ENGR00319455-1 can: m_can: add Bosch M_CAN controller support

The patch adds the basic CAN TX/RX function support for Bosch M_CAN controller.
For TX, only one dedicated tx buffer is used for sending data.
For RX, RXFIFO 0 is used for receiving data to avoid overflow.
Rx FIFO 1 and Rx Buffers are not used currently, as well as Tx Event FIFO.

Due to the message ram can be shared by multi m_can instances
and the fifo element is configurable which is SoC dependant,
the design is to parse the message ram related configuration data from device
tree rather than hardcode define it in driver which can make the message
ram using fully transparently to M_CAN controller driver,
then we can gain better driver maintainability and future features upgrade.

M_CAN also supports CANFD protocol features like data payload up to 64 bytes
and bitrate switch at runtime, however, this patch still does not add the
support for these features.

Signed-off-by: Dong Aisheng <b29396@freescale.com>

4 files changed, 904 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/can/m_can.txt b/Documentation/devicetree/bindings/net/can/m_can.txt
new file mode 100644
index 000000000000..2b22d027e6b6
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/can/m_can.txt
@@ -0,0 +1,29 @@
+Bosch MCAN controller Device Tree Bindings
+-------------------------------------------------
+
+Required properties:
+- compatible            : Should be "bosch,m_can" for M_CAN controllers
+- reg                   : physical base address and size of the M_CAN
+                          registers map and message ram
+- interrupts            : property with a value describing the interrupt
+                          number
+- clocks                : clocks used by controller
+- mram-cfg              : message ram configuration data, the format is
+  <offset sidf_elems xidf_elems rxf1_elems rxb_elems txe_elems txb_elems>
+  The 'offset' is the address offset inside the message ram. This is usually set
+  if you're using the shared message ram while the other part is used by another
+  m_can controller.
+  The left cell are all the number of each elements inside the message ram.
+  Please refer to 2.4.1 Message RAM Con.guration in Bosch M_CAN user mannual
+  for each elements definition.
+
+Example:
+canfd1: canfd@020e8000 {
+        compatible = "bosch,m_can";
+        reg = <0x020e8000 0x4000>, <0x02298000 0x4000>;
+        reg-names = "canfd", "message_ram";
+        interrupts = <0 114 0x04>;
+        clocks = <&clks IMX6SX_CLK_CANFD>;
+        mram-cfg = <0x0 0 0 32 32 32 0 1>;
+        status = "disabled";
+};
diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index e456b70933c2..15483e2c6e47 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -128,6 +128,11 @@ config CAN_GRCAN
           endian syntheses of the cores would need some modifications on
           the hardware level to work.
 
+config CAN_M_CAN
+        tristate "Bosch M_CAN devices"
+        ---help---
+          Say Y here if you want to support for Bosch M_CAN controller.
+
 source "drivers/net/can/mscan/Kconfig"
 
 source "drivers/net/can/sja1000/Kconfig"
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c7440392adbb..f5d2fffc4302 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -16,6 +16,7 @@ obj-y				+= softing/
 obj-$(CONFIG_CAN_SJA1000)       += sja1000/
 obj-$(CONFIG_CAN_MSCAN)         += mscan/
 obj-$(CONFIG_CAN_C_CAN)         += c_can/
+obj-$(CONFIG_CAN_M_CAN)         += m_can.o
 obj-$(CONFIG_CAN_CC770)         += cc770/
 obj-$(CONFIG_CAN_AT91)          += at91_can.o
 obj-$(CONFIG_CAN_TI_HECC)       += ti_hecc.o
diff --git a/drivers/net/can/m_can.c b/drivers/net/can/m_can.c
new file mode 100644
index 000000000000..4397cfe2ec31
--- /dev/null
+++ b/drivers/net/can/m_can.c
@@ -0,0 +1,869 @@
+/*
+ * CAN bus driver for Bosch M_CAN controller
+ *
+ * Copyright (C) 2014 Freescale Semiconductor, Inc.
+ *      Dong Aisheng <b29396@freescale.com>
+ *
+ * Bosch M_CAN user manual can be obtained from:
+ * http://www.bosch-semiconductors.de/media/pdf_1/ipmodules_1/m_can/
+ * mcan_users_manual_v302.pdf
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+
+#include <linux/can/dev.h>
+
+/* napi related */
+#define M_CAN_NAPI_WEIGHT       64
+
+/* registers definition */
+enum m_can_reg {
+        M_CAN_CREL      = 0x0,
+        M_CAN_ENDN      = 0x4,
+        M_CAN_CUST      = 0x8,
+        M_CAN_FBTP      = 0xc,
+        M_CAN_TEST      = 0x10,
+        M_CAN_RWD       = 0x14,
+        M_CAN_CCCR      = 0x18,
+        M_CAN_BTP       = 0x1c,
+        M_CAN_TSCC      = 0x20,
+        M_CAN_TSCV      = 0x24,
+        M_CAN_TOCC      = 0x28,
+        M_CAN_TOCV      = 0x2c,
+        M_CAN_ECR       = 0x40,
+        M_CAN_PSR       = 0x44,
+        M_CAN_IR        = 0x50,
+        M_CAN_IE        = 0x54,
+        M_CAN_ILS       = 0x58,
+        M_CAN_ILE       = 0x5c,
+        M_CAN_GFC       = 0x80,
+        M_CAN_SIDFC     = 0x84,
+        M_CAN_XIDFC     = 0x88,
+        M_CAN_XIDAM     = 0x90,
+        M_CAN_HPMS      = 0x94,
+        M_CAN_NDAT1     = 0x98,
+        M_CAN_NDAT2     = 0x9c,
+        M_CAN_RXF0C     = 0xa0,
+        M_CAN_RXF0S     = 0xa4,
+        M_CAN_RXF0A     = 0xa8,
+        M_CAN_RXBC      = 0xac,
+        M_CAN_RXF1C     = 0xb0,
+        M_CAN_RXF1S     = 0xb4,
+        M_CAN_RXF1A     = 0xb8,
+        M_CAN_RXESC     = 0xbc,
+        M_CAN_TXBC      = 0xc0,
+        M_CAN_TXFQS     = 0xc4,
+        M_CAN_TXESC     = 0xc8,
+        M_CAN_TXBRP     = 0xcc,
+        M_CAN_TXBAR     = 0xd0,
+        M_CAN_TXBCR     = 0xd4,
+        M_CAN_TXBTO     = 0xd8,
+        M_CAN_TXBCF     = 0xdc,
+        M_CAN_TXBTIE    = 0xe0,
+        M_CAN_TXBCIE    = 0xe4,
+        M_CAN_TXEFC     = 0xf0,
+        M_CAN_TXEFS     = 0xf4,
+        M_CAN_TXEFA     = 0xf8,
+};
+
+/* CC Control Register(CCCR) */
+#define CCCR_CCE        BIT(1)
+#define CCCR_INIT       BIT(0)
+
+/* Bit Timing & Prescaler Register (BTP) */
+#define BTR_BRP_MASK            0x3ff
+#define BTR_BRP_SHIFT           16
+#define BTR_TSEG1_SHIFT         8
+#define BTR_TSEG1_MASK          (0x3f << BTR_TSEG1_SHIFT)
+#define BTR_TSEG2_SHIFT         4
+#define BTR_TSEG2_MASK          (0xf << BTR_TSEG2_SHIFT)
+#define BTR_SJW_SHIFT           0
+#define BTR_SJW_MASK            0xf
+
+/* Interrupt Register(IR) */
+#define IR_ALL_INT      0xffffffff
+#define IR_STE          BIT(31)
+#define IR_FOE          BIT(30)
+#define IR_ACKE         BIT(29)
+#define IR_BE           BIT(28)
+#define IR_CRCE         BIT(27)
+#define IR_WDI          BIT(26)
+#define IR_BO           BIT(25)
+#define IR_EW           BIT(24)
+#define IR_EP           BIT(23)
+#define IR_ELO          BIT(22)
+#define IR_BEU          BIT(21)
+#define IR_BEC          BIT(20)
+#define IR_DRX          BIT(19)
+#define IR_TOO          BIT(18)
+#define IR_MRAF         BIT(17)
+#define IR_TSW          BIT(16)
+#define IR_TEFL         BIT(15)
+#define IR_TEFF         BIT(14)
+#define IR_TEFW         BIT(13)
+#define IR_TEFN         BIT(12)
+#define IR_TFE          BIT(11)
+#define IR_TCF          BIT(10)
+#define IR_TC           BIT(9)
+#define IR_HPM          BIT(8)
+#define IR_RF1L         BIT(7)
+#define IR_RF1F         BIT(6)
+#define IR_RF1W         BIT(5)
+#define IR_RF1N         BIT(4)
+#define IR_RF0L         BIT(3)
+#define IR_RF0F         BIT(2)
+#define IR_RF0W         BIT(1)
+#define IR_RF0N         BIT(0)
+#define IR_ERR_ALL      (IR_STE | IR_FOE | IR_ACKE | IR_BE | IR_CRCE | \
+                IR_WDI | IR_BO | IR_EW | IR_EP | IR_ELO | IR_BEU | \
+                IR_BEC | IR_TOO | IR_MRAF | IR_TSW | IR_TEFL | IR_RF1L | \
+                IR_RF0L)
+
+/* Rx FIFO 0/1 Configuration (RXF0C/RXF1C) */
+#define RXFC_FWM_OFF    24
+#define RXFC_FWM_MASK   0x7f
+#define RXFC_FWM_1      (1 << RXFC_FWM_OFF)
+#define RXFC_FS_OFF     16
+#define RXFC_FS_MASK    0x7f
+
+/* Rx FIFO 0/1 Status (RXF0S/RXF1S) */
+#define RXFS_RFL        BIT(25)
+#define RXFS_FF         BIT(24)
+#define RXFS_FPI_OFF    16
+#define RXFS_FPI_MASK   0x3f0000
+#define RXFS_FGI_OFF    8
+#define RXFS_FGI_MASK   0x3f00
+#define RXFS_FFL_MASK   0x7f
+
+/* Tx Buffer Configuration(TXBC) */
+#define TXBC_NDTB_OFF   16
+#define TXBC_NDTB_MASK  0x3f
+
+/* Tx Buffer Element Size Configuration(TXESC) */
+#define TXESC_TBDS_8BYTES       0x0
+/* Tx Buffer Element */
+#define TX_BUF_XTD      BIT(30)
+#define TX_BUF_RTR      BIT(29)
+
+/* Rx Buffer Element Size Configuration(TXESC) */
+#define M_CAN_RXESC_8BYTES      0x0
+/* Tx Buffer Element */
+#define RX_BUF_ESI      BIT(31)
+#define RX_BUF_XTD      BIT(30)
+#define RX_BUF_RTR      BIT(29)
+
+/* Message RAM Configuration (in bytes) */
+#define SIDF_ELEMENT_SIZE       4
+#define XIDF_ELEMENT_SIZE       8
+#define RXF0_ELEMENT_SIZE       16
+#define RXF1_ELEMENT_SIZE       16
+#define RXB_ELEMENT_SIZE        16
+#define TXE_ELEMENT_SIZE        8
+#define TXB_ELEMENT_SIZE        16
+
+/* m_can private data structure */
+struct m_can_priv {
+        struct can_priv can;    /* must be the first member */
+        struct napi_struct napi;
+        struct net_device *dev;
+        struct device *device;
+        struct clk *clk;
+        void __iomem *base;
+        u32 irqstatus;
+
+        /* message ram configuration */
+        void __iomem *mram_base;
+        u32 mram_off;
+        u32 sidf_elems;
+        u32 sidf_off;
+        u32 xidf_elems;
+        u32 xidf_off;
+        u32 rxf0_elems;
+        u32 rxf0_off;
+        u32 rxf1_elems;
+        u32 rxf1_off;
+        u32 rxb_elems;
+        u32 rxb_off;
+        u32 txe_elems;
+        u32 txe_off;
+        u32 txb_elems;
+        u32 txb_off;
+};
+
+static inline u32 m_can_read(const struct m_can_priv *priv, enum m_can_reg reg)
+{
+        return readl(priv->base + reg);
+}
+
+static inline void m_can_write(const struct m_can_priv *priv,
+                                enum m_can_reg reg, u32 val)
+{
+        writel(val, priv->base + reg);
+}
+
+static inline void m_can_config_endisable(const struct m_can_priv *priv,
+                                bool enable)
+{
+        u32 cccr = m_can_read(priv, M_CAN_CCCR);
+        u32 timeout = 10, val;
+
+        if (enable) {
+                /* enable m_can configuration */
+                m_can_write(priv, M_CAN_CCCR, cccr | CCCR_INIT);
+                /* CCCR.CCE can only be set/reset while CCCR.INIT = '1' */
+                m_can_write(priv, M_CAN_CCCR, cccr | CCCR_INIT | CCCR_CCE);
+        } else {
+                m_can_write(priv, M_CAN_CCCR, cccr & ~(CCCR_INIT | CCCR_CCE));
+        }
+
+        /* there's a delay for module initialization */
+        val = enable ? CCCR_INIT | CCCR_CCE : 0;
+        while ((m_can_read(priv, M_CAN_CCCR) & (CCCR_INIT | CCCR_CCE))
+                                != val) {
+                if (timeout == 0) {
+                        netdev_warn(priv->dev, "Failed to init module\n");
+                        return;
+                }
+                timeout--;
+                udelay(1);
+        }
+}
+
+static void m_can_enable_all_interrupts(struct m_can_priv *priv, bool enable)
+{
+        m_can_write(priv, M_CAN_ILE, enable ? 0x00000003 : 0x0);
+}
+
+static int m_can_do_rx_poll(struct net_device *dev, int quota)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+        struct net_device_stats *stats = &dev->stats;
+        struct sk_buff *skb;
+        struct can_frame *frame;
+        u32 rxfs, flags, fgi;
+        u32 num_rx_pkts = 0;
+
+        rxfs = m_can_read(priv, M_CAN_RXF0S);
+        if (!(rxfs & RXFS_FFL_MASK)) {
+                netdev_dbg(dev, "no messages in fifo0\n");
+                return 0;
+        }
+
+        while ((rxfs & RXFS_FFL_MASK) && (quota > 0)) {
+                netdev_dbg(dev, "fifo0 status 0x%x\n", rxfs);
+                if (rxfs & RXFS_RFL)
+                        netdev_warn(dev, "Rx FIFO 0 Message Lost\n");
+
+                skb = alloc_can_skb(dev, &frame);
+                if (!skb) {
+                        stats->rx_dropped++;
+                        return -ENOMEM;
+                }
+
+                fgi = (rxfs & RXFS_FGI_MASK) >> RXFS_FGI_OFF;
+                flags = readl(priv->mram_base + priv->rxf0_off + fgi * 16);
+                if (flags & RX_BUF_XTD)
+                        frame->can_id = (flags & CAN_EFF_MASK) | CAN_EFF_FLAG;
+                else
+                        frame->can_id = (flags >> 18) & CAN_SFF_MASK;
+                netdev_dbg(dev, "R0 0x%x\n", flags);
+
+                if (flags & RX_BUF_RTR) {
+                        frame->can_id |= CAN_RTR_FLAG;
+                } else {
+                        flags = readl(priv->mram_base +
+                                        priv->rxf0_off + fgi * 16 + 0x4);
+                        frame->can_dlc = get_can_dlc((flags >> 16) & 0x0F);
+                        netdev_dbg(dev, "R1 0x%x\n", flags);
+
+                        *(u32 *)(frame->data + 0) = readl(priv->mram_base +
+                                        priv->rxf0_off + fgi * 16 + 0x8);
+                        *(u32 *)(frame->data + 4) = readl(priv->mram_base +
+                                        priv->rxf0_off + fgi * 16 + 0xC);
+                        netdev_dbg(dev, "R2 0x%x\n", *(u32 *)(frame->data + 0));
+                        netdev_dbg(dev, "R3 0x%x\n", *(u32 *)(frame->data + 4));
+                }
+
+                /* acknowledge rx fifo 0 */
+                m_can_write(priv, M_CAN_RXF0A, fgi);
+
+                netif_receive_skb(skb);
+                netdev_dbg(dev, "new packet received\n");
+
+                stats->rx_packets++;
+                stats->rx_bytes += frame->can_dlc;
+
+                can_led_event(dev, CAN_LED_EVENT_RX);
+
+                quota--;
+                num_rx_pkts++;
+                rxfs = m_can_read(priv, M_CAN_RXF0S);
+        };
+
+        return num_rx_pkts;
+}
+
+static int m_can_poll(struct napi_struct *napi, int quota)
+{
+        struct net_device *dev = napi->dev;
+        struct m_can_priv *priv = netdev_priv(dev);
+        u32 work_done = 0;
+        u32 irqstatus;
+
+        irqstatus = m_can_read(priv, M_CAN_IR);
+        if (irqstatus)
+                netdev_dbg(dev, "irqstatus updated! new 0x%x old 0x%x rxf0s 0x%x\n",
+                        irqstatus, priv->irqstatus,
+                        m_can_read(priv, M_CAN_RXF0S));
+
+        irqstatus = irqstatus | priv->irqstatus;
+        if (!irqstatus)
+                goto end;
+
+        if (irqstatus & IR_RF0N)
+                /* handle events corresponding to receive message objects */
+                work_done += m_can_do_rx_poll(dev, (quota - work_done));
+
+        if (work_done < quota) {
+                napi_complete(napi);
+                /* enable all IRQs */
+                m_can_enable_all_interrupts(priv, true);
+        }
+
+end:
+        return work_done;
+}
+
+static irqreturn_t m_can_isr(int irq, void *dev_id)
+{
+        struct net_device *dev = (struct net_device *)dev_id;
+        struct m_can_priv *priv = netdev_priv(dev);
+        struct net_device_stats *stats = &dev->stats;
+        u32 ir;
+
+        ir = m_can_read(priv, M_CAN_IR);
+        if (!ir)
+                return IRQ_NONE;
+
+        netdev_dbg(dev, "ir 0x%x rxfs0 0x%x\n", ir,
+                        m_can_read(priv, M_CAN_RXF0S));
+
+        /* ACK all irqs */
+        if (ir & IR_ALL_INT)
+                m_can_write(priv, M_CAN_IR, ir);
+
+        if (ir & IR_ERR_ALL) {
+                netdev_dbg(dev, "bus error\n");
+                /* TODO: handle bus error */
+        }
+
+        /* save irqstatus for later using */
+        priv->irqstatus = ir;
+
+        /*
+         * schedule NAPI in case of
+         * - rx IRQ
+         * - state change IRQ(TODO)
+         * - bus error IRQ and bus error reporting (TODO)
+         */
+        if (ir & IR_RF0N) {
+                m_can_enable_all_interrupts(priv, false);
+                napi_schedule(&priv->napi);
+        }
+
+        /* FIFO overflow */
+        if (ir & IR_RF0L) {
+                dev->stats.rx_over_errors++;
+                dev->stats.rx_errors++;
+        }
+
+        /* transmission complete interrupt */
+        if (ir & IR_TC) {
+                netdev_dbg(dev, "tx complete\n");
+                stats->tx_bytes += can_get_echo_skb(dev, 0);
+                stats->tx_packets++;
+                can_led_event(dev, CAN_LED_EVENT_TX);
+                netif_wake_queue(dev);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static const struct can_bittiming_const m_can_bittiming_const = {
+        .name = KBUILD_MODNAME,
+        .tseg1_min = 2,         /* Time segment 1 = prop_seg + phase_seg1 */
+        .tseg1_max = 64,
+        .tseg2_min = 1,         /* Time segment 2 = phase_seg2 */
+        .tseg2_max = 16,
+        .sjw_max = 16,
+        .brp_min = 1,
+        .brp_max = 1024,
+        .brp_inc = 1,
+};
+
+static int m_can_set_bittiming(struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+        const struct can_bittiming *bt = &priv->can.bittiming;
+        u16 brp, sjw, tseg1, tseg2;
+        u32 reg_btp;
+
+        brp = bt->brp - 1;
+        sjw = bt->sjw - 1;
+        tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
+        tseg2 = bt->phase_seg2 - 1;
+        reg_btp = (brp << BTR_BRP_SHIFT) | (sjw << BTR_SJW_SHIFT) |
+                        (tseg1 << BTR_TSEG1_SHIFT) | (tseg2 << BTR_TSEG2_SHIFT);
+        m_can_write(priv, M_CAN_BTP, reg_btp);
+        netdev_dbg(dev, "setting BTP 0x%x\n", reg_btp);
+
+        return 0;
+}
+
+/*
+ * Configure M_CAN chip:
+ * - set rx buffer/fifo element size
+ * - configure rx fifo
+ * - accept non-matching frame into fifo 0
+ * - configure tx buffer
+ * - setup bittiming
+ * - TODO:
+ *   1) other working modes support like monitor, loopback...
+ *   2) lec error status report enable
+ */
+static void m_can_chip_config(struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+
+        m_can_config_endisable(priv, true);
+
+        /* RX Buffer/FIFO Element Size 8 bytes data field */
+        m_can_write(priv, M_CAN_RXESC, M_CAN_RXESC_8BYTES);
+
+        /* Accept Non-matching Frames Into FIFO 0 */
+        m_can_write(priv, M_CAN_GFC, 0x0);
+
+        /* only support one Tx Buffer currently */
+        m_can_write(priv, M_CAN_TXBC, (1 << TXBC_NDTB_OFF) |
+                (priv->mram_off + priv->txb_off));
+
+        /* only support 8 bytes firstly */
+        m_can_write(priv, M_CAN_TXESC, TXESC_TBDS_8BYTES);
+
+        m_can_write(priv, M_CAN_TXEFC, 0x00010000 |
+                (priv->mram_off + priv->txe_off));
+
+        /* rx fifo configuration, blocking mode, fifo size 1 */
+        m_can_write(priv, M_CAN_RXF0C, (priv->rxf0_elems << RXFC_FS_OFF) |
+                RXFC_FWM_1 | (priv->mram_off + priv->rxf0_off));
+
+        m_can_write(priv, M_CAN_RXF1C, (priv->rxf1_elems << RXFC_FS_OFF) |
+                RXFC_FWM_1 | (priv->mram_off + priv->rxf1_off));
+
+        /* enable all interrupts */
+        m_can_write(priv, M_CAN_IR, IR_ALL_INT);
+        m_can_write(priv, M_CAN_IE, IR_ALL_INT);
+        m_can_write(priv, M_CAN_ILS, 0xFFFF0000);
+
+        /* set bittiming params */
+        m_can_set_bittiming(dev);
+
+        m_can_config_endisable(priv, false);
+}
+
+static void m_can_start(struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+
+        /* basic m_can configuration */
+        m_can_chip_config(dev);
+
+        priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+        /* enable status change, error and module interrupts */
+        m_can_enable_all_interrupts(priv, true);
+}
+
+static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
+{
+        switch (mode) {
+        case CAN_MODE_START:
+                m_can_start(dev);
+                netif_wake_queue(dev);
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        return 0;
+}
+
+static int m_can_get_berr_counter(const struct net_device *dev,
+                                  struct can_berr_counter *bec)
+{
+        /* TODO */
+
+        return 0;
+}
+
+static void free_m_can_dev(struct net_device *dev)
+{
+        free_candev(dev);
+}
+
+static struct net_device *alloc_m_can_dev(void)
+{
+        struct net_device *dev;
+        struct m_can_priv *priv;
+
+        dev = alloc_candev(sizeof(struct m_can_priv), 1);
+        if (!dev)
+                return NULL;
+
+        priv = netdev_priv(dev);
+        netif_napi_add(dev, &priv->napi, m_can_poll, M_CAN_NAPI_WEIGHT);
+
+        priv->dev = dev;
+        priv->can.bittiming_const = &m_can_bittiming_const;
+        priv->can.do_set_mode = m_can_set_mode;
+        priv->can.do_get_berr_counter = m_can_get_berr_counter;
+        priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
+                                        CAN_CTRLMODE_LISTENONLY |
+                                        CAN_CTRLMODE_BERR_REPORTING;
+
+        return dev;
+}
+
+
+static int m_can_open(struct net_device *dev)
+{
+        int err;
+        struct m_can_priv *priv = netdev_priv(dev);
+
+        clk_prepare_enable(priv->clk);
+
+        /* open the can device */
+        err = open_candev(dev);
+        if (err) {
+                netdev_err(dev, "failed to open can device\n");
+                goto exit_open_fail;
+        }
+
+        /* register interrupt handler */
+        err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
+                                dev);
+        if (err < 0) {
+                netdev_err(dev, "failed to request interrupt\n");
+                goto exit_irq_fail;
+        }
+
+        /* start the m_can controller */
+        m_can_start(dev);
+
+        can_led_event(dev, CAN_LED_EVENT_OPEN);
+        napi_enable(&priv->napi);
+        netif_start_queue(dev);
+
+        return 0;
+
+exit_irq_fail:
+        close_candev(dev);
+exit_open_fail:
+        clk_disable_unprepare(priv->clk);
+        return err;
+}
+
+static void m_can_stop(struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+
+        /* disable all interrupts */
+        m_can_enable_all_interrupts(priv, false);
+
+        /* set the state as STOPPED */
+        priv->can.state = CAN_STATE_STOPPED;
+}
+
+
+static int m_can_close(struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+
+        netif_stop_queue(dev);
+        napi_disable(&priv->napi);
+        m_can_stop(dev);
+        free_irq(dev->irq, dev);
+        close_candev(dev);
+        can_led_event(dev, CAN_LED_EVENT_STOP);
+
+        return 0;
+}
+
+static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
+                                        struct net_device *dev)
+{
+        struct m_can_priv *priv = netdev_priv(dev);
+        struct can_frame *frame = (struct can_frame *)skb->data;
+        u32 flags = 0, id;
+
+        if (can_dropped_invalid_skb(dev, skb))
+                return NETDEV_TX_OK;
+
+        netif_stop_queue(dev);
+
+        if (frame->can_id & CAN_RTR_FLAG)
+                flags |= TX_BUF_RTR;
+
+        if (frame->can_id & CAN_EFF_FLAG) {
+                id = frame->can_id & CAN_EFF_MASK;
+                flags |= TX_BUF_XTD;
+        } else {
+                id = ((frame->can_id & CAN_SFF_MASK) << 18);
+        }
+
+        /* message ram configuration */
+        writel(id | flags,
+                priv->mram_base + priv->mram_off + priv->txb_off);
+        writel(frame->can_dlc << 16,
+                priv->mram_base + priv->mram_off + priv->txb_off + 0x4);
+        writel(*(u32 *)(frame->data + 0),
+                priv->mram_base + priv->mram_off + priv->txb_off + 0x8);
+        writel(*(u32 *)(frame->data + 4),
+                priv->mram_base + priv->mram_off + priv->txb_off + 0xc);
+
+        can_put_echo_skb(skb, dev, 0);
+
+        /* enable first TX buffer to start transfer  */
+        m_can_write(priv, M_CAN_TXBTIE, 0x00000001);
+        m_can_write(priv, M_CAN_TXBAR, 0x00000001);
+
+        return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops m_can_netdev_ops = {
+        .ndo_open = m_can_open,
+        .ndo_stop = m_can_close,
+        .ndo_start_xmit = m_can_start_xmit,
+};
+
+static int register_m_can_dev(struct net_device *dev)
+{
+        dev->flags |= IFF_ECHO; /* we support local echo */
+        dev->netdev_ops = &m_can_netdev_ops;
+
+        return register_candev(dev);
+}
+
+static const struct of_device_id m_can_of_table[] = {
+        { .compatible = "bosch,m_can", .data = NULL },
+        { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, m_can_of_table);
+
+static int m_can_of_parse_mram(struct platform_device *pdev,
+                                struct m_can_priv *priv)
+{
+        struct device_node *np = pdev->dev.of_node;
+        struct resource *res;
+        void __iomem *addr;
+        u32 out_val[8];
+        int ret;
+
+        /* message ram could be shared */
+        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram");
+        if (!res)
+                return -ENODEV;
+
+        addr = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+        if (!addr)
+                return -ENODEV;
+
+        /* get message ram configuration */
+        ret = of_property_read_u32_array(np, "mram-cfg",
+                                out_val, sizeof(out_val) / 4);
+        if (ret) {
+                dev_err(&pdev->dev, "can not get message ram configuration\n");
+                return -ENODEV;
+        }
+
+        priv->mram_base = addr;
+        priv->mram_off = out_val[0];
+        priv->sidf_elems = out_val[1];
+        priv->sidf_off = priv->mram_off;
+        priv->xidf_elems = out_val[2];
+        priv->xidf_off = priv->sidf_off + priv->sidf_elems * SIDF_ELEMENT_SIZE;
+        priv->rxf0_elems = out_val[3] & RXFC_FS_MASK;
+        priv->rxf0_off = priv->xidf_off + priv->xidf_elems * XIDF_ELEMENT_SIZE;
+        priv->rxf1_elems = out_val[4] & RXFC_FS_MASK;
+        priv->rxf1_off = priv->rxf0_off + priv->rxf0_elems * RXF0_ELEMENT_SIZE;
+        priv->rxb_elems = out_val[5];
+        priv->rxb_off = priv->rxf1_off + priv->rxf1_elems * RXF1_ELEMENT_SIZE;
+        priv->txe_elems = out_val[6];
+        priv->txe_off = priv->rxb_off + priv->rxb_elems * RXB_ELEMENT_SIZE;
+        priv->txb_elems = out_val[7] & TXBC_NDTB_MASK;
+        priv->txb_off = priv->txe_off + priv->txe_elems * TXE_ELEMENT_SIZE;
+
+        dev_dbg(&pdev->dev, "mram_base =%p mram_off =0x%x "
+                "sidf %d xidf %d rxf0 %d rxf1 %d rxb %d txe %d txb %d\n",
+                priv->mram_base, priv->mram_off, priv->sidf_elems,
+                priv->xidf_elems, priv->rxf0_elems, priv->rxf1_elems,
+                priv->rxb_elems, priv->txe_elems, priv->txb_elems);
+
+        return 0;
+}
+
+static int m_can_plat_probe(struct platform_device *pdev)
+{
+        struct net_device *dev;
+        struct m_can_priv *priv;
+        struct pinctrl *pinctrl;
+        struct resource *res;
+        void __iomem *addr;
+        struct clk *clk;
+        int irq, ret;
+
+        pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
+        if (IS_ERR(pinctrl))
+                dev_warn(&pdev->dev,
+                        "failed to configure pins from driver\n");
+
+        clk = devm_clk_get(&pdev->dev, NULL);
+        if (IS_ERR(clk)) {
+                dev_err(&pdev->dev, "no clock find\n");
+                return PTR_ERR(clk);
+        }
+
+        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "canfd");
+        addr = devm_request_and_ioremap(&pdev->dev, res);
+        irq = platform_get_irq(pdev, 0);
+        if (!addr || irq < 0)
+                return -EINVAL;
+
+        /* allocate the m_can device */
+        dev = alloc_m_can_dev();
+        if (!dev)
+                return -ENOMEM;
+
+        priv = netdev_priv(dev);
+        dev->irq = irq;
+        priv->base = addr;
+        priv->device = &pdev->dev;
+        priv->clk = clk;
+        priv->can.clock.freq = clk_get_rate(clk);
+
+        ret = m_can_of_parse_mram(pdev, priv);
+        if (ret)
+                goto failed_free_dev;
+
+        platform_set_drvdata(pdev, dev);
+        SET_NETDEV_DEV(dev, &pdev->dev);
+
+        ret = register_m_can_dev(dev);
+        if (ret) {
+                dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
+                        KBUILD_MODNAME, ret);
+                goto failed_free_dev;
+        }
+
+        devm_can_led_init(dev);
+
+        dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
+                 KBUILD_MODNAME, priv->base, dev->irq);
+
+        return 0;
+
+failed_free_dev:
+        free_m_can_dev(dev);
+        return ret;
+}
+
+#ifdef CONFIG_PM
+static int m_can_suspend(struct device *dev)
+{
+        struct net_device *ndev = dev_get_drvdata(dev);
+        struct m_can_priv *priv = netdev_priv(ndev);
+
+        if (netif_running(ndev)) {
+                netif_stop_queue(ndev);
+                netif_device_detach(ndev);
+        }
+
+        /* TODO: enter low power */
+
+        priv->can.state = CAN_STATE_SLEEPING;
+
+        return 0;
+}
+
+static int m_can_resume(struct device *dev)
+{
+        struct net_device *ndev = dev_get_drvdata(dev);
+        struct m_can_priv *priv = netdev_priv(ndev);
+
+        /* TODO: exit low power */
+
+        priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+        if (netif_running(ndev)) {
+                netif_device_attach(ndev);
+                netif_start_queue(ndev);
+        }
+
+        return 0;
+}
+#endif
+
+static void unregister_m_can_dev(struct net_device *dev)
+{
+        unregister_candev(dev);
+}
+
+static int m_can_plat_remove(struct platform_device *pdev)
+{
+        struct net_device *dev = platform_get_drvdata(pdev);
+
+        unregister_m_can_dev(dev);
+        platform_set_drvdata(pdev, NULL);
+
+        free_m_can_dev(dev);
+
+        return 0;
+}
+
+static const struct dev_pm_ops m_can_pmops = {
+        SET_SYSTEM_SLEEP_PM_OPS(m_can_suspend, m_can_resume)
+};
+
+static struct platform_driver m_can_plat_driver = {
+        .driver = {
+                .name = KBUILD_MODNAME,
+                .owner = THIS_MODULE,
+                .of_match_table = of_match_ptr(m_can_of_table),
+                .pm     = &m_can_pmops,
+        },
+        .probe = m_can_plat_probe,
+        .remove = m_can_plat_remove,
+};
+
+module_platform_driver(m_can_plat_driver);
+
+MODULE_AUTHOR("Dong Aisheng <b29396@freescale.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CAN bus driver for Bosch M_CAN controller");