JJJ - linux reset framework

基于 “arch/arm/mach-imx/src.c”
参考这篇

reset-framework涉及的文件：
include/linux/reset-controller.h
drivers/reset/core.c

总之感觉就是封装了一个设备的复位操作，并可以通过设备树去灵活配置复位操作

静态定义:

static struct reset_controller_dev imx_reset_controller = {.ops = &imx_src_ops,.nr_resets = ARRAY_SIZE(sw_reset_bits),
};static const int sw_reset_bits[5] = {BP_SRC_SCR_SW_GPU_RST,BP_SRC_SCR_SW_VPU_RST,BP_SRC_SCR_SW_IPU1_RST,BP_SRC_SCR_SW_OPEN_VG_RST,BP_SRC_SCR_SW_IPU2_RST
};

关于ARRAY_SIZE这个宏，参考这篇blog

结构体类型定义

struct reset_controller_dev 类型

/*** struct reset_controller_dev - reset controller entity that might*                               provide multiple reset controls* @ops: a pointer to device specific struct reset_control_ops* @owner: kernel module of the reset controller driver* @list: internal list of reset controller devices* @of_node: corresponding device tree node as phandle target* @of_reset_n_cells: number of cells in reset line specifiers* @of_xlate: translation function to translate from specifier as found in the*            device tree to id as given to the reset control ops* @nr_resets: number of reset controls in this reset controller device*/
struct reset_controller_dev {struct reset_control_ops *ops;struct module *owner;struct list_head list;struct device_node *of_node;int of_reset_n_cells;int (*of_xlate)(struct reset_controller_dev *rcdev,const struct of_phandle_args *reset_spec);unsigned int nr_resets;
};

struct reset_control定义：

/*** struct reset_control - a reset control* @rcdev: a pointer to the reset controller device*         this reset control belongs to* @id: ID of the reset controller in the reset*      controller device*/
struct reset_control {struct reset_controller_dev *rcdev;struct device *dev;unsigned int id;
};

struct reset_control_ops定义

/*** struct reset_control_ops** @reset: for self-deasserting resets, does all necessary*         things to reset the device* @assert: manually assert the reset line, if supported* @deassert: manually deassert the reset line, if supported* @status: return the status of the reset line, if supported*/
struct reset_control_ops {int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
};

在函数 imx_src_init中

struct device_node *np;np = of_find_compatible_node(NULL, NULL, "fsl,imx51-src");
...
imx_reset_controller.of_node = np;if (IS_ENABLED(CONFIG_RESET_CONTROLLER))reset_controller_register(&imx_reset_controller);
...

np对应的结点为：

            src: src@020d8000 {compatible = "fsl,imx6ul-src", "fsl,imx51-src";reg = <0x020d8000 0x4000>;interrupts = <GIC_SPI 91 IRQ_TYPE_LEVEL_HIGH>,<GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>;#reset-cells = <1>;};

看reset_controller_register

/*** reset_controller_register - register a reset controller device* @rcdev: a pointer to the initialized reset controller device*/
int reset_controller_register(struct reset_controller_dev *rcdev)
{if (!rcdev->of_xlate) {rcdev->of_reset_n_cells = 1;rcdev->of_xlate = of_reset_simple_xlate;}mutex_lock(&reset_controller_list_mutex);list_add(&rcdev->list, &reset_controller_list);mutex_unlock(&reset_controller_list_mutex);return 0;
}
EXPORT_SYMBOL_GPL(reset_controller_register);