Documentation/arm/firmware.txt

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以下为正文

Interface for registering and calling firmware-specific operations for ARM.

为ARM接口注册和调用固件的具体操作。

----

Tomasz Figa <t.figa@samsung.com>著

Some boards are running with secure firmware running in TrustZone secure 

world, which changes the way some things have to be initialized. 

有些在TrustZone安全世界的主板在安全运行固件的配置下运行，它改变了有

些程序必须初始化的方法。

This makes a need to provide an interface for such platforms to specify 

available firmware operations and call them when needed.

这使得对指定可用固件操作以及需要时候可以回应的平台提供一个接口有所需。

Firmware operations can be specified using struct firmware_ops

固件操作可以被指定使用struct firmware_ops 

struct firmware_ops {

                   /*

                  * Enters CPU idle mode

                 */

                    int (*do_idle)(void);

                    /*

                    * Sets boot address of specified physical CPU

                    */

                    int (*set_cpu_boot_addr)(int cpu, unsigned long boot_addr);

                    /*

                    * Boots specified physical CPU

                    */

                    int (*cpu_boot)(int cpu);

                    /*

                    * Initializes L2 cache

                    */

                    int (*l2x0_init)(void);

            };

and then registered with register_firmware_ops function

然后注册register_firmware_ops功能

void register_firmware_ops(const struct firmware_ops *ops)

the ops pointer must be non-NULL.

OPS指针必须非空。

There is a default, empty set of operations provided, so there is no need to 

set anything if platform does not require firmware operations.

空集提供操作是默认的，所以如果平台不要求固件操作，也没有必要设置什么。

To call a firmware operation, a helper macro is provided

提供一个帮手宏来调用固件操作

#define call_firmware_op(op, ...)                               \

                    ((firmware_ops->op) ? firmware_ops->op(__VA_ARGS__) : (-ENOSYS))

the macro checks if the operation is provided and calls it or otherwise returns 

-ENOSYS to signal that given operation is not available (for example, to allow fallback 

to legacy operation).

宏检查操作是否提供或以其他方式回馈ENOSYS给出的操作信号不可用（例如，允许退

回到传统的操作）。

Example of registering firmware operations:

登记固件操作的示例：

/* board file */

            static int platformX_do_idle(void)

            {

                    /* tell platformX firmware to enter idle */

                    return 0;

            }

            static int platformX_cpu_boot(int i)

            {

                    /* tell platformX firmware to boot CPU i */

                    return 0;

            }

           static const struct firmware_ops platformX_firmware_ops = {

                    .do_idle        = exynos_do_idle,

                   .cpu_boot       = exynos_cpu_boot,

                    /* other operations not available on platformX */

            };

            /* init_early callback of machine descriptor */

            static void __init board_init_early(void)

            {

                    register_firmware_ops(&platformX_firmware_ops);

            }

Example of using a firmware operation:

使用固件操作的示例：

/* some platform code, e.g. SMP initialization */

            __raw_writel(virt_to_phys(exynos4_secondary_startup),

                    CPU1_BOOT_REG);

            /* Call Exynos specific smc call */

            if (call_firmware_op(cpu_boot, cpu) == -ENOSYS)

                    cpu_boot_legacy(...); /* Try legacy way */

           gic_raise_softirq(cpumask_of(cpu), 1);