soc/intel/apollolake: Add utility functions for global reset

Apollolake defines Global Reset where Host, TXE and PMC are reset.
During boot we may need to trigger a global reset as part of platform
initialization (or for error handling). Add functions to trigger
global reset, enable/disable it and lock global reset bit.

BUG=chrome-os-partner:54149
BRANCH=none
TEST=none

Change-Id: I84296cd1560a0740f33ef6b488f15f99d397998d
Signed-off-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-on: https://review.coreboot.org/15198
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/Makefile.inc

@@ -29,6 +29,7 @@ romstage-y += meminit.c
 romstage-y += mmap_boot.c
 romstage-y += tsc_freq.c
 romstage-y += pmutil.c
+romstage-y += reset.c
 romstage-y += spi.c
 
 smm-y += mmap_boot.c
@@ -54,6 +55,7 @@ ramstage-y += spi.c
 ramstage-y += tsc_freq.c
 ramstage-y += pmutil.c
 ramstage-y += pmc.c
+ramstage-y += reset.c
 ramstage-y += smi.c
 ramstage-y += spi.c
 
@@ -70,6 +72,7 @@ verstage-y += mmap_boot.c
 verstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 verstage-y += tsc_freq.c
 verstage-y += pmutil.c
+verstage-y += reset.c
 verstage-y += spi.c
 
 CPPFLAGS_common += -I$(src)/soc/intel/apollolake/include

src/soc/intel/apollolake/include/soc/pm.h

@@ -128,6 +128,10 @@
 #define GEN_PMCON2		0x1024
 #       define RPS		(1 <<  2)
 #define GEN_PMCON3		0x1028
+#define ETR			0x1048
+#	define CF9_LOCK		(1 << 31)
+#	define CF9_GLB_RST	(1 << 20)
+
 
 /* Generic sleep state types */
 #define SLEEP_STATE_S0		0
@@ -168,4 +172,7 @@ void enable_gpe(uint32_t mask);
 void disable_gpe(uint32_t mask);
 void disable_all_gpe(void);
 
+void global_reset_enable(bool enable);
+void global_reset_lock(void);
+
 #endif

src/soc/intel/apollolake/pmutil.c

@@ -365,3 +365,34 @@ int vboot_platform_is_resuming(void)
 	typ = (inl(ACPI_PMIO_BASE + PM1_CNT) & SLP_TYP) >> SLP_TYP_SHIFT;
 	return typ == SLP_TYP_S3;
 }
+
+/*
+ * If possible, lock 0xcf9. Once the register is locked, it can't be changed.
+ * This lock is reset on cold boot, hard reset, soft reset and Sx.
+ */
+void global_reset_lock(void)
+{
+	uintptr_t etr = read_pmc_mmio_bar() + ETR;
+	uint32_t reg;
+
+	reg = read32((void *)etr);
+	if (reg & CF9_LOCK)
+		return;
+	reg |= CF9_LOCK;
+	write32((void *)etr, reg);
+}
+
+/*
+ * Enable or disable global reset. If global reset is enabled, hard reset and
+ * soft reset will trigger global reset, where both host and TXE are reset.
+ * This is cleared on cold boot, hard reset, soft reset and Sx.
+ */
+void global_reset_enable(bool enable)
+{
+	uintptr_t etr = read_pmc_mmio_bar() + ETR;
+	uint32_t reg;
+
+	reg = read32((void *)etr);
+	reg = enable ? reg | CF9_GLB_RST : reg & ~CF9_GLB_RST;
+	write32((void *)etr, reg);
+}

src/soc/intel/apollolake/reset.c

@@ -0,0 +1,23 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <reset.h>
+#include <soc/pm.h>
+
+void global_reset(void)
+{
+	global_reset_enable(1);
+	hard_reset();
+}