[U-Boot] [PATCH] net: fec_mxc: fix mii_speed configuration for MX6's

[Troy Kisky <troy.kisky@boundarydevices.com>]

On 2/19/2014 7:27 AM, Philippe De Muyter wrote:
> On MX6DL at least, measured mdc speed was wrong (3.3 Mhz instead of 2.5
> Mhz), because of wrong assumptions about the reference clock and the
> way the divider is used.
> 
> I have fixed that for all MX6's by using the IPG clock as the reference
> clock, and applying the - 1 correction when we have a ENET MAC instead
> of a FEC MAC, just like what is done in the fec linux driver.
> 
> Signed-off-by: Philippe De Muyter <phdm@macqel.be>
> ---
>  drivers/net/fec_mxc.c |   20 +++++++++++++++++---
>  1 files changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/fec_mxc.c b/drivers/net/fec_mxc.c
> index 3b2b995..3ab0ecd 100644
> --- a/drivers/net/fec_mxc.c
> +++ b/drivers/net/fec_mxc.c
> @@ -124,13 +124,27 @@ static int fec_mdio_read(struct ethernet_regs *eth, uint8_t phyAddr,
>  
>  static void fec_mii_setspeed(struct ethernet_regs *eth)
>  {
> +	u32 sysclock;
> +	u32 mii_speed;
> +
>  	/*
>  	 * Set MII_SPEED = (1/(mii_speed * 2)) * System Clock
>  	 * and do not drop the Preamble.
> +	 * shift the result by 1, because MII_SPEED field is at bits 6..1.
>  	 */
> -	writel((((imx_get_fecclk() / 1000000) + 2) / 5) << 1,
> -			&eth->mii_speed);
> -	debug("%s: mii_speed %08x\n", __func__, readl(&eth->mii_speed));
> +#if defined(CONFIG_MX6)
> +	sysclock = mxc_get_clock(MXC_IPG_CLK);
> +#else
> +	sysclock = imx_get_fecclk();
> +#endif


Why not fix it in arch/arm/cpu/armv7/mx6/clock.c ?

u32 imx_get_fecclk(void)
{
-	return decode_pll(PLL_ENET, MXC_HCLK);
+	mxc_get_clock(MXC_IPG_CLK);
}

> +#define MIIM_SPEED 2500000
> +	mii_speed = DIV_ROUND_UP(sysclock, (MIIM_SPEED * 2));
> +#ifdef FEC_QUIRK_ENET_MAC
> +	mii_speed -= 1;
> +#endif
> +	writel(mii_speed << 1, &eth->mii_speed);
> +	debug("%s: sysclock %u, mii_speed %08x\n", __func__, sysclock,
> +						readl(&eth->mii_speed));
>  }
>  
>  static int fec_mdio_write(struct ethernet_regs *eth, uint8_t phyAddr,
>