diff options
Diffstat (limited to 'drivers/net/can/mcp251x.c')
| -rw-r--r-- | drivers/net/can/mcp251x.c | 1166 |
1 files changed, 1166 insertions, 0 deletions
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c new file mode 100644 index 0000000..78b1b69 --- /dev/null +++ b/drivers/net/can/mcp251x.c @@ -0,0 +1,1166 @@ +/* + * CAN bus driver for Microchip 251x CAN Controller with SPI Interface + * + * MCP2510 support and bug fixes by Christian Pellegrin + * <chripell@evolware.org> + * + * Copyright 2009 Christian Pellegrin EVOL S.r.l. + * + * Copyright 2007 Raymarine UK, Ltd. All Rights Reserved. + * Written under contract by: + * Chris Elston, Katalix Systems, Ltd. + * + * Based on Microchip MCP251x CAN controller driver written by + * David Vrabel, Copyright 2006 Arcom Control Systems Ltd. + * + * Based on CAN bus driver for the CCAN controller written by + * - Sascha Hauer, Marc Kleine-Budde, Pengutronix + * - Simon Kallweit, intefo AG + * Copyright 2007 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the version 2 of the GNU General Public License + * as published by the Free Software Foundation + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * + * + * Your platform definition file should specify something like: + * + * static struct mcp251x_platform_data mcp251x_info = { + * .oscillator_frequency = 8000000, + * .board_specific_setup = &mcp251x_setup, + * .model = CAN_MCP251X_MCP2510, + * .power_enable = mcp251x_power_enable, + * .transceiver_enable = NULL, + * }; + * + * static struct spi_board_info spi_board_info[] = { + * { + * .modalias = "mcp251x", + * .platform_data = &mcp251x_info, + * .irq = IRQ_EINT13, + * .max_speed_hz = 2*1000*1000, + * .chip_select = 2, + * }, + * }; + * + * Please see mcp251x.h for a description of the fields in + * struct mcp251x_platform_data. + * + */ + +#include <linux/can.h> +#include <linux/can/core.h> +#include <linux/can/dev.h> +#include <linux/can/platform/mcp251x.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/dma-mapping.h> +#include <linux/freezer.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/uaccess.h> + +/* SPI interface instruction set */ +#define INSTRUCTION_WRITE 0x02 +#define INSTRUCTION_READ 0x03 +#define INSTRUCTION_BIT_MODIFY 0x05 +#define INSTRUCTION_LOAD_TXB(n) (0x40 + 2 * (n)) +#define INSTRUCTION_READ_RXB(n) (((n) == 0) ? 0x90 : 0x94) +#define INSTRUCTION_RESET 0xC0 + +/* MPC251x registers */ +#define CANSTAT 0x0e +#define CANCTRL 0x0f +# define CANCTRL_REQOP_MASK 0xe0 +# define CANCTRL_REQOP_CONF 0x80 +# define CANCTRL_REQOP_LISTEN_ONLY 0x60 +# define CANCTRL_REQOP_LOOPBACK 0x40 +# define CANCTRL_REQOP_SLEEP 0x20 +# define CANCTRL_REQOP_NORMAL 0x00 +# define CANCTRL_OSM 0x08 +# define CANCTRL_ABAT 0x10 +#define TEC 0x1c +#define REC 0x1d +#define CNF1 0x2a +# define CNF1_SJW_SHIFT 6 +#define CNF2 0x29 +# define CNF2_BTLMODE 0x80 +# define CNF2_SAM 0x40 +# define CNF2_PS1_SHIFT 3 +#define CNF3 0x28 +# define CNF3_SOF 0x08 +# define CNF3_WAKFIL 0x04 +# define CNF3_PHSEG2_MASK 0x07 +#define CANINTE 0x2b +# define CANINTE_MERRE 0x80 +# define CANINTE_WAKIE 0x40 +# define CANINTE_ERRIE 0x20 +# define CANINTE_TX2IE 0x10 +# define CANINTE_TX1IE 0x08 +# define CANINTE_TX0IE 0x04 +# define CANINTE_RX1IE 0x02 +# define CANINTE_RX0IE 0x01 +#define CANINTF 0x2c +# define CANINTF_MERRF 0x80 +# define CANINTF_WAKIF 0x40 +# define CANINTF_ERRIF 0x20 +# define CANINTF_TX2IF 0x10 +# define CANINTF_TX1IF 0x08 +# define CANINTF_TX0IF 0x04 +# define CANINTF_RX1IF 0x02 +# define CANINTF_RX0IF 0x01 +#define EFLG 0x2d +# define EFLG_EWARN 0x01 +# define EFLG_RXWAR 0x02 +# define EFLG_TXWAR 0x04 +# define EFLG_RXEP 0x08 +# define EFLG_TXEP 0x10 +# define EFLG_TXBO 0x20 +# define EFLG_RX0OVR 0x40 +# define EFLG_RX1OVR 0x80 +#define TXBCTRL(n) (((n) * 0x10) + 0x30 + TXBCTRL_OFF) +# define TXBCTRL_ABTF 0x40 +# define TXBCTRL_MLOA 0x20 +# define TXBCTRL_TXERR 0x10 +# define TXBCTRL_TXREQ 0x08 +#define TXBSIDH(n) (((n) * 0x10) + 0x30 + TXBSIDH_OFF) +# define SIDH_SHIFT 3 +#define TXBSIDL(n) (((n) * 0x10) + 0x30 + TXBSIDL_OFF) +# define SIDL_SID_MASK 7 +# define SIDL_SID_SHIFT 5 +# define SIDL_EXIDE_SHIFT 3 +# define SIDL_EID_SHIFT 16 +# define SIDL_EID_MASK 3 +#define TXBEID8(n) (((n) * 0x10) + 0x30 + TXBEID8_OFF) +#define TXBEID0(n) (((n) * 0x10) + 0x30 + TXBEID0_OFF) +#define TXBDLC(n) (((n) * 0x10) + 0x30 + TXBDLC_OFF) +# define DLC_RTR_SHIFT 6 +#define TXBCTRL_OFF 0 +#define TXBSIDH_OFF 1 +#define TXBSIDL_OFF 2 +#define TXBEID8_OFF 3 +#define TXBEID0_OFF 4 +#define TXBDLC_OFF 5 +#define TXBDAT_OFF 6 +#define RXBCTRL(n) (((n) * 0x10) + 0x60 + RXBCTRL_OFF) +# define RXBCTRL_BUKT 0x04 +# define RXBCTRL_RXM0 0x20 +# define RXBCTRL_RXM1 0x40 +#define RXBSIDH(n) (((n) * 0x10) + 0x60 + RXBSIDH_OFF) +# define RXBSIDH_SHIFT 3 +#define RXBSIDL(n) (((n) * 0x10) + 0x60 + RXBSIDL_OFF) +# define RXBSIDL_IDE 0x08 +# define RXBSIDL_EID 3 +# define RXBSIDL_SHIFT 5 +#define RXBEID8(n) (((n) * 0x10) + 0x60 + RXBEID8_OFF) +#define RXBEID0(n) (((n) * 0x10) + 0x60 + RXBEID0_OFF) +#define RXBDLC(n) (((n) * 0x10) + 0x60 + RXBDLC_OFF) +# define RXBDLC_LEN_MASK 0x0f +# define RXBDLC_RTR 0x40 +#define RXBCTRL_OFF 0 +#define RXBSIDH_OFF 1 +#define RXBSIDL_OFF 2 +#define RXBEID8_OFF 3 +#define RXBEID0_OFF 4 +#define RXBDLC_OFF 5 +#define RXBDAT_OFF 6 + +#define GET_BYTE(val, byte) \ + (((val) >> ((byte) * 8)) & 0xff) +#define SET_BYTE(val, byte) \ + (((val) & 0xff) << ((byte) * 8)) + +/* + * Buffer size required for the largest SPI transfer (i.e., reading a + * frame) + */ +#define CAN_FRAME_MAX_DATA_LEN 8 +#define SPI_TRANSFER_BUF_LEN (6 + CAN_FRAME_MAX_DATA_LEN) +#define CAN_FRAME_MAX_BITS 128 + +#define TX_ECHO_SKB_MAX 1 + +#define DEVICE_NAME "mcp251x" + +static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */ +module_param(mcp251x_enable_dma, int, S_IRUGO); +MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)"); + +static struct can_bittiming_const mcp251x_bittiming_const = { + .name = DEVICE_NAME, + .tseg1_min = 3, + .tseg1_max = 16, + .tseg2_min = 2, + .tseg2_max = 8, + .sjw_max = 4, + .brp_min = 1, + .brp_max = 64, + .brp_inc = 1, +}; + +struct mcp251x_priv { + struct can_priv can; + struct net_device *net; + struct spi_device *spi; + + struct mutex spi_lock; /* SPI buffer lock */ + u8 *spi_tx_buf; + u8 *spi_rx_buf; + dma_addr_t spi_tx_dma; + dma_addr_t spi_rx_dma; + + struct sk_buff *tx_skb; + int tx_len; + struct workqueue_struct *wq; + struct work_struct tx_work; + struct work_struct irq_work; + struct completion awake; + int wake; + int force_quit; + int after_suspend; +#define AFTER_SUSPEND_UP 1 +#define AFTER_SUSPEND_DOWN 2 +#define AFTER_SUSPEND_POWER 4 +#define AFTER_SUSPEND_RESTART 8 + int restart_tx; +}; + +static void mcp251x_clean(struct net_device *net) +{ + struct mcp251x_priv *priv = netdev_priv(net); + + net->stats.tx_errors++; + if (priv->tx_skb) + dev_kfree_skb(priv->tx_skb); + if (priv->tx_len) + can_free_echo_skb(priv->net, 0); + priv->tx_skb = NULL; + priv->tx_len = 0; +} + +/* + * Note about handling of error return of mcp251x_spi_trans: accessing + * registers via SPI is not really different conceptually than using + * normal I/O assembler instructions, although it's much more + * complicated from a practical POV. So it's not advisable to always + * check the return value of this function. Imagine that every + * read{b,l}, write{b,l} and friends would be bracketed in "if ( < 0) + * error();", it would be a great mess (well there are some situation + * when exception handling C++ like could be useful after all). So we + * just check that transfers are OK at the beginning of our + * conversation with the chip and to avoid doing really nasty things + * (like injecting bogus packets in the network stack). + */ +static int mcp251x_spi_trans(struct spi_device *spi, int len) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + struct spi_transfer t = { + .tx_buf = priv->spi_tx_buf, + .rx_buf = priv->spi_rx_buf, + .len = len, + .cs_change = 0, + }; + struct spi_message m; + int ret; + + spi_message_init(&m); + + if (mcp251x_enable_dma) { + t.tx_dma = priv->spi_tx_dma; + t.rx_dma = priv->spi_rx_dma; + m.is_dma_mapped = 1; + } + + spi_message_add_tail(&t, &m); + + ret = spi_sync(spi, &m); + if (ret) + dev_err(&spi->dev, "spi transfer failed: ret = %d\n", ret); + return ret; +} + +static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + u8 val = 0; + + mutex_lock(&priv->spi_lock); + + priv->spi_tx_buf[0] = INSTRUCTION_READ; + priv->spi_tx_buf[1] = reg; + + mcp251x_spi_trans(spi, 3); + val = priv->spi_rx_buf[2]; + + mutex_unlock(&priv->spi_lock); + + return val; +} + +static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + mutex_lock(&priv->spi_lock); + + priv->spi_tx_buf[0] = INSTRUCTION_WRITE; + priv->spi_tx_buf[1] = reg; + priv->spi_tx_buf[2] = val; + + mcp251x_spi_trans(spi, 3); + + mutex_unlock(&priv->spi_lock); +} + +static void mcp251x_write_bits(struct spi_device *spi, u8 reg, + u8 mask, uint8_t val) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + mutex_lock(&priv->spi_lock); + + priv->spi_tx_buf[0] = INSTRUCTION_BIT_MODIFY; + priv->spi_tx_buf[1] = reg; + priv->spi_tx_buf[2] = mask; + priv->spi_tx_buf[3] = val; + + mcp251x_spi_trans(spi, 4); + + mutex_unlock(&priv->spi_lock); +} + +static void mcp251x_hw_tx_frame(struct spi_device *spi, u8 *buf, + int len, int tx_buf_idx) +{ + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + if (pdata->model == CAN_MCP251X_MCP2510) { + int i; + + for (i = 1; i < TXBDAT_OFF + len; i++) + mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx) + i, + buf[i]); + } else { + mutex_lock(&priv->spi_lock); + memcpy(priv->spi_tx_buf, buf, TXBDAT_OFF + len); + mcp251x_spi_trans(spi, TXBDAT_OFF + len); + mutex_unlock(&priv->spi_lock); + } +} + +static void mcp251x_hw_tx(struct spi_device *spi, struct can_frame *frame, + int tx_buf_idx) +{ + u32 sid, eid, exide, rtr; + u8 buf[SPI_TRANSFER_BUF_LEN]; + + exide = (frame->can_id & CAN_EFF_FLAG) ? 1 : 0; /* Extended ID Enable */ + if (exide) + sid = (frame->can_id & CAN_EFF_MASK) >> 18; + else + sid = frame->can_id & CAN_SFF_MASK; /* Standard ID */ + eid = frame->can_id & CAN_EFF_MASK; /* Extended ID */ + rtr = (frame->can_id & CAN_RTR_FLAG) ? 1 : 0; /* Remote transmission */ + + buf[TXBCTRL_OFF] = INSTRUCTION_LOAD_TXB(tx_buf_idx); + buf[TXBSIDH_OFF] = sid >> SIDH_SHIFT; + buf[TXBSIDL_OFF] = ((sid & SIDL_SID_MASK) << SIDL_SID_SHIFT) | + (exide << SIDL_EXIDE_SHIFT) | + ((eid >> SIDL_EID_SHIFT) & SIDL_EID_MASK); + buf[TXBEID8_OFF] = GET_BYTE(eid, 1); + buf[TXBEID0_OFF] = GET_BYTE(eid, 0); + buf[TXBDLC_OFF] = (rtr << DLC_RTR_SHIFT) | frame->can_dlc; + memcpy(buf + TXBDAT_OFF, frame->data, frame->can_dlc); + mcp251x_hw_tx_frame(spi, buf, frame->can_dlc, tx_buf_idx); + mcp251x_write_reg(spi, TXBCTRL(tx_buf_idx), TXBCTRL_TXREQ); +} + +static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf, + int buf_idx) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + + if (pdata->model == CAN_MCP251X_MCP2510) { + int i, len; + + for (i = 1; i < RXBDAT_OFF; i++) + buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); + len = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK; + if (len > 8) + len = 8; + for (; i < (RXBDAT_OFF + len); i++) + buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); + } else { + mutex_lock(&priv->spi_lock); + + priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx); + mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN); + memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN); + + mutex_unlock(&priv->spi_lock); + } +} + +static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + struct sk_buff *skb; + struct can_frame *frame; + u8 buf[SPI_TRANSFER_BUF_LEN]; + + skb = alloc_can_skb(priv->net, &frame); + if (!skb) { + dev_err(&spi->dev, "cannot allocate RX skb\n"); + priv->net->stats.rx_dropped++; + return; + } + + mcp251x_hw_rx_frame(spi, buf, buf_idx); + if (buf[RXBSIDL_OFF] & RXBSIDL_IDE) { + /* Extended ID format */ + frame->can_id = CAN_EFF_FLAG; + frame->can_id |= + /* Extended ID part */ + SET_BYTE(buf[RXBSIDL_OFF] & RXBSIDL_EID, 2) | + SET_BYTE(buf[RXBEID8_OFF], 1) | + SET_BYTE(buf[RXBEID0_OFF], 0) | + /* Standard ID part */ + (((buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) | + (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT)) << 18); + /* Remote transmission request */ + if (buf[RXBDLC_OFF] & RXBDLC_RTR) + frame->can_id |= CAN_RTR_FLAG; + } else { + /* Standard ID format */ + frame->can_id = + (buf[RXBSIDH_OFF] << RXBSIDH_SHIFT) | + (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT); + } + /* Data length */ + frame->can_dlc = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK; + if (frame->can_dlc > 8) { + dev_warn(&spi->dev, "invalid frame recevied\n"); + priv->net->stats.rx_errors++; + dev_kfree_skb(skb); + return; + } + memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc); + + priv->net->stats.rx_packets++; + priv->net->stats.rx_bytes += frame->can_dlc; + netif_rx(skb); +} + +static void mcp251x_hw_sleep(struct spi_device *spi) +{ + mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_SLEEP); +} + +static void mcp251x_hw_wakeup(struct spi_device *spi) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + priv->wake = 1; + + /* Can only wake up by generating a wake-up interrupt. */ + mcp251x_write_bits(spi, CANINTE, CANINTE_WAKIE, CANINTE_WAKIE); + mcp251x_write_bits(spi, CANINTF, CANINTF_WAKIF, CANINTF_WAKIF); + + /* Wait until the device is awake */ + if (!wait_for_completion_timeout(&priv->awake, HZ)) + dev_err(&spi->dev, "MCP251x didn't wake-up\n"); +} + +static netdev_tx_t mcp251x_hard_start_xmit(struct sk_buff *skb, + struct net_device *net) +{ + struct mcp251x_priv *priv = netdev_priv(net); + struct spi_device *spi = priv->spi; + + if (priv->tx_skb || priv->tx_len) { + dev_warn(&spi->dev, "hard_xmit called while tx busy\n"); + netif_stop_queue(net); + return NETDEV_TX_BUSY; + } + + if (skb->len != sizeof(struct can_frame)) { + dev_err(&spi->dev, "dropping packet - bad length\n"); + dev_kfree_skb(skb); + net->stats.tx_dropped++; + return NETDEV_TX_OK; + } + + netif_stop_queue(net); + priv->tx_skb = skb; + net->trans_start = jiffies; + queue_work(priv->wq, &priv->tx_work); + + return NETDEV_TX_OK; +} + +static int mcp251x_do_set_mode(struct net_device *net, enum can_mode mode) +{ + struct mcp251x_priv *priv = netdev_priv(net); + + switch (mode) { + case CAN_MODE_START: + /* We have to delay work since SPI I/O may sleep */ + priv->can.state = CAN_STATE_ERROR_ACTIVE; + priv->restart_tx = 1; + if (priv->can.restart_ms == 0) + priv->after_suspend = AFTER_SUSPEND_RESTART; + queue_work(priv->wq, &priv->irq_work); + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static void mcp251x_set_normal_mode(struct spi_device *spi) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + unsigned long timeout; + + /* Enable interrupts */ + mcp251x_write_reg(spi, CANINTE, + CANINTE_ERRIE | CANINTE_TX2IE | CANINTE_TX1IE | + CANINTE_TX0IE | CANINTE_RX1IE | CANINTE_RX0IE | + CANINTF_MERRF); + + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) { + /* Put device into loopback mode */ + mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_LOOPBACK); + } else { + /* Put device into normal mode */ + mcp251x_write_reg(spi, CANCTRL, CANCTRL_REQOP_NORMAL); + + /* Wait for the device to enter normal mode */ + timeout = jiffies + HZ; + while (mcp251x_read_reg(spi, CANSTAT) & CANCTRL_REQOP_MASK) { + schedule(); + if (time_after(jiffies, timeout)) { + dev_err(&spi->dev, "MCP251x didn't" + " enter in normal mode\n"); + return; + } + } + } + priv->can.state = CAN_STATE_ERROR_ACTIVE; +} + +static int mcp251x_do_set_bittiming(struct net_device *net) +{ + struct mcp251x_priv *priv = netdev_priv(net); + struct can_bittiming *bt = &priv->can.bittiming; + struct spi_device *spi = priv->spi; + + mcp251x_write_reg(spi, CNF1, ((bt->sjw - 1) << CNF1_SJW_SHIFT) | + (bt->brp - 1)); + mcp251x_write_reg(spi, CNF2, CNF2_BTLMODE | + (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES ? + CNF2_SAM : 0) | + ((bt->phase_seg1 - 1) << CNF2_PS1_SHIFT) | + (bt->prop_seg - 1)); + mcp251x_write_bits(spi, CNF3, CNF3_PHSEG2_MASK, + (bt->phase_seg2 - 1)); + dev_info(&spi->dev, "CNF: 0x%02x 0x%02x 0x%02x\n", + mcp251x_read_reg(spi, CNF1), + mcp251x_read_reg(spi, CNF2), + mcp251x_read_reg(spi, CNF3)); + + return 0; +} + +static int mcp251x_setup(struct net_device *net, struct mcp251x_priv *priv, + struct spi_device *spi) +{ + mcp251x_do_set_bittiming(net); + + /* Enable RX0->RX1 buffer roll over and disable filters */ + mcp251x_write_bits(spi, RXBCTRL(0), + RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1, + RXBCTRL_BUKT | RXBCTRL_RXM0 | RXBCTRL_RXM1); + mcp251x_write_bits(spi, RXBCTRL(1), + RXBCTRL_RXM0 | RXBCTRL_RXM1, + RXBCTRL_RXM0 | RXBCTRL_RXM1); + return 0; +} + +static void mcp251x_hw_reset(struct spi_device *spi) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + int ret; + + mutex_lock(&priv->spi_lock); + + priv->spi_tx_buf[0] = INSTRUCTION_RESET; + + ret = spi_write(spi, priv->spi_tx_buf, 1); + + mutex_unlock(&priv->spi_lock); + + if (ret) + dev_err(&spi->dev, "reset failed: ret = %d\n", ret); + /* Wait for reset to finish */ + mdelay(10); +} + +static int mcp251x_hw_probe(struct spi_device *spi) +{ + int st1, st2; + + mcp251x_hw_reset(spi); + + /* + * Please note that these are "magic values" based on after + * reset defaults taken from data sheet which allows us to see + * if we really have a chip on the bus (we avoid common all + * zeroes or all ones situations) + */ + st1 = mcp251x_read_reg(spi, CANSTAT) & 0xEE; + st2 = mcp251x_read_reg(spi, CANCTRL) & 0x17; + + dev_dbg(&spi->dev, "CANSTAT 0x%02x CANCTRL 0x%02x\n", st1, st2); + + /* Check for power up default values */ + return (st1 == 0x80 && st2 == 0x07) ? 1 : 0; +} + +static irqreturn_t mcp251x_can_isr(int irq, void *dev_id) +{ + struct net_device *net = (struct net_device *)dev_id; + struct mcp251x_priv *priv = netdev_priv(net); + + /* Schedule bottom half */ + if (!work_pending(&priv->irq_work)) + queue_work(priv->wq, &priv->irq_work); + + return IRQ_HANDLED; +} + +static int mcp251x_open(struct net_device *net) +{ + struct mcp251x_priv *priv = netdev_priv(net); + struct spi_device *spi = priv->spi; + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + int ret; + + ret = open_candev(net); + if (ret) { + dev_err(&spi->dev, "unable to set initial baudrate!\n"); + return ret; + } + + if (pdata->transceiver_enable) + pdata->transceiver_enable(1); + + priv->force_quit = 0; + priv->tx_skb = NULL; + priv->tx_len = 0; + + ret = request_irq(spi->irq, mcp251x_can_isr, + IRQF_TRIGGER_FALLING, DEVICE_NAME, net); + if (ret) { + dev_err(&spi->dev, "failed to acquire irq %d\n", spi->irq); + if (pdata->transceiver_enable) + pdata->transceiver_enable(0); + close_candev(net); + return ret; + } + + mcp251x_hw_wakeup(spi); + mcp251x_hw_reset(spi); + ret = mcp251x_setup(net, priv, spi); + if (ret) { + free_irq(spi->irq, net); + mcp251x_hw_sleep(spi); + if (pdata->transceiver_enable) + pdata->transceiver_enable(0); + close_candev(net); + return ret; + } + mcp251x_set_normal_mode(spi); + netif_wake_queue(net); + + return 0; +} + +static int mcp251x_stop(struct net_device *net) +{ + struct mcp251x_priv *priv = netdev_priv(net); + struct spi_device *spi = priv->spi; + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + + close_candev(net); + + /* Disable and clear pending interrupts */ + mcp251x_write_reg(spi, CANINTE, 0x00); + mcp251x_write_reg(spi, CANINTF, 0x00); + + priv->force_quit = 1; + free_irq(spi->irq, net); + flush_workqueue(priv->wq); + + mcp251x_write_reg(spi, TXBCTRL(0), 0); + if (priv->tx_skb || priv->tx_len) + mcp251x_clean(net); + + mcp251x_hw_sleep(spi); + + if (pdata->transceiver_enable) + pdata->transceiver_enable(0); + + priv->can.state = CAN_STATE_STOPPED; + + return 0; +} + +static void mcp251x_tx_work_handler(struct work_struct *ws) +{ + struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv, + tx_work); + struct spi_device *spi = priv->spi; + struct net_device *net = priv->net; + struct can_frame *frame; + + if (priv->tx_skb) { + frame = (struct can_frame *)priv->tx_skb->data; + + if (priv->can.state == CAN_STATE_BUS_OFF) { + mcp251x_clean(net); + netif_wake_queue(net); + return; + } + if (frame->can_dlc > CAN_FRAME_MAX_DATA_LEN) + frame->can_dlc = CAN_FRAME_MAX_DATA_LEN; + mcp251x_hw_tx(spi, frame, 0); + priv->tx_len = 1 + frame->can_dlc; + can_put_echo_skb(priv->tx_skb, net, 0); + priv->tx_skb = NULL; + } +} + +static void mcp251x_irq_work_handler(struct work_struct *ws) +{ + struct mcp251x_priv *priv = container_of(ws, struct mcp251x_priv, + irq_work); + struct spi_device *spi = priv->spi; + struct net_device *net = priv->net; + u8 txbnctrl; + u8 intf; + enum can_state new_state; + + if (priv->after_suspend) { + mdelay(10); + mcp251x_hw_reset(spi); + mcp251x_setup(net, priv, spi); + if (priv->after_suspend & AFTER_SUSPEND_RESTART) { + mcp251x_set_normal_mode(spi); + } else if (priv->after_suspend & AFTER_SUSPEND_UP) { + netif_device_attach(net); + /* Clean since we lost tx buffer */ + if (priv->tx_skb || priv->tx_len) { + mcp251x_clean(net); + netif_wake_queue(net); + } + mcp251x_set_normal_mode(spi); + } else { + mcp251x_hw_sleep(spi); + } + priv->after_suspend = 0; + } + + if (priv->can.restart_ms == 0 && priv->can.state == CAN_STATE_BUS_OFF) + return; + + while (!priv->force_quit && !freezing(current)) { + u8 eflag = mcp251x_read_reg(spi, EFLG); + int can_id = 0, data1 = 0; + + mcp251x_write_reg(spi, EFLG, 0x00); + + if (priv->restart_tx) { + priv->restart_tx = 0; + mcp251x_write_reg(spi, TXBCTRL(0), 0); + if (priv->tx_skb || priv->tx_len) + mcp251x_clean(net); + netif_wake_queue(net); + can_id |= CAN_ERR_RESTARTED; + } + + if (priv->wake) { + /* Wait whilst the device wakes up */ + mdelay(10); + priv->wake = 0; + } + + intf = mcp251x_read_reg(spi, CANINTF); + mcp251x_write_bits(spi, CANINTF, intf, 0x00); + + /* Update can state */ + if (eflag & EFLG_TXBO) { + new_state = CAN_STATE_BUS_OFF; + can_id |= CAN_ERR_BUSOFF; + } else if (eflag & EFLG_TXEP) { + new_state = CAN_STATE_ERROR_PASSIVE; + can_id |= CAN_ERR_CRTL; + data1 |= CAN_ERR_CRTL_TX_PASSIVE; + } else if (eflag & EFLG_RXEP) { + new_state = CAN_STATE_ERROR_PASSIVE; + can_id |= CAN_ERR_CRTL; + data1 |= CAN_ERR_CRTL_RX_PASSIVE; + } else if (eflag & EFLG_TXWAR) { + new_state = CAN_STATE_ERROR_WARNING; + can_id |= CAN_ERR_CRTL; + data1 |= CAN_ERR_CRTL_TX_WARNING; + } else if (eflag & EFLG_RXWAR) { + new_state = CAN_STATE_ERROR_WARNING; + can_id |= CAN_ERR_CRTL; + data1 |= CAN_ERR_CRTL_RX_WARNING; + } else { + new_state = CAN_STATE_ERROR_ACTIVE; + } + + /* Update can state statistics */ + switch (priv->can.state) { + case CAN_STATE_ERROR_ACTIVE: + if (new_state >= CAN_STATE_ERROR_WARNING && + new_state <= CAN_STATE_BUS_OFF) + priv->can.can_stats.error_warning++; + case CAN_STATE_ERROR_WARNING: /* fallthrough */ + if (new_state >= CAN_STATE_ERROR_PASSIVE && + new_state <= CAN_STATE_BUS_OFF) + priv->can.can_stats.error_passive++; + break; + default: + break; + } + priv->can.state = new_state; + + if ((intf & CANINTF_ERRIF) || (can_id & CAN_ERR_RESTARTED)) { + struct sk_buff *skb; + struct can_frame *frame; + + /* Create error frame */ + skb = alloc_can_err_skb(net, &frame); + if (skb) { + /* Set error frame flags based on bus state */ + frame->can_id = can_id; + frame->data[1] = data1; + + /* Update net stats for overflows */ + if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR)) { + if (eflag & EFLG_RX0OVR) + net->stats.rx_over_errors++; + if (eflag & EFLG_RX1OVR) + net->stats.rx_over_errors++; + frame->can_id |= CAN_ERR_CRTL; + frame->data[1] |= + CAN_ERR_CRTL_RX_OVERFLOW; + } + + netif_rx(skb); + } else { + dev_info(&spi->dev, + "cannot allocate error skb\n"); + } + } + + if (priv->can.state == CAN_STATE_BUS_OFF) { + if (priv->can.restart_ms == 0) { + can_bus_off(net); + mcp251x_hw_sleep(spi); + return; + } + } + + if (intf == 0) + break; + + if (intf & CANINTF_WAKIF) + complete(&priv->awake); + + if (intf & CANINTF_MERRF) { + /* If there are pending Tx buffers, restart queue */ + txbnctrl = mcp251x_read_reg(spi, TXBCTRL(0)); + if (!(txbnctrl & TXBCTRL_TXREQ)) { + if (priv->tx_skb || priv->tx_len) + mcp251x_clean(net); + netif_wake_queue(net); + } + } + + if (intf & (CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF)) { + net->stats.tx_packets++; + net->stats.tx_bytes += priv->tx_len - 1; + if (priv->tx_len) { + can_get_echo_skb(net, 0); + priv->tx_len = 0; + } + netif_wake_queue(net); + } + + if (intf & CANINTF_RX0IF) + mcp251x_hw_rx(spi, 0); + + if (intf & CANINTF_RX1IF) + mcp251x_hw_rx(spi, 1); + } +} + +static const struct net_device_ops mcp251x_netdev_ops = { + .ndo_open = mcp251x_open, + .ndo_stop = mcp251x_stop, + .ndo_start_xmit = mcp251x_hard_start_xmit, +}; + +static int __devinit mcp251x_can_probe(struct spi_device *spi) +{ + struct net_device *net; + struct mcp251x_priv *priv; + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + int ret = -ENODEV; + + if (!pdata) + /* Platform data is required for osc freq */ + goto error_out; + + /* Allocate can/net device */ + net = alloc_candev(sizeof(struct mcp251x_priv), TX_ECHO_SKB_MAX); + if (!net) { + ret = -ENOMEM; + goto error_alloc; + } + + net->netdev_ops = &mcp251x_netdev_ops; + net->flags |= IFF_ECHO; + + priv = netdev_priv(net); + priv->can.bittiming_const = &mcp251x_bittiming_const; + priv->can.do_set_mode = mcp251x_do_set_mode; + priv->can.clock.freq = pdata->oscillator_frequency / 2; + priv->net = net; + dev_set_drvdata(&spi->dev, priv); + + priv->spi = spi; + mutex_init(&priv->spi_lock); + + /* If requested, allocate DMA buffers */ + if (mcp251x_enable_dma) { + spi->dev.coherent_dma_mask = ~0; + + /* + * Minimum coherent DMA allocation is PAGE_SIZE, so allocate + * that much and share it between Tx and Rx DMA buffers. + */ + priv->spi_tx_buf = dma_alloc_coherent(&spi->dev, + PAGE_SIZE, + &priv->spi_tx_dma, + GFP_DMA); + + if (priv->spi_tx_buf) { + priv->spi_rx_buf = (u8 *)(priv->spi_tx_buf + + (PAGE_SIZE / 2)); + priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma + + (PAGE_SIZE / 2)); + } else { + /* Fall back to non-DMA */ + mcp251x_enable_dma = 0; + } + } + + /* Allocate non-DMA buffers */ + if (!mcp251x_enable_dma) { + priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL); + if (!priv->spi_tx_buf) { + ret = -ENOMEM; + goto error_tx_buf; + } + priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL); + if (!priv->spi_tx_buf) { + ret = -ENOMEM; + goto error_rx_buf; + } + } + + if (pdata->power_enable) + pdata->power_enable(1); + + /* Call out to platform specific setup */ + if (pdata->board_specific_setup) + pdata->board_specific_setup(spi); + + SET_NETDEV_DEV(net, &spi->dev); + + priv->wq = create_freezeable_workqueue("mcp251x_wq"); + + INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler); + INIT_WORK(&priv->irq_work, mcp251x_irq_work_handler); + + init_completion(&priv->awake); + + /* Configure the SPI bus */ + spi->mode = SPI_MODE_0; + spi->bits_per_word = 8; + spi_setup(spi); + + if (!mcp251x_hw_probe(spi)) { + dev_info(&spi->dev, "Probe failed\n"); + goto error_probe; + } + mcp251x_hw_sleep(spi); + + if (pdata->transceiver_enable) + pdata->transceiver_enable(0); + + ret = register_candev(net); + if (!ret) { + dev_info(&spi->dev, "probed\n"); + return ret; + } +error_probe: + if (!mcp251x_enable_dma) + kfree(priv->spi_rx_buf); +error_rx_buf: + if (!mcp251x_enable_dma) + kfree(priv->spi_tx_buf); +error_tx_buf: + free_candev(net); + if (mcp251x_enable_dma) + dma_free_coherent(&spi->dev, PAGE_SIZE, + priv->spi_tx_buf, priv->spi_tx_dma); +error_alloc: + if (pdata->power_enable) + pdata->power_enable(0); + dev_err(&spi->dev, "probe failed\n"); +error_out: + return ret; +} + +static int __devexit mcp251x_can_remove(struct spi_device *spi) +{ + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + struct net_device *net = priv->net; + + unregister_candev(net); + free_candev(net); + + priv->force_quit = 1; + flush_workqueue(priv->wq); + destroy_workqueue(priv->wq); + + if (mcp251x_enable_dma) { + dma_free_coherent(&spi->dev, PAGE_SIZE, + priv->spi_tx_buf, priv->spi_tx_dma); + } else { + kfree(priv->spi_tx_buf); + kfree(priv->spi_rx_buf); + } + + if (pdata->power_enable) + pdata->power_enable(0); + + return 0; +} + +#ifdef CONFIG_PM +static int mcp251x_can_suspend(struct spi_device *spi, pm_message_t state) +{ + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + struct net_device *net = priv->net; + + if (netif_running(net)) { + netif_device_detach(net); + + mcp251x_hw_sleep(spi); + if (pdata->transceiver_enable) + pdata->transceiver_enable(0); + priv->after_suspend = AFTER_SUSPEND_UP; + } else { + priv->after_suspend = AFTER_SUSPEND_DOWN; + } + + if (pdata->power_enable) { + pdata->power_enable(0); + priv->after_suspend |= AFTER_SUSPEND_POWER; + } + + return 0; +} + +static int mcp251x_can_resume(struct spi_device *spi) +{ + struct mcp251x_platform_data *pdata = spi->dev.platform_data; + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + if (priv->after_suspend & AFTER_SUSPEND_POWER) { + pdata->power_enable(1); + queue_work(priv->wq, &priv->irq_work); + } else { + if (priv->after_suspend & AFTER_SUSPEND_UP) { + if (pdata->transceiver_enable) + pdata->transceiver_enable(1); + queue_work(priv->wq, &priv->irq_work); + } else { + priv->after_suspend = 0; + } + } + return 0; +} +#else +#define mcp251x_can_suspend NULL +#define mcp251x_can_resume NULL +#endif + +static struct spi_driver mcp251x_can_driver = { + .driver = { + .name = DEVICE_NAME, + .bus = &spi_bus_type, + .owner = THIS_MODULE, + }, + + .probe = mcp251x_can_probe, + .remove = __devexit_p(mcp251x_can_remove), + .suspend = mcp251x_can_suspend, + .resume = mcp251x_can_resume, +}; + +static int __init mcp251x_can_init(void) +{ + return spi_register_driver(&mcp251x_can_driver); +} + +static void __exit mcp251x_can_exit(void) +{ + spi_unregister_driver(&mcp251x_can_driver); +} + +module_init(mcp251x_can_init); +module_exit(mcp251x_can_exit); + +MODULE_AUTHOR("Chris Elston <celston@katalix.com>, " + "Christian Pellegrin <chripell@evolware.org>"); +MODULE_DESCRIPTION("Microchip 251x CAN driver"); +MODULE_LICENSE("GPL v2"); |
