Subject: [RFC PATCH 06/15] tty: serial: samsung: add byte-order aware bit functions

From: [email-masked] (Krzysztof Kozlowski)
Date: Fri, 10 Jun 2016 14:17:41 +0200

On 06/08/2016 08:31 PM, Matthew Leach wrote:
> This driver makes use of the __set_bit() and __clear_bit() functions.
> When running under big-endian, these functions don't convert the bit
> indexes when working with peripheral registers, leading to the
> incorrect bits being set and cleared when running big-endian.
> 
> Add two new driver functions for setting and clearing bits that are
> byte-order aware.
> 
> Signed-off-by: Matthew Leach <[email-masked]>
> ---
> CC: Greg Kroah-Hartman <[email-masked]>
> CC: Jiri Slaby <[email-masked]>
> CC: linux-serial at vger.kernel.org
> CC: linux-kernel at vger.kernel.org
> ---
>  drivers/tty/serial/samsung.c | 16 +++++++---------
>  drivers/tty/serial/samsung.h | 29 +++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> index 99bb231..e4f53d5 100644
> --- a/drivers/tty/serial/samsung.c
> +++ b/drivers/tty/serial/samsung.c
> @@ -169,8 +169,7 @@ static void s3c24xx_serial_stop_tx(struct uart_port *port)
>  		return;
>  
>  	if (s3c24xx_serial_has_interrupt_mask(port))
> -		__set_bit(S3C64XX_UINTM_TXD,
> -			portaddrl(port, S3C64XX_UINTM));
> +		s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
>  	else
>  		disable_irq_nosync(ourport->tx_irq);
>  
> @@ -235,8 +234,7 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
>  
>  	/* Mask Tx interrupt */
>  	if (s3c24xx_serial_has_interrupt_mask(port))
> -		__set_bit(S3C64XX_UINTM_TXD,
> -			  portaddrl(port, S3C64XX_UINTM));
> +		s3c24xx_set_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
>  	else
>  		disable_irq_nosync(ourport->tx_irq);
>  
> @@ -269,8 +267,8 @@ static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
>  
>  	/* Unmask Tx interrupt */
>  	if (s3c24xx_serial_has_interrupt_mask(port))
> -		__clear_bit(S3C64XX_UINTM_TXD,
> -			    portaddrl(port, S3C64XX_UINTM));
> +		s3c24xx_clear_bit(port, S3C64XX_UINTM_TXD,
> +				  S3C64XX_UINTM);
>  	else
>  		enable_irq(ourport->tx_irq);
>  
> @@ -397,8 +395,8 @@ static void s3c24xx_serial_stop_rx(struct uart_port *port)
>  	if (rx_enabled(port)) {
>  		dbg("s3c24xx_serial_stop_rx: port=%p\n", port);
>  		if (s3c24xx_serial_has_interrupt_mask(port))
> -			__set_bit(S3C64XX_UINTM_RXD,
> -				portaddrl(port, S3C64XX_UINTM));
> +			s3c24xx_set_bit(port, S3C64XX_UINTM_RXD,
> +					S3C64XX_UINTM);
>  		else
>  			disable_irq_nosync(ourport->rx_irq);
>  		rx_enabled(port) = 0;
> @@ -1069,7 +1067,7 @@ static int s3c64xx_serial_startup(struct uart_port *port)
>  	spin_unlock_irqrestore(&port->lock, flags);
>  
>  	/* Enable Rx Interrupt */
> -	__clear_bit(S3C64XX_UINTM_RXD, portaddrl(port, S3C64XX_UINTM));
> +	s3c24xx_clear_bit(port, S3C64XX_UINTM_RXD, S3C64XX_UINTM);
>  
>  	dbg("s3c64xx_serial_startup ok\n");
>  	return ret;
> diff --git a/drivers/tty/serial/samsung.h b/drivers/tty/serial/samsung.h
> index 8818bdd..e45745a 100644
> --- a/drivers/tty/serial/samsung.h
> +++ b/drivers/tty/serial/samsung.h
> @@ -111,6 +111,7 @@ struct s3c24xx_uart_port {
>  
>  #define s3c24xx_dev_to_port(__dev) dev_get_drvdata(__dev)
>  
> +

This new line looks unnecessary. Beside that it looks okay:

Reviewed-by: Krzysztof Kozlowski <[email-masked]>

Best regards,
Krzysztof

>  /* register access controls */
>  
>  #define portaddr(port, reg) ((port)->membase + (reg))
> @@ -123,4 +124,32 @@ struct s3c24xx_uart_port {
>  #define wr_regb(port, reg, val) __raw_writeb(val, portaddr(port, reg))
>  #define wr_regl(port, reg, val) writel_relaxed(val, portaddr(port, reg))
>  
> +/* Byte-order aware bit setting/clearing functions. */
> +
> +static inline void s3c24xx_set_bit(struct uart_port *port, int idx,
> +				   unsigned int reg)
> +{
> +	unsigned long flags;
> +	u32 val;
> +
> +	local_irq_save(flags);
> +	val = rd_regl(port, reg);
> +	val |= (1 << idx);
> +	wr_regl(port, reg, val);
> +	local_irq_restore(flags);
> +}
> +
> +static inline void s3c24xx_clear_bit(struct uart_port *port, int idx,
> +				     unsigned int reg)
> +{
> +	unsigned long flags;
> +	u32 val;
> +
> +	local_irq_save(flags);
> +	val = rd_regl(port, reg);
> +	val &= ~(1 << idx);
> +	wr_regl(port, reg, val);
> +	local_irq_restore(flags);
> +}
> +
>  #endif
>