchar**info;    //信息字符串structsdio_func_tuple*tuples;  //未知通用tuplesunsignedintsd_bus_speed;  //总线速率模式设置unsignedintmmc_avail_type;  //支持的设备类型:host或cardunsignedintdrive_strength;  /* for UHS-I, HS200 or HS400 */structdentry*debugfs_root;
structmmc_partpart[MMC_NUM_PHY_PARTITION]; //物理分区unsignedintnr_parts;
structworkqueue_struct*complete_wq;  //私有工作队列};

structmmc_host_ops {
//pre_req和post_req是为双buffervoid  (*post_req)(structmmc_host*host, structmmc_request*req,
interr);
void  (*pre_req)(structmmc_host*host, structmmc_request*req);
void  (*request)(structmmc_host*host, structmmc_request*req);
//提交请求(有原子上下文)int  (*request_atomic)(structmmc_host*host,
structmmc_request*req);
//避免经常调用下面三个函数//IO总线设置void  (*set_ios)(structmmc_host*host, structmmc_ios*ios);
//获取卡是否是只读(0:读写 1:只读)int  (*get_ro)(structmmc_host*host);
//获取卡是否存在int  (*get_cd)(structmmc_host*host);
//使能中断void  (*enable_sdio_irq)(structmmc_host*host, intenable);
/* Mandatory callback when using MMC_CAP2_SDIO_IRQ_NOTHREAD. */void  (*ack_sdio_irq)(structmmc_host*host);
/* optional callback for HC quirks */void  (*init_card)(structmmc_host*host, structmmc_card*card);
int  (*start_signal_voltage_switch)(structmmc_host*host, structmmc_ios*ios);
//检查卡的data[0]是否处于拉低中         int  (*card_busy)(structmmc_host*host);
//SD和eMMC卡的调节命令(tuning command)opcode是不同的int  (*execute_tuning)(structmmc_host*host, u32opcode);
/* Prepare HS400 target operating frequency depending host driver */int  (*prepare_hs400_tuning)(structmmc_host*host, structmmc_ios*ios);
/* Prepare switch to DDR during the HS400 init sequence */int  (*hs400_prepare_ddr)(structmmc_host*host);
/* Prepare for switching from HS400 to HS200 */void  (*hs400_downgrade)(structmmc_host*host);
/* Complete selection of HS400 */void  (*hs400_complete)(structmmc_host*host);
/* Prepare enhanced strobe depending host driver */void  (*hs400_enhanced_strobe)(structmmc_host*host,
structmmc_ios*ios);
int  (*select_drive_strength)(structmmc_card*card,
unsignedintmax_dtr, inthost_drv,
intcard_drv, int*drv_type);
//通过RST_n重置eMMCvoid  (*hw_reset)(structmmc_host*host);
void  (*card_event)(structmmc_host*host);
//多I/O控制器硬件错误回调int  (*multi_io_quirk)(structmmc_card*card,
unsignedintdirection, intblk_size);
//初始化SD express卡int  (*init_sd_express)(structmmc_host*host, structmmc_ios*ios);
};

//描述SDIO功能structsdio_func {
structmmc_card*card;    //所属的卡structdevicedev;    /* the device */sdio_irq_handler_t*irq_handler;  //中断回调unsignedintnum;    //function号 unsignedcharclass;    //标准接口类(class)unsignedshortvendor;    //VID, 厂家IDunsignedshortdevice;    //DID, 设备IDunsignedmax_blksize;  //最大块大小unsignedcur_blksize;  //当前块大小unsignedenable_timeout;  //最大使能超时时间unsignedintstate;    //function状态u8*tmpbuf;  //DMA:临时bufferu8major_rev;  //主版本号u8minor_rev;  //次版本号unsignednum_info;  //信息字符串数量constchar**info;    //信息字符串structsdio_func_tuple*tuples;         //CIS tuple};

//mmc卡驱动，和platform_driver类似structmmc_driver {
structdevice_driverdrv;
int (*probe)(structmmc_card*card);
void (*remove)(structmmc_card*card);
void (*shutdown)(structmmc_card*card);
};

//表示一个传输请求structmmc_request {
structmmc_command*sbc;     //多块传输时设置块数，即CMD23命令structmmc_command*cmd;     //请求的命令structmmc_data*data;    //本次请求所携带的数据structmmc_command*stop;    //停止命令//完成量，用于同步命令完成structcompletioncompletion;
structcompletioncmd_completion;
void            (*done)(structmmc_request*); //命令完成回调void            (*recovery_notifier)(structmmc_request*);
structmmc_host*host; //host对象boolcap_cmd_during_tfr; //数据传输过程或忙等待时是否允许其他命令inttag;
#ifdef CONFIG_MMC_CRYPTOconststructbio_crypt_ctx*crypto_ctx;
intcrypto_key_slot;
#endif};

//表示commandstructmmc_command {
u32opcode; //命令码，比如CMD5, opcode=5u32arg;    //参数u32resp[4]; //应答unsignedintflags;      /* expected response type */unsignedintretries;    //最大重试次数interror;      //错误码unsignedintbusy_timeout;   //繁忙超时时间structmmc_data*data;      //命令关联的数据structmmc_request*mrq;       //关联的mmc_request};

//表示数据structmmc_data {
unsignedinttimeout_ns; //数据超时时间，最大80msunsignedinttimeout_clks;  //数据超时(时钟)unsignedintblksz;     //数据块大小unsignedintblocks;    //块数量unsignedintblk_addr;  //块地址interror;      /* data error */unsignedintflags;
unsignedintbytes_xfered;
structmmc_command*stop;      //停止命令structmmc_request*mrq;       //关联的mmc_requestunsignedintsg_len;     /* size of scatter list */intsg_count;   /* mapped sg entries */structscatterlist*sg;        /* I/O scatter list */s32host_cookie;    //host私有数据};

//注册/注销mmc驱动intmmc_register_driver(structmmc_driver*drv)
voidmmc_unregister_driver(structmmc_driver*drv)
/*******************************************************///分配host结构体structmmc_host*mmc_alloc_host(intextra, structdevice*dev)
//注册host到驱动模型intmmc_add_host(structmmc_host*host)
//从驱动模型中移除hostvoidmmc_remove_host(structmmc_host*host)
//释放host结构体voidmmc_free_host(structmmc_host*host)
/*******************************************************///分配sdio_func结构体structsdio_func*sdio_alloc_func(structmmc_card*card)
//注册function到驱动模型intsdio_add_func(structsdio_func*func)
/*******************************************************///分配mmc_card结构体structmmc_card*mmc_alloc_card(structmmc_host*host, structdevice_type*type)
//注册卡到驱动模型intmmc_add_card(structmmc_card*card)
//发送传输请求，mmc_start_request函数最终调用host->ops->requestintmmc_start_request(structmmc_host*host, structmmc_request*mrq)