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linux中probe函数传递参数的寻找（下）

發(fā)布時間：2025/4/16 linux 19 豆豆

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linux中probe函數(shù)傳遞參數(shù)的尋找（下）

???????? 通過追尋driver的腳步，我們有了努力的方向：只有找到spi_bus_type的填充device即可，下面該從device去打通，當(dāng)兩個連通之日，也是任督二脈打通之時。先從設(shè)備定義去查看，在mach-smdk6410.c中定義了硬件設(shè)備信息，從這作為突破口。

/* 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定義為：

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;

};

???????? 初始化函數(shù)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));

???????? ……

}

?????? 其中的注冊板信息的函數(shù)如下，后項參數(shù)為1，其中board_list為spi.c中定義的全局變量，即：static LIST_HEAD(board_list);。

int __init

spi_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;

}

???????? 其中結(jié)果成員如下：

???????? 先加鎖，然后將board_list加入鏈接中，在遍歷設(shè)備，最關(guān)鍵的函數(shù)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作用是實例化一個新設(shè)備，定義如下：

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;

}

???????? 拷貝了platform_data，即mx25lx_info。其中的spi_alloc_device函數(shù)定義如下：

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;

}

???????? 在這個定義中將spi_bus_type和dev聯(lián)系起來，不過此時還沒有我們定義的設(shè)備信息，設(shè)備信息在接下來的賦值中完成。

???????? 最后是spi_add_device，將設(shè)備信息提交。

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;

}

???????? 最終完成將spi_bus_type與定義的device信息聯(lián)系起來。由于本人才疏學(xué)淺，不正確的地方，懇求大牛指正，在此表示感謝

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