tpm: two-phase chip management functions

tpm_register_hardware() and tpm_remove_hardware() are called often
before initializing the device. The problem is that the device might
not be fully initialized when it comes visible to the user space.

This patch resolves the issue by diving initialization into two
parts:

- tpmm_chip_alloc() creates struct tpm_chip.

- tpm_chip_register() sets up the character device and sysfs
  attributes.

The framework takes care of freeing struct tpm_chip by using the devres
API. The broken release callback has been wiped. ACPI drivers do not
ever get this callback.

Regards to Jason Gunthorpe for carefully reviewing this part of the
code.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jasob Gunthorpe <jason.gunthorpe@obsidianresearch.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Tested-by: Peter Huewe <peterhuewe@gmx.de>
[phuewe: update to upstream changes]
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
index 441b44e54226..c3b4f5a5ac10 100644
--- a/drivers/char/tpm/xen-tpmfront.c
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -175,9 +175,9 @@ static int setup_chip(struct device *dev, struct tpm_private *priv)
 {
 	struct tpm_chip *chip;
 
-	chip = tpm_register_hardware(dev, &tpm_vtpm);
-	if (!chip)
-		return -ENODEV;
+	chip = tpmm_chip_alloc(dev, &tpm_vtpm);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
 
 	init_waitqueue_head(&chip->vendor.read_queue);
 
@@ -286,6 +286,7 @@ static int tpmfront_probe(struct xenbus_device *dev,
 		const struct xenbus_device_id *id)
 {
 	struct tpm_private *priv;
+	struct tpm_chip *chip;
 	int rv;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
@@ -302,21 +303,22 @@ static int tpmfront_probe(struct xenbus_device *dev,
 
 	rv = setup_ring(dev, priv);
 	if (rv) {
-		tpm_remove_hardware(&dev->dev);
+		chip = dev_get_drvdata(&dev->dev);
+		tpm_chip_unregister(chip);
 		ring_free(priv);
 		return rv;
 	}
 
 	tpm_get_timeouts(priv->chip);
 
-	return rv;
+	return tpm_chip_register(priv->chip);
 }
 
 static int tpmfront_remove(struct xenbus_device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
 	struct tpm_private *priv = TPM_VPRIV(chip);
-	tpm_remove_hardware(&dev->dev);
+	tpm_chip_unregister(chip);
 	ring_free(priv);
 	TPM_VPRIV(chip) = NULL;
 	return 0;