[PATCH v8 4/4] can: Allwinner A10/A20 CAN Controller support - Kernel module

Gerhard Bertelsmann
2015-09-16T11:22:26Z

Kernel module for Allwinner A10/A20 CAN

Signed-off-by: Gerhard Bertelsmann <info@gerhard-bertelsmann.de>
---

drivers/net/can/Kconfig | 10 +
drivers/net/can/Makefile | 1 +
drivers/net/can/sun4i_can.c | 857 +++++++++++++++++++++
3 files changed, 868 insertions(+)

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index e8c96b8..6d04183 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -129,6 +129,16 @@ config CAN_RCAR
To compile this driver as a module, choose M here: the module will
be called rcar_can.

+config CAN_SUN4I
+ tristate "Allwinner A10 CAN controller"
+ depends on MACH_SUN4I || MACH_SUN7I || COMPILE_TEST
+ ---help---
+ Say Y here if you want to use CAN controller found on Allwinner
+ A10/A20 SoCs.
+
+ To compile this driver as a module, choose M here: the module will
+ be called sun4i_can.
+
config CAN_XILINXCAN
tristate "Xilinx CAN"
depends on ARCH_ZYNQ || ARM64 || MICROBLAZE || COMPILE_TEST
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c533c62..1f21cef 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_CAN_FLEXCAN) += flexcan.o
obj-$(CONFIG_PCH_CAN) += pch_can.o
obj-$(CONFIG_CAN_GRCAN) += grcan.o
obj-$(CONFIG_CAN_RCAR) += rcar_can.o
+obj-$(CONFIG_CAN_SUN4I) += sun4i_can.o
obj-$(CONFIG_CAN_XILINXCAN) += xilinx_can.o

subdir-ccflags-y += -D__CHECK_ENDIAN__
diff --git a/drivers/net/can/sun4i_can.c b/drivers/net/can/sun4i_can.c
new file mode 100644
index 0000000..10d8497
--- /dev/null
+++ b/drivers/net/can/sun4i_can.c
@@ -0,0 +1,857 @@
+/*
+ * sun4i_can.c - CAN bus controller driver for Allwinner SUN4I&SUN7I based SoCs
+ *
+ * Copyright (C) 2013 Peter Chen
+ * Copyright (C) 2015 Gerhard Bertelsmann
+ * All rights reserved.
+ *
+ * Parts of this software are based on (derived from) the SJA1000 code by:
+ * Copyright (C) 2014 Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
+ * Copyright (C) 2007 Wolfgang Grandegger <wg@grandegger.com>
+ * Copyright (C) 2002-2007 Volkswagen Group Electronic Research
+ * Copyright (C) 2003 Matthias Brukner, Trajet Gmbh, Rebenring 33,
+ * 38106 Braunschweig, GERMANY
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Volkswagen nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * Alternatively, provided that this notice is retained in full, this
+ * software may be distributed under the terms of the GNU General
+ * Public License ("GPL") version 2, in which case the provisions of the
+ * GPL apply INSTEAD OF those given above.
+ *
+ * The provided data structures and external interfaces from this code
+ * are not restricted to be used by modules with a GPL compatible license.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ */
+
+#include <linux/netdevice.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/led.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define DRV_NAME "sun4i_can"
+
+/* Registers address (physical base address 0x01C2BC00) */
+#define SUN4I_REG_MSEL_ADDR 0x0000 /* CAN Mode Select */
+#define SUN4I_REG_CMD_ADDR 0x0004 /* CAN Command */
+#define SUN4I_REG_STA_ADDR 0x0008 /* CAN Status */
+#define SUN4I_REG_INT_ADDR 0x000c /* CAN Interrupt Flag */
+#define SUN4I_REG_INTEN_ADDR 0x0010 /* CAN Interrupt Enable */
+#define SUN4I_REG_BTIME_ADDR 0x0014 /* CAN Bus Timing 0 */
+#define SUN4I_REG_TEWL_ADDR 0x0018 /* CAN Tx Error Warning Limit */
+#define SUN4I_REG_ERRC_ADDR 0x001c /* CAN Error Counter */
+#define SUN4I_REG_RMCNT_ADDR 0x0020 /* CAN Receive Message Counter */
+#define SUN4I_REG_RBUFSA_ADDR 0x0024 /* CAN Receive Buffer Start Address */
+#define SUN4I_REG_BUF0_ADDR 0x0040 /* CAN Tx/Rx Buffer 0 */
+#define SUN4I_REG_BUF1_ADDR 0x0044 /* CAN Tx/Rx Buffer 1 */
+#define SUN4I_REG_BUF2_ADDR 0x0048 /* CAN Tx/Rx Buffer 2 */
+#define SUN4I_REG_BUF3_ADDR 0x004c /* CAN Tx/Rx Buffer 3 */
+#define SUN4I_REG_BUF4_ADDR 0x0050 /* CAN Tx/Rx Buffer 4 */
+#define SUN4I_REG_BUF5_ADDR 0x0054 /* CAN Tx/Rx Buffer 5 */
+#define SUN4I_REG_BUF6_ADDR 0x0058 /* CAN Tx/Rx Buffer 6 */
+#define SUN4I_REG_BUF7_ADDR 0x005c /* CAN Tx/Rx Buffer 7 */
+#define SUN4I_REG_BUF8_ADDR 0x0060 /* CAN Tx/Rx Buffer 8 */
+#define SUN4I_REG_BUF9_ADDR 0x0064 /* CAN Tx/Rx Buffer 9 */
+#define SUN4I_REG_BUF10_ADDR 0x0068 /* CAN Tx/Rx Buffer 10 */
+#define SUN4I_REG_BUF11_ADDR 0x006c /* CAN Tx/Rx Buffer 11 */
+#define SUN4I_REG_BUF12_ADDR 0x0070 /* CAN Tx/Rx Buffer 12 */
+#define SUN4I_REG_ACPC_ADDR 0x0040 /* CAN Acceptance Code 0 */
+#define SUN4I_REG_ACPM_ADDR 0x0044 /* CAN Acceptance Mask 0 */
+#define SUN4I_REG_RBUF_RBACK_START_ADDR 0x0180 /* CAN transmit buffer start */
+#define SUN4I_REG_RBUF_RBACK_END_ADDR 0x01b0 /* CAN transmit buffer end */
+
+/* Controller Register Description */
+
+/* mode select register (r/w)
+ * offset:0x0000 default:0x0000_0001
+ */
+#define SUN4I_MSEL_SLEEP_MODE (0x01 << 4) /* write in reset mode */
+#define SUN4I_MSEL_WAKE_UP (0x00 << 4)
+#define SUN4I_MSEL_SINGLE_FILTER (0x01 << 3) /* write in reset mode */
+#define SUN4I_MSEL_DUAL_FILTERS (0x00 << 3)
+#define SUN4I_MSEL_LOOPBACK_MODE BIT(2)
+#define SUN4I_MSEL_LISTEN_ONLY_MODE BIT(1)
+#define SUN4I_MSEL_RESET_MODE BIT(0)
+
+/* command register (w)
+ * offset:0x0004 default:0x0000_0000
+ */
+#define SUN4I_CMD_BUS_OFF_REQ BIT(5)
+#define SUN4I_CMD_SELF_RCV_REQ BIT(4)
+#define SUN4I_CMD_CLEAR_OR_FLAG BIT(3)
+#define SUN4I_CMD_RELEASE_RBUF BIT(2)
+#define SUN4I_CMD_ABORT_REQ BIT(1)
+#define SUN4I_CMD_TRANS_REQ BIT(0)
+
+/* status register (r)
+ * offset:0x0008 default:0x0000_003c
+ */
+#define SUN4I_STA_BIT_ERR (0x00 << 22)
+#define SUN4I_STA_FORM_ERR (0x01 << 22)
+#define SUN4I_STA_STUFF_ERR (0x02 << 22)
+#define SUN4I_STA_OTHER_ERR (0x03 << 22)
+#define SUN4I_STA_MASK_ERR (0x03 << 22)
+#define SUN4I_STA_ERR_DIR BIT(21)
+#define SUN4I_STA_ERR_SEG_CODE (0x1f << 16)
+#define SUN4I_STA_START (0x03 << 16)
+#define SUN4I_STA_ID28_21 (0x02 << 16)
+#define SUN4I_STA_ID20_18 (0x06 << 16)
+#define SUN4I_STA_SRTR (0x04 << 16)
+#define SUN4I_STA_IDE (0x05 << 16)
+#define SUN4I_STA_ID17_13 (0x07 << 16)
+#define SUN4I_STA_ID12_5 (0x0f << 16)
+#define SUN4I_STA_ID4_0 (0x0e << 16)
+#define SUN4I_STA_RTR (0x0c << 16)
+#define SUN4I_STA_RB1 (0x0d << 16)
+#define SUN4I_STA_RB0 (0x09 << 16)
+#define SUN4I_STA_DLEN (0x0b << 16)
+#define SUN4I_STA_DATA_FIELD (0x0a << 16)
+#define SUN4I_STA_CRC_SEQUENCE (0x08 << 16)
+#define SUN4I_STA_CRC_DELIMITER (0x18 << 16)
+#define SUN4I_STA_ACK (0x19 << 16)
+#define SUN4I_STA_ACK_DELIMITER (0x1b << 16)
+#define SUN4I_STA_END (0x1a << 16)
+#define SUN4I_STA_INTERMISSION (0x12 << 16)
+#define SUN4I_STA_ACTIVE_ERROR (0x11 << 16)
+#define SUN4I_STA_PASSIVE_ERROR (0x16 << 16)
+#define SUN4I_STA_TOLERATE_DOMINANT_BITS (0x13 << 16)
+#define SUN4I_STA_ERROR_DELIMITER (0x17 << 16)
+#define SUN4I_STA_OVERLOAD (0x1c << 16)
+#define SUN4I_STA_BUS_OFF BIT(7)
+#define SUN4I_STA_ERR_STA BIT(6)
+#define SUN4I_STA_TRANS_BUSY BIT(5)
+#define SUN4I_STA_RCV_BUSY BIT(4)
+#define SUN4I_STA_TRANS_OVER BIT(3)
+#define SUN4I_STA_TBUF_RDY BIT(2)
+#define SUN4I_STA_DATA_ORUN BIT(1)
+#define SUN4I_STA_RBUF_RDY BIT(0)
+
+/* interrupt register (r)
+ * offset:0x000c default:0x0000_0000
+ */
+#define SUN4I_INT_BUS_ERR BIT(7)
+#define SUN4I_INT_ARB_LOST BIT(6)
+#define SUN4I_INT_ERR_PASSIVE BIT(5)
+#define SUN4I_INT_WAKEUP BIT(4)
+#define SUN4I_INT_DATA_OR BIT(3)
+#define SUN4I_INT_ERR_WRN BIT(2)
+#define SUN4I_INT_TBUF_VLD BIT(1)
+#define SUN4I_INT_RBUF_VLD BIT(0)
+
+/* interrupt enable register (r/w)
+ * offset:0x0010 default:0x0000_0000
+ */
+#define SUN4I_INTEN_BERR BIT(7)
+#define SUN4I_INTEN_ARB_LOST BIT(6)
+#define SUN4I_INTEN_ERR_PASSIVE BIT(5)
+#define SUN4I_INTEN_WAKEUP BIT(4)
+#define SUN4I_INTEN_OR BIT(3)
+#define SUN4I_INTEN_ERR_WRN BIT(2)
+#define SUN4I_INTEN_TX BIT(1)
+#define SUN4I_INTEN_RX BIT(0)
+
+/* error code */
+#define SUN4I_ERR_INRCV (0x1 << 5)
+#define SUN4I_ERR_INTRANS (0x0 << 5)
+
+/* filter mode */
+#define SUN4I_FILTER_CLOSE 0
+#define SUN4I_SINGLE_FLTER_MODE 1
+#define SUN4I_DUAL_FILTER_MODE 2
+
+/* message buffer flags */
+#define SUN4I_MSG_EFF_FLAG BIT(7)
+#define SUN4I_MSG_RTR_FLAG BIT(6)
+
+/* max. number of interrupts handled in ISR */
+#define SUN4I_CAN_MAX_IRQ 20
+#define SUN4I_MODE_MAX_RETRIES 100
+
+struct sun4ican_priv {
+ struct can_priv can;
+ void __iomem *base;
+ struct clk *clk;
+ spinlock_t cmdreg_lock; /* lock for concurrent cmd register writes */
+};
+
+static const struct can_bittiming_const sun4ican_bittiming_const = {
+ .name = DRV_NAME,
+ .tseg1_min = 1,
+ .tseg1_max = 16,
+ .tseg2_min = 1,
+ .tseg2_max = 8,
+ .sjw_max = 4,
+ .brp_min = 1,
+ .brp_max = 64,
+ .brp_inc = 1,
+};
+
+static void sun4i_can_write_cmdreg(struct sun4ican_priv *priv, u8 val)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->cmdreg_lock, flags);
+ writel(val, priv->base + SUN4I_REG_CMD_ADDR);
+ spin_unlock_irqrestore(&priv->cmdreg_lock, flags);
+}
+
+static int set_normal_mode(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ int retry = SUN4I_MODE_MAX_RETRIES;
+ u32 mod_reg_val = 0;
+
+ do {
+ mod_reg_val = readl(priv->base + SUN4I_REG_MSEL_ADDR);
+ mod_reg_val &= ~SUN4I_MSEL_RESET_MODE;
+ writel(mod_reg_val, priv->base + SUN4I_REG_MSEL_ADDR);
+ } while (retry-- && (mod_reg_val & SUN4I_MSEL_RESET_MODE));
+
+ if (readl(priv->base + SUN4I_REG_MSEL_ADDR) & SUN4I_MSEL_RESET_MODE) {
+ netdev_err(dev,
+ "setting controller into normal mode failed!\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int set_reset_mode(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ int retry = SUN4I_MODE_MAX_RETRIES;
+ u32 mod_reg_val = 0;
+
+ do {
+ mod_reg_val = readl(priv->base + SUN4I_REG_MSEL_ADDR);
+ mod_reg_val |= SUN4I_MSEL_RESET_MODE;
+ writel(mod_reg_val, priv->base + SUN4I_REG_MSEL_ADDR);
+ } while (retry-- && !(mod_reg_val & SUN4I_MSEL_RESET_MODE));
+
+ if (!(readl(priv->base + SUN4I_REG_MSEL_ADDR) &
+ SUN4I_MSEL_RESET_MODE)) {
+ netdev_err(dev, "setting controller into reset mode failed!\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+/* bittiming is called in reset_mode only */
+static int sun4ican_set_bittiming(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ struct can_bittiming *bt = &priv->can.bittiming;
+ u32 cfg;
+
+ cfg = ((bt->brp - 1) & 0x3FF) |
+ (((bt->sjw - 1) & 0x3) << 14) |
+ (((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) << 16) |
+ (((bt->phase_seg2 - 1) & 0x7) << 20);
+ if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+ cfg |= 0x800000;
+
+ netdev_dbg(dev, "setting BITTIMING=0x%08x\n", cfg);
+ writel(cfg, priv->base + SUN4I_REG_BTIME_ADDR);
+
+ return 0;
+}
+
+static int sun4ican_get_berr_counter(const struct net_device *dev,
+ struct can_berr_counter *bec)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ u32 errors;
+ int err;
+
+ err = clk_prepare_enable(priv->clk);
+ if (err) {
+ netdev_err(dev, "could not enable clock\n");
+ return err;
+ }
+
+ errors = readl(priv->base + SUN4I_REG_ERRC_ADDR);
+
+ bec->txerr = errors & 0xFF;
+ bec->rxerr = (errors >> 16) & 0xFF;
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int sun4i_can_start(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ int err;
+ u32 mod_reg_val;
+
+ /* we need to enter the reset mode */
+ err = set_reset_mode(dev);
+ if (err) {
+ netdev_err(dev, "could not enter reset mode\n");
+ return err;
+ }
+
+ /* set filters - we accept all */
+ writel(0x00000000, priv->base + SUN4I_REG_ACPC_ADDR);
+ writel(0xFFFFFFFF, priv->base + SUN4I_REG_ACPM_ADDR);
+
+ /* clear error counters and error code capture */
+ writel(0, priv->base + SUN4I_REG_ERRC_ADDR);
+
+ /* enable interrupts */
+ if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+ writel(0xFF, priv->base + SUN4I_REG_INTEN_ADDR);
+ else
+ writel(0xFF & ~SUN4I_INTEN_BERR,
+ priv->base + SUN4I_REG_INTEN_ADDR);
+
+ /* enter the selected mode */
+ mod_reg_val = readl(priv->base + SUN4I_REG_MSEL_ADDR);
+ if (priv->can.ctrlmode & CAN_CTRLMODE_PRESUME_ACK)
+ mod_reg_val |= SUN4I_MSEL_LOOPBACK_MODE;
+ else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+ mod_reg_val |= SUN4I_MSEL_LISTEN_ONLY_MODE;
+ writel(mod_reg_val, priv->base + SUN4I_REG_MSEL_ADDR);
+
+ err = sun4ican_set_bittiming(dev);
+ if (err)
+ return err;
+
+ /* we are ready to enter the normal mode */
+ err = set_normal_mode(dev);
+ if (err) {
+ netdev_err(dev, "could not enter normal mode\n");
+ return err;
+ }
+
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+ return 0;
+}
+
+static int sun4i_can_stop(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ int err;
+
+ priv->can.state = CAN_STATE_STOPPED;
+ /* we need to enter reset mode */
+ err = set_reset_mode(dev);
+ if (err) {
+ netdev_err(dev, "could not enter reset mode\n");
+ return err;
+ }
+
+ /* disable all interrupts */
+ writel(0, priv->base + SUN4I_REG_INTEN_ADDR);
+
+ return 0;
+}
+
+static int sun4ican_set_mode(struct net_device *dev, enum can_mode mode)
+{
+ int err;
+
+ switch (mode) {
+ case CAN_MODE_START:
+ err = sun4i_can_start(dev);
+ if (err) {
+ netdev_err(dev, "starting CAN controller failed!\n");
+ return err;
+ }
+ if (netif_queue_stopped(dev))
+ netif_wake_queue(dev);
+ break;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+ return 0;
+}
+
+/* transmit a CAN message
+ * message layout in the sk_buff should be like this:
+ * xx xx xx xx ff ll 00 11 22 33 44 55 66 77
+ * [ can_id ] [flags] [len] [can data (up to 8 bytes]
+ */
+static int sun4ican_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ struct can_frame *cf = (struct can_frame *)skb->data;
+ u8 dlc;
+ u32 dreg, msg_flag_n;
+ canid_t id;
+ int i;
+
+ if (can_dropped_invalid_skb(dev, skb))
+ return NETDEV_TX_OK;
+
+ netif_stop_queue(dev);
+
+ id = cf->can_id;
+ dlc = cf->can_dlc;
+ msg_flag_n = dlc;
+
+ if (id & CAN_RTR_FLAG)
+ msg_flag_n |= SUN4I_MSG_RTR_FLAG;
+
+ if (id & CAN_EFF_FLAG) {
+ msg_flag_n |= SUN4I_MSG_EFF_FLAG;
+ dreg = SUN4I_REG_BUF5_ADDR;
+ writel((id >> 21) & 0xFF, priv->base + SUN4I_REG_BUF1_ADDR);
+ writel((id >> 13) & 0xFF, priv->base + SUN4I_REG_BUF2_ADDR);
+ writel((id >> 5) & 0xFF, priv->base + SUN4I_REG_BUF3_ADDR);
+ writel((id << 3) & 0xF8, priv->base + SUN4I_REG_BUF4_ADDR);
+ } else {
+ dreg = SUN4I_REG_BUF3_ADDR;
+ writel((id >> 3) & 0xFF, priv->base + SUN4I_REG_BUF1_ADDR);
+ writel((id << 5) & 0xE0, priv->base + SUN4I_REG_BUF2_ADDR);
+ }
+
+ for (i = 0; i < dlc; i++)
+ writel(cf->data[i], priv->base + (dreg + i * 4));
+
+ writel(msg_flag_n, priv->base + SUN4I_REG_BUF0_ADDR);
+
+ can_put_echo_skb(skb, dev, 0);
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+ sun4i_can_write_cmdreg(priv, SUN4I_CMD_SELF_RCV_REQ);
+ else
+ sun4i_can_write_cmdreg(priv, SUN4I_CMD_TRANS_REQ);
+
+ return NETDEV_TX_OK;
+}
+
+static void sun4i_can_rx(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ struct net_device_stats *stats = &dev->stats;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+ u8 fi;
+ u32 dreg;
+ canid_t id;
+ int i;
+
+ /* create zero'ed CAN frame buffer */
+ skb = alloc_can_skb(dev, &cf);
+ if (!skb)
+ return;
+
+ fi = readl(priv->base + SUN4I_REG_BUF0_ADDR);
+ cf->can_dlc = get_can_dlc(fi & 0x0F);
+ if (fi & SUN4I_MSG_EFF_FLAG) {
+ dreg = SUN4I_REG_BUF5_ADDR;
+ id = (readl(priv->base + SUN4I_REG_BUF1_ADDR) << 21) |
+ (readl(priv->base + SUN4I_REG_BUF2_ADDR) << 13) |
+ (readl(priv->base + SUN4I_REG_BUF3_ADDR) << 5) |
+ ((readl(priv->base + SUN4I_REG_BUF4_ADDR) >> 3) & 0x1f);
+ id |= CAN_EFF_FLAG;
+ } else {
+ dreg = SUN4I_REG_BUF3_ADDR;
+ id = (readl(priv->base + SUN4I_REG_BUF1_ADDR) << 3) |
+ ((readl(priv->base + SUN4I_REG_BUF2_ADDR) >> 5) & 0x7);
+ }
+
+ /* remote frame ? */
+ if (fi & SUN4I_MSG_RTR_FLAG)
+ id |= CAN_RTR_FLAG;
+ else
+ for (i = 0; i < cf->can_dlc; i++)
+ cf->data[i] = readl(priv->base + dreg + i * 4);
+
+ cf->can_id = id;
+
+ sun4i_can_write_cmdreg(priv, SUN4I_CMD_RELEASE_RBUF);
+
+ stats->rx_packets++;
+ stats->rx_bytes += cf->can_dlc;
+ netif_rx(skb);
+
+ can_led_event(dev, CAN_LED_EVENT_RX);
+}
+
+static int sun4i_can_err(struct net_device *dev, u8 isrc, u8 status)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ struct net_device_stats *stats = &dev->stats;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+ enum can_state state = priv->can.state;
+ enum can_state rx_state, tx_state;
+ unsigned int rxerr, txerr, errc;
+ u32 ecc, alc;
+
+ /* we don't skip if alloc fails because we want the stats anyhow */
+ skb = alloc_can_err_skb(dev, &cf);
+
+ errc = readl(priv->base + SUN4I_REG_ERRC_ADDR);
+ rxerr = (errc >> 16) & 0xFF;
+ txerr = errc & 0xFF;
+
+ if (skb) {
+ cf->data[6] = txerr;
+ cf->data[7] = rxerr;
+ }
+
+ if (isrc & SUN4I_INT_DATA_OR) {
+ /* data overrun interrupt */
+ netdev_dbg(dev, "data overrun interrupt\n");
+ if (likely(skb)) {
+ cf->can_id |= CAN_ERR_CRTL;
+ cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+ }
+ stats->rx_over_errors++;
+ stats->rx_errors++;
+ /* clear bit */
+ sun4i_can_write_cmdreg(priv, SUN4I_CMD_CLEAR_OR_FLAG);
+ }
+ if (isrc & SUN4I_INT_ERR_WRN) {
+ /* error warning interrupt */
+ netdev_dbg(dev, "error warning interrupt\n");
+
+ if (status & SUN4I_STA_BUS_OFF)
+ state = CAN_STATE_BUS_OFF;
+ else if (status & SUN4I_STA_ERR_STA)
+ state = CAN_STATE_ERROR_WARNING;
+ else
+ state = CAN_STATE_ERROR_ACTIVE;
+ }
+ if (isrc & SUN4I_INT_BUS_ERR) {
+ /* bus error interrupt */
+ netdev_dbg(dev, "bus error interrupt\n");
+ priv->can.can_stats.bus_error++;
+ stats->rx_errors++;
+
+ if (likely(skb)) {
+ ecc = readl(priv->base + SUN4I_REG_STA_ADDR);
+
+ cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+ switch (ecc & SUN4I_STA_MASK_ERR) {
+ case SUN4I_STA_BIT_ERR:
+ cf->data[2] |= CAN_ERR_PROT_BIT;
+ break;
+ case SUN4I_STA_FORM_ERR:
+ cf->data[2] |= CAN_ERR_PROT_FORM;
+ break;
+ case SUN4I_STA_STUFF_ERR:
+ cf->data[2] |= CAN_ERR_PROT_STUFF;
+ break;
+ default:
+ cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+ cf->data[3] = (ecc & SUN4I_STA_ERR_SEG_CODE)
+ >> 16;
+ break;
+ }
+ /* error occurred during transmission? */
+ if ((ecc & SUN4I_STA_ERR_DIR) == 0)
+ cf->data[2] |= CAN_ERR_PROT_TX;
+ }
+ }
+ if (isrc & SUN4I_INT_ERR_PASSIVE) {
+ /* error passive interrupt */
+ netdev_dbg(dev, "error passive interrupt\n");
+ if (state == CAN_STATE_ERROR_PASSIVE)
+ state = CAN_STATE_ERROR_WARNING;
+ else
+ state = CAN_STATE_ERROR_PASSIVE;
+ }
+ if (isrc & SUN4I_INT_ARB_LOST) {
+ /* arbitration lost interrupt */
+ netdev_dbg(dev, "arbitration lost interrupt\n");
+ alc = readl(priv->base + SUN4I_REG_STA_ADDR);
+ priv->can.can_stats.arbitration_lost++;
+ stats->tx_errors++;
+ if (likely(skb)) {
+ cf->can_id |= CAN_ERR_LOSTARB;
+ cf->data[0] = (alc & 0x1f) >> 8;
+ }
+ }
+
+ if (state != priv->can.state) {
+ tx_state = txerr >= rxerr ? state : 0;
+ rx_state = txerr <= rxerr ? state : 0;
+
+ if (likely(skb))
+ can_change_state(dev, cf, tx_state, rx_state);
+ else
+ priv->can.state = state;
+ if (state == CAN_STATE_BUS_OFF)
+ can_bus_off(dev);
+ }
+
+ if (likely(skb)) {
+ stats->rx_packets++;
+ stats->rx_bytes += cf->can_dlc;
+ netif_rx(skb);
+ } else {
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static irqreturn_t sun4i_can_interrupt(int irq, void *dev_id)
+{
+ struct net_device *dev = (struct net_device *)dev_id;
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ struct net_device_stats *stats = &dev->stats;
+ u8 isrc, status;
+ int n = 0;
+
+ while ((isrc = readl(priv->base + SUN4I_REG_INT_ADDR)) &&
+ (n < SUN4I_CAN_MAX_IRQ)) {
+ n++;
+ status = readl(priv->base + SUN4I_REG_STA_ADDR);
+
+ if (isrc & SUN4I_INT_WAKEUP)
+ netdev_warn(dev, "wakeup interrupt\n");
+
+ if (isrc & SUN4I_INT_TBUF_VLD) {
+ /* transmission complete interrupt */
+ stats->tx_bytes +=
+ readl(priv->base +
+ SUN4I_REG_RBUF_RBACK_START_ADDR) & 0xf;
+ stats->tx_packets++;
+ can_get_echo_skb(dev, 0);
+ netif_wake_queue(dev);
+ can_led_event(dev, CAN_LED_EVENT_TX);
+ }
+ if (isrc & SUN4I_INT_RBUF_VLD) {
+ /* receive interrupt */
+ while (status & SUN4I_STA_RBUF_RDY) {
+ /* RX buffer is not empty */
+ sun4i_can_rx(dev);
+ status = readl(priv->base + SUN4I_REG_STA_ADDR);
+ }
+ }
+ if (isrc &
+ (SUN4I_INT_DATA_OR | SUN4I_INT_ERR_WRN | SUN4I_INT_BUS_ERR |
+ SUN4I_INT_ERR_PASSIVE | SUN4I_INT_ARB_LOST)) {
+ /* error interrupt */
+ if (sun4i_can_err(dev, isrc, status))
+ netdev_err(dev, "can't allocate buffer - clearing pending interrupts\n");
+ }
+ /* clear interrupts */
+ writel(isrc, priv->base + SUN4I_REG_INT_ADDR);
+ readl(priv->base + SUN4I_REG_INT_ADDR);
+ }
+ if (n >= SUN4I_CAN_MAX_IRQ)
+ netdev_dbg(dev, "%d messages handled in ISR", n);
+
+ return (n) ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int sun4ican_open(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+ int err;
+
+ /* common open */
+ err = open_candev(dev);
+ if (err)
+ return err;
+
+ /* register interrupt handler */
+ err = request_irq(dev->irq, sun4i_can_interrupt, 0, dev->name, dev);
+ if (err) {
+ netdev_err(dev, "request_irq err: %d\n", err);
+ goto exit_irq;
+ }
+
+ /* turn on clocking for CAN peripheral block */
+ err = clk_prepare_enable(priv->clk);
+ if (err) {
+ netdev_err(dev, "could not enable CAN peripheral clock\n");
+ goto exit_clock;
+ }
+
+ err = sun4i_can_start(dev);
+ if (err) {
+ netdev_err(dev, "could not start CAN peripheral\n");
+ goto exit_can_start;
+ }
+
+ can_led_event(dev, CAN_LED_EVENT_OPEN);
+ netif_start_queue(dev);
+
+ return 0;
+
+exit_can_start:
+ clk_disable_unprepare(priv->clk);
+exit_clock:
+ free_irq(dev->irq, dev);
+exit_irq:
+ close_candev(dev);
+ return err;
+}
+
+static int sun4ican_close(struct net_device *dev)
+{
+ struct sun4ican_priv *priv = netdev_priv(dev);
+
+ netif_stop_queue(dev);
+ sun4i_can_stop(dev);
+ clk_disable_unprepare(priv->clk);
+
+ free_irq(dev->irq, dev);
+ close_candev(dev);
+ can_led_event(dev, CAN_LED_EVENT_STOP);
+
+ return 0;
+}
+
+static const struct net_device_ops sun4ican_netdev_ops = {
+ .ndo_open = sun4ican_open,
+ .ndo_stop = sun4ican_close,
+ .ndo_start_xmit = sun4ican_start_xmit,
+};
+
+static const struct of_device_id sun4ican_of_match[] = {
+ {.compatible = "allwinner,sun4i-a10-can"},
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, sun4ican_of_match);
+
+static int sun4ican_remove(struct platform_device *pdev)
+{
+ struct net_device *dev = platform_get_drvdata(pdev);
+
+ unregister_netdev(dev);
+ free_candev(dev);
+
+ return 0;
+}
+
+static int sun4ican_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct resource *mem;
+ struct clk *clk;
+ void __iomem *addr;
+ int err, irq;
+ struct net_device *dev;
+ struct sun4ican_priv *priv;
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "unable to request clock\n");
+ err = -ENODEV;
+ goto exit;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "could not get a valid irq\n");
+ err = -ENODEV;
+ goto exit;
+ }
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ addr = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(addr)) {
+ err = -EBUSY;
+ goto exit;
+ }
+
+ dev = alloc_candev(sizeof(struct sun4ican_priv), 1);
+ if (!dev) {
+ dev_err(&pdev->dev,
+ "could not allocate memory for CAN device\n");
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ dev->netdev_ops = &sun4ican_netdev_ops;
+ dev->irq = irq;
+ dev->flags |= IFF_ECHO;
+
+ priv = netdev_priv(dev);
+ priv->can.clock.freq = clk_get_rate(clk);
+ priv->can.bittiming_const = &sun4ican_bittiming_const;
+ priv->can.do_set_mode = sun4ican_set_mode;
+ priv->can.do_get_berr_counter = sun4ican_get_berr_counter;
+ priv->can.ctrlmode_supported = CAN_CTRLMODE_BERR_REPORTING |
+ CAN_CTRLMODE_LISTENONLY |
+ CAN_CTRLMODE_LOOPBACK |
+ CAN_CTRLMODE_PRESUME_ACK |
+ CAN_CTRLMODE_3_SAMPLES;
+ priv->base = addr;
+ priv->clk = clk;
+ spin_lock_init(&priv->cmdreg_lock);
+
+ platform_set_drvdata(pdev, dev);
+ SET_NETDEV_DEV(dev, &pdev->dev);
+
+ err = register_candev(dev);
+ if (err) {
+ dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
+ DRV_NAME, err);
+ goto exit_free;
+ }
+ devm_can_led_init(dev);
+
+ dev_info(&pdev->dev, "device registered (base=%p, irq=%d)\n",
+ priv->base, dev->irq);
+
+ return 0;
+
+exit_free:
+ free_candev(dev);
+exit:
+ return err;
+}
+
+static struct platform_driver sun4i_can_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .of_match_table = sun4ican_of_match,
+ },
+ .probe = sun4ican_probe,
+ .remove = sun4ican_remove,
+};
+
+module_platform_driver(sun4i_can_driver);
+
+MODULE_AUTHOR("Peter Chen <xingkongcp@gmail.com>");
+MODULE_AUTHOR("Gerhard Bertelsmann <info@gerhard-bertelsmann.de>");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION(DRV_NAME "CAN driver for Allwinner SoCs (A10/A20)");