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can: xilinx_can: Add support for CANFD FD frames
authorAppana Durga Kedareswara rao <appana.durga.rao@xilinx.com>
Mon, 18 Mar 2019 11:32:44 +0000 (17:02 +0530)
committerMarc Kleine-Budde <mkl@pengutronix.de>
Wed, 24 Jul 2019 08:31:54 +0000 (10:31 +0200)
CANFD IP supports both CAN and CAN FD frames,
Existing driver supports only CAN frames, This patch
adds support for CAN FD frames.

Signed-off-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Signed-off-by: Appana Durga Kedareswara rao <appana.durga.rao@xilinx.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
drivers/net/can/xilinx_can.c

index e76418c..fadd541 100644 (file)
@@ -50,6 +50,10 @@ enum xcan_reg {
        XCAN_AFR_OFFSET         = 0x60, /* Acceptance Filter */
 
        /* only on CAN FD cores */
+       XCAN_F_BRPR_OFFSET      = 0x088, /* Data Phase Baud Rate
+                                         * Prescalar
+                                         */
+       XCAN_F_BTR_OFFSET       = 0x08C, /* Data Phase Bit Timing */
        XCAN_TRR_OFFSET         = 0x0090, /* TX Buffer Ready Request */
        XCAN_AFR_EXT_OFFSET     = 0x00E0, /* Acceptance Filter */
        XCAN_FSR_OFFSET         = 0x00E8, /* RX FIFO Status */
@@ -62,6 +66,8 @@ enum xcan_reg {
 #define XCAN_FRAME_DLC_OFFSET(frame_base)      ((frame_base) + 0x04)
 #define XCAN_FRAME_DW1_OFFSET(frame_base)      ((frame_base) + 0x08)
 #define XCAN_FRAME_DW2_OFFSET(frame_base)      ((frame_base) + 0x0C)
+#define XCANFD_FRAME_DW_OFFSET(frame_base, n)  (((frame_base) + 0x08) + \
+                                                ((n) * XCAN_CANFD_FRAME_SIZE))
 
 #define XCAN_CANFD_FRAME_SIZE          0x48
 #define XCAN_TXMSG_FRAME_OFFSET(n)     (XCAN_TXMSG_BASE_OFFSET + \
@@ -120,6 +126,8 @@ enum xcan_reg {
 #define XCAN_FSR_FL_MASK               0x00003F00 /* RX Fill Level */
 #define XCAN_FSR_IRI_MASK              0x00000080 /* RX Increment Read Index */
 #define XCAN_FSR_RI_MASK               0x0000001F /* RX Read Index */
+#define XCAN_DLCR_EDL_MASK             0x08000000 /* EDL Mask in DLC */
+#define XCAN_DLCR_BRS_MASK             0x04000000 /* BRS Mask in DLC */
 
 /* CAN register bit shift - XCAN_<REG>_<BIT>_SHIFT */
 #define XCAN_BTR_SJW_SHIFT             7  /* Synchronous jump width */
@@ -133,6 +141,7 @@ enum xcan_reg {
 
 /* CAN frame length constants */
 #define XCAN_FRAME_MAX_DATA_LEN                8
+#define XCANFD_DW_BYTES                        4
 #define XCAN_TIMEOUT                   (1 * HZ)
 
 /* TX-FIFO-empty interrupt available */
@@ -213,6 +222,7 @@ static const struct can_bittiming_const xcan_bittiming_const = {
        .brp_inc = 1,
 };
 
+/* AXI CANFD Arbitration Bittiming constants as per AXI CANFD 1.0 spec */
 static const struct can_bittiming_const xcan_bittiming_const_canfd = {
        .name = DRIVER_NAME,
        .tseg1_min = 1,
@@ -225,6 +235,20 @@ static const struct can_bittiming_const xcan_bittiming_const_canfd = {
        .brp_inc = 1,
 };
 
+/* AXI CANFD Data Bittiming constants as per AXI CANFD 1.0 specs */
+static struct can_bittiming_const xcan_data_bittiming_const_canfd = {
+       .name = DRIVER_NAME,
+       .tseg1_min = 1,
+       .tseg1_max = 16,
+       .tseg2_min = 1,
+       .tseg2_max = 8,
+       .sjw_max = 8,
+       .brp_min = 1,
+       .brp_max = 256,
+       .brp_inc = 1,
+};
+
+/* AXI CANFD 2.0 Arbitration Bittiming constants as per AXI CANFD 2.0 spec */
 static const struct can_bittiming_const xcan_bittiming_const_canfd2 = {
        .name = DRIVER_NAME,
        .tseg1_min = 1,
@@ -237,6 +261,19 @@ static const struct can_bittiming_const xcan_bittiming_const_canfd2 = {
        .brp_inc = 1,
 };
 
+/* AXI CANFD 2.0 Data Bittiming constants as per AXI CANFD 2.0 spec */
+static struct can_bittiming_const xcan_data_bittiming_const_canfd2 = {
+       .name = DRIVER_NAME,
+       .tseg1_min = 1,
+       .tseg1_max = 32,
+       .tseg2_min = 1,
+       .tseg2_max = 16,
+       .sjw_max = 16,
+       .brp_min = 1,
+       .brp_max = 256,
+       .brp_inc = 1,
+};
+
 /**
  * xcan_write_reg_le - Write a value to the device register little endian
  * @priv:      Driver private data structure
@@ -351,6 +388,7 @@ static int xcan_set_bittiming(struct net_device *ndev)
 {
        struct xcan_priv *priv = netdev_priv(ndev);
        struct can_bittiming *bt = &priv->can.bittiming;
+       struct can_bittiming *dbt = &priv->can.data_bittiming;
        u32 btr0, btr1;
        u32 is_config_mode;
 
@@ -380,6 +418,24 @@ static int xcan_set_bittiming(struct net_device *ndev)
        priv->write_reg(priv, XCAN_BRPR_OFFSET, btr0);
        priv->write_reg(priv, XCAN_BTR_OFFSET, btr1);
 
+       if (priv->devtype.cantype == XAXI_CANFD ||
+           priv->devtype.cantype == XAXI_CANFD_2_0) {
+               /* Setting Baud Rate prescalar value in F_BRPR Register */
+               btr0 = dbt->brp - 1;
+
+               /* Setting Time Segment 1 in BTR Register */
+               btr1 = dbt->prop_seg + bt->phase_seg1 - 1;
+
+               /* Setting Time Segment 2 in BTR Register */
+               btr1 |= (dbt->phase_seg2 - 1) << priv->devtype.btr_ts2_shift;
+
+               /* Setting Synchronous jump width in BTR Register */
+               btr1 |= (dbt->sjw - 1) << priv->devtype.btr_sjw_shift;
+
+               priv->write_reg(priv, XCAN_F_BRPR_OFFSET, btr0);
+               priv->write_reg(priv, XCAN_F_BTR_OFFSET, btr1);
+       }
+
        netdev_dbg(ndev, "BRPR=0x%08x, BTR=0x%08x\n",
                   priv->read_reg(priv, XCAN_BRPR_OFFSET),
                   priv->read_reg(priv, XCAN_BTR_OFFSET));
@@ -499,7 +555,8 @@ static void xcan_write_frame(struct xcan_priv *priv, struct sk_buff *skb,
                             int frame_offset)
 {
        u32 id, dlc, data[2] = {0, 0};
-       struct can_frame *cf = (struct can_frame *)skb->data;
+       struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+       u32 ramoff, dwindex = 0, i;
 
        /* Watch carefully on the bit sequence */
        if (cf->can_id & CAN_EFF_FLAG) {
@@ -528,26 +585,44 @@ static void xcan_write_frame(struct xcan_priv *priv, struct sk_buff *skb,
                        id |= XCAN_IDR_SRR_MASK;
        }
 
-       dlc = cf->can_dlc << XCAN_DLCR_DLC_SHIFT;
-
-       if (cf->can_dlc > 0)
-               data[0] = be32_to_cpup((__be32 *)(cf->data + 0));
-       if (cf->can_dlc > 4)
-               data[1] = be32_to_cpup((__be32 *)(cf->data + 4));
+       dlc = can_len2dlc(cf->len) << XCAN_DLCR_DLC_SHIFT;
+       if (can_is_canfd_skb(skb)) {
+               if (cf->flags & CANFD_BRS)
+                       dlc |= XCAN_DLCR_BRS_MASK;
+               dlc |= XCAN_DLCR_EDL_MASK;
+       }
 
        priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id);
        /* If the CAN frame is RTR frame this write triggers transmission
         * (not on CAN FD)
         */
        priv->write_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_offset), dlc);
-       if (!(cf->can_id & CAN_RTR_FLAG)) {
-               priv->write_reg(priv, XCAN_FRAME_DW1_OFFSET(frame_offset),
-                               data[0]);
-               /* If the CAN frame is Standard/Extended frame this
-                * write triggers transmission (not on CAN FD)
-                */
-               priv->write_reg(priv, XCAN_FRAME_DW2_OFFSET(frame_offset),
-                               data[1]);
+       if (priv->devtype.cantype == XAXI_CANFD ||
+           priv->devtype.cantype == XAXI_CANFD_2_0) {
+               for (i = 0; i < cf->len; i += 4) {
+                       ramoff = XCANFD_FRAME_DW_OFFSET(frame_offset, dwindex) +
+                                       (dwindex * XCANFD_DW_BYTES);
+                       priv->write_reg(priv, ramoff,
+                                       be32_to_cpup((__be32 *)(cf->data + i)));
+                       dwindex++;
+               }
+       } else {
+               if (cf->len > 0)
+                       data[0] = be32_to_cpup((__be32 *)(cf->data + 0));
+               if (cf->len > 4)
+                       data[1] = be32_to_cpup((__be32 *)(cf->data + 4));
+
+               if (!(cf->can_id & CAN_RTR_FLAG)) {
+                       priv->write_reg(priv,
+                                       XCAN_FRAME_DW1_OFFSET(frame_offset),
+                                       data[0]);
+                       /* If the CAN frame is Standard/Extended frame this
+                        * write triggers transmission (not on CAN FD)
+                        */
+                       priv->write_reg(priv,
+                                       XCAN_FRAME_DW2_OFFSET(frame_offset),
+                                       data[1]);
+               }
        }
 }
 
@@ -725,6 +800,113 @@ static int xcan_rx(struct net_device *ndev, int frame_base)
 }
 
 /**
+ * xcanfd_rx -  Is called from CAN isr to complete the received
+ *             frame  processing
+ * @ndev:      Pointer to net_device structure
+ * @frame_base:        Register offset to the frame to be read
+ *
+ * This function is invoked from the CAN isr(poll) to process the Rx frames. It
+ * does minimal processing and invokes "netif_receive_skb" to complete further
+ * processing.
+ * Return: 1 on success and 0 on failure.
+ */
+static int xcanfd_rx(struct net_device *ndev, int frame_base)
+{
+       struct xcan_priv *priv = netdev_priv(ndev);
+       struct net_device_stats *stats = &ndev->stats;
+       struct canfd_frame *cf;
+       struct sk_buff *skb;
+       u32 id_xcan, dlc, data[2] = {0, 0}, dwindex = 0, i, fsr, readindex;
+
+       fsr = priv->read_reg(priv, XCAN_FSR_OFFSET);
+       if (fsr & XCAN_FSR_FL_MASK) {
+               readindex = fsr & XCAN_FSR_RI_MASK;
+               id_xcan = priv->read_reg(priv,
+                                        XCAN_FRAME_ID_OFFSET(frame_base));
+               dlc = priv->read_reg(priv, XCAN_FRAME_DLC_OFFSET(frame_base));
+               if (dlc & XCAN_DLCR_EDL_MASK)
+                       skb = alloc_canfd_skb(ndev, &cf);
+               else
+                       skb = alloc_can_skb(ndev, (struct can_frame **)&cf);
+
+               if (unlikely(!skb)) {
+                       stats->rx_dropped++;
+                       return 0;
+               }
+
+               /* Change Xilinx CANFD data length format to socketCAN data
+                * format
+                */
+               if (dlc & XCAN_DLCR_EDL_MASK)
+                       cf->len = can_dlc2len((dlc & XCAN_DLCR_DLC_MASK) >>
+                                         XCAN_DLCR_DLC_SHIFT);
+               else
+                       cf->len = get_can_dlc((dlc & XCAN_DLCR_DLC_MASK) >>
+                                                 XCAN_DLCR_DLC_SHIFT);
+
+               /* Change Xilinx CAN ID format to socketCAN ID format */
+               if (id_xcan & XCAN_IDR_IDE_MASK) {
+                       /* The received frame is an Extended format frame */
+                       cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >> 3;
+                       cf->can_id |= (id_xcan & XCAN_IDR_ID2_MASK) >>
+                                       XCAN_IDR_ID2_SHIFT;
+                       cf->can_id |= CAN_EFF_FLAG;
+                       if (id_xcan & XCAN_IDR_RTR_MASK)
+                               cf->can_id |= CAN_RTR_FLAG;
+               } else {
+                       /* The received frame is a standard format frame */
+                       cf->can_id = (id_xcan & XCAN_IDR_ID1_MASK) >>
+                                       XCAN_IDR_ID1_SHIFT;
+                       if (!(dlc & XCAN_DLCR_EDL_MASK) && (id_xcan &
+                                               XCAN_IDR_SRR_MASK))
+                               cf->can_id |= CAN_RTR_FLAG;
+               }
+
+               /* Check the frame received is FD or not*/
+               if (dlc & XCAN_DLCR_EDL_MASK) {
+                       for (i = 0; i < cf->len; i += 4) {
+                               if (priv->devtype.flags & XCAN_FLAG_CANFD_2)
+                                       data[0] = priv->read_reg(priv,
+                                       (XCAN_RXMSG_2_FRAME_OFFSET(readindex) +
+                                       (dwindex * XCANFD_DW_BYTES)));
+                               else
+                                       data[0] = priv->read_reg(priv,
+                                       (XCAN_RXMSG_FRAME_OFFSET(readindex) +
+                                               (dwindex * XCANFD_DW_BYTES)));
+                               *(__be32 *)(cf->data + i) =
+                                               cpu_to_be32(data[0]);
+                               dwindex++;
+                       }
+               } else {
+                       for (i = 0; i < cf->len; i += 4) {
+                               if (priv->devtype.flags & XCAN_FLAG_CANFD_2)
+                                       data[0] = priv->read_reg(priv,
+                                               XCAN_RXMSG_2_FRAME_OFFSET(readindex) + i);
+                               else
+                                       data[0] = priv->read_reg(priv,
+                                               XCAN_RXMSG_FRAME_OFFSET(readindex) + i);
+                               *(__be32 *)(cf->data + i) =
+                                               cpu_to_be32(data[0]);
+                       }
+               }
+               /* Update FSR Register so that next packet will save to
+                * buffer
+                */
+               fsr = priv->read_reg(priv, XCAN_FSR_OFFSET);
+               fsr |= XCAN_FSR_IRI_MASK;
+               priv->write_reg(priv, XCAN_FSR_OFFSET, fsr);
+               fsr = priv->read_reg(priv, XCAN_FSR_OFFSET);
+               stats->rx_bytes += cf->len;
+               stats->rx_packets++;
+               netif_receive_skb(skb);
+
+               return 1;
+       }
+       /* If FSR Register is not updated with fill level */
+       return 0;
+}
+
+/**
  * xcan_current_error_state - Get current error state from HW
  * @ndev:      Pointer to net_device structure
  *
@@ -1035,7 +1217,10 @@ static int xcan_rx_poll(struct napi_struct *napi, int quota)
 
        while ((frame_offset = xcan_rx_fifo_get_next_frame(priv)) >= 0 &&
               (work_done < quota)) {
-               work_done += xcan_rx(ndev, frame_offset);
+               if (xcan_rx_int_mask(priv) & XCAN_IXR_RXOK_MASK)
+                       work_done += xcanfd_rx(ndev, frame_offset);
+               else
+                       work_done += xcan_rx(ndev, frame_offset);
 
                if (priv->devtype.flags & XCAN_FLAG_RX_FIFO_MULTI)
                        /* increment read index */
@@ -1577,6 +1762,19 @@ static int xcan_probe(struct platform_device *pdev)
        priv->can.do_get_berr_counter = xcan_get_berr_counter;
        priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
                                        CAN_CTRLMODE_BERR_REPORTING;
+
+       if (devtype->cantype == XAXI_CANFD)
+               priv->can.data_bittiming_const =
+                       &xcan_data_bittiming_const_canfd;
+
+       if (devtype->cantype == XAXI_CANFD_2_0)
+               priv->can.data_bittiming_const =
+                       &xcan_data_bittiming_const_canfd2;
+
+       if (devtype->cantype == XAXI_CANFD ||
+           devtype->cantype == XAXI_CANFD_2_0)
+               priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
+
        priv->reg_base = addr;
        priv->tx_max = tx_max;
        priv->devtype = *devtype;