diff options
| -rw-r--r-- | extra/i2c_pseudo/Makefile | 11 | ||||
| -rwxr-xr-x | extra/i2c_pseudo/check_stream_open.sh | 23 | ||||
| -rw-r--r-- | extra/i2c_pseudo/i2c-pseudo.c | 13 |
3 files changed, 46 insertions, 1 deletions
diff --git a/extra/i2c_pseudo/Makefile b/extra/i2c_pseudo/Makefile index c8dcb1e3b4..f7fda6e2de 100644 --- a/extra/i2c_pseudo/Makefile +++ b/extra/i2c_pseudo/Makefile @@ -1,9 +1,20 @@ +# Copyright 2020 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. +# +# Makefile for i2c-pseudo module. Typical usage: +# $ make +# $ sudo make modules_install +# $ make clean + obj-m := i2c-pseudo.o .PHONY: all all: modules +CFLAGS_i2c-pseudo.o += "-DHAVE_STREAM_OPEN=$(shell "$M"/check_stream_open.sh)" + .DEFAULT: $(MAKE) -C /lib/modules/$(shell uname -r)/build \ M=$(shell pwd) \ diff --git a/extra/i2c_pseudo/check_stream_open.sh b/extra/i2c_pseudo/check_stream_open.sh new file mode 100755 index 0000000000..da802cb282 --- /dev/null +++ b/extra/i2c_pseudo/check_stream_open.sh @@ -0,0 +1,23 @@ +#!/bin/sh +# +# Copyright 2020 The Chromium OS Authors. All rights reserved. +# Use of this source code is governed by a BSD-style license that can be +# found in the LICENSE file. +# +# This checks whether stream_open symbol is available from the target kernel. +# +# Output meanings: +# -1 : stream_open is not available +# 0 : unknown whether or not stream_open is available +# 1 : stream_open is available + +symbols="$(< "/lib/modules/$(uname -r)/build/Module.symvers" \ + awk '{print $2}' | grep -E '^(nonseekable_open|stream_open)$')" + +if echo "${symbols}" | grep -q '^stream_open$'; then + echo 1 +elif echo "${symbols}" | grep -q '^nonseekable_open$'; then + echo -1 +else + echo 0 +fi diff --git a/extra/i2c_pseudo/i2c-pseudo.c b/extra/i2c_pseudo/i2c-pseudo.c index 69fc9dbc52..bbe702a14c 100644 --- a/extra/i2c_pseudo/i2c-pseudo.c +++ b/extra/i2c_pseudo/i2c-pseudo.c @@ -2205,8 +2205,19 @@ static int i2cp_cdev_open(struct inode *inodep, struct file *filep) /* Is there any way to find this through @inodep? */ this_pseudo = i2cp_device; - /* I2C pseudo adapter controllers are not seekable. */ + /* + * HAVE_STREAM_OPEN value meanings: + * -1 : stream_open() is not available + * 0 : unknown if stream_open() is or is not available + * 1 : stream_open() is available + */ +#if HAVE_STREAM_OPEN >= 0 + /* I2C pseudo adapter controllers are non-seekable pure I/O streams. */ stream_open(inodep, filep); +#else + /* I2C pseudo adapter controllers are not seekable. */ + nonseekable_open(inodep, filep); +#endif /* Refuse fsnotify events. Modeled after /dev/ptmx implementation. */ filep->f_mode |= FMODE_NONOTIFY; |