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arch/arm/src/imxrt/imxrt_lowputc.c: This commit removes a largely redundant check in the imxrt lowputc code which will speed it up a little.

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I did suspect that it was just about possible that there's a use for this check (specifically, when you're changing serial the clock immediately after the character is sent) but since we're only testing that the character has left the holding register and not that it's actually been sent to line I don't think it's valid even for this case.
This commit is contained in:
Dave Marples 2019-11-26 17:45:23 -06:00 committed by Gregory Nutt
parent 7f56da62f1
commit c2211d8d3c
1 changed files with 11 additions and 14 deletions
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25
arch/arm/src/imxrt/imxrt_lowputc.c
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@ -393,6 +393,7 @@ int imxrt_lpuart_configure(uint32_t base,
uint32_t calculated_baud;
uint32_t baud_diff;
uint32_t regval;
uint32_t regval2;
if ((getreg32(IMXRT_CCM_CSCDR1) & CCM_CSCDR1_UART_CLK_SEL) != 0)
{
@ -413,7 +414,8 @@ int imxrt_lpuart_configure(uint32_t base,
src_freq = (BOARD_XTAL_FREQUENCY * pll3_div) / 6;
}
uart_div = (getreg32(IMXRT_CCM_CSCDR1) & CCM_CSCDR1_UART_CLK_PODF_MASK) + 1;
uart_div = (getreg32(IMXRT_CCM_CSCDR1) &
CCM_CSCDR1_UART_CLK_PODF_MASK) + 1;
lpuart_freq = src_freq / uart_div;
/* This LPUART instantiation uses a slightly different baud rate
@ -451,9 +453,11 @@ int imxrt_lpuart_configure(uint32_t base,
/* Select the better value between srb and (sbr + 1) */
if (temp_diff > (config->baud - (lpuart_freq / (temp_osr * (temp_sbr + 1)))))
if (temp_diff > (config->baud -
(lpuart_freq / (temp_osr * (temp_sbr + 1)))))
{
temp_diff = config->baud - (lpuart_freq / (temp_osr * (temp_sbr + 1)));
temp_diff = config->baud -
(lpuart_freq / (temp_osr * (temp_sbr + 1)));
temp_sbr++;
}
@ -556,8 +560,10 @@ int imxrt_lpuart_configure(uint32_t base,
return ERROR;
}
putreg32(LPUART_FIFO_RXFE | LPUART_FIFO_RXIDEN_1 | LPUART_FIFO_TXFE ,
base + IMXRT_LPUART_FIFO_OFFSET);
regval2 = getreg32(base + IMXRT_LPUART_FIFO_OFFSET);
regval2 |= LPUART_FIFO_RXFLUSH | LPUART_FIFO_TXFLUSH |
LPUART_FIFO_RXFE | LPUART_FIFO_RXIDEN_1 | LPUART_FIFO_TXFE;
putreg32(regval2 , base + IMXRT_LPUART_FIFO_OFFSET);
regval |= LPUART_CTRL_RE | LPUART_CTRL_TE;
putreg32(regval, base + IMXRT_LPUART_CTRL_OFFSET);
@ -605,14 +611,5 @@ void imxrt_lowputc(int ch)
/* Send the character by writing it into the UART_TXD register. */
putreg32((uint32_t)ch, IMXRT_CONSOLE_BASE + IMXRT_LPUART_DATA_OFFSET);
/* Wait for the transmit register to be emptied. When the TXFE bit is
* non-zero, the TX Buffer FIFO is empty.
*/
while ((getreg32(IMXRT_CONSOLE_BASE + IMXRT_LPUART_STAT_OFFSET) &
LPUART_STAT_TDRE) == 0)
{
}
}
#endif