[patch v27 0/4] JTAG driver introduction

[Henbin Chang]

 Hi Oleksandr,

Sorry to bother you.
May I know how do you verify the JTAG driver workable?

Thanks.
BRs,
Henbin


> When a need raise up to use JTAG interface for system's devices
> programming or CPU debugging, usually the user layer
> application implements jtag protocol by bit-bang or using a
> proprietary connection to vendor hardware.
> This method can be slow and not generic.
>
> We propose to implement general JTAG interface and infrastructure
> to communicate with user layer application. In such way, we can
> have the standard JTAG interface core part and separation from
> specific HW implementation.
> This allow new capability to debug the CPU or program system's
> device via BMC without additional devices nor cost. This patch purpose is
> to add JTAG master core infrastructure by
> defining new JTAG class and provide generic JTAG interface
> to allow hardware specific drivers to connect this interface.
> This will enable all JTAG drivers to use the common interface
> part and will have separate for hardware implementation. The JTAG (Joint
> Test Action Group) core driver provides minimal generic
> JTAG interface, which can be used by hardware specific JTAG master
> controllers. By providing common interface for the JTAG controllers,
> user space device programing is hardware independent.
>
> Modern SoC which in use for embedded system' equipped with
> internal JTAG master interface.
> This interface is used for programming and debugging system's
> hardware components, like CPLD, FPGA, CPU, voltage and
> industrial controllers.
> Firmware for such devices can be upgraded through JTAG interface during
> Runtime. The JTAG standard support for multiple devices programming,
> is in case their lines are daisy-chained together. For example, systems
> which equipped with host CPU, BMC SoC or/and
> number of programmable devices are capable to connect a pin and
> select system components dynamically for programming and debugging,
> This is using by the BMC which is equipped with internal SoC master
> controller.
> For example: BMC JTAG master --> pin selected to CPLDs chain for
> programming (filed
> upgrade, production)
> BMC JTAG master --> pin selected to voltage monitors for programming
> (field upgrade, production)
> BMC JTAG master --> pin selected to host CPU (on-site debugging
> and developers debugging) For example, we can have application in user
> space which using calls
> to JTAG driver executes CPLD programming directly from SVF file
>
> The JTAG standard (IEEE 1149.1) defines the next connector pins:
> - TDI (Test Data In);
> - TDO (Test Data Out);
> - TCK (Test Clock);
> - TMS (Test Mode Select);
> - TRST (Test Reset) (Optional); The SoC equipped with JTAG master
> controller, performs
> device programming on command or vector level. For example
> a file in a standard SVF (Serial Vector Format) that contains
> boundary scan vectors, can be used by sending each vector
> to the JTAG interface and the JTAG controller will execute
> the programming. Initial version provides the system calls set for:
> - SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
> - SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
> - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> number of clocks. SoC which are not equipped with JTAG master interface,
> can be built
> on top of JTAG core driver infrastructure, by applying bit-banging of
> TDI, TDO, TCK and TMS pins within the hardware specific driver. Oleksandr
> Shamray (4):
> drivers: jtag: Add JTAG core driver
> drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master
> driver
> Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx
> families JTAG master driver
> Documentation: jtag: Add ABI documentation
> Documentation/ABI/testing/jtag-dev | 23 +
> .../devicetree/bindings/jtag/aspeed-jtag.txt | 22 +
> Documentation/ioctl/ioctl-number.txt | 2 +
> Documentation/jtag/overview | 27 +
> Documentation/jtag/transactions | 109 +++
> MAINTAINERS | 10 +
> drivers/Kconfig | 2 +
> drivers/Makefile | 1 +
> drivers/jtag/Kconfig | 31 +
> drivers/jtag/Makefile | 2 +
> drivers/jtag/jtag-aspeed.c | 747 ++++++++++++++++++++
> drivers/jtag/jtag.c | 274 +++++++
> include/linux/jtag.h | 41 ++
> include/uapi/linux/jtag.h | 109 +++
> 14 files changed, 1400 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/ABI/testing/jtag-dev
> create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
> create mode 100644 Documentation/jtag/overview
> create mode 100644 Documentation/jtag/transactions
> create mode 100644 drivers/jtag/Kconfig
> create mode 100644 drivers/jtag/Makefile
> create mode 100644 drivers/jtag/jtag-aspeed.c
> create mode 100644 drivers/jtag/jtag.c
> create mode 100644 include/linux/jtag.h
> create mode 100644 include/uapi/linux/jtag.h
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