x86: broadwell: Add reference code support

Broadwell needs a special binary blob to set up the PCH. Add code to run
this on start-up.

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

arch/x86/cpu/broadwell/Makefile

@@ -10,4 +10,5 @@ obj-y += lpc.o
 obj-y += northbridge.o
 obj-y += pch.o
 obj-y += pinctrl_broadwell.o
+obj-y += refcode.o
 obj-y += sata.o

arch/x86/cpu/broadwell/refcode.c

+/*
+ * Read a coreboot rmodule and execute it.
+ * The rmodule_header struct is from coreboot.
+ *
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <asm/arch/pei_data.h>
+
+#define RMODULE_MAGIC		0xf8fe
+#define RMODULE_VERSION_1	1
+
+/*
+ * All fields with '_offset' in the name are byte offsets into the flat blob.
+ * The linker and the linker script takes are of assigning the values.
+ */
+struct rmodule_header {
+	uint16_t magic;
+	uint8_t version;
+	uint8_t type;
+	/* The payload represents the program's loadable code and data */
+	uint32_t payload_begin_offset;
+	uint32_t payload_end_offset;
+	/* Begin and of relocation information about the program module */
+	uint32_t relocations_begin_offset;
+	uint32_t relocations_end_offset;
+	/*
+	 * The starting address of the linked program. This address is vital
+	 * for determining relocation offsets as the relocation info and other
+	 * symbols (bss, entry point) need this value as a basis to calculate
+	 * the offsets.
+	 */
+	uint32_t module_link_start_address;
+	/*
+	 * The module_program_size is the size of memory used while running
+	 * the program. The program is assumed to consume a contiguous amount
+	 * of memory
+	 */
+	uint32_t module_program_size;
+	/* This is program's execution entry point */
+	uint32_t module_entry_point;
+	/*
+	 * Optional parameter structure that can be used to pass data into
+	 * the module
+	 */
+	uint32_t parameters_begin;
+	uint32_t parameters_end;
+	/* BSS section information so the loader can clear the bss */
+	uint32_t bss_begin;
+	uint32_t bss_end;
+	/* Add some room for growth */
+	uint32_t padding[4];
+} __packed;
+
+int cpu_run_reference_code(void)
+{
+	struct pei_data _pei_data __aligned(8);
+	struct pei_data *pei_data = &_pei_data;
+	asmlinkage int (*func)(void *);
+	struct rmodule_header *hdr;
+	char *src, *dest;
+	int ret, dummy;
+	int size;
+
+	hdr = (struct rmodule_header *)CONFIG_X86_REFCODE_ADDR;
+	debug("Extracting code from rmodule at %p\n", hdr);
+	if (hdr->magic != RMODULE_MAGIC) {
+		debug("Invalid rmodule magic\n");
+		return -EINVAL;
+	}
+	if (hdr->module_link_start_address != 0) {
+		debug("Link start address must be 0\n");
+		return -EPERM;
+	}
+	if (hdr->module_entry_point != 0) {
+		debug("Entry point must be 0\n");
+		return -EPERM;
+	}
+
+	memset(pei_data, '\0', sizeof(struct pei_data));
+	broadwell_fill_pei_data(pei_data);
+	mainboard_fill_pei_data(pei_data);
+	pei_data->saved_data = (void *)&dummy;
+
+	src = (char *)hdr + hdr->payload_begin_offset;
+	dest = (char *)CONFIG_X86_REFCODE_RUN_ADDR;
+
+	size = hdr->payload_end_offset - hdr->payload_begin_offset;
+	debug("Copying refcode from %p to %p, size %x\n", src, dest, size);
+	memcpy(dest, src, size);
+
+	size = hdr->bss_end - hdr->bss_begin;
+	debug("Zeroing BSS at %p, size %x\n", dest + hdr->bss_begin, size);
+	memset(dest + hdr->bss_begin, '\0', size);
+
+	func = (asmlinkage int (*)(void *))dest;
+	debug("Running reference code at %p\n", func);
+#ifdef DEBUG
+	print_buffer(CONFIG_X86_REFCODE_RUN_ADDR, (void *)func, 1, 0x40, 0);
+#endif
+	ret = func(pei_data);
+	if (ret != 0) {
+		debug("Reference code returned %d\n", ret);
+		return -EL2HLT;
+	}
+	debug("Refereence code completed\n");
+
+	return 0;
+}