Rename the platform context varaiable

Rename the generic name `ctx` of `mbedtls_platform_context`
in `platform_alt.c` to a specific name `plat_ctx`, to avoid conflicts
when used as external in crypto modules.

Author: Ron Eldor

features/cryptocell/FEATURE_CRYPTOCELL310/trng.c

@@ -24,7 +24,7 @@
 #include "trng_api.h"
 #include "mbedtls/platform.h"
 
-extern mbedtls_platform_context  ctx;
+extern mbedtls_platform_context  plat_ctx;
 static CRYS_RND_WorkBuff_t  rndWorkBuff = { { 0 } };
 
 /* Implementation that should never be optimized out by the compiler */
@@ -49,7 +49,7 @@ CRYSError_t LLF_RND_GetTrngSource(
 
 void trng_init(trng_t *obj)
 {
-    RNG_PLAT_SetUserRngParameters(&ctx.platform_impl_ctx.rndState, obj);
+    RNG_PLAT_SetUserRngParameters(&plat_ctx.platform_impl_ctx.rndState, obj);
 }
 
 void trng_free(trng_t *obj)
@@ -67,7 +67,7 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *outputLe
     uint32_t actualLength;
 
     ret = LLF_RND_GetTrngSource(
-                &ctx.platform_impl_ctx.rndState ,    /*in/out*/
+                &plat_ctx.platform_impl_ctx.rndState ,    /*in/out*/
                 obj,       /*in/out*/
                 0,       /*in*/
                 &entropySizeBits,  /*in/out*/

features/mbedtls/platform/src/platform_alt.c

@@ -22,30 +22,30 @@
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
 #include "mbed_critical.h"
 
-mbedtls_platform_context ctx = { { 0 } };
+mbedtls_platform_context plat_ctx = { { 0 } };
 
 int mbedtls_platform_setup( mbedtls_platform_context *unused_ctx )
 {
     int ret = 0;
 
-    core_util_atomic_incr_u32( ( volatile uint32_t * )&ctx.reference_count, 1 );
+    core_util_atomic_incr_u32( ( volatile uint32_t * )&plat_ctx.reference_count, 1 );
 
-    if( ctx.reference_count == 1 )
+    if( plat_ctx.reference_count == 1 )
     {
         /* call platform specific code to setup crypto driver */
-        ret = crypto_platform_setup( &ctx.platform_impl_ctx );
+        ret = crypto_platform_setup( &plat_ctx.platform_impl_ctx );
     }
     return ( ret );
 }
 
 void mbedtls_platform_teardown( mbedtls_platform_context *unused_ctx )
 {
-    core_util_atomic_decr_u32( ( volatile uint32_t * )&ctx.reference_count, 1 );
-    if( ctx.reference_count < 1 )
+    core_util_atomic_decr_u32( ( volatile uint32_t * )&plat_ctx.reference_count, 1 );
+    if( plat_ctx.reference_count < 1 )
     {
         /* call platform specific code to terminate crypto driver */
-        crypto_platform_terminate( &ctx.platform_impl_ctx );
-        ctx.reference_count = 0;
+        crypto_platform_terminate( &plat_ctx.platform_impl_ctx );
+        plat_ctx.reference_count = 0;
     }
 }