On 20/02/18 19:21, Jolly Shah wrote:
> Add Firmware-ggs sysfs interface which provides read/write
> interface to global storage registers.
>
> Signed-off-by: Jolly Shah <[email protected]>
> Signed-off-by: Rajan Vaja <[email protected]>
> ---
> .../ABI/stable/sysfs-driver-zynqmp-firmware | 50 ++++
> drivers/firmware/xilinx/zynqmp/Makefile | 2 +-
> drivers/firmware/xilinx/zynqmp/firmware-ggs.c | 297
> +++++++++++++++++++++
> drivers/firmware/xilinx/zynqmp/firmware.c | 13 +
> include/linux/firmware/xilinx/zynqmp/firmware.h | 2 +
> 5 files changed, 363 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
> create mode 100644 drivers/firmware/xilinx/zynqmp/firmware-ggs.c
>
> diff --git a/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
> b/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
> new file mode 100644
> index 0000000..b04727a
> --- /dev/null
> +++ b/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
> @@ -0,0 +1,50 @@
> +What: /sys/devices/platform/zynqmp-firmware/ggs> +Date:
> January 2018
> +KernelVersion: 4.15.0
> +Contact: "Jolly Shah" <[email protected]>
> +Description:
> + Read/Write PMU global general storage register value,
> + GLOBAL_GEN_STORAGE{0:3}.
> + Global general storage register that can be used
> + by system to pass information between masters.
> +
What kind of information ? Is there any semantics for that ?
Why does EEMI lack APIs for that if it's critical, giving access to
such information to userspace may not be good idea.
> + The register is reset during system or power-on
> + resets. Three registers are used by the FSBL and
> + other Xilinx software products: GLOBAL_GEN_STORAGE{4:6}.
> +
FSBL ?
For what is it used ?
> + Usage:
> + # cat /sys/.../zynqmp-firmware/ggs0
> + # echo <mask> <value> > /sys/.../zynqmp-firmware/ggs0
> +
> + Example:
> + # cat /sys/.../zynqmp-firmware/ggs0
> + # echo 0xFFFFFFFF 0x1234ABCD > /sys/.../zynqmp-firmware/ggs0
> +
> +Users: Xilinx
> +
> +What: /sys/devices/platform/zynqmp-firmware/pggs*
> +Date: January 2018
> +KernelVersion: 4.15.0
> +Contact: "Jolly Shah" <[email protected]>
> +Description:
> + Read/Write PMU persistent global general storage register
> + value, PERS_GLOB_GEN_STORAGE{0:3}.
> + Persistent global general storage register that
> + can be used by system to pass information between
> + masters.
> +
Ditto
> + This register is only reset by the power-on reset
> + and maintains its value through a system reset.
> + Four registers are used by the FSBL and other Xilinx
> + software products: PERS_GLOB_GEN_STORAGE{4:7}.
> + Register is reset only by a POR reset.
> +
Ditto
--
Regards,
Sudeep
