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Date: Mon, 20 Dec 2010 12:29:53 +0800
From: Bhupesh SHARMA <bhupesh.sharma@...com>
To: Wolfgang Grandegger <wg@...ndegger.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"Socketcan-core@...ts.berlios.de" <Socketcan-core@...ts.berlios.de>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: RE: [PATCH net-next-2.6 v2 1/1] can: c_can: Added support for Bosch
C_CAN controller
Hi Wolfgang,
Thanks for the review.
Please see my replies in-line:
> here comes my first quick preview.
> On 12/15/2010 10:58 AM, Bhupesh Sharma wrote:
> > Bosch C_CAN controller is a full-CAN implementation which is
> compliant
> > to CAN protocol version 2.0 part A and B. Bosch C_CAN user manual can
> be
> > obtained from:
> > http://www.semiconductors.bosch.de/pdf/Users_Manual_C_CAN.pdf
> >
> > This patch adds the support for this controller.
> > The following are the design choices made while writing the
> controller driver:
> > 1. Interface Register set IF1 has be used only in the current design.
> > 2. Out of the 32 Message objects available, 16 are kept aside for RX
> purposes
> > and the rest for TX purposes.
> > 3. NAPI implementation is such that both the TX and RX paths function
> in
> > polling mode.
> >
> > Changes since V1:
> > 1. Implemented C_CAN as a platform driver with means of providing the
> > platform details and register offsets which may vary for different
> SoCs
> > through platform data struct.
> > 2. Implemented NAPI.
> > 3. Removed memcpy calls globally.
> > 4. Implemented CAN_CTRLMODE_*
> > 5. Implemented and used priv->can.do_get_berr_counter.
> > 6. Implemented c_can registers as a struct instead of enum.
> > 7. Improved the TX path by implementing routines to get next Tx and
> echo msg
> > objects.
> >
> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...com>
> > ---
> > drivers/net/can/Kconfig | 7 +
> > drivers/net/can/Makefile | 1 +
> > drivers/net/can/c_can.c | 1217
> ++++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 1225 insertions(+), 0 deletions(-)
> > create mode 100644 drivers/net/can/c_can.c
> >
> > diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
> > index 9d9e453..25d9d2e 100644
> > --- a/drivers/net/can/Kconfig
> > +++ b/drivers/net/can/Kconfig
> > @@ -41,6 +41,13 @@ config CAN_AT91
> > ---help---
> > This is a driver for the SoC CAN controller in Atmel's
> AT91SAM9263.
> >
> > +config CAN_C_CAN
> > + tristate "Bosch C_CAN controller"
> > + depends on CAN_DEV
> > + ---help---
> > + If you say yes to this option, support will be included for the
> > + Bosch C_CAN controller.
> > +
> > config CAN_TI_HECC
> > depends on CAN_DEV && ARCH_OMAP3
> > tristate "TI High End CAN Controller"
> > diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
> > index 0057537..b6cbe74 100644
> > --- a/drivers/net/can/Makefile
> > +++ b/drivers/net/can/Makefile
> > @@ -12,6 +12,7 @@ obj-y += usb/
> > obj-$(CONFIG_CAN_SJA1000) += sja1000/
> > obj-$(CONFIG_CAN_MSCAN) += mscan/
> > obj-$(CONFIG_CAN_AT91) += at91_can.o
> > +obj-$(CONFIG_CAN_C_CAN) += c_can.o
> > obj-$(CONFIG_CAN_TI_HECC) += ti_hecc.o
> > obj-$(CONFIG_CAN_MCP251X) += mcp251x.o
> > obj-$(CONFIG_CAN_BFIN) += bfin_can.o
> > diff --git a/drivers/net/can/c_can.c b/drivers/net/can/c_can.c
> > new file mode 100644
> > index 0000000..c281c17
> > --- /dev/null
> > +++ b/drivers/net/can/c_can.c
> > @@ -0,0 +1,1217 @@
> > +/*
> > + * CAN bus driver for Bosch C_CAN controller
> > + *
> > + * Copyright (C) 2010 ST Microelectronics
> > + * Bhupesh Sharma <bhupesh.sharma@...com>
> > + *
> > + * Borrowed heavily from the C_CAN driver originally written by:
> > + * Copyright (C) 2007
> > + * - Sascha Hauer, Marc Kleine-Budde, Pengutronix
> <s.hauer@...gutronix.de>
> > + * - Simon Kallweit, intefo AG <simon.kallweit@...efo.ch>
> > + *
> > + * Bosch C_CAN controller is compliant to CAN protocol version 2.0
> part A and B.
> > + * Bosch C_CAN user manual can be obtained from:
> > + * http://www.semiconductors.bosch.de/pdf/Users_Manual_C_CAN.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/kernel.h>
> > +#include <linux/version.h>
> > +#include <linux/module.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/delay.h>
> > +#include <linux/netdevice.h>
> > +#include <linux/if_arp.h>
> > +#include <linux/if_ether.h>
> > +#include <linux/list.h>
> > +#include <linux/delay.h>
> > +#include <linux/workqueue.h>
> > +#include <linux/io.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/clk.h>
> > +
> > +#include <linux/can.h>
> > +#include <linux/can/dev.h>
> > +#include <linux/can/error.h>
> > +
> > +#define DRV_NAME "c_can"
> > +
> > +/* control register */
> > +#define CONTROL_TEST (1 << 7)
> > +#define CONTROL_CCE (1 << 6)
> > +#define CONTROL_DISABLE_AR (1 << 5)
> > +#define CONTROL_ENABLE_AR (0 << 5)
> > +#define CONTROL_EIE (1 << 3)
> > +#define CONTROL_SIE (1 << 2)
> > +#define CONTROL_IE (1 << 1)
> > +#define CONTROL_INIT (1 << 0)
> > +
> > +/* test register */
> > +#define TEST_RX (1 << 7)
> > +#define TEST_TX1 (1 << 6)
> > +#define TEST_TX2 (1 << 5)
> > +#define TEST_LBACK (1 << 4)
> > +#define TEST_SILENT (1 << 3)
> > +#define TEST_BASIC (1 << 2)
> > +
> > +/* status register */
> > +#define STATUS_BOFF (1 << 7)
> > +#define STATUS_EWARN (1 << 6)
> > +#define STATUS_EPASS (1 << 5)
> > +#define STATUS_RXOK (1 << 4)
> > +#define STATUS_TXOK (1 << 3)
> > +#define STATUS_LEC_MASK 0x07
> > +#define LEC_STUFF_ERROR 1
> > +#define LEC_FORM_ERROR 2
> > +#define LEC_ACK_ERROR 3
> > +#define LEC_BIT1_ERROR 4
> > +#define LEC_BIT0_ERROR 5
> > +#define LEC_CRC_ERROR 6
>
> Could be an enum!?
Yes LEC error types can be defined as enum, but #define also
seems fine.
> > +/* error counter register */
> > +#define ERR_COUNTER_TEC_MASK 0xff
> > +#define ERR_COUNTER_TEC_SHIFT 0x0
> > +#define ERR_COUNTER_REC_SHIFT 8
> > +#define ERR_COUNTER_REC_MASK (0x7f << ERR_COUNTER_REC_SHIFT)
> > +#define ERR_COUNTER_RP_SHIFT 15
> > +#define ERR_COUNTER_RP_MASK (0x1 << ERR_COUNTER_RP_SHIFT)
> > +
> > +/* bit-timing register */
> > +#define BTR_BRP_MASK 0x3f
> > +#define BTR_BRP_SHIFT 0
> > +#define BTR_SJW_SHIFT 6
> > +#define BTR_SJW_MASK (0x3 << BTR_SJW_SHIFT)
> > +#define BTR_TSEG1_SHIFT 8
> > +#define BTR_TSEG1_MASK (0xf << BTR_TSEG1_SHIFT)
> > +#define BTR_TSEG2_SHIFT 12
> > +#define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT)
> > +
> > +/* brp extension register */
> > +#define BRP_EXT_BRPE_MASK 0x0f
> > +#define BRP_EXT_BRPE_SHIFT 0
> > +
> > +/* IFx command request */
> > +#define IF_COMR_BUSY (1 << 15)
> > +
> > +/* IFx command mask */
> > +#define IF_COMM_WR (1 << 7)
> > +#define IF_COMM_MASK (1 << 6)
> > +#define IF_COMM_ARB (1 << 5)
> > +#define IF_COMM_CONTROL (1 << 4)
> > +#define IF_COMM_CLR_INT_PND (1 << 3)
> > +#define IF_COMM_TXRQST (1 << 2)
> > +#define IF_COMM_DATAA (1 << 1)
> > +#define IF_COMM_DATAB (1 << 0)
> > +#define IF_COMM_ALL (IF_COMM_MASK | IF_COMM_ARB | \
> > + IF_COMM_CONTROL | IF_COMM_TXRQST | \
> > + IF_COMM_DATAA | IF_COMM_DATAB)
> > +
> > +/* IFx arbitration */
> > +#define IF_ARB_MSGVAL (1 << 15)
> > +#define IF_ARB_MSGXTD (1 << 14)
> > +#define IF_ARB_TRANSMIT (1 << 13)
> > +
> > +/* IFx message control */
> > +#define IF_MCONT_NEWDAT (1 << 15)
> > +#define IF_MCONT_MSGLST (1 << 14)
> > +#define IF_MCONT_INTPND (1 << 13)
> > +#define IF_MCONT_UMASK (1 << 12)
> > +#define IF_MCONT_TXIE (1 << 11)
> > +#define IF_MCONT_RXIE (1 << 10)
> > +#define IF_MCONT_RMTEN (1 << 9)
> > +#define IF_MCONT_TXRQST (1 << 8)
> > +#define IF_MCONT_EOB (1 << 7)
> > +
> > +/*
> > + * IFx register masks:
> > + * allow easy operation on 16-bit registers when the
> > + * argument is 32-bit instead
> > + */
> > +#define IFX_WRITE_LOW_16BIT(x) (x & 0xFFFF)
> > +#define IFX_WRITE_HIGH_16BIT(x) ((x & 0xFFFF0000) >> 16)
> > +
> > +/* message object split */
> > +#define C_CAN_NO_OF_OBJECTS 31
> > +#define C_CAN_MSG_OBJ_RX_NUM 16
> > +#define C_CAN_MSG_OBJ_TX_NUM 16
> > +
> > +#define C_CAN_MSG_OBJ_RX_FIRST 0
> > +#define C_CAN_MSG_OBJ_RX_LAST (C_CAN_MSG_OBJ_RX_FIRST + \
> > + C_CAN_MSG_OBJ_RX_NUM - 1)
> > +
> > +#define C_CAN_MSG_OBJ_TX_FIRST (C_CAN_MSG_OBJ_RX_LAST + 1)
> > +#define C_CAN_MSG_OBJ_TX_LAST (C_CAN_MSG_OBJ_TX_FIRST + \
> > + C_CAN_MSG_OBJ_TX_NUM - 1)
> > +#define C_CAN_NEXT_MSG_OBJ_MASK (C_CAN_MSG_OBJ_TX_NUM - 1)
> > +#define RECEIVE_OBJECT_BITS 0x0000ffff
> > +
> > +/* status interrupt */
> > +#define STATUS_INTERRUPT 0x8000
> > +
> > +/* napi related */
> > +#define C_CAN_NAPI_WEIGHT C_CAN_MSG_OBJ_RX_NUM
> > +
> > +/* c_can IF registers */
> > +struct c_can_if_regs {
> > + u16 com_reg;
> > + u16 com_mask;
> > + u16 mask1;
> > + u16 mask2;
> > + u16 arb1;
> > + u16 arb2;
> > + u16 msg_cntrl;
> > + u16 data_a1;
> > + u16 data_a2;
> > + u16 data_b1;
> > + u16 data_b2;
> > + u16 _reserved[13];
> > +};
> > +
> > +/* c_can hardware registers */
> > +struct c_can_regs {
> > + u16 control;
> > + u16 status;
> > + u16 error_counter;
> > + u16 btr;
> > + u16 ir;
> > + u16 test;
> > + u16 brp_ext;
> > + u16 _reserved1;
> > + struct c_can_if_regs ifreg[2]; /* [0] = IF1 and [1] = IF2 */
> > + u16 _reserved2[8];
> > + u16 txrqst1;
> > + u16 txrqst2;
> > + u16 _reserved3[6];
> > + u16 newdat1;
> > + u16 newdat2;
> > + u16 _reserved4[6];
> > + u16 intpnd1;
> > + u16 intpnd2;
> > + u16 _reserved5[6];
> > + u16 msgval1;
> > + u16 msgval2;
> > + u16 _reserved6[6];
> > +};
> > +
> > +/*
> > + * c_can error types:
> > + * Bus errors (BUS_OFF, ERROR_WARNING, ERROR_PASSIVE) are supported
> > + */
> > +enum c_can_bus_error_types {
> > + C_CAN_NO_ERROR = 0,
> > + C_CAN_BUS_OFF,
> > + C_CAN_ERROR_WARNING,
> > + C_CAN_ERROR_PASSIVE
> > +};
>
> > +enum c_can_interrupt_mode {
> > + ENABLE_MODULE_INTERRUPT = 0,
> > + DISABLE_MODULE_INTERRUPT,
> > + ENABLE_ALL_INTERRUPTS,
> > + DISABLE_ALL_INTERRUPTS
> > +};
> > +
> > +/* c_can private data structure */
> > +struct c_can_priv {
> > + struct can_priv can; /* must be the first member */
> > + struct napi_struct napi;
> > + struct net_device *dev;
> > + int tx_object;
> > + int current_status;
> > + int last_status;
> > + u16 (*read_reg) (struct c_can_priv *priv, void *reg);
> > + void (*write_reg) (struct c_can_priv *priv, void *reg, u16 val);
> > + struct c_can_regs __iomem *reg_base;
> > + unsigned long irq_flags; /* for request_irq() */
> > + unsigned int tx_next;
> > + unsigned int tx_echo;
> > + struct clk *clk;
> > +};
> > +
> > +static struct can_bittiming_const c_can_bittiming_const = {
> > + .name = DRV_NAME,
> > + .tseg1_min = 2, /* Time segment 1 = prop_seg + phase_seg1
> */
> > + .tseg1_max = 16,
> > + .tseg2_min = 1, /* Time segment 2 = phase_seg2 */
> > + .tseg2_max = 8,
> > + .sjw_max = 4,
> > + .brp_min = 1,
> > + .brp_max = 1024, /* 6-bit BRP field + 4-bit BRPE field*/
> > + .brp_inc = 1,
> > +};
> > +
> > +static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
> > +{
> > + return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +
> > + C_CAN_MSG_OBJ_TX_FIRST;
> > +}
> > +
> > +static inline int get_tx_echo_msg_obj(const struct c_can_priv *priv)
> > +{
> > + return (priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) +
> > + C_CAN_MSG_OBJ_TX_FIRST;
> > +}
> > +
> > +/* 16-bit c_can registers can be arranged differently in the memory
> > + * architecture of different implementations. For example: 16-bit
> > + * registers can be aligned to a 16-bit boundary or 32-bit boundary
> etc.
> > + * Handle the same by providing a common read/write interface.
> > + */
>
> Nitpicking: please use here and in other places the recommended style
> for multi-line comments:
>
> /*
> * Comment ...
> */
>
Oops. Will be done in V3
> > +static u16 c_can_read_reg_aligned_to_16bit(void *reg)
> > +{
> > + return readw(reg);
> > +}
> > +
> > +static void c_can_write_reg_aligned_to_16bit(void *reg, u16 val)
> > +{
> > + writew(val, reg);
> > +}
>
> To profit from type checking, you should use "u16 __iomem *reg" instead
> of "void *reg". Also, I think iowrite16 is preferred nowadays.
>
> > +static u16 c_can_read_reg_aligned_to_32bit(struct c_can_priv *priv,
> void *reg)
> > +{
> > + return readw(reg + (u32)reg - (u32)priv->reg_base);
> > +}
> > +
> > +static void c_can_write_reg_aligned_to_32bit(struct c_can_priv
> *priv,
> > + void *reg, u16 val)
> > +{
> > + writew(val, reg + (u32)reg - (u32)priv->reg_base);
> > +}
> > +
>
> This will not work properly on 64-bit systems. "(long)" should be used,
> at least. Any better ideas?
Hmm. I agree. Will incorporate this in V3.
> > +static u32 c_can_read_reg32(struct c_can_priv *priv, void *reg)
> > +{
> > + u32 val = priv->read_reg(priv, reg);
> > + val |= ((u32) priv->read_reg(priv, reg + 2)) << 16;
> > + return val;
> > +}
> > +
> > +static inline int c_can_configure_interrupts(struct c_can_priv
> *priv,
> > + enum c_can_interrupt_mode intr_mode)
> > +{
> > + unsigned int cntrl_save = priv->read_reg(priv,
> > + &priv->reg_base->control);
> > +
> > + switch (intr_mode) {
> > + case ENABLE_MODULE_INTERRUPT:
> > + cntrl_save |= CONTROL_IE;
> > + break;
> > + case DISABLE_MODULE_INTERRUPT:
> > + cntrl_save &= ~CONTROL_IE;
> > + break;
> > + case ENABLE_ALL_INTERRUPTS:
> > + cntrl_save |= (CONTROL_SIE | CONTROL_EIE | CONTROL_IE);
> > + break;
> > + case DISABLE_ALL_INTERRUPTS:
> > + cntrl_save &= ~(CONTROL_EIE | CONTROL_IE | CONTROL_SIE);
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + priv->write_reg(priv, &priv->reg_base->control, cntrl_save);
> > +
> > + return 0;
> > +}
>
> Do you really need this function using a switch case. The first two
> cases are not used anywhere. I think
>
> void c_can_enable_all_interrupts(struct c_can_priv *priv, int
> enable);
>
> would be fine.
Right. V3 will reflect your suggestions.
> > +static inline int c_can_object_get(struct net_device *dev,
> > + int iface, int objno, int mask)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + int timeout = (6 / priv->can.clock.freq);
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].com_mask,
> > + IFX_WRITE_LOW_16BIT(mask));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].com_reg,
> > + IFX_WRITE_LOW_16BIT(objno + 1));
> > +
> > + /* as per specs, after writting the message object number in the
> > + * IF command request register the transfer b/w interface
> > + * register and message RAM must be complete in 6 CAN-CLK
> > + * period. The delay accounts for the same
> > + */
> > + udelay(timeout);
> > + if ((priv->read_reg(priv, &priv->reg_base->ifreg[iface].com_reg))
> &
>
> I don't think you need the inner brackets.
Ok.
> > + IF_COMR_BUSY) {
> > + dev_info(dev->dev.parent, "timed out in object get\n");
> > + return -ETIMEDOUT;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static inline int c_can_object_put(struct net_device *dev,
> > + int iface, int objno, int mask)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + int timeout = (6 / priv->can.clock.freq);
>
> Hm, "timeout = 0" does not look resonable.
Let me see if I get your point here.
You mean use something like:
count = 6 /* non-zero count at start */
/* write message object no in IF COMM_REQ reg */
while (count) {
udelay(timeout);
count--;
}
/* read BUSY status from IF COM reg */
if (busy)
return -ETIMEDOUT;
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].com_mask,
> > + (IF_COMM_WR | IFX_WRITE_LOW_16BIT(mask)));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].com_reg,
> > + IFX_WRITE_LOW_16BIT(objno + 1));
> > +
> > + /* as per specs, after writting the message object number in the
> > + * IF command request register the transfer b/w interface
> > + * register and message RAM must be complete in 6 CAN-CLK
> > + * period. The delay accounts for the same
> > + */
> > + udelay(timeout);
> > + if ((priv->read_reg(priv, &priv->reg_base->ifreg[iface].com_reg))
> &
> > + IF_COMR_BUSY) {
> > + dev_info(dev->dev.parent, "timed out in object put\n");
>
> dev_err() seems more appropriate.
Ok.
> > + return -ETIMEDOUT;
> > + }
>
> Is the timeout really needed? If yes, re-trying various times would
> more
> more safe.
Yes timeout is needed as per specs. Please see the approach given above.
If you agree the same can be added in V3.
> > + return 0;
> > +}
> > +
> > +int c_can_write_msg_object(struct net_device *dev,
> > + int iface, struct can_frame *frame, int objno)
> > +{
> > + u16 flags = 0;
> > + unsigned int id;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + if (frame->can_id & CAN_EFF_FLAG) {
> > + id = frame->can_id & CAN_EFF_MASK;
> > + flags |= IF_ARB_MSGXTD;
> > + } else
> > + id = ((frame->can_id & CAN_SFF_MASK) << 18);
> > +
> > + if (!(frame->can_id & CAN_RTR_FLAG))
> > + flags |= IF_ARB_TRANSMIT;
> > +
> > + flags |= IF_ARB_MSGVAL;
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb1,
> > + IFX_WRITE_LOW_16BIT(id));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb2, flags |
> > + IFX_WRITE_HIGH_16BIT(id));
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].data_a1,
> > + (*(u16 *)(frame->data)));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].data_a2,
> > + (*(u32 *)(frame->data)) >> 16);
> > +
> > + if (frame->can_dlc > 4) {
> > + priv->write_reg(priv, &priv->reg_base-
> >ifreg[iface].data_b1,
> > + (*(u16 *)(frame->data + 4)));
> > + priv->write_reg(priv, &priv->reg_base-
> >ifreg[iface].data_b2,
> > + (*(u32 *)(frame->data + 4)) >> 16);
> > + } else
> > + *(u32 *)(frame->data + 4) = 0;
>
> Is this code endianess safe?
Marc's suggestion to use data is an array (similar to
pch driver) seems better. Do you agree to the same?
> > +
> > + return frame->can_dlc;
> > +}
> > +
> > +static int c_can_read_msg_object(struct net_device *dev, int iface,
> int objno)
> > +{
> > + u16 flags;
> > + int ctrl;
> > + unsigned int val, data;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + struct net_device_stats *stats = &dev->stats;
> > + struct sk_buff *skb;
> > + struct can_frame *frame;
> > +
> > + skb = alloc_can_skb(dev, &frame);
> > + if (!skb) {
> > + stats->rx_dropped++;
> > + return -ENOMEM;
> > + }
> > +
> > + val = c_can_object_get(dev, iface, objno, IF_COMM_ALL &
> > + ~IF_COMM_TXRQST);
> > + if (val < 0)
> > + return val;
> > +
> > + ctrl = priv->read_reg(priv, &priv->reg_base-
> >ifreg[iface].msg_cntrl);
> > + if (ctrl & IF_MCONT_MSGLST) {
> > + stats->rx_errors++;
> > + dev_info(dev->dev.parent, "msg lost in buffer %d\n",
> objno);
> > + }
>
> You should create an error message for that error as well.
Ok.
> > + frame->can_dlc = get_can_dlc(ctrl & 0x0F);
> > + data = priv->read_reg(priv, &priv->reg_base-
> >ifreg[iface].data_a1) |
> > + (priv->read_reg(priv, &priv->reg_base-
> >ifreg[iface].data_a2) <<
> > + 16);
> > + *(u32 *)(frame->data) = data;
> > + if (frame->can_dlc > 4) {
> > + data = priv->read_reg(priv,
> > + &priv->reg_base->ifreg[iface].data_b1) |
> > + (priv->read_reg(priv,
> > + &priv->reg_base->ifreg[iface].data_b2) <<
> > + 16);
> > + *(u32 *)(frame->data + 4) = data;
> > + } else
> > + *(u32 *)(frame->data + 4) = 0;
>
> Ditto.
Please see approach mentioned above.
> > + flags = priv->read_reg(priv, &priv->reg_base-
> >ifreg[iface].arb2);
> > + val = priv->read_reg(priv, &priv->reg_base->ifreg[iface].arb1) |
> > + (flags << 16);
> > +
> > + if (flags & IF_ARB_MSGXTD)
> > + frame->can_id = (val & CAN_EFF_MASK) | CAN_EFF_FLAG;
> > + else
> > + frame->can_id = (val >> 18) & CAN_SFF_MASK;
> > +
> > + if (flags & IF_ARB_TRANSMIT)
> > + frame->can_id |= CAN_RTR_FLAG;
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].msg_cntrl,
> ctrl &
> > + ~(IF_MCONT_MSGLST | IF_MCONT_INTPND |
> IF_MCONT_NEWDAT));
> > +
> > + val = c_can_object_put(dev, iface, objno, IF_COMM_CONTROL);
> > + if (val < 0)
> > + return val;
> > +
> > + netif_receive_skb(skb);
> > +
> > + stats->rx_packets++;
> > + stats->rx_bytes += frame->can_dlc;
> > +
> > + return 0;
>
> The return values are not handled anywhere!
Hmm. This is the tricky part. To be honest, a
lot of driver's don't handle all the return values.
This function is called from an isr / poll-event.
Do you think it's useful to handle the return values
there?
> > +}
> > +
> > +static int c_can_setup_receive_object(struct net_device *dev, int
> iface,
> > + int objno, unsigned int mask,
> > + unsigned int id, unsigned int mcont)
> > +{
> > + int ret;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].mask1,
> > + IFX_WRITE_LOW_16BIT(mask));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].mask2,
> > + IFX_WRITE_HIGH_16BIT(mask));
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb1,
> > + IFX_WRITE_LOW_16BIT(id));
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb2,
> > + (IF_ARB_MSGVAL | IFX_WRITE_HIGH_16BIT(id)));
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].msg_cntrl,
> mcont);
> > + ret = c_can_object_put(dev, iface, objno, IF_COMM_ALL &
> > + ~IF_COMM_TXRQST);
> > + if (ret < 0)
> > + return ret;
>
> Ditto.
Please see comment above.
> > +
> > + dev_dbg(dev->dev.parent, "obj no:%d, msgval:0x%08x\n", objno,
> > + c_can_read_reg32(priv, &priv->reg_base->msgval1));
> > +
> > + return 0;
> > +}
> > +
> > +static int c_can_inval_msg_object(struct net_device *dev, int iface,
> int objno)
> > +{
> > + int ret;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb1, 0);
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].arb2, 0);
> > + priv->write_reg(priv, &priv->reg_base->ifreg[iface].msg_cntrl,
> 0);
> > +
> > + ret = c_can_object_put(dev, iface, objno,
> > + IF_COMM_ARB | IF_COMM_CONTROL);
> > + if (ret < 0)
> > + return ret;
> > +
> > + dev_dbg(dev->dev.parent, "obj no:%d, msgval:0x%08x\n", objno,
> > + c_can_read_reg32(priv, &priv->reg_base->msgval1));
> > +
> > + return 0;
>
> Ditto.
Ditto.
> > +}
> > +
> > +static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
> > + struct net_device *dev)
> > +{
> > + u32 val;
> > + u32 msg_obj_no;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + struct can_frame *frame = (struct can_frame *)skb->data;
> > +
> > + if (can_dropped_invalid_skb(dev, skb))
> > + return NETDEV_TX_OK;
> > +
> > + msg_obj_no = get_tx_next_msg_obj(priv);
> > +
> > + /* prepare message object for transmission */
> > + val = c_can_write_msg_object(dev, 0, frame, msg_obj_no);
> > +
> > + /* enable interrupt for this message object */
> > + priv->write_reg(priv, &priv->reg_base->ifreg[0].msg_cntrl,
> > + IF_MCONT_TXIE | IF_MCONT_TXRQST | IF_MCONT_EOB |
> > + (val & 0xf));
> > + val = c_can_object_put(dev, 0, msg_obj_no, IF_COMM_ALL);
> > + if (val < 0)
> > + return val;
> > +
> > + can_put_echo_skb(skb, dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
> > +
> > + priv->tx_next++;
> > + if ((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0)
> > + netif_stop_queue(dev);
> > +
> > + return NETDEV_TX_OK;
> > +}
> > +
> > +static int c_can_set_bittiming(struct net_device *dev)
> > +{
> > + unsigned int reg_btr, reg_brpe, ctrl_save;
> > + u8 brp, brpe, sjw, tseg1, tseg2;
> > + u32 ten_bit_brp;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + const struct can_bittiming *bt = &priv->can.bittiming;
> > +
> > + /* c_can provides a 6-bit brp and 4-bit brpe fields */
> > + ten_bit_brp = bt->brp - 1;
> > + brp = ten_bit_brp & BTR_BRP_MASK;
> > + brpe = ten_bit_brp >> 6;
> > +
> > + sjw = bt->sjw - 1;
> > + tseg1 = bt->prop_seg + bt->phase_seg1 - 1;
> > + tseg2 = bt->phase_seg2 - 1;
> > +
> > + reg_btr = ((brp) | (sjw << BTR_SJW_SHIFT) | (tseg1 <<
> BTR_TSEG1_SHIFT) |
> > + (tseg2 << BTR_TSEG2_SHIFT));
> > +
> > + reg_brpe = brpe & BRP_EXT_BRPE_MASK;
> > +
> > + dev_dbg(dev->dev.parent,
> > + "brp = %d, brpe = %d, sjw = %d, seg1 = %d, seg2 =
> %d\n",
> > + brp, brpe, sjw, tseg1, tseg2);
> > + dev_dbg(dev->dev.parent, "setting BTR to %04x\n", reg_btr);
> > + dev_dbg(dev->dev.parent, "setting BRPE to %04x\n", reg_brpe);
>
> Like for the other drivers, could you please use one dev_info() here:
> dev_dbg(dev->dev.parent, "setting BTR=%04x BRPE=%04x\n", ...);
>
Ok. Will be done in V3
> > + ctrl_save = priv->read_reg(priv, &priv->reg_base->control);
> > + priv->write_reg(priv, &priv->reg_base->control,
> > + ctrl_save | CONTROL_CCE | CONTROL_INIT);
> > + priv->write_reg(priv, &priv->reg_base->btr, reg_btr);
> > + priv->write_reg(priv, &priv->reg_base->brp_ext, reg_brpe);
> > + priv->write_reg(priv, &priv->reg_base->control, ctrl_save);
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Configure C_CAN message objects for Tx and Rx purposes:
> > + * C_CAN provides a total of 32 message objects that can be
> configured
> > + * either for Tx or Rx purposes. Here the first 16 message objects
> are used as
> > + * a reception FIFO. The end of reception FIFO is signified by the
> EoB bit
> > + * being SET. The remaining 16 message objects are kept aside for Tx
> purposes.
> > + * See user guide document for further details on configuring
> message
> > + * objects.
> > + */
>
> Did you verify *in-order* transmisson and reception? You could use the
> canfdtest program from the can-utils.
I will check V3 for the same.
I also checked Marc's at91 driver and the
approach implemented there for in-order rx
object reception seems fine to me. If you and Marc agree I can
use the same here. Also I need to add credits for the same :)
> > +static int c_can_configure_msg_objects(struct net_device *dev)
> > +{
> > + int i;
> > +
> > + /* first invalidate all message objects */
> > + for (i = 0; i <= C_CAN_NO_OF_OBJECTS; i++)
> > + c_can_inval_msg_object(dev, 0, i);
> > +
> > + /* setup receive message objects */
> > + for (i = C_CAN_MSG_OBJ_RX_FIRST + 1 ; i < C_CAN_MSG_OBJ_RX_LAST;
> i++)
> > + c_can_setup_receive_object(dev, 0, i, 0, 0,
> > + ((IF_MCONT_RXIE | IF_MCONT_UMASK) & ~IF_MCONT_EOB));
> > +
> > + c_can_setup_receive_object(dev, 0, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
> > + IF_MCONT_EOB | IF_MCONT_RXIE | IF_MCONT_UMASK);
> > + return 0;
> > +}
> > +
> > +/*
> > + * Configure C_CAN chip:
> > + * - enable/disable auto-retransmission
> > + * - set operating mode
> > + * - configure message objects
> > + */
> > +static int c_can_chip_config(struct net_device *dev)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
> > + /* disable automatic retransmission */
> > + priv->write_reg(priv, &priv->reg_base->control,
> > + CONTROL_DISABLE_AR);
> > + else
> > + /* enable automatic retransmission */
> > + priv->write_reg(priv, &priv->reg_base->control,
> > + CONTROL_ENABLE_AR);
> > +
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
> > + /* loopback mode : useful for self-test function */
> > + priv->write_reg(priv, &priv->reg_base->control,
> (CONTROL_EIE |
> > + CONTROL_SIE | CONTROL_IE | CONTROL_TEST));
> > + priv->write_reg(priv, &priv->reg_base->test, TEST_LBACK);
> > + } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
> > + /* silent mode : bus-monitoring mode */
> > + priv->write_reg(priv, &priv->reg_base->control,
> (CONTROL_EIE |
> > + CONTROL_SIE | CONTROL_IE | CONTROL_TEST));
> > + priv->write_reg(priv, &priv->reg_base->test, TEST_SILENT);
> > + } else if (priv->can.ctrlmode & (CAN_CTRLMODE_LISTENONLY &
> > + CAN_CTRLMODE_LOOPBACK)) {
>
> As I see it, this case is never entered.
You are right. But as we discussed during the review of V1,
as the c_can core supports this mode (loopback + listen-only)
we should support the same in the driver as well.
> > + /* loopback + silent mode : useful for hot self-test */
> > + priv->write_reg(priv, &priv->reg_base->control,
> (CONTROL_EIE |
> > + CONTROL_SIE | CONTROL_IE | CONTROL_TEST));
> > + priv->write_reg(priv, &priv->reg_base->test,
> > + (TEST_LBACK | TEST_SILENT));
> > + } else
> > + /* normal mode*/
> > + priv->write_reg(priv, &priv->reg_base->control,
> > + (CONTROL_EIE | CONTROL_SIE | CONTROL_IE));
> > +
> > + /* configure message objects */
> > + c_can_configure_msg_objects(dev);
> > +
> > + return 0;
> > +}
> > +
> > +static int c_can_start(struct net_device *dev)
> > +{
> > + int err;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + /* enable status change, error and module interrupts */
> > + c_can_configure_interrupts(priv, ENABLE_ALL_INTERRUPTS);
> > +
> > + /* basic c_can configuration */
> > + err = c_can_chip_config(dev);
> > + if (err)
> > + return err;
> > +
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > +
> > + /* reset tx helper pointers */
> > + priv->tx_next = priv->tx_echo = 0;
> > +
> > + return 0;
> > +}
> > +
> > +static int c_can_stop(struct net_device *dev)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + /* disable all interrupts */
> > + c_can_configure_interrupts(priv, DISABLE_ALL_INTERRUPTS);
> > +
> > + /* set the state as STOPPED */
> > + priv->can.state = CAN_STATE_STOPPED;
> > +
> > + return 0;
> > +}
> > +
> > +static int c_can_set_mode(struct net_device *dev, enum can_mode
> mode)
> > +{
> > + switch (mode) {
> > + case CAN_MODE_START:
> > + c_can_start(dev);
> > + netif_wake_queue(dev);
> > + dev_info(dev->dev.parent,
> > + "c_can CAN_MODE_START requested\n");
>
> Please remove.
Ok.
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int c_can_get_state(const struct net_device *dev,
> > + enum can_state *state)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + *state = priv->can.state;
> > +
> > + return 0;
> > +}
>
> Please remove. This callback is only required if state changes cannot
> be
> mantained in the interrupt context.
Ok, V3 will handle this.
> > +static int c_can_get_berr_counter(const struct net_device *dev,
> > + struct can_berr_counter *bec)
> > +{
> > + unsigned int reg_err_counter;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + reg_err_counter = priv->read_reg(priv, &priv->reg_base-
> >error_counter);
> > + bec->rxerr = ((reg_err_counter & ERR_COUNTER_REC_MASK) >>
> > + ERR_COUNTER_REC_SHIFT);
> > + bec->txerr = (reg_err_counter & ERR_COUNTER_TEC_MASK);
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * theory of operation:
> > + *
> > + * priv->tx_echo holds the number of the oldest can_frame put for
> > + * transmission into the hardware, but not yet ACKed by the CAN tx
> > + * complete IRQ.
> > + *
> > + * We iterate from priv->tx_echo to priv->tx_next and check if the
> > + * packet has been transmitted, echo it back to the CAN framework.
> If
> > + * we discover a not yet transmitted package, stop looking for more.
> > + */
> > +static void c_can_do_tx(struct net_device *dev)
> > +{
> > + u32 val;
> > + u32 msg_obj_no;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + struct net_device_stats *stats = &dev->stats;
> > +
> > + for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv-
> >tx_echo++) {
> > + msg_obj_no = get_tx_echo_msg_obj(priv);
> > + c_can_inval_msg_object(dev, 0, msg_obj_no);
> > + val = c_can_read_reg32(priv, &priv->reg_base->txrqst1);
> > + if (!(val & (1 << msg_obj_no))) {
> > + can_get_echo_skb(dev,
> > + msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST);
> > + stats->tx_bytes += priv->read_reg(priv,
> > + &priv->reg_base->ifreg[0].msg_cntrl)
> > + & 0xF;
>
> Please use a #define for 0xf.
Ok.
> > + stats->tx_packets++;
> > + }
> > + }
> > +
> > + /* restart queue if wrap-up or if queue stalled on last pkt */
> > + if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
> > + ((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
> > + netif_wake_queue(dev);
> > +}
> > +
> > +/*
> > + * c_can_do_rx_poll - read multiple CAN messages from message
> objects
> > + */
> > +static int c_can_do_rx_poll(struct net_device *dev, int quota)
> > +{
> > + u32 num_rx_pkts = 0;
> > + unsigned int msg_obj;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + u32 val = c_can_read_reg32(priv, &priv->reg_base->newdat1);
> > +
> > + while (val & RECEIVE_OBJECT_BITS) {
> > + for (msg_obj = C_CAN_MSG_OBJ_RX_FIRST;
> > + msg_obj <= C_CAN_MSG_OBJ_RX_LAST; msg_obj++) {
> > + if (val & (1 << msg_obj)) {
> > + c_can_read_msg_object(dev, 0, msg_obj);
> > + num_rx_pkts++;
> > + quota--;
>
> Where do you handle quota?
Sorry but I didn't get your meaning here.
Everytime the rx_poll function is called quota is
decremented and num of rx packets received is incremented.
Am I missing something here?
> > + }
> > + }
> > +
> > + val = c_can_read_reg32(priv, &priv->reg_base->newdat1);
> > + }
> > +
> > + return num_rx_pkts;
> > +}
> > +
> > +static int c_can_err(struct net_device *dev,
> > + enum c_can_bus_error_types error_type,
> > + int lec_type)
> > +{
> > + unsigned int reg_err_counter;
> > + unsigned int rx_err_passive;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + struct net_device_stats *stats = &dev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > + struct can_berr_counter bec;
> > +
> > + /* propogate the error condition to the CAN stack */
> > + skb = alloc_can_err_skb(dev, &cf);
> > + if (unlikely(!skb))
> > + return 0;
> > +
> > + c_can_get_berr_counter(dev, &bec);
> > + reg_err_counter = priv->read_reg(priv, &priv->reg_base-
> >error_counter);
> > + rx_err_passive = ((reg_err_counter & ERR_COUNTER_RP_MASK) >>
> > + ERR_COUNTER_RP_SHIFT);
> > +
> > + if (error_type & C_CAN_ERROR_WARNING) {
> > + /* error warning state */
> > + priv->can.can_stats.error_warning++;
> > + priv->can.state = CAN_STATE_ERROR_WARNING;
> > + cf->can_id |= CAN_ERR_CRTL;
> > + if (bec.rxerr > 96)
> > + cf->data[1] = CAN_ERR_CRTL_RX_WARNING;
> > + if (bec.txerr > 96)
> > + cf->data[1] = CAN_ERR_CRTL_TX_WARNING;
> > + }
> > + if (error_type & C_CAN_ERROR_PASSIVE) {
> > + /* error passive state */
> > + priv->can.can_stats.error_passive++;
> > + priv->can.state = CAN_STATE_ERROR_PASSIVE;
> > + cf->can_id |= CAN_ERR_CRTL;
> > + if (rx_err_passive)
> > + cf->data[1] = CAN_ERR_CRTL_RX_PASSIVE;
> > + if (bec.txerr > 127)
> > + cf->data[1] = CAN_ERR_CRTL_TX_PASSIVE;
> > + }
> > + if (error_type & C_CAN_BUS_OFF) {
> > + /* bus-off state */
> > + priv->can.state = CAN_STATE_BUS_OFF;
> > + cf->can_id |= CAN_ERR_BUSOFF;
> > + /* disable all interrupts in bus-off mode to ensure that
> > + * the CPU is not hogged down
> > + */
> > + c_can_configure_interrupts(priv, DISABLE_ALL_INTERRUPTS);
> > + can_bus_off(dev);
> > + }
> > +
> > + /* check for 'last error code' which tells us the
> > + * type of the last error to occur on the CAN bus
> > + */
> > + if (lec_type) {
> > + /* common for all type of bus errors */
> > + priv->can.can_stats.bus_error++;
> > + stats->rx_errors++;
> > + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> > + cf->data[2] |= CAN_ERR_PROT_UNSPEC;
> > +
> > + if (lec_type & LEC_STUFF_ERROR) {
> > + dev_info(dev->dev.parent, "stuff error\n");
> > + cf->data[2] |= CAN_ERR_PROT_STUFF;
> > + }
> > + if (lec_type & LEC_FORM_ERROR) {
> > + dev_info(dev->dev.parent, "form error\n");
> > + cf->data[2] |= CAN_ERR_PROT_FORM;
> > + }
> > + if (lec_type & LEC_ACK_ERROR) {
> > + dev_info(dev->dev.parent, "ack error\n");
> > + cf->data[2] |= (CAN_ERR_PROT_LOC_ACK |
> > + CAN_ERR_PROT_LOC_ACK_DEL);
> > + }
> > + if (lec_type & LEC_BIT1_ERROR) {
> > + dev_info(dev->dev.parent, "bit1 error\n");
> > + cf->data[2] |= CAN_ERR_PROT_BIT1;
> > + }
> > + if (lec_type & LEC_BIT0_ERROR) {
> > + dev_info(dev->dev.parent, "bit0 error\n");
> > + cf->data[2] |= CAN_ERR_PROT_BIT0;
> > + }
> > + if (lec_type & LEC_CRC_ERROR) {
> > + dev_info(dev->dev.parent, "CRC error\n");
>
> Please use dev_dbg() here and above
Ok.
> > + cf->data[2] |= (CAN_ERR_PROT_LOC_CRC_SEQ |
> > + CAN_ERR_PROT_LOC_CRC_DEL);
> > + }
> > + }
>
> The lec should be handled by a switch statement. Also, please use
> dev_dbg in favor of dev_info.
But as I have seen on the board, there can be multiple lec bits
set at a time (e.g. shorting CAN TX and RX lines). In such cases the
multiple-if structure handles the same. Do you agree?
> > + netif_receive_skb(skb);
> > + stats->rx_packets++;
> > + stats->rx_bytes += cf->can_dlc;
> > +
> > + return 1;
> > +}
> > +
> > +static int c_can_poll(struct napi_struct *napi, int quota)
> > +{
> > + u16 irqstatus;
> > + int lec_type = 0;
> > + int work_done = 0;
> > + struct net_device *dev = napi->dev;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + enum c_can_bus_error_types error_type = C_CAN_NO_ERROR;
> > +
> > + irqstatus = priv->read_reg(priv, &priv->reg_base->ir);
> > +
> > + /* status events have the highest priority */
> > + if (irqstatus == STATUS_INTERRUPT) {
> > + priv->current_status = priv->read_reg(priv,
> > + &priv->reg_base->status);
> > +
> > + /* handle Tx/Rx events */
> > + if (priv->current_status & STATUS_TXOK)
> > + priv->write_reg(priv, &priv->reg_base->status,
> > + (priv->current_status & ~STATUS_TXOK));
> > +
> > + if (priv->current_status & STATUS_RXOK)
> > + priv->write_reg(priv, &priv->reg_base->status,
> > + (priv->current_status & ~STATUS_RXOK));
> > +
> > + /* handle bus error events */
> > + if (priv->current_status & STATUS_EWARN) {
> > + dev_info(dev->dev.parent,
> > + "entered error warning state\n");
> > + error_type = C_CAN_ERROR_WARNING;
> > + }
> > + if ((priv->current_status & STATUS_EPASS) &&
> > + (!(priv->last_status & STATUS_EPASS))) {
> > + dev_info(dev->dev.parent,
> > + "entered error passive state\n");
> > + error_type = C_CAN_ERROR_PASSIVE;
> > + }
> > + if ((priv->current_status & STATUS_BOFF) &&
> > + (!(priv->last_status & STATUS_BOFF))) {
> > + dev_info(dev->dev.parent,
> > + "entered bus off state\n");
> > + error_type = C_CAN_BUS_OFF;
> > + }
> > + if (priv->current_status & STATUS_LEC_MASK)
> > + lec_type = (priv->current_status & STATUS_LEC_MASK);
> > +
> > + /* handle bus recovery events */
> > + if ((!(priv->current_status & STATUS_EPASS)) &&
> > + (priv->last_status & STATUS_EPASS)) {
> > + dev_info(dev->dev.parent,
> > + "left error passive state\n");
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > + }
> > + if ((!(priv->current_status & STATUS_BOFF)) &&
> > + (priv->last_status & STATUS_BOFF)) {
> > + dev_info(dev->dev.parent,
> > + "left bus off state\n");
>
> Please use dev_dbg here and above.
Ok.
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > + }
> > +
> > + priv->last_status = priv->current_status;
> > +
> > + /* handle error on the bus */
> > + if (error_type != C_CAN_NO_ERROR)
> > + work_done += c_can_err(dev, error_type, lec_type);
> > + } else if ((irqstatus > C_CAN_MSG_OBJ_RX_FIRST) &&
> > + (irqstatus <= C_CAN_MSG_OBJ_RX_LAST)) {
> > + /* handle events corresponding to receive message objects
> */
> > + work_done += c_can_do_rx_poll(dev, (quota - work_done));
> > + quota--;
>
> Why do you decrement quota here?
Oops. Will be corrected in V3
> > + } else if ((irqstatus > C_CAN_MSG_OBJ_TX_FIRST) &&
> > + (irqstatus <= C_CAN_MSG_OBJ_TX_LAST)) {
> > + /* handle events corresponding to transmit message objects
> */
> > + c_can_do_tx(dev);
> > + }
> > +
> > + if (work_done < quota) {
> > + napi_complete(napi);
> > + /* enable all IRQs */
> > + c_can_configure_interrupts(priv, ENABLE_ALL_INTERRUPTS);
> > + }
> > +
> > + return work_done;
> > +}
> > +
> > +static irqreturn_t c_can_isr(int irq, void *dev_id)
> > +{
> > + struct net_device *dev = (struct net_device *)dev_id;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + /* disable all interrupts and schedule the NAPI */
> > + c_can_configure_interrupts(priv, DISABLE_ALL_INTERRUPTS);
> > + napi_schedule(&priv->napi);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int c_can_open(struct net_device *dev)
> > +{
> > + int err;
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + /* open the can device */
> > + err = open_candev(dev);
> > + if (err) {
> > + dev_err(dev->dev.parent, "failed to open can device\n");
> > + return err;
> > + }
> > +
> > + /* register interrupt handler */
> > + err = request_irq(dev->irq, &c_can_isr, priv->irq_flags, dev-
> >name,
> > + (void *)dev);
>
> I don't think you need the (void *) cast.
Ok.
> > + if (err < 0) {
> > + dev_err(dev->dev.parent, "failed to attach interrupt\n");
> > + goto exit_irq_fail;
> > + }
> > +
> > + /* start the c_can controller */
> > + err = c_can_start(dev);
> > + if (err)
> > + goto exit_start_fail;
> > + napi_enable(&priv->napi);
> > +
> > + netif_start_queue(dev);
> > +
> > + return 0;
> > +
> > +exit_start_fail:
> > + free_irq(dev->irq, dev);
> > +exit_irq_fail:
> > + close_candev(dev);
> > + return err;
> > +}
> > +
> > +static int c_can_close(struct net_device *dev)
> > +{
> > + struct c_can_priv *priv = netdev_priv(dev);
> > +
> > + netif_stop_queue(dev);
> > + napi_disable(&priv->napi);
> > + c_can_stop(dev);
> > + free_irq(dev->irq, dev);
> > + close_candev(dev);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct net_device_ops c_can_netdev_ops = {
> > + .ndo_open = c_can_open,
> > + .ndo_stop = c_can_close,
> > + .ndo_start_xmit = c_can_start_xmit,
> > +};
> > +
> > +static int c_can_probe(struct platform_device *pdev)
>
> Please use __devinit ...
Ok.
> > +{
> > + int ret;
> > + void __iomem *addr;
> > + struct net_device *dev;
> > + struct c_can_priv *priv;
> > + struct resource *mem, *irq;
> > + struct clk *clk;
> > +
> > + /* get the appropriate clk */
> > + clk = clk_get(&pdev->dev, NULL);
> > + if (IS_ERR(clk)) {
> > + dev_err(&pdev->dev, "no clock defined\n");
> > + ret = -ENODEV;
> > + goto exit;
> > + }
> > +
> > + /* get the platform data */
> > + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> > + if (!mem || (irq <= 0)) {
> > + ret = -ENODEV;
> > + goto exit_free_clk;
> > + }
> > +
> > + if (!request_mem_region(mem->start, resource_size(mem),
> DRV_NAME)) {
> > + dev_err(&pdev->dev, "resource unavailable\n");
> > + ret = -ENODEV;
> > + goto exit_free_clk;
> > + }
> > +
> > + addr = ioremap(mem->start, resource_size(mem));
> > + if (!addr) {
> > + dev_err(&pdev->dev, "failed to map can port\n");
> > + ret = -ENOMEM;
> > + goto exit_release_mem;
> > + }
> > +
> > + /* allocate the c_can device */
> > + dev = alloc_candev(sizeof(struct c_can_priv),
> C_CAN_MSG_OBJ_TX_NUM);
> > + if (!dev) {
> > + ret = -ENOMEM;
> > + goto exit_iounmap;
> > + }
> > +
> > + priv = netdev_priv(dev);
> > +
> > + priv->irq_flags = irq->flags;
> > + priv->reg_base = addr;
> > + priv->can.clock.freq = clk_get_rate(clk);
> > + priv->clk = clk;
> > +
> > + switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
> > + case IORESOURCE_MEM_32BIT:
> > + priv->read_reg = c_can_read_reg_aligned_to_32bit;
> > + priv->write_reg = c_can_write_reg_aligned_to_32bit;
> > + break;
> > + case IORESOURCE_MEM_16BIT:
> > + default:
> > + priv->read_reg = c_can_read_reg_aligned_to_16bit;
> > + priv->write_reg = c_can_write_reg_aligned_to_16bit;
> > + break;
> > + }
> > +
> > + priv->dev = dev;
> > + priv->can.bittiming_const = &c_can_bittiming_const;
> > + priv->can.do_set_bittiming = c_can_set_bittiming;
> > + priv->can.do_get_state = c_can_get_state;
> > + priv->can.do_set_mode = c_can_set_mode;
> > + priv->can.do_get_berr_counter = c_can_get_berr_counter;
> > + priv->can.ctrlmode_supported = CAN_CTRLMODE_ONE_SHOT |
> > + CAN_CTRLMODE_LOOPBACK |
> > + CAN_CTRLMODE_LISTENONLY |
> > + CAN_CTRLMODE_BERR_REPORTING;
>
> Where is CAN_CTRLMODE_BERR_REPORTING implemented? Note that it has
> nothing to do with do_get_berr_counter. Please check the SJA1000
> driver:
>
> http://lxr.linux.no/#linux+v2.6.36/drivers/net/can/sja1000/sja1000.c#L1
> 46
>
> Bus error handling can be requested by the user via netlink interface.
>
> # ip link set canX type can ... berr-reporting on
>
> The driver then usually enables the bus error interrupts. I just
> realize
> that Documentation/networking/can.txt is not up-to-date. I will provide
> a patch a.s.a.p.
Yes, I have seen the sja1000 implementation before preparing V2.
But unfortunately the c_can core does not also only the bus-error-reporting
to be masked/unmasked. There are three interrupt masks available in the
Control register:
a) Error Interrupt Enable
If Enabled - A change in the bits BOff or EWarn in the Status Register will
generate an interrupt.
b) Status Change Interrupt Enable
If Enabled - An interrupt will be generated when a message transfer is
successfully completed or a CAN bus error is detected.
c) Module Interrupt Enable
If Enabled - Interrupts will set IRQ_B to LOW.
> > + netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
> > +
> > + dev->irq = irq->start;
> > + dev->flags |= IFF_ECHO; /* we support local echo */
> > + dev->netdev_ops = &c_can_netdev_ops;
> > + platform_set_drvdata(pdev, dev);
> > + SET_NETDEV_DEV(dev, &pdev->dev);
> > +
> > + ret = register_candev(dev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
> > + DRV_NAME, ret);
> > + goto exit_free_device;
> > + }
> > +
> > + dev_info(&pdev->dev, "%s device registered (reg_base=%p,
> irq=%d)\n",
> > + DRV_NAME, priv->reg_base, dev->irq);
> > + return 0;
> > +
> > +exit_free_device:
> > + platform_set_drvdata(pdev, NULL);
> > + free_candev(dev);
> > +exit_iounmap:
> > + iounmap(addr);
> > +exit_release_mem:
> > + release_mem_region(mem->start, resource_size(mem));
> > +exit_free_clk:
> > + clk_put(clk);
> > +exit:
> > + dev_err(&pdev->dev, "probe failed\n");
> > +
> > + return ret;
> > +}
> > +
> > +static int c_can_remove(struct platform_device *pdev)
>
> ... and __devexit.
Ok.
> > +{
> > + struct net_device *dev = platform_get_drvdata(pdev);
> > + struct c_can_priv *priv = netdev_priv(dev);
> > + struct resource *mem;
> > +
> > + /* disable all interrupts */
> > + c_can_configure_interrupts(priv, DISABLE_ALL_INTERRUPTS);
> > +
> > + unregister_candev(dev);
> > + platform_set_drvdata(pdev, NULL);
> > +
> > + free_candev(dev);
> > + iounmap(priv->reg_base);
> > +
> > + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + release_mem_region(mem->start, resource_size(mem));
> > +
> > + clk_put(priv->clk);
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver c_can_driver = {
> > + .driver = {
> > + .name = DRV_NAME,
> > + .owner = THIS_MODULE,
> > + },
> > + .probe = c_can_probe,
> > + .remove = c_can_remove,
>
> Please use __devexit_p.
Ok.
> > +};
>
> No "=" alignment please.
Ok.
> > +static int __init c_can_init(void)
> > +{
> > + return platform_driver_register(&c_can_driver);
> > +}
> > +module_init(c_can_init);
> > +
> > +static void __exit c_can_exit(void)
> > +{
> > + platform_driver_unregister(&c_can_driver);
> > +}
> > +module_exit(c_can_exit);
> > +
> > +MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@...com>");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("CAN bus driver for Bosch C_CAN controller");
>
> You could also use the new netdev_dbg and friends instead of
> dev_dbg(dev->dev.parent, ...).
Ok.
> Thanks for you contribution.
>
> Wolfgang.
Regards,
Bhupesh
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