This improves the performance of U-Boot when accepting rapid input, such as pasting a sequence of commands.
Without this patch, on P4080DS I see a maximum of around 5 mw.l lines can be pasted. With this patch, it handles around 70 lines before lossage, long enough for most things you'd paste.
Signed-off-by: Scott Wood scottwood@freescale.com --- README | 8 ++++ drivers/serial/ns16550.c | 96 +++++++++++++++++++++++++++++++++++++++++++-- drivers/serial/serial.c | 4 +- include/ns16550.h | 4 +- 4 files changed, 103 insertions(+), 9 deletions(-)
diff --git a/README b/README index bd03523..d21ea9c 100644 --- a/README +++ b/README @@ -2682,6 +2682,14 @@ use the "saveenv" command to store a valid environment. space for already greatly restricted images, including but not limited to NAND_SPL configurations.
+- CONFIG_NS16550_BUFFER_READS: + Instead of reading directly from the receive register + every time U-Boot is ready for another byte, keep a + buffer and fill it from the hardware fifo every time + U-Boot reads a character. This helps U-Boot keep up with + a larger amount of rapid input, such as happens when + pasting text into the terminal. + Low Level (hardware related) configuration options: ---------------------------------------------------
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c index 8eeb48f..ed3428d 100644 --- a/drivers/serial/ns16550.c +++ b/drivers/serial/ns16550.c @@ -4,12 +4,15 @@ * modified to use CONFIG_SYS_ISA_MEM and new defines */
+#include <common.h> #include <config.h> #include <ns16550.h> #include <watchdog.h> #include <linux/types.h> #include <asm/io.h>
+DECLARE_GLOBAL_DATA_PTR; + #define UART_LCRVAL UART_LCR_8N1 /* 8 data, 1 stop, no parity */ #define UART_MCRVAL (UART_MCR_DTR | \ UART_MCR_RTS) /* RTS/DTR */ @@ -86,21 +89,104 @@ void NS16550_putc (NS16550_t com_port, char c) }
#ifndef CONFIG_NS16550_MIN_FUNCTIONS -char NS16550_getc (NS16550_t com_port) + +static char NS16550_raw_getc(NS16550_t regs) { - while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) { + while ((serial_in(®s->lsr) & UART_LSR_DR) == 0) { #ifdef CONFIG_USB_TTY extern void usbtty_poll(void); usbtty_poll(); #endif WATCHDOG_RESET(); } - return serial_in(&com_port->rbr); + return serial_in(®s->rbr); +} + +static int NS16550_raw_tstc(NS16550_t regs) +{ + return ((serial_in(®s->lsr) & UART_LSR_DR) != 0); +} + + +#ifdef CONFIG_NS16550_BUFFER_READS + +#define BUF_SIZE 256 +#define NUM_PORTS 4 + +struct ns16550_priv { + char buf[BUF_SIZE]; + unsigned int head, tail; +}; + +static struct ns16550_priv rxstate[NUM_PORTS]; + +static void enqueue(unsigned int port, char ch) +{ + /* If queue is full, drop the character. */ + if ((rxstate[port].head - rxstate[port].tail - 1) % BUF_SIZE == 0) + return; + + rxstate[port].buf[rxstate[port].tail] = ch; + rxstate[port].tail = (rxstate[port].tail + 1) % BUF_SIZE; +} + +static int dequeue(unsigned int port, char *ch) +{ + /* Empty queue? */ + if (rxstate[port].head == rxstate[port].tail) + return 0; + + *ch = rxstate[port].buf[rxstate[port].head]; + rxstate[port].head = (rxstate[port].head + 1) % BUF_SIZE; + return 1; +} + +static void fill_rx_buf(NS16550_t regs, unsigned int port) +{ + while ((serial_in(®s->lsr) & UART_LSR_DR) != 0) + enqueue(port, serial_in(®s->rbr)); +} + +char NS16550_getc(NS16550_t regs, unsigned int port) +{ + char ch; + + if (port >= NUM_PORTS || !(gd->flags & GD_FLG_RELOC)) + return NS16550_raw_getc(regs); + + do { +#ifdef CONFIG_USB_TTY + extern void usbtty_poll(void); + usbtty_poll(); +#endif + fill_rx_buf(regs, port); + WATCHDOG_RESET(); + } while (!dequeue(port, &ch)); + + return ch; +} + +int NS16550_tstc(NS16550_t regs, unsigned int port) +{ + if (port >= NUM_PORTS || !(gd->flags & GD_FLG_RELOC)) + return NS16550_raw_tstc(regs); + + fill_rx_buf(regs, port); + + return rxstate[port].head != rxstate[port].tail; +} + +#else /* CONFIG_NS16550_BUFFER_READS */ + +char NS16550_getc(NS16550_t regs, unsigned int port) +{ + return NS16550_raw_getc(regs); }
-int NS16550_tstc (NS16550_t com_port) +int NS16550_tstc(NS16550_t regs, unsigned int port) { - return ((serial_in(&com_port->lsr) & UART_LSR_DR) != 0); + return NS16550_raw_tstc(regs); }
+#endif /* CONFIG_NS16550_BUFFER_READS */ #endif /* CONFIG_NS16550_MIN_FUNCTIONS */ diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c index 4032dfd..3fc80b1 100644 --- a/drivers/serial/serial.c +++ b/drivers/serial/serial.c @@ -219,13 +219,13 @@ _serial_puts (const char *s,const int port) int _serial_getc(const int port) { - return NS16550_getc(PORT); + return NS16550_getc(PORT, port); }
int _serial_tstc(const int port) { - return NS16550_tstc(PORT); + return NS16550_tstc(PORT, port); }
void diff --git a/include/ns16550.h b/include/ns16550.h index 9ea81e9..fa3e62e 100644 --- a/include/ns16550.h +++ b/include/ns16550.h @@ -160,6 +160,6 @@ typedef volatile struct NS16550 *NS16550_t;
void NS16550_init (NS16550_t com_port, int baud_divisor); void NS16550_putc (NS16550_t com_port, char c); -char NS16550_getc (NS16550_t com_port); -int NS16550_tstc (NS16550_t com_port); +char NS16550_getc (NS16550_t regs, unsigned int port); +int NS16550_tstc (NS16550_t regs, unsigned int port); void NS16550_reinit (NS16550_t com_port, int baud_divisor);