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Date: Fri, 26 Nov 2010 10:52:28 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Tomoya MORINAGA <tomoya-linux@....okisemi.com>
CC: Wolfgang Grandegger <wg@...ndegger.com>,
Wolfram Sang <w.sang@...gutronix.de>,
Christian Pellegrin <chripell@...e.org>,
Barry Song <21cnbao@...il.com>,
Samuel Ortiz <sameo@...ux.intel.com>,
socketcan-core@...ts.berlios.de, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
andrew.chih.howe.khor@...el.com, qi.wang@...el.com,
margie.foster@...el.com, yong.y.wang@...el.com,
kok.howg.ewe@...el.com, joel.clark@...el.com
Subject: Re: [PATCH net-next-2.6 06/19 v5] can: EG20T PCH: Fix endianness
issue
On 11/26/2010 03:12 AM, Tomoya MORINAGA wrote:
> Fix endianness issue.
> 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.)
I whish you just fix the endianess issue in this patch. Makes it more
readable.
> For easy to read, some sub-functions are created.
>
> Modify complex "goto" to do~while.
This should go into a separate patch. Please don't introduce the
next_flag variable that you remove in a later patch.
>
> Signed-off-by: Tomoya MORINAGA <tomoya-linux@....okisemi.com>
> ---
> drivers/net/can/pch_can.c | 304 +++++++++++++++++++++++----------------------
> 1 files changed, 155 insertions(+), 149 deletions(-)
>
> diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
> index 6437e60..0ac2a75 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];
> 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);
> @@ -697,190 +694,202 @@ static irqreturn_t pch_can_interrupt(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> -static int pch_can_rx_normal(struct net_device *ndev, u32 int_stat)
> +static void pch_fifo_thresh(struct pch_can_priv *priv, int obj_id)
> +{
> + if (obj_id < PCH_FIFO_THRESH) {
> + iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL |
> + PCH_CMASK_ARB, &priv->regs->ifregs[0].cmask);
> +
> + /* Clearing the Dir bit. */
> + pch_can_bit_clear(&priv->regs->ifregs[0].id2, PCH_ID2_DIR);
> +
> + /* Clearing NewDat & IntPnd */
> + pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
> + PCH_IF_MCONT_INTPND);
> + pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_id);
> + } else if (obj_id > PCH_FIFO_THRESH) {
> + pch_can_int_clr(priv, obj_id);
> + } else if (obj_id == PCH_FIFO_THRESH) {
> + int cnt;
> + for (cnt = 0; cnt < PCH_FIFO_THRESH; cnt++)
> + pch_can_int_clr(priv, cnt + 1);
> + }
> +}
> +
> +static int pch_can_rx_msg_lost(struct net_device *ndev, int obj_id)
> +{
> + struct pch_can_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &(priv->ndev->stats);
> + struct sk_buff *skb;
> + struct can_frame *cf;
> +
> + netdev_dbg(priv->ndev, "Msg Obj is overwritten.\n");
> + pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
> + PCH_IF_MCONT_MSGLOST);
> + iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL,
> + &priv->regs->ifregs[0].cmask);
> + pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_id);
> +
> + skb = alloc_can_err_skb(ndev, &cf);
> + if (!skb)
> + return -ENOMEM;
> +
> + cf->can_id |= CAN_ERR_CRTL;
> + cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> + stats->rx_over_errors++;
> + stats->rx_errors++;
> +
> + netif_receive_skb(skb);
> +
> + return 0;
> +}
> +
> +static int pch_can_rx_normal(struct net_device *ndev, u32 obj_num, int quota)
> {
> u32 reg;
> canid_t id;
> - u32 ide;
> - u32 rtr;
> - int i, j, k;
> int rcv_pkts = 0;
> + int rtn;
> + int next_flag = 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);
> + int i;
> + u32 id2;
> + u16 data_reg;
>
> - /* Reading the messsage object from the Message RAM */
> - iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
> - pch_can_check_if_busy(&priv->regs->ifregs[0].creq, int_stat);
> + do {
> + /* Reading the messsage object from the Message RAM */
> + iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
> + pch_can_check_if_busy(&priv->regs->ifregs[0].creq, obj_num);
>
> - /* Reading the MCONT register. */
> - reg = ioread32(&priv->regs->ifregs[0].mcont);
> - reg &= 0xffff;
> + /* Reading the MCONT register. */
> + reg = ioread32(&priv->regs->ifregs[0].mcont);
> +
> + if (reg & PCH_IF_MCONT_EOB)
> + break;
>
> - for (k = int_stat; !(reg & PCH_IF_MCONT_EOB); k++) {
> /* If MsgLost bit set. */
> if (reg & PCH_IF_MCONT_MSGLOST) {
> - dev_err(&priv->ndev->dev, "Msg Obj is overwritten.\n");
> - pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
> - PCH_IF_MCONT_MSGLOST);
> - iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL,
> - &priv->regs->ifregs[0].cmask);
> - pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
> -
> - skb = alloc_can_err_skb(ndev, &cf);
> + rtn = pch_can_rx_msg_lost(ndev, obj_num);
> + if (!rtn)
> + netdev_err(ndev, "Can't get memory\n");
Your logic is broken, the function returns 0 on success, which makes it
print a error message.
In an OOM situation the system is under pressure anyway. On low end
systems it not good to print a message to the log. AFAICS no other can
driver does this.
> + rcv_pkts++;
> + quota--;
> + next_flag = 1;
> + } else if (!(reg & PCH_IF_MCONT_NEWDAT))
> + next_flag = 1;
Please don't introduce the next_flag, that is removed in a later patch.
> +
> + if (!next_flag) {
> + skb = alloc_can_skb(priv->ndev, &cf);
> if (!skb)
> return -ENOMEM;
>
> - priv->can.can_stats.error_passive++;
> - priv->can.state = CAN_STATE_ERROR_PASSIVE;
> - cf->can_id |= CAN_ERR_CRTL;
> - cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
> - cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
> - stats->rx_packets++;
> - stats->rx_bytes += cf->can_dlc;
> + /* Get Received data */
> + id2 = ioread32(&priv->regs->ifregs[0].id2);
> + if (id2 & PCH_ID2_XTD) {
> + id = (ioread32(&priv->regs->ifregs[0].id1) &
> + 0xffff);
> + id |= (((id2) & 0x1fff) << 16);
> + cf->can_id = id | CAN_EFF_FLAG;
> + } else {
> + id = ((id2 & (CAN_SFF_MASK << 2)) >> 2);
id = (id2 >> 2) & CAN_SFF_MASK;
this is IMHO more readable.
> + cf->can_id = id;
> + }
> +
> + if (id2 & PCH_ID2_DIR)
> + cf->can_id |= CAN_RTR_FLAG;
> +
> + cf->can_dlc = get_can_dlc((ioread32(&priv->regs->
> + ifregs[0].mcont)) & 0xF);
> +
> + 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;
& 0xff isn't needed, as cf->data is 8 bit wide.
> + cf->data[i + 1] = data_reg >> 8;
> + }
>
> netif_receive_skb(skb);
> rcv_pkts++;
> - goto RX_NEXT;
> - }
> - if (!(reg & PCH_IF_MCONT_NEWDAT))
> - goto RX_NEXT;
> -
> - skb = alloc_can_skb(priv->ndev, &cf);
> - if (!skb)
> - return -ENOMEM;
> -
> - /* Get Received data */
> - ide = ((ioread32(&priv->regs->ifregs[0].id2)) & PCH_ID2_XTD) >>
> - 14;
> - if (ide) {
> - id = (ioread32(&priv->regs->ifregs[0].id1) & 0xffff);
> - id |= (((ioread32(&priv->regs->ifregs[0].id2)) &
> - 0x1fff) << 16);
> - cf->can_id = (id & CAN_EFF_MASK) | CAN_EFF_FLAG;
> - } else {
> - id = (((ioread32(&priv->regs->ifregs[0].id2)) &
> - (CAN_SFF_MASK << 2)) >> 2);
> - cf->can_id = (id & CAN_SFF_MASK);
> - }
> + stats->rx_packets++;
> + quota--;
> + stats->rx_bytes += cf->can_dlc;
>
> - rtr = (ioread32(&priv->regs->ifregs[0].id2) & PCH_ID2_DIR);
> - if (rtr) {
> - cf->can_dlc = 0;
> - cf->can_id |= CAN_RTR_FLAG;
> - } else {
> - cf->can_dlc =
> - ((ioread32(&priv->regs->ifregs[0].mcont)) & 0x0f);
> + pch_fifo_thresh(priv, obj_num);
> }
> + obj_num++;
> + next_flag = 0;
> + } while (quota > 0);
>
> - 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);
> - }
> + return rcv_pkts;
> +}
>
> - netif_receive_skb(skb);
> - rcv_pkts++;
> - stats->rx_packets++;
> - stats->rx_bytes += cf->can_dlc;
> -
> - if (k < PCH_FIFO_THRESH) {
> - iowrite32(PCH_CMASK_RDWR | PCH_CMASK_CTRL |
> - PCH_CMASK_ARB, &priv->regs->ifregs[0].cmask);
> -
> - /* Clearing the Dir bit. */
> - pch_can_bit_clear(&priv->regs->ifregs[0].id2,
> - PCH_ID2_DIR);
> -
> - /* Clearing NewDat & IntPnd */
> - pch_can_bit_clear(&priv->regs->ifregs[0].mcont,
> - PCH_IF_MCONT_INTPND);
> - pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
> - } else if (k > PCH_FIFO_THRESH) {
> - pch_can_int_clr(priv, k);
> - } else if (k == PCH_FIFO_THRESH) {
> - int cnt;
> - for (cnt = 0; cnt < PCH_FIFO_THRESH; cnt++)
> - pch_can_int_clr(priv, cnt+1);
> - }
> -RX_NEXT:
> - /* Reading the messsage object from the Message RAM */
> - iowrite32(PCH_CMASK_RX_TX_GET, &priv->regs->ifregs[0].cmask);
> - pch_can_check_if_busy(&priv->regs->ifregs[0].creq, k);
> - reg = ioread32(&priv->regs->ifregs[0].mcont);
> - }
> +static void pch_can_tx_complete(struct net_device *ndev, u32 int_stat)
> +{
> + struct pch_can_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &(priv->ndev->stats);
> + u32 dlc;
>
> - return rcv_pkts;
> + 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);
> }
> +
> 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);
> - struct net_device_stats *stats = &(priv->ndev->stats);
> - u32 dlc;
> 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--;
> + }
> }
>
> - 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);
> - }
>
> 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);
> + quota -= rcv_pkts;
> + if (quota < 0)
> + goto end;
> } 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);
> }
>
> - 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);
>
The following hunk is a nice and clean patch. It fixes the endianess
issue, nothing more.
> @@ -1013,10 +1022,10 @@ 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 +1066,10 @@ 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]);
> }
>
> can_put_echo_skb(skb, ndev, tx_buffer_avail - PCH_RX_OBJ_END - 1);
cheers, Marc
--
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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