sb/intel/lynxpoint: Add native thermal init

Implement native thermal initialisation for Lynx Point. This is only
needed when MRC.bin is not used.

Change-Id: I4a67a3092d0c2e56bfdacb513a899ef838193cbd
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64180
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 64 insertions, 0 deletions

diff --git a/src/southbridge/intel/lynxpoint/thermal.c b/src/southbridge/intel/lynxpoint/thermal.c
new file mode 100644
index 0000000000..e71969ea0c
--- /dev/null
+++ b/src/southbridge/intel/lynxpoint/thermal.c
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <device/mmio.h>
+#include <device/pci_ops.h>
+#include <southbridge/intel/lynxpoint/pch.h>
+#include <types.h>
+
+#define TBARB_TEMP 0x40000000
+
+#define THERMAL_DEV PCI_DEV(0, 0x1f, 6)
+
+/* Early thermal init, it may need to be done prior to giving ME its memory */
+void early_thermal_init(void)
+{
+	/* Program address for temporary BAR */
+	pci_write_config32(THERMAL_DEV, 0x40, TBARB_TEMP);
+	pci_write_config32(THERMAL_DEV, 0x44, 0);
+
+	/* Activate temporary BAR */
+	pci_or_config32(THERMAL_DEV, 0x40, 1);
+
+	/*
+	 * BWG section 17.3.1 says:
+	 *
+	 * ### Initializing Lynx Point Thermal Sensors ###
+	 *
+	 * The System BIOS must perform the following steps to initialize the Lynx
+	 * Point thermal subsystem device, D31:F6. The System BIOS is required to
+	 * repeat this process on a resume from Sx. BIOS may enable any or all of
+	 * the registers below based on OEM's platform configuration. Intel does
+	 * not recommend a value on some of the registers, since each platform has
+	 * different temperature trip points and one may enable a trip to cause an
+	 * SMI while another platform would cause an interrupt instead.
+	 *
+	 * The recommended flow for enabling thermal sensor is by setting up various
+	 * temperature trip points first, followed by enabling the desired trip
+	 * alert method and then enable the actual sensors from TSEL registers.
+	 * If this flow is not followed, software will need to take special care
+	 * to handle false events during setting up those registers.
+	 */
+
+	/* Step 1: Program CTT */
+	write16p(TBARB_TEMP + 0x10, 0x0154);
+
+	/* Step 2: Clear trip status from TSS and TAS */
+	write8p(TBARB_TEMP + 0x06, 0xff);
+	write8p(TBARB_TEMP + 0x80, 0xff);
+
+	/* Step 3: Program TSGPEN and TSPIEN to zero */
+	write8p(TBARB_TEMP + 0x84, 0x00);
+	write8p(TBARB_TEMP + 0x82, 0x00);
+
+	/*
+	 * Step 4: If thermal reporting to an EC over SMBus is supported,
+	 *         then write 0x01 to TSREL, else leave at default.
+	 */
+	write8p(TBARB_TEMP + 0x0a, 0x01);
+
+	/* Disable temporary BAR */
+	pci_and_config32(THERMAL_DEV, 0x40, ~1);
+
+	/* Clear temporary BAR address */
+	pci_write_config32(THERMAL_DEV, 0x40, 0);
+}