[PATCH v2 1/3] tpm: of: Move of-tree specific code from tpm driver into of driver

[Stefan Berger]

Simplify tpm_read_log_of() by moving Openfirmware-specific code into
the Openfirmware driver to make the code reusable. Call the new
of_tpm_get_sml_parameters() function from the TPM Openfirmware driver.

Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
Cc: Jarkko Sakkinen <jarkko at kernel.org>
Cc: Jason Gunthorpe <jgg at ziepe.ca>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Frank Rowand <frowand.list at gmail.com>
---
 drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
 drivers/of/Makefile            |  2 +-
 drivers/of/device_node.c       | 27 +++++++++++++++++++++++++++
 include/linux/of_device_node.h |  9 +++++++++
 4 files changed, 42 insertions(+), 27 deletions(-)
 create mode 100644 drivers/of/device_node.c
 create mode 100644 include/linux/of_device_node.h

diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
index a9ce66d09a75..5b18f4333ad1 100644
--- a/drivers/char/tpm/eventlog/of.c
+++ b/drivers/char/tpm/eventlog/of.c
@@ -12,6 +12,7 @@
 
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/of_device_node.h>
 #include <linux/tpm_eventlog.h>
 
 #include "../tpm.h"
@@ -20,11 +21,10 @@
 int tpm_read_log_of(struct tpm_chip *chip)
 {
 	struct device_node *np;
-	const u32 *sizep;
-	const u64 *basep;
 	struct tpm_bios_log *log;
 	u32 size;
 	u64 base;
+	int ret;
 
 	log = &chip->log;
 	if (chip->dev.parent && chip->dev.parent->of_node)
@@ -35,30 +35,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	if (of_property_read_bool(np, "powered-while-suspended"))
 		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
 
-	sizep = of_get_property(np, "linux,sml-size", NULL);
-	basep = of_get_property(np, "linux,sml-base", NULL);
-	if (sizep == NULL && basep == NULL)
-		return -ENODEV;
-	if (sizep == NULL || basep == NULL)
-		return -EIO;
-
-	/*
-	 * For both vtpm/tpm, firmware has log addr and log size in big
-	 * endian format. But in case of vtpm, there is a method called
-	 * sml-handover which is run during kernel init even before
-	 * device tree is setup. This sml-handover function takes care
-	 * of endianness and writes to sml-base and sml-size in little
-	 * endian format. For this reason, vtpm doesn't need conversion
-	 * but physical tpm needs the conversion.
-	 */
-	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
-	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
-		size = be32_to_cpup((__force __be32 *)sizep);
-		base = be64_to_cpup((__force __be64 *)basep);
-	} else {
-		size = *sizep;
-		base = *basep;
-	}
+	ret = of_tpm_get_sml_parameters(np, &base, &size);
+	if (ret < 0)
+		return ret;
 
 	if (size == 0) {
 		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index e0360a44306e..1c9feac450ad 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-y = base.o device.o platform.o property.o
+obj-y = base.o device.o platform.o property.o device_node.o
 obj-$(CONFIG_OF_KOBJ) += kobj.o
 obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
 obj-$(CONFIG_OF_FLATTREE) += fdt.o
diff --git a/drivers/of/device_node.c b/drivers/of/device_node.c
new file mode 100644
index 000000000000..71a19bc1bac2
--- /dev/null
+++ b/drivers/of/device_node.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/export.h>
+#include <linux/of_device_node.h>
+
+int of_tpm_get_sml_parameters(struct device_node *np, u64 *base, u32 *size)
+{
+	const u32 *sizep;
+	const u64 *basep;
+
+	sizep = of_get_property(np, "linux,sml-size", NULL);
+	basep = of_get_property(np, "linux,sml-base", NULL);
+	if (sizep == NULL && basep == NULL)
+		return -ENODEV;
+	if (sizep == NULL || basep == NULL)
+		return -EIO;
+
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
+	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
+		*size = be32_to_cpup((__force __be32 *)sizep);
+		*base = be64_to_cpup((__force __be64 *)basep);
+	} else {
+		*size = *sizep;
+		*base = *basep;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_tpm_get_sml_parameters);
diff --git a/include/linux/of_device_node.h b/include/linux/of_device_node.h
new file mode 100644
index 000000000000..ae3faf023aab
--- /dev/null
+++ b/include/linux/of_device_node.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_OF_DEVICE_NODE_H
+#define _LINUX_OF_DEVICE_NODE_H
+
+#include <linux/of.h>
+
+int of_tpm_get_sml_parameters(struct device_node *np, u64 *base, u32 *size);
+
+#endif /* _LINUX_OF_DEVICE_NODE_H */
-- 
2.35.1