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Add TRNG support for KW41Z #4050

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Mar 29, 2017
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Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
/*
* Hardware entropy collector for the K64F, using Freescale's RNGA
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The target name seems to be incorrect on this line

*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/

/*
* Reference: "K64 Sub-Family Reference Manual, Rev. 2", chapter 34
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This reference is misleading here, it would be very helpful to have the right document here.

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Thank you. I have fixed this.

*/

#if defined(DEVICE_TRNG)

#include "fsl_trng.h"
#include "trng_api.h"

void trng_init(trng_t *obj)
{
trng_config_t trngConfig;

TRNG_GetDefaultConfig(&trngConfig);
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According to the manual this function can return with an error. Because of the API we can't propagate this error, but we still need to make it sure that if an error has happened here then any subsequent calls to trng_get_bytes() will fail with an error.

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The error returned is in case the user passes an invalid argument (invalid uage of this API). This will not happen in mbed HAL.

/* Set sample mode of the TRNG ring oscillator to Von Neumann, for better random data.*/
trngConfig.sampleMode = kTRNG_SampleModeVonNeumann;
/* Initialize TRNG */
TRNG_Init(TRNG0, &trngConfig);
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According to the manual this function can return with an error. Because of the API we can't propagate this error, but we still need to make it sure that if an error has happened here then any subsequent calls to trng_get_bytes() will fail with an error.

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The error returned is in case the user passes an invalid argument (invalid uage of this API). This will not happen in mbed HAL.

}

void trng_free(trng_t *obj)
{
TRNG_Deinit(TRNG0);
}

int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
{
status_t result;

result = TRNG_GetRandomData(TRNG0, output, length);

if (result == kStatus_Success) {
*output_length = length;
return 0;
} else {
return -1;
}
}

#endif
2 changes: 1 addition & 1 deletion targets/targets.json
Original file line number Diff line number Diff line change
Expand Up @@ -567,7 +567,7 @@
"macros": ["CPU_MKW41Z512VHT4", "FSL_RTOS_MBED"],
"inherits": ["Target"],
"detect_code": ["0201"],
"device_has": ["ANALOGIN", "ANALOGOUT", "ERROR_RED", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SLEEP", "SPI", "SPISLAVE", "STDIO_MESSAGES"],
"device_has": ["ANALOGIN", "ANALOGOUT", "ERROR_RED", "I2C", "I2CSLAVE", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "RTC", "SERIAL", "SLEEP", "SPI", "SPISLAVE", "TRNG", "STDIO_MESSAGES"],
"release_versions": ["2", "5"],
"device_name": "MKW41Z512xxx4"
},
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