soc/amd/common/block/spi: Add support for common SPI configuration

This change adds support for following SPI configuration functions to
common block SPI driver and exposes them to be used by SoC:
1. fch_spi_early_init(): Sets up SPI ROM base, enables SPI ROM,
enables prefetching, disables 4dw burst mode and sets SPI speed and mode.
2. fch_spi_config_modes(): This allows SoC to configure SPI speed and
mode. It uses SPI settings from soc_amd_common_config to configure the
speed and mode.

These functions expect SoC to include soc_amd_common_config in SoC
chip config and mainboard to configure these settings in device tree.

Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: Ia4f231bab69e8450005dd6abe7a8e014d5eb7261
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41248
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 109 insertions, 0 deletions

diff --git a/src/soc/amd/common/block/include/amdblocks/chip.h b/src/soc/amd/common/block/include/amdblocks/chip.h
index 26ad26a6b1..6e3c973c97 100644
--- a/src/soc/amd/common/block/include/amdblocks/chip.h
+++ b/src/soc/amd/common/block/include/amdblocks/chip.h
@@ -4,7 +4,19 @@
 #ifndef __AMDBLOCKS_CHIP_H__
 #define __AMDBLOCKS_CHIP_H__
 
+#include <amdblocks/spi.h>
+
 struct soc_amd_common_config {
+	/*
+	 * SPI configuration
+	 * Default values if not overridden by mainboard:
+	 * Read mode - Normal 33MHz
+	 * Normal speed - 66MHz
+	 * Fast speed - 66MHz
+	 * Alt speed - 66MHz
+	 * TPM speed - 66MHz
+	 */
+	struct spi_config spi_config;
 };
 
 /*
diff --git a/src/soc/amd/common/block/include/amdblocks/spi.h b/src/soc/amd/common/block/include/amdblocks/spi.h
new file mode 100644
index 0000000000..d901f7e020
--- /dev/null
+++ b/src/soc/amd/common/block/include/amdblocks/spi.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#ifndef __AMDBLOCKS_SPI_H__
+#define __AMDBLOCKS_SPI_H__
+
+#define SPI_CNTRL0			0x00
+#define   SPI_BUSY			BIT(31)
+
+enum spi_read_mode {
+	SPI_READ_MODE_NORMAL33M = 0,
+	/* 1 is reserved. */
+	SPI_READ_MODE_DUAL112 = 2,
+	SPI_READ_MODE_QUAD114 = 3,
+	SPI_READ_MODE_DUAL122 = 4,
+	SPI_READ_MODE_QUAD144 = 5,
+	SPI_READ_MODE_NORMAL66M = 6,
+	SPI_READ_MODE_FAST_READ = 7,
+};
+/*
+ * SPI read mode is split into bits 18, 29, 30 such that [30:29:18] correspond to bits [2:0] for
+ * SpiReadMode.
+ */
+#define   SPI_READ_MODE_MASK		(BIT(30) | BIT(29) | BIT(18))
+#define   SPI_READ_MODE_UPPER_BITS(x)	((((x) >> 1) & 0x3) << 29)
+#define   SPI_READ_MODE_LOWER_BITS(x)	(((x) & 0x1) << 18)
+#define   SPI_READ_MODE(x)		(SPI_READ_MODE_UPPER_BITS(x) | \
+					 SPI_READ_MODE_LOWER_BITS(x))
+#define   SPI_ACCESS_MAC_ROM_EN		BIT(22)
+
+#define SPI100_ENABLE			0x20
+#define   SPI_USE_SPI100		BIT(0)
+
+/* Use SPI_SPEED_16M-SPI_SPEED_66M below for the southbridge */
+#define SPI100_SPEED_CONFIG		0x22
+enum spi100_speed {
+	SPI_SPEED_66M = 0,
+	SPI_SPEED_33M = 1,
+	SPI_SPEED_22M = 2,
+	SPI_SPEED_16M = 3,
+	SPI_SPEED_100M = 4,
+	SPI_SPEED_800K = 5,
+};
+
+#define   SPI_SPEED_MASK		0xf
+#define   SPI_SPEED_MODE(x, shift)	(((x) & SPI_SPEED_MASK) << shift)
+#define   SPI_NORM_SPEED(x)		SPI_SPEED_MODE(x, 12)
+#define   SPI_FAST_SPEED(x)		SPI_SPEED_MODE(x, 8)
+#define   SPI_ALT_SPEED(x)		SPI_SPEED_MODE(x, 4)
+#define   SPI_TPM_SPEED(x)		SPI_SPEED_MODE(x, 0)
+
+#define   SPI_SPEED_CFG(n, f, a, t)	(SPI_NORM_SPEED(n) | SPI_FAST_SPEED(f) | \
+					 SPI_ALT_SPEED(a) | SPI_TPM_SPEED(t))
+
+#define SPI100_HOST_PREF_CONFIG		0x2c
+#define   SPI_RD4DW_EN_HOST		BIT(15)
+
+#define SPI_FIFO			0x80
+#define   SPI_FIFO_DEPTH		(0xc7 - SPI_FIFO)
+
+struct spi_config {
+	/*
+	 * Default values if not overridden by mainboard:
+	 * Read mode - Normal 33MHz
+	 * Normal speed - 66MHz
+	 * Fast speed - 66MHz
+	 * Alt speed - 66MHz
+	 * TPM speed - 66MHz
+	 */
+	enum spi_read_mode read_mode;
+	enum spi100_speed normal_speed;
+	enum spi100_speed fast_speed;
+	enum spi100_speed altio_speed;
+	enum spi100_speed tpm_speed;
+};
+
+/*
+ * Perform early SPI initialization:
+ * 1. Sets SPI ROM base and enables SPI ROM
+ * 2. Enables SPI ROM prefetching
+ * 3. Disables 4dw burst
+ * 4. Configures SPI speed and read mode.
+ *
+ * This function expects SoC to include soc_amd_common_config in chip SoC config and uses
+ * settings from mainboard devicetree to configure speed and read mode.
+ */
+void fch_spi_early_init(void);
+
+/*
+ * Configure SPI speed and read mode.
+ *
+ * This function expects SoC to include soc_amd_common_config in chip SoC config and uses
+ * settings from mainboard devicetree to configure speed and read mode.
+ */
+void fch_spi_config_modes(void);
+
+#endif /* __AMDBLOCKS_SPI_H__ */