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cpu/nrf52840: fix UART DMA when data is in ROM

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This commit is contained in:
Hauke Petersen 2019-03-13 13:00:42 +01:00
parent 297efdd5b2
commit 91057de140
1 changed files with 34 additions and 4 deletions
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38
cpu/nrf5x_common/periph/uart.c
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@ -27,6 +27,7 @@
*/
#include <stdint.h>
#include <string.h>
#include "cpu.h"
#include "periph/uart.h"
@ -46,6 +47,14 @@
#define UART_HWFLOWCTRL (uart_config[uart].rts_pin != (uint8_t)GPIO_UNDEF && \
uart_config[uart].cts_pin != (uint8_t)GPIO_UNDEF)
#define ISR_CTX isr_ctx[uart]
#define RAM_MASK (0x20000000)
/**
* @brief Chunk size used for transferring data from ROM [in bytes]
*/
#ifndef NRF_UARTE_CHUNK_SIZE
#define NRF_UARTE_CHUNK_SIZE (32U)
#endif
/**
* @brief Allocate memory for the interrupt context
@ -213,11 +222,8 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
#ifdef CPU_MODEL_NRF52840XXAA /* nrf52840 (using EasyDMA) */
void uart_write(uart_t uart, const uint8_t *data, size_t len)
static void _write_buf(uart_t uart, const uint8_t *data, size_t len)
{
assert(uart < UART_NUMOF);
/* reset endtx flag */
dev(uart)->EVENTS_ENDTX = 0;
/* set data to transfer to DMA TX pointer */
@ -229,6 +235,30 @@ void uart_write(uart_t uart, const uint8_t *data, size_t len)
while (dev(uart)->EVENTS_ENDTX == 0) {}
}
void uart_write(uart_t uart, const uint8_t *data, size_t len)
{
assert(uart < UART_NUMOF);
/* EasyDMA can only transfer data from RAM (see ref. manual, sec. 6.34.1).
* So if the given `data` buffer resides in ROM, we need to copy it to RAM
* before being able to transfer it. To make sure the stack does not
* overflow, we do this chunk-wise. */
if (!((uint32_t)data & RAM_MASK)) {
size_t pos = 0;
while (pos < len) {
uint8_t tmp[NRF_UARTE_CHUNK_SIZE];
size_t off = len - pos;
off = (off > NRF_UARTE_CHUNK_SIZE) ? NRF_UARTE_CHUNK_SIZE : off;
memcpy(tmp, data + pos, off);
_write_buf(uart, tmp, off);
pos += off;
}
}
else {
_write_buf(uart, data, len);
}
}
void uart_poweron(uart_t uart)
{
assert(uart < UART_NUMOF);