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Message-ID: <D5ECB3C7A6F99444980976A8C6D896384DEAFA3066@EAPEX1MAIL1.st.com>
Date: Wed, 12 Jan 2011 11:30:54 +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>,
David Miller <davem@...emloft.net>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: RE: [PATCH net-next-2.6 v4 1/1] can: c_can: Added support for Bosch
C_CAN controller
Hi Wolfgang,
> -----Original Message-----
> From: Wolfgang Grandegger [mailto:wg@...ndegger.com]
> Hi Bhupesh,
>
> some final nitpicking as you need to fix Marc remarks anyway...
>
> On 01/11/2011 12:49 PM, 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/media/en/pdf/ipmodules_1/
> > c_can/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 V3:
> > 1. Corrected commenting style.
> > 2. Removing *non-required* header files from driver files.
> > 3. Removed extra *non-required* outer brackets globally.
> > 4. Implemented and used a inline routine to check BUSY status.
> > 5. Added a board-specific param *priv* inside the c_can_priv struct.
> >
> > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...com>
>
> ...
> > +++ b/drivers/net/can/c_can/c_can.h
> > @@ -0,0 +1,235 @@
> > +/*
> > + * 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>
> > + *
> > + * TX and RX NAPI implementation has been borrowed from at91 CAN
> driver
> > + * written by:
> > + * Copyright
> > + * (C) 2007 by Hans J. Koch <hjk@...utronix.de>
> > + * (C) 2008, 2009 by Marc Kleine-Budde <kernel@...gutronix.de>
> > + *
> > + * 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/media/en/pdf/ipmodules_1/c_can/
> > + * 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.
> > + */
> > +
> > +#ifndef C_CAN_H
> > +#define C_CAN_H
> > +
> > +/* control register */
> > +#define CONTROL_TEST BIT(7)
> > +#define CONTROL_CCE BIT(6)
> > +#define CONTROL_DISABLE_AR BIT(5)
> > +#define CONTROL_ENABLE_AR (0 << 5)
> > +#define CONTROL_EIE BIT(3)
> > +#define CONTROL_SIE BIT(2)
> > +#define CONTROL_IE BIT(1)
> > +#define CONTROL_INIT BIT(0)
> > +
> > +/* test register */
> > +#define TEST_RX BIT(7)
> > +#define TEST_TX1 BIT(6)
> > +#define TEST_TX2 BIT(5)
> > +#define TEST_LBACK BIT(4)
> > +#define TEST_SILENT BIT(3)
> > +#define TEST_BASIC BIT(2)
> > +
> > +/* status register */
> > +#define STATUS_BOFF BIT(7)
> > +#define STATUS_EWARN BIT(6)
> > +#define STATUS_EPASS BIT(5)
> > +#define STATUS_RXOK BIT(4)
> > +#define STATUS_TXOK BIT(3)
> > +#define STATUS_LEC_MASK 0x07
> > +
> > +/* error counter register */
> > +#define ERR_COUNTER_TEC_MASK 0xff
> > +#define ERR_COUNTER_TEC_SHIFT 0
> > +#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)
>
> s/ERR_COUNTER/ERR_CNT/ to match the member name.
Ok.
> > +
> > +/* 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 BIT(15)
> > +
> > +/* IFx command mask */
> > +#define IF_COMM_WR BIT(7)
> > +#define IF_COMM_MASK BIT(6)
> > +#define IF_COMM_ARB BIT(5)
> > +#define IF_COMM_CONTROL BIT(4)
> > +#define IF_COMM_CLR_INT_PND BIT(3)
> > +#define IF_COMM_TXRQST BIT(2)
> > +#define IF_COMM_DATAA BIT(1)
> > +#define IF_COMM_DATAB BIT(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 BIT(15)
> > +#define IF_ARB_MSGXTD BIT(14)
> > +#define IF_ARB_TRANSMIT BIT(13)
> > +
> > +/* IFx message control */
> > +#define IF_MCONT_NEWDAT BIT(15)
> > +#define IF_MCONT_MSGLST BIT(14)
> > +#define IF_MCONT_CLR_MSGLST (0 << 14)
> > +#define IF_MCONT_INTPND BIT(13)
> > +#define IF_MCONT_UMASK BIT(12)
> > +#define IF_MCONT_TXIE BIT(11)
> > +#define IF_MCONT_RXIE BIT(10)
> > +#define IF_MCONT_RMTEN BIT(9)
> > +#define IF_MCONT_TXRQST BIT(8)
> > +#define IF_MCONT_EOB BIT(7)
> > +#define IF_MCONT_DLC_MASK 0xf
> > +
> > +/*
> > + * 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_MSG_OBJ_RX_SPLIT 8
> > +#define C_CAN_MSG_RX_LOW_LAST (C_CAN_MSG_OBJ_RX_SPLIT - 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
> > +
> > +/* global interrupt masks */
> > +#define ENABLE_ALL_INTERRUPTS 1
> > +#define DISABLE_ALL_INTERRUPTS 0
> > +
> > +/* minimum timeout for checking BUSY status */
> > +#define MIN_TIMEOUT_VALUE 6
> > +
> > +/* 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[4];
> > + u16 _reserved[13];
> > +};
> > +
> > +/* c_can hardware registers */
> > +struct c_can_regs {
> > + u16 control;
> > + u16 status;
> > + u16 err_cnt;
> > + u16 btr;
> > + u16 interrupt;
> > + u16 test;
> > + u16 brp_ext;
> > + u16 _reserved1;
> > + struct c_can_if_regs intf[2]; /* [0] = IF1 and [1] = IF2 */
>
> I not happy with the name "intf". Sounds more like an interrupt related
> property. Above you already use the prefix IF_ for the corresponding
> macro definitions and somewhere else the name "iface".
I tried using the name *if* suggested by you here but the compiler will complain
considering it as a usage of if-construct. Do you have a better name that we
can use here?
Regards,
Bhupesh
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