x86: broadwell: Add support for high-speed I/O lane with ME

Provide a way to determine the HSIO (high-speed I/O) version supported by
the Intel Management Engine (ME) implementation on the platform.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/broadwell/Makefile

@@ -7,6 +7,7 @@
 obj-y += cpu.o
 obj-y += iobp.o
 obj-y += lpc.o
+obj-y += me.o
 obj-y += northbridge.o
 obj-y += pch.o
 obj-y += pinctrl_broadwell.o

arch/x86/cpu/broadwell/me.c

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ *
+ * Based on code from coreboot src/soc/intel/broadwell/me_status.c
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <asm/arch/me.h>
+
+static inline void me_read_dword_ptr(struct udevice *dev, void *ptr, int offset)
+{
+	u32 dword;
+
+	dm_pci_read_config32(dev, offset, &dword);
+	memcpy(ptr, &dword, sizeof(dword));
+}
+
+int intel_me_hsio_version(struct udevice *dev, uint16_t *versionp,
+			  uint16_t *checksump)
+{
+	int count;
+	u32 hsiover;
+	struct me_hfs hfs;
+
+	/* Query for HSIO version, overloads H_GS and HFS */
+	dm_pci_write_config32(dev, PCI_ME_H_GS,
+			      ME_HSIO_MESSAGE | ME_HSIO_CMD_GETHSIOVER);
+
+	/* Must wait for ME acknowledgement */
+	for (count = ME_RETRY; count > 0; --count) {
+		me_read_dword_ptr(dev, &hfs, PCI_ME_HFS);
+		if (hfs.bios_msg_ack)
+			break;
+		udelay(ME_DELAY);
+	}
+	if (!count) {
+		debug("ERROR: ME failed to respond\n");
+		return -ETIMEDOUT;
+	}
+
+	/* HSIO version should be in HFS_5 */
+	dm_pci_read_config32(dev, PCI_ME_HFS5, &hsiover);
+	*versionp = hsiover >> 16;
+	*checksump = hsiover & 0xffff;
+
+	debug("ME: HSIO Version            : %d (CRC 0x%04x)\n",
+	      *versionp, *checksump);
+
+	/* Reset registers to normal behavior */
+	dm_pci_write_config32(dev, PCI_ME_H_GS,
+			      ME_HSIO_MESSAGE | ME_HSIO_CMD_GETHSIOVER);
+
+	return 0;
+}