Subject: Re: [PATCH net-next-2.6 v6 06/20] can: EG20T PCH: Fix endianness issue

From: Marc Kleine-Budde <[email-masked]>
Date: Tue, 30 Nov 2010 13:05:43 +0100

On 11/30/2010 05:20 AM, Tomoya MORINAGA wrote:
> there is endianness issue both Tx and Rx.
> Currently, data is set like below.
> Register:
> MSB--LSB
> x x D0 D1
> x x D2 D3
> x x D4 D5
> x x D6 D7
> 
> But Data to be sent must be set like below.
> Register:
> MSB--LSB
> x x D1 D0
> x x D3 D2
> x x D5 D4
> x x D7 D6  (x means reserved area.)

The patch does more than fixing the endianess issue. Please split non
endianess related changes into seperate patch.

regards, Marc
> 
> Signed-off-by: Tomoya MORINAGA <tomoya-linux-ECg8zkTtlr0C6LszWs/[email-masked]>
> ---
>  drivers/net/can/pch_can.c |  118 +++++++++++++++++++++------------------------
>  1 files changed, 55 insertions(+), 63 deletions(-)
> 
> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
> index 6437e60..98e7e9f 100644
> --- a/drivers/net/can/pch_can.c
> +++ b/drivers/net/can/pch_can.c
> @@ -134,10 +134,7 @@ struct pch_can_if_regs {
>  	u32 id1;
>  	u32 id2;
>  	u32 mcont;
> -	u32 dataa1;
> -	u32 dataa2;
> -	u32 datab1;
> -	u32 datab2;
> +	u32 data[4];./internal/TsiStandard/appl/gendata/desc.c
>  	u32 rsv[13];
>  };
>  
> @@ -420,10 +417,10 @@ static void pch_can_clear_buffers(struct pch_can_priv *priv)
>  		iowrite32(0x0, &priv->regs->ifregs[0].id1);
>  		iowrite32(0x0, &priv->regs->ifregs[0].id2);
>  		iowrite32(0x0, &priv->regs->ifregs[0].mcont);
> -		iowrite32(0x0, &priv->regs->ifregs[0].dataa1);
> -		iowrite32(0x0, &priv->regs->ifregs[0].dataa2);
> -		iowrite32(0x0, &priv->regs->ifregs[0].datab1);
> -		iowrite32(0x0, &priv->regs->ifregs[0].datab2);
> +		iowrite32(0x0, &priv->regs->ifregs[0].data[0]);
> +		iowrite32(0x0, &priv->regs->ifregs[0].data[1]);
> +		iowrite32(0x0, &priv->regs->ifregs[0].data[2]);
> +		iowrite32(0x0, &priv->regs->ifregs[0].data[3]);
>  		iowrite32(PCH_CMASK_RDWR | PCH_CMASK_MASK |
>  			  PCH_CMASK_ARB | PCH_CMASK_CTRL,
>  			  &priv->regs->ifregs[0].cmask);
> @@ -437,10 +434,10 @@ static void pch_can_clear_buffers(struct pch_can_priv *priv)
>  		iowrite32(0x0, &priv->regs->ifregs[1].id1);
>  		iowrite32(0x0, &priv->regs->ifregs[1].id2);
>  		iowrite32(0x0, &priv->regs->ifregs[1].mcont);
> -		iowrite32(0x0, &priv->regs->ifregs[1].dataa1);
> -		iowrite32(0x0, &priv->regs->ifregs[1].dataa2);
> -		iowrite32(0x0, &priv->regs->ifregs[1].datab1);
> -		iowrite32(0x0, &priv->regs->ifregs[1].datab2);
> +		iowrite32(0x0, &priv->regs->ifregs[1].data[0]);
> +		iowrite32(0x0, &priv->regs->ifregs[1].data[1]);
> +		iowrite32(0x0, &priv->regs->ifregs[1].data[2]);
> +		iowrite32(0x0, &priv->regs->ifregs[1].data[3]);
>  		iowrite32(PCH_CMASK_RDWR | PCH_CMASK_MASK |
>  			  PCH_CMASK_ARB | PCH_CMASK_CTRL,
>  			  &priv->regs->ifregs[1].cmask);
> @@ -703,12 +700,13 @@ static int pch_can_rx_normal(struct net_device *ndev, u32 int_stat)
>  	canid_t id;
>  	u32 ide;
>  	u32 rtr;
> -	int i, j, k;
> +	int i, k;
>  	int rcv_pkts = 0;
>  	struct sk_buff *skb;
>  	struct can_frame *cf;
>  	struct pch_can_priv *priv = netdev_priv(ndev);
>  	struct net_device_stats *stats = &(priv->ndev->stats);
> +	u16 data_reg;
>  
>  	/* Reading the messsage object from the Message RAM */
>  	iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
> @@ -774,12 +772,10 @@ static int pch_can_rx_normal(struct net_device *ndev, u32 int_stat)
>  			      ((ioread32(&priv->regs->ifregs[0].mcont)) & 0x0f);
>  		}
>  
> -		for (i = 0, j = 0; i < cf->can_dlc; j++) {
> -			reg = ioread32(&priv->regs->ifregs[0].dataa1 + j*4);
> -			cf->data[i++] = cpu_to_le32(reg & 0xff);
> -			if (i == cf->can_dlc)
> -				break;
> -			cf->data[i++] = cpu_to_le32((reg >> 8) & 0xff);
> +		for (i = 0; i < cf->can_dlc; i += 2) {
> +			data_reg = ioread16(&priv->regs->ifregs[0].data[i / 2]);
> +			cf->data[i] = data_reg & 0xff;
> +			cf->data[i + 1] = data_reg >> 8;

this is endianess related....good

>  		}
>  
>  		netif_receive_skb(skb);
> @@ -815,72 +811,71 @@ RX_NEXT:
>  
>  	return rcv_pkts;
>  }
> -static int pch_can_rx_poll(struct napi_struct *napi, int quota)
> +
> +static void pch_can_tx_complete(struct net_device *ndev, u32 int_stat)
>  {
> -	struct net_device *ndev = napi->dev;
>  	struct pch_can_priv *priv = netdev_priv(ndev);
>  	struct net_device_stats *stats = &(priv->ndev->stats);
>  	u32 dlc;
> +
> +	can_get_echo_skb(ndev, int_stat - PCH_RX_OBJ_END - 1);
> +	iowrite32(PCH_CMASK_RX_TX_GET | PCH_CMASK_CLRINTPND,
> +		  &priv->regs->ifregs[1].cmask);
> +	pch_can_check_if_busy(&priv->regs->ifregs[1].creq, int_stat);
> +	dlc = get_can_dlc(ioread32(&priv->regs->ifregs[1].mcont) &
> +			  PCH_IF_MCONT_DLC);
> +	stats->tx_bytes += dlc;
> +	stats->tx_packets++;
> +	if (int_stat == PCH_TX_OBJ_END)
> +		netif_wake_queue(ndev);
> +}

but this is something else...please split into a seperate patch.

> +
> +static int pch_can_rx_poll(struct napi_struct *napi, int quota)
> +{
> +	struct net_device *ndev = napi->dev;
> +	struct pch_can_priv *priv = netdev_priv(ndev);
>  	u32 int_stat;
>  	int rcv_pkts = 0;
>  	u32 reg_stat;
>  
>  	int_stat = pch_can_int_pending(priv);
>  	if (!int_stat)
> -		return 0;
> +		goto end;
>  
> -INT_STAT:
> -	if (int_stat == PCH_STATUS_INT) {
> +	if ((int_stat == PCH_STATUS_INT) && (quota > 0)) {
>  		reg_stat = ioread32(&priv->regs->stat);
>  		if (reg_stat & (PCH_BUS_OFF | PCH_LEC_ALL)) {
> -			if ((reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL)
> +			if (reg_stat & PCH_BUS_OFF ||
> +			   (reg_stat & PCH_LEC_ALL) != PCH_LEC_ALL) {
>  				pch_can_error(ndev, reg_stat);
> +				quota--;
> +			}

dito

>  		}
>  
> -		if (reg_stat & PCH_TX_OK) {
> -			iowrite32(PCH_CMASK_RX_TX_GET,
> -				  &priv->regs->ifregs[1].cmask);
> -			pch_can_check_if_busy(&priv->regs->ifregs[1].creq,
> -					       ioread32(&priv->regs->intr));
> +		if (reg_stat & PCH_TX_OK)
>  			pch_can_bit_clear(&priv->regs->stat, PCH_TX_OK);
> -		}

dito
>  
>  		if (reg_stat & PCH_RX_OK)
>  			pch_can_bit_clear(&priv->regs->stat, PCH_RX_OK);
>  
>  		int_stat = pch_can_int_pending(priv);
> -		if (int_stat == PCH_STATUS_INT)
> -			goto INT_STAT;
>  	}
>  
> -MSG_OBJ:
> +	if (quota == 0)
> +		goto end;
> +
>  	if ((int_stat >= PCH_RX_OBJ_START) && (int_stat <= PCH_RX_OBJ_END)) {
> -		rcv_pkts = pch_can_rx_normal(ndev, int_stat);
> -		if (rcv_pkts < 0)
> -			return 0;
> +		rcv_pkts += pch_can_rx_normal(ndev, int_stat);
> +		quota -= rcv_pkts;
> +		if (quota < 0)
> +			goto end;

same here

>  	} else if ((int_stat >= PCH_TX_OBJ_START) &&
>  		   (int_stat <= PCH_TX_OBJ_END)) {
>  		/* Handle transmission interrupt */
> -		can_get_echo_skb(ndev, int_stat - PCH_RX_OBJ_END - 1);
> -		iowrite32(PCH_CMASK_RX_TX_GET | PCH_CMASK_CLRINTPND,
> -			  &priv->regs->ifregs[1].cmask);
> -		dlc = ioread32(&priv->regs->ifregs[1].mcont) &
> -			       PCH_IF_MCONT_DLC;
> -		pch_can_check_if_busy(&priv->regs->ifregs[1].creq, int_stat);
> -		if (dlc > 8)
> -			dlc = 8;
> -		stats->tx_bytes += dlc;
> -		stats->tx_packets++;
> -		if (int_stat == PCH_TX_OBJ_END)
> -			netif_wake_queue(ndev);
> +		pch_can_tx_complete(ndev, int_stat);

same here

>  	}
>  
> -	int_stat = pch_can_int_pending(priv);
> -	if (int_stat == PCH_STATUS_INT)
> -		goto INT_STAT;
> -	else if (int_stat >= 1 && int_stat <= 32)
> -		goto MSG_OBJ;
> -
> +end:
>  	napi_complete(napi);
>  	pch_can_set_int_enables(priv, PCH_CAN_ALL);
>  
> @@ -1013,10 +1008,10 @@ static int pch_close(struct net_device *ndev)
>  
>  static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
>  {
> -	int i, j;
>  	struct pch_can_priv *priv = netdev_priv(ndev);
>  	struct can_frame *cf = (struct can_frame *)skb->data;
>  	int tx_buffer_avail = 0;
> +	int i;
>  
>  	if (can_dropped_invalid_skb(ndev, skb))
>  		return NETDEV_TX_OK;
> @@ -1057,13 +1052,10 @@ static netdev_tx_t pch_xmit(struct sk_buff *skb, struct net_device *ndev)
>  	if (cf->can_id & CAN_RTR_FLAG)
>  		pch_can_bit_clear(&priv->regs->ifregs[1].id2, PCH_ID2_DIR);
>  
> -	for (i = 0, j = 0; i < cf->can_dlc; j++) {
> -		iowrite32(le32_to_cpu(cf->data[i++]),
> -			 (&priv->regs->ifregs[1].dataa1) + j*4);
> -		if (i == cf->can_dlc)
> -			break;
> -		iowrite32(le32_to_cpu(cf->data[i++] << 8),
> -			 (&priv->regs->ifregs[1].dataa1) + j*4);
> +	/* Copy data to register */
> +	for (i = 0; i < cf->can_dlc; i += 2) {
> +		iowrite16(cf->data[i] | (cf->data[i + 1] << 8),
> +			  &priv->regs->ifregs[1].data[i / 2]);

good.

>  	}
>  
>  	can_put_echo_skb(skb, ndev, tx_buffer_avail - PCH_RX_OBJ_END - 1);

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

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