Interrupt mask

Interrupt mask是指用于屏蔽中断的控制寄存器或者标志位。在嵌入式系统中，中断是一种常见的处理器外部事件处理方式。当中断事件发生时，处理器会立即中断正在执行的程序，并跳转到中断服务程序来处理该事件。但是，在某些情况下，我们希望暂时屏蔽中断，以防止中断事件干扰正在执行的程序。这时，就可以使用Interrupt mask来屏蔽中断。通常，Interrupt mask由一个或多个控制寄存器或者标志位组成，它们的状态决定了哪些中断是被屏蔽的，哪些中断是允许的。通过设置和清除这些控制寄存器或者标志位，可以灵活地控制中断的开关。

相关问题

文件系统的void SysTick_Handler(void) { g_timeMilliseconds++; } 和freertos里port.c的void xPortSysTickHandler( void ) { /* The SysTick runs at the lowest interrupt priority, so when this interrupt executes all interrupts must be unmasked. There is therefore no need to save and then restore the interrupt mask value as its value is already known - therefore the slightly faster vPortRaiseBASEPRI() function is used in place of portSET_INTERRUPT_MASK_FROM_ISR(). / //g_timeMilliseconds++; vPortRaiseBASEPRI(); { / Increment the RTOS tick. / if( xTaskIncrementTick() != pdFALSE ) { / A context switch is required. Context switching is performed in the PendSV interrupt. Pend the PendSV interrupt. */ portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT; } } vPortClearBASEPRIFromISR(); }重复定义了怎么解决，给我具体的解决方法带代码

如果您遇到了重复定义的问题，可以使用如下方法解决：

1. 将 `g_timeMilliseconds` 定义为一个全局变量，然后在两个函数中都使用它，而不是在 `SysTick_Handler` 函数中直接对它进行操作。

例如，您可以在某个头文件中定义 `g_timeMilliseconds`：

// 在头文件中定义全局变量
extern uint32_t g_timeMilliseconds;

然后在一个 C 文件中定义这个全局变量：

#include "header.h"

uint32_t g_timeMilliseconds = 0;

然后在 `SysTick_Handler` 函数中，将其修改为：

void SysTick_Handler(void) {
    g_timeMilliseconds++;
}

在 `xPortSysTickHandler` 函数中，您可以通过 `g_timeMilliseconds` 全局变量来获取当前时间的值，而不需要在该函数中对其进行操作。例如：

void xPortSysTickHandler( void ) {
    /* Increment the RTOS tick. */
    if( xTaskIncrementTick() != pdFALSE ) {
        /* A context switch is required. Context switching is performed in the PendSV interrupt. Pend the PendSV interrupt. */
        portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
    }
}

2. 如果您仍然想要在 `xPortSysTickHandler` 函数中对时间进行操作，您可以将其代码合并到 `SysTick_Handler` 函数中，而不需要在 `xPortSysTickHandler` 函数中重新定义。例如：

void SysTick_Handler(void) {
    g_timeMilliseconds++;

    /* Increment the RTOS tick. */
    if( xTaskIncrementTick() != pdFALSE ) {
        /* A context switch is required. Context switching is performed in the PendSV interrupt. Pend the PendSV interrupt. */
        portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
    }
}

然后在 `xPortSysTickHandler` 函数中，您可以删除对 `g_timeMilliseconds` 的操作，只保留对 RTOS tick 的操作：

void xPortSysTickHandler( void ) {
    /* Increment the RTOS tick. */
    if( xTaskIncrementTick() != pdFALSE ) {
        /* A context switch is required. Context switching is performed in the PendSV interrupt. Pend the PendSV interrupt. */
        portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
    }
}

struct ring_buffer { int head; int tail; struct msg *data; int size; unsigned int capacity; }; struct msg { u16 module_id; u16 cmd_id; u16 cmd_subid; u16 complete; u8 data[128]; };struct pokemon_uart_port { struct uart_port port; struct clk *clk; const struct vendor_data vendor; unsigned int im; / interrupt mask / unsigned int old_status; unsigned int fifosize; unsigned int old_cr; / state during shutdown */ unsigned int fixed_baud; struct ring_buffer tx_buf; struct ring_buffer rx_buf; char type[12]; };struct ring_buffer ring_buffer_init(unsigned int capacity) { struct ring_buffer rbuf=kmalloc(sizeof(struct ring_buffer),GFP_KERNEL); rbuf->capacity=capacity; rbuf->head = rbuf->size=0; rbuf->tail = capacity - 1; rbuf->data = kmalloc(rbuf->capacity * sizeof(struct msg), GFP_KERNEL); printk(KERN_DEBUG "ring_buffer create successfully!/n"); return rbuf; }static int pokemon_uart_probe(struct amba_device *dev, const struct amba_id *id) { struct pokemon_uart_port *pup; struct vendor_data *vendor = id->data; int portnr, ret; portnr = pokemon_find_free_port(); if (portnr < 0) return portnr; pup = devm_kzalloc(&dev->dev, sizeof(struct pokemon_uart_port), GFP_KERNEL); if(!pup) return -ENOMEM; pup->clk = devm_clk_get(&dev->dev, NULL); if(IS_ERR(pup->clk)) return PTR_ERR(pup->clk); pup->port.irq = dev->irq[0]; pup->port.line = portnr; pup->vendor = vendor; pup->fifosize = 32; pup->port.iotype = pup->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; pup->port.ops = &pokemon_uart_ops; snprintf(pup->type, sizeof(pup->type), "PL011 rev%u", amba_rev(dev)); pup->tx_buf = ring_buffer_init(10); pup->rx_buf = ring_buffer_init(10); ret = pokemon_setup_port(&dev->dev, pup, &dev->res, portnr); if (ret) return ret; amba_set_drvdata(dev, pup); return pokemon_register_port(pup); }检查一下这段linux内核驱动代码中，有无代码逻辑和格式错误，如果有，请给出修改之后的代码

以下是修改后的代码：

struct ring_buffer {
    int head;
    int tail;
    struct msg *data;
    int size;
    unsigned int capacity;
};

struct msg {
    u16 module_id;
    u16 cmd_id;
    u16 cmd_subid;
    u16 complete;
    u8 data[128];
};

struct pokemon_uart_port {
    struct uart_port port;
    struct clk *clk;
    const struct vendor_data vendor;
    unsigned int im; /* interrupt mask */
    unsigned int old_status;
    unsigned int fifosize;
    unsigned int old_cr; /* state during shutdown */
    unsigned int fixed_baud;
    struct ring_buffer tx_buf;
    struct ring_buffer rx_buf;
    char type[12];
};

struct ring_buffer *ring_buffer_init(unsigned int capacity) {
    struct ring_buffer *rbuf = kmalloc(sizeof(struct ring_buffer), GFP_KERNEL);
    if (!rbuf) {
        return NULL;
    }
    rbuf->capacity = capacity;
    rbuf->head = rbuf->size = 0;
    rbuf->tail = capacity - 1;
    rbuf->data = kmalloc(rbuf->capacity * sizeof(struct msg), GFP_KERNEL);
    if (!rbuf->data) {
        kfree(rbuf);
        return NULL;
    }
    printk(KERN_DEBUG "ring_buffer create successfully!\n");
    return rbuf;
}

static int pokemon_uart_probe(struct amba_device *dev, const struct amba_id *id) {
    struct pokemon_uart_port *pup;
    struct vendor_data *vendor = id->data;
    int portnr, ret;

    portnr = pokemon_find_free_port();
    if (portnr < 0) {
        return portnr;
    }

    pup = devm_kzalloc(&dev->dev, sizeof(struct pokemon_uart_port), GFP_KERNEL);
    if (!pup) {
        return -ENOMEM;
    }

    pup->clk = devm_clk_get(&dev->dev, NULL);
    if (IS_ERR(pup->clk)) {
        return PTR_ERR(pup->clk);
    }

    pup->port.irq = dev->irq[0];
    pup->port.line = portnr;
    pup->vendor = vendor;
    pup->fifosize = 32;
    pup->port.iotype = pup->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
    pup->port.ops = &pokemon_uart_ops;
    snprintf(pup->type, sizeof(pup->type), "PL011 rev%u", amba_rev(dev));
    pup->tx_buf.data = NULL;
    pup->rx_buf.data = NULL;
    pup->tx_buf.capacity = 10;
    pup->rx_buf.capacity = 10;
    pup->tx_buf.size = 0;
    pup->rx_buf.size = 0;
    pup->tx_buf.head = 0;
    pup->tx_buf.tail = pup->tx_buf.capacity - 1;
    pup->rx_buf.head = 0;
    pup->rx_buf.tail = pup->rx_buf.capacity - 1;
    pup->tx_buf.data = kmalloc(pup->tx_buf.capacity * sizeof(struct msg), GFP_KERNEL);
    if (!pup->tx_buf.data) {
        devm_kfree(&dev->dev, pup);
        return -ENOMEM;
    }
    pup->rx_buf.data = kmalloc(pup->rx_buf.capacity * sizeof(struct msg), GFP_KERNEL);
    if (!pup->rx_buf.data) {
        kfree(pup->tx_buf.data);
        devm_kfree(&dev->dev, pup);
        return -ENOMEM;
    }

    ret = pokemon_setup_port(&dev->dev, pup, &dev->res, portnr);
    if (ret) {
        kfree(pup->tx_buf.data);
        kfree(pup->rx_buf.data);
        devm_kfree(&dev->dev, pup);
        return ret;
    }

    amba_set_drvdata(dev, pup);

    ret = pokemon_register_port(pup);
    if (ret) {
        kfree(pup->tx_buf.data);
        kfree(pup->rx_buf.data);
        devm_kfree(&dev->dev, pup);
        return ret;
    }

    return 0;
}

修改说明：

1. `ring_buffer_init` 函数返回类型应该是 `struct ring_buffer *` 而不是 `struct ring_buffer`。
2. `ring_buffer_init` 函数内存分配失败时需要释放已经分配的内存。
3. `pup->tx_buf` 和 `pup->rx_buf` 的 `data` 成员在初始化之前需要置为 `NULL`。
4. `pup->tx_buf` 和 `pup->rx_buf` 的 `size` 成员在初始化之前需要置为 `0`。
5. `pup->tx_buf` 和 `pup->rx_buf` 的 `head` 和 `tail` 成员在初始化时需要分别设置为 `0` 和 `capacity - 1`。
6. 在 `pokemon_uart_probe` 函数中，`pup->tx_buf` 和 `pup->rx_buf` 的 `data` 成员需要进行内存分配，并在分配失败时要释放已经分配的内存。
7. 在 `pokemon_uart_probe` 函数中，需要在成功分配内存后初始化 `pup->tx_buf` 和 `pup->rx_buf` 的 `capacity` 成员。