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 <stef...@linux.ibm.com>
Cc: Jarkko Sakkinen <jar...@kernel.org>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Rob Herring <robh...@kernel.org>
Cc: Frank Rowand <frowand.l...@gmail.com>
Reviewed-by: Mimi Zohar <zo...@linux.ibm.com>
Tested-by: Nageswara R Sastry <rnsas...@linux.ibm.com>
Tested-by: Coiby Xu <c...@redhat.com>
Acked-by: Jarkko Sakkinen <jar...@kernel.org>

---
v9:
 - Rebased on 6.3-rc7; call tpm_read_log_memory_region if -ENODEV returned

v7:
 - Added original comment back into inlined function

v4:
 - converted to inline function
---
 drivers/char/tpm/eventlog/of.c | 30 +++++-----------------------
 include/linux/tpm.h            | 36 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 25 deletions(-)

diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
index 930fe43d5daf..41688d9cbd3b 100644
--- a/drivers/char/tpm/eventlog/of.c
+++ b/drivers/char/tpm/eventlog/of.c
@@ -51,11 +51,10 @@ static int tpm_read_log_memory_region(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;
        u32 size;
        u64 base;
+       int ret;
 
        log = &chip->log;
        if (chip->dev.parent && chip->dev.parent->of_node)
@@ -66,30 +65,11 @@ 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)
+       ret = of_tpm_get_sml_parameters(np, &base, &size);
+       if (ret == -ENODEV)
                return tpm_read_log_memory_region(chip);
-       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;
-       }
+       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 4dc97b9f65fb..dd9a376a1dbb 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -461,4 +461,40 @@ 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
-- 
2.38.1

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