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https://github.com/zephyrproject-rtos/zephyr
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75f77db432
There are issues using lowercase min and max macros when compiling a C++ application with a third-party toolchain such as GNU ARM Embedded when using some STL headers i.e. <chrono>. This is because there are actual C++ functions called min and max defined in some of the STL headers and these macros interfere with them. By changing the macros to UPPERCASE, which is consistent with almost all other pre-processor macros this naming conflict is avoided. All files that use these macros have been updated. Signed-off-by: Carlos Stuart <carlosstuart1970@gmail.com>
96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
/*
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* Copyright (c) 2018 Aurelien Jarno
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <device.h>
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#include <entropy.h>
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#include <errno.h>
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#include <init.h>
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#include <soc.h>
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#include <string.h>
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struct trng_sam_dev_cfg {
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Trng *regs;
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};
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#define DEV_CFG(dev) \
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((const struct trng_sam_dev_cfg *const)(dev)->config->config_info)
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static int entropy_sam_wait_ready(Trng *const trng)
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{
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/* According to the reference manual, the generator provides
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* one 32-bit random value every 84 peripheral clock cycles.
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* MCK may not be smaller than HCLK/4, so it should not take
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* more than 336 HCLK ticks. Assuming the CPU can do 1
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* instruction per HCLK the number of times to loop before
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* the TRNG is ready is less than 1000. And that is when
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* assuming the loop only takes 1 instruction. So looping a
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* million times should be more than enough.
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*/
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int timeout = 1000000;
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while (!(trng->TRNG_ISR & TRNG_ISR_DATRDY)) {
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if (timeout-- == 0) {
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return -ETIMEDOUT;
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}
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k_yield();
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}
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return 0;
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}
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static int entropy_sam_get_entropy(struct device *dev, u8_t *buffer,
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u16_t length)
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{
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Trng *const trng = DEV_CFG(dev)->regs;
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while (length > 0) {
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size_t to_copy;
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u32_t value;
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int res;
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res = entropy_sam_wait_ready(trng);
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if (res < 0) {
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return res;
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}
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value = trng->TRNG_ODATA;
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to_copy = MIN(length, sizeof(value));
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memcpy(buffer, &value, to_copy);
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buffer += to_copy;
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length -= to_copy;
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}
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return 0;
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}
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static int entropy_sam_init(struct device *dev)
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{
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Trng *const trng = DEV_CFG(dev)->regs;
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/* Enable the user interface clock */
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soc_pmc_peripheral_enable(DT_ENTROPY_SAM_TRNG_PERIPHERAL_ID);
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/* Enable the TRNG */
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trng->TRNG_CR = TRNG_CR_KEY_PASSWD | TRNG_CR_ENABLE;
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return 0;
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}
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static const struct entropy_driver_api entropy_sam_api = {
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.get_entropy = entropy_sam_get_entropy
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};
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static const struct trng_sam_dev_cfg trng_sam_cfg = {
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.regs = (Trng *)DT_ENTROPY_SAM_TRNG_BASE_ADDRESS,
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};
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DEVICE_AND_API_INIT(entropy_sam, CONFIG_ENTROPY_NAME,
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entropy_sam_init, NULL, &trng_sam_cfg,
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PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
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&entropy_sam_api);
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