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

From: Marc Kleine-Budde
Date: Mon Jul 14 2014 - 08:14:35 EST

On 07/14/2014 09:48 AM, Stefan Agner wrote:
> 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>

Looks good, small nitpick inline.

> ---
> 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
> + */


One nitpick regarding the comment. In driver/net, the preferred
multi-line comment style is

/* comment starts here
* comment continues
*/

> + 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);
>

Marc

--
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