Skip to content

Update PRU UART documentation #708

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
jmenti wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Update PRU UART documentation #708

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
3018cf2
fix(linux): Remove PRU SW UART from TOC
jmenti May 14, 2026
cd1bacd
fix(linux): Enable PRU HW UART doc for am62x and am64x
jmenti May 14, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 0 additions & 1 deletion configs/AM335X/AM335X_linux_toc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,6 @@ linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RPMsg
linux/Foundational_Components/PRU-ICSS/RPMsg_Quick_Start_Guide
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU-ICSS_Ethernet
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pru-sw-uart
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart
linux/Foundational_Components/PRU-ICSS-Hardware
linux/Foundational_Components/PRU-ICSS/PRU-EVMs
Expand Down
1 change: 0 additions & 1 deletion configs/AM437X/AM437X_linux_toc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,6 @@ linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RPMsg
linux/Foundational_Components/PRU-ICSS/RPMsg_Quick_Start_Guide
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU-ICSS_Ethernet
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pru-sw-uart
linux/Foundational_Components/PRU-ICSS-Hardware
linux/Foundational_Components/PRU-ICSS/PRU-EVMs
linux/Foundational_Components/PRU-ICSS-Training
Expand Down
1 change: 0 additions & 1 deletion configs/AM57X/AM57X_linux_toc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -94,7 +94,6 @@ linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RPMsg
linux/Foundational_Components/PRU-ICSS/RPMsg_Quick_Start_Guide
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU-ICSS_Ethernet
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pru-sw-uart
linux/Foundational_Components/PRU-ICSS-Hardware
linux/Foundational_Components/PRU-ICSS/PRU-EVMs
linux/Foundational_Components/PRU-ICSS-Training
Expand Down
1 change: 1 addition & 0 deletions configs/AM62X/AM62X_linux_toc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,7 @@ linux/Foundational_Components_PRU_Subsystem
linux/Foundational_Components/PRU-ICSS-Linux-Drivers
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RPMsg
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart
linux/Foundational_Components/PRU-ICSS/RPMsg_Quick_Start_Guide
linux/Foundational_Components/PRU-ICSS-Hardware
linux/Foundational_Components/PRU-ICSS/PRU-EVMs
Expand Down
1 change: 1 addition & 0 deletions configs/AM64X/AM64X_linux_toc.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,7 @@ linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RemoteProc
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU_ICSSG_Ethernet
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU_ICSSG_Ethernet_Switch
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/RPMsg
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart
linux/Foundational_Components/PRU-ICSS/Linux_Drivers/PRU_ICSSG_XDP
linux/Foundational_Components/PRU-ICSS/RPMsg_Quick_Start_Guide
linux/Foundational_Components/PRU-ICSS-Hardware
Expand Down
22 changes: 12 additions & 10 deletions source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,27 +3,32 @@

.. rubric:: Introduction

As of Processor SDK v7.1, Linux supports the PRU UART peripheral within the
PRU-ICSS, which is based on the industry standard TL16C550.
The kernel driver is at drivers/tty/serial/8250/8250_pruss.c.
Linux supports the PRU HW UART peripheral within the

Check warning on line 6 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'UART') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'UART') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 6, "column": 27}}}, "severity": "INFO"}

Check warning on line 6 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'PRU') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'PRU') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 6, "column": 20}}}, "severity": "INFO"}

.. ifconfig:: CONFIG_part_variant in ('AM62X')

Programmable Real-Time Unit Subsystem (PRUSS)

.. ifconfig:: CONFIG_part_variant in ('AM64X')

.. rubric:: Support Devices
Programmable Real-Time Unit and Industrial Communication Subsystem - Gigabit (PRU-ICSSG)

Check warning on line 14 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'PRU') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'PRU') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 14, "column": 82}}}, "severity": "INFO"}

- |__PART_FAMILY_DEVICE_NAMES__|
.. ifconfig:: CONFIG_part_variant in ('AM335X', 'AM437X', 'AM57XX')

Programmable Real-Time Unit Subsystem and Industrial Communication Subsystem (PRU-ICSS)

Check warning on line 18 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'ICSS') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'ICSS') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 18, "column": 86}}}, "severity": "INFO"}

which is based on the industry standard TL16C550.

Check warning on line 20 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.PassiveVoice] 'is based' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

Raw Output:
{"message": "[RedHat.PassiveVoice] 'is based' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 20, "column": 7}}}, "severity": "INFO"}

Check warning on line 20 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.

Raw Output:
{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 20, "column": 1}}}, "severity": "INFO"}
The kernel driver is at drivers/tty/serial/8250/8250_pruss.c.

Check warning on line 21 in source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst

View workflow job for this annotation

GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Slash] Use either 'or' or 'and' in 'drivers/tty'

Raw Output:
{"message": "[RedHat.Slash] Use either 'or' or 'and' in 'drivers/tty'", "location": {"path": "source/linux/Foundational_Components/PRU-ICSS/Linux_Drivers/pruss-uart.rst", "range": {"start": {"line": 21, "column": 25}}}, "severity": "WARNING"}

.. rubric:: Supported Driver Features

- Baud rates up to 12Mbps
- Hardware flow control


.. rubric:: Unsupported Driver Features

- DMA support


.. rubric:: Kernel Config

The PRUSS UART Linux kernel driver depends on the PRU-ICSS kernel drivers. So
Expand Down Expand Up @@ -61,7 +66,6 @@
status = "okay";
};


.. rubric:: Driver Usage

Once the driver is probed, kernel log shows the following message.
Expand All @@ -78,5 +82,3 @@

The index in ttyS1 could vary depending on the serial alias configuration
in the device tree.


Loading