查看“PWR internal peripheral”的源代码

==Article purpose==
The purpose of this article is to:
* briefly introduce the PWR peripheral and its main features
* indicate the level of security supported by this hardware block
* explain how it can be allocated to the three runtime contexts and linked to the corresponding software components
* explain, when necessary, how to configure the PWR peripheral.

==Peripheral overview==
The '''PWR''' peripheral is used to control the device power supply configuration.<br />

It has 6 input pins (named wakeup pins) which can be programmed to wake the system up from low power. The wakeup pins are listed with '''WKUP''' prefix in the [[STM32MP15 resources#DS12505|STM32MP15 Datasheet]].

These pins can be used by the Cortex<sup>&reg;</sup>-A7 non secure (via Cortex<sup>&reg;</sup>-A7 secure services) or the Cortex<sup>&reg;</sup>-M4.

The PWR peripheral provides 2 output hardware lines named PWR_ON and PWR_LP:
* In [[PMIC hardware components#STPMIC1|STPMIC1]] configuration, PWR_ON allows to select the register bank (active or low power). PWR_LP is not used.
* In the power discrete solution they drive VDDcore which feeds the Cortex<sup>&reg;</sup>-A7, the Cortex<sup>&reg;</sup>-M4 and the peripherals. They also control the DDR power supplies (VDD_DDR, VREF_DDR, VTT_DDR).

===Features===
Refer to the [[STM32MP15 resources#Reference manuals|STM32MP15 reference manuals]] for the complete list of features, and to the software components, introduced below, to see which features are implemented.

===Security support===
The PWR is '''secure aware''' with the security control managed via [[RCC internal peripheral|RCC]] '''TZEN''' bit.

==Peripheral usage and associated software==
===Boot time===
The PWR is closely configured together with [[RCC internal peripheral|RCC]] by all the [[Boot chain overview|boot components]]: the ROM code, the FSBL, the SSBL and up to Linux<sup>&reg;</sup> kernel. Its configuration is carried by the [[Device tree|device tree]].

===Runtime===
====Overview====
The PWR peripheral is shared at runtime:
* the Cortex<sup>&reg;</sup>-A7 secure controls all secure registers (cf. TZEN description above) with [[OP-TEE overview|PWR OP-TEE driver]].
and
* the Cortex<sup>&reg;</sup>-A7 non-secure mainly controls it via the [[Regulator overview|regulator framework]] and the [[Interrupt overview|interrupt framework]] in Linux 
and
* the Cortex<sup>&reg;</sup>-M4 controls it in STM32Cube with [[STM32CubeMP1 architecture|PWR HAL driver]]
<br />
A concurrent control from each context is possible because the described management is realized via independent registers.

====Software frameworks====
{{:Internal_peripherals_software_table_template}}
 | Power & Thermal
 | [[PWR internal peripheral|PWR]]
 | [[OP-TEE_overview|OP-TEE PWR driver]]
 | [[Regulator overview|Linux regulator framework]]
 | [[STM32CubeMP1 architecture|STM32Cube PWR driver]]
 |
 |-
 |}

====Peripheral configuration====
The configuration is applied by the firmware running in the context to which the peripheral is assigned. The configuration can be done alone via the [[STM32CubeMX]] tool for all internal peripherals, and then manually completed (particularly for external peripherals), according to the information given in the corresponding software framework article.

====Peripheral assignment====
{{:Internal_peripherals_assignment_table_template}}
<onlyinclude>
 | rowspan="1" | Power & Thermal
 | rowspan="1" | [[PWR internal peripheral|PWR]]
 | PWR
 | <span title="system peripheral" style="font-size:21px">✓</span>
 | <span title="system peripheral" style="font-size:21px">✓</span>
 | <span title="system peripheral" style="font-size:21px">✓</span>
 |
 |-
</onlyinclude>
 |}

==How to go further==
The PWR is interfaced with the hardware debug port ([[HDP internal peripheral|HDP]]) of the STM32MP15. This link offers the flexibility to observe the main PWR state signals on debug pins.

Please refer to [[STM32MP15 resources#Reference manuals|STM32MP15 reference manuals]] for the exact list of signals that can be monitored.

==References==
<references/>

<noinclude>
[[Category:Power and Thermal peripherals]]
{{ArticleBasedOnModel | Internal peripheral article model}}
{{PublicationRequestId | 9334 | 2018-10-31| AlainF}}
</noinclude>