Re: [PATCH] can: kvaser_usb: get CAN clock frequency from device

Hi,

I'm not familiar with the tag conventions used in the stable tree. This is a backport of upstream commit fb12797ab1fef480ad8a32a30984844444eeb00d, for stable 4.4, 4.9 and 4.14. How to properly specify this?

Best regards, jimmy

On 2021-12-22 01:28, Jimmy Assarsson wrote:

commit fb12797ab1fef480ad8a32a30984844444eeb00d upstream.

The CAN clock frequency is used when calculating the CAN bittiming parameters. When wrong clock frequency is used, the device may end up with wrong bittiming parameters, depending on user requested bittiming parameters.

To avoid this, get the CAN clock frequency from the device. Various existing Kvaser Leaf products use different CAN clocks.

Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices") Link: https://lore.kernel.org/all/20211208152122.250852-2-extja@kvaser.com Cc: stable@vger.kernel.org Signed-off-by: Jimmy Assarsson extja@kvaser.com [backport note: kvaser_usb was split into multiple files in 4.19]

---

drivers/net/can/usb/kvaser_usb.c | 41 ++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c index 9991ee93735a..81abb30d9ec0 100644 --- a/drivers/net/can/usb/kvaser_usb.c +++ b/drivers/net/can/usb/kvaser_usb.c @@ -31,7 +31,10 @@ #define USB_SEND_TIMEOUT 1000 /* msecs */ #define USB_RECV_TIMEOUT 1000 /* msecs */ #define RX_BUFFER_SIZE 3072 -#define CAN_USB_CLOCK 8000000 +#define KVASER_USB_CAN_CLOCK_8MHZ 8000000 +#define KVASER_USB_CAN_CLOCK_16MHZ 16000000 +#define KVASER_USB_CAN_CLOCK_24MHZ 24000000 +#define KVASER_USB_CAN_CLOCK_32MHZ 32000000 #define MAX_NET_DEVICES 3 #define MAX_USBCAN_NET_DEVICES 2 @@ -139,6 +142,12 @@ static inline bool kvaser_is_usbcan(const struct usb_device_id *id) #define CMD_LEAF_USB_THROTTLE 77 #define CMD_LEAF_LOG_MESSAGE 106 +/* Leaf frequency options */ +#define KVASER_USB_LEAF_SWOPTION_FREQ_MASK 0x60 +#define KVASER_USB_LEAF_SWOPTION_FREQ_16_MHZ_CLK 0 +#define KVASER_USB_LEAF_SWOPTION_FREQ_32_MHZ_CLK BIT(5) +#define KVASER_USB_LEAF_SWOPTION_FREQ_24_MHZ_CLK BIT(6)

• /* error factors */ #define M16C_EF_ACKE BIT(0) #define M16C_EF_CRCE BIT(1)

@@ -469,6 +478,8 @@ struct kvaser_usb { bool rxinitdone; void *rxbuf[MAX_RX_URBS]; dma_addr_t rxbuf_dma[MAX_RX_URBS];

• struct can_clock clock; };

struct kvaser_usb_net_priv { @@ -646,6 +657,27 @@ static int kvaser_usb_send_simple_msg(const struct kvaser_usb *dev, return rc; } +static void kvaser_usb_get_software_info_leaf(struct kvaser_usb *dev,

• 			      const struct leaf_msg_softinfo *softinfo)
  

+{

• u32 sw_options = le32_to_cpu(softinfo->sw_options);
• dev->fw_version = le32_to_cpu(softinfo->fw_version);
• dev->max_tx_urbs = le16_to_cpu(softinfo->max_outstanding_tx);
• switch (sw_options & KVASER_USB_LEAF_SWOPTION_FREQ_MASK) {
• case KVASER_USB_LEAF_SWOPTION_FREQ_16_MHZ_CLK:

• dev->clock.freq = KVASER_USB_CAN_CLOCK_16MHZ;
  

• break;
  

• case KVASER_USB_LEAF_SWOPTION_FREQ_24_MHZ_CLK:

• dev->clock.freq = KVASER_USB_CAN_CLOCK_24MHZ;
  

• break;
  

• case KVASER_USB_LEAF_SWOPTION_FREQ_32_MHZ_CLK:

• dev->clock.freq = KVASER_USB_CAN_CLOCK_32MHZ;
  

• break;
  

• }

+}

• static int kvaser_usb_get_software_info(struct kvaser_usb *dev) { struct kvaser_msg msg;

@@ -661,14 +693,13 @@ static int kvaser_usb_get_software_info(struct kvaser_usb *dev) switch (dev->family) { case KVASER_LEAF:

• dev->fw_version = le32_to_cpu(msg.u.leaf.softinfo.fw_version);
  

• dev->max_tx_urbs =
  

• 	le16_to_cpu(msg.u.leaf.softinfo.max_outstanding_tx);
  

• kvaser_usb_get_software_info_leaf(dev, &msg.u.leaf.softinfo);
  

  break; case KVASER_USBCAN: dev->fw_version = le32_to_cpu(msg.u.usbcan.softinfo.fw_version); dev->max_tx_urbs = le16_to_cpu(msg.u.usbcan.softinfo.max_outstanding_tx);

• dev->clock.freq = KVASER_USB_CAN_CLOCK_8MHZ;
  

  break; }

@@ -1925,7 +1956,7 @@ static int kvaser_usb_init_one(struct usb_interface *intf, kvaser_usb_reset_tx_urb_contexts(priv); priv->can.state = CAN_STATE_STOPPED;

• priv->can.clock.freq = CAN_USB_CLOCK;

• priv->can.clock.freq = dev->clock.freq; priv->can.bittiming_const = &kvaser_usb_bittiming_const; priv->can.do_set_bittiming = kvaser_usb_set_bittiming; priv->can.do_set_mode = kvaser_usb_set_mode;