flashrom-gerrit April 2020

flashrom-gerrit@flashrom.org

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Change in flashrom[master]: i2c_helper: Add support for the Linux I2C subsystem
by Shiyu Sun (Code Review) 01 Apr '20

01 Apr '20

Shiyu Sun has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/39686 ) Change subject: i2c_helper: Add support for the Linux I2C subsystem ...................................................................... i2c_helper: Add support for the Linux I2C subsystem See https://www.kernel.org/doc/Documentation/i2c/ for details. This creates common interface for I2C access functions, and adds implementation for linux I2C functions. Signed-off-by: Shiyu Sun <sshiyu(a)chromium.org> Change-Id: Ie0487824dfb71970bede17f617dbbb30ddf78c12 --- M Makefile A i2c_helper.h A i2c_helper_linux.c M meson.build M meson_options.txt 5 files changed, 241 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/86/39686/1 diff --git a/Makefile b/Makefile index 28ceab6..aa77a64 100644 --- a/Makefile +++ b/Makefile @@ -418,6 +418,10 @@ endif endif +ifeq ($(TARGET_OS), Linux) +CONFIG_LINUX_I2C_HELPER = yes +endif + ############################################################################### # General architecture-specific settings. # Like above for the OS, below we verify user-supplied options depending on the target architecture. @@ -1047,6 +1051,11 @@ PROGRAMMER_OBJS += ni845x_spi.o endif +ifeq ($(CONFIG_LINUX_I2C_HELPER), yes) +LIB_OBJS += i2c_helper_linux.o +FEATURE_CFLAGS += -D'CONFIG_LINUX_I2C_HELPER=1' +endif + ifneq ($(NEED_SERIAL), ) LIB_OBJS += serial.o custom_baud.o endif diff --git a/i2c_helper.h b/i2c_helper.h new file mode 100644 index 0000000..80dc836 --- /dev/null +++ b/i2c_helper.h @@ -0,0 +1,112 @@ +/* + * This file is part of the flashrom project. + * + * Copyright (C) 2020 The Chromium OS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef I2C_HELPER_H +#define I2C_HELPER_H + +#include <inttypes.h> + +/** + * An convinent structure that contains the buffer size and the buffer + * pointer. Used to wrap buffer details while doing the I2C data + * transfer on both input and output. It is the client's responsibility + * to use i2c_buffer_t_fill to initialize this struct instead of + * trying to construct it directly. + */ +typedef struct { + void *buf; + uint16_t len; +} i2c_buffer_t; + +/** + * i2c_buffer_t_fill - fills in the i2c_buffer_t + * + * @i2c_buf: pointer to the be constructed. + * @buf: buffer contains data to be included in i2c_buffer_t. + * @len: length of buffer to be included in i2c_buffer_t. + * + * This function takes in a pointer to an initialized i2c_buffer_t + * object with related information, and fill in the i2c_buffer_t with + * some validation applied. The function does allow initialization with + * NULL buffer but will make sure len == 0 in such case. + * + * returns 0 on success, <0 to indicate failure + */ +static inline int i2c_buffer_t_fill(i2c_buffer_t *i2c_buf, void *buf, uint16_t len) +{ + if (!i2c_buf || (!buf && len)) + return -1; + + i2c_buf -> buf = buf; + i2c_buf -> len = len; + + return 0; +} + +/** + * i2c_open - opens the target I2C device and set the I2C slave address + * + * @bus: I2C bus number of the target device. + * @addr: I2C slave address. + * @force: whether to force set the I2C slave address. + * + * This function returns a file descriptor for the target device. It is + * the client's responsibility to pass the return value to i2c_close to + * clean up. + * + * returns fd of target device on success, <0 to indicate failure + */ +int i2c_open(int bus, uint16_t addr, int force); + +/** + * i2c_close - closes the file descriptor returned by i2c_open + * + * @fd: file descriptor to be closed. + * + * It is the client's responsibility to set fd = -1 when it is + * done with it. + * + * returns 0 on success, <0 to indicate failure + */ +int i2c_close(int fd); + +/** + * i2c_read - reads data from the I2C device + * + * @fd: file descriptor of the target device. + * @addr: I2C slave address of the target device. + * @buf_read: data struct includes reading buffer and size. + * + * This function does accept empty read and do nothing on such case. + * + * returns read length on success, <0 to indicate failure + */ +int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf_read); + +/** + * i2c_write - writes command/data into the I2C device + * + * @fd: file descriptor of the target device. + * @addr: I2C slave address of the target device. + * @buf_write: data struct includes writting buffer and size. + * + * This function does accept empty write and do nothing on such case. + * + * returns wrote length on success, <0 to indicate failure. + */ +int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf_write); + +#endif /* !I2C_HELPER_H */ diff --git a/i2c_helper_linux.c b/i2c_helper_linux.c new file mode 100644 index 0000000..0703518 --- /dev/null +++ b/i2c_helper_linux.c @@ -0,0 +1,113 @@ +/* + * This file is part of the flashrom project. + * + * Copyright (C) 2020 The Chromium OS Authors + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <errno.h> +#include <stdio.h> +#include <string.h> +#include <sys/fcntl.h> +#include <sys/ioctl.h> +#include <unistd.h> + +#include <stdlib.h> +#include <linux/i2c.h> +#include <linux/i2c-dev.h> + +#include "flash.h" +#include "i2c_helper.h" + +#define I2C_DEV_PREFIX "/dev/i2c-" +#define I2C_MAX_BUS 255 + +int i2c_close(int fd) +{ + return fd == -1 ? 0 : close(fd); +} + +int i2c_open(int bus, uint16_t addr, int force) +{ + int ret = -1; + int fd = -1; + + /* Maximum i2c bus number is 255(3 char), +1 for null terminated string. */ + int path_len = strlen(I2C_DEV_PREFIX) + 4; + int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE; + + if (bus < 0 || bus > I2C_MAX_BUS) { + msg_perr("Invalid I2C bus %d.\n", bus); + return ret; + } + + char *dev = calloc(1, path_len); + if (!dev) { + msg_perr("Unable to allocate space for device name of len %d: %s.\n", + path_len, strerror(errno)); + goto linux_i2c_open_err; + } + + ret = snprintf(dev, path_len, "%s%d", I2C_DEV_PREFIX, bus); + if (ret < 0) { + msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno)); + goto linux_i2c_open_err; + } + + fd = open(dev, O_RDWR); + if (fd < 0) { + msg_perr("Unable to open I2C device %s: %s.\n", dev, strerror(errno)); + ret = fd; + goto linux_i2c_open_err; + } + + ret = ioctl(fd, request, addr); + if (ret < 0) { + msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); + i2c_close(fd); + goto linux_i2c_open_err; + } + +linux_i2c_open_err: + if (dev) + free(dev); + + return ret ? ret : fd; +} + +int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf) +{ + if (buf->len == 0) + return 0; + + int ret = ioctl(fd, I2C_SLAVE, addr); + if (ret < 0) { + msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); + return ret; + } + + return read(fd, buf->buf, buf->len); +} + +int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf) +{ + if (buf->len == 0) + return 0; + + int ret = ioctl(fd, I2C_SLAVE, addr); + if (ret < 0) { + msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); + return ret; + } + + return write(fd, buf->buf, buf->len); +} diff --git a/meson.build b/meson.build index 8bb3e65..b586d9a 100644 --- a/meson.build +++ b/meson.build @@ -63,6 +63,7 @@ config_serprog = get_option('config_serprog') config_usbblaster_spi = get_option('config_usbblaster_spi') config_stlinkv3_spi = get_option('config_stlinkv3_spi') +config_linux_i2c_helper = get_option('config_linux_i2c_helper') cargs = [] deps = [] @@ -290,6 +291,11 @@ cargs += '-DCONFIG_BITBANG_SPI=1' endif +if config_linux_i2c_helper + srcs += 'i2c_helper_linux.c' + cargs += '-DCONFIG_LINUX_I2C_HELPER=1' +endif + # raw memory, MSR or PCI port I/O access if need_raw_access srcs += 'hwaccess.c' diff --git a/meson_options.txt b/meson_options.txt index 2831271..ff4a786 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -35,3 +35,4 @@ option('config_serprog', type : 'boolean', value : true, description : 'serprog') option('config_usbblaster_spi', type : 'boolean', value : true, description : 'Altera USB-Blaster dongles') option('config_stlinkv3_spi', type : 'boolean', value : true, description : 'STMicroelectronics STLINK-V3') +option('config_linux_i2c_helper', type: 'boolean', value : true, description : 'Linux I2C control') -- To view, visit https://review.coreboot.org/c/flashrom/+/39686 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: Ie0487824dfb71970bede17f617dbbb30ddf78c12 Gerrit-Change-Number: 39686 Gerrit-PatchSet: 1 Gerrit-Owner: Shiyu Sun <sshiyu(a)google.com> Gerrit-MessageType: newchange

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flashrom-gerrit April 2020