[patch] asus m2v: Set DDR2 voltage to 1.8V

[Tobias Diedrich]

Set DDR2 voltage to 1.8V

The power-on default is 1.95V, set the DDR2 voltage to
standards-conforming 1.8V.

I also measured with a multimeter to confirm this.

Signed-off-by: Tobias Diedrich

---

Index: src/mainboard/asus/m2v/romstage.c
===================================================================
--- src/mainboard/asus/m2v/romstage.c.orig	2010-11-12 21:35:25.000000000 +0100
+++ src/mainboard/asus/m2v/romstage.c	2010-11-12 21:35:42.000000000 +0100
@@ -194,6 +194,19 @@
    	giv++;
    }
    it8712f_exit_conf();
+
+	printk(BIOS_INFO, "it8712f gpio: Setting DDR2 voltage to 1.80V\n");
+	/*
+	 * upper two bits of gpio_base+4 control ddr2 voltage:
+	 * 11: 1.80V
+	 * 01: 1.85V
+	 * 10: 1.90V
+	 * 00: 1.95V
+	 *
+	 * The lower six bits are inputs and normally read back as 1
+	 * (except bit 2, which seems rather random).
+	 */
+	outb(0xff, IT8712F_GPIO_BASE+4);
 }

static void m2v_bus_init(void)

[Peter Stuge]

Tobias Diedrich wrote:
> Set DDR2 voltage to 1.8V
>
> The power-on default is 1.95V, set the DDR2 voltage to
> standards-conforming 1.8V.
>
> I also measured with a multimeter to confirm this.
>
> Signed-off-by: Tobias Diedrich

Acked-by: Peter Stuge

r6066

[Myles Watson]

On Fri, Nov 12, 2010 at 1:42 PM, Tobias Diedrich
 wrote:
> Set DDR2 voltage to 1.8V
>
> The power-on default is 1.95V, set the DDR2 voltage to
> standards-conforming 1.8V.
>
> I also measured with a multimeter to confirm this.
>
> Signed-off-by: Tobias Diedrich
> Index: src/mainboard/asus/m2v/romstage.c
>
> --- src/mainboard/asus/m2v/romstage.c.orig      2010-11-12 21:35:25.000000000 +0100
> +++ src/mainboard/asus/m2v/romstage.c   2010-11-12 21:35:42.000000000 +0100
> @@ -194,6 +194,19 @@
>                giv++;
>        }
>        it8712f_exit_conf();
> printk(BIOS_INFO, "it8712f gpio: Setting DDR2 voltage to 1.80V\n");

Maybe this should be BIOS_SPEW.  If it's the standard, I don't think
it needs to be seen every boot.

Acked-by: Myles Watson

Thanks,
Myles

[Tobias Diedrich]

Myles Watson wrote:
> > Index: src/mainboard/asus/m2v/romstage.c
> >
> > --- src/mainboard/asus/m2v/romstage.c.orig      2010-11-12 21:35:25.000000000 +0100
> > +++ src/mainboard/asus/m2v/romstage.c   2010-11-12 21:35:42.000000000 +0100
> > @@ -194,6 +194,19 @@
> >                giv++;
> >        }
> >        it8712f_exit_conf();
> > printk(BIOS_INFO, "it8712f gpio: Setting DDR2 voltage to 1.80V\n");
>
> Maybe this should be BIOS_SPEW.  If it's the standard, I don't think
> it needs to be seen every boot.
>
> Acked-by: Myles Watson

I think BIOS_SPEW would be ok too.
I just wanted to leave in a debug message, so if someone wanted to
change the voltage he can grep for it.