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doc: kernel: interrupts: zero-latency IRQ update

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Add description how to enable zero-latency interrupt in the application
code. Previous docs described only the Kconfig and not the flag.

Signed-off-by: Martin Jäger <martin@libre.solar>
This commit is contained in:
Martin Jäger 2020-10-19 13:39:44 +02:00 committed by Carles Cufí
parent 4d6bc47ac3
commit ba9fd65a4b
1 changed files with 6 additions and 3 deletions
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9
doc/reference/kernel/other/interrupts.rst
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@ -165,7 +165,10 @@ The kernel addresses such use-cases by allowing interrupts with critical
latency constraints to execute at a priority level that cannot be blocked
by interrupt locking. These interrupts are defined as
*zero-latency interrupts*. The support for zero-latency interrupts requires
:option:`CONFIG_ZERO_LATENCY_IRQS` to be enabled.
:option:`CONFIG_ZERO_LATENCY_IRQS` to be enabled. In addition to that, the
flag :c:macro:`IRQ_ZERO_LATENCY` must be passed to :c:macro:`IRQ_CONNECT` or
:c:macro:`IRQ_DIRECT_CONNECT` macros to configure the particular interrupt
with zero latency.
Zero-latency interrupts are expected to be used to manage hardware events
directly, and not to interoperate with the kernel code at all. They should
@ -227,7 +230,7 @@ The following code defines and enables an ISR.
#define MY_DEV_PRIO 2 /* device uses interrupt priority 2 */
/* argument passed to my_isr(), in this case a pointer to the device */
#define MY_ISR_ARG DEVICE_GET(my_device)
#define MY_IRQ_FLAGS 0 /* IRQ flags. Unused on non-x86 */
#define MY_IRQ_FLAGS 0 /* IRQ flags */
void my_isr(void *arg)
{
@ -293,7 +296,7 @@ The following code demonstrates a direct ISR:
#define MY_DEV_IRQ 24 /* device uses IRQ 24 */
#define MY_DEV_PRIO 2 /* device uses interrupt priority 2 */
/* argument passed to my_isr(), in this case a pointer to the device */
#define MY_IRQ_FLAGS 0 /* IRQ flags. Unused on non-x86 */
#define MY_IRQ_FLAGS 0 /* IRQ flags */
ISR_DIRECT_DECLARE(my_isr)
{