Re: [PATCH v10 2/2] can: esd: add support for esd GmbH PCIe/402 CAN interface family
From: Stefan Mätje
Date: Wed Nov 22 2023 - 10:43:48 EST
Will change the patch to follow your last comment below.
Am Mittwoch, den 22.11.2023, 00:04 +0900 schrieb Vincent Mailhol:
> Two last comments. These are not withstanding.
>
> On Tue. 21 Nov. 2023 at 02:57, Stefan Mätje <stefan.maetje@xxxxxx> wrote:
> > This patch adds support for the PCI based PCIe/402 CAN interface family
> > from esd GmbH that is available with various form factors
> > (https://esd.eu/en/products/402-series-can-interfaces).
> >
> > All boards utilize a FPGA based CAN controller solution developed
> > by esd (esdACC). For more information on the esdACC see
> > https://esd.eu/en/products/esdacc.
> >
> > This driver detects all available CAN interface board variants of
> > the family but atm. operates the CAN-FD capable devices in
> > Classic-CAN mode only! A later patch will introduce the CAN-FD
> > functionality in this driver.
> >
> > Co-developed-by: Thomas Körper <thomas.koerper@xxxxxx>
> > Signed-off-by: Thomas Körper <thomas.koerper@xxxxxx>
> > Signed-off-by: Stefan Mätje <stefan.maetje@xxxxxx>
> > ---
>
> (...)
>
> > diff --git a/drivers/net/can/esd/esdacc.c b/drivers/net/can/esd/esdacc.c
> > new file mode 100644
> > index 000000000000..c990e60c09f1
> > --- /dev/null
> > +++ b/drivers/net/can/esd/esdacc.c
> > @@ -0,0 +1,761 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/* Copyright (C) 2015 - 2016 Thomas Körper, esd electronic system design gmbh
> > + * Copyright (C) 2017 - 2023 Stefan Mätje, esd electronics gmbh
> > + */
> > +
> > +#include "esdacc.h"
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/delay.h>
> > +#include <linux/io.h>
> > +#include <linux/ktime.h>
> > +
> > +/* esdACC ID register layout */
> > +#define ACC_ID_ID_MASK GENMASK(28, 0)
> > +#define ACC_ID_EFF_FLAG BIT(29)
> > +
> > +/* esdACC DLC register layout */
> > +#define ACC_DLC_DLC_MASK GENMASK(3, 0)
> > +#define ACC_DLC_RTR_FLAG BIT(4)
> > +#define ACC_DLC_TXD_FLAG BIT(5)
> > +
> > +/* ecc value of esdACC equals SJA1000's ECC register */
> > +#define ACC_ECC_SEG 0x1f
> > +#define ACC_ECC_DIR 0x20
> > +#define ACC_ECC_BIT 0x00
> > +#define ACC_ECC_FORM 0x40
> > +#define ACC_ECC_STUFF 0x80
> > +#define ACC_ECC_MASK 0xc0
> > +
> > +/* esdACC Status Register bits. Unused bits not documented. */
> > +#define ACC_REG_STATUS_MASK_STATUS_ES BIT(17)
> > +#define ACC_REG_STATUS_MASK_STATUS_EP BIT(18)
> > +#define ACC_REG_STATUS_MASK_STATUS_BS BIT(19)
> > +
> > +/* esdACC Overview Module BM_IRQ_Mask register related defines */
> > +/* Two bit wide command masks to mask or unmask a single core IRQ */
> > +#define ACC_BM_IRQ_UNMASK BIT(0)
> > +#define ACC_BM_IRQ_MASK (ACC_BM_IRQ_UNMASK << 1)
> > +/* Command to unmask all IRQ sources. Created by shifting
> > + * and oring the two bit wide ACC_BM_IRQ_UNMASK 16 times.
> > + */
> > +#define ACC_BM_IRQ_UNMASK_ALL 0x55555555U
> > +
> > +static void acc_resetmode_enter(struct acc_core *core)
> > +{
> > + acc_set_bits(core, ACC_CORE_OF_CTRL_MODE,
> > + ACC_REG_CONTROL_MASK_MODE_RESETMODE);
> > +
> > + /* Read back reset mode bit to flush PCI write posting */
> > + acc_resetmode_entered(core);
> > +}
> > +
> > +static void acc_resetmode_leave(struct acc_core *core)
> > +{
> > + acc_clear_bits(core, ACC_CORE_OF_CTRL_MODE,
> > + ACC_REG_CONTROL_MASK_MODE_RESETMODE);
> > +
> > + /* Read back reset mode bit to flush PCI write posting */
> > + acc_resetmode_entered(core);
> > +}
> > +
> > +static void acc_txq_put(struct acc_core *core, u32 acc_id, u8 acc_dlc,
> > + const void *data)
> > +{
> > + acc_write32_noswap(core, ACC_CORE_OF_TXFIFO_DATA_1,
> > + *((const u32 *)(data + 4)));
> > + acc_write32_noswap(core, ACC_CORE_OF_TXFIFO_DATA_0,
> > + *((const u32 *)data));
> > + acc_write32(core, ACC_CORE_OF_TXFIFO_DLC, acc_dlc);
> > + /* CAN id must be written at last. This write starts TX. */
> > + acc_write32(core, ACC_CORE_OF_TXFIFO_ID, acc_id);
> > +}
> > +
> > +static u8 acc_tx_fifo_next(struct acc_core *core, u8 tx_fifo_idx)
> > +{
> > + ++tx_fifo_idx;
> > + if (tx_fifo_idx >= core->tx_fifo_size)
> > + tx_fifo_idx = 0U;
> > + return tx_fifo_idx;
> > +}
> > +/* Convert timestamp from esdACC time stamp ticks to ns
> > + *
> > + * The conversion factor ts2ns from time stamp counts to ns is basically
> > + * ts2ns = NSEC_PER_SEC / timestamp_frequency
> > + *
> > + * We handle here only a fixed timestamp frequency of 80MHz. The
> > + * resulting ts2ns factor would be 12.5.
> > + *
> > + * At the end we multiply by 12 and add the half of the HW timestamp
> > + * to get a multiplication by 12.5. This way any overflow is
> > + * avoided until ktime_t itself overflows.
> > + */
> > +#define ACC_TS_FACTOR (NSEC_PER_SEC / ACC_TS_FREQ_80MHZ)
> > +#define ACC_TS_80MHZ_SHIFT 1
> > +
> > +static ktime_t acc_ts2ktime(struct acc_ov *ov, u64 ts)
> > +{
> > + u64 ns;
> > +
> > + ns = (ts * ACC_TS_FACTOR) + (ts >> ACC_TS_80MHZ_SHIFT);
> > +
> > + return ns_to_ktime(ns);
> > +}
>
> Nitpick: if the macro is meant to have a global scope, better to put
> it at the beginning with other macros. If the scope is only
> acc_ts2ktime(), then undefine them once it is out of scope.
>
> #undef ACC_TS_FACTOR
> #undef ACC_TS_80MHZ_SHIFT
This should really have only local scope. So I will #undef them
here ...
> > +void acc_init_ov(struct acc_ov *ov, struct device *dev)
> > +{
> > + u32 temp;
> > +
> > + temp = acc_ov_read32(ov, ACC_OV_OF_VERSION);
> > + ov->version = temp;
> > + ov->features = (temp >> 16);
> > +
> > + temp = acc_ov_read32(ov, ACC_OV_OF_INFO);
> > + ov->total_cores = temp;
> > + ov->active_cores = (temp >> 8);
> > +
> > + ov->core_frequency = acc_ov_read32(ov, ACC_OV_OF_CANCORE_FREQ);
> > + ov->timestamp_frequency = acc_ov_read32(ov, ACC_OV_OF_TS_FREQ_LO);
> > +
> > + /* Depending on esdACC feature NEW_PSC enable the new prescaler
> > + * or adjust core_frequency according to the implicit division by 2.
> > + */
> > + if (ov->features & ACC_OV_REG_FEAT_MASK_NEW_PSC) {
> > + acc_ov_set_bits(ov, ACC_OV_OF_MODE,
> > + ACC_OV_REG_MODE_MASK_NEW_PSC_ENABLE);
> > + } else {
> > + ov->core_frequency /= 2;
> > + }
> > +
> > + dev_dbg(dev,
> > + "esdACC v%u, freq: %u/%u, feat/strap: 0x%x/0x%x, cores: %u/%u\n",
> > + ov->version, ov->core_frequency, ov->timestamp_frequency,
> > + ov->features, acc_ov_read32(ov, ACC_OV_OF_INFO) >> 16,
> > + ov->active_cores, ov->total_cores);
> > +}
> > +
> > +void acc_init_bm_ptr(struct acc_ov *ov, struct acc_core *cores, const void *mem)
> > +{
> > + unsigned int u;
> > +
> > + /* DMA buffer layout as follows where N is the number of CAN cores
> > + * implemented in the FPGA, i.e. N = ov->total_cores
> > + *
> > + * Section Layout Section size
> > + * ----------------------------------------------
> > + * FIFO Card/Overview ACC_CORE_DMABUF_SIZE
> > + * FIFO Core0 ACC_CORE_DMABUF_SIZE
> > + * ... ...
> > + * FIFO CoreN ACC_CORE_DMABUF_SIZE
> > + * irq_cnt Card/Overview sizeof(u32)
> > + * irq_cnt Core0 sizeof(u32)
> > + * ... ...
> > + * irq_cnt CoreN sizeof(u32)
> > + */
> > + ov->bmfifo.messages = mem;
> > + ov->bmfifo.irq_cnt = mem + (ov->total_cores + 1U) * ACC_CORE_DMABUF_SIZE;
> > +
> > + for (u = 0U; u < ov->active_cores; u++) {
> > + struct acc_core *core = &cores[u];
> > +
> > + core->bmfifo.messages = mem + (u + 1U) * ACC_CORE_DMABUF_SIZE;
> > + core->bmfifo.irq_cnt = ov->bmfifo.irq_cnt + (u + 1U);
> > + }
> > +}
> > +
> > +int acc_open(struct net_device *netdev)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > + struct acc_core *core = priv->core;
> > + u32 tx_fifo_status;
> > + u32 ctrl_mode;
> > + int err;
> > +
> > + /* Retry to enter RESET mode if out of sync. */
> > + if (priv->can.state != CAN_STATE_STOPPED) {
> > + netdev_warn(netdev, "Entered %s() with bad can.state: %s\n",
> > + __func__, can_get_state_str(priv->can.state));
> > + acc_resetmode_enter(core);
> > + priv->can.state = CAN_STATE_STOPPED;
> > + }
> > +
> > + err = open_candev(netdev);
> > + if (err)
> > + return err;
> > +
> > + ctrl_mode = ACC_REG_CONTROL_MASK_IE_RXTX |
> > + ACC_REG_CONTROL_MASK_IE_TXERROR |
> > + ACC_REG_CONTROL_MASK_IE_ERRWARN |
> > + ACC_REG_CONTROL_MASK_IE_OVERRUN |
> > + ACC_REG_CONTROL_MASK_IE_ERRPASS;
> > +
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
> > + ctrl_mode |= ACC_REG_CONTROL_MASK_IE_BUSERR;
> > +
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> > + ctrl_mode |= ACC_REG_CONTROL_MASK_MODE_LOM;
> > +
> > + acc_set_bits(core, ACC_CORE_OF_CTRL_MODE, ctrl_mode);
> > +
> > + acc_resetmode_leave(core);
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > +
> > + /* Resync TX FIFO indices to HW state after (re-)start. */
> > + tx_fifo_status = acc_read32(core, ACC_CORE_OF_TXFIFO_STATUS);
> > + core->tx_fifo_head = tx_fifo_status & 0xff;
> > + core->tx_fifo_tail = (tx_fifo_status >> 8) & 0xff;
> > +
> > + netif_start_queue(netdev);
> > + return 0;
> > +}
> > +
> > +int acc_close(struct net_device *netdev)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > + struct acc_core *core = priv->core;
> > +
> > + acc_clear_bits(core, ACC_CORE_OF_CTRL_MODE,
> > + ACC_REG_CONTROL_MASK_IE_RXTX |
> > + ACC_REG_CONTROL_MASK_IE_TXERROR |
> > + ACC_REG_CONTROL_MASK_IE_ERRWARN |
> > + ACC_REG_CONTROL_MASK_IE_OVERRUN |
> > + ACC_REG_CONTROL_MASK_IE_ERRPASS |
> > + ACC_REG_CONTROL_MASK_IE_BUSERR);
> > +
> > + netif_stop_queue(netdev);
> > + acc_resetmode_enter(core);
> > + priv->can.state = CAN_STATE_STOPPED;
> > +
> > + /* Mark pending TX requests to be aborted after controller restart. */
> > + acc_write32(core, ACC_CORE_OF_TX_ABORT_MASK, 0xffff);
> > +
> > + /* ACC_REG_CONTROL_MASK_MODE_LOM is only accessible in RESET mode */
> > + acc_clear_bits(core, ACC_CORE_OF_CTRL_MODE,
> > + ACC_REG_CONTROL_MASK_MODE_LOM);
> > +
> > + close_candev(netdev);
> > + return 0;
> > +}
> > +
> > +netdev_tx_t acc_start_xmit(struct sk_buff *skb, struct net_device *netdev)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > + struct acc_core *core = priv->core;
> > + struct can_frame *cf = (struct can_frame *)skb->data;
> > + u8 tx_fifo_head = core->tx_fifo_head;
> > + int fifo_usage;
> > + u32 acc_id;
> > + u8 acc_dlc;
> > +
> > + if (can_dropped_invalid_skb(netdev, skb))
> > + return NETDEV_TX_OK;
> > +
> > + /* Access core->tx_fifo_tail only once because it may be changed
> > + * from the interrupt level.
> > + */
> > + fifo_usage = tx_fifo_head - core->tx_fifo_tail;
> > + if (fifo_usage < 0)
> > + fifo_usage += core->tx_fifo_size;
> > +
> > + if (fifo_usage >= core->tx_fifo_size - 1) {
> > + netdev_err(core->netdev,
> > + "BUG: TX ring full when queue awake!\n");
> > + netif_stop_queue(netdev);
> > + return NETDEV_TX_BUSY;
> > + }
> > +
> > + if (fifo_usage == core->tx_fifo_size - 2)
> > + netif_stop_queue(netdev);
> > +
> > + acc_dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
> > + if (cf->can_id & CAN_RTR_FLAG)
> > + acc_dlc |= ACC_DLC_RTR_FLAG;
> > +
> > + if (cf->can_id & CAN_EFF_FLAG) {
> > + acc_id = cf->can_id & CAN_EFF_MASK;
> > + acc_id |= ACC_ID_EFF_FLAG;
> > + } else {
> > + acc_id = cf->can_id & CAN_SFF_MASK;
> > + }
> > +
> > + can_put_echo_skb(skb, netdev, core->tx_fifo_head, 0);
> > +
> > + core->tx_fifo_head = acc_tx_fifo_next(core, tx_fifo_head);
> > +
> > + acc_txq_put(core, acc_id, acc_dlc, cf->data);
> > +
> > + return NETDEV_TX_OK;
> > +}
> > +
> > +int acc_get_berr_counter(const struct net_device *netdev,
> > + struct can_berr_counter *bec)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > + u32 core_status = acc_read32(priv->core, ACC_CORE_OF_STATUS);
> > +
> > + bec->txerr = (core_status >> 8) & 0xff;
> > + bec->rxerr = core_status & 0xff;
> > +
> > + return 0;
> > +}
> > +
> > +int acc_set_mode(struct net_device *netdev, enum can_mode mode)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > +
> > + switch (mode) {
> > + case CAN_MODE_START:
> > + /* Paranoid FIFO index check. */
> > + {
> > + const u32 tx_fifo_status =
> > + acc_read32(priv->core, ACC_CORE_OF_TXFIFO_STATUS);
> > + const u8 hw_fifo_head = tx_fifo_status;
> > +
> > + if (hw_fifo_head != priv->core->tx_fifo_head ||
> > + hw_fifo_head != priv->core->tx_fifo_tail) {
> > + netdev_warn(netdev,
> > + "TX FIFO mismatch: T %2u H %2u; TFHW %#08x\n",
> > + priv->core->tx_fifo_tail,
> > + priv->core->tx_fifo_head,
> > + tx_fifo_status);
> > + }
> > + }
> > + acc_resetmode_leave(priv->core);
> > + /* To leave the bus-off state the esdACC controller begins
> > + * here a grace period where it counts 128 "idle conditions" (each
> > + * of 11 consecutive recessive bits) on the bus as required
> > + * by the CAN spec.
> > + *
> > + * During this time the TX FIFO may still contain already
> > + * aborted "zombie" frames that are only drained from the FIFO
> > + * at the end of the grace period.
> > + *
> > + * To not to interfere with this drain process we don't
> > + * call netif_wake_queue() here. When the controller reaches
> > + * the error-active state again, it informs us about that
> > + * with an acc_bmmsg_errstatechange message. Then
> > + * netif_wake_queue() is called from
> > + * handle_core_msg_errstatechange() instead.
> > + */
> > + break;
> > +
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int acc_set_bittiming(struct net_device *netdev)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(netdev);
> > + const struct can_bittiming *bt = &priv->can.bittiming;
> > + u32 brp;
> > + u32 btr;
> > +
> > + if (priv->ov->features & ACC_OV_REG_FEAT_MASK_CANFD) {
> > + u32 fbtr = 0;
> > +
> > + netdev_dbg(netdev, "bit timing: brp %u, prop %u, ph1 %u ph2 %u, sjw %u\n",
> > + bt->brp, bt->prop_seg,
> > + bt->phase_seg1, bt->phase_seg2, bt->sjw);
> > +
> > + brp = FIELD_PREP(ACC_REG_BRP_FD_MASK_BRP, bt->brp - 1);
> > +
> > + btr = FIELD_PREP(ACC_REG_BTR_FD_MASK_TSEG1, bt->phase_seg1 + bt->prop_seg - 1);
> > + btr |= FIELD_PREP(ACC_REG_BTR_FD_MASK_TSEG2, bt->phase_seg2 - 1);
> > + btr |= FIELD_PREP(ACC_REG_BTR_FD_MASK_SJW, bt->sjw - 1);
> > +
> > + /* Keep order of accesses to ACC_CORE_OF_BRP and ACC_CORE_OF_BTR. */
> > + acc_write32(priv->core, ACC_CORE_OF_BRP, brp);
> > + acc_write32(priv->core, ACC_CORE_OF_BTR, btr);
> > +
> > + netdev_dbg(netdev, "esdACC: BRP %u, NBTR 0x%08x, DBTR 0x%08x",
> > + brp, btr, fbtr);
> > + } else {
> > + netdev_dbg(netdev, "bit timing: brp %u, prop %u, ph1 %u ph2 %u, sjw %u\n",
> > + bt->brp, bt->prop_seg,
> > + bt->phase_seg1, bt->phase_seg2, bt->sjw);
> > +
> > + brp = FIELD_PREP(ACC_REG_BRP_CL_MASK_BRP, bt->brp - 1);
> > +
> > + btr = FIELD_PREP(ACC_REG_BTR_CL_MASK_TSEG1, bt->phase_seg1 + bt->prop_seg - 1);
> > + btr |= FIELD_PREP(ACC_REG_BTR_CL_MASK_TSEG2, bt->phase_seg2 - 1);
> > + btr |= FIELD_PREP(ACC_REG_BTR_CL_MASK_SJW, bt->sjw - 1);
> > +
> > + /* Keep order of accesses to ACC_CORE_OF_BRP and ACC_CORE_OF_BTR. */
> > + acc_write32(priv->core, ACC_CORE_OF_BRP, brp);
> > + acc_write32(priv->core, ACC_CORE_OF_BTR, btr);
> > +
> > + netdev_dbg(netdev, "esdACC: BRP %u, BTR 0x%08x", brp, btr);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void handle_core_msg_rxtxdone(struct acc_core *core,
> > + const struct acc_bmmsg_rxtxdone *msg)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(core->netdev);
> > + struct net_device_stats *stats = &core->netdev->stats;
> > + struct sk_buff *skb;
> > +
> > + if (msg->acc_dlc.len & ACC_DLC_TXD_FLAG) {
> > + u8 tx_fifo_tail = core->tx_fifo_tail;
> > +
> > + if (core->tx_fifo_head == tx_fifo_tail) {
> > + netdev_warn(core->netdev,
> > + "TX interrupt, but queue is empty!?\n");
> > + return;
> > + }
> > +
> > + /* Direct access echo skb to attach HW time stamp. */
> > + skb = priv->can.echo_skb[tx_fifo_tail];
> > + if (skb) {
> > + skb_hwtstamps(skb)->hwtstamp =
> > + acc_ts2ktime(priv->ov, msg->ts);
> > + }
> > +
> > + stats->tx_packets++;
> > + stats->tx_bytes += can_get_echo_skb(core->netdev, tx_fifo_tail,
> > + NULL);
> > +
> > + core->tx_fifo_tail = acc_tx_fifo_next(core, tx_fifo_tail);
> > +
> > + netif_wake_queue(core->netdev);
> > +
> > + } else {
> > + struct can_frame *cf;
> > +
> > + skb = alloc_can_skb(core->netdev, &cf);
> > + if (!skb) {
> > + stats->rx_dropped++;
> > + return;
> > + }
> > +
> > + cf->can_id = msg->id & ACC_ID_ID_MASK;
> > + if (msg->id & ACC_ID_EFF_FLAG)
> > + cf->can_id |= CAN_EFF_FLAG;
> > +
> > + can_frame_set_cc_len(cf, msg->acc_dlc.len & ACC_DLC_DLC_MASK,
> > + priv->can.ctrlmode);
> > +
> > + if (msg->acc_dlc.len & ACC_DLC_RTR_FLAG) {
> > + cf->can_id |= CAN_RTR_FLAG;
> > + } else {
> > + memcpy(cf->data, msg->data, cf->len);
> > + stats->rx_bytes += cf->len;
> > + }
> > + stats->rx_packets++;
> > +
> > + skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
> > +
> > + netif_rx(skb);
> > + }
> > +}
> > +
> > +static void handle_core_msg_txabort(struct acc_core *core,
> > + const struct acc_bmmsg_txabort *msg)
> > +{
> > + struct net_device_stats *stats = &core->netdev->stats;
> > + u8 tx_fifo_tail = core->tx_fifo_tail;
> > + u32 abort_mask = msg->abort_mask; /* u32 extend to avoid warnings later */
> > +
> > + /* The abort_mask shows which frames were aborted in esdACC's FIFO. */
> > + while (tx_fifo_tail != core->tx_fifo_head && (abort_mask)) {
> > + const u32 tail_mask = (1U << tx_fifo_tail);
> > +
> > + if (!(abort_mask & tail_mask))
> > + break;
> > + abort_mask &= ~tail_mask;
> > +
> > + can_free_echo_skb(core->netdev, tx_fifo_tail, NULL);
> > + stats->tx_dropped++;
> > + stats->tx_aborted_errors++;
> > +
> > + tx_fifo_tail = acc_tx_fifo_next(core, tx_fifo_tail);
> > + }
> > + core->tx_fifo_tail = tx_fifo_tail;
> > + if (abort_mask)
> > + netdev_warn(core->netdev, "Unhandled aborted messages\n");
> > +
> > + if (!acc_resetmode_entered(core))
> > + netif_wake_queue(core->netdev);
> > +}
> > +
> > +static void handle_core_msg_overrun(struct acc_core *core,
> > + const struct acc_bmmsg_overrun *msg)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(core->netdev);
> > + struct net_device_stats *stats = &core->netdev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > +
> > + /* lost_cnt may be 0 if not supported by esdACC version */
> > + if (msg->lost_cnt) {
> > + stats->rx_errors += msg->lost_cnt;
> > + stats->rx_over_errors += msg->lost_cnt;
> > + } else {
> > + stats->rx_errors++;
> > + stats->rx_over_errors++;
> > + }
> > +
> > + skb = alloc_can_err_skb(core->netdev, &cf);
> > + if (!skb)
> > + return;
> > +
> > + cf->can_id |= CAN_ERR_CRTL;
> > + cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> > +
> > + skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
> > +
> > + netif_rx(skb);
> > +}
> > +
> > +static void handle_core_msg_buserr(struct acc_core *core,
> > + const struct acc_bmmsg_buserr *msg)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(core->netdev);
> > + struct net_device_stats *stats = &core->netdev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > + const u32 reg_status = msg->reg_status;
> > + const u8 rxerr = reg_status;
> > + const u8 txerr = (reg_status >> 8);
> > + u8 can_err_prot_type = 0U;
> > +
> > + priv->can.can_stats.bus_error++;
> > +
> > + /* Error occurred during transmission? */
> > + if (msg->ecc & ACC_ECC_DIR) {
> > + stats->rx_errors++;
> > + } else {
> > + can_err_prot_type |= CAN_ERR_PROT_TX;
> > + stats->tx_errors++;
> > + }
> > + /* Determine error type */
> > + switch (msg->ecc & ACC_ECC_MASK) {
> > + case ACC_ECC_BIT:
> > + can_err_prot_type |= CAN_ERR_PROT_BIT;
> > + break;
> > + case ACC_ECC_FORM:
> > + can_err_prot_type |= CAN_ERR_PROT_FORM;
> > + break;
> > + case ACC_ECC_STUFF:
> > + can_err_prot_type |= CAN_ERR_PROT_STUFF;
> > + break;
> > + default:
> > + can_err_prot_type |= CAN_ERR_PROT_UNSPEC;
> > + break;
> > + }
> > +
> > + skb = alloc_can_err_skb(core->netdev, &cf);
> > + if (!skb)
> > + return;
> > +
> > + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR | CAN_ERR_CNT;
> > +
> > + /* Set protocol error type */
> > + cf->data[2] = can_err_prot_type;
> > + /* Set error location */
> > + cf->data[3] = msg->ecc & ACC_ECC_SEG;
> > +
> > + /* Insert CAN TX and RX error counters. */
> > + cf->data[6] = txerr;
> > + cf->data[7] = rxerr;
> > +
> > + skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
> > +
> > + netif_rx(skb);
> > +}
> > +
> > +static void
> > +handle_core_msg_errstatechange(struct acc_core *core,
> > + const struct acc_bmmsg_errstatechange *msg)
> > +{
> > + struct acc_net_priv *priv = netdev_priv(core->netdev);
> > + struct can_frame *cf = NULL;
> > + struct sk_buff *skb;
> > + const u32 reg_status = msg->reg_status;
> > + const u8 rxerr = reg_status;
> > + const u8 txerr = (reg_status >> 8);
> > + enum can_state new_state;
> > +
> > + if (reg_status & ACC_REG_STATUS_MASK_STATUS_BS) {
> > + new_state = CAN_STATE_BUS_OFF;
> > + } else if (reg_status & ACC_REG_STATUS_MASK_STATUS_EP) {
> > + new_state = CAN_STATE_ERROR_PASSIVE;
> > + } else if (reg_status & ACC_REG_STATUS_MASK_STATUS_ES) {
> > + new_state = CAN_STATE_ERROR_WARNING;
> > + } else {
> > + new_state = CAN_STATE_ERROR_ACTIVE;
> > + if (priv->can.state == CAN_STATE_BUS_OFF) {
> > + /* See comment in acc_set_mode() for CAN_MODE_START */
> > + netif_wake_queue(core->netdev);
> > + }
> > + }
> > +
> > + skb = alloc_can_err_skb(core->netdev, &cf);
> > +
> > + if (new_state != priv->can.state) {
> > + enum can_state tx_state, rx_state;
> > +
> > + tx_state = (txerr >= rxerr) ?
> > + new_state : CAN_STATE_ERROR_ACTIVE;
> > + rx_state = (rxerr >= txerr) ?
> > + new_state : CAN_STATE_ERROR_ACTIVE;
> > +
> > + /* Always call can_change_state() to update the state
> > + * even if alloc_can_err_skb() may have failed.
> > + * can_change_state() can cope with a NULL cf pointer.
> > + */
> > + can_change_state(core->netdev, cf, tx_state, rx_state);
> > + }
> > +
> > + if (skb) {
> > + cf->can_id |= CAN_ERR_CNT;
> > + cf->data[6] = txerr;
> > + cf->data[7] = rxerr;
> > +
> > + skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
> > +
> > + netif_rx(skb);
> > + }
> > +
> > + if (new_state == CAN_STATE_BUS_OFF) {
> > + acc_write32(core, ACC_CORE_OF_TX_ABORT_MASK, 0xffff);
> > + can_bus_off(core->netdev);
> > + }
> > +}
> > +
> > +static void handle_core_interrupt(struct acc_core *core)
> > +{
> > + u32 msg_fifo_head = core->bmfifo.local_irq_cnt & 0xff;
> > +
> > + while (core->bmfifo.msg_fifo_tail != msg_fifo_head) {
> > + const union acc_bmmsg *msg =
> > + &core->bmfifo.messages[core->bmfifo.msg_fifo_tail];
> > +
> > + switch (msg->msg_id) {
> > + case BM_MSG_ID_RXTXDONE:
> > + handle_core_msg_rxtxdone(core, &msg->rxtxdone);
> > + break;
> > +
> > + case BM_MSG_ID_TXABORT:
> > + handle_core_msg_txabort(core, &msg->txabort);
> > + break;
> > +
> > + case BM_MSG_ID_OVERRUN:
> > + handle_core_msg_overrun(core, &msg->overrun);
> > + break;
> > +
> > + case BM_MSG_ID_BUSERR:
> > + handle_core_msg_buserr(core, &msg->buserr);
> > + break;
> > +
> > + case BM_MSG_ID_ERRPASSIVE:
> > + case BM_MSG_ID_ERRWARN:
> > + handle_core_msg_errstatechange(core,
> > + &msg->errstatechange);
> > + break;
> > +
> > + default:
> > + /* Ignore all other BM messages (like the CAN-FD messages) */
> > + break;
> > + }
> > +
> > + core->bmfifo.msg_fifo_tail =
> > + (core->bmfifo.msg_fifo_tail + 1) & 0xff;
> > + }
> > +}
> > +
> > +/**
> > + * acc_card_interrupt() - handle the interrupts of an esdACC FPGA
> > + *
> > + * @ov: overview module structure
> > + * @cores: array of core structures
> > + *
> > + * This function handles all interrupts pending for the overview module and the
> > + * CAN cores of the esdACC FPGA.
> > + *
> > + * It examines for all cores (the overview module core and the CAN cores)
> > + * the bmfifo.irq_cnt and compares it with the previously saved
> > + * bmfifo.local_irq_cnt. An IRQ is pending if they differ. The esdACC FPGA
> > + * updates the bmfifo.irq_cnt values by DMA.
> > + *
> > + * The pending interrupts are masked by writing to the IRQ mask register at
> > + * ACC_OV_OF_BM_IRQ_MASK. This register has for each core a two bit command
> > + * field evaluated as follows:
> > + *
> > + * Define, bit pattern: meaning
> > + * 00: no action
> > + * ACC_BM_IRQ_UNMASK, 01: unmask interrupt
> > + * ACC_BM_IRQ_MASK, 10: mask interrupt
> > + * 11: no action
>
> Nitpick: consider this format
>
> * Define bit pattern meaning
> * ------------------------------------------------------
> * 00 no action
> * ACC_BM_IRQ_UNMASK 01 unmask interrupt
> * ACC_BM_IRQ_MASK 10 mask interrupt
> * 11 no action
>
> (I am using spaces due to a limitation of my email client, you can use
> tab instead)
>
> > + * For each CAN core with a pending IRQ handle_core_interrupt() handles all
> > + * busmaster messages from the message FIFO. The last handled message (FIFO
> > + * index) is written to the CAN core to acknowledge its handling.
> > + *
> > + * Last step is to unmask all interrupts in the FPGA using
> > + * ACC_BM_IRQ_UNMASK_ALL.
> > + *
> > + * Return:
> > + * IRQ_HANDLED, if card generated an interrupt that was handled
> > + * IRQ_NONE, if the interrupt is not ours
> > + */
> > +irqreturn_t acc_card_interrupt(struct acc_ov *ov, struct acc_core *cores)
> > +{
> > + u32 irqmask;
> > + int i;
> > +
> > + /* First we look for whom interrupts are pending, card/overview
> > + * or any of the cores. Two bits in irqmask are used for each;
> > + * Each two bit field is set to ACC_BM_IRQ_MASK if an IRQ is
> > + * pending.
> > + */
> > + irqmask = 0U;
> > + if (READ_ONCE(*ov->bmfifo.irq_cnt) != ov->bmfifo.local_irq_cnt) {
> > + irqmask |= ACC_BM_IRQ_MASK;
> > + ov->bmfifo.local_irq_cnt = READ_ONCE(*ov->bmfifo.irq_cnt);
> > + }
> > +
> > + for (i = 0; i < ov->active_cores; i++) {
> > + struct acc_core *core = &cores[i];
> > +
> > + if (READ_ONCE(*core->bmfifo.irq_cnt) != core->bmfifo.local_irq_cnt) {
> > + irqmask |= (ACC_BM_IRQ_MASK << (2 * (i + 1)));
> > + core->bmfifo.local_irq_cnt = READ_ONCE(*core->bmfifo.irq_cnt);
> > + }
> > + }
> > +
> > + if (!irqmask)
> > + return IRQ_NONE;
> > +
> > + /* At second we tell the card we're working on them by writing irqmask,
> > + * call handle_{ov|core}_interrupt and then acknowledge the
> > + * interrupts by writing irq_cnt:
> > + */
> > + acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_MASK, irqmask);
> > +
> > + if (irqmask & ACC_BM_IRQ_MASK) {
> > + /* handle_ov_interrupt(); - no use yet. */
> > + acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_COUNTER,
> > + ov->bmfifo.local_irq_cnt);
> > + }
> > +
> > + for (i = 0; i < ov->active_cores; i++) {
> > + struct acc_core *core = &cores[i];
> > +
> > + if (irqmask & (ACC_BM_IRQ_MASK << (2 * (i + 1)))) {
> > + handle_core_interrupt(core);
> > + acc_write32(core, ACC_OV_OF_BM_IRQ_COUNTER,
> > + core->bmfifo.local_irq_cnt);
> > + }
> > + }
> > +
> > + acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_MASK, ACC_BM_IRQ_UNMASK_ALL);
> > +
> > + return IRQ_HANDLED;
> > +}
>
> (...)
>
> Yours sincerely,
> Vincent Mailhol