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drivers/serial: Add 16550_DLF_SIZE option for DesignWare UART.

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Signed-off-by: sunjikun <sunjikun@xiaomi.com>
This commit is contained in:
sunjikun 2023-10-25 17:20:51 +08:00 • committed by Xiang Xiao
parent c00d477671
commit ee306d47fd
3 changed files with 51 additions and 17 deletions
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7
drivers/serial/Kconfig-16550
View file

@ -554,4 +554,11 @@ config 16550_SET_MCR_OUT2
---help---
Some platforms require OUT2 of MCR being set for interrupt to be triggered
config 16550_DLF_SIZE
int "DLF(Divisor Latch Fraction) size of DesignWare APB UART"
default 0
---help---
The bit width of DLF register for DesignWare APB UART.
DLF_SIZE=0 means no support. Default: 0
endif # 16550_UART

18
drivers/serial/uart_16550.c
View file

@ -760,7 +760,16 @@ static inline void u16550_enablebreaks(FAR struct u16550_s *priv,
#ifndef CONFIG_16550_SUPRESS_CONFIG
static inline uint32_t u16550_divisor(FAR struct u16550_s *priv)
{
return (priv->uartclk + (priv->baud << 3)) / (priv->baud << 4);
uint32_t base = 16 * priv->baud;
uint32_t quot = priv->uartclk / base;
uint32_t rem = priv->uartclk % base;
uint32_t frac = ((rem << CONFIG_16550_DLF_SIZE) + base / 2) / base;
#if CONFIG_16550_DLF_SIZE != 0
return quot | (frac << 16);
#else
return quot + frac;
#endif
}
#endif
@ -778,7 +787,7 @@ static int u16550_setup(FAR struct uart_dev_s *dev)
{
#ifndef CONFIG_16550_SUPRESS_CONFIG
FAR struct u16550_s *priv = (FAR struct u16550_s *)dev->priv;
uint16_t div;
uint32_t div;
uint32_t lcr;
#if defined(CONFIG_SERIAL_IFLOWCONTROL) || defined(CONFIG_SERIAL_OFLOWCONTROL) || \
defined(CONFIG_16550_SET_MCR_OUT2)
@ -855,7 +864,10 @@ static int u16550_setup(FAR struct uart_dev_s *dev)
/* Set the BAUD divisor */
div = u16550_divisor(priv);
u16550_serialout(priv, UART_DLM_OFFSET, div >> 8);
#if CONFIG_16550_DLF_SIZE != 0
u16550_serialout(priv, UART_DLF_OFFSET, (div >> 16) & 0xff);
#endif
u16550_serialout(priv, UART_DLM_OFFSET, (div >> 8) & 0xff);
u16550_serialout(priv, UART_DLL_OFFSET, div & 0xff);
#ifdef CONFIG_16550_WAIT_LCR

43
include/nuttx/serial/uart_16550.h
View file

@ -173,20 +173,35 @@
/* Register offsets *********************************************************/
#define UART_RBR_OFFSET 0 /* (DLAB =0) Receiver Buffer Register */
#define UART_THR_OFFSET 0 /* (DLAB =0) Transmit Holding Register */
#define UART_DLL_OFFSET 0 /* (DLAB =1) Divisor Latch LSB */
#define UART_DLM_OFFSET 1 /* (DLAB =1) Divisor Latch MSB */
#define UART_IER_OFFSET 1 /* (DLAB =0) Interrupt Enable Register */
#define UART_IIR_OFFSET 2 /* Interrupt ID Register */
#define UART_FCR_OFFSET 2 /* FIFO Control Register */
#define UART_LCR_OFFSET 3 /* Line Control Register */
#define UART_MCR_OFFSET 4 /* Modem Control Register */
#define UART_LSR_OFFSET 5 /* Line Status Register */
#define UART_MSR_OFFSET 6 /* Modem Status Register */
#define UART_SCR_OFFSET 7 /* Scratch Pad Register */
#define UART_USR_OFFSET 31 /* UART Status Register */
#define UART_DLF_OFFSET 48 /* Divisor Latch Fraction Register */
#define UART_RBR_INCR 0 /* (DLAB =0) Receiver Buffer Register */
#define UART_THR_INCR 0 /* (DLAB =0) Transmit Holding Register */
#define UART_DLL_INCR 0 /* (DLAB =1) Divisor Latch LSB */
#define UART_DLM_INCR 1 /* (DLAB =1) Divisor Latch MSB */
#define UART_IER_INCR 1 /* (DLAB =0) Interrupt Enable Register */
#define UART_IIR_INCR 2 /* Interrupt ID Register */
#define UART_FCR_INCR 2 /* FIFO Control Register */
#define UART_LCR_INCR 3 /* Line Control Register */
#define UART_MCR_INCR 4 /* Modem Control Register */
#define UART_LSR_INCR 5 /* Line Status Register */
#define UART_MSR_INCR 6 /* Modem Status Register */
#define UART_SCR_INCR 7 /* Scratch Pad Register */
#define UART_USR_INCR 31 /* UART Status Register */
#define UART_DLF_INCR 48 /* Divisor Latch Fraction Register */
#define UART_RBR_OFFSET (CONFIG_16550_REGINCR*UART_RBR_INCR)
#define UART_THR_OFFSET (CONFIG_16550_REGINCR*UART_THR_INCR)
#define UART_DLL_OFFSET (CONFIG_16550_REGINCR*UART_DLL_INCR)
#define UART_DLM_OFFSET (CONFIG_16550_REGINCR*UART_DLM_INCR)
#define UART_IER_OFFSET (CONFIG_16550_REGINCR*UART_IER_INCR)
#define UART_IIR_OFFSET (CONFIG_16550_REGINCR*UART_IIR_INCR)
#define UART_FCR_OFFSET (CONFIG_16550_REGINCR*UART_FCR_INCR)
#define UART_LCR_OFFSET (CONFIG_16550_REGINCR*UART_LCR_INCR)
#define UART_MCR_OFFSET (CONFIG_16550_REGINCR*UART_MCR_INCR)
#define UART_LSR_OFFSET (CONFIG_16550_REGINCR*UART_LSR_INCR)
#define UART_MSR_OFFSET (CONFIG_16550_REGINCR*UART_MSR_INCR)
#define UART_SCR_OFFSET (CONFIG_16550_REGINCR*UART_SCR_INCR)
#define UART_USR_OFFSET (CONFIG_16550_REGINCR*UART_USR_INCR)
#define UART_DLF_OFFSET (CONFIG_16550_REGINCR*UART_DLF_INCR)
/* Register bit definitions *************************************************/