Hi Sudeep, > -----Original Message----- > From: Sudeep Holla [mailto:sudeep.holla@xxxxxxx] > Sent: Thursday, March 01, 2018 6:44 AM > To: Jolly Shah <JOLLYS@xxxxxxxxxx> > Cc: ard.biesheuvel@xxxxxxxxxx; mingo@xxxxxxxxxx; > gregkh@xxxxxxxxxxxxxxxxxxx; matt@xxxxxxxxxxxxxxxxxxx; > hkallweit1@xxxxxxxxx; keescook@xxxxxxxxxxxx; > dmitry.torokhov@xxxxxxxxx; michal.simek@xxxxxxxxxx; robh+dt@xxxxxxxxxx; > mark.rutland@xxxxxxx; Sudeep Holla <sudeep.holla@xxxxxxx>; Rajan Vaja > <RAJANV@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; Jolly Shah > <JOLLYS@xxxxxxxxxx> > Subject: Re: [PATCH v5 3/4] drivers: firmware: xilinx: Add sysfs interface > > > > 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@xxxxxxxxxx> > > Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx> > > --- > > .../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@xxxxxxxxxx> > > +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. > These are for general use. Information being passed can be application specific. Sysfs call underneath maps to EEMI ioctl call to read/write these registers. > > + 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 ? There are total 8 such registers. 4 are reserved for customer application. Other 4 are being used by Xilinx sw products like FSBL. FSBL is using it to pass handoff information to other master. > > > + 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@xxxxxxxxxx> > > +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 ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
