mei: csc: wake device while reading firmware status

The CSC has firmware status registers in MMIO and they may be
unaccessible while device is suspended.
Wake device while reading firmware status via sysfs.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://patch.msgid.link/20260201094358.1440593-8-alexander.usyskin@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 6f26d516078835f4454e53bb3daf49f613eb933c..54f70f513482fc7911978484277a7fa060ccff4a 100644 (file)
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -4,6 +4,7 @@
  * Intel Management Engine Interface (Intel MEI) Linux driver
  */
 
+#include <linux/cleanup.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
@@ -13,6 +14,7 @@
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/fcntl.h>
+#include <linux/pm_runtime.h>
 #include <linux/poll.h>
 #include <linux/init.h>
 #include <linux/ioctl.h>
@@ -982,14 +984,22 @@ static DEVICE_ATTR_RO(trc);
 static ssize_t fw_status_show(struct device *device,
                struct device_attribute *attr, char *buf)
 {
-       struct mei_device *dev = dev_get_drvdata(device);
+       struct mei_device *mdev = dev_get_drvdata(device);
        struct mei_fw_status fw_status;
        int err, i;
        ssize_t cnt = 0;
 
-       mutex_lock(&dev->device_lock);
-       err = mei_fw_status(dev, &fw_status);
-       mutex_unlock(&dev->device_lock);
+       if (mdev->read_fws_need_resume) {
+               err = pm_runtime_resume_and_get(mdev->parent);
+               if (err) {
+                       dev_err(device, "read fw_status resume error = %d\n", err);
+                       return err;
+               }
+       }
+       scoped_guard(mutex, &mdev->device_lock)
+               err = mei_fw_status(mdev, &fw_status);
+       if (mdev->read_fws_need_resume)
+               pm_runtime_put_autosuspend(mdev->parent);
        if (err) {
                dev_err(device, "read fw_status error = %d\n", err);
                return err;

diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 1796c6793a94e66e27be2a257d07b60445637b6e..d8634a7269901950692a6f28cce3cc961e94a5f7 100644 (file)
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -491,6 +491,7 @@ struct mei_dev_timeouts {
  *
  * @recvd_hw_ready : hw ready message received flag
  * @pg_blocked  : low power mode is not allowed
+ * @read_fws_need_resume: the FW status handler needs HW woken from sleep
  *
  * @wait_hw_ready : wait queue for receive HW ready message form FW
  * @wait_pg     : wait queue for receive PG message from FW
@@ -577,6 +578,7 @@ struct mei_device {
 
        bool recvd_hw_ready;
        bool pg_blocked;
+       bool read_fws_need_resume;
 
        /*
         * waiting queue for receive message from FW

diff --git a/drivers/misc/mei/pci-csc.c b/drivers/misc/mei/pci-csc.c
index 15e170b1e0b68e3bd4ccb1f5ce7e1df111a800e5..70792bf9b3c097e96d2ded3ecd00b4b101e5b63e 100644 (file)
--- a/drivers/misc/mei/pci-csc.c
+++ b/drivers/misc/mei/pci-csc.c
@@ -67,6 +67,8 @@ static int mei_csc_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
        if (!mdev)
                return -ENOMEM;
 
+       mdev->read_fws_need_resume = true;
+
        hw = to_me_hw(mdev);
 
        /*