Hi Simon,
On 14.07.2017 15:50, Simon Glass wrote:
> On 13 July 2017 at 05:33, Stefan Roese <s...@denx.de> wrote:
>> Pasting longer lines into the U-Boot console prompt sometimes leads to
>> characters missing. One problem here is the small 16-byte FIFO of the
>> legacy NS16550 UART, e.g. on x86 platforms.
>>
>> This patch now introduces a Kconfig option to enable RX interrupt
>> buffer support for NS16550 style UARTs. With this option enabled, I was
>> able paste really long lines into the U-Boot console, without any
>> characters missing.
>>
>> Signed-off-by: Stefan Roese <s...@denx.de>
>> Cc: Simon Glass <s...@chromium.org>
>> Cc: Bin Meng <bmeng...@gmail.com>
>> ---
>> drivers/serial/Kconfig | 10 +++++
>> drivers/serial/ns16550.c | 106
>> ++++++++++++++++++++++++++++++++++++++++++++---
>> include/ns16550.h | 6 +++
>> 3 files changed, 117 insertions(+), 5 deletions(-)
>
> Reviewed-by: Simon Glass <s...@chromium.org>
>
> nits below
>
>>
>> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
>> index b7dd2ac103..8284febae3 100644
>> --- a/drivers/serial/Kconfig
>> +++ b/drivers/serial/Kconfig
>> @@ -64,6 +64,16 @@ config DM_SERIAL
>> implements serial_putc() etc. The uclass interface is
>> defined in include/serial.h.
>>
>> +config SERIAL_IRQ_BUFFER
>> + bool "Enable RX interrupt buffer for serial input"
>> + depends on DM_SERIAL
>> + default n
>> + help
>> + Enable RX interrupt buffer support for the serial driver.
>> + This enables pasting longer strings, even when the RX FIFO
>> + of the UART is not big enough (e.g. 16 bytes on the normal
>> + NS16550).
>> +
>> config SPL_DM_SERIAL
>> bool "Enable Driver Model for serial drivers in SPL"
>> depends on DM_SERIAL
>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
>> index e0e70244ce..686c088e1d 100644
>> --- a/drivers/serial/ns16550.c
>> +++ b/drivers/serial/ns16550.c
>> @@ -315,6 +315,80 @@ DEBUG_UART_FUNCS
>> #endif
>>
>> #ifdef CONFIG_DM_SERIAL
>> +
>> +#if CONFIG_IS_ENABLED(SERIAL_IRQ_BUFFER)
>> +
>> +#define BUF_COUNT 256
>> +
>> +static void rx_fifo_to_buf(struct udevice *dev)
>> +{
>> + struct NS16550 *const com_port = dev_get_priv(dev);
>> + struct ns16550_platdata *plat = dev->platdata;
>> +
>> + /* Read all available chars into buffer */
>> + while ((serial_in(&com_port->lsr) & UART_LSR_DR)) {
>> + plat->buf[plat->wr_ptr++] = serial_in(&com_port->rbr);
>> + plat->wr_ptr %= BUF_COUNT;
>> + }
>> +}
>> +
>> +static int rx_pending(struct udevice *dev)
>> +{
>> + struct ns16550_platdata *plat = dev->platdata;
>> +
>> + /*
>> + * At startup it may happen, that some already received chars are
>> + * "stuck" in the RX FIFO, even with the interrupt enabled. This
>> + * RX FIFO flushing makes sure, that these chars are read out and
>> + * the RX interrupts works as expected.
>> + */
>> + rx_fifo_to_buf(dev);
>> +
>> + return plat->rd_ptr != plat->wr_ptr ? 1 : 0;
>> +}
>> +
>> +static int rx_get(struct udevice *dev)
>> +{
>> + struct ns16550_platdata *plat = dev->platdata;
>> + char val;
>> +
>> + val = plat->buf[plat->rd_ptr++];
>> + plat->rd_ptr %= BUF_COUNT;
>> +
>> + return val;
>> +}
>> +
>> +void ns16550_handle_irq(void *data)
>> +{
>> + struct udevice *dev = (struct udevice *)data;
>> + struct NS16550 *const com_port = dev_get_priv(dev);
>> +
>> + /* Check if interrupt is pending */
>> + if (serial_in(&com_port->iir) & UART_IIR_NO_INT)
>> + return;
>> +
>> + /* Flush all available characters from the RX FIFO into the RX
>> buffer */
>> + rx_fifo_to_buf(dev);
>> +}
>> +
>> +#else /* CONFIG_SERIAL_IRQ_BUFFER */
>> +
>> +static int rx_pending(struct udevice *dev)
>> +{
>> + struct NS16550 *const com_port = dev_get_priv(dev);
>> +
>> + return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
>> +}
>> +
>> +static int rx_get(struct udevice *dev)
>> +{
>> + struct NS16550 *const com_port = dev_get_priv(dev);
>> +
>> + return serial_in(&com_port->rbr);
>> +}
>> +
>> +#endif /* CONFIG_SERIAL_IRQ_BUFFER */
>> +
>> static int ns16550_serial_putc(struct udevice *dev, const char ch)
>> {
>> struct NS16550 *const com_port = dev_get_priv(dev);
>> @@ -340,19 +414,17 @@ static int ns16550_serial_pending(struct udevice *dev,
>> bool input)
>> struct NS16550 *const com_port = dev_get_priv(dev);
>>
>> if (input)
>> - return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
>> + return rx_pending(dev);
>> else
>> return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
>> }
>>
>> static int ns16550_serial_getc(struct udevice *dev)
>> {
>> - struct NS16550 *const com_port = dev_get_priv(dev);
>> -
>> - if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
>> + if (!ns16550_serial_pending(dev, true))
>> return -EAGAIN;
>>
>> - return serial_in(&com_port->rbr);
>> + return rx_get(dev);
>> }
>>
>> static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
>> @@ -375,6 +447,21 @@ int ns16550_serial_probe(struct udevice *dev)
>> com_port->plat = dev_get_platdata(dev);
>> NS16550_init(com_port, -1);
>>
>> +#if CONFIG_IS_ENABLED(SERIAL_IRQ_BUFFER)
>> + if (gd->flags & GD_FLG_RELOC) {
>> + struct ns16550_platdata *plat = dev->platdata;
>> +
>> + /* Allocate the RX buffer */
>> + plat->buf = malloc(BUF_COUNT);
>> +
>> + /* Install the interrupt handler */
>> + irq_install_handler(plat->irq, ns16550_handle_irq, dev);
>
> Do we need to remove this in the remove() method?
All interrupts are disabled before booting into the OS, so strictly it
should not be necessary. But yes, I think its a good idea to remove
the irq handler upon driver device. I'll change this in v2.
>> +
>> + /* Enable RX interrupts */
>> + serial_out(UART_IER_RDI, &com_port->ier);
>> + }
>> +#endif
>> +
>> return 0;
>> }
>>
>> @@ -459,6 +546,15 @@ int ns16550_serial_ofdata_to_platdata(struct udevice
>> *dev)
>> if (port_type == PORT_JZ4780)
>> plat->fcr |= UART_FCR_UME;
>>
>> +#if CONFIG_IS_ENABLED(SERIAL_IRQ_BUFFER)
>> + plat->irq = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
>> + "interrupts", 0);
>> + if (!plat->irq) {
>> + debug("ns16550 interrupt not provided\n");
>> + return -EINVAL;
>> + }
>> +#endif
>> +
>> return 0;
>> }
>> #endif
>> diff --git a/include/ns16550.h b/include/ns16550.h
>> index 5fcbcd2e74..70d1ec8e6a 100644
>> --- a/include/ns16550.h
>> +++ b/include/ns16550.h
>> @@ -58,6 +58,12 @@ struct ns16550_platdata {
>> int clock;
>> int reg_offset;
>> u32 fcr;
>> +
>> + int irq;
>> +
>> + char *buf;
>> + int rd_ptr;
>> + int wr_ptr;
>
> Please add comments to document these members.
Sure. Will add in v2.
Thanks,
Stefan
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