tpm: redefine read_log() to handle ACPI/OF at runtime

Currently, read_log() has two implementations: one for ACPI platforms
and the other for device tree(OF) based platforms. The proper one is
selected at compile time using Kconfig and #ifdef in the Makefile,
which is not the recommended approach.

This patch removes the #ifdef in the Makefile by defining a single
read_log() method, which checks for ACPI/OF event log properties at
runtime.

[jarkko.sakkinen@linux.intel.com: added tpm_ prefix to read_log*]

Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/Makefile

@@ -2,16 +2,10 @@
 # Makefile for the kernel tpm device drivers.
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
-tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o
-tpm-$(CONFIG_ACPI) += tpm_ppi.o
-
-ifdef CONFIG_ACPI
-	tpm-y += tpm_eventlog.o tpm_acpi.o
-else
-ifdef CONFIG_TCG_IBMVTPM
-	tpm-y += tpm_eventlog.o tpm_of.o
-endif
-endif
+tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
+		tpm_eventlog.o
+tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
+tpm-$(CONFIG_OF) += tpm_of.o
 obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
 obj-$(CONFIG_TCG_TIS) += tpm_tis.o
 obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi.o

drivers/char/tpm/tpm_acpi.c

@@ -6,6 +6,7 @@
  *	Stefan Berger <stefanb@us.ibm.com>
  *	Reiner Sailer <sailer@watson.ibm.com>
  *	Kylene Hall <kjhall@us.ibm.com>
+ *	Nayna Jain <nayna@linux.vnet.ibm.com>
  *
  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  *
@@ -45,7 +46,7 @@ struct acpi_tcpa {
 };
 
 /* read binary bios log */
-int read_log(struct tpm_chip *chip)
+int tpm_read_log_acpi(struct tpm_chip *chip)
 {
 	struct acpi_tcpa *buff;
 	acpi_status status;
@@ -54,12 +55,6 @@ int read_log(struct tpm_chip *chip)
 	struct tpm_bios_log *log;
 
 	log = &chip->log;
-	if (log->bios_event_log != NULL) {
-		printk(KERN_ERR
-		       "%s: ERROR - Eventlog already initialized\n",
-		       __func__);
-		return -EFAULT;
-	}
 
 	/* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
 	status = acpi_get_table(ACPI_SIG_TCPA, 1,

drivers/char/tpm/tpm_eventlog.c

@@ -356,6 +356,26 @@ static const struct file_operations tpm_bios_measurements_ops = {
 	.release = tpm_bios_measurements_release,
 };
 
+static int tpm_read_log(struct tpm_chip *chip)
+{
+	int rc;
+
+	if (chip->log.bios_event_log != NULL) {
+		dev_dbg(&chip->dev,
+			"%s: ERROR - event log already initialized\n",
+			__func__);
+		return -EFAULT;
+	}
+
+	rc = tpm_read_log_acpi(chip);
+	if ((rc == 0) || (rc == -ENOMEM))
+		return rc;
+
+	rc = tpm_read_log_of(chip);
+
+	return rc;
+}
+
 int tpm_bios_log_setup(struct tpm_chip *chip)
 {
 	const char *name = dev_name(&chip->dev);
@@ -365,7 +385,7 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		return 0;
 
-	rc = read_log(chip);
+	rc = tpm_read_log(chip);
 	/*
 	 * read_log failure means event log is not supported except for ENOMEM.
 	 */

drivers/char/tpm/tpm_eventlog.h

@@ -73,20 +73,24 @@ enum tcpa_pc_event_ids {
 	HOST_TABLE_OF_DEVICES,
 };
 
-int read_log(struct tpm_chip *chip);
-
-#if defined(CONFIG_TCG_IBMVTPM) || defined(CONFIG_TCG_IBMVTPM_MODULE) || \
-	defined(CONFIG_ACPI)
-extern int tpm_bios_log_setup(struct tpm_chip *chip);
-extern void tpm_bios_log_teardown(struct tpm_chip *chip);
+#if defined(CONFIG_ACPI)
+int tpm_read_log_acpi(struct tpm_chip *chip);
 #else
-static inline int tpm_bios_log_setup(struct tpm_chip *chip)
+static inline int tpm_read_log_acpi(struct tpm_chip *chip)
 {
-	return 0;
+	return -ENODEV;
 }
-static inline void tpm_bios_log_teardown(struct tpm_chip *chip)
+#endif
+#if defined(CONFIG_OF)
+int tpm_read_log_of(struct tpm_chip *chip);
+#else
+static inline int tpm_read_log_of(struct tpm_chip *chip)
 {
+	return -ENODEV;
 }
 #endif
 
+int tpm_bios_log_setup(struct tpm_chip *chip);
+void tpm_bios_log_teardown(struct tpm_chip *chip);
+
 #endif

drivers/char/tpm/tpm_of.c

@@ -2,6 +2,7 @@
  * Copyright 2012 IBM Corporation
  *
  * Author: Ashley Lai <ashleydlai@gmail.com>
+ *         Nayna Jain <nayna@linux.vnet.ibm.com>
  *
  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  *
@@ -20,19 +21,14 @@
 #include "tpm.h"
 #include "tpm_eventlog.h"
 
-int read_log(struct tpm_chip *chip)
+int tpm_read_log_of(struct tpm_chip *chip)
 {
 	struct device_node *np;
 	const u32 *sizep;
 	const u64 *basep;
 	struct tpm_bios_log *log;
 
 	log = &chip->log;
-	if (log->bios_event_log != NULL) {
-		pr_err("%s: ERROR - Eventlog already initialized\n", __func__);
-		return -EFAULT;
-	}
-
 	np = of_find_node_by_name(NULL, "vtpm");
 	if (!np) {
 		pr_err("%s: ERROR - IBMVTPM not supported\n", __func__);