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| -rw-r--r-- | Documentation/ABI/stable/sysfs-driver-firmware-zynqmp | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp index c3fec3c835af..ac8c2314deee 100644 --- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp +++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp @@ -254,3 +254,36 @@ Description: The expected result is 500. Users: Xilinx + +What: /sys/devices/platform/firmware\:zynqmp-firmware/csu_registers/* +Date: May 2026 +KernelVersion: 7.2 +Contact: "Ronak Jain" <ronak.jain@amd.com> +Description: + Read/Write CSU (Configuration Security Unit) registers. + + This interface provides dynamic access to CSU registers that are + discovered from the firmware at boot time using PM_QUERY_DATA API. + + The supported registers are: + + - multiboot: CSU_MULTI_BOOT register + - idcode: CSU_IDCODE register (read-only) + - pcap-status: CSU_PCAP_STATUS register (read-only) + + Read operations use the existing IOCTL_READ_REG API. + Write operations use the existing IOCTL_MASK_WRITE_REG API. + + The firmware enforces access control - read-only registers will reject + write attempts even though the sysfs permissions show write access. + + Usage for reading:: + + # cat /sys/devices/platform/firmware\:zynqmp-firmware/csu_registers/multiboot + # cat /sys/devices/platform/firmware\:zynqmp-firmware/csu_registers/idcode + + Usage for writing (mask and value are in hexadecimal):: + + # echo 0xFFFFFFF 0x0 > /sys/devices/platform/firmware\:zynqmp-firmware/csu_registers/multiboot + +Users: Xilinx/AMD |