[PATCH v7 4/6] tpm: of: Make of-tree specific function commonly available

Stefan Berger
2022-08-12T17:06:30Z

Simplify tpm_read_log_of() by moving reusable parts of the code into
an inline function that makes it commonly available so it can be
used also for kexec support. Call the new of_tpm_get_sml_parameters()
function from the TPM Open Firmware driver.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>

---
v7:
- Added original comment back into inlined function

v4:
- converted to inline function
---
drivers/char/tpm/eventlog/of.c | 31 +++++------------------------
include/linux/tpm.h | 36 ++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
index a9ce66d09a75..f9462d19632e 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/tpm.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/include/linux/tpm.h b/include/linux/tpm.h
index dfeb25a0362d..6356baaa1393 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -460,4 +460,40 @@ static inline struct tpm_chip *tpm_default_chip(void)
return NULL;
}
#endif
+
+#ifdef CONFIG_OF
+static inline 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;
+
+ /*
+ * 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;
+ }
+ return 0;
+}
+#endif
+
#endif
--
2.35.1