coreboot-libre-fam15h-rdimm/3rdparty/chromeec/extra/usb_spi/stm32spi.py

141 lines
3.8 KiB
Python
Executable File

#!/usr/bin/env python2
# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
# Test program to access SPI via stm32 raiden debug spi.
import usb
import usb.core
import usb.util
class SSpiBus(object):
"""SPI bus class to access devices on the bus.
Usage:
bus = SSpiBus()
# read 1 byte from register(0x16)
bus.wr_rd([0x16], 1)
# write 2 bytes to register(0x20)
bus.wr_rd([0x20, 0x01, 0x02])
Instance Variables:
_dev: pyUSB device object
_read_ep: pyUSB read endpoint for this interface
_write_ep: pyUSB write endpoint for this interface
"""
def __init__(self, vendor=0x18d1,
product=0x501a, interface=2, serialname=None):
# Find the stm32.
dev = usb.core.find(idVendor=vendor, idProduct=product)
if dev is None:
raise Exception("SPI", "USB device not found")
print "Found stm32: %04x:%04x" % (vendor, product)
self._dev = dev
# Get an endpoint instance.
cfg = dev.get_active_configuration()
intf = usb.util.find_descriptor(cfg, bInterfaceNumber=interface)
self._intf = intf
print "InterfaceNumber: %s" % intf.bInterfaceNumber
read_ep = usb.util.find_descriptor(
intf,
# match the first IN endpoint
custom_match=\
lambda e: \
usb.util.endpoint_direction(e.bEndpointAddress) == \
usb.util.ENDPOINT_IN
)
self._read_ep = read_ep
print "Reader endpoint: 0x%x" % read_ep.bEndpointAddress
write_ep = usb.util.find_descriptor(
intf,
# match the first OUT endpoint
custom_match=\
lambda e: \
usb.util.endpoint_direction(e.bEndpointAddress) == \
usb.util.ENDPOINT_OUT
)
self._write_ep = write_ep
print "Writer endpoint: 0x%x" % write_ep.bEndpointAddress
self.enable(True)
print "Set up stm32 spi"
def enable(self, enable):
# USB_RIR_OUT = 0 | USB_TYPE_VENDOR = (0x02 << 5) |
# USB_RECIP_INTERFACE = 0x01
bmRequestType = 0x41
# USB_SPI_REQ_ENABLE = 0x0000, USB_SPI_REQ_DISABLE = 0x0001
if enable:
bmRequest = 0x0
else:
bmRequest = 0x1
print "ctrl_transfer(0x%x, 0x%x, 0, 0x%x, null)" % (
bmRequestType, bmRequest, self._intf.bInterfaceNumber)
ret = self._dev.ctrl_transfer(
bmRequestType, bmRequest, 0, self._intf.bInterfaceNumber, '')
print "ctrl_transfer ret - %s" % ret
def wr_rd(self, write_list, read_count=None):
"""Implements hdctools wr_rd() interface.
This function writes byte values list to I2C device, then reads
byte values from the same device.
Args:
write_list: list of output byte values [0~255].
read_count: number of byte values to read from device.
Interface:
write: [write_count, read_count, data ... ]
read: [data .. ]
"""
print "SSpi.wr_rd(write_list=%s, read_count=%s)" % (
write_list, read_count)
# Clean up args from python style to correct types.
write_length = 0
if write_list:
write_length = len(write_list)
if not read_count:
read_count = 0
# Send wr_rd command to stm32.
cmd = [write_length, read_count] + write_list
print "WR: %s" % cmd
ret = self._write_ep.write(cmd, 100)
print "RET: %s " % ret
# Read back response if necessary.
bytesread = self._read_ep.read(read_count + 2, 1000)
print "BYTES: %s " % bytesread
if len(bytesread) < 2:
raise Exception("SPI", "Read status failed.")
print "STATUS: 0x%02x%02x" % (int(bytesread[1]), int(bytesread[0]))
return bytesread[2:]
def main():
bus = SSpiBus()
# write 2 bytes to register(0x20)
bus.wr_rd([0x90, 0x00, 0x00, 0x00], 2)
# read 1 byte from register(0x16)
bus.wr_rd([0x9f], 3)
if __name__ == "__main__":
main()