@@ -379,38 +379,72 @@ m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset, u32 *val)
return cdev->ops->read_fifo(cdev, addr_offset, val, 1);
}
-static void m_can_config_endisable(struct m_can_classdev *cdev, bool enable)
+static int m_can_cccr_update_bits(struct m_can_classdev *cdev, u32 mask, u32 val)
{
- u32 cccr = m_can_read(cdev, M_CAN_CCCR);
- u32 timeout = 10;
- u32 val = 0;
+ u32 val_before = m_can_read(cdev, M_CAN_CCCR);
+ u32 val_after = (val_before & ~mask) | val;
+ size_t tries = 10;
- /* Clear the Clock stop request if it was set */
- if (cccr & CCCR_CSR)
- cccr &= ~CCCR_CSR;
-
- if (enable) {
- /* enable m_can configuration */
- m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT);
- udelay(5);
- /* CCCR.CCE can only be set/reset while CCCR.INIT = '1' */
- m_can_write(cdev, M_CAN_CCCR, cccr | CCCR_INIT | CCCR_CCE);
- } else {
- m_can_write(cdev, M_CAN_CCCR, cccr & ~(CCCR_INIT | CCCR_CCE));
+ if (!(mask & CCCR_INIT) && !(val_before & CCCR_INIT)) {
+ dev_err(cdev->dev,
+ "refusing to configure device when in normal mode\n");
+ return -EBUSY;
}
- /* there's a delay for module initialization */
- if (enable)
- val = CCCR_INIT | CCCR_CCE;
+ /* The chip should be in standby mode when changing the CCCR register,
+ * and some chips set the CSR and CSA bits when in standby. Furthermore,
+ * the CSR and CSA bits should be written as zeros, even when they read
+ * ones.
+ */
+ val_after &= ~(CCCR_CSR | CCCR_CSA);
- while ((m_can_read(cdev, M_CAN_CCCR) & (CCCR_INIT | CCCR_CCE)) != val) {
- if (timeout == 0) {
- netdev_warn(cdev->net, "Failed to init module\n");
- return;
- }
- timeout--;
- udelay(1);
+ while (tries--) {
+ u32 val_read;
+
+ /* Write the desired value in each try, as setting some bits in
+ * the CCCR register require other bits to be set first. E.g.
+ * setting the NISO bit requires setting the CCE bit first.
+ */
+ m_can_write(cdev, M_CAN_CCCR, val_after);
+
+ val_read = m_can_read(cdev, M_CAN_CCCR) & ~(CCCR_CSR | CCCR_CSA);
+
+ if (val_read == val_after)
+ return 0;
+
+ usleep_range(1, 5);
}
+
+ return -ETIMEDOUT;
+}
+
+static int m_can_config_enable(struct m_can_classdev *cdev)
+{
+ int err;
+
+ /* CCCR_INIT must be set in order to set CCCR_CCE, but access to
+ * configuration registers should only be enabled when in standby mode,
+ * where CCCR_INIT is always set.
+ */
+ err = m_can_cccr_update_bits(cdev, CCCR_CCE, CCCR_CCE);
+ if (err)
+ netdev_err(cdev->net, "failed to enable configuration mode\n");
+
+ return err;
+}
+
+static int m_can_config_disable(struct m_can_classdev *cdev)
+{
+ int err;
+
+ /* Only clear CCCR_CCE, since CCCR_INIT cannot be cleared while in
+ * standby mode
+ */
+ err = m_can_cccr_update_bits(cdev, CCCR_CCE, 0);
+ if (err)
+ netdev_err(cdev->net, "failed to disable configuration registers\n");
+
+ return err;
}
static void m_can_interrupt_enable(struct m_can_classdev *cdev, u32 interrupts)
@@ -1403,7 +1437,9 @@ static int m_can_chip_config(struct net_device *dev)
interrupts &= ~(IR_ARA | IR_ELO | IR_DRX | IR_TEFF | IR_TFE | IR_TCF |
IR_HPM | IR_RF1F | IR_RF1W | IR_RF1N | IR_RF0F);
- m_can_config_endisable(cdev, true);
+ err = m_can_config_enable(cdev);
+ if (err)
+ return err;
/* RX Buffer/FIFO Element Size 64 bytes data field */
m_can_write(cdev, M_CAN_RXESC,
@@ -1521,7 +1557,9 @@ static int m_can_chip_config(struct net_device *dev)
FIELD_PREP(TSCC_TCP_MASK, 0xf) |
FIELD_PREP(TSCC_TSS_MASK, TSCC_TSS_INTERNAL));
- m_can_config_endisable(cdev, false);
+ err = m_can_config_disable(cdev);
+ if (err)
+ return err;
if (cdev->ops->init)
cdev->ops->init(cdev);
@@ -1550,7 +1588,11 @@ static int m_can_start(struct net_device *dev)
cdev->tx_fifo_putidx = FIELD_GET(TXFQS_TFQPI_MASK,
m_can_read(cdev, M_CAN_TXFQS));
- return 0;
+ ret = m_can_cccr_update_bits(cdev, CCCR_INIT, 0);
+ if (ret)
+ netdev_err(dev, "failed to enter normal mode\n");
+
+ return ret;
}
static int m_can_set_mode(struct net_device *dev, enum can_mode mode)
@@ -1599,43 +1641,37 @@ static int m_can_check_core_release(struct m_can_classdev *cdev)
}
/* Selectable Non ISO support only in version 3.2.x
- * This function checks if the bit is writable.
+ * Return 1 if the bit is writable, 0 if it is not, or negative on error.
*/
-static bool m_can_niso_supported(struct m_can_classdev *cdev)
+static int m_can_niso_supported(struct m_can_classdev *cdev)
{
- u32 cccr_reg, cccr_poll = 0;
- int niso_timeout = -ETIMEDOUT;
- int i;
+ int ret, niso;
- m_can_config_endisable(cdev, true);
- cccr_reg = m_can_read(cdev, M_CAN_CCCR);
- cccr_reg |= CCCR_NISO;
- m_can_write(cdev, M_CAN_CCCR, cccr_reg);
+ ret = m_can_config_enable(cdev);
+ if (ret)
+ return ret;
- for (i = 0; i <= 10; i++) {
- cccr_poll = m_can_read(cdev, M_CAN_CCCR);
- if (cccr_poll == cccr_reg) {
- niso_timeout = 0;
- break;
- }
+ /* First try to set the NISO bit. */
+ niso = m_can_cccr_update_bits(cdev, CCCR_NISO, CCCR_NISO);
- usleep_range(1, 5);
+ /* Then clear the it again. */
+ ret = m_can_cccr_update_bits(cdev, CCCR_NISO, 0);
+ if (ret) {
+ dev_err(cdev->dev, "failed to revert the NON-ISO bit in CCCR\n");
+ return ret;
}
- /* Clear NISO */
- cccr_reg &= ~(CCCR_NISO);
- m_can_write(cdev, M_CAN_CCCR, cccr_reg);
+ ret = m_can_config_disable(cdev);
+ if (ret)
+ return ret;
- m_can_config_endisable(cdev, false);
-
- /* return false if time out (-ETIMEDOUT), else return true */
- return !niso_timeout;
+ return niso == 0;
}
static int m_can_dev_setup(struct m_can_classdev *cdev)
{
struct net_device *dev = cdev->net;
- int m_can_version, err;
+ int m_can_version, err, niso;
m_can_version = m_can_check_core_release(cdev);
/* return if unsupported version */
@@ -1684,9 +1720,11 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
cdev->can.bittiming_const = &m_can_bittiming_const_31X;
cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
- cdev->can.ctrlmode_supported |=
- (m_can_niso_supported(cdev) ?
- CAN_CTRLMODE_FD_NON_ISO : 0);
+ niso = m_can_niso_supported(cdev);
+ if (niso < 0)
+ return niso;
+ if (niso)
+ cdev->can.ctrlmode_supported |= CAN_CTRLMODE_FD_NON_ISO;
break;
default:
dev_err(cdev->dev, "Unsupported version number: %2d",
@@ -1694,21 +1732,26 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
return -EINVAL;
}
- if (cdev->ops->init)
- cdev->ops->init(cdev);
-
- return 0;
+ /* Forcing standby mode should be redundant, as the chip should be in
+ * standby after a reset. Write the INIT bit anyways, should the chip
+ * be configured by previous stage.
+ */
+ return m_can_cccr_update_bits(cdev, CCCR_INIT, CCCR_INIT);
}
static void m_can_stop(struct net_device *dev)
{
struct m_can_classdev *cdev = netdev_priv(dev);
+ int ret;
/* disable all interrupts */
m_can_disable_all_interrupts(cdev);
/* Set init mode to disengage from the network */
- m_can_config_endisable(cdev, true);
+ ret = m_can_cccr_update_bits(cdev, CCCR_INIT, CCCR_INIT);
+ if (ret)
+ netdev_err(dev, "failed to enter standby mode: %pe\n",
+ ERR_PTR(ret));
/* set the state as STOPPED */
cdev->can.state = CAN_STATE_STOPPED;
@@ -453,10 +453,17 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
goto out_power;
}
- ret = tcan4x5x_init(mcan_class);
+ tcan4x5x_check_wake(priv);
+
+ ret = tcan4x5x_write_tcan_reg(mcan_class, TCAN4X5X_INT_EN, 0);
if (ret) {
- dev_err(&spi->dev, "tcan initialization failed %pe\n",
- ERR_PTR(ret));
+ dev_err(&spi->dev, "Disabling interrupts failed %pe\n", ERR_PTR(ret));
+ goto out_power;
+ }
+
+ ret = tcan4x5x_clear_interrupts(mcan_class);
+ if (ret) {
+ dev_err(&spi->dev, "Clearing interrupts failed %pe\n", ERR_PTR(ret));
goto out_power;
}