中断分配
概述
ESP32-C6 有一个核,28 个外部异步中断。每个中断的优先级别都可独立地通过编程设置。此外,还有 4 个核心本地中断源 (CLINT)。详细信息请参见 ESP32-C6 技术参考手册 [PDF]。
由于中断源数量多于中断,有时多个驱动程序可以共用一个中断。esp_intr_alloc()
抽象隐藏了这些实现细节。
驱动程序可以通过调用 esp_intr_alloc()
,或 esp_intr_alloc_intrstatus()
为某个外设分配中断。通过向此函数传递 flag,可以指定中断类型、优先级和触发方式。然后,中断分配代码会找到适用的中断,使用中断矩阵将其连接到外设,并为其安装给定的中断处理程序和 ISR。
中断分配器提供两种不同的中断类型:共享中断和非共享中断,这两种中断需要不同处理方式。非共享中断在每次调用 esp_intr_alloc()
时,都会分配一个单独的中断,该中断仅用于与其相连的外设,只调用一个 ISR。共享中断则可以由多个外设触发,当其中一个外设发出中断信号时,会调用多个 ISR。因此,针对共享中断的 ISR 应检查对应外设的中断状态,以确定是否需要采取任何操作。
非共享中断可由电平或边缘触发。共享中断只能由电平触发,因为使用边缘触发可能会错过中断。
要解释为什么共享中断只能由电平触发,以外设 A 和外设 B 共用一个边缘触发中断为例进行说明:当外设 B 触发中断时,会将其中断信号设置为高电平,产生一个从低到高的边缘,进而锁存 CPU 中断位,并触发 ISR。接着,ISR 开始执行,检查到此时外设 A 没有触发中断,于是继续处理外设 B 的中断信号,最后将外设 B 的中断状态清除。最后,CPU 会在 ISR 返回之前清除中断位锁存器。因此在整个中断处理过程中,如果外设 A 触发了中断,该中断会因 CPU 清除中断位锁存器而丢失。
IRAM-safe 中断处理程序
ESP_INTR_FLAG_IRAM
flag 注册的中断处理程序始终在 IRAM(并从 DRAM 读取其所有数据)中运行,因此在擦除和写入 flash 时无需禁用。
这对于需要保证最小执行延迟的中断来说非常有用,因为 flash 写入和擦除操作可能很慢(擦除可能需要数十毫秒或数百毫秒才能完成)。
如果中断被频繁调用,可以将中断处理程序保留在 IRAM 中,避免 flash cache 丢失。
有关更多详细信息,请参阅 SPI flash API 相关文档。
排除中断分配故障
CPU 中断在大多数 Espressif SoC 上都是有限的资源。因此,一个运行的程序有可能耗尽 CPU 中断,例如初始化多个外设驱动程序的情况。这通常导致驱动程序的初始化函数返回 ESP_ERR_NOT_FOUND
错误。
这种情况下,可使用 esp_intr_dump()
函数打印中断列表及其状态。此函数输出通常如下:
CPU 0 interrupt status:
Int Level Type Status
0 1 Level Reserved
1 1 Level Reserved
2 1 Level Used: RTC_CORE
3 1 Level Used: TG0_LACT_LEVEL
...
输出列含义如下:
Int
:CPU 中断输入编号。通常不直接在软件中使用,仅作为参考。Level
:已分配中断的优先级级别。空闲的中断具有标记*
。Type
:已分配中断的类型(电平或边缘中断)。空闲的中断具有标记*
。Status
:中断的可能状态:Reserved
:中断在硬件层面保留,或由 ESP-IDF 的某些部分保留。不能使用esp_intr_alloc()
分配。Used: <source>
:中断已分配并连接到单个外设。Shared: <source1> <source2> ...
:中断已分配并连接到多个外设。参见本文档 多个处理程序共用一个中断源 章节。Free
:中断未分配,可以由esp_intr_alloc()
使用。
如果已确认应用程序的确用完了中断,可组合采用下列建议解决问题:
找到可接受更高延迟的中断,并用
ESP_INTR_FLAG_SHARED
flag (或与ESP_INTR_FLAG_LOWMED
进行 OR 运算)分配这些中断。对两个或更多外设使用此 flag 能让它们使用单个中断输入,从而为其他外设节约中断输入。参见 多个处理程序共用一个中断源。检查是否有些外设驱动程序不需要一直启用,并按需将其初始化或取消初始化。这样可以减少同时分配的中断数量。
API 参考
Header File
This header file can be included with:
#include "esp_intr_types.h"
Macros
-
ESP_INTR_CPU_AFFINITY_TO_CORE_ID(cpu_affinity)
Convert esp_intr_cpu_affinity_t to CPU core ID.
Type Definitions
-
typedef void (*intr_handler_t)(void *arg)
Function prototype for interrupt handler function
-
typedef struct intr_handle_data_t *intr_handle_t
Handle to an interrupt handler
Enumerations
-
enum esp_intr_cpu_affinity_t
Interrupt CPU core affinity.
This type specify the CPU core that the peripheral interrupt is connected to.
Values:
-
enumerator ESP_INTR_CPU_AFFINITY_AUTO
Install the peripheral interrupt to ANY CPU core, decided by on which CPU the interrupt allocator is running.
-
enumerator ESP_INTR_CPU_AFFINITY_0
Install the peripheral interrupt to CPU core 0.
-
enumerator ESP_INTR_CPU_AFFINITY_1
Install the peripheral interrupt to CPU core 1.
-
enumerator ESP_INTR_CPU_AFFINITY_AUTO
Header File
This header file can be included with:
#include "esp_intr_alloc.h"
Functions
Mark an interrupt as a shared interrupt.
This will mark a certain interrupt on the specified CPU as an interrupt that can be used to hook shared interrupt handlers to.
- 参数
intno -- The number of the interrupt (0-31)
cpu -- CPU on which the interrupt should be marked as shared (0 or 1)
is_in_iram -- Shared interrupt is for handlers that reside in IRAM and the int can be left enabled while the flash cache is disabled.
- 返回
ESP_ERR_INVALID_ARG if cpu or intno is invalid ESP_OK otherwise
-
esp_err_t esp_intr_reserve(int intno, int cpu)
Reserve an interrupt to be used outside of this framework.
This will mark a certain interrupt on the specified CPU as reserved, not to be allocated for any reason.
- 参数
intno -- The number of the interrupt (0-31)
cpu -- CPU on which the interrupt should be marked as shared (0 or 1)
- 返回
ESP_ERR_INVALID_ARG if cpu or intno is invalid ESP_OK otherwise
-
esp_err_t esp_intr_alloc(int source, int flags, intr_handler_t handler, void *arg, intr_handle_t *ret_handle)
Allocate an interrupt with the given parameters.
This finds an interrupt that matches the restrictions as given in the flags parameter, maps the given interrupt source to it and hooks up the given interrupt handler (with optional argument) as well. If needed, it can return a handle for the interrupt as well.
The interrupt will always be allocated on the core that runs this function.
If ESP_INTR_FLAG_IRAM flag is used, and handler address is not in IRAM or RTC_FAST_MEM, then ESP_ERR_INVALID_ARG is returned.
- 参数
source -- The interrupt source. One of the ETS_*_INTR_SOURCE interrupt mux sources, as defined in soc/soc.h, or one of the internal ETS_INTERNAL_*_INTR_SOURCE sources as defined in this header.
flags -- An ORred mask of the ESP_INTR_FLAG_* defines. These restrict the choice of interrupts that this routine can choose from. If this value is 0, it will default to allocating a non-shared interrupt of level 1, 2 or 3. If this is ESP_INTR_FLAG_SHARED, it will allocate a shared interrupt of level 1. Setting ESP_INTR_FLAG_INTRDISABLED will return from this function with the interrupt disabled.
handler -- The interrupt handler. Must be NULL when an interrupt of level >3 is requested, because these types of interrupts aren't C-callable.
arg -- Optional argument for passed to the interrupt handler
ret_handle -- Pointer to an intr_handle_t to store a handle that can later be used to request details or free the interrupt. Can be NULL if no handle is required.
- 返回
ESP_ERR_INVALID_ARG if the combination of arguments is invalid. ESP_ERR_NOT_FOUND No free interrupt found with the specified flags ESP_OK otherwise
-
esp_err_t esp_intr_alloc_intrstatus(int source, int flags, uint32_t intrstatusreg, uint32_t intrstatusmask, intr_handler_t handler, void *arg, intr_handle_t *ret_handle)
Allocate an interrupt with the given parameters.
This essentially does the same as esp_intr_alloc, but allows specifying a register and mask combo. For shared interrupts, the handler is only called if a read from the specified register, ANDed with the mask, returns non-zero. By passing an interrupt status register address and a fitting mask, this can be used to accelerate interrupt handling in the case a shared interrupt is triggered; by checking the interrupt statuses first, the code can decide which ISRs can be skipped
- 参数
source -- The interrupt source. One of the ETS_*_INTR_SOURCE interrupt mux sources, as defined in soc/soc.h, or one of the internal ETS_INTERNAL_*_INTR_SOURCE sources as defined in this header.
flags -- An ORred mask of the ESP_INTR_FLAG_* defines. These restrict the choice of interrupts that this routine can choose from. If this value is 0, it will default to allocating a non-shared interrupt of level 1, 2 or 3. If this is ESP_INTR_FLAG_SHARED, it will allocate a shared interrupt of level 1. Setting ESP_INTR_FLAG_INTRDISABLED will return from this function with the interrupt disabled.
intrstatusreg -- The address of an interrupt status register
intrstatusmask -- A mask. If a read of address intrstatusreg has any of the bits that are 1 in the mask set, the ISR will be called. If not, it will be skipped.
handler -- The interrupt handler. Must be NULL when an interrupt of level >3 is requested, because these types of interrupts aren't C-callable.
arg -- Optional argument for passed to the interrupt handler
ret_handle -- Pointer to an intr_handle_t to store a handle that can later be used to request details or free the interrupt. Can be NULL if no handle is required.
- 返回
ESP_ERR_INVALID_ARG if the combination of arguments is invalid. ESP_ERR_NOT_FOUND No free interrupt found with the specified flags ESP_OK otherwise
-
esp_err_t esp_intr_free(intr_handle_t handle)
Disable and free an interrupt.
Use an interrupt handle to disable the interrupt and release the resources associated with it. If the current core is not the core that registered this interrupt, this routine will be assigned to the core that allocated this interrupt, blocking and waiting until the resource is successfully released.
备注
When the handler shares its source with other handlers, the interrupt status bits it's responsible for should be managed properly before freeing it. see
esp_intr_disable
for more details. Please do not call this function inesp_ipc_call_blocking
.- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
- 返回
ESP_ERR_INVALID_ARG the handle is NULL ESP_FAIL failed to release this handle ESP_OK otherwise
-
int esp_intr_get_cpu(intr_handle_t handle)
Get CPU number an interrupt is tied to.
- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
- 返回
The core number where the interrupt is allocated
-
int esp_intr_get_intno(intr_handle_t handle)
Get the allocated interrupt for a certain handle.
- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
- 返回
The interrupt number
-
esp_err_t esp_intr_disable(intr_handle_t handle)
Disable the interrupt associated with the handle.
备注
For local interrupts (ESP_INTERNAL_* sources), this function has to be called on the CPU the interrupt is allocated on. Other interrupts have no such restriction.
When several handlers sharing a same interrupt source, interrupt status bits, which are handled in the handler to be disabled, should be masked before the disabling, or handled in other enabled interrupts properly. Miss of interrupt status handling will cause infinite interrupt calls and finally system crash.
- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
- 返回
ESP_ERR_INVALID_ARG if the combination of arguments is invalid. ESP_OK otherwise
-
esp_err_t esp_intr_enable(intr_handle_t handle)
Enable the interrupt associated with the handle.
备注
For local interrupts (ESP_INTERNAL_* sources), this function has to be called on the CPU the interrupt is allocated on. Other interrupts have no such restriction.
- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
- 返回
ESP_ERR_INVALID_ARG if the combination of arguments is invalid. ESP_OK otherwise
-
esp_err_t esp_intr_set_in_iram(intr_handle_t handle, bool is_in_iram)
Set the "in IRAM" status of the handler.
备注
Does not work on shared interrupts.
- 参数
handle -- The handle, as obtained by esp_intr_alloc or esp_intr_alloc_intrstatus
is_in_iram -- Whether the handler associated with this handle resides in IRAM. Handlers residing in IRAM can be called when cache is disabled.
- 返回
ESP_ERR_INVALID_ARG if the combination of arguments is invalid. ESP_OK otherwise
-
void esp_intr_noniram_disable(void)
Disable interrupts that aren't specifically marked as running from IRAM.
-
void esp_intr_noniram_enable(void)
Re-enable interrupts disabled by esp_intr_noniram_disable.
-
void esp_intr_enable_source(int inum)
enable the interrupt source based on its number
- 参数
inum -- interrupt number from 0 to 31
-
void esp_intr_disable_source(int inum)
disable the interrupt source based on its number
- 参数
inum -- interrupt number from 0 to 31
-
static inline int esp_intr_flags_to_level(int flags)
Get the lowest interrupt level from the flags.
- 参数
flags -- The same flags that pass to
esp_intr_alloc_intrstatus
API
-
static inline int esp_intr_level_to_flags(int level)
Get the interrupt flags from the supplied level (priority)
- 参数
level -- The interrupt priority level
Macros
-
ESP_INTR_FLAG_LEVEL1
Interrupt allocation flags.
These flags can be used to specify which interrupt qualities the code calling esp_intr_alloc* needs. Accept a Level 1 interrupt vector (lowest priority)
-
ESP_INTR_FLAG_LEVEL2
Accept a Level 2 interrupt vector.
-
ESP_INTR_FLAG_LEVEL3
Accept a Level 3 interrupt vector.
-
ESP_INTR_FLAG_LEVEL4
Accept a Level 4 interrupt vector.
-
ESP_INTR_FLAG_LEVEL5
Accept a Level 5 interrupt vector.
-
ESP_INTR_FLAG_LEVEL6
Accept a Level 6 interrupt vector.
-
ESP_INTR_FLAG_NMI
Accept a Level 7 interrupt vector (highest priority)
-
ESP_INTR_FLAG_SHARED
Interrupt can be shared between ISRs.
-
ESP_INTR_FLAG_EDGE
Edge-triggered interrupt.
-
ESP_INTR_FLAG_IRAM
ISR can be called if cache is disabled.
-
ESP_INTR_FLAG_INTRDISABLED
Return with this interrupt disabled.
-
ESP_INTR_FLAG_LOWMED
Low and medium prio interrupts. These can be handled in C.
-
ESP_INTR_FLAG_HIGH
High level interrupts. Need to be handled in assembly.
-
ESP_INTR_FLAG_LEVELMASK
Mask for all level flags.
-
ETS_INTERNAL_TIMER0_INTR_SOURCE
Platform timer 0 interrupt source.
The esp_intr_alloc* functions can allocate an int for all ETS_*_INTR_SOURCE interrupt sources that are routed through the interrupt mux. Apart from these sources, each core also has some internal sources that do not pass through the interrupt mux. To allocate an interrupt for these sources, pass these pseudo-sources to the functions.
-
ETS_INTERNAL_TIMER1_INTR_SOURCE
Platform timer 1 interrupt source.
-
ETS_INTERNAL_TIMER2_INTR_SOURCE
Platform timer 2 interrupt source.
-
ETS_INTERNAL_SW0_INTR_SOURCE
Software int source 1.
-
ETS_INTERNAL_SW1_INTR_SOURCE
Software int source 2.
-
ETS_INTERNAL_PROFILING_INTR_SOURCE
Int source for profiling.
-
ETS_INTERNAL_UNUSED_INTR_SOURCE
Interrupt is not assigned to any source.
-
ETS_INTERNAL_INTR_SOURCE_OFF
Provides SystemView with positive IRQ IDs, otherwise scheduler events are not shown properly
-
ESP_INTR_ENABLE(inum)
Enable interrupt by interrupt number
-
ESP_INTR_DISABLE(inum)
Disable interrupt by interrupt number