Re: [PATCH 3/3] drivers/net/ethoc: add mdio bus support

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, May 13, 2014 at 08:38:26PM +0200, Franck Jullien wrote:
> Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
> ---
>  drivers/net/Kconfig |    1 +
>  drivers/net/ethoc.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
> index 057abd2..7a0d5e1 100644
> --- a/drivers/net/Kconfig
> +++ b/drivers/net/Kconfig
> @@ -80,6 +80,7 @@ config DRIVER_NET_EP93XX
>  
>  config DRIVER_NET_ETHOC
>  	bool "OpenCores ethernet MAC driver"
> +	select PHYLIB
>  	help
>  	  This option enables support for the OpenCores 10/100 Mbps
>  	  Ethernet MAC core.
> diff --git a/drivers/net/ethoc.c b/drivers/net/ethoc.c
> index b000875..42780be 100644
> --- a/drivers/net/ethoc.c
> +++ b/drivers/net/ethoc.c
> @@ -178,6 +178,8 @@ struct ethoc {
>  
>  	u32 num_rx;
>  	u32 cur_rx;
> +
> +	struct mii_bus *miibus;
>  };
>  
>  /**
> @@ -481,18 +483,71 @@ static int ethoc_send_packet(struct eth_device *edev, void *packet, int length)
>  	return 0;
>  }
>  
> +static int ethoc_mdio_read(struct mii_bus *bus, int phy, int reg)
> +{
> +	struct ethoc *priv = bus->priv;
> +	int i;
> +
> +	ethoc_write(priv, MIIADDRESS, MIIADDRESS_ADDR(phy, reg));
> +	ethoc_write(priv, MIICOMMAND, MIICOMMAND_READ);
> +
> +	for (i = 0; i < 5; i++) {
> +		u32 status = ethoc_read(priv, MIISTATUS);
> +		if (!(status & MIISTATUS_BUSY)) {
> +			u32 data = ethoc_read(priv, MIIRX_DATA);
> +			/* reset MII command register */
> +			ethoc_write(priv, MIICOMMAND, 0);
> +			return data;
> +		}
> +		mdelay(1);
> +	}

We are polling in barebox anyway. Doing it like above means you have a
1ms window in which you do not return even if your hardware is ready.
Please use a timeout loop:

	uint64_t start = get_time_ns();

	while (!is_timeout(start, 5 * MSECOND)) {
		u32 status = ethoc_read(priv, MIISTATUS);
		if (!(status & MIISTATUS_BUSY)) {
			u32 data = ethoc_read(priv, MIIRX_DATA);
			/* reset MII command register */
			ethoc_write(priv, MIICOMMAND, 0);
			return data;
		}
	}

	return -EBUSY;

>  
>  	edev = xzalloc(sizeof(struct eth_device) +
>  		       sizeof(struct ethoc));
>  	edev->priv = (struct ethoc *)(edev + 1);
> +	miibus = xzalloc(sizeof(struct mii_bus));

No need for a separate allocation. Just embed this into struct ethoc.

Sascha

-- 
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