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Subject[char-misc 3.6] mei: add mei_quirk_probe function
Date
The main purpose of this function is to exclude ME devices
without support for MEI/HECI interface from binding

Currently affected systems are C600/X79 based servers
that expose PCI device even though it doesn't supported ME Interface.
MEI driver accessing such nonfunctional device can corrupt
the system.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
drivers/misc/mei/main.c | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 0923302..7422c76 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -925,6 +925,27 @@ static struct miscdevice mei_misc_device = {
};

/**
+ * mei_quirk_probe - probe for devices that doesn't valid ME interface
+ * @pdev: PCI device structure
+ * @ent: entry into pci_device_table
+ *
+ * returns true if ME Interface is valid, false otherwise
+ */
+static bool __devinit mei_quirk_probe(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ u32 reg;
+ if (ent->device == MEI_DEV_ID_PBG_1) {
+ pci_read_config_dword(pdev, 0x48, &reg);
+ /* make sure that bit 9 is up and bit 10 is down */
+ if ((reg & 0x600) == 0x200) {
+ dev_info(&pdev->dev, "Device doesn't have valid ME Interface\n");
+ return false;
+ }
+ }
+ return true;
+}
+/**
* mei_probe - Device Initialization Routine
*
* @pdev: PCI device structure
@@ -939,6 +960,12 @@ static int __devinit mei_probe(struct pci_dev *pdev,
int err;

mutex_lock(&mei_mutex);
+
+ if (!mei_quirk_probe(pdev, ent)) {
+ err = -ENODEV;
+ goto end;
+ }
+
if (mei_device) {
err = -EEXIST;
goto end;
--
1.7.4.4


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