x86: apl: Use devicetree for FSP-M configuration

A the moment the FSP-M configuration is a mix of hard coded values and
devicetree properties.

This patch makes FSP-M full configurable from devicetree by adding
binding properties for all FSP-M parameters.

Co-developed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Signed-off-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Signed-off-by: Bernhard Messerklinger <bernhard.messerklinger@br-automation.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org> (Tested on coral)
[sjg: Fix a build error for coral]
Signed-off-by: Simon Glass <sjg@chromium.org>
[bmeng: Add __maybe_unused to fsp_update_config_from_dtb()]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/arch-apollolake/fsp_bindings.h b/arch/x86/include/asm/arch-apollolake/fsp_bindings.h
new file mode 100644
index 0000000..7f778ea
--- /dev/null
+++ b/arch/x86/include/asm/arch-apollolake/fsp_bindings.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ * Copyright 2020 B&R Industrial Automation GmbH - http://www.br-automation.com
+ */
+
+#ifndef __ASM_ARCH_FSP_BINDINGS_H
+#define __ASM_ARCH_FSP_BINDINGS_H
+
+#include <asm/arch/fsp/fsp_m_upd.h>
+
+#define ARRAY_SIZE_OF_MEMBER(s, m) (ARRAY_SIZE((((s *)0)->m)))
+#define SIZE_OF_MEMBER(s, m) (sizeof((((s *)0)->m)))
+
+enum conf_type {
+	FSP_UINT8,
+	FSP_UINT16,
+	FSP_UINT32,
+	FSP_STRING,
+	FSP_LPDDR4_SWIZZLE,
+};
+
+/**
+ * struct fsp_binding - Binding describing devicetree/FSP relationships
+ * @offset:   Offset within the FSP config structure
+ * @propname: Name of property to read
+ * @type:     Type of the property to read
+ * @count:    If the property is expected to be an array, this is the
+ *            number of expected elements
+ *            Set to 0 if the property is expected to be a scalar
+ *
+ * The struct fsp_binding is used to describe the relationship between
+ * values stored in devicetree and where they are placed in the FSP
+ * configuration structure.
+ */
+struct fsp_binding {
+	size_t offset;
+	char *propname;
+	enum conf_type type;
+	size_t count;
+};
+
+/*
+ * LPDDR4 helper routines for configuring the memory UPD for LPDDR4 operation.
+ * There are four physical LPDDR4 channels, each 32-bits wide. There are two
+ * logical channels using two physical channels together to form a 64-bit
+ * interface to memory for each logical channel.
+ */
+
+enum {
+	LP4_PHYS_CH0A,
+	LP4_PHYS_CH0B,
+	LP4_PHYS_CH1A,
+	LP4_PHYS_CH1B,
+
+	LP4_NUM_PHYS_CHANNELS,
+};
+
+/*
+ * The DQs within a physical channel can be bit-swizzled within each byte.
+ * Within a channel the bytes can be swapped, but the DQs need to be routed
+ * with the corresponding DQS (strobe).
+ */
+enum {
+	LP4_DQS0,
+	LP4_DQS1,
+	LP4_DQS2,
+	LP4_DQS3,
+
+	LP4_NUM_BYTE_LANES,
+	DQ_BITS_PER_DQS		= 8,
+};
+
+/* Provide bit swizzling per DQS and byte swapping within a channel */
+struct lpddr4_chan_swizzle_cfg {
+	u8 dqs[LP4_NUM_BYTE_LANES][DQ_BITS_PER_DQS];
+};
+
+struct lpddr4_swizzle_cfg {
+	struct lpddr4_chan_swizzle_cfg phys[LP4_NUM_PHYS_CHANNELS];
+};
+
+/**
+ * fsp_m_update_config_from_dtb() - Read FSP-M config from devicetree node
+ * @node: Valid node reference to read property from
+ * @cfg:  Pointer to FSP-M config structure
+ * @return 0 on success, -ve on error
+ *
+ * This function reads the configuration for FSP-M from the provided
+ * devicetree node and saves it in the FSP-M configuration structure.
+ * Configuration options that are not present in the devicetree are
+ * left at their current value.
+ */
+int fsp_m_update_config_from_dtb(ofnode node, struct fsp_m_config *cfg);
+
+#endif