--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+//
+// bxcan.c - STM32 Basic Extended CAN controller driver
+//
+// Copyright (c) 2022 Dario Binacchi <dario.binacchi@amarulasolutions.com>
+//
+// NOTE: The ST documentation uses the terms master/slave instead of
+// primary/secondary.
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitfield.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/rx-offload.h>
+#include <linux/clk.h>
+#include <linux/ethtool.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define BXCAN_NAPI_WEIGHT 3
+#define BXCAN_TIMEOUT_US 10000
+
+#define BXCAN_RX_MB_NUM 2
+#define BXCAN_TX_MB_NUM 3
+
+/* Primary control register (MCR) bits */
+#define BXCAN_MCR_RESET BIT(15)
+#define BXCAN_MCR_TTCM BIT(7)
+#define BXCAN_MCR_ABOM BIT(6)
+#define BXCAN_MCR_AWUM BIT(5)
+#define BXCAN_MCR_NART BIT(4)
+#define BXCAN_MCR_RFLM BIT(3)
+#define BXCAN_MCR_TXFP BIT(2)
+#define BXCAN_MCR_SLEEP BIT(1)
+#define BXCAN_MCR_INRQ BIT(0)
+
+/* Primary status register (MSR) bits */
+#define BXCAN_MSR_ERRI BIT(2)
+#define BXCAN_MSR_SLAK BIT(1)
+#define BXCAN_MSR_INAK BIT(0)
+
+/* Transmit status register (TSR) bits */
+#define BXCAN_TSR_RQCP2 BIT(16)
+#define BXCAN_TSR_RQCP1 BIT(8)
+#define BXCAN_TSR_RQCP0 BIT(0)
+
+/* Receive FIFO 0 register (RF0R) bits */
+#define BXCAN_RF0R_RFOM0 BIT(5)
+#define BXCAN_RF0R_FMP0_MASK GENMASK(1, 0)
+
+/* Interrupt enable register (IER) bits */
+#define BXCAN_IER_SLKIE BIT(17)
+#define BXCAN_IER_WKUIE BIT(16)
+#define BXCAN_IER_ERRIE BIT(15)
+#define BXCAN_IER_LECIE BIT(11)
+#define BXCAN_IER_BOFIE BIT(10)
+#define BXCAN_IER_EPVIE BIT(9)
+#define BXCAN_IER_EWGIE BIT(8)
+#define BXCAN_IER_FOVIE1 BIT(6)
+#define BXCAN_IER_FFIE1 BIT(5)
+#define BXCAN_IER_FMPIE1 BIT(4)
+#define BXCAN_IER_FOVIE0 BIT(3)
+#define BXCAN_IER_FFIE0 BIT(2)
+#define BXCAN_IER_FMPIE0 BIT(1)
+#define BXCAN_IER_TMEIE BIT(0)
+
+/* Error status register (ESR) bits */
+#define BXCAN_ESR_REC_MASK GENMASK(31, 24)
+#define BXCAN_ESR_TEC_MASK GENMASK(23, 16)
+#define BXCAN_ESR_LEC_MASK GENMASK(6, 4)
+#define BXCAN_ESR_BOFF BIT(2)
+#define BXCAN_ESR_EPVF BIT(1)
+#define BXCAN_ESR_EWGF BIT(0)
+
+/* Bit timing register (BTR) bits */
+#define BXCAN_BTR_SILM BIT(31)
+#define BXCAN_BTR_LBKM BIT(30)
+#define BXCAN_BTR_SJW_MASK GENMASK(25, 24)
+#define BXCAN_BTR_TS2_MASK GENMASK(22, 20)
+#define BXCAN_BTR_TS1_MASK GENMASK(19, 16)
+#define BXCAN_BTR_BRP_MASK GENMASK(9, 0)
+
+/* TX mailbox identifier register (TIxR, x = 0..2) bits */
+#define BXCAN_TIxR_STID_MASK GENMASK(31, 21)
+#define BXCAN_TIxR_EXID_MASK GENMASK(31, 3)
+#define BXCAN_TIxR_IDE BIT(2)
+#define BXCAN_TIxR_RTR BIT(1)
+#define BXCAN_TIxR_TXRQ BIT(0)
+
+/* TX mailbox data length and time stamp register (TDTxR, x = 0..2 bits */
+#define BXCAN_TDTxR_DLC_MASK GENMASK(3, 0)
+
+/* RX FIFO mailbox identifier register (RIxR, x = 0..1 */
+#define BXCAN_RIxR_STID_MASK GENMASK(31, 21)
+#define BXCAN_RIxR_EXID_MASK GENMASK(31, 3)
+#define BXCAN_RIxR_IDE BIT(2)
+#define BXCAN_RIxR_RTR BIT(1)
+
+/* RX FIFO mailbox data length and timestamp register (RDTxR, x = 0..1) bits */
+#define BXCAN_RDTxR_TIME_MASK GENMASK(31, 16)
+#define BXCAN_RDTxR_DLC_MASK GENMASK(3, 0)
+
+#define BXCAN_FMR_REG 0x00
+#define BXCAN_FM1R_REG 0x04
+#define BXCAN_FS1R_REG 0x0c
+#define BXCAN_FFA1R_REG 0x14
+#define BXCAN_FA1R_REG 0x1c
+#define BXCAN_FiR1_REG(b) (0x40 + (b) * 8)
+#define BXCAN_FiR2_REG(b) (0x44 + (b) * 8)
+
+#define BXCAN_FILTER_ID(primary) (primary ? 0 : 14)
+
+/* Filter primary register (FMR) bits */
+#define BXCAN_FMR_CANSB_MASK GENMASK(13, 8)
+#define BXCAN_FMR_FINIT BIT(0)
+
+enum bxcan_lec_code {
+ BXCAN_LEC_NO_ERROR = 0,
+ BXCAN_LEC_STUFF_ERROR,
+ BXCAN_LEC_FORM_ERROR,
+ BXCAN_LEC_ACK_ERROR,
+ BXCAN_LEC_BIT1_ERROR,
+ BXCAN_LEC_BIT0_ERROR,
+ BXCAN_LEC_CRC_ERROR,
+ BXCAN_LEC_UNUSED
+};
+
+/* Structure of the message buffer */
+struct bxcan_mb {
+ u32 id; /* can identifier */
+ u32 dlc; /* data length control and timestamp */
+ u32 data[2]; /* data */
+};
+
+/* Structure of the hardware registers */
+struct bxcan_regs {
+ u32 mcr; /* 0x00 - primary control */
+ u32 msr; /* 0x04 - primary status */
+ u32 tsr; /* 0x08 - transmit status */
+ u32 rf0r; /* 0x0c - FIFO 0 */
+ u32 rf1r; /* 0x10 - FIFO 1 */
+ u32 ier; /* 0x14 - interrupt enable */
+ u32 esr; /* 0x18 - error status */
+ u32 btr; /* 0x1c - bit timing*/
+ u32 reserved0[88]; /* 0x20 */
+ struct bxcan_mb tx_mb[BXCAN_TX_MB_NUM]; /* 0x180 - tx mailbox */
+ struct bxcan_mb rx_mb[BXCAN_RX_MB_NUM]; /* 0x1b0 - rx mailbox */
+};
+
+struct bxcan_priv {
+ struct can_priv can;
+ struct can_rx_offload offload;
+ struct device *dev;
+ struct net_device *ndev;
+
+ struct bxcan_regs __iomem *regs;
+ struct regmap *gcan;
+ int tx_irq;
+ int sce_irq;
+ bool primary;
+ struct clk *clk;
+ spinlock_t rmw_lock; /* lock for read-modify-write operations */
+ unsigned int tx_head;
+ unsigned int tx_tail;
+ u32 timestamp;
+};
+
+static const struct can_bittiming_const bxcan_bittiming_const = {
+ .name = KBUILD_MODNAME,
+ .tseg1_min = 1,
+ .tseg1_max = 16,
+ .tseg2_min = 1,
+ .tseg2_max = 8,
+ .sjw_max = 4,
+ .brp_min = 1,
+ .brp_max = 1024,
+ .brp_inc = 1,
+};
+
+static inline void bxcan_rmw(struct bxcan_priv *priv, void __iomem *addr,
+ u32 clear, u32 set)
+{
+ unsigned long flags;
+ u32 old, val;
+
+ spin_lock_irqsave(&priv->rmw_lock, flags);
+ old = readl(addr);
+ val = (old & ~clear) | set;
+ if (val != old)
+ writel(val, addr);
+
+ spin_unlock_irqrestore(&priv->rmw_lock, flags);
+}
+
+static void bxcan_disable_filters(struct bxcan_priv *priv, bool primary)
+{
+ unsigned int fid = BXCAN_FILTER_ID(primary);
+ u32 fmask = BIT(fid);
+
+ regmap_update_bits(priv->gcan, BXCAN_FA1R_REG, fmask, 0);
+}
+
+static void bxcan_enable_filters(struct bxcan_priv *priv, bool primary)
+{
+ unsigned int fid = BXCAN_FILTER_ID(primary);
+ u32 fmask = BIT(fid);
+
+ /* Filter settings:
+ *
+ * Accept all messages.
+ * Assign filter 0 to CAN1 and filter 14 to CAN2 in identifier
+ * mask mode with 32 bits width.
+ */
+
+ /* Enter filter initialization mode and assing filters to CAN
+ * controllers.
+ */
+ regmap_update_bits(priv->gcan, BXCAN_FMR_REG,
+ BXCAN_FMR_CANSB_MASK | BXCAN_FMR_FINIT,
+ FIELD_PREP(BXCAN_FMR_CANSB_MASK, 14) |
+ BXCAN_FMR_FINIT);
+
+ /* Deactivate filter */
+ regmap_update_bits(priv->gcan, BXCAN_FA1R_REG, fmask, 0);
+
+ /* Two 32-bit registers in identifier mask mode */
+ regmap_update_bits(priv->gcan, BXCAN_FM1R_REG, fmask, 0);
+
+ /* Single 32-bit scale configuration */
+ regmap_update_bits(priv->gcan, BXCAN_FS1R_REG, fmask, fmask);
+
+ /* Assign filter to FIFO 0 */
+ regmap_update_bits(priv->gcan, BXCAN_FFA1R_REG, fmask, 0);
+
+ /* Accept all messages */
+ regmap_write(priv->gcan, BXCAN_FiR1_REG(fid), 0);
+ regmap_write(priv->gcan, BXCAN_FiR2_REG(fid), 0);
+
+ /* Activate filter */
+ regmap_update_bits(priv->gcan, BXCAN_FA1R_REG, fmask, fmask);
+
+ /* Exit filter initialization mode */
+ regmap_update_bits(priv->gcan, BXCAN_FMR_REG, BXCAN_FMR_FINIT, 0);
+}
+
+static inline u8 bxcan_get_tx_head(const struct bxcan_priv *priv)
+{
+ return priv->tx_head % BXCAN_TX_MB_NUM;
+}
+
+static inline u8 bxcan_get_tx_tail(const struct bxcan_priv *priv)
+{
+ return priv->tx_tail % BXCAN_TX_MB_NUM;
+}
+
+static inline u8 bxcan_get_tx_free(const struct bxcan_priv *priv)
+{
+ return BXCAN_TX_MB_NUM - (priv->tx_head - priv->tx_tail);
+}
+
+static bool bxcan_tx_busy(const struct bxcan_priv *priv)
+{
+ if (bxcan_get_tx_free(priv) > 0)
+ return false;
+
+ netif_stop_queue(priv->ndev);
+
+ /* Memory barrier before checking tx_free (head and tail) */
+ smp_mb();
+
+ if (bxcan_get_tx_free(priv) == 0) {
+ netdev_dbg(priv->ndev,
+ "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n",
+ priv->tx_head, priv->tx_tail,
+ priv->tx_head - priv->tx_tail);
+
+ return true;
+ }
+
+ netif_start_queue(priv->ndev);
+
+ return false;
+}
+
+static int bxcan_chip_softreset(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 value;
+
+ bxcan_rmw(priv, ®s->mcr, 0, BXCAN_MCR_RESET);
+ return readx_poll_timeout(readl, ®s->msr, value,
+ value & BXCAN_MSR_SLAK, BXCAN_TIMEOUT_US,
+ USEC_PER_SEC);
+}
+
+static int bxcan_enter_init_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 value;
+
+ bxcan_rmw(priv, ®s->mcr, 0, BXCAN_MCR_INRQ);
+ return readx_poll_timeout(readl, ®s->msr, value,
+ value & BXCAN_MSR_INAK, BXCAN_TIMEOUT_US,
+ USEC_PER_SEC);
+}
+
+static int bxcan_leave_init_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 value;
+
+ bxcan_rmw(priv, ®s->mcr, BXCAN_MCR_INRQ, 0);
+ return readx_poll_timeout(readl, ®s->msr, value,
+ !(value & BXCAN_MSR_INAK), BXCAN_TIMEOUT_US,
+ USEC_PER_SEC);
+}
+
+static int bxcan_enter_sleep_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 value;
+
+ bxcan_rmw(priv, ®s->mcr, 0, BXCAN_MCR_SLEEP);
+ return readx_poll_timeout(readl, ®s->msr, value,
+ value & BXCAN_MSR_SLAK, BXCAN_TIMEOUT_US,
+ USEC_PER_SEC);
+}
+
+static int bxcan_leave_sleep_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 value;
+
+ bxcan_rmw(priv, ®s->mcr, BXCAN_MCR_SLEEP, 0);
+ return readx_poll_timeout(readl, ®s->msr, value,
+ !(value & BXCAN_MSR_SLAK), BXCAN_TIMEOUT_US,
+ USEC_PER_SEC);
+}
+
+static inline
+struct bxcan_priv *rx_offload_to_priv(struct can_rx_offload *offload)
+{
+ return container_of(offload, struct bxcan_priv, offload);
+}
+
+static struct sk_buff *bxcan_mailbox_read(struct can_rx_offload *offload,
+ unsigned int mbxno, u32 *timestamp,
+ bool drop)
+{
+ struct bxcan_priv *priv = rx_offload_to_priv(offload);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct bxcan_mb __iomem *mb_regs = ®s->rx_mb[0];
+ struct sk_buff *skb = NULL;
+ struct can_frame *cf;
+ u32 rf0r, id, dlc;
+
+ rf0r = readl(®s->rf0r);
+ if (unlikely(drop)) {
+ skb = ERR_PTR(-ENOBUFS);
+ goto mark_as_read;
+ }
+
+ if (!(rf0r & BXCAN_RF0R_FMP0_MASK))
+ goto mark_as_read;
+
+ skb = alloc_can_skb(offload->dev, &cf);
+ if (unlikely(!skb)) {
+ skb = ERR_PTR(-ENOMEM);
+ goto mark_as_read;
+ }
+
+ id = readl(&mb_regs->id);
+ if (id & BXCAN_RIxR_IDE)
+ cf->can_id = FIELD_GET(BXCAN_RIxR_EXID_MASK, id) | CAN_EFF_FLAG;
+ else
+ cf->can_id = FIELD_GET(BXCAN_RIxR_STID_MASK, id) & CAN_SFF_MASK;
+
+ dlc = readl(&mb_regs->dlc);
+ priv->timestamp = FIELD_GET(BXCAN_RDTxR_TIME_MASK, dlc);
+ cf->len = can_cc_dlc2len(FIELD_GET(BXCAN_RDTxR_DLC_MASK, dlc));
+
+ if (id & BXCAN_RIxR_RTR) {
+ cf->can_id |= CAN_RTR_FLAG;
+ } else {
+ int i, j;
+
+ for (i = 0, j = 0; i < cf->len; i += 4, j++)
+ *(u32 *)(cf->data + i) = readl(&mb_regs->data[j]);
+ }
+
+ mark_as_read:
+ rf0r |= BXCAN_RF0R_RFOM0;
+ writel(rf0r, ®s->rf0r);
+ return skb;
+}
+
+static irqreturn_t bxcan_rx_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 rf0r;
+
+ rf0r = readl(®s->rf0r);
+ if (!(rf0r & BXCAN_RF0R_FMP0_MASK))
+ return IRQ_NONE;
+
+ can_rx_offload_irq_offload_fifo(&priv->offload);
+ can_rx_offload_irq_finish(&priv->offload);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t bxcan_tx_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct net_device_stats *stats = &ndev->stats;
+ u32 tsr, rqcp_bit;
+ int idx;
+
+ tsr = readl(®s->tsr);
+ if (!(tsr & (BXCAN_TSR_RQCP0 | BXCAN_TSR_RQCP1 | BXCAN_TSR_RQCP2)))
+ return IRQ_NONE;
+
+ while (priv->tx_head - priv->tx_tail > 0) {
+ idx = bxcan_get_tx_tail(priv);
+ rqcp_bit = BXCAN_TSR_RQCP0 << (idx << 3);
+ if (!(tsr & rqcp_bit))
+ break;
+
+ stats->tx_packets++;
+ stats->tx_bytes += can_get_echo_skb(ndev, idx, NULL);
+ priv->tx_tail++;
+ }
+
+ writel(tsr, ®s->tsr);
+
+ if (bxcan_get_tx_free(priv)) {
+ /* Make sure that anybody stopping the queue after
+ * this sees the new tx_ring->tail.
+ */
+ smp_mb();
+ netif_wake_queue(ndev);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void bxcan_handle_state_change(struct net_device *ndev, u32 esr)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ enum can_state new_state = priv->can.state;
+ struct can_berr_counter bec;
+ enum can_state rx_state, tx_state;
+ struct sk_buff *skb;
+ struct can_frame *cf;
+
+ /* Early exit if no error flag is set */
+ if (!(esr & (BXCAN_ESR_EWGF | BXCAN_ESR_EPVF | BXCAN_ESR_BOFF)))
+ return;
+
+ bec.txerr = FIELD_GET(BXCAN_ESR_TEC_MASK, esr);
+ bec.rxerr = FIELD_GET(BXCAN_ESR_REC_MASK, esr);
+
+ if (esr & BXCAN_ESR_BOFF)
+ new_state = CAN_STATE_BUS_OFF;
+ else if (esr & BXCAN_ESR_EPVF)
+ new_state = CAN_STATE_ERROR_PASSIVE;
+ else if (esr & BXCAN_ESR_EWGF)
+ new_state = CAN_STATE_ERROR_WARNING;
+
+ /* state hasn't changed */
+ if (unlikely(new_state == priv->can.state))
+ return;
+
+ skb = alloc_can_err_skb(ndev, &cf);
+
+ tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
+ rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
+ can_change_state(ndev, cf, tx_state, rx_state);
+
+ if (new_state == CAN_STATE_BUS_OFF) {
+ can_bus_off(ndev);
+ } else if (skb) {
+ cf->can_id |= CAN_ERR_CNT;
+ cf->data[6] = bec.txerr;
+ cf->data[7] = bec.rxerr;
+ }
+
+ if (skb) {
+ int err;
+
+ err = can_rx_offload_queue_timestamp(&priv->offload, skb,
+ priv->timestamp);
+ if (err)
+ ndev->stats.rx_fifo_errors++;
+ }
+}
+
+static void bxcan_handle_bus_err(struct net_device *ndev, u32 esr)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ enum bxcan_lec_code lec_code;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+
+ lec_code = FIELD_GET(BXCAN_ESR_LEC_MASK, esr);
+
+ /* Early exit if no lec update or no error.
+ * No lec update means that no CAN bus event has been detected
+ * since CPU wrote BXCAN_LEC_UNUSED value to status reg.
+ */
+ if (lec_code == BXCAN_LEC_UNUSED || lec_code == BXCAN_LEC_NO_ERROR)
+ return;
+
+ /* Common for all type of bus errors */
+ priv->can.can_stats.bus_error++;
+
+ /* Propagate the error condition to the CAN stack */
+ skb = alloc_can_err_skb(ndev, &cf);
+ if (skb)
+ cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+ switch (lec_code) {
+ case BXCAN_LEC_STUFF_ERROR:
+ netdev_dbg(ndev, "Stuff error\n");
+ ndev->stats.rx_errors++;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_STUFF;
+ break;
+
+ case BXCAN_LEC_FORM_ERROR:
+ netdev_dbg(ndev, "Form error\n");
+ ndev->stats.rx_errors++;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_FORM;
+ break;
+
+ case BXCAN_LEC_ACK_ERROR:
+ netdev_dbg(ndev, "Ack error\n");
+ ndev->stats.tx_errors++;
+ if (skb) {
+ cf->can_id |= CAN_ERR_ACK;
+ cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+ }
+ break;
+
+ case BXCAN_LEC_BIT1_ERROR:
+ netdev_dbg(ndev, "Bit error (recessive)\n");
+ ndev->stats.tx_errors++;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_BIT1;
+ break;
+
+ case BXCAN_LEC_BIT0_ERROR:
+ netdev_dbg(ndev, "Bit error (dominant)\n");
+ ndev->stats.tx_errors++;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_BIT0;
+ break;
+
+ case BXCAN_LEC_CRC_ERROR:
+ netdev_dbg(ndev, "CRC error\n");
+ ndev->stats.rx_errors++;
+ if (skb) {
+ cf->data[2] |= CAN_ERR_PROT_BIT;
+ cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ if (skb) {
+ int err;
+
+ err = can_rx_offload_queue_timestamp(&priv->offload, skb,
+ priv->timestamp);
+ if (err)
+ ndev->stats.rx_fifo_errors++;
+ }
+}
+
+static irqreturn_t bxcan_state_change_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 msr, esr;
+
+ msr = readl(®s->msr);
+ if (!(msr & BXCAN_MSR_ERRI))
+ return IRQ_NONE;
+
+ esr = readl(®s->esr);
+ bxcan_handle_state_change(ndev, esr);
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+ bxcan_handle_bus_err(ndev, esr);
+
+ msr |= BXCAN_MSR_ERRI;
+ writel(msr, ®s->msr);
+ can_rx_offload_irq_finish(&priv->offload);
+
+ return IRQ_HANDLED;
+}
+
+static int bxcan_chip_start(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct can_bittiming *bt = &priv->can.bittiming;
+ u32 clr, set;
+ int err;
+
+ err = bxcan_chip_softreset(priv);
+ if (err) {
+ netdev_err(ndev, "failed to reset chip, error %pe\n",
+ ERR_PTR(err));
+ return err;
+ }
+
+ err = bxcan_leave_sleep_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to leave sleep mode, error %pe\n",
+ ERR_PTR(err));
+ goto failed_leave_sleep;
+ }
+
+ err = bxcan_enter_init_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to enter init mode, error %pe\n",
+ ERR_PTR(err));
+ goto failed_enter_init;
+ }
+
+ /* MCR
+ *
+ * select request order priority
+ * enable time triggered mode
+ * bus-off state left on sw request
+ * sleep mode left on sw request
+ * retransmit automatically on error
+ * do not lock RX FIFO on overrun
+ */
+ bxcan_rmw(priv, ®s->mcr,
+ BXCAN_MCR_ABOM | BXCAN_MCR_AWUM | BXCAN_MCR_NART |
+ BXCAN_MCR_RFLM, BXCAN_MCR_TTCM | BXCAN_MCR_TXFP);
+
+ /* Bit timing register settings */
+ set = FIELD_PREP(BXCAN_BTR_BRP_MASK, bt->brp - 1) |
+ FIELD_PREP(BXCAN_BTR_TS1_MASK, bt->phase_seg1 +
+ bt->prop_seg - 1) |
+ FIELD_PREP(BXCAN_BTR_TS2_MASK, bt->phase_seg2 - 1) |
+ FIELD_PREP(BXCAN_BTR_SJW_MASK, bt->sjw - 1);
+
+ /* loopback + silent mode put the controller in test mode,
+ * useful for hot self-test
+ */
+ if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+ set |= BXCAN_BTR_LBKM;
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+ set |= BXCAN_BTR_SILM;
+
+ bxcan_rmw(priv, ®s->btr, BXCAN_BTR_SILM | BXCAN_BTR_LBKM |
+ BXCAN_BTR_BRP_MASK | BXCAN_BTR_TS1_MASK | BXCAN_BTR_TS2_MASK |
+ BXCAN_BTR_SJW_MASK, set);
+
+ bxcan_enable_filters(priv, priv->primary);
+
+ /* Clear all internal status */
+ priv->tx_head = 0;
+ priv->tx_tail = 0;
+
+ err = bxcan_leave_init_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to leave init mode, error %pe\n",
+ ERR_PTR(err));
+ goto failed_leave_init;
+ }
+
+ /* Set a `lec` value so that we can check for updates later */
+ bxcan_rmw(priv, ®s->esr, BXCAN_ESR_LEC_MASK,
+ FIELD_PREP(BXCAN_ESR_LEC_MASK, BXCAN_LEC_UNUSED));
+
+ /* IER
+ *
+ * Enable interrupt for:
+ * bus-off
+ * passive error
+ * warning error
+ * last error code
+ * RX FIFO pending message
+ * TX mailbox empty
+ */
+ clr = BXCAN_IER_WKUIE | BXCAN_IER_SLKIE | BXCAN_IER_FOVIE1 |
+ BXCAN_IER_FFIE1 | BXCAN_IER_FMPIE1 | BXCAN_IER_FOVIE0 |
+ BXCAN_IER_FFIE0;
+ set = BXCAN_IER_ERRIE | BXCAN_IER_BOFIE | BXCAN_IER_EPVIE |
+ BXCAN_IER_EWGIE | BXCAN_IER_FMPIE0 | BXCAN_IER_TMEIE;
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+ set |= BXCAN_IER_LECIE;
+ else
+ clr |= BXCAN_IER_LECIE;
+
+ bxcan_rmw(priv, ®s->ier, clr, set);
+
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+ return 0;
+
+failed_leave_init:
+failed_enter_init:
+failed_leave_sleep:
+ bxcan_chip_softreset(priv);
+ return err;
+}
+
+static int bxcan_open(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ int err;
+
+ err = clk_prepare_enable(priv->clk);
+ if (err) {
+ netdev_err(ndev, "failed to enable clock, error %pe\n",
+ ERR_PTR(err));
+ return err;
+ }
+
+ err = open_candev(ndev);
+ if (err) {
+ netdev_err(ndev, "open_candev() failed, error %pe\n",
+ ERR_PTR(err));
+ goto out_disable_clock;
+ }
+
+ can_rx_offload_enable(&priv->offload);
+ err = request_irq(ndev->irq, bxcan_rx_isr, IRQF_SHARED, ndev->name,
+ ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register rx irq(%d), error %pe\n",
+ ndev->irq, ERR_PTR(err));
+ goto out_close_candev;
+ }
+
+ err = request_irq(priv->tx_irq, bxcan_tx_isr, IRQF_SHARED, ndev->name,
+ ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register tx irq(%d), error %pe\n",
+ priv->tx_irq, ERR_PTR(err));
+ goto out_free_rx_irq;
+ }
+
+ err = request_irq(priv->sce_irq, bxcan_state_change_isr, IRQF_SHARED,
+ ndev->name, ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register sce irq(%d), error %pe\n",
+ priv->sce_irq, ERR_PTR(err));
+ goto out_free_tx_irq;
+ }
+
+ err = bxcan_chip_start(ndev);
+ if (err)
+ goto out_free_sce_irq;
+
+ netif_start_queue(ndev);
+ return 0;
+
+out_free_sce_irq:
+ free_irq(priv->sce_irq, ndev);
+out_free_tx_irq:
+ free_irq(priv->tx_irq, ndev);
+out_free_rx_irq:
+ free_irq(ndev->irq, ndev);
+out_close_candev:
+ can_rx_offload_disable(&priv->offload);
+ close_candev(ndev);
+out_disable_clock:
+ clk_disable_unprepare(priv->clk);
+ return err;
+}
+
+static void bxcan_chip_stop(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+
+ /* disable all interrupts */
+ bxcan_rmw(priv, ®s->ier, BXCAN_IER_SLKIE | BXCAN_IER_WKUIE |
+ BXCAN_IER_ERRIE | BXCAN_IER_LECIE | BXCAN_IER_BOFIE |
+ BXCAN_IER_EPVIE | BXCAN_IER_EWGIE | BXCAN_IER_FOVIE1 |
+ BXCAN_IER_FFIE1 | BXCAN_IER_FMPIE1 | BXCAN_IER_FOVIE0 |
+ BXCAN_IER_FFIE0 | BXCAN_IER_FMPIE0 | BXCAN_IER_TMEIE, 0);
+ bxcan_disable_filters(priv, priv->primary);
+ bxcan_enter_sleep_mode(priv);
+ priv->can.state = CAN_STATE_STOPPED;
+}
+
+static int bxcan_stop(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ netif_stop_queue(ndev);
+ bxcan_chip_stop(ndev);
+ free_irq(ndev->irq, ndev);
+ free_irq(priv->tx_irq, ndev);
+ free_irq(priv->sce_irq, ndev);
+ can_rx_offload_disable(&priv->offload);
+ close_candev(ndev);
+ clk_disable_unprepare(priv->clk);
+ return 0;
+}
+
+static netdev_tx_t bxcan_start_xmit(struct sk_buff *skb,
+ struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct can_frame *cf = (struct can_frame *)skb->data;
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct bxcan_mb __iomem *mb_regs;
+ unsigned int idx;
+ u32 id;
+ int i, j;
+
+ if (can_dropped_invalid_skb(ndev, skb))
+ return NETDEV_TX_OK;
+
+ if (bxcan_tx_busy(priv))
+ return NETDEV_TX_BUSY;
+
+ idx = bxcan_get_tx_head(priv);
+ priv->tx_head++;
+ if (bxcan_get_tx_free(priv) == 0)
+ netif_stop_queue(ndev);
+
+ mb_regs = ®s->tx_mb[idx];
+ if (cf->can_id & CAN_EFF_FLAG)
+ id = FIELD_PREP(BXCAN_TIxR_EXID_MASK, cf->can_id) |
+ BXCAN_TIxR_IDE;
+ else
+ id = FIELD_PREP(BXCAN_TIxR_STID_MASK, cf->can_id);
+
+ if (cf->can_id & CAN_RTR_FLAG) { /* Remote transmission request */
+ id |= BXCAN_TIxR_RTR;
+ } else {
+ for (i = 0, j = 0; i < cf->len; i += 4, j++)
+ writel(*(u32 *)(cf->data + i), &mb_regs->data[j]);
+ }
+
+ writel(FIELD_PREP(BXCAN_TDTxR_DLC_MASK, cf->len), &mb_regs->dlc);
+
+ can_put_echo_skb(skb, ndev, idx, 0);
+
+ /* Start transmission */
+ writel(id | BXCAN_TIxR_TXRQ, &mb_regs->id);
+
+ return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops bxcan_netdev_ops = {
+ .ndo_open = bxcan_open,
+ .ndo_stop = bxcan_stop,
+ .ndo_start_xmit = bxcan_start_xmit,
+ .ndo_change_mtu = can_change_mtu,
+};
+
+static const struct ethtool_ops bxcan_ethtool_ops = {
+ .get_ts_info = ethtool_op_get_ts_info,
+};
+
+static int bxcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+ int err;
+
+ switch (mode) {
+ case CAN_MODE_START:
+ err = bxcan_chip_start(ndev);
+ if (err)
+ return err;
+
+ netif_wake_queue(ndev);
+ break;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static int bxcan_get_berr_counter(const struct net_device *ndev,
+ struct can_berr_counter *bec)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 esr;
+ int err;
+
+ err = clk_prepare_enable(priv->clk);
+ if (err)
+ return err;
+
+ esr = readl(®s->esr);
+ bec->txerr = FIELD_GET(BXCAN_ESR_TEC_MASK, esr);
+ bec->rxerr = FIELD_GET(BXCAN_ESR_REC_MASK, esr);
+ clk_disable_unprepare(priv->clk);
+ return 0;
+}
+
+static int bxcan_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device *dev = &pdev->dev;
+ struct net_device *ndev;
+ struct bxcan_priv *priv;
+ struct clk *clk = NULL;
+ void __iomem *regs;
+ struct regmap *gcan;
+ bool primary;
+ int err, rx_irq, tx_irq, sce_irq;
+
+ regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(regs)) {
+ dev_err(dev, "failed to get base address\n");
+ return PTR_ERR(regs);
+ }
+
+ gcan = syscon_regmap_lookup_by_phandle(np, "st,gcan");
+ if (IS_ERR(gcan)) {
+ dev_err(dev, "failed to get shared memory base address\n");
+ return PTR_ERR(gcan);
+ }
+
+ primary = of_property_read_bool(np, "st,can-primary");
+ clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(dev, "failed to get clock\n");
+ return PTR_ERR(clk);
+ }
+
+ rx_irq = platform_get_irq_byname(pdev, "rx0");
+ if (rx_irq < 0) {
+ dev_err(dev, "failed to get rx0 irq\n");
+ return rx_irq;
+ }
+
+ tx_irq = platform_get_irq_byname(pdev, "tx");
+ if (tx_irq < 0) {
+ dev_err(dev, "failed to get tx irq\n");
+ return tx_irq;
+ }
+
+ sce_irq = platform_get_irq_byname(pdev, "sce");
+ if (sce_irq < 0) {
+ dev_err(dev, "failed to get sce irq\n");
+ return sce_irq;
+ }
+
+ ndev = alloc_candev(sizeof(struct bxcan_priv), BXCAN_TX_MB_NUM);
+ if (!ndev) {
+ dev_err(dev, "alloc_candev() failed\n");
+ return -ENOMEM;
+ }
+
+ priv = netdev_priv(ndev);
+ platform_set_drvdata(pdev, ndev);
+ SET_NETDEV_DEV(ndev, dev);
+ ndev->netdev_ops = &bxcan_netdev_ops;
+ ndev->ethtool_ops = &bxcan_ethtool_ops;
+ ndev->irq = rx_irq;
+ ndev->flags |= IFF_ECHO;
+
+ priv->dev = dev;
+ priv->ndev = ndev;
+ priv->regs = regs;
+ priv->gcan = gcan;
+ priv->clk = clk;
+ priv->tx_irq = tx_irq;
+ priv->sce_irq = sce_irq;
+ priv->primary = primary;
+ priv->can.clock.freq = clk_get_rate(clk);
+ spin_lock_init(&priv->rmw_lock);
+ priv->tx_head = 0;
+ priv->tx_tail = 0;
+ priv->can.bittiming_const = &bxcan_bittiming_const;
+ priv->can.do_set_mode = bxcan_do_set_mode;
+ priv->can.do_get_berr_counter = bxcan_get_berr_counter;
+ priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
+ CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING;
+
+ priv->offload.mailbox_read = bxcan_mailbox_read;
+ err = can_rx_offload_add_fifo(ndev, &priv->offload, BXCAN_NAPI_WEIGHT);
+ if (err) {
+ dev_err(dev, "failed to add FIFO rx_offload\n");
+ goto out_free_candev;
+ }
+
+ err = register_candev(ndev);
+ if (err) {
+ dev_err(dev, "failed to register netdev\n");
+ goto out_can_rx_offload_del;
+ }
+
+ dev_info(dev, "clk: %d Hz, IRQs: %d, %d, %d\n", priv->can.clock.freq,
+ tx_irq, rx_irq, sce_irq);
+ return 0;
+
+out_can_rx_offload_del:
+ can_rx_offload_del(&priv->offload);
+out_free_candev:
+ free_candev(ndev);
+ return err;
+}
+
+static int bxcan_remove(struct platform_device *pdev)
+{
+ struct net_device *ndev = platform_get_drvdata(pdev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ unregister_candev(ndev);
+ clk_disable_unprepare(priv->clk);
+ can_rx_offload_del(&priv->offload);
+ free_candev(ndev);
+ return 0;
+}
+
+static int __maybe_unused bxcan_suspend(struct device *dev)
+{
+ struct net_device *ndev = dev_get_drvdata(dev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ if (!netif_running(ndev))
+ return 0;
+
+ netif_stop_queue(ndev);
+ netif_device_detach(ndev);
+
+ bxcan_enter_sleep_mode(priv);
+ priv->can.state = CAN_STATE_SLEEPING;
+ clk_disable_unprepare(priv->clk);
+ return 0;
+}
+
+static int __maybe_unused bxcan_resume(struct device *dev)
+{
+ struct net_device *ndev = dev_get_drvdata(dev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ if (!netif_running(ndev))
+ return 0;
+
+ clk_prepare_enable(priv->clk);
+ bxcan_leave_sleep_mode(priv);
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+ netif_device_attach(ndev);
+ netif_start_queue(ndev);
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(bxcan_pm_ops, bxcan_suspend, bxcan_resume);
+
+static const struct of_device_id bxcan_of_match[] = {
+ {.compatible = "st,stm32f4-bxcan"},
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, bxcan_of_match);
+
+static struct platform_driver bxcan_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .pm = &bxcan_pm_ops,
+ .of_match_table = bxcan_of_match,
+ },
+ .probe = bxcan_probe,
+ .remove = bxcan_remove,
+};
+
+module_platform_driver(bxcan_driver);
+
+MODULE_AUTHOR("Dario Binacchi <dario.binacchi@amarulasolutions.com>");
+MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN controller driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-starfive.git / commitdiff