Re: [PATCH 1/2] ibm_newemac: PowerPC 440GX EMAC PHY clock workaround

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

On Thu, 2008-03-06 at 16:41 +0300, Valentine Barshak wrote:
> The PowerPC 440GX Taishan board fails to reset EMAC3 (reset timeout error)
> if there's no link. Because of that it fails to find PHY chip. The older ibm_emac
> driver had a workaround for that: the EMAC_CLK_INTERNAL/EMAC_CLK_EXTERNAL macros,
> which toggle the Ethernet Clock Select bit in the SDR0_MFR register. This patch
> does the same for "ibm,emac-440gx" compatible chips. The workaround forces
> clock on -all- EMACs, so we select clock under global emac_phy_map_lock.
> 
> Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>

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

Just get them acked by Jeff now and they can go in via Josh tree.

Cheers,
Ben.

> ---
>  drivers/net/ibm_newemac/core.c |   16 +++++++++++++++-
>  drivers/net/ibm_newemac/core.h |    8 ++++++--
>  2 files changed, 21 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	2008-02-22 19:56:26.000000000 +0300
> +++ linux-2.6/drivers/net/ibm_newemac/core.c	2008-02-22 20:38:47.000000000 +0300
> @@ -43,6 +43,8 @@
>  #include <asm/io.h>
>  #include <asm/dma.h>
>  #include <asm/uaccess.h>
> +#include <asm/dcr.h>
> +#include <asm/dcr-regs.h>
>  
>  #include "core.h"
>  
> @@ -2323,6 +2325,10 @@ 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 */
> +	if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX))
> +		dcri_clrset(SDR0, SDR0_MFR, 0, SDR0_MFR_ECS);
> +
>  	/* Configure EMAC with defaults so we can at least use MDIO
>  	 * This is needed mostly for 440GX
>  	 */
> @@ -2355,6 +2361,11 @@ static int __devinit emac_init_phy(struc
>  			if (!emac_mii_phy_probe(&dev->phy, i))
>  				break;
>  		}
> +
> +	/* Enable external clock source */
> +	if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX))
> +		dcri_clrset(SDR0, SDR0_MFR, SDR0_MFR_ECS, 0);
> +
>  	mutex_unlock(&emac_phy_map_lock);
>  	if (i == 0x20) {
>  		printk(KERN_WARNING "%s: can't find PHY!\n", np->full_name);
> @@ -2480,8 +2491,11 @@ static int __devinit emac_init_config(st
>  	}
>  
>  	/* Check EMAC version */
> -	if (of_device_is_compatible(np, "ibm,emac4"))
> +	if (of_device_is_compatible(np, "ibm,emac4")) {
>  		dev->features |= EMAC_FTR_EMAC4;
> +		if (of_device_is_compatible(np, "ibm,emac-440gx"))
> +			dev->features |= EMAC_FTR_440GX_PHY_CLK_FIX;
> +	}
>  
>  	/* Fixup some feature bits based on the device tree */
>  	if (of_get_property(np, "has-inverted-stacr-oc", NULL))
> 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	2008-02-21 16:45:36.000000000 +0300
> +++ linux-2.6/drivers/net/ibm_newemac/core.h	2008-02-22 19:57:44.000000000 +0300
> @@ -301,6 +301,10 @@ struct emac_instance {
>   * Set if we have new type STACR with STAOPC
>   */
>  #define EMAC_FTR_HAS_NEW_STACR		0x00000040
> +/*
> + * Set if we need phy clock workaround for 440gx
> + */
> +#define EMAC_FTR_440GX_PHY_CLK_FIX	0x00000080
>  
> 
>  /* Right now, we don't quite handle the always/possible masks on the
> @@ -312,8 +316,8 @@ enum {
>  
>  	EMAC_FTRS_POSSIBLE	=
>  #ifdef CONFIG_IBM_NEW_EMAC_EMAC4
> -	    EMAC_FTR_EMAC4	| EMAC_FTR_HAS_NEW_STACR	|
> -	    EMAC_FTR_STACR_OC_INVERT	|
> +	    EMAC_FTR_EMAC4 | EMAC_FTR_HAS_NEW_STACR |
> +	    EMAC_FTR_STACR_OC_INVERT | EMAC_FTR_440GX_PHY_CLK_FIX |
>  #endif
>  #ifdef CONFIG_IBM_NEW_EMAC_TAH
>  	    EMAC_FTR_HAS_TAH	|