[PATCH 4.19 027/321] can: c_can: D_CAN: c_can_chip_config(): perform a sofware reset on open

Greg Kroah-Hartman
2019-12-03T23:08:07Z

From: Jeroen Hofstee <jhofstee@victronenergy.com>

[ Upstream commit 23c5a9488f076bab336177cd1d1a366bd8ddf087 ]

When the CAN interface is closed it the hardwre is put in power down
mode, but does not reset the error counters / state. Reset the D_CAN on
open, so the reported state and the actual state match.

According to [1], the C_CAN module doesn't have the software reset.

[1] http://www.bosch-semiconductors.com/media/ip_modules/pdf_2/c_can_fd8/users_manual_c_can_fd8_r210_1.pdf

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/can/c_can/c_can.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 9b61bfbea6cd1..24c6015f6c92b 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -52,6 +52,7 @@
#define CONTROL_EX_PDR BIT(8)

/* control register */
+#define CONTROL_SWR BIT(15)
#define CONTROL_TEST BIT(7)
#define CONTROL_CCE BIT(6)
#define CONTROL_DISABLE_AR BIT(5)
@@ -572,6 +573,26 @@ static void c_can_configure_msg_objects(struct net_device *dev)
IF_MCONT_RCV_EOB);
}

+static int c_can_software_reset(struct net_device *dev)
+{
+ struct c_can_priv *priv = netdev_priv(dev);
+ int retry = 0;
+
+ if (priv->type != BOSCH_D_CAN)
+ return 0;
+
+ priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_SWR | CONTROL_INIT);
+ while (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_SWR) {
+ msleep(20);
+ if (retry++ > 100) {
+ netdev_err(dev, "CCTRL: software reset failed\n");
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+
/*
* Configure C_CAN chip:
* - enable/disable auto-retransmission
@@ -581,6 +602,11 @@ static void c_can_configure_msg_objects(struct net_device *dev)
static int c_can_chip_config(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
+ int err;
+
+ err = c_can_software_reset(dev);
+ if (err)
+ return err;

/* enable automatic retransmission */
priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR);
--
2.20.1