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

[Philippe De Muyter]

On Wed, Feb 19, 2014 at 12:19:04PM -0700, Troy Kisky wrote:
> 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 at 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);
> }

Yeah.  I had not thought about it.  Thanks.
Actually, one could also call directly get_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,
> > 

-- 
Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140 Bruxelles