"Corona, Ernesto" <ernesto.corona@xxxxxxxxx> writes: > Added document that describe the ABI for JTAG class driver A few comments > diff --git a/Documentation/jtag/index.rst b/Documentation/jtag/index.rst > new file mode 100644 > index 000000000000..8a2761d1c17e > --- /dev/null > +++ b/Documentation/jtag/index.rst Please, let's not create another top-level directory for this; this looks like information that belongs in the userspace-api book. > @@ -0,0 +1,18 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +============================== > +Joint Test Action Group (JTAG) > +============================== > + > +.. toctree:: > + :maxdepth: 1 > + > + jtag-summary > + jtagdev > + > +.. only:: subproject and html > + > + Indices > + ======= > + > + * :ref:`genindex` > diff --git a/Documentation/jtag/jtag-summary.rst b/Documentation/jtag/jtag-summary.rst > new file mode 100644 > index 000000000000..07cfa7a761d7 > --- /dev/null > +++ b/Documentation/jtag/jtag-summary.rst > @@ -0,0 +1,49 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +==================================== > +Linux kernel JTAG support > +==================================== > + > +Introduction to JTAG > +==================== > + > +JTAG is an industry standard for verifying hardware. JTAG provides access to > +many logic signals of a complex integrated circuit, including the device pins. > + > +A JTAG interface is a special interface added to a chip. > +Depending on the version of JTAG, two, four, or five pins are added. > + > +The connector pins are: > + * TDI (Test Data In) > + * TDO (Test Data Out) > + * TCK (Test Clock) > + * TMS (Test Mode Select) > + * TRST (Test Reset) optional > + > +JTAG interface is designed to have two parts - basic core driver and > +hardware specific driver. The basic driver introduces a general interface > +which is not dependent of specific hardware. It provides communication > +between user space and hardware specific driver. > +Each JTAG device is represented as a char device from (jtag0, jtag1, ...). > +Access to a JTAG device is performed through IOCTL calls. > + > +Call flow example: > +:: You can express this more readably as just Call flow example:: > + > + User: open -> /dev/jatgX -> JTAG core driver -> JTAG hardware specific driver > + User: ioctl -> /dev/jtagX -> JTAG core driver -> JTAG hardware specific driver > + User: close -> /dev/jatgX -> JTAG core driver -> JTAG hardware specific driver > + > + > +THANKS TO > +--------- > +Contributors to Linux-JTAG discussions include (in alphabetical order, > +by last name): > + > +- Omar Castro > +- Ernesto Corona > +- Steven Filary > +- Vadim Pasternak > +- Jiri Pirko > +- Oleksandr Shamray > +- Billy Tsai > \ No newline at end of file Files should end in a newline [...] > +=============== ========= ======= ===================================================== > +Bit Field Bit begin Bit end Description > +=============== ========= ======= ===================================================== > +rsvd 25 31 Reserved, not used > +pad data 24 24 Value used for pre and post padding. Either 1 or 0. > +post pad count 12 23 Number of padding bits to be executed after transfer. > +pre pad count 0 11 Number of padding bit to be executed before transfer. > +=============== ========= ======= ===================================================== You should be able to wrap the final column of the table, avoiding these long lines. Thanks, jon
