Re: [PATCH v5 4/6] tpm: of: Make of-tree specific function commonly available

On 7/10/22 23:04, Jarkko Sakkinen wrote:

On Wed, Jul 06, 2022 at 11:23:27AM -0400, Stefan Berger wrote:

quoted

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 <redacted>

---
v4:
  - converted to inline function
---
  drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
  include/linux/tpm.h            | 27 +++++++++++++++++++++++++++
  2 files changed, 32 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.
-	 */

Jarkko,

  can I apply your R-b tag after putting this lost comment back into the 
inline function?
    Stefan

quoted

-	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..b3dff255bc58 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h

@@ -460,4 +460,31 @@ 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;
+
+	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

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko

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