From 64df52e269d5ec2c04bd7b65381b21d6966326af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ky=C3=B6sti=20M=C3=A4lkki?= <kyosti.malkki@gmail.com>
Date: Fri, 1 Sep 2017 06:13:08 +0300
Subject: AGESA f14: Work around soft-resets
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Vendorcode expects some DRAM controller registers to
be writable, but they are actually locked after soft
resets if C6 states are enabled.

Without the workaround, raminit fails on soft resets.

Change-Id: I6b9e275e11b2907d026c13341334983a4d9c8889
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/21317
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
---
 src/northbridge/amd/agesa/family14/state_machine.c | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'src/northbridge/amd')

diff --git a/src/northbridge/amd/agesa/family14/state_machine.c b/src/northbridge/amd/agesa/family14/state_machine.c
index 81d15bc445..025d94fffd 100644
--- a/src/northbridge/amd/agesa/family14/state_machine.c
+++ b/src/northbridge/amd/agesa/family14/state_machine.c
@@ -16,7 +16,13 @@
 #include "Porting.h"
 #include "AGESA.h"
 
+#include <arch/io.h>
 #include <cbmem.h>
+#include <device/device.h>
+#include <device/pci_def.h>
+#include <halt.h>
+#include <reset.h>
+#include <smp/node.h>
 #include <northbridge/amd/agesa/state_machine.h>
 #include <northbridge/amd/agesa/agesa_helper.h>
 
@@ -24,6 +30,24 @@
 
 void platform_BeforeInitReset(struct sysinfo *cb, AMD_RESET_PARAMS *Reset)
 {
+	/* Reboots with outb(3,0x92), outb(4,0xcf9) or triple-fault all
+	 * would fail later in AmdInitPost(), when DRAM is already configured
+	 * and C6DramLock bit has been set.
+	 *
+	 * As a workaround, do a hard reset to clear C6DramLock bit.
+	 */
+#ifdef __SIMPLE_DEVICE__
+	pci_devfn_t dev = PCI_DEV(0, 0x18, 2);
+#else
+	struct device *dev = dev_find_slot(0, PCI_DEVFN(0x18, 2));
+#endif
+	if (boot_cpu()) {
+		u32 mct_cfg_lo = pci_read_config32(dev, 0x118);
+		if (mct_cfg_lo & (1<<19)) {
+			printk(BIOS_CRIT, "C6DramLock is set, resetting\n");
+			hard_reset();
+		}
+	}
 }
 
 void platform_BeforeInitEarly(struct sysinfo *cb, AMD_EARLY_PARAMS *Early)
-- 
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