Re: [PATCH v3 4/7] can: Add Nuvoton NCT6694 CAN support

Marc Kleine-Budde
2024-12-11T09:59:52Z

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On 10.12.2024 18:45:21, Ming Yu wrote:
> This driver supports Socket CANfd functionality for NCT6694 MFD
> device based on USB interface.

Please use the rx-offload helper, otherwise the CAN frames might be
revived out of order.

>
> Signed-off-by: Ming Yu <tmyu0@nuvoton.com>
> ---
> MAINTAINERS | 1 +
> drivers/net/can/Kconfig | 10 +
> drivers/net/can/Makefile | 1 +
> drivers/net/can/nct6694_canfd.c | 920 ++++++++++++++++++++++++++++++++
> 4 files changed, 932 insertions(+)
> create mode 100644 drivers/net/can/nct6694_canfd.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a190f2b08fa3..eb5d46825e71 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16548,6 +16548,7 @@ S: Supported
> F: drivers/gpio/gpio-nct6694.c
> F: drivers/i2c/busses/i2c-nct6694.c
> F: drivers/mfd/nct6694.c
> +F: drivers/net/can/nct6694_canfd.c
> F: include/linux/mfd/nct6694.h
>
> NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
> diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
> index cf989bea9aa3..130e98ec28a5 100644
> --- a/drivers/net/can/Kconfig
> +++ b/drivers/net/can/Kconfig
> @@ -200,6 +200,16 @@ config CAN_SUN4I
> To compile this driver as a module, choose M here: the module will
> be called sun4i_can.
>
> +config CAN_NCT6694
> + tristate "Nuvoton NCT6694 Socket CANfd support"
> + depends on MFD_NCT6694
> + help
> + If you say yes to this option, support will be included for Nuvoton
> + NCT6694, a USB device to socket CANfd controller.
> +
> + This driver can also be built as a module. If so, the module will
> + be called nct6694_canfd.
> +
> config CAN_TI_HECC
> depends on ARM
> tristate "TI High End CAN Controller"
> diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
> index a71db2cfe990..4a6b5b9d6c2b 100644
> --- a/drivers/net/can/Makefile
> +++ b/drivers/net/can/Makefile
> @@ -28,6 +28,7 @@ obj-$(CONFIG_CAN_JANZ_ICAN3) += janz-ican3.o
> obj-$(CONFIG_CAN_KVASER_PCIEFD) += kvaser_pciefd.o
> obj-$(CONFIG_CAN_MSCAN) += mscan/
> obj-$(CONFIG_CAN_M_CAN) += m_can/
> +obj-$(CONFIG_CAN_NCT6694) += nct6694_canfd.o
> obj-$(CONFIG_CAN_PEAK_PCIEFD) += peak_canfd/
> obj-$(CONFIG_CAN_SJA1000) += sja1000/
> obj-$(CONFIG_CAN_SUN4I) += sun4i_can.o
> diff --git a/drivers/net/can/nct6694_canfd.c b/drivers/net/can/nct6694_canfd.c
> new file mode 100644
> index 000000000000..54f20f0681e2
> --- /dev/null
> +++ b/drivers/net/can/nct6694_canfd.c
> @@ -0,0 +1,920 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton NCT6694 Socket CANfd driver based on USB interface.
> + *
> + * Copyright (C) 2024 Nuvoton Technology Corp.
> + */
> +
> +#include <linux/can/dev.h>
> +#include <linux/ethtool.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/nct6694.h>
> +#include <linux/module.h>
> +#include <linux/netdevice.h>
> +#include <linux/platform_device.h>
> +
> +#define DRVNAME "nct6694-can"
> +
> +/* Host interface */
> +#define NCT6694_CAN_MOD 0x05
> +
> +/* Message Channel*/
> +/* Command 00h */
> +#define NCT6694_CAN_CMD0_OFFSET(idx) (idx ? 0x0100 : 0x0000)
> +#define NCT6694_CAN_CTRL1_MON BIT(0)
> +#define NCT6694_CAN_CTRL1_NISO BIT(1)
> +#define NCT6694_CAN_CTRL1_LBCK BIT(2)
> +
> +/* Command 01h */
> +#define NCT6694_CAN_CMD1_OFFSET 0x0001
> +
> +/* Command 02h */
> +#define NCT6694_CAN_CMD2_OFFSET(idx, mask) \
> + ({ typeof(mask) mask_ = (mask); \
> + idx ? ((0x80 | (mask_ & 0xFF)) << 8 | 0x02) : \
> + ((0x00 | (mask_ & 0xFF)) << 8 | 0x02); })
> +
> +#define NCT6694_CAN_EVENT_ERR BIT(0)
> +#define NCT6694_CAN_EVENT_STATUS BIT(1)
> +#define NCT6694_CAN_EVENT_TX_EVT BIT(2)
> +#define NCT6694_CAN_EVENT_RX_EVT BIT(3)
> +#define NCT6694_CAN_EVENT_REC BIT(4)
> +#define NCT6694_CAN_EVENT_TEC BIT(5)
> +#define NCT6694_CAN_EVT_TX_FIFO_EMPTY BIT(7) /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_DATA_LOST BIT(5) /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_HALF_FULL BIT(6) /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_DATA_IN BIT(7)
> +
> +/* Command 10h */
> +#define NCT6694_CAN_CMD10_OFFSET(buf_cnt) \
> + (((buf_cnt) & 0xFF) << 8 | 0x10)
> +#define NCT6694_CAN_TAG_CAN0 0xC0
> +#define NCT6694_CAN_TAG_CAN1 0xC1
> +#define NCT6694_CAN_FLAG_EFF BIT(0)
> +#define NCT6694_CAN_FLAG_RTR BIT(1)
> +#define NCT6694_CAN_FLAG_FD BIT(2)
> +#define NCT6694_CAN_FLAG_BRS BIT(3)
> +#define NCT6694_CAN_FLAG_ERR BIT(4)
> +
> +/* Command 11h */
> +#define NCT6694_CAN_CMD11_OFFSET(idx, buf_cnt) \
> + ({ typeof(buf_cnt) buf_cnt_ = (buf_cnt); \
> + idx ? ((0x80 | (buf_cnt_ & 0xFF)) << 8 | 0x11) : \
> + ((0x00 | (buf_cnt_ & 0xFF)) << 8 | 0x11); })
> +
> +#define NCT6694_CAN_RX_QUOTA 64
> +
> +enum nct6694_event_err {
> + NCT6694_CAN_EVT_NO_ERROR,
^^^ add _ERR_
> + NCT6694_CAN_EVT_CRC_ERROR,
> + NCT6694_CAN_EVT_STUFF_ERROR,
> + NCT6694_CAN_EVT_ACK_ERROR,
> + NCT6694_CAN_EVT_FORM_ERROR,
> + NCT6694_CAN_EVT_BIT_ERROR,
> + NCT6694_CAN_EVT_TIMEOUT_ERROR,
> + NCT6694_CAN_EVT_UNKNOWN_ERROR,
> +};
> +
> +enum nct6694_event_status {
> + NCT6694_CAN_EVT_ERROR_ACTIVE,
^^^ add _STATUS_
> + NCT6694_CAN_EVT_ERROR_PASSIVE,
> + NCT6694_CAN_EVT_BUS_OFF,
> + NCT6694_CAN_EVT_WARNING,
> +};
> +
> +struct __packed nct6694_can_setting {
> + __le32 nbr;
> + __le32 dbr;
> + u8 active;
> + u8 reserved[3];
> + __le16 ctrl1;
> + __le16 ctrl2;
> + __le32 nbtp;
> + __le32 dbtp;
> +};
> +
> +struct __packed nct6694_can_information {
> + u8 tx_fifo_cnt;
> + u8 rx_fifo_cnt;
> + __le16 reserved;
u8 reserved[2];
> + __le32 can_clk;
> +};
> +
> +struct __packed nct6694_can_event {
> + u8 err1;
> + u8 status1;
> + u8 tx_evt1;
> + u8 rx_evt1;
> + u8 rec1;
> + u8 tec1;
> + u8 reserved1[2];
> + u8 err2;
> + u8 status2;
> + u8 tx_evt2;
> + u8 rx_evt2;
> + u8 rec2;
> + u8 tec2;
> + u8 reserved2[2];
> +};

Create an extra struct that only describes a channel

struct __packed nct6694_can_event_channel {
u8 err;
u8 status;
u8 tx_evt;
u8 rx_evt;
u8 rec;
u8 tec;
u8 reserved[2];
}

and put an array of 2 into struct __packed nct6694_can_event.

> +
> +struct __packed nct6694_can_xmit {
> + u8 tag;
> + u8 flag;
> + u8 reserved;
> + u8 dlc;
> + __le32 id;
> + u8 data[64];
> + u8 msg_buf[72];

Why is the message so long? What's in the msg_buf?

> +};
> +
> +struct nct6694_can_priv {
> + struct can_priv can; /* must be the first member */
> + struct net_device *ndev;
> + struct nct6694 *nct6694;
> + struct mutex lock;

What does lock protect?

> + struct sk_buff *tx_skb;
> + struct workqueue_struct *wq;
> + struct work_struct tx_work;
> + unsigned char *tx_buf;
void *
> + unsigned char *rx_buf;
void *
> + unsigned char can_idx;
> + bool tx_busy;

IMHO it makes no sense to have tx_skb and tx_busy

> +};
> +
> +static const struct can_bittiming_const nct6694_can_bittiming_nominal_const = {
> + .name = DRVNAME,
> + .tseg1_min = 2,
> + .tseg1_max = 256,
> + .tseg2_min = 2,
> + .tseg2_max = 128,
> + .sjw_max = 128,
> + .brp_min = 1,
> + .brp_max = 511,
> + .brp_inc = 1,
> +};
> +
> +static const struct can_bittiming_const nct6694_can_bittiming_data_const = {
> + .name = DRVNAME,
> + .tseg1_min = 1,
> + .tseg1_max = 32,
> + .tseg2_min = 1,
> + .tseg2_max = 16,
> + .sjw_max = 16,
> + .brp_min = 1,
> + .brp_max = 31,
> + .brp_inc = 1,
> +};
> +
> +static void nct6694_can_clean(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> + if (priv->tx_skb || priv->tx_busy)
> + ndev->stats.tx_errors++;
> + dev_kfree_skb(priv->tx_skb);
> + if (priv->tx_busy)
> + can_free_echo_skb(priv->ndev, 0, NULL);
> + priv->tx_skb = NULL;
> + priv->tx_busy = false;
> +}
> +
> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> + struct can_berr_counter *bec)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_event *evt = (struct nct6694_can_event *)priv->rx_buf;
> + u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> + int ret;
> +
> + guard(mutex)(&priv->lock);
> +
> + ret = nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD2_OFFSET(priv->can_idx, mask),
> + sizeof(struct nct6694_can_event),
> + evt);
> + if (ret < 0)
> + return ret;
> +
> + bec->rxerr = priv->can_idx ? evt->rec2 : evt->rec1;
> + bec->txerr = priv->can_idx ? evt->tec2 : evt->tec1;
> +
> + return 0;
> +}
> +
> +static int nct6694_can_handle_lost_msg(struct net_device *ndev)
> +{
> + struct net_device_stats *stats = &ndev->stats;
> + struct sk_buff *skb;
> + struct can_frame *frame;
> +
> + netdev_err(ndev, "RX FIFO overflow, message(s) lost.\n");
> +
> + stats->rx_errors++;
> + stats->rx_over_errors++;
> +
> + skb = alloc_can_err_skb(ndev, &frame);
> + if (unlikely(!skb))
> + return 0;
> +
> + frame->can_id |= CAN_ERR_CRTL;
> + frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> +
> + netif_receive_skb(skb);
> +
> + return 1;
> +}
> +
> +static void nct6694_can_read_fifo(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_xmit *xmit = (struct nct6694_can_xmit *)priv->rx_buf;
> + struct net_device_stats *stats = &ndev->stats;
> + struct canfd_frame *cf;
> + struct sk_buff *skb;
> + int can_idx = priv->can_idx;
> + u32 id;
> + int ret;
> + u8 fd_format = 0;
bool - no need to init
> +
> + guard(mutex)(&priv->lock);
> +
> + ret = nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD11_OFFSET(can_idx, 1),
> + sizeof(struct nct6694_can_xmit), xmit);
> + if (ret < 0)
> + return;
> +
> + /* Check type of frame and create skb */
> + fd_format = xmit->flag & NCT6694_CAN_FLAG_FD;
> + if (fd_format)
> + skb = alloc_canfd_skb(ndev, &cf);
> + else
> + skb = alloc_can_skb(ndev, (struct can_frame **)&cf);
> +
> + if (!skb) {
> + stats->rx_dropped++;
> + return;
> + }
> +
> + cf->len = xmit->dlc;

what does xmit->dlc contain? The DLC or the length?

> +
> + /* Get ID and set flag by its type(Standard ID format or Ext ID format) */
> + id = le32_to_cpu(xmit->id);
> + if (xmit->flag & NCT6694_CAN_FLAG_EFF) {
> + /*
> + * In case the Extended ID frame is received, the standard
> + * and extended part of the ID are swapped in the register,
> + * so swap them back to obtain the correct ID.
> + */

You comment doesn't match the code.

> + id |= CAN_EFF_FLAG;
> + }
> +
> + cf->can_id = id;
> +
> + /* Set ESI flag */
> + if (xmit->flag & NCT6694_CAN_FLAG_ERR) {
> + cf->flags |= CANFD_ESI;
> + netdev_dbg(ndev, "ESI Error\n");
> + }
> +
> + /* Set RTR and BRS */
> + if (!fd_format && (xmit->flag & NCT6694_CAN_FLAG_RTR)) {
> + cf->can_id |= CAN_RTR_FLAG;
> + } else {
> + if (xmit->flag & NCT6694_CAN_FLAG_BRS)
> + cf->flags |= CANFD_BRS;
> +
> + memcpy(cf->data, xmit->data, cf->len);
> +
> + stats->rx_bytes += cf->len;
> + }
> +
> + stats->rx_packets++;
> +
> + netif_receive_skb(skb);
> +}
> +
> +static int nct6694_can_do_rx_poll(struct net_device *ndev, int quota)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_event *evt = (struct nct6694_can_event *)priv->rx_buf;
> + int can_idx = priv->can_idx;
> + u32 pkts = 0;
> + u8 mask_rx = NCT6694_CAN_EVENT_RX_EVT;
> + u8 rx_evt;
> +
> + for (;;) {
> + scoped_guard(mutex, &priv->lock) {
> + nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD2_OFFSET(can_idx, mask_rx),
> + sizeof(struct nct6694_can_event), evt);
> +
> + rx_evt = can_idx ? evt->rx_evt2 : evt->rx_evt1;
> + }
> +
> + if (rx_evt & NCT6694_CAN_EVT_RX_DATA_LOST)
> + nct6694_can_handle_lost_msg(ndev);
> +
> + /* No data */
> + if ((rx_evt & NCT6694_CAN_EVT_RX_DATA_IN) == 0)
> + break;
> +
> + if (quota <= 0)
> + break;
> +
> + nct6694_can_read_fifo(ndev);
> + quota--;
> + pkts++;
> + }
> +
> + return pkts;
> +}
> +
> +static int nct6694_can_handle_lec_err(struct net_device *ndev, u8 bus_err)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &ndev->stats;
> + struct can_frame *cf;
> + struct sk_buff *skb;
> +
> + if (bus_err == NCT6694_CAN_EVT_NO_ERROR)
> + return 0;
> +
> + priv->can.can_stats.bus_error++;
> + stats->rx_errors++;
> +
> + /* Propagate the error condition to the CAN stack. */
> + skb = alloc_can_err_skb(ndev, &cf);
> +
> + if (unlikely(!skb))
> + return 0;
> +
> + /* Read the error counter register and check for new errors. */
> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +
> + switch (bus_err) {
> + case NCT6694_CAN_EVT_CRC_ERROR:
> + cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
> + break;
> +
> + case NCT6694_CAN_EVT_STUFF_ERROR:
> + cf->data[2] |= CAN_ERR_PROT_STUFF;
> + break;
> +
> + case NCT6694_CAN_EVT_ACK_ERROR:
> + cf->data[3] = CAN_ERR_PROT_LOC_ACK;
> + break;
> +
> + case NCT6694_CAN_EVT_FORM_ERROR:
> + cf->data[2] |= CAN_ERR_PROT_FORM;
> + break;
> +
> + case NCT6694_CAN_EVT_BIT_ERROR:
> + cf->data[2] |= CAN_ERR_PROT_BIT |
> + CAN_ERR_PROT_BIT0 |
> + CAN_ERR_PROT_BIT1;
> + break;
> +
> + case NCT6694_CAN_EVT_TIMEOUT_ERROR:
> + cf->data[2] |= CAN_ERR_PROT_UNSPEC;
> + break;
> +
> + case NCT6694_CAN_EVT_UNKNOWN_ERROR:
> + cf->data[2] |= CAN_ERR_PROT_UNSPEC;
> + /*
> + * It means 'unspecified'(the value is '0').
> + * But it is not sure if it's ok to send an error package
> + * without specific error bit.
> + */
> + break;
> +
> + default:
> + break;
> + }
> +
> + /* Reset the error counter, ack the IRQ and re-enable the counter. */
> + stats->rx_packets++;
> + stats->rx_bytes += cf->can_dlc;
> + netif_receive_skb(skb);
> +
> + return 1;
> +}
> +
> +static int nct6694_can_handle_state_change(struct net_device *ndev,
> + enum can_state new_state)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &ndev->stats;
> + struct can_frame *cf;
> + struct sk_buff *skb;
> + struct can_berr_counter bec;
> +
> + switch (new_state) {
> + case CAN_STATE_ERROR_ACTIVE:
> + priv->can.can_stats.error_warning++;
> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> + break;
> + case CAN_STATE_ERROR_WARNING:
> + priv->can.can_stats.error_warning++;
> + priv->can.state = CAN_STATE_ERROR_WARNING;
> + break;
> + case CAN_STATE_ERROR_PASSIVE:
> + priv->can.can_stats.error_passive++;
> + priv->can.state = CAN_STATE_ERROR_PASSIVE;
> + break;
> + case CAN_STATE_BUS_OFF:
> + priv->can.state = CAN_STATE_BUS_OFF;
> + priv->can.can_stats.bus_off++;
> + can_bus_off(ndev);
> + break;
> + default:
> + break;
> + }
> +
> + /* propagate the error condition to the CAN stack */
> + skb = alloc_can_err_skb(ndev, &cf);
> + if (unlikely(!skb))
> + return 0;
> +
> + nct6694_can_get_berr_counter(ndev, &bec);
> +
> + switch (new_state) {
> + case CAN_STATE_ERROR_WARNING:
> + /* error warning state */
> + cf->can_id |= CAN_ERR_CRTL;
> + cf->data[1] = (bec.txerr > bec.rxerr) ? CAN_ERR_CRTL_TX_WARNING :
> + CAN_ERR_CRTL_RX_WARNING;
> + cf->data[6] = bec.txerr;
> + cf->data[7] = bec.rxerr;
> + break;
> + case CAN_STATE_ERROR_PASSIVE:
> + /* error passive state */
> + cf->can_id |= CAN_ERR_CRTL;
> + cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
> + if (bec.txerr > 127)
> + cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
> + cf->data[6] = bec.txerr;
> + cf->data[7] = bec.rxerr;
> + break;
> + case CAN_STATE_BUS_OFF:
> + /* bus-off state */
> + cf->can_id |= CAN_ERR_BUSOFF;
> + break;
> + default:
> + break;
> + }
> +
> + stats->rx_packets++;
> + stats->rx_bytes += cf->can_dlc;
> + netif_receive_skb(skb);
> +
> + return 1;
> +}
> +
> +static int nct6694_can_handle_state_errors(struct net_device *ndev,
> + unsigned char can_status)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + int work_done = 0;
> +
> + if (can_status == NCT6694_CAN_EVT_ERROR_ACTIVE &&
> + priv->can.state != CAN_STATE_ERROR_ACTIVE) {
> + netdev_dbg(ndev, "Error, entered active state\n");
> + work_done += nct6694_can_handle_state_change(ndev,
> + CAN_STATE_ERROR_ACTIVE);
> + }
> +
> + if (can_status == NCT6694_CAN_EVT_WARNING &&
> + priv->can.state != CAN_STATE_ERROR_WARNING) {
> + netdev_dbg(ndev, "Error, entered warning state\n");
> + work_done += nct6694_can_handle_state_change(ndev,
> + CAN_STATE_ERROR_WARNING);
> + }
> +
> + if (can_status == NCT6694_CAN_EVT_ERROR_PASSIVE &&
> + priv->can.state != CAN_STATE_ERROR_PASSIVE) {
> + netdev_dbg(ndev, "Error, entered passive state\n");
> + work_done += nct6694_can_handle_state_change(ndev,
> + CAN_STATE_ERROR_PASSIVE);
> + }
> +
> + if (can_status == NCT6694_CAN_EVT_BUS_OFF &&
> + priv->can.state != CAN_STATE_BUS_OFF) {
> + netdev_dbg(ndev, "Error, entered bus-off state\n");
> + work_done += nct6694_can_handle_state_change(ndev,
> + CAN_STATE_BUS_OFF);
> + }
> +
> + return work_done;
> +}
> +
> +static int nct6694_can_poll(struct net_device *ndev, int quota)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_event *evt = (struct nct6694_can_event *)priv->rx_buf;
> + int can_idx = priv->can_idx;
> + int work_done = 0, ret;
> + u8 evt_mask = NCT6694_CAN_EVENT_ERR | NCT6694_CAN_EVENT_STATUS;
> + u8 bus_err, can_status;
> +
> + scoped_guard(mutex, &priv->lock) {
> + ret = nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD2_OFFSET(can_idx, evt_mask),
> + sizeof(struct nct6694_can_event), evt);
> + if (ret < 0)
> + return IRQ_NONE;

propagate the error

> +
> + if (can_idx) {
> + bus_err = evt->err2;
> + can_status = evt->status2;
> + } else {
> + bus_err = evt->err1;
> + can_status = evt->status1;
> + }
> + }
> +
> + /* Handle bus state changes */
> + work_done += nct6694_can_handle_state_errors(ndev, can_status);
> +
> + /* Handle lec errors on the bus */
> + if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
> + work_done += nct6694_can_handle_lec_err(ndev, bus_err);
> +
> + /* Handle RX events */
> + work_done += nct6694_can_do_rx_poll(ndev, quota - work_done);
> + return work_done;
> +}
> +
> +static void nct6694_can_tx_irq(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &ndev->stats;
> +
> + guard(mutex)(&priv->lock);
> + stats->tx_bytes += can_get_echo_skb(ndev, 0, NULL);
> + stats->tx_packets++;
> + priv->tx_busy = false;
> + netif_wake_queue(ndev);
> +}
> +
> +static irqreturn_t nct6694_can_irq(int irq, void *data)
> +{
> + struct net_device *ndev = data;
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_event *evt = (struct nct6694_can_event *)priv->rx_buf;
> + int can_idx = priv->can_idx;
> + int ret;
> + u8 mask_sts = NCT6694_CAN_EVENT_TX_EVT;
> + u8 tx_evt;
> +
> + scoped_guard(mutex, &priv->lock) {
> + ret = nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD2_OFFSET(can_idx, mask_sts),
> + sizeof(struct nct6694_can_event), evt);
> + if (ret < 0)
> + return IRQ_NONE;
> +
> + tx_evt = can_idx ? evt->tx_evt2 : evt->tx_evt1;
> + }
> +
> + if (tx_evt) {
> + nct6694_can_tx_irq(ndev);
> + } else {
> + ret = nct6694_can_poll(ndev, NCT6694_CAN_RX_QUOTA);
> + if (!ret)
> + return IRQ_NONE;
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int nct6694_can_start(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_setting *setting = (struct nct6694_can_setting *)priv->tx_buf;
> + const struct can_bittiming *n_bt = &priv->can.bittiming;
> + const struct can_bittiming *d_bt = &priv->can.data_bittiming;
> + int ret;
> +
> + guard(mutex)(&priv->lock);
> +
> + memset(priv->tx_buf, 0, sizeof(struct nct6694_can_setting));
> + setting->nbr = cpu_to_le32(n_bt->bitrate);
> + setting->dbr = cpu_to_le32(d_bt->bitrate);
> +
> + if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> + setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_CTRL1_MON);
> +
> + if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) &&
> + priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
> + setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_CTRL1_NISO);
> +
> + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
> + setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_CTRL1_LBCK);
> +
> + ret = nct6694_write_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD0_OFFSET(priv->can_idx),
> + sizeof(struct nct6694_can_setting), setting);
> + if (ret < 0)
> + return ret;
> +
> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +
> + return 0;
> +}
> +
> +static int nct6694_can_stop(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> + netif_stop_queue(ndev);
> + free_irq(ndev->irq, ndev);
> + destroy_workqueue(priv->wq);
> + priv->wq = NULL;
> + nct6694_can_clean(ndev);
> + priv->can.state = CAN_STATE_STOPPED;
> + close_candev(ndev);
> +
> + return 0;
> +}
> +
> +static int nct6694_can_set_mode(struct net_device *ndev, enum can_mode mode)
> +{
> + switch (mode) {
> + case CAN_MODE_START:
> + nct6694_can_clean(ndev);
> + nct6694_can_start(ndev);
> + netif_wake_queue(ndev);
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static int nct6694_can_open(struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + int ret;
> +
> + ret = open_candev(ndev);
> + if (ret)
> + return ret;
> +
> + ret = request_threaded_irq(ndev->irq, NULL,
> + nct6694_can_irq, IRQF_ONESHOT,
> + "nct6694_can", ndev);
> + if (ret) {
> + netdev_err(ndev, "Failed to request IRQ\n");
> + goto close_candev;
> + }
> +
> + priv->wq = alloc_ordered_workqueue("%s-nct6694_wq",
> + WQ_FREEZABLE | WQ_MEM_RECLAIM,
> + ndev->name);
> + if (!priv->wq) {
> + ret = -ENOMEM;
> + goto free_irq;
> + }
> +
> + priv->tx_skb = NULL;
> + priv->tx_busy = false;
> +
> + ret = nct6694_can_start(ndev);
> + if (ret)
> + goto destroy_wq;
> +
> + netif_start_queue(ndev);
> +
> + return 0;
> +
> +destroy_wq:
> + destroy_workqueue(priv->wq);
> +free_irq:
> + free_irq(ndev->irq, ndev);
> +close_candev:
> + close_candev(ndev);
> + return ret;
> +}
> +
> +static netdev_tx_t nct6694_can_start_xmit(struct sk_buff *skb,
> + struct net_device *ndev)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> + if (priv->tx_skb || priv->tx_busy) {
> + netdev_err(ndev, "hard_xmit called while tx busy\n");
> + return NETDEV_TX_BUSY;
> + }
> +
> + if (can_dev_dropped_skb(ndev, skb))
> + return NETDEV_TX_OK;

please drop first

> +
> + netif_stop_queue(ndev);
> + priv->tx_skb = skb;
> + queue_work(priv->wq, &priv->tx_work);
> +
> + return NETDEV_TX_OK;
> +}
> +
> +static void nct6694_can_tx(struct net_device *ndev, struct canfd_frame *cf)
> +{
> + struct nct6694_can_priv *priv = netdev_priv(ndev);
> + struct nct6694_can_xmit *xmit = (struct nct6694_can_xmit *)priv->tx_buf;
> + u32 txid = 0;
> +
> + memset(xmit, 0, sizeof(struct nct6694_can_xmit));
> +
> + if (priv->can_idx == 0)
> + xmit->tag = NCT6694_CAN_TAG_CAN0<;
> + else
> + xmit->tag = NCT6694_CAN_TAG_CAN1;
> +
> + if (cf->can_id & CAN_EFF_FLAG) {
> + txid = cf->can_id & CAN_EFF_MASK;
> + /*
> + * In case the Extended ID frame is transmitted, the
> + * standard and extended part of the ID are swapped
> + * in the register, so swap them back to send the
> + * correct ID.

You comment doesn't match the code.

> + */
> + xmit->flag |= NCT6694_CAN_FLAG_EFF;
> + } else {
> + txid = cf->can_id & CAN_SFF_MASK;
> + }
> +
> + xmit->id = cpu_to_le32(txid);
> + xmit->dlc = cf->len;
> +
> + if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) &&

No need to check ctrlmode

> + can_is_canfd_skb(priv->tx_skb)) {
> + xmit->flag |= NCT6694_CAN_FLAG_FD;
> + if (cf->flags & CANFD_BRS)
> + xmit->flag |= NCT6694_CAN_FLAG_BRS;
> + }
> +
> + if (cf->can_id & CAN_RTR_FLAG)
> + xmit->flag |= NCT6694_CAN_FLAG_RTR;

you can move this into the !can_is_canfd_skb branch of the if

> +
> + memcpy(xmit->data, cf->data, cf->len);
> +
> + nct6694_write_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD10_OFFSET(1),
> + sizeof(struct nct6694_can_xmit),
> + xmit);
> +}
> +
> +static void nct6694_can_tx_work(struct work_struct *work)
> +{
> + struct nct6694_can_priv *priv = container_of(work,
> + struct nct6694_can_priv,
> + tx_work);
> + struct net_device *ndev = priv->ndev;
> + struct canfd_frame *cf;
> +
> + guard(mutex)(&priv->lock);
> +
> + if (priv->tx_skb) {
> + if (priv->can.state == CAN_STATE_BUS_OFF) {
> + nct6694_can_clean(ndev);
> + } else {
> + cf = (struct canfd_frame *)priv->tx_skb->data;
> + nct6694_can_tx(ndev, cf);
> + priv->tx_busy = true;
> + can_put_echo_skb(priv->tx_skb, ndev, 0, 0);
> + priv->tx_skb = NULL;
> + }
> + }
> +}
> +
> +static const struct net_device_ops nct6694_can_netdev_ops = {
> + .ndo_open = nct6694_can_open,
> + .ndo_stop = nct6694_can_stop,
> + .ndo_start_xmit = nct6694_can_start_xmit,
> + .ndo_change_mtu = can_change_mtu,
> +};
> +
> +static const struct ethtool_ops nct6694_can_ethtool_ops = {
> + .get_ts_info = ethtool_op_get_ts_info,
> +};
> +
> +static int nct6694_can_get_clock(struct nct6694_can_priv *priv)
> +{
> + struct nct6694_can_information *info = (struct nct6694_can_information *)priv->rx_buf;
> + int ret;
> +
> + ret = nct6694_read_msg(priv->nct6694, NCT6694_CAN_MOD,
> + NCT6694_CAN_CMD1_OFFSET,
> + sizeof(struct nct6694_can_information),
> + info);
> + if (ret)
> + return ret;
> +
> + return le32_to_cpu(info->can_clk);
> +}
> +
> +static int nct6694_can_probe(struct platform_device *pdev)
> +{
> + const struct mfd_cell *cell = mfd_get_cell(pdev);
> + struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> + struct nct6694_can_priv *priv;
> + struct net_device *ndev;
> + int ret, irq, can_clk;
> +
> + irq = irq_create_mapping(nct6694->domain,
> + NCT6694_IRQ_CAN1 + cell->id);
> + if (!irq)
> + return -EINVAL;

propagate error value

> +
> + ndev = alloc_candev(sizeof(struct nct6694_can_priv), 1);
> + if (!ndev)
> + return -ENOMEM;
> +
> + ndev->irq = irq;
> + ndev->flags |= IFF_ECHO;
> + ndev->netdev_ops = &nct6694_can_netdev_ops;
> + ndev->ethtool_ops = &nct6694_can_ethtool_ops;
> +
> + priv = netdev_priv(ndev);
> + priv->nct6694 = nct6694;
> + priv->ndev = ndev;
> +
> + priv->tx_buf = devm_kcalloc(&pdev->dev, NCT6694_MAX_PACKET_SZ,
> + sizeof(unsigned char), GFP_KERNEL);

devm_kzalloc()
> + if (!priv->tx_buf) {
> + ret = -ENOMEM;
> + goto free_candev;
> + }
> +
> + priv->rx_buf = devm_kcalloc(&pdev->dev, NCT6694_MAX_PACKET_SZ,
> + sizeof(unsigned char), GFP_KERNEL);
devm_kzalloc()

> + if (!priv->rx_buf) {
> + ret = -ENOMEM;
> + goto free_candev;
> + }
> +
> + can_clk = nct6694_can_get_clock(priv);
> + if (can_clk < 0) {
> + ret = -EIO;

propagate the error value, don't overwrite it

move the dev_err_probe() here.

> + goto free_candev;
> + }
> +
> + mutex_init(&priv->lock);
> + INIT_WORK(&priv->tx_work, nct6694_can_tx_work);
> +
> + priv->can_idx = cell->id;
> + priv->can.state = CAN_STATE_STOPPED;
> + priv->can.clock.freq = can_clk;
> + priv->can.bittiming_const = &nct6694_can_bittiming_nominal_const;
> + priv->can.data_bittiming_const = &nct6694_can_bittiming_data_const;
> + priv->can.do_set_mode = nct6694_can_set_mode;
> + priv->can.do_get_berr_counter = nct6694_can_get_berr_counter;
> +
> + priv->can.ctrlmode = CAN_CTRLMODE_FD;
> +
> + priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
> + CAN_CTRLMODE_LISTENONLY |
> + CAN_CTRLMODE_FD |
> + CAN_CTRLMODE_FD_NON_ISO |
> + CAN_CTRLMODE_BERR_REPORTING;
> +
> + platform_set_drvdata(pdev, priv);
> + SET_NETDEV_DEV(priv->ndev, &pdev->dev);
> +
> + ret = register_candev(priv->ndev);
> + if (ret)
> + goto free_candev;
> +
> + return 0;
> +
> +free_candev:
> + free_candev(ndev);
> + return dev_err_probe(&pdev->dev, ret, "Probe failed\n");

Move the dev_err_probe() with an appropriate error message to where the
error occurs. If malloc fails, the kernel already prints for you, so
here it's only nct6694_can_get_clock() only.

> +}
> +
> +static void nct6694_can_remove(struct platform_device *pdev)
> +{
> + struct nct6694_can_priv *priv = platform_get_drvdata(pdev);
> +
> + cancel_work_sync(&priv->tx_work);
> + unregister_candev(priv->ndev);
> + free_candev(priv->ndev);
> +}
> +
> +static struct platform_driver nct6694_can_driver = {
> + .driver = {
> + .name = DRVNAME,
> + },
> + .probe = nct6694_can_probe,
> + .remove = nct6694_can_remove,
> +};
> +
> +module_platform_driver(nct6694_can_driver);
> +
> +MODULE_DESCRIPTION("USB-CAN FD driver for NCT6694");
> +MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:nct6694-can");
> --
> 2.34.1
>
>
>

regards,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung Nürnberg | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |

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