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    Subject[PATCH v2 4/9] platform/chrome: Add support for raw commands in sysfs
    From
    From: Duncan Laurie <dlaurie@google.com>

    Add a sysfs attribute that allows sending raw commands to the EC.
    This is useful for development and debug but should not be enabled
    in a production environment.

    > echo 00 f0 38 00 03 00 > /sys/bus/platform/devices/GOOG000C\:00/raw
    > cat /sys/bus/platform/devices/GOOG000C\:00/raw
    00 37 33 38 65 64 00...

    Signed-off-by: Duncan Laurie <dlaurie@google.com>
    Signed-off-by: Nick Crews <ncrews@google.com>
    ---

    Changes in v2:
    - Add sysfs documentation
    - rm duplicate EC_MAILBOX_DATA_SIZE defs
    - Make docstrings follow kernel style
    - Fix tags in commit msg
    - Reading raw now includes ASCII translation

    .../ABI/testing/sysfs-platform-wilcoec | 21 ++++
    drivers/platform/chrome/wilco_ec/Kconfig | 9 ++
    drivers/platform/chrome/wilco_ec/legacy.c | 99 +++++++++++++++++++
    drivers/platform/chrome/wilco_ec/legacy.h | 46 +++++++++
    drivers/platform/chrome/wilco_ec/sysfs.c | 6 ++
    5 files changed, 181 insertions(+)

    diff --git a/Documentation/ABI/testing/sysfs-platform-wilcoec b/Documentation/ABI/testing/sysfs-platform-wilcoec
    index 09552338c160..cac2cf11835f 100644
    --- a/Documentation/ABI/testing/sysfs-platform-wilcoec
    +++ b/Documentation/ABI/testing/sysfs-platform-wilcoec
    @@ -24,3 +24,24 @@ Description:
    off and remain off even if activated from the off state.
    External monitors connected to the system are not affected.
    In addition Wireless devices are turned off.
    +
    +What: /sys/bus/platform/devices/GOOG000C\:00/raw
    +Date: January 2019
    +KernelVersion: 4.19
    +Description:
    + Write and read raw mailbox commands to the EC.
    +
    + For writing:
    + Bytes 0-1 indicate the message type:
    + 00 F0 = Execute Legacy Command
    + 00 F2 = Read/Write NVRAM Property
    + Byte 2 provides the command code
    + Bytes 3+ consist of the data passed in the request
    +
    + Example:
    + // Request EC info type 3 (EC firmware build date)
    + $ echo 00 f0 38 00 03 00 > raw
    + // View the result. The decoded ASCII result "12/21/18" is
    + // included after the raw hex.
    + $ cat raw
    + 00 31 32 2f 32 31 2f 31 38 00 38 00 01 00 2f 00 .12/21/18.8...
    diff --git a/drivers/platform/chrome/wilco_ec/Kconfig b/drivers/platform/chrome/wilco_ec/Kconfig
    index f8e6c9e8c5cd..0bd84c98b79b 100644
    --- a/drivers/platform/chrome/wilco_ec/Kconfig
    +++ b/drivers/platform/chrome/wilco_ec/Kconfig
    @@ -21,4 +21,13 @@ config WILCO_EC
    To compile this driver as a module, choose M here: the
    module will be called wilco_ec.

    +config WILCO_EC_SYSFS_RAW
    + bool "Enable raw access to EC via sysfs"
    + depends on WILCO_EC
    + help
    + If you say Y here, you get support for sending raw commands to
    + the Wilco EC via sysfs. These commands do not do any byte
    + manipulation and allow for testing arbitrary commands. This
    + interface is intended for debug only and is disabled by default.
    +
    endif # WILCO_EC_PLATFORM
    diff --git a/drivers/platform/chrome/wilco_ec/legacy.c b/drivers/platform/chrome/wilco_ec/legacy.c
    index 1fdf94d22f57..79bac5dccb39 100644
    --- a/drivers/platform/chrome/wilco_ec/legacy.c
    +++ b/drivers/platform/chrome/wilco_ec/legacy.c
    @@ -11,6 +11,105 @@

    #include "legacy.h"

    +#ifdef CONFIG_WILCO_EC_SYSFS_RAW
    +
    +/* Raw data buffer, large enough to hold extended responses */
    +static size_t raw_response_size;
    +static u8 raw_response_data[EC_MAILBOX_DATA_SIZE_EXTENDED];
    +
    +ssize_t wilco_ec_raw_store(struct device *dev, struct device_attribute *attr,
    + const char *buf, size_t count)
    +{
    + struct wilco_ec_device *ec = dev_get_drvdata(dev);
    + struct wilco_ec_message msg;
    + u8 raw_request_data[EC_MAILBOX_DATA_SIZE];
    + int in_offset = 0;
    + int out_offset = 0;
    + int ret;
    +
    + while (in_offset < count) {
    + char word_buf[EC_MAILBOX_DATA_SIZE];
    + u8 byte;
    + int start_offset = in_offset;
    + int end_offset;
    +
    + /* Find the start of the byte */
    + while (buf[start_offset] && isspace(buf[start_offset]))
    + start_offset++;
    + if (!buf[start_offset])
    + break;
    +
    + /* Find the start of the next byte, if any */
    + end_offset = start_offset;
    + while (buf[end_offset] && !isspace(buf[end_offset]))
    + end_offset++;
    + if (start_offset > count || end_offset > count)
    + break;
    + if (start_offset > EC_MAILBOX_DATA_SIZE ||
    + end_offset > EC_MAILBOX_DATA_SIZE)
    + break;
    +
    + /* Copy to a new NULL terminated string */
    + memcpy(word_buf, buf + start_offset, end_offset - start_offset);
    + word_buf[end_offset - start_offset] = '\0';
    +
    + /* Convert from hex string */
    + ret = kstrtou8(word_buf, 16, &byte);
    + if (ret)
    + break;
    +
    + /* Fill this byte into the request buffer */
    + raw_request_data[out_offset++] = byte;
    + if (out_offset >= EC_MAILBOX_DATA_SIZE)
    + break;
    +
    + in_offset = end_offset;
    + }
    + if (out_offset == 0)
    + return -EINVAL;
    +
    + /* Clear response data buffer */
    + memset(raw_response_data, '\0', EC_MAILBOX_DATA_SIZE_EXTENDED);
    +
    + msg.type = raw_request_data[0] << 8 | raw_request_data[1];
    + msg.flags = WILCO_EC_FLAG_RAW;
    + msg.command = raw_request_data[2];
    + msg.request_data = raw_request_data + 3;
    + msg.request_size = out_offset - 3;
    + msg.response_data = raw_response_data;
    + msg.response_size = EC_MAILBOX_DATA_SIZE;
    +
    + /* Telemetry commands use extended response data */
    + if (msg.type == WILCO_EC_MSG_TELEMETRY) {
    + msg.flags |= WILCO_EC_FLAG_EXTENDED_DATA;
    + msg.response_size = EC_MAILBOX_DATA_SIZE_EXTENDED;
    + }
    +
    + ret = wilco_ec_mailbox(ec, &msg);
    + if (ret < 0)
    + return ret;
    + raw_response_size = ret;
    + return count;
    +}
    +
    +ssize_t wilco_ec_raw_show(struct device *dev, struct device_attribute *attr,
    + char *buf)
    +{
    + ssize_t count = 0;
    +
    + if (raw_response_size) {
    + count = hex_dump_to_buffer(raw_response_data, raw_response_size,
    + 16, 1, buf, PAGE_SIZE, true);
    +
    + /* Only return response the first time it is read */
    + raw_response_size = 0;
    + }
    +
    + return count;
    +}
    +
    +#endif /* CONFIG_WILCO_EC_SYSFS_RAW */
    +
    struct ec_info {
    u8 index;
    const char *label;
    diff --git a/drivers/platform/chrome/wilco_ec/legacy.h b/drivers/platform/chrome/wilco_ec/legacy.h
    index 5c857cb57fa9..340787d25d44 100644
    --- a/drivers/platform/chrome/wilco_ec/legacy.h
    +++ b/drivers/platform/chrome/wilco_ec/legacy.h
    @@ -14,6 +14,52 @@
    #define EC_INFO_SIZE 9
    #define EC_COMMAND_STEALTH_MODE 0xfc

    +#ifdef CONFIG_WILCO_EC_SYSFS_RAW
    +
    +/**
    + * wilco_ec_raw_store() - Write a raw command to EC, store result to view later
    + * @dev: Device representing the EC
    + * @attr: The attribute in question
    + * @buf: Input buffer, format explained below
    + * @count: Number of bytes in input buffer
    + *
    + * Bytes 0-1 indicate the message type:
    + * 00 F0 = Execute Legacy Command
    + * 00 F2 = Read/Write NVRAM Property
    + * Byte 2 provides the command code
    + * Bytes 3+ consist of the data passed in the request
    + *
    + * example: read the EC info type 3 (EC firmware build date):
    + * # echo 00 f0 38 00 03 00 > raw
    + *
    + * After calling this function, read the result by using raw_show()
    + *
    + * Return: Number of bytes consumed from input, negative error code on failure
    + */
    +ssize_t wilco_ec_raw_store(struct device *dev, struct device_attribute *attr,
    + const char *buf, size_t count);
    +
    +/**
    + * wilco_ec_raw_show() - Show result from previous call to raw_store()
    + * @dev: Device representing the EC
    + * @attr: The attribute in question
    + * @buf: Output buffer to be filled
    + *
    + * Example usage:
    + * // Call raw_store(), read EC info type 3 (EC firmware build date)
    + * # echo 00 f0 38 00 03 00 > raw
    + * // Call this function, view the result. The decoded ASCII result
    + * // "12/21/18" is included after the raw hex.
    + * # cat raw
    + * 00 31 32 2f 32 31 2f 31 38 00 38 00 01 00 2f 00 .12/21/18.8.../.
    + *
    + * Return: Number of bytes written to output, negative error code on failure
    + */
    +ssize_t wilco_ec_raw_show(struct device *dev, struct device_attribute *attr,
    + char *buf);
    +
    +#endif /* CONFIG_WILCO_EC_SYSFS_RAW */
    +
    /**
    * wilco_ec_version_show() - Display Wilco Embedded Controller version info
    *
    diff --git a/drivers/platform/chrome/wilco_ec/sysfs.c b/drivers/platform/chrome/wilco_ec/sysfs.c
    index e78a3ec3506b..0611a73fcdce 100644
    --- a/drivers/platform/chrome/wilco_ec/sysfs.c
    +++ b/drivers/platform/chrome/wilco_ec/sysfs.c
    @@ -28,9 +28,15 @@ __ATTR(_name, 0644, wilco_ec_##_name##_show, wilco_ec_##_name##_store)
    /* Make top-level attributes, which will live inside GOOG000C:00/ */
    static struct device_attribute version_attr = WILCO_EC_ATTR_RO(version);
    static struct device_attribute stealth_attr = WILCO_EC_ATTR_WO(stealth_mode);
    +#ifdef CONFIG_WILCO_EC_SYSFS_RAW
    +static struct device_attribute raw_attr = WILCO_EC_ATTR_RW(raw);
    +#endif
    static struct attribute *wilco_ec_toplevel_attrs[] = {
    &version_attr.attr,
    &stealth_attr.attr,
    +#ifdef CONFIG_WILCO_EC_SYSFS_RAW
    + &raw_attr.attr,
    +#endif
    NULL
    };
    ATTRIBUTE_GROUPS(wilco_ec_toplevel);
    --
    2.20.1.97.g81188d93c3-goog
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