linux中probe函数传递参数的寻找（下）

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linux中probe函数传递参数的寻找（下）         通过追寻driver的脚步，我们有了努力的方向：只有找到spi_bus_type的填充device即可，下面该从device去打通，当两个连通之日，也是任督二脉打通之时。先从设备定义去查看，在mach-smdk6410.c中定义了硬件设备信息，从这作为突破口。/* for mx25lx*/static void cs_set_level(unsigned line_id, int lvl) {   gpio_direction_output(line_id, lvl);};static struct s3c64xx_spi_csinfos3c64xx_spi1_csinfo = {       .fb_delay=0x3,       .line=S3C64XX_GPC(7),       .set_level=cs_set_level,}; static int mx25lx_ioSetup(struct spi_device*spi){         printk(KERN_INFO"mx25lx: setup gpio pins CS and External Int\n");         s3c_gpio_setpull(S3C64XX_GPL(8),S3C_GPIO_PULL_UP);              //External interrupt from CAN controller         s3c_gpio_cfgpin(S3C64XX_GPL(8),S3C_GPIO_SFN(3));                   //External interrupt from CAN controller (hopefully external interrupt)         //s3c_gpio_cfgpin(S3C64XX_GPL(8),S3C_GPIO_INPUT);                 //External interrupt from CAN controller         s3c_gpio_setpull(S3C64XX_GPC(7),S3C_GPIO_PULL_NONE);       // Manual chipselect pin as used in 6410_set_cs         s3c_gpio_cfgpin(S3C64XX_GPC(7),S3C_GPIO_OUTPUT);                // Manualchip select pin as used in 6410_set_cs         return0;} static struct mx25lx_platform_datamx25lx_info ={         .oscillator_frequency= 8000000,         .board_specific_setup= mx25lx_ioSetup,         .transceiver_enable= NULL,         .power_enable= NULL,}; static struct spi_board_info __initdataforlinx6410_mc251x_info[]  ={         {                   .modalias= "mcp2515",                   .platform_data = &mx25lx_info,                   .irq= IRQ_EINT(16),                   .max_speed_hz= 10*1000*1000,                    .bus_num= 1,                   .chip_select= 0,                   .mode= SPI_MODE_0,                      .controller_data=&s3c64xx_spi1_csinfo,         },}; struct platform_device s3c64xx_device_spi0= {         .name                 = "s3c64xx-spi",         .id               = 0,         .num_resources         =ARRAY_SIZE(s3c64xx_spi0_resource),         .resource   =s3c64xx_spi0_resource,         .dev= {                   .dma_mask               = &spi_dmamask,                   .coherent_dma_mask     = DMA_BIT_MASK(32),                   .platform_data= &s3c64xx_spi0_pdata,         },}; static struct platform_device*smdk6410_devices[] __initdata ={         ……         /*addby fatfish*/         &s3c64xx_device_spi0,         &s3c64xx_device_spi1,};          其中platform_device定义为：struct platform_device {         constchar        * name;         int              id;         structdevice    dev;         u32            num_resources;         structresource        * resource;          conststruct platform_device_id     *id_entry;          /*MFD cell pointer */         structmfd_cell *mfd_cell;          /*arch specific additions */         structpdev_archdata      archdata;};          初始化函数如下：static void __initsmdk6410_machine_init(void){         ……         s3c64xx_spi_set_info(0,0,1);         s3c64xx_spi_set_info(1,0,1);         spi_register_board_info(forlinx6410_mc251x_info,ARRAY_SIZE(forlinx6410_mc251x_info));         ……}       其中的注册板信息的函数如下，后项参数为1，其中board_list为spi.c中定义的全局变量，即：static LIST_HEAD(board_list);。int __initspi_register_board_info(structspi_board_info const *info, unsigned n){         structboardinfo *bi;         inti;          bi= kzalloc(n * sizeof(*bi), GFP_KERNEL);         if(!bi)                   return-ENOMEM;          for(i = 0; i < n; i++, bi++, info++) {                   structspi_master *master;                    memcpy(&bi->board_info,info, sizeof(*info));                   mutex_lock(&board_lock);                   list_add_tail(&bi->list,&board_list);                   list_for_each_entry(master,&spi_master_list, list)                            spi_match_master_to_boardinfo(master,&bi->board_info);                   mutex_unlock(&board_lock);         }          return0;}         其中结果成员如下：


         先加锁，然后将board_list加入链接中，在遍历设备，最关键的函数是：static voidspi_match_master_to_boardinfo(struct spi_master *master,                                     structspi_board_info *bi){         structspi_device *dev;          if(master->bus_num != bi->bus_num)                   return;          dev= spi_new_device(master, bi);         if(!dev)                   dev_err(master->dev.parent,"can't create new device for %s\n",                            bi->modalias);}         spi_new_device作用是实例化一个新设备，定义如下：struct spi_device *spi_new_device(structspi_master *master,                                       struct spi_board_info *chip){         structspi_device     *proxy;         int                       status;           proxy= spi_alloc_device(master);         if(!proxy)                   returnNULL; ……         strlcpy(proxy->modalias,chip->modalias, sizeof(proxy->modalias));         proxy->dev.platform_data = (void *)chip->platform_data;         proxy->controller_data= chip->controller_data;         proxy->controller_state= NULL;          status= spi_add_device(proxy);         if(status < 0) {                   spi_dev_put(proxy);                   returnNULL;         }          returnproxy;}          拷贝了platform_data，即mx25lx_info。其中的spi_alloc_device函数定义如下：struct spi_device *spi_alloc_device(structspi_master *master){         structspi_device     *spi;         structdevice             *dev =master->dev.parent;          if(!spi_master_get(master))                   returnNULL;          spi= kzalloc(sizeof *spi, GFP_KERNEL);         if(!spi) {                   dev_err(dev,"cannot alloc spi_device\n");                   spi_master_put(master);                   returnNULL;         }          spi->master= master;         spi->dev.parent= dev;         spi->dev.bus= &spi_bus_type;         spi->dev.release= spidev_release;         device_initialize(&spi->dev);         returnspi;}         在这个定义中将spi_bus_type和dev联系起来，不过此时还没有我们定义的设备信息，设备信息在接下来的赋值中完成。         最后是spi_add_device，将设备信息提交。int spi_add_device(struct spi_device *spi){         staticDEFINE_MUTEX(spi_add_lock);         structdevice *dev = spi->master->dev.parent;         structdevice *d;         intstatus; ……         mutex_lock(&spi_add_lock);          d= bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));         ……         status= spi_setup(spi);         if(status < 0) {                   dev_err(dev,"can't setup %s, status %d\n",                                     dev_name(&spi->dev),status);                   gotodone;         }……done:         mutex_unlock(&spi_add_lock);         returnstatus;}         最终完成将spi_bus_type与定义的device信息联系起来。由于本人才疏学浅，不正确的地方，恳求大牛指正，在此表示感谢