Message-ID: <3c17e3570912100214k4b3eb038u1108c82bfa346389@mail.gmail.com>
Date:	Thu, 10 Dec 2009 18:14:24 +0800
From:	Barry Song <21cnbao@...il.com>
To:	Wolfgang Grandegger <wg@...ndegger.com>
Cc:	davem@...emloft.net, socketcan-core@...ts.berlios.de,
	uclinux-dist-devel@...ckfin.uclinux.org, netdev@...r.kernel.org,
	"H.J. Oertel" <oe@...t.de>
Subject: Re: [PATCH v3] add the driver for Analog Devices Blackfin on-chip CAN 
	controllers

On Thu, Dec 10, 2009 at 5:11 PM, Wolfgang Grandegger <wg@...ndegger.com> wrote:
> Barry Song wrote:
>> Signed-off-by: Barry Song <21cnbao@...il.com>
>> Signed-off-by: H.J. Oertel <oe@...t.de>
>> ---
>>  -v3: use structures to describe the layout of registers
>
> Wow, that was quick, thanks for your effort and patience.
>
> Please use checkpath.pl to detect the obvious coding style problems,
> especially the "WARNING: line over 80 characters".
>
> I also think the declaration of reg should have the __iomem as well:
>
>        struct bfin_can_regs __iomem *reg = priv->membase;
>
>>  drivers/net/can/Kconfig    |    9 +
>>  drivers/net/can/Makefile   |    1 +
>>  drivers/net/can/bfin_can.c |  836 ++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 846 insertions(+), 0 deletions(-)
>>  create mode 100644 drivers/net/can/bfin_can.c
>>
>> diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
>> index bb803fa..8c485aa 100644
>> --- a/drivers/net/can/Kconfig
>> +++ b/drivers/net/can/Kconfig
>> @@ -54,6 +54,15 @@ config CAN_MCP251X
>>       ---help---
>>         Driver for the Microchip MCP251x SPI CAN controllers.
>>
>> +config CAN_BFIN
>> +     depends on CAN_DEV && (BF534 || BF536 || BF537 || BF538 || BF539 || BF54x)
>> +     tristate "Analog Devices Blackfin on-chip CAN"
>> +     ---help---
>> +       Driver for the Analog Devices Blackfin on-chip CAN controllers
>> +
>> +       To compile this driver as a module, choose M here: the
>> +       module will be called bfin_can.
>> +
>>  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 56899fe..7a702f2 100644
>> --- a/drivers/net/can/Makefile
>> +++ b/drivers/net/can/Makefile
>> @@ -14,5 +14,6 @@ obj-$(CONFIG_CAN_MSCAN)             += mscan/
>>  obj-$(CONFIG_CAN_AT91)               += at91_can.o
>>  obj-$(CONFIG_CAN_TI_HECC)    += ti_hecc.o
>>  obj-$(CONFIG_CAN_MCP251X)    += mcp251x.o
>> +obj-$(CONFIG_CAN_BFIN)               += bfin_can.o
>>
>>  ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
>> diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
>> new file mode 100644
>> index 0000000..b94169d
>> --- /dev/null
>> +++ b/drivers/net/can/bfin_can.c
>> @@ -0,0 +1,836 @@
>> +/*
>> + * Blackfin On-Chip CAN Driver
>> + *
>> + * Copyright 2004-2009 Analog Devices Inc.
>
> Consider adding your copyright here, with a name and address.
>
>> + *
>> + * Enter bugs at http://blackfin.uclinux.org/
>> + *
>> + * Licensed under the GPL-2 or later.
>
> Please add the usual "GPL-2 or later" bla-bla here.
Here I am not completely sure. But I am sure I am using the head file
template of ADI which has been used widely in kernel and should be
right.
>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/types.h>
>
> I think you don't need "types.h" as the code no longer uses "uint*_t".
>
>> +#include <linux/bitops.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/errno.h>
>> +#include <linux/netdevice.h>
>> +#include <linux/skbuff.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include <linux/can.h>
>> +#include <linux/can/dev.h>
>> +#include <linux/can/error.h>
>> +
>> +#include <asm/portmux.h>
>> +
>> +#define DRV_NAME "bfin_can"
>> +#define BFIN_CAN_TIMEOUT 100
>> +
>> +/*
>> + * transmit and receive channels
>> + */
>> +#define TRANSMIT_CHL         24
>> +#define RECEIVE_STD_CHL      0
>> +#define RECEIVE_EXT_CHL      4
>> +#define RECEIVE_RTR_CHL      8
>> +#define RECEIVE_EXT_RTR_CHL  12
>> +#define MAX_CHL_NUMBER         32
>
> The alignment of the numbers is inconsistant.
>
>> +/*
>> + * bfin can registers layout
>> + */
>> +struct bfin_can_mask_regs {
>> +     u16 aml;
>> +     u16 dummy1;
>> +     u16 amh;
>> +     u16 dummy2;
>> +};
>> +
>> +struct bfin_can_channel_regs {
>> +     u16 data[8];
>> +     u16 dlc;
>> +     u16 dummy1;
>> +     u16 tsv;
>> +     u16 dummy2;
>> +     u16 id0;
>> +     u16 dummy3;
>> +     u16 id1;
>> +     u16 dummy4;
>> +};
>> +
>> +struct bfin_can_regs {
>> +     /*
>> +      * global control and status registers
>> +      */
>> +     u16 mc1;           /* offset 0 */
>> +     u16 dummy1;
>> +     u16 md1;           /* offset 4 */
>> +     u16 rsv1[13];
>> +     u16 mbtif1;        /* offset 0x20 */
>> +     u16 dummy2;
>> +     u16 mbrif1;        /* offset 0x24 */
>> +     u16 dummy3;
>> +     u16 mbim1;         /* offset 0x28 */
>> +     u16 rsv2[11];
>
> Ditto.
>
>> +     u16 mc2;          /* offset 0x40 */
>> +     u16 dummy4;
>> +     u16 md2;          /* offset 0x44 */
>> +     u16 dummy5;
>> +     u16 trs2;         /* offset 0x48 */
>> +     u16 rsv3[11];
>> +     u16 mbtif2;       /* offset 0x60 */
>> +     u16 dummy6;
>> +     u16 mbrif2;       /* offset 0x64 */
>> +     u16 dummy7;
>> +     u16 mbim2;        /* offset 0x68 */
>> +     u16 rsv4[11];
>> +     u16 clk;          /* offset 0x80 */
>> +     u16 dummy8;
>> +     u16 timing;       /* offset 0x84 */
>> +     u16 rsv5[3];
>> +     u16 status;       /* offset 0x8c */
>> +     u16 dummy9;
>> +     u16 cec;          /* offset 0x90 */
>> +     u16 dummy10;
>> +     u16 gis;          /* offset 0x94 */
>> +     u16 dummy11;
>> +     u16 gim;          /* offset 0x98 */
>> +     u16 rsv6[3];
>> +     u16 ctrl;         /* offset 0xa0 */
>> +     u16 dummy12;
>> +     u16 intr;         /* offset 0xa4 */
>> +     u16 rsv7[7];
>> +     u16 esr;          /* offset 0xb4 */
>> +     u16 rsv8[37];
>> +
>> +     /*
>> +      * channel(mailbox) mask and message registers
>> +      */
>> +     struct bfin_can_mask_regs    msk[MAX_CHL_NUMBER]; /* offset 0x100 */
>
> Don't align "msk", please.
>
>> +     struct bfin_can_channel_regs chl[MAX_CHL_NUMBER]; /* offset 0x200 */
>> +};
>> +
>> +/*
>> + * bfin can private data
>> + */
>> +struct bfin_can_priv {
>> +     struct can_priv can;    /* must be the first member */
>> +     struct net_device *dev;
>> +     void __iomem *membase;
>> +     int rx_irq;
>> +     int tx_irq;
>> +     int err_irq;
>> +     unsigned short *pin_list;
>> +};
>> +
>> +/*
>> + * bfin can timing parameters
>> + */
>> +static struct can_bittiming_const bfin_can_bittiming_const = {
>> +     .name = DRV_NAME,
>> +     .tseg1_min = 1,
>> +     .tseg1_max = 16,
>> +     .tseg2_min = 1,
>> +     .tseg2_max = 8,
>> +     .sjw_max = 4,
>> +     /* Although the BRP field can be set to any value, it is recommended
>
> Should be:
>
>        /*
>         * Although the ...
>
>
>> +      * that the value be greater than or equal to 4, as restrictions
>> +      * apply to the bit timing configuration when BRP is less than 4.
>> +      */
>> +     .brp_min = 4,
>> +     .brp_max = 1024,
>> +     .brp_inc = 1,
>> +};
>
> Well, I'm still not a friend of the following inline functions,
> especially the *one-liners* which are called just *once*. With the usage
> of structs they seem even more useless.
>
>> +/*
>> + * inline functions to read/write ID, data length and payload of CAN frame
>> + */
>> +static inline void bfin_can_write_oid(struct bfin_can_priv *priv, int channel, canid_t id)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     writew((id << 2) + AME, &reg->chl[channel].id1);
>> +}
>> +
>> +static inline void bfin_can_write_oid_rtr(struct bfin_can_priv *priv, int channel, canid_t id)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     writew((id << 2) + AME + RTR, &reg->chl[channel].id1);
>> +}
>> +
>> +static inline canid_t bfin_can_read_oid(struct bfin_can_priv *priv, int channel)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     return (readw(&reg->chl[channel].id1) & 0x1ffc) >> 2;
>> +}
>> +
>> +static inline void bfin_can_write_xoid(struct bfin_can_priv *priv, int channel, canid_t id)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     writew(id, &reg->chl[channel].id0);
>> +     writew(((id & 0x1FFF0000) >> 16) + IDE + AME, &reg->chl[channel].id1);
>> +}
>> +
>> +static inline void bfin_can_write_xoid_rtr(struct bfin_can_priv *priv, int channel, canid_t id)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     writew(id, &reg->chl[channel].id0);
>> +     writew(((id & 0x1FFF0000) >> 16) + IDE + AME + RTR, &reg->chl[channel].id1);
>> +}
>> +
>> +static inline canid_t bfin_can_read_xoid(struct bfin_can_priv *priv, int channel)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     return ((readw(&reg->chl[channel].id1) & 0x1FFF) << 16) + readw(&reg->chl[channel].id0);
>> +}
>> +
>> +static inline void bfin_can_write_dlc(struct bfin_can_priv *priv, int channel, u8 dlc)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     writew(dlc, &reg->chl[channel].dlc);
>> +}
>
> Look, "writew(dlc, &reg->chl[channel].dlc)" makes already pretty clear
> what the call does.
>
>> +static inline u8 bfin_can_read_dlc(struct bfin_can_priv *priv, int channel)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     return readw(&reg->chl[channel].dlc);
>> +}
>
> Ditto.
>
>> +static inline void bfin_can_write_data(struct bfin_can_priv *priv, int channel, u8 *data, u8 dlc)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     int i;
>> +     u16 val;
>> +
>> +     for (i = 0; i < 8; i += 2) {
>> +             val = ((7 - i) < dlc ? (data[7 - i]) : 0) +
>> +                     ((6 - i) < dlc ? (data[6 - i] << 8) : 0);
>> +             writew(val, &reg->chl[channel].data[i]);
>> +     }
>> +}
>> +
>> +static inline void bfin_can_read_data(struct bfin_can_priv *priv, int channel, u8 *data, u8 dlc)
>> +{
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     int i;
>> +     u16 val;
>> +
>> +     for (i = 0; i < 8; i += 2) {
>> +             val = readw(&reg->chl[channel].data[i]);
>> +             data[7 - i] = (7 - i) < dlc ? val : 0;
>> +             data[6 - i] = (6 - i) < dlc ? (val >> 8) : 0;
>> +     }
>> +}
>> +
>> +static int bfin_can_set_bittiming(struct net_device *dev)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     struct can_bittiming *bt = &priv->can.bittiming;
>> +     u16 clk, timing;
>> +
>> +     clk = bt->brp - 1;
>> +     timing = ((bt->sjw - 1) << 8) | (bt->prop_seg + bt->phase_seg1 - 1) |
>> +             ((bt->phase_seg2 - 1) << 4);
>> +
>> +     /*
>> +      * If the SAM bit is set, the input signal is oversampled three times at the SCLK rate.
>> +      */
>> +     if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
>> +             timing |= SAM;
>> +
>> +     writew(clk, &reg->clk);
>> +     writew(timing, &reg->timing);
>> +
>> +     dev_info(dev->dev.parent, "setting CLOCK=0x%04x TIMING=0x%04x\n", clk, timing);
>> +     return 0;
>> +}
>> +
>> +static void bfin_can_set_reset_mode(struct net_device *dev)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     int timeout = BFIN_CAN_TIMEOUT;
>> +     int i;
>> +
>> +     /* disable interrupts */
>> +     writew(0, &reg->mbim1);
>> +     writew(0, &reg->mbim2);
>> +     writew(0, &reg->gim);
>> +
>> +     /* reset can and enter configuration mode */
>> +     writew(SRS | CCR, &reg->ctrl);
>> +     SSYNC();
>> +     writew(CCR, &reg->ctrl);
>> +     SSYNC();
>> +     while (!(readw(&reg->ctrl) & CCA)) {
>> +             udelay(10);
>> +             if (--timeout == 0) {
>> +                     dev_err(dev->dev.parent, "fail to enter configuration mode\n");
>> +                     BUG();
>> +             }
>> +     }
>
> Isn't using BUG() to harsh here? Using and handling a proper return code
> might already be sufficient.
Due to the hardware design, here timeout will never happen. If it
happens, that means hardware component has crashed.

>
>> +
>> +     /*
>> +      * All mailbox configurations are marked as inactive
>> +      * by writing to CAN Mailbox Configuration Registers 1 and 2
>> +      * For all bits: 0 - Mailbox disabled, 1 - Mailbox enabled
>> +      */
>> +     writew(0, &reg->mc1);
>> +     writew(0, &reg->mc2);
>> +
>> +     /* Set Mailbox Direction */
>> +     writew(0xFFFF, &reg->md1);   /* mailbox 1-16 are RX */
>> +     writew(0, &reg->md2);   /* mailbox 17-32 are TX */
>> +
>> +     /* RECEIVE_STD_CHL */
>> +     for (i = 0; i < 2; i++) {
>> +             writew(0, &reg->chl[RECEIVE_STD_CHL + i].id0);
>> +             writew(AME, &reg->chl[RECEIVE_STD_CHL + i].id1);
>> +             writew(0, &reg->chl[RECEIVE_STD_CHL + i].dlc);
>> +             writew(0x1FFF, &reg->msk[RECEIVE_STD_CHL + i].amh);
>> +             writew(0xFFFF, &reg->msk[RECEIVE_STD_CHL + i].aml);
>> +     }
>> +
>> +     /* RECEIVE_EXT_CHL */
>> +     for (i = 0; i < 2; i++) {
>> +             writew(0, &reg->chl[RECEIVE_EXT_CHL + i].id0);
>> +             writew(AME | IDE, &reg->chl[RECEIVE_EXT_CHL + i].id1);
>> +             writew(0, &reg->chl[RECEIVE_EXT_CHL + i].dlc);
>> +             writew(0x1FFF, &reg->msk[RECEIVE_EXT_CHL + i].amh);
>> +             writew(0xFFFF, &reg->msk[RECEIVE_EXT_CHL + i].aml);
>> +     }
>> +
>> +     writew(BIT(TRANSMIT_CHL - 16), &reg->mc2);
>> +     writew(BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL), &reg->mc1);
>> +     SSYNC();
>> +
>> +     priv->can.state = CAN_STATE_STOPPED;
>> +}
>> +
>> +static void bfin_can_set_normal_mode(struct net_device *dev)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     int timeout = BFIN_CAN_TIMEOUT;
>> +
>> +     /*
>> +      * leave configuration mode
>> +      */
>> +     writew(readw(&reg->ctrl) & ~CCR, &reg->ctrl);
>> +
>> +     while (readw(&reg->status) & CCA) {
>> +             udelay(10);
>> +             if (--timeout == 0) {
>> +                     dev_err(dev->dev.parent, "fail to leave configuration mode\n");
>> +                     BUG();
>> +             }
>> +     }
>> +
>> +     /*
>> +      * clear _All_  tx and rx interrupts
>> +      */
>> +     writew(0xFFFF, &reg->mbtif1);
>> +     writew(0xFFFF, &reg->mbtif2);
>> +     writew(0xFFFF, &reg->mbrif1);
>> +     writew(0xFFFF, &reg->mbrif2);
>> +
>> +     /*
>> +      * clear global interrupt status register
>> +      */
>> +     writew(0x7FF, &reg->gis); /* overwrites with '1' */
>> +
>> +     /*
>> +      * Initialize Interrupts
>> +      * - set bits in the mailbox interrupt mask register
>> +      * - global interrupt mask
>> +      */
>> +     writew(BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL), &reg->mbim1);
>> +     writew(BIT(TRANSMIT_CHL - 16), &reg->mbim2);
>> +
>> +     writew(EPIM | BOIM | RMLIM, &reg->gim);
>> +     SSYNC();
>> +}
>> +
>> +static void bfin_can_start(struct net_device *dev)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +
>> +     /* leave reset mode */
>> +     if (priv->can.state != CAN_STATE_STOPPED)
>> +             bfin_can_set_reset_mode(dev);
>> +
>> +     /* leave reset mode */
>> +     bfin_can_set_normal_mode(dev);
>> +}
>> +
>> +static int bfin_can_set_mode(struct net_device *dev, enum can_mode mode)
>> +{
>> +     switch (mode) {
>> +     case CAN_MODE_START:
>> +             bfin_can_start(dev);
>> +             if (netif_queue_stopped(dev))
>> +                     netif_wake_queue(dev);
>> +             break;
>> +
>> +     default:
>> +             return -EOPNOTSUPP;
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     struct can_frame *cf = (struct can_frame *)skb->data;
>> +     u8 dlc;
>> +     canid_t id;
>> +
>> +     netif_stop_queue(dev);
>> +
>> +     dlc = cf->can_dlc;
>> +     id = cf->can_id;
>> +
>> +     /* fill id and data length code */
>> +     if (id & CAN_EFF_FLAG) {
>> +             if (id & CAN_RTR_FLAG)
>> +                     bfin_can_write_xoid_rtr(priv, TRANSMIT_CHL, id);
>> +             else
>> +                     bfin_can_write_xoid(priv, TRANSMIT_CHL, id);
>> +     } else {
>> +             if (id & CAN_RTR_FLAG)
>> +                     bfin_can_write_oid_rtr(priv, TRANSMIT_CHL, id);
>> +             else
>> +                     bfin_can_write_oid(priv, TRANSMIT_CHL, id);
>> +     }
>> +
>> +     bfin_can_write_data(priv, TRANSMIT_CHL, cf->data, dlc);
>> +
>> +     bfin_can_write_dlc(priv, TRANSMIT_CHL, dlc);
>> +
>> +     dev->trans_start = jiffies;
>> +
>> +     can_put_echo_skb(skb, dev, 0);
>> +
>> +     /* set transmit request */
>> +     writew(BIT(TRANSMIT_CHL - 16), &reg->trs2);
>> +     return 0;
>> +}
>> +
>> +static void bfin_can_rx(struct net_device *dev, u16 isrc)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct net_device_stats *stats = &dev->stats;
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     struct can_frame *cf;
>> +     struct sk_buff *skb;
>> +     canid_t id;
>> +     u8 dlc;
>> +     int obj;
>> +
>> +     skb = alloc_can_skb(dev, &cf);
>> +     if (skb == NULL)
>> +             return;
>> +
>> +     /* get id and data length code */
>> +     if (isrc & BIT(RECEIVE_EXT_CHL)) {
>> +             /* extended frame format (EFF) */
>> +             id = bfin_can_read_xoid(priv, RECEIVE_EXT_CHL);
>> +             id |= CAN_EFF_FLAG;
>> +             obj = RECEIVE_EXT_CHL;
>> +     } else {
>> +             /* standard frame format (SFF) */
>> +             id = bfin_can_read_oid(priv, RECEIVE_STD_CHL);
>> +             obj = RECEIVE_STD_CHL;
>> +     }
>> +     if (readw(&reg->chl[obj].id1) & RTR)
>> +             id |= CAN_RTR_FLAG;
>> +     dlc = bfin_can_read_dlc(priv, obj);
>> +
>> +     cf->can_id = id;
>> +     cf->can_dlc = dlc;
>> +
>> +     bfin_can_read_data(priv, obj, cf->data, dlc);
>> +
>> +     netif_rx(skb);
>> +
>> +     stats->rx_packets++;
>> +     stats->rx_bytes += dlc;
>> +}
>> +
>> +static int bfin_can_err(struct net_device *dev, u16 isrc, u16 status)
>> +{
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     struct net_device_stats *stats = &dev->stats;
>> +     struct can_frame *cf;
>> +     struct sk_buff *skb;
>> +     enum can_state state = priv->can.state;
>> +
>> +     skb = alloc_can_err_skb(dev, &cf);
>> +     if (skb == NULL)
>> +             return -ENOMEM;
>> +
>> +     if (isrc & RMLIS) {
>> +             /* data overrun interrupt */
>> +             dev_dbg(dev->dev.parent, "data overrun interrupt\n");
>> +             cf->can_id |= CAN_ERR_CRTL;
>> +             cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
>> +             stats->rx_over_errors++;
>> +             stats->rx_errors++;
>> +     }
>> +
>> +     if (isrc & BOIS) {
>> +             dev_dbg(dev->dev.parent, "bus-off mode interrupt\n");
>> +
>
> Empty line?
>
>> +             state = CAN_STATE_BUS_OFF;
>> +             cf->can_id |= CAN_ERR_BUSOFF;
>> +             can_bus_off(dev);
>> +     }
>> +
>> +     if (isrc & EPIS) {
>> +             /* error passive interrupt */
>> +             dev_dbg(dev->dev.parent, "error passive interrupt\n");
>> +             state = CAN_STATE_ERROR_PASSIVE;
>> +     }
>> +
>> +     if ((isrc & EWTIS) || (isrc & EWRIS)) {
>> +             dev_dbg(dev->dev.parent, "Error Warning Transmit/Receive Interrupt\n");
>> +             state = CAN_STATE_ERROR_WARNING;
>> +     }
>> +
>> +     if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
>> +                             state == CAN_STATE_ERROR_PASSIVE)) {
>> +             u16 cec = readw(&reg->cec);
>> +             u8 rxerr = cec;
>> +             u8 txerr = cec >> 8;
>
> Add an empty line here, please.
>
>> +             cf->can_id |= CAN_ERR_CRTL;
>> +             if (state == CAN_STATE_ERROR_WARNING) {
>> +                     priv->can.can_stats.error_warning++;
>> +                     cf->data[1] = (txerr > rxerr) ?
>> +                             CAN_ERR_CRTL_TX_WARNING :
>> +                             CAN_ERR_CRTL_RX_WARNING;
>> +             } else {
>> +                     priv->can.can_stats.error_passive++;
>> +                     cf->data[1] = (txerr > rxerr) ?
>> +                             CAN_ERR_CRTL_TX_PASSIVE :
>> +                             CAN_ERR_CRTL_RX_PASSIVE;
>> +             }
>> +     }
>> +
>> +     if (status) {
>> +             priv->can.can_stats.bus_error++;
>> +
>> +             cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
>> +
>> +             if (status & BEF)
>> +                     cf->data[2] |= CAN_ERR_PROT_BIT;
>> +             else if (status & FER)
>> +                     cf->data[2] |= CAN_ERR_PROT_FORM;
>> +             else if (status & SER)
>> +                     cf->data[2] |= CAN_ERR_PROT_STUFF;
>> +             else
>> +                     cf->data[2] |= CAN_ERR_PROT_UNSPEC;
>> +     }
>
> Add {} here as well.
{} will cause checkpatch warning if it is given to only one line.

>
>> +     priv->can.state = state;
>> +
>> +     netif_rx(skb);
>> +
>> +     stats->rx_packets++;
>> +     stats->rx_bytes += cf->can_dlc;
>> +
>> +     return 0;
>> +}
>> +
>> +irqreturn_t bfin_can_interrupt(int irq, void *dev_id)
>> +{
>> +     struct net_device *dev = dev_id;
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     struct net_device_stats *stats = &dev->stats;
>> +     u16 status, isrc;
>> +
>> +     if ((irq == priv->tx_irq) && readw(&reg->mbtif2)) {
>> +             /* transmission complete interrupt */
>> +             writew(0xFFFF, &reg->mbtif2);
>> +             stats->tx_packets++;
>> +             stats->tx_bytes += bfin_can_read_dlc(priv, TRANSMIT_CHL);
>> +             can_get_echo_skb(dev, 0);
>> +             netif_wake_queue(dev);
>> +     } else if ((irq == priv->rx_irq) && readw(&reg->mbrif1)) {
>> +             /* receive interrupt */
>> +             isrc = readw(&reg->mbrif1);
>> +             writew(0xFFFF, &reg->mbrif1);
>> +             bfin_can_rx(dev, isrc);
>> +     } else if ((irq == priv->err_irq) && readw(&reg->gis)) {
>> +             /* error interrupt */
>> +             isrc = readw(&reg->gis);
>> +             status = readw(&reg->esr);
>> +             writew(0x7FF, &reg->gis);
>> +             bfin_can_err(dev, isrc, status);
>> +     } else
>> +             return IRQ_NONE;
>
> Use {} here as well.
{} will cause checkpatch warning if it is given to only one line.
>
>> +
>> +     return IRQ_HANDLED;
>> +}
>> +
>> +static int bfin_can_open(struct net_device *dev)
>> +{
>> +     int err;
>> +
>> +     /* set chip into reset mode */
>> +     bfin_can_set_reset_mode(dev);
>> +
>> +     /* common open */
>> +     err = open_candev(dev);
>> +     if (err)
>> +             return err;
>> +
>> +     /* init and start chi */
>> +     bfin_can_start(dev);
>> +
>> +     netif_start_queue(dev);
>> +
>> +     return 0;
>> +}
>> +
>> +static int bfin_can_close(struct net_device *dev)
>> +{
>> +     netif_stop_queue(dev);
>> +     bfin_can_set_reset_mode(dev);
>> +
>> +     close_candev(dev);
>> +
>> +     return 0;
>> +}
>> +
>> +struct net_device *alloc_bfin_candev(void)
>> +{
>> +     struct net_device *dev;
>> +     struct bfin_can_priv *priv;
>> +
>> +     dev = alloc_candev(sizeof(*priv));
>> +     if (!dev)
>> +             return NULL;
>> +
>> +     priv = netdev_priv(dev);
>> +
>> +     priv->dev = dev;
>> +     priv->can.bittiming_const = &bfin_can_bittiming_const;
>> +     priv->can.do_set_bittiming = bfin_can_set_bittiming;
>> +     priv->can.do_set_mode = bfin_can_set_mode;
>> +
>> +     return dev;
>> +}
>> +
>> +static const struct net_device_ops bfin_can_netdev_ops = {
>> +     .ndo_open               = bfin_can_open,
>> +     .ndo_stop               = bfin_can_close,
>> +     .ndo_start_xmit         = bfin_can_start_xmit,
>> +};
>> +
>> +static int __devinit bfin_can_probe(struct platform_device *pdev)
>> +{
>> +     int err;
>> +     struct net_device *dev;
>> +     struct bfin_can_priv *priv;
>> +     struct resource *res_mem, *rx_irq, *tx_irq, *err_irq;
>> +     unsigned short *pdata;
>> +
>> +     pdata = pdev->dev.platform_data;
>> +     if (!pdata) {
>> +             dev_err(&pdev->dev, "No platform data provided!\n");
>> +             err = -EINVAL;
>> +             goto exit;
>> +     }
>> +
>> +     res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +     rx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>> +     tx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
>> +     err_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
>> +     if (!res_mem || !rx_irq || !tx_irq || !err_irq) {
>> +             err = -EINVAL;
>> +             goto exit;
>> +     }
>> +
>> +     if (!request_mem_region(res_mem->start, resource_size(res_mem),
>> +                             dev_name(&pdev->dev))) {
>> +             err = -EBUSY;
>> +             goto exit;
>> +     }
>> +
>> +     /* request peripheral pins */
>> +     err = peripheral_request_list(pdata, dev_name(&pdev->dev));
>> +     if (err)
>> +             goto exit_mem_release;
>> +
>> +     dev = alloc_bfin_candev();
>> +     if (!dev) {
>> +             err = -ENOMEM;
>> +             goto exit_peri_pin_free;
>> +     }
>> +
>> +     /* register interrupt handler */
>> +     err = request_irq(rx_irq->start, &bfin_can_interrupt, 0,
>> +                     "bfin-can-rx", (void *)dev);
>> +     if (err)
>> +             goto exit_candev_free;
>> +     err = request_irq(tx_irq->start, &bfin_can_interrupt, 0,
>> +                     "bfin-can-tx", (void *)dev);
>> +     if (err)
>> +             goto exit_rx_irq_free;
>> +     err = request_irq(err_irq->start, &bfin_can_interrupt, 0,
>> +                     "bfin-can-err", (void *)dev);
>> +     if (err)
>> +             goto exit_tx_irq_free;
>
> If possible, please request/free IRQs in the open and stop functions.
>
>> +     priv = netdev_priv(dev);
>> +     priv->membase = (void __iomem *)res_mem->start;
>> +     priv->rx_irq = rx_irq->start;
>> +     priv->tx_irq = tx_irq->start;
>> +     priv->err_irq = err_irq->start;
>> +     priv->pin_list = pdata;
>> +     priv->can.clock.freq = get_sclk();
>> +
>> +     dev_set_drvdata(&pdev->dev, dev);
>> +     SET_NETDEV_DEV(dev, &pdev->dev);
>> +
>> +     dev->flags |= IFF_ECHO; /* we support local echo */
>> +     dev->netdev_ops = &bfin_can_netdev_ops;
>> +
>> +     bfin_can_set_reset_mode(dev);
>> +
>> +     err = register_candev(dev);
>> +     if (err) {
>> +             dev_err(&pdev->dev, "registering failed (err=%d)\n", err);
>> +             goto exit_err_irq_free;
>> +     }
>> +
>> +     dev_info(&pdev->dev, "%s device registered (reg_base=%p, rx_irq=%d, tx_irq=%d, err_irq=%d, sclk=%d)\n",
>> +                     DRV_NAME, (void *)priv->membase, priv->rx_irq, priv->tx_irq, priv->err_irq,
>> +                     priv->can.clock.freq);
>> +     return 0;
>> +
>> +exit_err_irq_free:
>> +     free_irq(err_irq->start, dev);
>> +exit_tx_irq_free:
>> +     free_irq(tx_irq->start, dev);
>> +exit_rx_irq_free:
>> +     free_irq(rx_irq->start, dev);
>> +exit_candev_free:
>> +     free_candev(dev);
>> +exit_peri_pin_free:
>> +     peripheral_free_list(pdata);
>> +exit_mem_release:
>> +     release_mem_region(res_mem->start, resource_size(res_mem));
>> +exit:
>> +     return err;
>> +}
>> +
>> +static int __devexit bfin_can_remove(struct platform_device *pdev)
>> +{
>> +     struct net_device *dev = dev_get_drvdata(&pdev->dev);
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct resource *res;
>> +
>> +     bfin_can_set_reset_mode(dev);
>> +
>> +     unregister_candev(dev);
>> +
>> +     dev_set_drvdata(&pdev->dev, NULL);
>> +
>> +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +     release_mem_region(res->start, resource_size(res));
>> +
>> +     free_irq(priv->rx_irq, dev);
>> +     free_irq(priv->tx_irq, dev);
>> +     free_irq(priv->err_irq, dev);
>> +     peripheral_free_list(priv->pin_list);
>> +
>> +     free_candev(dev);
>> +     return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +static int bfin_can_suspend(struct platform_device *pdev, pm_message_t mesg)
>> +{
>> +     struct net_device *dev = dev_get_drvdata(&pdev->dev);
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +     int timeout = BFIN_CAN_TIMEOUT;
>> +
>> +     if (netif_running(dev)) {
>> +             /* enter sleep mode */
>> +             writew(readw(&reg->ctrl) | SMR, &reg->ctrl);
>> +             SSYNC();
>> +             while (!(readw(&reg->intr) & SMACK)) {
>> +                     udelay(10);
>> +                     if (--timeout == 0) {
>> +                             dev_err(dev->dev.parent, "fail to enter sleep mode\n");
>> +                             BUG();
>> +                     }
>> +             }
>
> It's already the third time that this timeout check is used. A common
> function would make sense.
Every time, the check condition is different and print information
will change. It is ugly to define only one function.
>
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static int bfin_can_resume(struct platform_device *pdev)
>> +{
>> +     struct net_device *dev = dev_get_drvdata(&pdev->dev);
>> +     struct bfin_can_priv *priv = netdev_priv(dev);
>> +     struct bfin_can_regs *reg = priv->membase;
>> +
>> +     if (netif_running(dev)) {
>> +             /* leave sleep mode */
>> +             writew(0, &reg->intr);
>> +             SSYNC();
>> +     }
>> +
>> +     return 0;
>> +}
>> +#else
>> +#define bfin_can_suspend NULL
>> +#define bfin_can_resume NULL
>> +#endif       /* CONFIG_PM */
>> +
>> +static struct platform_driver bfin_can_driver = {
>> +     .probe = bfin_can_probe,
>> +     .remove = __devexit_p(bfin_can_remove),
>> +     .suspend = bfin_can_suspend,
>> +     .resume = bfin_can_resume,
>> +     .driver = {
>> +             .name = DRV_NAME,
>> +             .owner = THIS_MODULE,
>> +     },
>> +};
>> +
>> +static int __init bfin_can_init(void)
>> +{
>> +     return platform_driver_register(&bfin_can_driver);
>> +}
>> +
>
> Remove empty line above, please.
>
>> +module_init(bfin_can_init);
>> +
>> +static void __exit bfin_can_exit(void)
>> +{
>> +     platform_driver_unregister(&bfin_can_driver);
>> +}
>> +
>
> Ditto.
>
>> +module_exit(bfin_can_exit);
>> +
>> +MODULE_AUTHOR("Barry Song <21cnbao@...il.com>");
>> +MODULE_LICENSE("GPL");
>> +MODULE_DESCRIPTION("Blackfin on-chip CAN netdevice driver");
>
> Wolfgang.
>
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