mbedtls_config: fix descriptions for PSA static key slots
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 7272897..8d2afbf 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -3271,15 +3271,17 @@
/**
* \def MBEDTLS_PSA_STATIC_KEY_SLOTS
*
- * Statically preallocate all key slot buffers to store volatile keys in PSA
- * instead of allocating them dynamically when required. This helps reducing
- * heap memory usage as well as heap management code's footprint in embedded
- * devices.
+ * Statically preallocate memory to store keys' material in PSA instead
+ * of allocating it dynamically when required. This allows builds without a
+ * heap, if none of the enabled cryptographic implementations or other features
+ * require it.
+ * This feature affects both volatile and persistent keys which means that
+ * it's not possible to persistently store a key which is larger than
+ * MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE.
*
* \note This feature comes with a (potentially) higher RAM usage since:
* - All the key slots are allocated no matter if they are used of not.
- * - Each key slot's length is as large as the largest key type supported
- * in the build.
+ * - Each key buffer's length is MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE bytes.
*
* Requires: MBEDTLS_PSA_CRYPTO_C
*
@@ -4088,17 +4090,15 @@
//#define MBEDTLS_PSA_KEY_SLOT_COUNT 32
/**
- * \def MBEDTLS_PSA_STATIC_KEY_SLOTS
+ * \def MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE
*
- * Optionally define the size (in bytes) of each static key slot. If not
+ * Define the size (in bytes) of each static key slot when
+ * MBEDTLS_PSA_STATIC_KEY_SLOTS is set. If not
* explicitly defined then it's automatically set to hold the maximum
* asymmetric PSA key enabled in the build (through PSA_WANT_xxx symbols).
* If required by the application this parameter can be set to higher values
* in order to store larger objects (ex: raw keys), but please note that this
* will increase RAM usage.
- *
- * Requires: MBEDTLS_PSA_STATIC_KEY_SLOTS
- *
*/
//#define MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE 256