Encapsulate the start method parsing in a single function
and add needed debug printouts.
It eliminates small issue with useless double checking for
ACPI_TPM2_MEMORY_MAPPED.

Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
---
 drivers/char/tpm/tpm_crb.c | 65 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 50 insertions(+), 15 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index aa0ef742ac03..aeec313384d7 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -381,6 +381,52 @@ out:
        return ret;
 }
 
+/**
+ * crb_start_method - parse starting method
+ *
+ * @device: acpi device
+ * @sm: starting method
+ *
+ * Return 0 if supported starting method was not found
+ *    CRB_FL_CRB_START or CRB_FL_ACPI_START otherwise
+ */
+static unsigned int crb_start_method(struct acpi_device *device, u32 sm)
+{
+       struct device *dev = &device->dev;
+       u32 flags;
+
+       switch (sm) {
+       /* Should the FIFO driver handle this? */
+       case ACPI_TPM2_MEMORY_MAPPED:
+               dev_dbg(dev, "starting method[%d]: MM\n", sm);
+               return 0;
+       case ACPI_TPM2_COMMAND_BUFFER:
+               flags = CRB_FL_CRB_START;
+               dev_dbg(dev, "starting method[%d]: CB\n", sm);
+               break;
+       case ACPI_TPM2_START_METHOD:
+               flags = CRB_FL_ACPI_START;
+               dev_dbg(dev, "starting method[%d]: SM\n", sm);
+               break;
+       case ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD:
+               flags = CRB_FL_ACPI_START;
+               dev_dbg(dev, "starting method[%d]: CB w/ SM\n",
+                       sm);
+               break;
+       default:
+               return 0;
+       }
+
+       /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
+        * report only ACPI start but in practice seems to require both
+        * ACPI start and CRB start.
+        */
+       if (!strcmp(acpi_device_hid(device), "MSFT0101"))
+               flags |= CRB_FL_CRB_START;
+
+       return flags;
+}
+
 static int crb_acpi_add(struct acpi_device *device)
 {
        struct acpi_table_tpm2 *buf;
@@ -388,7 +434,7 @@ static int crb_acpi_add(struct acpi_device *device)
        struct tpm_chip *chip;
        struct device *dev = &device->dev;
        acpi_status status;
-       u32 sm;
+       unsigned int sm;
        int rc;
 
        status = acpi_get_table(ACPI_SIG_TPM2, 1,
@@ -398,26 +444,15 @@ static int crb_acpi_add(struct acpi_device *device)
                return -EINVAL;
        }
 
-       /* Should the FIFO driver handle this? */
-       sm = buf->start_method;
-       if (sm == ACPI_TPM2_MEMORY_MAPPED)
+       sm = crb_start_method(device, buf->start_method);
+       if (!sm)
                return -ENODEV;
 
        priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
 
-       /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
-        * report only ACPI start but in practice seems to require both
-        * ACPI start and CRB start.
-        */
-       if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
-           !strcmp(acpi_device_hid(device), "MSFT0101"))
-               priv->flags |= CRB_FL_CRB_START;
-
-       if (sm == ACPI_TPM2_START_METHOD ||
-           sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
-               priv->flags |= CRB_FL_ACPI_START;
+       priv->flags = sm;
 
        rc = crb_map_io(device, priv, buf);
        if (rc)
-- 
2.7.4


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