Re: [PATCH v2] serial: 8250_bcm7271: improve bcm7271 8250 port

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Aug 17, 2023 at 02:13:18PM -0700, Justin Chen wrote:
> The 8250 BCM7271 UART is not a direct match to PORT_16550A and other
> generic ports do not match its hardware capabilities. PORT_ALTR matches
> the rx trigger levels, but its vendor configurations are not compatible.
> Unfortunately this means we need to create another port to fully capture
> the hardware capabilities of the BCM7271 UART.
> 
> To alleviate some latency pressures, we default the rx trigger level to 8.
> 
> Signed-off-by: Justin Chen <justin.chen@broadcom.com>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> Acked-by: Doug Berger <opendmb@gmail.com>
> ---
>  drivers/tty/serial/8250/8250_bcm7271.c | 4 +---
>  drivers/tty/serial/8250/8250_port.c    | 8 ++++++++
>  include/uapi/linux/serial_core.h       | 3 +++
>  3 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_bcm7271.c b/drivers/tty/serial/8250/8250_bcm7271.c
> index d4b05d7ad9e8..aa5aff046756 100644
> --- a/drivers/tty/serial/8250/8250_bcm7271.c
> +++ b/drivers/tty/serial/8250/8250_bcm7271.c
> @@ -1042,7 +1042,7 @@ static int brcmuart_probe(struct platform_device *pdev)
>  	dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not ");
>  
>  	memset(&up, 0, sizeof(up));
> -	up.port.type = PORT_16550A;
> +	up.port.type = PORT_BCM7271;
>  	up.port.uartclk = clk_rate;
>  	up.port.dev = dev;
>  	up.port.mapbase = mapbase;
> @@ -1056,8 +1056,6 @@ static int brcmuart_probe(struct platform_device *pdev)
>  		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
>  	up.port.dev = dev;
>  	up.port.private_data = priv;
> -	up.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
> -	up.port.fifosize = 32;
>  
>  	/* Check for a fixed line number */
>  	ret = of_alias_get_id(np, "serial");
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 16aeb1420137..9f05745e221b 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -322,6 +322,14 @@ static const struct serial8250_config uart_config[] = {
>  		.rxtrig_bytes   = {2, 66, 130, 194},
>  		.flags          = UART_CAP_FIFO,
>  	},
> +	[PORT_BCM7271] = {
> +		.name		= "Broadcom BCM7271 UART",
> +		.fifo_size	= 32,
> +		.tx_loadsz	= 32,
> +		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
> +		.rxtrig_bytes	= {1, 8, 16, 30},
> +		.flags		= UART_CAP_FIFO | UART_CAP_AFE
> +	},
>  };
>  
>  /* Uart divisor latch read */
> diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
> index 281fa286555c..9646629496ab 100644
> --- a/include/uapi/linux/serial_core.h
> +++ b/include/uapi/linux/serial_core.h
> @@ -144,6 +144,9 @@
>  /* Blackfin bf5xx */
>  #define PORT_BFIN	75
>  
> +/* Broadcom BCM7271 UART */
> +#define PORT_BCM7271    76
> +
>  /* Broadcom SB1250, etc. SOC */
>  #define PORT_SB1250_DUART	77
>  
> -- 
> 2.7.4
> 



Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
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