soc/intel/apollolake: Add support for GSPI

BUG=b:73133848
BRANCH=None
TEST=Build coreboot for Octopus board. Tested the GSPI interface
with a SPI EEPROM and got correct response to a RDID command

Change-Id: Iec96f926ba7162074090617b7cf1c84e36b0fb37
Signed-off-by: Ravi Sarawadi <ravishankar.sarawadi@intel.com>
Signed-off-by: Hannah Williams <hannah.williams@intel.com>
Reviewed-on: https://review.coreboot.org/24906
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/apollolake/gspi.c

@@ -0,0 +1,73 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 Google Inc.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <console/console.h>
+#include <device/device.h>
+#include <intelblocks/gspi.h>
+#include <intelblocks/spi.h>
+#include <soc/iomap.h>
+#include <soc/pci_devs.h>
+#include "chip.h"
+
+const struct gspi_cfg *gspi_get_soc_cfg(void)
+{
+	DEVTREE_CONST struct soc_intel_apollolake_config *config;
+	int devfn = SA_DEVFN_ROOT;
+	DEVTREE_CONST struct device *dev = dev_find_slot(0, devfn);
+
+	if (!dev || !dev->chip_info) {
+		printk(BIOS_ERR, "%s: Could not find SoC devicetree config!\n",
+		       __func__);
+		return NULL;
+	}
+
+	config = dev->chip_info;
+
+	return &config->gspi[0];
+}
+
+uintptr_t gspi_get_soc_early_base(void)
+{
+	return EARLY_GSPI_BASE_ADDRESS;
+}
+
+/*
+ * SPI Bus 0 is Fast SPI and GSPI starts from SPI bus # 1 onwards. Thus, adjust
+ * the bus # accordingly when referring to SPI / GSPI bus numbers.
+ */
+#define GSPI_TO_SPI_BUS(x)	(x)
+#define SPI_TO_GSPI_BUS(x)	((x) - 1)
+
+int gspi_soc_spi_to_gspi_bus(unsigned int spi_bus, unsigned int *gspi_bus)
+{
+	if (spi_bus == 0)
+		return -1;
+
+	if (SPI_TO_GSPI_BUS(spi_bus) >= CONFIG_SOC_INTEL_COMMON_BLOCK_GSPI_MAX)
+		return -1;
+
+	*gspi_bus = SPI_TO_GSPI_BUS(spi_bus);
+
+	return 0;
+}
+
+int gspi_soc_bus_to_devfn(unsigned int gspi_bus)
+{
+	if (gspi_bus >= CONFIG_SOC_INTEL_COMMON_BLOCK_GSPI_MAX)
+		return -1;
+
+	return spi_soc_bus_to_devfn(GSPI_TO_SPI_BUS(gspi_bus));
+}