added prescaler for 16 bit pwm in LPC1347 target
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Diff: targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_K66F/entropy_hardware_poll.c
- Revision:
- 144:ef7eb2e8f9f7
diff -r 423e1876dc07 -r ef7eb2e8f9f7 targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_K66F/entropy_hardware_poll.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_K66F/entropy_hardware_poll.c Fri Sep 02 15:07:44 2016 +0100 @@ -0,0 +1,83 @@ +/* + * Hardware entropy collector for the K66F, using Freescale's RNGA + * + * 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: "K66 Sub-Family Reference Manual, Rev. 2", chapter 38 + */ + +#include <stdlib.h> +#include "cmsis.h" +#include "fsl_common.h" +#include "fsl_clock.h" + +/* + * Get one byte of entropy from the RNG, assuming it is up and running. + * As recommended (34.1.1), get only one bit of each output. + */ +static void rng_get_byte( unsigned char *byte ) +{ + size_t bit; + + /* 34.5 Steps 3-4-5: poll SR and read from OR when ready */ + for( bit = 0; bit < 8; bit++ ) + { + while( ( RNG->SR & RNG_SR_OREG_LVL_MASK ) == 0 ); + *byte |= ( RNG->OR & 1 ) << bit; + } +} + +/* + * Get len bytes of entropy from the hardware RNG. + */ +int mbedtls_hardware_poll( void *data, + unsigned char *output, size_t len, size_t *olen ) +{ + size_t i; + int ret; + ((void) data); + + CLOCK_EnableClock( kCLOCK_Rnga0 ); + CLOCK_DisableClock( kCLOCK_Rnga0 ); + CLOCK_EnableClock( kCLOCK_Rnga0 ); + + /* Set "Interrupt Mask", "High Assurance" and "Go", + * unset "Clear interrupt" and "Sleep" */ + RNG->CR = RNG_CR_INTM_MASK | RNG_CR_HA_MASK | RNG_CR_GO_MASK; + + for( i = 0; i < len; i++ ) + rng_get_byte( output + i ); + + /* Just be extra sure that we didn't do it wrong */ + if( ( RNG->SR & RNG_SR_SECV_MASK ) != 0 ) + { + ret = -1; + goto cleanup; + } + + *olen = len; + ret = 0; + +cleanup: + /* Disable clock to save power - assume we're the only users of RNG */ + CLOCK_DisableClock( kCLOCK_Rnga0 ); + + return( ret ); +} +