Patchwork asus m2v: Set DDR2 voltage to 1.8V

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Submitter Tobias Diedrich
Date 2010-11-12 20:42:52
Message ID <20101112204252.GD17514@yumi.tdiedrich.de>
Download mbox | patch
Permalink /patch/2310/
State Accepted
Headers show

Comments

Tobias Diedrich - 2010-11-12 20:42:52
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 <ranma+coreboot@tdiedrich.de>

---
Peter Stuge - 2010-11-12 20:46:17
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 <ranma+coreboot@tdiedrich.de>

Acked-by: Peter Stuge <peter@stuge.se>

r6066
Myles Watson - 2010-11-12 20:46:22
On Fri, Nov 12, 2010 at 1:42 PM, Tobias Diedrich
<ranma+coreboot@tdiedrich.de> 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 <ranma+coreboot@tdiedrich.de>
>
> ---
>
> 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 <mylesgw@gmail.com>

Thanks,
Myles
Tobias Diedrich - 2010-11-13 01:47:09
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 <mylesgw@gmail.com>

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.

Patch

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)