110 lines
3.9 KiB
C
110 lines
3.9 KiB
C
/*
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* include/linux/jtag.h
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*
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* Written Aug 2009 by Davide Rizzo <elpa.rizzo@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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* This driver manages one or more jtag chains controlled by host pins.
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* Jtag chains must be defined during setup using jtag_platdata structs.
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* All operations must be done from user programs using ioctls to /dev/jtag
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* Typical operation sequence is:
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* - open() the device (normally /dev/jtag)
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* - ioctl JTAG_GET_DEVICES reads how many devices in the chain
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* (repeat for each chip in the chain)
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* - ioctl JTAG_GET_ID identifies the chip
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* - ioctl JTAG_SET_IR_LENGTH sets the instruction register length
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* Before accessing the data registers, instruction registers' lenghtes
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* MUST be programmed for all chips.
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* After this initialization, you can execute JTAG_IR_WR, JTAG_DR_RD, JTAG_DR_WR
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* commands in any sequence.
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*/
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#ifndef __JTAG_H__
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#define __JTAG_H__
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/* Controller's gpio_tdi must be connected to last device's gpio_tdo */
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/* Controller's gpio_tdo must be connected to first device's gpio_tdi */
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struct jtag_platdata {
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unsigned int gpio_tclk;
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unsigned int gpio_tms;
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unsigned int gpio_tdi;
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unsigned int gpio_tdo;
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unsigned int gpio_trst;
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int use_gpio_trst;
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};
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#define JTAG_NAME "jtag"
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/* structures used for passing arguments to ioctl */
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struct jtag_rd_id {
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int device; /* Device in the chain */
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unsigned long id;
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};
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struct jtag_cmd {
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int device; /* Device in the chain (-1 = all devices) */
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unsigned int bitlen; /* Bit length of the register to be transfered */
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unsigned long *data; /* Data to be transfered */
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};
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/* Use 'j' as magic number */
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#define JTAG_IOC_MAGIC 'j'
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/* ioctl commands */
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/* Resets jtag chain status, arg is ignored */
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#define JTAG_RESET _IO(JTAG_IOC_MAGIC, 0)
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/* Returns the number of devices in the jtag chain, arg is ignored. */
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#define JTAG_GET_DEVICES _IO(JTAG_IOC_MAGIC, 1)
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/* arg must point to a jtag_rd_id structure.
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Fills up the id field with ID of selected device */
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#define JTAG_GET_ID _IOR(JTAG_IOC_MAGIC, 2, struct jtag_rd_id)
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/* arg must point to a struct jtag_cmd.
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Programs the Instruction Register length of specified device at bitlen value.
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*data is ignored. */
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#define JTAG_SET_IR_LENGTH _IOW(JTAG_IOC_MAGIC, 3, struct jtag_rd_id)
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/* arg must point to a struct jtag_cmd.
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Writes *data in the Instruction Register of selected device, and BYPASS
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instruction into Instruction Registers of all other devices in the chain.
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If device == -1, the Instruction Registers of all devices are programmed
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to the same value.
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bitlen is always ignored, before using this command you have to program all
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Instruction Register's lengthes with JTAG_SET_IR_LENGTH command. */
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#define JTAG_IR_WR _IOW(JTAG_IOC_MAGIC, 4, struct jtag_cmd)
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/* arg must point to a struct jtag_cmd.
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Reads data register of selected device, with length bitlen */
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#define JTAG_DR_RD _IOR(JTAG_IOC_MAGIC, 5, struct jtag_cmd)
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/* arg must point to a struct jtag_cmd.
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Writes data register of selected device, with length bitlen.
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If device == -1, writes same data on all devices. */
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#define JTAG_DR_WR _IOW(JTAG_IOC_MAGIC, 6, struct jtag_cmd)
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/* Generates arg pulses on TCLK pin */
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#define JTAG_CLK _IOW(JTAG_IOC_MAGIC, 7, unsigned int *)
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#define JTAG_IOC_MAXNR 9
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#endif /* __JTAG_H__ */
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