Re: [PATCH 1/3] can: c_can: Add d_can raminit support

[Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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On 11/14/2012 07:08 PM, AnilKumar Ch wrote:
> Add D_CAN raminit support to C_CAN driver to enable D_CAN RAM,
> which holds all the message objects during transmission or
> receiving of data. This initialization/de-initialization should
> be done in synchronous with D_CAN clock.
> 
> In case of AM335X-EVM (active user of D_CAN driver) message RAM is
> controlled through control module register for both instances. So
> control module register details is required to initialization or
> de-initialization of message RAM according to instance number.
> 
> Control module memory resource is obtained from D_CAN dt node and
> instance number obtained from device tree aliases node.
> 
> Signed-off-by: AnilKumar Ch <anilkumar-l0cyMroinI0@public.gmane.org>

Some nitpicks inline.

Marc

> ---
>  drivers/net/can/c_can/c_can.c          |   12 +++++++++++
>  drivers/net/can/c_can/c_can.h          |    3 +++
>  drivers/net/can/c_can/c_can_platform.c |   34 +++++++++++++++++++++++++++++++-
>  3 files changed, 48 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
> index e5180df..c15830c 100644
> --- a/drivers/net/can/c_can/c_can.c
> +++ b/drivers/net/can/c_can/c_can.c
> @@ -233,6 +233,12 @@ static inline void c_can_pm_runtime_put_sync(const struct c_can_priv *priv)
>  		pm_runtime_put_sync(priv->device);
>  }
>  
> +static inline void c_can_reset_ram(const struct c_can_priv *priv, bool enable)
> +{
> +	if (priv->ram_init)
> +		priv->ram_init(priv, enable);
> +}
> +
>  static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
>  {
>  	return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +
> @@ -1090,6 +1096,7 @@ static int c_can_open(struct net_device *dev)
>  	struct c_can_priv *priv = netdev_priv(dev);
>  
>  	c_can_pm_runtime_get_sync(priv);
> +	c_can_reset_ram(priv, true);
>  
>  	/* open the can device */
>  	err = open_candev(dev);
> @@ -1118,6 +1125,7 @@ static int c_can_open(struct net_device *dev)
>  exit_irq_fail:
>  	close_candev(dev);
>  exit_open_fail:
> +	c_can_reset_ram(priv, false);
>  	c_can_pm_runtime_put_sync(priv);
>  	return err;
>  }
> @@ -1131,6 +1139,8 @@ static int c_can_close(struct net_device *dev)
>  	c_can_stop(dev);
>  	free_irq(dev->irq, dev);
>  	close_candev(dev);
> +
> +	c_can_reset_ram(priv, false);
>  	c_can_pm_runtime_put_sync(priv);
>  
>  	return 0;
> @@ -1188,6 +1198,7 @@ int c_can_power_down(struct net_device *dev)
>  
>  	c_can_stop(dev);
>  
> +	c_can_reset_ram(priv, false);
>  	c_can_pm_runtime_put_sync(priv);
>  
>  	return 0;
> @@ -1206,6 +1217,7 @@ int c_can_power_up(struct net_device *dev)
>  	WARN_ON(priv->type != BOSCH_D_CAN);
>  
>  	c_can_pm_runtime_get_sync(priv);
> +	c_can_reset_ram(priv, true);
>  
>  	/* Clear PDR and INIT bits */
>  	val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
> diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
> index e5ed41d..419de5c 100644
> --- a/drivers/net/can/c_can/c_can.h
> +++ b/drivers/net/can/c_can/c_can.h
> @@ -169,6 +169,9 @@ struct c_can_priv {
>  	void *priv;		/* for board-specific data */
>  	u16 irqstatus;
>  	enum c_can_dev_id type;
> +	u32 __iomem *raminit_ctrlreg;
> +	unsigned int instance;
> +	void (*ram_init) (const struct c_can_priv *priv, bool enable);
>  };
>  
>  struct net_device *alloc_c_can_dev(void);
> diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
> index ee141613..2e61d69 100644
> --- a/drivers/net/can/c_can/c_can_platform.c
> +++ b/drivers/net/can/c_can/c_can_platform.c
> @@ -38,6 +38,8 @@
>  
>  #include "c_can.h"
>  
> +#define CAN_RAMINIT_START_MASK(i)	(1 << (i))
> +
>  /*
>   * 16-bit c_can registers can be arranged differently in the memory
>   * architecture of different implementations. For example: 16-bit
> @@ -68,6 +70,24 @@ static void c_can_plat_write_reg_aligned_to_32bit(struct c_can_priv *priv,
>  	writew(val, priv->base + 2 * priv->regs[index]);
>  }
>  
> +static void c_can_hw_raminit(const struct c_can_priv *priv, bool enable)
> +{
> +	u32 val;
> +
> +	if (!priv->raminit_ctrlreg || (priv->instance < 0))
> +		return;

Can you move this sanity check to the probe function and only assign
priv->ram_init if the above is true?

> +
> +	val = readl(priv->raminit_ctrlreg);
> +	if (enable) {
> +		val &= ~CAN_RAMINIT_START_MASK(priv->instance);
> +		val |= CAN_RAMINIT_START_MASK(priv->instance);
> +		writel(val, priv->raminit_ctrlreg);
> +	} else {
> +		val &= ~CAN_RAMINIT_START_MASK(priv->instance);
> +		writel(val, priv->raminit_ctrlreg);
> +	}
> +}
> +
>  static struct platform_device_id c_can_id_table[] = {
>  	[BOSCH_C_CAN_PLATFORM] = {
>  		.name = KBUILD_MODNAME,
> @@ -99,7 +119,7 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
>  	const struct of_device_id *match;
>  	const struct platform_device_id *id;
>  	struct pinctrl *pinctrl;
> -	struct resource *mem;
> +	struct resource *mem, *res;
>  	int irq;
>  	struct clk *clk;
>  
> @@ -178,6 +198,18 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
>  		priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
>  		priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
>  		priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
> +
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +		priv->raminit_ctrlreg =
> +				devm_request_and_ioremap(&pdev->dev, res);

What happens if there isn't a second IORESOURCE_MEM region? devm_request
will print an error in this case and any other error, too [1]. Do we
need streamlining here?

[1] http://lxr.free-electrons.com/source/drivers/base/platform.c#L59

> +		if (!priv->raminit_ctrlreg)
> +			dev_warn(&pdev->dev, "failed to obtain control memory\n");
> +
> +		if (pdev->dev.of_node)
> +			pdev->id = of_alias_get_id(pdev->dev.of_node, "d_can");
> +
> +		priv->instance = pdev->id;

Please do not modify the pdev, better you use something like this:

    pdev->id < 0 ? of_alias_get_id(pdev->dev.of_node, "d_can") :
        pdev->id;

> +		priv->ram_init = c_can_hw_raminit;
>  		break;
>  	default:
>  		ret = -EINVAL;
> 

Marc
-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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