coreboot/dell: move e6400 to new tree, dell

the ddr2 fix broke *ddr3* on gm45 thinkpads in
testing, depending on memory modules. this was
established by removing patches, re-doing
configs etc, on a user's X200 (testing gentoo
and freebsd). the X200 kept randomly rebooting
or having random glitches.

the configs themselves (gm45 thinkpads) will
also be re-done, because i found minor issues
unrelated, but this patch moves dell e6400 to
its own tree. the ddr2 fix is no longer present
in coreboot/default, only coreboot/dell.

i noticed minor differences in gm45 thinkpad
configs, when re-doing the configs, versus
what are currently in lbmk master; for instance,
vbt was not enabled anymore, on thinkpad x200.
modifications to these will be done separately.

Signed-off-by: Leah Rowe <leah@libreboot.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/config/coreboot/dell/patches/0016-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch b/config/coreboot/dell/patches/0016-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch
new file mode 100644
index 00000000..0f9b192d
--- /dev/null
+++ b/config/coreboot/dell/patches/0016-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch
@@ -0,0 +1,47 @@
+From 3ec06fa2393995b87af1dbc0387c5d3255d5c0db Mon Sep 17 00:00:00 2001
+From: Leah Rowe <leah@libreboot.org>
+Date: Wed, 1 Dec 2021 02:53:00 +0000
+Subject: [PATCH 16/22] fix speedstep on x200/t400: Revert
+ "cpu/intel/model_1067x: enable PECI"
+
+This reverts commit 70fea013c7ebd6d85a7806748233fcfd76802f5f.
+
+Enabling PECI without microcode updates loaded causes the CPUID feature set
+to become corrupted. And one consequence is broken SpeedStep. At least, that's
+my understanding looking at Intel Errata. This revert is not a fix, because
+upstream is correct (upstream assumes microcode updates). We will simply
+maintain this revert patch in Libreboot, from now on.
+---
+ src/cpu/intel/model_1067x/model_1067x_init.c | 9 ---------
+ 1 file changed, 9 deletions(-)
+
+diff --git a/src/cpu/intel/model_1067x/model_1067x_init.c b/src/cpu/intel/model_1067x/model_1067x_init.c
+index 315e7c36fc..1423fd72bc 100644
+--- a/src/cpu/intel/model_1067x/model_1067x_init.c
++++ b/src/cpu/intel/model_1067x/model_1067x_init.c
+@@ -141,8 +141,6 @@ static void configure_emttm_tables(void)
+ 	wrmsr(MSR_EMTTM_CR_TABLE(5), msr);
+ }
+ 
+-#define IA32_PECI_CTL		0x5a0
+-
+ static void configure_misc(const int eist, const int tm2, const int emttm)
+ {
+ 	msr_t msr;
+@@ -185,13 +183,6 @@ static void configure_misc(const int eist, const int tm2, const int emttm)
+ 		msr.lo |= (1 << 20);	/* Lock Enhanced SpeedStep Enable */
+ 		wrmsr(IA32_MISC_ENABLE, msr);
+ 	}
+-
+-	/* Enable PECI
+-	   WARNING: due to Erratum AW67 described in Intel document #318733
+-	   the microcode must be updated before this MSR is written to. */
+-	msr = rdmsr(IA32_PECI_CTL);
+-	msr.lo |= 1;
+-	wrmsr(IA32_PECI_CTL, msr);
+ }
+ 
+ #define PIC_SENS_CFG	0x1aa
+-- 
+2.39.2
+