Subject: Re: [PATCH 03/16] c_can: simplify arbitration register handling

From: Marc Kleine-Budde <[email-masked]>
Date: Mon, 09 Sep 2013 11:16:26 +0200

On 09/09/2013 09:25 AM, Benedikt Spranger wrote:
> The IF1/2 Arbitration register of the C_CAN/D_CAN ip core is internaly
> a 32bit register. Do not use two different 16bit variables to handle
> the IF1/2 Arbitration register.
> 
> Signed-off-by: Benedikt Spranger <[email-masked]>

Looks good, nitpit inline.

Marc
> ---
>  drivers/net/can/c_can/c_can.c | 27 ++++++++++++++-------------
>  1 file changed, 14 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
> index 081620b..bdb7bcd 100644
> --- a/drivers/net/can/c_can/c_can.c
> +++ b/drivers/net/can/c_can/c_can.c
> @@ -117,9 +117,9 @@
>  				IF_COMM_DATAA | IF_COMM_DATAB)
>  
>  /* IFx arbitration */
> -#define IF_ARB_MSGVAL		BIT(15)
> -#define IF_ARB_MSGXTD		BIT(14)
> -#define IF_ARB_TRANSMIT		BIT(13)
> +#define IF_ARB_MSGVAL		BIT(31)
> +#define IF_ARB_MSGXTD		BIT(30)
> +#define IF_ARB_TRANSMIT		BIT(29)
>  
>  /* IFx message control */
>  #define IF_MCONT_NEWDAT		BIT(15)
> @@ -133,6 +133,7 @@
>  #define IF_MCONT_TXRQST		BIT(8)
>  #define IF_MCONT_EOB		BIT(7)
>  #define IF_MCONT_DLC_MASK	0xf
> +#define IF_MCONT_DLC_MAX	8

It's not used, is it?

>  
>  /*
>   * IFx register masks:
> @@ -336,7 +337,7 @@ static void c_can_write_msg_object(struct net_device *dev,
>  			int iface, struct can_frame *frame, int objno)
>  {
>  	int i;
> -	u16 flags = 0;
> +	u32 flags = IF_ARB_MSGVAL;
>  	unsigned int id;
>  	struct c_can_priv *priv = netdev_priv(dev);
>  
> @@ -349,11 +350,11 @@ static void c_can_write_msg_object(struct net_device *dev,
>  	} else
>  		id = ((frame->can_id & CAN_SFF_MASK) << 18);
>  
> -	flags |= IF_ARB_MSGVAL;
> +	id |= flags;
>  
>  	priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface),
>  				IFX_WRITE_LOW_16BIT(id));
> -	priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface), flags |
> +	priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface),
>  				IFX_WRITE_HIGH_16BIT(id));
>  
>  	for (i = 0; i < frame->can_dlc; i += 2) {
> @@ -439,7 +440,7 @@ static void c_can_handle_lost_msg_obj(struct net_device *dev,
>  
>  static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl)
>  {
> -	u16 flags, data;
> +	u16 data;
>  	int i;
>  	unsigned int val;
>  	struct c_can_priv *priv = netdev_priv(dev);
> @@ -455,16 +456,15 @@ static int c_can_read_msg_object(struct net_device *dev, int iface, int ctrl)
>  
>  	frame->can_dlc = get_can_dlc(ctrl & 0x0F);
>  
> -	flags =	priv->read_reg(priv, C_CAN_IFACE(ARB2_REG, iface));
> -	val = priv->read_reg(priv, C_CAN_IFACE(ARB1_REG, iface)) |
> -		(flags << 16);
> +	val = (priv->read_reg(priv, C_CAN_IFACE(ARB2_REG, iface)) << 16);
> +	val |= priv->read_reg(priv, C_CAN_IFACE(ARB1_REG, iface));
>  
> -	if (flags & IF_ARB_MSGXTD)
> +	if (val & IF_ARB_MSGXTD)
>  		frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG;
>  	else
>  		frame->can_id = (val >> 18) & CAN_SFF_MASK;
>  
> -	if (flags & IF_ARB_TRANSMIT)
> +	if (val & IF_ARB_TRANSMIT)
>  		frame->can_id |= CAN_RTR_FLAG;
>  	else {
>  		for (i = 0; i < frame->can_dlc; i += 2) {
> @@ -500,10 +500,11 @@ static void c_can_setup_receive_object(struct net_device *dev, int iface,
>  	priv->write_reg(priv, C_CAN_IFACE(MASK2_REG, iface),
>  			IFX_WRITE_HIGH_16BIT(mask) | BIT(13));
>  
> +	id |= IF_ARB_MSGVAL;
>  	priv->write_reg(priv, C_CAN_IFACE(ARB1_REG, iface),
>  			IFX_WRITE_LOW_16BIT(id));
>  	priv->write_reg(priv, C_CAN_IFACE(ARB2_REG, iface),
> -			(IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id)));
> +			(IFX_WRITE_HIGH_16BIT(id)));
>  
>  	priv->write_reg(priv, C_CAN_IFACE(MSGCTRL_REG, iface), mcont);
>  	c_can_object_put(dev, iface, objno, IF_COMM_ALL & ~IF_COMM_TXRQST);
> 

-- 
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