linux-kernel - Re: [PATCH v1 tty] 8250: microchip: pci1xxxx: Refactor TX Burst code to use pre-existing APIs

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Date: Thu, 22 Feb 2024 18:01:34 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Rengarajan S <rengarajan.s@...rochip.com>
cc: kumaravel.thiagarajan@...rochip.com, tharunkumar.pasumarthi@...rochip.com, 
    gregkh@...uxfoundation.org, jirislaby@...nel.org, 
    linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org, 
    unglinuxdriver@...rochip.com
Subject: Re: [PATCH v1 tty] 8250: microchip: pci1xxxx: Refactor TX Burst code
 to use pre-existing APIs

On Thu, 22 Feb 2024, Rengarajan S wrote:

> Updated the TX Burst implementation by changing the circular buffer
> processing with the pre-existing APIs in kernel. Also updated conditional
> statements and alignment issues for better readability.
> 
> Signed-off-by: Rengarajan S <rengarajan.s@...rochip.com>
> ---

> @@ -434,16 +435,7 @@ static void pci1xxxx_tx_burst(struct uart_port *port, u32 uart_status)
>  
>  	xmit = &port->state->xmit;
>  
> -	if (port->x_char) {
> -		writeb(port->x_char, port->membase + UART_TX);
> -		port->icount.tx++;
> -		port->x_char = 0;
> -		return;
> -	}
> -
> -	if ((uart_tx_stopped(port)) || (uart_circ_empty(xmit))) {
> -		port->ops->stop_tx(port);
> -	} else {
> +	if (!(port->x_char)) {
>  		data_empty_count = (pci1xxxx_read_burst_status(port) &
>  				    UART_BST_STAT_TX_COUNT_MASK) >> 8;
>  		do {
> @@ -453,15 +445,22 @@ static void pci1xxxx_tx_burst(struct uart_port *port, u32 uart_status)
>  						    &data_empty_count,
>  						    &valid_byte_count);
>  
> -			port->icount.tx++;
>  			if (uart_circ_empty(xmit))
>  				break;
>  		} while (data_empty_count && valid_byte_count);
> +	} else {
> +		writeb(port->x_char, port->membase + UART_TX);
> +		port->icount.tx++;
> +		port->x_char = 0;
> +		return;

Why you made this reorganization for x_char handling?? It seems 
entirely wrong thing to do, x_char should have precendence over 
sending normal chars.

This patch would have been some much simpler to review if it would have 
not attempted to n things in one go, please try to split into sensible 
changes.


-- 
 i.