63dfe07096
ISO 11898-1 specifies in section 11.3.3 "Transmitter delay
compensation" that "the configuration range for [the] SSP position
shall be at least 0 to 63 minimum time quanta."
Because SSP = TDCV + TDCO, it means that we should allow both TDCV and
TDCO to hold zero value in order to honor SSP's minimum possible
value.
However, current implementation assigned special meaning to TDCV and
TDCO's zero values:
* TDCV = 0 -> TDCV is automatically measured by the transceiver.
* TDCO = 0 -> TDC is off.
In order to allow for those values to really be zero and to maintain
current features, we introduce two new flags:
* CAN_CTRLMODE_TDC_AUTO indicates that the controller support
automatic measurement of TDCV.
* CAN_CTRLMODE_TDC_MANUAL indicates that the controller support
manual configuration of TDCV. N.B.: current implementation failed
to provide an option for the driver to indicate that only manual
mode was supported.
TDC is disabled if both CAN_CTRLMODE_TDC_AUTO and
CAN_CTRLMODE_TDC_MANUAL flags are off, c.f. the helper function
can_tdc_is_enabled() which is also introduced in this patch.
Also, this patch adds three fields: tdcv_min, tdco_min and tdcf_min to
struct can_tdc_const. While we are not convinced that those three
fields could be anything else than zero, we can imagine that some
controllers might specify a lower bound on these. Thus, those minimums
are really added "just in case".
Comments of struct can_tdc and can_tdc_const are updated accordingly.
Finally, the changes are applied to the etas_es58x driver.
Link: https://lore.kernel.org/all/20210918095637.20108-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
156 lines
4.3 KiB
C
156 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* linux/can/dev.h
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*
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* Definitions for the CAN network device driver interface
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*
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* Copyright (C) 2006 Andrey Volkov <avolkov@varma-el.com>
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* Varma Electronics Oy
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*
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* Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
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*
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*/
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#ifndef _CAN_DEV_H
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#define _CAN_DEV_H
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#include <linux/can.h>
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#include <linux/can/bittiming.h>
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#include <linux/can/error.h>
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#include <linux/can/led.h>
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#include <linux/can/length.h>
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#include <linux/can/netlink.h>
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#include <linux/can/skb.h>
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#include <linux/netdevice.h>
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/*
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* CAN mode
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*/
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enum can_mode {
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CAN_MODE_STOP = 0,
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CAN_MODE_START,
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CAN_MODE_SLEEP
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};
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enum can_termination_gpio {
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CAN_TERMINATION_GPIO_DISABLED = 0,
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CAN_TERMINATION_GPIO_ENABLED,
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CAN_TERMINATION_GPIO_MAX,
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};
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/*
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* CAN common private data
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*/
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struct can_priv {
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struct net_device *dev;
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struct can_device_stats can_stats;
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const struct can_bittiming_const *bittiming_const,
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*data_bittiming_const;
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struct can_bittiming bittiming, data_bittiming;
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const struct can_tdc_const *tdc_const;
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struct can_tdc tdc;
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unsigned int bitrate_const_cnt;
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const u32 *bitrate_const;
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const u32 *data_bitrate_const;
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unsigned int data_bitrate_const_cnt;
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u32 bitrate_max;
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struct can_clock clock;
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unsigned int termination_const_cnt;
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const u16 *termination_const;
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u16 termination;
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struct gpio_desc *termination_gpio;
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u16 termination_gpio_ohms[CAN_TERMINATION_GPIO_MAX];
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enum can_state state;
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/* CAN controller features - see include/uapi/linux/can/netlink.h */
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u32 ctrlmode; /* current options setting */
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u32 ctrlmode_supported; /* options that can be modified by netlink */
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u32 ctrlmode_static; /* static enabled options for driver/hardware */
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int restart_ms;
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struct delayed_work restart_work;
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int (*do_set_bittiming)(struct net_device *dev);
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int (*do_set_data_bittiming)(struct net_device *dev);
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int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
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int (*do_set_termination)(struct net_device *dev, u16 term);
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int (*do_get_state)(const struct net_device *dev,
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enum can_state *state);
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int (*do_get_berr_counter)(const struct net_device *dev,
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struct can_berr_counter *bec);
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unsigned int echo_skb_max;
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struct sk_buff **echo_skb;
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#ifdef CONFIG_CAN_LEDS
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struct led_trigger *tx_led_trig;
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char tx_led_trig_name[CAN_LED_NAME_SZ];
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struct led_trigger *rx_led_trig;
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char rx_led_trig_name[CAN_LED_NAME_SZ];
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struct led_trigger *rxtx_led_trig;
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char rxtx_led_trig_name[CAN_LED_NAME_SZ];
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#endif
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};
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static inline bool can_tdc_is_enabled(const struct can_priv *priv)
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{
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return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK);
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}
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/* helper to define static CAN controller features at device creation time */
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static inline void can_set_static_ctrlmode(struct net_device *dev,
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u32 static_mode)
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{
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struct can_priv *priv = netdev_priv(dev);
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/* alloc_candev() succeeded => netdev_priv() is valid at this point */
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priv->ctrlmode = static_mode;
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priv->ctrlmode_static = static_mode;
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/* override MTU which was set by default in can_setup()? */
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if (static_mode & CAN_CTRLMODE_FD)
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dev->mtu = CANFD_MTU;
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}
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void can_setup(struct net_device *dev);
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struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
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unsigned int txqs, unsigned int rxqs);
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#define alloc_candev(sizeof_priv, echo_skb_max) \
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alloc_candev_mqs(sizeof_priv, echo_skb_max, 1, 1)
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#define alloc_candev_mq(sizeof_priv, echo_skb_max, count) \
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alloc_candev_mqs(sizeof_priv, echo_skb_max, count, count)
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void free_candev(struct net_device *dev);
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/* a candev safe wrapper around netdev_priv */
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struct can_priv *safe_candev_priv(struct net_device *dev);
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int open_candev(struct net_device *dev);
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void close_candev(struct net_device *dev);
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int can_change_mtu(struct net_device *dev, int new_mtu);
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int register_candev(struct net_device *dev);
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void unregister_candev(struct net_device *dev);
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int can_restart_now(struct net_device *dev);
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void can_bus_off(struct net_device *dev);
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const char *can_get_state_str(const enum can_state state);
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void can_change_state(struct net_device *dev, struct can_frame *cf,
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enum can_state tx_state, enum can_state rx_state);
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#ifdef CONFIG_OF
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void of_can_transceiver(struct net_device *dev);
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#else
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static inline void of_can_transceiver(struct net_device *dev) { }
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#endif
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extern struct rtnl_link_ops can_link_ops;
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int can_netlink_register(void);
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void can_netlink_unregister(void);
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#endif /* !_CAN_DEV_H */
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