Messages in this thread | | | Subject | Re: [PATCH v5 3/4] drivers: firmware: xilinx: Add sysfs interface | From | Sudeep Holla <> | Date | Thu, 1 Mar 2018 14:44:11 +0000 |
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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 <jollys@xilinx.com> > Signed-off-by: Rajan Vaja <rajanv@xilinx.com> > --- > .../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" <jollys@xilinx.com> > +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" <jollys@xilinx.com> > +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
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