Patch set updated for coreboot: [WIP]nb/intel/sandybridge/raminit: Add 100Mhz refclock support

[Patrick Rudolph]

Patrick Rudolph ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17607

-gerrit

commit ed0744b3cee41e5f6da77f799e7a16fdf54430a9
Author: Patrick Rudolph 
Date:   Thu Nov 24 19:40:23 2016 +0100

[WIP]nb/intel/sandybridge/raminit: Add 100Mhz refclock support

Add support for 100Mhz reference clock on ivybridge.
    Allows to use more frequencies than sandybridge.

UNTESTED!

Change-Id: I780d34ded2c1e3737ae1af685c8c2da832842e7c
    Signed-off-by: Patrick Rudolph 
---
 src/northbridge/intel/sandybridge/raminit_ivy.c | 43 +++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/src/northbridge/intel/sandybridge/raminit_ivy.c b/src/northbridge/intel/sandybridge/raminit_ivy.c
index fd45014..f432362 100644
--- a/src/northbridge/intel/sandybridge/raminit_ivy.c
+++ b/src/northbridge/intel/sandybridge/raminit_ivy.c
@@ -19,6 +19,8 @@
 #include <console/usb.h>
 #include <cpu/x86/msr.h>
 #include <delay.h>
+#include <arch/io.h>
+#include <device/pci_ops.h>
 #include "raminit_native.h"
 #include "raminit_common.h"

@@ -429,14 +431,20 @@ static void dram_timing(ramctr_timing * ctrl)

static void dram_freq(ramctr_timing * ctrl)
 {
+	bool ref_100mhz_support;
+	u32 reg32;
+
    if (ctrl->tCK > TCK_400MHZ) {
    	printk (BIOS_ERR, "DRAM frequency is under lowest supported "
    			"frequency (400 MHz). Increasing to 400 MHz as last resort");
    	ctrl->tCK = TCK_400MHZ;
    }

-	/* TODO: implement 100Mhz refclock */
-	ctrl->base_freq = 133;
+	/* 100 Mhz reference clock supported */
+	reg32 = pci_read_config32(PCI_DEV(0, 0, 0), CAPID0_B);
+	ref_100mhz_support = !!((reg32 >> 21) & 0x7);
+	printk(BIOS_DEBUG, "100Mhz reference clock support: %u\n",
+		   ref_100mhz_support);

while (1) {
    	u8 val2;
@@ -444,22 +452,49 @@ static void dram_freq(ramctr_timing * ctrl)

/* Step 1 - Set target PCU frequency */

-		if (ctrl->tCK <= TCK_1066MHZ) {
+		if (ctrl->tCK <= TCK_1200MHZ) {
+			ctrl->tCK = TCK_1200MHZ;
+			ctrl->base_freq = 100;
+		} else if (ctrl->tCK <= TCK_1100MHZ) {
+			ctrl->tCK = TCK_1100MHZ;
+			ctrl->base_freq = 100;
+		} else if (ctrl->tCK <= TCK_1066MHZ) {
    		ctrl->tCK = TCK_1066MHZ;
+			ctrl->base_freq = 133;
+		} else if (ctrl->tCK <= TCK_1000MHZ) {
+			ctrl->tCK = TCK_1000MHZ;
+			ctrl->base_freq = 100;
    	} else if (ctrl->tCK <= TCK_933MHZ) {
    		ctrl->tCK = TCK_933MHZ;
+			ctrl->base_freq = 133;
+		} else if (ctrl->tCK <= TCK_900MHZ) {
+			ctrl->tCK = TCK_900MHZ;
+			ctrl->base_freq = 100;
    	} else if (ctrl->tCK <= TCK_800MHZ) {
    		ctrl->tCK = TCK_800MHZ;
+			ctrl->base_freq = 133;
+		} else if (ctrl->tCK <= TCK_700MHZ) {
+			ctrl->tCK = TCK_700MHZ;
+			ctrl->base_freq = 100;
    	} else if (ctrl->tCK <= TCK_666MHZ) {
    		ctrl->tCK = TCK_666MHZ;
+			ctrl->base_freq = 133;
    	} else if (ctrl->tCK <= TCK_533MHZ) {
    		ctrl->tCK = TCK_533MHZ;
+			ctrl->base_freq = 133;
    	} else if (ctrl->tCK <= TCK_400MHZ) {
    		ctrl->tCK = TCK_400MHZ;
+			ctrl->base_freq = 133;
    	} else {
    		die ("No lock frequency found");
    	}

+		if (!ref_100mhz_support && ctrl->base_freq == 100) {
+			/* Skip unsupported frequency. */
+			ctrl->tCK++;
+			continue;
+		}
+
    	/* Frequency multiplier.  */
    	u32 FRQ = get_FRQ(ctrl->tCK, ctrl->base_freq);

@@ -473,6 +508,8 @@ static void dram_freq(ramctr_timing * ctrl)

/* Step 2 - Select frequency in the MCU */
    	reg1 = FRQ;
+		if (ctrl->base_freq == 100)
+			reg1 |= 0x100; /* Enable 100Mhz REF clock */
    	reg1 |= 0x80000000;	// set running bit
    	MCHBAR32(MC_BIOS_REQ) = reg1;
    	int i=0;