Re: [PATCH 2/2] ibm_newemac: PowerPC 440EP/440GR EMAC PHY clock workaround

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Thu, 2008-03-06 at 16:43 +0300, Valentine Barshak wrote:
> This patch adds ibm_newemac PHY clock workaround for 440EP/440GR EMAC
> attached to a PHY which doesn't generate RX clock if there is no link.
> The code is based on the previous ibm_emac driver stuff. The 440EP/440GR
> allows controlling each EMAC clock separately as opposed to global clock
> selection for 440GX.
> 
> Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> ---
>  drivers/net/ibm_newemac/core.c |   34 ++++++++++++++++++++++++++++++++--
>  drivers/net/ibm_newemac/core.h |    6 +++++-
>  2 files changed, 37 insertions(+), 3 deletions(-)
> 
> diff -pruN linux-2.6.orig/drivers/net/ibm_newemac/core.c linux-2.6/drivers/net/ibm_newemac/core.c
> --- linux-2.6.orig/drivers/net/ibm_newemac/core.c	2008-02-26 16:32:33.000000000 +0300
> +++ linux-2.6/drivers/net/ibm_newemac/core.c	2008-02-26 16:37:52.000000000 +0300
> @@ -129,10 +129,29 @@ static struct device_node *emac_boot_lis
>  static inline void emac_report_timeout_error(struct emac_instance *dev,
>  					     const char *error)
>  {
> -	if (net_ratelimit())
> +	if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX |
> +				  EMAC_FTR_440EP_PHY_CLK_FIX))
> +		DBG(dev, "%s" NL, error);
> +	else if (net_ratelimit())
>  		printk(KERN_ERR "%s: %s\n", dev->ndev->name, error);
>  }
>  
> +/* EMAC PHY clock workaround:
> + * 440EP/440GR has more sane SDR0_MFR register implementation than 440GX,
> + * which allows controlling each EMAC clock
> + */
> +static inline void emac_rx_clk_tx(struct emac_instance *dev)
> +{
> +	if (emac_has_feature(dev, EMAC_FTR_440EP_PHY_CLK_FIX))
> +		dcri_clrset(SDR0, SDR0_MFR, 0, SDR0_MFR_ECS >> dev->cell_index);
> +}
> +
> +static inline void emac_rx_clk_default(struct emac_instance *dev)
> +{
> +	if (emac_has_feature(dev, EMAC_FTR_440EP_PHY_CLK_FIX))
> +		dcri_clrset(SDR0, SDR0_MFR, SDR0_MFR_ECS >> dev->cell_index, 0);
> +}
> +
>  /* PHY polling intervals */
>  #define PHY_POLL_LINK_ON	HZ
>  #define PHY_POLL_LINK_OFF	(HZ / 5)
> @@ -1089,9 +1112,11 @@ static int emac_open(struct net_device *
>  		int link_poll_interval;
>  		if (dev->phy.def->ops->poll_link(&dev->phy)) {
>  			dev->phy.def->ops->read_link(&dev->phy);
> +			emac_rx_clk_default(dev);
>  			netif_carrier_on(dev->ndev);
>  			link_poll_interval = PHY_POLL_LINK_ON;
>  		} else {
> +			emac_rx_clk_tx(dev);
>  			netif_carrier_off(dev->ndev);
>  			link_poll_interval = PHY_POLL_LINK_OFF;
>  		}
> @@ -1169,6 +1194,7 @@ static void emac_link_timer(struct work_
>  
>  	if (dev->phy.def->ops->poll_link(&dev->phy)) {
>  		if (!netif_carrier_ok(dev->ndev)) {
> +			emac_rx_clk_default(dev);
>  			/* Get new link parameters */
>  			dev->phy.def->ops->read_link(&dev->phy);
>  
> @@ -1181,6 +1207,7 @@ static void emac_link_timer(struct work_
>  		link_poll_interval = PHY_POLL_LINK_ON;
>  	} else {
>  		if (netif_carrier_ok(dev->ndev)) {
> +			emac_rx_clk_tx(dev);
>  			netif_carrier_off(dev->ndev);
>  			netif_tx_disable(dev->ndev);
>  			emac_reinitialize(dev);
> @@ -2325,9 +2352,12 @@ static int __devinit emac_init_phy(struc
>  	dev->phy.mdio_read = emac_mdio_read;
>  	dev->phy.mdio_write = emac_mdio_write;
>  
> -	/* Enable internal clock source */
> +	/* EMAC PHY clock workaround */
>  	if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX))
> +		/* Enable internal clock source */
>  		dcri_clrset(SDR0, SDR0_MFR, 0, SDR0_MFR_ECS);
> +	else
> +		emac_rx_clk_tx(dev);
>  
>  	/* Configure EMAC with defaults so we can at least use MDIO
>  	 * This is needed mostly for 440GX
> @@ -2495,6 +2525,10 @@ static int __devinit emac_init_config(st
>  		dev->features |= EMAC_FTR_EMAC4;
>  		if (of_device_is_compatible(np, "ibm,emac-440gx"))
>  			dev->features |= EMAC_FTR_440GX_PHY_CLK_FIX;
> +	} else {
> +		if (of_device_is_compatible(np, "ibm,emac-440ep") ||
> +		    of_device_is_compatible(np, "ibm,emac-440gr"))
> +			dev->features |= EMAC_FTR_440EP_PHY_CLK_FIX;
>  	}
>  
>  	/* Fixup some feature bits based on the device tree */
> diff -pruN linux-2.6.orig/drivers/net/ibm_newemac/core.h linux-2.6/drivers/net/ibm_newemac/core.h
> --- linux-2.6.orig/drivers/net/ibm_newemac/core.h	2008-02-26 16:32:33.000000000 +0300
> +++ linux-2.6/drivers/net/ibm_newemac/core.h	2008-02-26 16:37:52.000000000 +0300
> @@ -305,6 +305,10 @@ struct emac_instance {
>   * Set if we need phy clock workaround for 440gx
>   */
>  #define EMAC_FTR_440GX_PHY_CLK_FIX	0x00000080
> +/*
> + * Set if we need phy clock workaround for 440ep or 440gr
> + */
> +#define EMAC_FTR_440EP_PHY_CLK_FIX	0x00000100
>  
> 
>  /* Right now, we don't quite handle the always/possible masks on the
> @@ -328,7 +332,7 @@ enum {
>  #ifdef CONFIG_IBM_NEW_EMAC_RGMII
>  	    EMAC_FTR_HAS_RGMII	|
>  #endif
> -	    0,
> +	EMAC_FTR_440EP_PHY_CLK_FIX,
>  };
>  
>  static inline int emac_has_feature(struct emac_instance *dev,