[PATCH v2 4/4] can: flexcan: add vf610 support for FlexCAN

From: Stefan Agner
Date: Mon Jul 14 2014 - 03:49:18 EST

Extend FlexCAN driver to support Vybrid. Vybrids variant of the IP
has ECC support which is controlled through the memory error
control register (MECR). There is also an errata which leads to
false positive error detections (ID e5295). This patch disables
the memory error detection completely.

Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
---
drivers/net/can/flexcan.c | 73 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 64 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 4c598c9..a0fc53e 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -92,6 +92,27 @@
#define FLEXCAN_CTRL_ERR_ALL \
(FLEXCAN_CTRL_ERR_BUS | FLEXCAN_CTRL_ERR_STATE)

+/* FLEXCAN control register 2 (CTRL2) bits */
+#define FLEXCAN_CRL2_ECRWRE BIT(29)
+#define FLEXCAN_CRL2_WRMFRZ BIT(28)
+#define FLEXCAN_CRL2_RFFN(x) (((x) & 0x0f) << 24)
+#define FLEXCAN_CRL2_TASD(x) (((x) & 0x1f) << 19)
+#define FLEXCAN_CRL2_MRP BIT(18)
+#define FLEXCAN_CRL2_RRS BIT(17)
+#define FLEXCAN_CRL2_EACEN BIT(16)
+
+/* FLEXCAN memory error control register (MECR) bits */
+#define FLEXCAN_MECR_ECRWRDIS BIT(31)
+#define FLEXCAN_MECR_HANCEI_MSK BIT(19)
+#define FLEXCAN_MECR_FANCEI_MSK BIT(18)
+#define FLEXCAN_MECR_CEI_MSK BIT(16)
+#define FLEXCAN_MECR_HAERRIE BIT(15)
+#define FLEXCAN_MECR_FAERRIE BIT(14)
+#define FLEXCAN_MECR_EXTERRIE BIT(13)
+#define FLEXCAN_MECR_RERRDIS BIT(9)
+#define FLEXCAN_MECR_ECCDIS BIT(8)
+#define FLEXCAN_MECR_NCEFAFRZ BIT(7)
+
/* FLEXCAN error and status register (ESR) bits */
#define FLEXCAN_ESR_TWRN_INT BIT(17)
#define FLEXCAN_ESR_RWRN_INT BIT(16)
@@ -150,18 +171,20 @@
* FLEXCAN hardware feature flags
*
* Below is some version info we got:
- * SOC Version IP-Version Glitch- [TR]WRN_INT
- * Filter? connected?
- * MX25 FlexCAN2 03.00.00.00 no no
- * MX28 FlexCAN2 03.00.04.00 yes yes
- * MX35 FlexCAN2 03.00.00.00 no no
- * MX53 FlexCAN2 03.00.00.00 yes no
- * MX6s FlexCAN3 10.00.12.00 yes yes
+ * SOC Version IP-Version Glitch- [TR]WRN_INT Memory err
+ * Filter? connected? detection
+ * MX25 FlexCAN2 03.00.00.00 no no no
+ * MX28 FlexCAN2 03.00.04.00 yes yes no
+ * MX35 FlexCAN2 03.00.00.00 no no no
+ * MX53 FlexCAN2 03.00.00.00 yes no no
+ * MX6s FlexCAN3 10.00.12.00 yes yes no
+ * VF610 FlexCAN3 ? no no yes
*
* Some SOCs do not have the RX_WARN & TX_WARN interrupt line connected.
*/
#define FLEXCAN_HAS_V10_FEATURES BIT(1) /* For core version >= 10 */
#define FLEXCAN_HAS_BROKEN_ERR_STATE BIT(2) /* [TR]WRN_INT not connected */
+#define FLEXCAN_HAS_MECR_FEATURES BIT(3) /* Memory error detection */

/* Structure of the message buffer */
struct flexcan_mb {
@@ -192,8 +215,11 @@ struct flexcan_regs {
u32 crcr; /* 0x44 */
u32 rxfgmask; /* 0x48 */
u32 rxfir; /* 0x4c */
- u32 _reserved3[12];
+ u32 _reserved3[12]; /* 0x50 */
struct flexcan_mb cantxfg[64];
+ u32 _reserved4[408];
+ u32 mecr; /* 0xae0 */
+ u32 erriar; /* 0xae4 */
};

struct flexcan_devtype_data {
@@ -223,6 +249,9 @@ static struct flexcan_devtype_data fsl_imx28_devtype_data;
static struct flexcan_devtype_data fsl_imx6q_devtype_data = {
.features = FLEXCAN_HAS_V10_FEATURES,
};
+static struct flexcan_devtype_data fsl_vf610_devtype_data = {
+ .features = FLEXCAN_HAS_V10_FEATURES | FLEXCAN_HAS_MECR_FEATURES,
+};

static const struct can_bittiming_const flexcan_bittiming_const = {
.name = DRV_NAME,
@@ -807,7 +836,7 @@ static int flexcan_chip_start(struct net_device *dev)
struct flexcan_priv *priv = netdev_priv(dev);
struct flexcan_regs __iomem *regs = priv->base;
int err;
- u32 reg_mcr, reg_ctrl;
+ u32 reg_mcr, reg_ctrl, reg_crl2, reg_mecr;

/* enable module */
err = flexcan_chip_enable(priv);
@@ -884,6 +913,31 @@ static int flexcan_chip_start(struct net_device *dev)
if (priv->devtype_data->features & FLEXCAN_HAS_V10_FEATURES)
flexcan_write(0x0, &regs->rxfgmask);

+ /*
+ * On Vybrid, disable memory error detection interrupts
+ * and freeze mode.
+ * This also works around errata e5295 which generates
+ * false positive memory errors and put the device in
+ * freeze mode.
+ */
+ if (priv->devtype_data->features & FLEXCAN_HAS_MECR_FEATURES) {
+ /*
+ * Follow the protocol as described in "Detection
+ * and Correction of Memory Errors" to write to
+ * MECR register
+ */
+ reg_crl2 = flexcan_read(&regs->crl2);
+ reg_crl2 |= FLEXCAN_CRL2_ECRWRE;
+ flexcan_write(reg_crl2, &regs->crl2);
+
+ reg_mecr = flexcan_read(&regs->mecr);
+ reg_mecr &= ~FLEXCAN_MECR_ECRWRDIS;
+ flexcan_write(reg_mecr, &regs->mecr);
+ reg_mecr &= ~(FLEXCAN_MECR_NCEFAFRZ | FLEXCAN_MECR_HANCEI_MSK |
+ FLEXCAN_MECR_FANCEI_MSK);
+ flexcan_write(reg_mecr, &regs->mecr);
+ }
+
err = flexcan_transceiver_enable(priv);
if (err)
goto out_chip_disable;
@@ -1094,6 +1148,7 @@ static const struct of_device_id flexcan_of_match[] = {
{ .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
{ .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data, },
{ .compatible = "fsl,p1010-flexcan", .data = &fsl_p1010_devtype_data, },
+ { .compatible = "fsl,vf610-flexcan", .data = &fsl_vf610_devtype_data, },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, flexcan_of_match);
--
2.0.1

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