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Date: Mon, 02 Nov 2009 20:49:21 +0100
From: Wolfgang Grandegger <wg@...ndegger.com>
To: Christian Pellegrin <chripell@...e.org>
CC: socketcan-core@...ts.berlios.de,
spi-devel-general@...ts.sourceforge.net, netdev@...r.kernel.org,
pthomas8589@...il.com
Subject: Re: [PATCH] can: Driver for the Microchip MCP251x SPI CAN controllers
I assume this is v2 of the patch.
Christian Pellegrin wrote:
> Signed-off-by: Christian Pellegrin <chripell@...e.org>
> ---
> drivers/net/can/Kconfig | 6 +
> drivers/net/can/Makefile | 1 +
> drivers/net/can/mcp251x.c | 1164 ++++++++++++++++++++++++++++++++++
> include/linux/can/platform/mcp251x.h | 36 +
> 4 files changed, 1207 insertions(+), 0 deletions(-)
> create mode 100644 drivers/net/can/mcp251x.c
> create mode 100644 include/linux/can/platform/mcp251x.h
>
[snip]
> diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
> new file mode 100644
> index 0000000..9471bb7
> --- /dev/null
> +++ b/drivers/net/can/mcp251x.c
[snip]
> +static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame,
> + int tx_buf_idx)
> +{
> + u32 sid, eid, exide, rtr;
> + u8 buf[SPI_TRANSFER_BUF_LEN];
> +
> + exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */
> + if (exide)
> + sid = (frame->can_id & CAN_EFF_MASK) >> 18;
> + else
> + sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */
> + eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */
> + rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */
> +
> + buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx);
> + buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT;
> + buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) |
> + (exide << SIDL_EXIDE_SHIFT) |
> + ((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK);
> + buf[TXBEID8_OFF] = GET_BYTE(eid, 1);
> + buf[TXBEID0_OFF] = GET_BYTE(eid, 0);
> + buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc;
Two spaces before "=".
> + memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc);
> + mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx);
> + mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx), TXBCTRL_TXREQ);
> +}
> +
[snip]
> +static int mcp251x_open(struct net_device *net)
> +{
> + struct mcp251x_priv *priv = netdev_priv(net);
> + struct spi_device *spi = priv->spi;
> + struct mcp251x_platform_data *pdata = spi->dev.platform_data;
> + int ret;
> +
> + if (pdata->transceiver_enable)
> + pdata->transceiver_enable(1);
> +
> + priv->force_quit = 0;
> + priv->tx_skb = NULL;
> + priv->tx_len = 0;
> +
> + ret = request_irq(spi->irq, mcp251x_can_isr,
> + IRQF_TRIGGER_FALLING, DEVICE_NAME, net);
> + if (ret) {
> + dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq);
> + return ret;
> + }
Here the transceiver should be switched off!?
> + mcp251x_hw_wakeup(spi);
> + mcp251x_hw_reset(spi);
> + ret = mcp251x_setup(net, priv, spi);
> + if (ret) {
> + free_irq(spi->irq, net);
> + if (pdata->transceiver_enable)
> + pdata->transceiver_enable(0);
> + return ret;
> + }
> + mcp251x_set_normal_mode(spi);
> + netif_wake_queue(net);
> +
> + return 0;
> +}
> +
[snip]
> +static void mcp251x_irq_work_handler(struct work_struct *ws)
> +{
> + struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv,
> + irq_work);
> + struct spi_device *spi = priv->spi;
> + struct net_device *net = priv->net;
> + u8 txbnctrl;
> + u8 intf;
> + enum can_state new_state;
> +
> + if (priv->after_suspend) {
> + mdelay(10);
> + mcp251x_hw_reset(spi);
> + mcp251x_setup(net, priv, spi);
> + if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
> + mcp251x_set_normal_mode(spi);
> + } else if (priv->after_suspend & AFTER_SUSPEND_UP) {
> + netif_device_attach(net);
> + /* Clean since we lost tx buffer */
> + if (priv->tx_skb || priv->tx_len) {
> + mcp251x_clean(net);
> + netif_wake_queue(net);
> + }
> + mcp251x_set_normal_mode(spi);
> + } else {
> + mcp251x_hw_sleep(spi);
> + }
> + priv->after_suspend = 0;
> + }
> +
> + if (priv->can.restart_ms == 0 && priv->can.state == CAN_STATE_BUS_OFF) {
> + while (!priv->force_quit && !freezing(current) &&
> + (intf = mcp251x_read_reg(spi, CANINTF)))
> + mcp251x_write_bits(spi, CANINTF, intf, 0x00);
Assigning variables within if or while expressions is not allowed. I
wonder why checkpatch did not spot it.
> + return;
> + }
> +
> + while (!priv->force_quit && !freezing(current)) {
> + u8 eflag = mcp251x_read_reg(spi, EFLG);
> + int can_id = 0, data1 = 0;
> +
> + mcp251x_write_reg(spi, EFLG, 0x00);
> +
> + if (priv->restart_tx) {
> + priv->restart_tx = 0;
> + mcp251x_write_reg(spi, TXBCTRL(0), 0);
> + if (priv->tx_skb || priv->tx_len)
> + mcp251x_clean(net);
> + netif_wake_queue(net);
> + can_id |= CAN_ERR_RESTARTED;
> + }
> +
> + if (priv->wake) {
> + /* Wait whilst the device wakes up */
> + mdelay(10);
> + priv->wake = 0;
> + }
> +
> + intf = mcp251x_read_reg(spi, CANINTF);
> + mcp251x_write_bits(spi, CANINTF, intf, 0x00);
> +
> + /* Update can state */
> + if (eflag & EFLG_TXBO) {
> + new_state = CAN_STATE_BUS_OFF;
> + can_id |= CAN_ERR_BUSOFF;
> + } else if (eflag & EFLG_TXEP) {
> + new_state = CAN_STATE_ERROR_PASSIVE;
> + can_id |= CAN_ERR_CRTL;
> + data1 |= CAN_ERR_CRTL_TX_PASSIVE;
> + } else if (eflag & EFLG_RXEP) {
> + new_state = CAN_STATE_ERROR_PASSIVE;
> + can_id |= CAN_ERR_CRTL;
> + data1 |= CAN_ERR_CRTL_RX_PASSIVE;
> + } else if (eflag & EFLG_TXWAR) {
> + new_state = CAN_STATE_ERROR_WARNING;
> + can_id |= CAN_ERR_CRTL;
> + data1 |= CAN_ERR_CRTL_TX_WARNING;
> + } else if (eflag & EFLG_RXWAR) {
> + new_state = CAN_STATE_ERROR_WARNING;
> + can_id |= CAN_ERR_CRTL;
> + data1 |= CAN_ERR_CRTL_RX_WARNING;
> + } else {
> + new_state = CAN_STATE_ERROR_ACTIVE;
> + }
> +
> + /* Update can state statistics */
> + switch (priv->can.state) {
> + case CAN_STATE_ERROR_ACTIVE:
> + if (new_state >= CAN_STATE_ERROR_WARNING &&
> + new_state <= CAN_STATE_BUS_OFF)
> + priv->can.can_stats.error_warning++;
> + case CAN_STATE_ERROR_WARNING: /* fallthrough */
> + if (new_state >= CAN_STATE_ERROR_PASSIVE &&
> + new_state <= CAN_STATE_BUS_OFF)
> + priv->can.can_stats.error_passive++;
> + break;
> + default:
> + break;
> + }
> + priv->can.state = new_state;
> +
> + if ((intf & CANINTF_ERRIF) || (can_id & CAN_ERR_RESTARTED)) {
> + struct sk_buff *skb;
> + struct can_frame *frame;
> +
> + /* Create error frame */
> + skb = alloc_can_err_skb(net, &frame);
> + if (skb) {
> + /* Set error frame flags based on bus state */
> + frame->can_id = can_id;
> + frame->data[1] = data1;
> +
> + /* Update net stats for overflows */
> + if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) {
> + if (eflag & EFLG_RX0OVR)
> + net->stats.rx_over_errors++;
> + if (eflag & EFLG_RX1OVR)
> + net->stats.rx_over_errors++;
> + frame->can_id |= CAN_ERR_CRTL;
> + frame->data[1] |=
> + CAN_ERR_CRTL_RX_OVERFLOW;
> + }
> +
> + netif_rx(skb);
> + } else {
> + dev_info(&spi->dev,
> + "cannot allocate error skb\n");
> + }
> + }
> +
> + if (priv->can.state == CAN_STATE_BUS_OFF) {
> + if (priv->can.restart_ms == 0) {
> + can_bus_off(net);
> + mcp251x_hw_sleep(spi);
> + return;
> + }
> + }
> +
> + if (intf == 0)
> + break;
> +
> + if (intf & CANINTF_WAKIF)
> + complete(&priv->awake);
> +
> + if (intf & CANINTF_MERRF) {
> + /* If there are pending Tx buffers, restart queue */
> + txbnctrl = mcp251x_read_reg(spi, TXBCTRL(0));
> + if (!(txbnctrl & TXBCTRL_TXREQ)) {
> + if (priv->tx_skb || priv->tx_len)
> + mcp251x_clean(net);
> + netif_wake_queue(net);
> + }
> + }
> +
> + if (intf & (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)) {
> + net->stats.tx_packets++;
> + net->stats.tx_bytes += priv->tx_len - 1;
> + if (priv->tx_len) {
> + can_get_echo_skb(net, 0);
> + priv->tx_len = 0;
> + }
> + netif_wake_queue(net);
> + }
> +
> + if (intf & CANINTF_RX0IF)
> + mcp251x_hw_rx(spi, 0);
> +
> + if (intf & CANINTF_RX1IF)
> + mcp251x_hw_rx(spi, 1);
> + }
> +}
> +
> +static const struct net_device_ops mcp251x_netdev_ops = {
> + .ndo_open = mcp251x_open,
> + .ndo_stop = mcp251x_stop,
> + .ndo_start_xmit = mcp251x_hard_start_xmit,
> +};
> +
> +static int __devinit mcp251x_can_probe(struct spi_device *spi)
> +{
> + struct net_device *net;
> + struct mcp251x_priv *priv;
> + struct mcp251x_platform_data *pdata = spi->dev.platform_data;
> + int ret = -ENODEV;
> +
> + if (!pdata)
> + /* Platform data is required for osc freq */
> + goto error_out;
> +
> + /* Allocate can/net device */
> + net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX);
> + if (!net) {
> + ret = -ENOMEM;
> + goto error_alloc;
> + }
> +
> + net->netdev_ops = &mcp251x_netdev_ops;
> + net->flags |= IFF_ECHO;
Remove spaces, please.
> + priv = netdev_priv(net);
> + priv->can.bittiming_const = &mcp251x_bittiming_const;
> + priv->can.do_set_mode = mcp251x_do_set_mode;
> + priv->can.clock.freq = pdata->oscillator_frequency / 2;
> + priv->can.do_set_bittiming = mcp251x_do_set_bittiming;
> + priv->net = net;
> + dev_set_drvdata(&spi->dev, priv);
> +
> + priv->spi = spi;
> + mutex_init(&priv->spi_lock);
> +
> + /* If requested, allocate DMA buffers */
> + if (mcp251x_enable_dma) {
> + spi->dev.coherent_dma_mask = ~0;
> +
> + /*
> + * Minimum coherent DMA allocation is PAGE_SIZE, so allocate
> + * that much and share it between Tx and Rx DMA buffers.
> + */
> + priv->spi_tx_buf = dma_alloc_coherent(&spi->dev,
> + PAGE_SIZE,
> + &priv->spi_tx_dma,
> + GFP_DMA);
> +
> + if (priv->spi_tx_buf) {
> + priv->spi_rx_buf = (u8 *)(priv->spi_tx_buf +
> + (PAGE_SIZE / 2));
> + priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
> + (PAGE_SIZE / 2));
> + } else {
> + /* Fall back to non-DMA */
> + mcp251x_enable_dma = 0;
> + }
> + }
> +
> + /* Allocate non-DMA buffers */
> + if (!mcp251x_enable_dma) {
> + priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
> + if (!priv->spi_tx_buf) {
> + ret = -ENOMEM;
> + goto error_tx_buf;
> + }
> + priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
> + if (!priv->spi_tx_buf) {
> + ret = -ENOMEM;
> + goto error_rx_buf;
> + }
> + }
> +
> + if (pdata->power_enable)
> + pdata->power_enable(1);
> +
> + /* Call out to platform specific setup */
> + if (pdata->board_specific_setup)
> + pdata->board_specific_setup(spi);
> +
> + SET_NETDEV_DEV(net, &spi->dev);
> +
> + priv->wq = create_freezeable_workqueue("mcp251x_wq");
> +
> + INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
> + INIT_WORK(&priv->irq_work, mcp251x_irq_work_handler);
> +
> + init_completion(&priv->awake);
> +
> + /* Configure the SPI bus */
> + spi->mode = SPI_MODE_0;
> + spi->bits_per_word = 8;
> + spi_setup(spi);
> +
> + if (!mcp251x_hw_probe(spi)) {
> + dev_info(&spi->dev, "Probe failed\n");
> + goto error_probe;
> + }
> + mcp251x_hw_sleep(spi);
> +
> + if (pdata->transceiver_enable)
> + pdata->transceiver_enable(0);
> +
> + ret = register_candev(net);
> + if (ret >= 0) {
if (!ret) ?
> + dev_info(&spi->dev, "probed\n");
> + return ret;
> + }
Shouldn't the power be switched off?
> +error_probe:
> + if (!mcp251x_enable_dma)
> + kfree(priv->spi_rx_buf);
> +error_rx_buf:
> + if (!mcp251x_enable_dma)
> + kfree(priv->spi_tx_buf);
> +error_tx_buf:
> + free_candev(net);
> + if (mcp251x_enable_dma)
> + dma_free_coherent(&spi->dev, PAGE_SIZE,
> + priv->spi_tx_buf, priv->spi_tx_dma);
> +error_alloc:
> + dev_err(&spi->dev, "probe failed\n");
> +error_out:
> + return ret;
> +}
> +
[snip]
We are close...
Wolfgang.
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