[PATCH v4 6/7] platform/chrome: Create sysfs attributes for the ChromeOS EC

Javier Martinez Canillas
2015-01-29T13:39:04Z

From: Bill Richardson <wfrichar@chromium.org>

This adds the first few sysfs attributes for the Chrome OS EC. These
controls are made available under /sys/devices/virtual/chromeos/cros_ec

flashinfo - display current flash info
reboot - tell the EC to reboot in various ways
version - information about the EC software and hardware

Future changes will build on this to add additional controls.

>From a root shell, you should be able to do things like this:

cd /sys/devices/virtual/chromeos/cros_ec
cat flashinfo
cat version
echo rw > reboot
cat version
echo ro > reboot
cat version
echo rw > reboot
cat version
echo cold > reboot

That last command will reboot the AP too.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---

Changes since v3: None.

Changes since v2: None.

Changes since v1:
- Moved from drivers/mfd to drivers/platform/chrome. Suggested by Lee Jones.
- Modify to use the fixed-size arrays for cros_ec_command in and out buffers.
---
drivers/platform/chrome/Makefile | 3 +-
drivers/platform/chrome/cros_ec_dev.c | 4 +
drivers/platform/chrome/cros_ec_dev.h | 3 +
drivers/platform/chrome/cros_ec_sysfs.c | 271 ++++++++++++++++++++++++++++++++
4 files changed, 280 insertions(+), 1 deletion(-)
create mode 100644 drivers/platform/chrome/cros_ec_sysfs.c

diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 10f1361a97b4..3e7980b9bc86 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -1,4 +1,5 @@

obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o
obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
-obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_dev.o
+cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o
+obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o
diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
index 94c1442d5104..33f37ad36892 100644
--- a/drivers/platform/chrome/cros_ec_dev.c
+++ b/drivers/platform/chrome/cros_ec_dev.c
@@ -198,6 +198,9 @@ static int ec_device_probe(struct platform_device *pdev)
return retval;
}

+ /* Initialize extra interfaces */
+ ec_dev_sysfs_init(ec);
+
return 0;
}

@@ -205,6 +208,7 @@ static int ec_device_remove(struct platform_device *pdev)
{
struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);

+ ec_dev_sysfs_remove(ec);
device_destroy(cros_class, MKDEV(ec_major, 0));
cdev_del(&ec->cdev);
return 0;
diff --git a/drivers/platform/chrome/cros_ec_dev.h b/drivers/platform/chrome/cros_ec_dev.h
index 15c54c4c5531..f03613290ecf 100644
--- a/drivers/platform/chrome/cros_ec_dev.h
+++ b/drivers/platform/chrome/cros_ec_dev.h
@@ -44,4 +44,7 @@ struct cros_ec_readmem {
#define CROS_EC_DEV_IOCXCMD _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
#define CROS_EC_DEV_IOCRDMEM _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)

+void ec_dev_sysfs_init(struct cros_ec_device *);
+void ec_dev_sysfs_remove(struct cros_ec_device *);
+
#endif /* _CROS_EC_DEV_H_ */
diff --git a/drivers/platform/chrome/cros_ec_sysfs.c b/drivers/platform/chrome/cros_ec_sysfs.c
new file mode 100644
index 000000000000..fb62ab6cc659
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_sysfs.c
@@ -0,0 +1,271 @@
+/*
+ * cros_ec_sysfs - expose the Chrome OS EC through sysfs
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define pr_fmt(fmt) "cros_ec_sysfs: " fmt
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/kobject.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/stat.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include "cros_ec_dev.h"
+
+/* Accessor functions */
+
+static ssize_t show_ec_reboot(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int count = 0;
+
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "ro|rw|cancel|cold|disable-jump|hibernate");
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ " [at-shutdown]\n");
+ return count;
+}
+
+static ssize_t store_ec_reboot(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ static const struct {
+ const char * const str;
+ uint8_t cmd;
+ uint8_t flags;
+ } words[] = {
+ {"cancel", EC_REBOOT_CANCEL, 0},
+ {"ro", EC_REBOOT_JUMP_RO, 0},
+ {"rw", EC_REBOOT_JUMP_RW, 0},
+ {"cold", EC_REBOOT_COLD, 0},
+ {"disable-jump", EC_REBOOT_DISABLE_JUMP, 0},
+ {"hibernate", EC_REBOOT_HIBERNATE, 0},
+ {"at-shutdown", -1, EC_REBOOT_FLAG_ON_AP_SHUTDOWN},
+ };
+ struct cros_ec_command msg = { 0 };
+ struct ec_params_reboot_ec *param =
+ (struct ec_params_reboot_ec *)msg.outdata;
+ int got_cmd = 0, offset = 0;
+ int i;
+ int ret;
+ struct cros_ec_device *ec = dev_get_drvdata(dev);
+
+ param->flags = 0;
+ while (1) {
+ /* Find word to start scanning */
+ while (buf[offset] && isspace(buf[offset]))
+ offset++;
+ if (!buf[offset])
+ break;
+
+ for (i = 0; i < ARRAY_SIZE(words); i++) {
+ if (!strncasecmp(words[i].str, buf+offset,
+ strlen(words[i].str))) {
+ if (words[i].flags) {
+ param->flags |= words[i].flags;
+ } else {
+ param->cmd = words[i].cmd;
+ got_cmd = 1;
+ }
+ break;
+ }
+ }
+
+ /* On to the next word, if any */
+ while (buf[offset] && !isspace(buf[offset]))
+ offset++;
+ }
+
+ if (!got_cmd)
+ return -EINVAL;
+
+ msg.command = EC_CMD_REBOOT_EC;
+ msg.outsize = sizeof(param);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ return ret;
+ if (msg.result != EC_RES_SUCCESS) {
+ dev_dbg(ec->dev, "EC result %d\n", msg.result);
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static ssize_t show_ec_version(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ static const char * const image_names[] = {"unknown", "RO", "RW"};
+ struct ec_response_get_version *r_ver;
+ struct ec_response_get_chip_info *r_chip;
+ struct ec_response_board_version *r_board;
+ struct cros_ec_command msg = { 0 };
+ int ret;
+ int count = 0;
+ struct cros_ec_device *ec = dev_get_drvdata(dev);
+
+ /* Get versions. RW may change. */
+ msg.command = EC_CMD_GET_VERSION;
+ msg.insize = sizeof(*r_ver);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ return ret;
+ if (msg.result != EC_RES_SUCCESS)
+ return scnprintf(buf, PAGE_SIZE,
+ "ERROR: EC returned %d\n", msg.result);
+
+ r_ver = (struct ec_response_get_version *)msg.indata;
+ /* Strings should be null-terminated, but let's be sure. */
+ r_ver->version_string_ro[sizeof(r_ver->version_string_ro) - 1] = '\0';
+ r_ver->version_string_rw[sizeof(r_ver->version_string_rw) - 1] = '\0';
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "RO version: %s\n", r_ver->version_string_ro);
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "RW version: %s\n", r_ver->version_string_rw);
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Firmware copy: %s\n",
+ (r_ver->current_image < ARRAY_SIZE(image_names) ?
+ image_names[r_ver->current_image] : "?"));
+
+ /* Get build info. */
+ msg.command = EC_CMD_GET_BUILD_INFO;
+ msg.insize = sizeof(msg.indata);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Build info: XFER ERROR %d\n", ret);
+ else if (msg.result != EC_RES_SUCCESS)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Build info: EC error %d\n", msg.result);
+ else {
+ msg.indata[sizeof(msg.indata) - 1] = '\0';
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Build info: %s\n", msg.indata);
+ }
+
+ /* Get chip info. */
+ msg.command = EC_CMD_GET_CHIP_INFO;
+ msg.insize = sizeof(*r_chip);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Chip info: XFER ERROR %d\n", ret);
+ else if (msg.result != EC_RES_SUCCESS)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Chip info: EC error %d\n", msg.result);
+ else {
+ r_chip = (struct ec_response_get_chip_info *)msg.indata;
+
+ r_chip->vendor[sizeof(r_chip->vendor) - 1] = '\0';
+ r_chip->name[sizeof(r_chip->name) - 1] = '\0';
+ r_chip->revision[sizeof(r_chip->revision) - 1] = '\0';
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Chip vendor: %s\n", r_chip->vendor);
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Chip name: %s\n", r_chip->name);
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Chip revision: %s\n", r_chip->revision);
+ }
+
+ /* Get board version */
+ msg.command = EC_CMD_GET_BOARD_VERSION;
+ msg.insize = sizeof(*r_board);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Board version: XFER ERROR %d\n", ret);
+ else if (msg.result != EC_RES_SUCCESS)
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Board version: EC error %d\n", msg.result);
+ else {
+ r_board = (struct ec_response_board_version *)msg.indata;
+
+ count += scnprintf(buf + count, PAGE_SIZE - count,
+ "Board version: %d\n",
+ r_board->board_version);
+ }
+
+ return count;
+}
+
+static ssize_t show_ec_flashinfo(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ec_response_flash_info *resp;
+ struct cros_ec_command msg = { 0 };
+ int ret;
+ struct cros_ec_device *ec = dev_get_drvdata(dev);
+
+ /* The flash info shouldn't ever change, but ask each time anyway. */
+ msg.command = EC_CMD_FLASH_INFO;
+ msg.insize = sizeof(*resp);
+ ret = cros_ec_cmd_xfer(ec, &msg);
+ if (ret < 0)
+ return ret;
+ if (msg.result != EC_RES_SUCCESS)
+ return scnprintf(buf, PAGE_SIZE,
+ "ERROR: EC returned %d\n", msg.result);
+
+ resp = (struct ec_response_flash_info *)msg.indata;
+
+ return scnprintf(buf, PAGE_SIZE,
+ "FlashSize %d\nWriteSize %d\n"
+ "EraseSize %d\nProtectSize %d\n",
+ resp->flash_size, resp->write_block_size,
+ resp->erase_block_size, resp->protect_block_size);
+}
+
+/* Module initialization */
+
+static DEVICE_ATTR(reboot, S_IWUSR | S_IRUGO, show_ec_reboot, store_ec_reboot);
+static DEVICE_ATTR(version, S_IRUGO, show_ec_version, NULL);
+static DEVICE_ATTR(flashinfo, S_IRUGO, show_ec_flashinfo, NULL);
+
+static struct attribute *__ec_attrs[] = {
+ &dev_attr_reboot.attr,
+ &dev_attr_version.attr,
+ &dev_attr_flashinfo.attr,
+ NULL,
+};
+
+static struct attribute_group ec_attr_group = {
+ .attrs = __ec_attrs,
+};
+
+void ec_dev_sysfs_init(struct cros_ec_device *ec)
+{
+ int error;
+
+ error = sysfs_create_group(&ec->vdev->kobj, &ec_attr_group);
+ if (error)
+ pr_warn("failed to create group: %d\n", error);
+}
+
+void ec_dev_sysfs_remove(struct cros_ec_device *ec)
+{
+ sysfs_remove_group(&ec->vdev->kobj, &ec_attr_group);
+}
--
2.1.3