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Date: Fri, 14 Dec 2018 17:18:37 -0700
From: Nick Crews <ncrews@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: Duncan Laurie <dlaurie@...gle.com>, Nick Crews <ncrews@...gle.com>,
Olof Johansson <olof@...om.net>,
Benson Leung <bleung@...omium.org>
Subject: [RFC PATCH 04/10] CHROMIUM: wilco_ec: Add support for raw commands in sysfs
From: Duncan Laurie <dlaurie@...gle.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@...gle.com>
Signed-off-by: Nick Crews <ncrews@...gle.com>
---
drivers/platform/chrome/Kconfig | 10 ++
drivers/platform/chrome/wilco_ec.h | 6 +
drivers/platform/chrome/wilco_ec_mailbox.c | 6 -
drivers/platform/chrome/wilco_ec_sysfs.c | 126 +++++++++++++++++++++
4 files changed, 142 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 4168d5e6bedc..05c6d9a00395 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -61,6 +61,16 @@ 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
+ default n
+ 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.
+
config CROS_EC_CTL
tristate
diff --git a/drivers/platform/chrome/wilco_ec.h b/drivers/platform/chrome/wilco_ec.h
index 699f4cf744dc..0b3dec4e2830 100644
--- a/drivers/platform/chrome/wilco_ec.h
+++ b/drivers/platform/chrome/wilco_ec.h
@@ -20,6 +20,12 @@
#include <linux/device.h>
#include <linux/kernel.h>
+/* Normal commands have a maximum 32 bytes of data */
+#define EC_MAILBOX_DATA_SIZE 32
+
+/* Extended commands have 256 bytes of response data */
+#define EC_MAILBOX_DATA_SIZE_EXTENDED 256
+
#define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
#define WILCO_EC_FLAG_EXTENDED_DATA BIT(1) /* EC returns 256 data bytes */
#define WILCO_EC_FLAG_RAW_REQUEST BIT(2) /* Do not trim request data */
diff --git a/drivers/platform/chrome/wilco_ec_mailbox.c b/drivers/platform/chrome/wilco_ec_mailbox.c
index 414ea0a8ad03..1cb34b7280fd 100644
--- a/drivers/platform/chrome/wilco_ec_mailbox.c
+++ b/drivers/platform/chrome/wilco_ec_mailbox.c
@@ -44,12 +44,6 @@
/* Version of EC protocol */
#define EC_MAILBOX_PROTO_VERSION 3
-/* Normal commands have a maximum 32 bytes of data */
-#define EC_MAILBOX_DATA_SIZE 32
-
-/* Extended commands have 256 bytes of response data */
-#define EC_MAILBOX_DATA_SIZE_EXTENDED 256
-
/* Number of header bytes to be counted as data bytes */
#define EC_MAILBOX_DATA_EXTRA 2
diff --git a/drivers/platform/chrome/wilco_ec_sysfs.c b/drivers/platform/chrome/wilco_ec_sysfs.c
index f9ae6cef6169..eeebd4ba4a39 100644
--- a/drivers/platform/chrome/wilco_ec_sysfs.c
+++ b/drivers/platform/chrome/wilco_ec_sysfs.c
@@ -23,6 +23,126 @@
#define EC_INFO_SIZE 9
#define EC_COMMAND_STEALTH_MODE 0xfc
+#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];
+
+/*
+ * raw: write a raw command and return the result
+ *
+ * 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 1:
+ * # echo 00 f0 38 00 01 00 > raw
+ * # cat raw
+ * 00 38 31 34 34 66 00 00 00 00 00 00 00 00 00 00 00...
+ */
+
+static ssize_t raw_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t count = 0;
+
+ if (raw_response_size) {
+ int i;
+
+ for (i = 0; i < raw_response_size; ++i)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "%02x ", raw_response_data[i]);
+
+ count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
+
+ /* Only return response the first time it is read */
+ raw_response_size = 0;
+ }
+
+ return count;
+}
+
+static ssize_t 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 nul-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;
+}
+
+#endif /* CONFIG_WILCO_EC_SYSFS_RAW */
+
struct ec_info {
u8 index;
const char *label;
@@ -102,10 +222,16 @@ static ssize_t stealth_mode_store(struct device *dev,
static DEVICE_ATTR_RO(version);
static DEVICE_ATTR_WO(stealth_mode);
+#ifdef CONFIG_WILCO_EC_SYSFS_RAW
+static DEVICE_ATTR_RW(raw);
+#endif
static struct attribute *wilco_ec_attrs[] = {
&dev_attr_version.attr,
&dev_attr_stealth_mode.attr,
+#ifdef CONFIG_WILCO_EC_SYSFS_RAW
+ &dev_attr_raw.attr,
+#endif
NULL
};
ATTRIBUTE_GROUPS(wilco_ec);
--
2.20.0.405.gbc1bbc6f85-goog
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