linux-kernel - Re: [PATCH] staging: dgnc: replace dgnc_offset

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Message-ID: <56F539EA.6090708@bfs.de>
Date:	Fri, 25 Mar 2016 14:15:22 +0100
From:	walter harms <wharms@....de>
To:	Daeseok Youn <daeseok.youn@...il.com>
CC:	lidza.louina@...il.com, markh@...pro.net,
	gregkh@...uxfoundation.org, driverdev-devel@...uxdriverproject.org,
	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] staging: dgnc: replace dgnc_offset_table with bit shift.



Am 25.03.2016 12:33, schrieb Daeseok Youn:
> the dgnc_offset_table has a same value with (1 << port).
> So I tried to replace dgnc_offset_table array with 1 << port.
> And also there are redundant assignments(tmp and current_port)
> inside while loop for checking uart port, and remove them.
> 
> Signed-off-by: Daeseok Youn <daeseok.youn@...il.com>
> ---
> Greg, This patch depends on previous patches.
> here are links(previous):
> 1. https://lkml.org/lkml/2016/3/24/661
> 2. https://lkml.org/lkml/2016/3/24/663
> 
> if those patches are failed to merge, I will send them again after
> fixing them.
> 
> thanks.
> 
>  drivers/staging/dgnc/dgnc_neo.c | 44 +++++++++++++++++++----------------------
>  1 file changed, 20 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/staging/dgnc/dgnc_neo.c b/drivers/staging/dgnc/dgnc_neo.c
> index d732e6e..8b6bc73 100644
> --- a/drivers/staging/dgnc/dgnc_neo.c
> +++ b/drivers/staging/dgnc/dgnc_neo.c
> @@ -77,9 +77,6 @@ struct board_ops dgnc_neo_ops = {
>  	.send_immediate_char =		neo_send_immediate_char
>  };
>  
> -static uint dgnc_offset_table[8] = { 0x01, 0x02, 0x04, 0x08,
> -				     0x10, 0x20, 0x40, 0x80 };
> -
>  /*
>   * This function allows calls to ensure that all outstanding
>   * PCI writes have been completed, by doing a PCI read against
> @@ -923,9 +920,7 @@ static irqreturn_t neo_intr(int irq, void *voidbrd)
>  	struct dgnc_board *brd = voidbrd;
>  	struct channel_t *ch;
>  	int port = 0;
> -	int type = 0;
> -	int current_port;
> -	u32 tmp;
> +	int type;
>  	u32 uart_poll;
>  	unsigned long flags;
>  	unsigned long flags2;
> @@ -960,28 +955,29 @@ static irqreturn_t neo_intr(int irq, void *voidbrd)
>  
>  	/* At this point, we have at least SOMETHING to service, dig further... */
>  
> -	current_port = 0;
> -
>  	/* Loop on each port */
>  	while ((uart_poll & 0xff) != 0) {
> -		tmp = uart_poll;
> -
> -		/* Check current port to see if it has interrupt pending */
> -		if ((tmp & dgnc_offset_table[current_port]) != 0) {
> -			port = current_port;
> -			type = tmp >> (8 + (port * 3));
> -			type &= 0x7;
> -		} else {
> -			current_port++;
> -			continue;
> -		}
> +		int i;
>  
> -		/* Remove this port + type from uart_poll */
> -		uart_poll &= ~(dgnc_offset_table[port]);
> +		type = 0;
>  
> -		if (!type) {
> -			/* If no type, just ignore it, and move onto next port */
> -			continue;
> +		for (i = port; i < MAXPORTS; i++) {
> +			unsigned int offset_table = 0x1 << i;
> +
> +			/* Check current port to see
> +			 * if it has interrupt pending
> +			 */
> +			if ((uart_poll & offset_table) != 0) {
> +				port = i;
> +				type = uart_poll >> (8 + (port * 3));
> +				type &= 0x7;
> +
> +				/* Remove this port + type from uart_poll */
> +				uart_poll &= ~(offset_table);

	why not: art_poll &= ~ (0x1 << i);
	then you can easy eliminate offset_table	

	btw: why do you need i ?

	re,
	 wh

> +			}
> +
> +			if (type)
> +				break;
>  		}
>  
>  		/* Switch on type of interrupt we have */