soc/amd/common/block/lpc: Add helpers for managing eSPI decode

This change adds the following helper functions for eSPI decode:
1. espi_open_io_window() - Open generic IO window decoded by eSPI
2. espi_open_mmio_window() - Open generic MMIO window decoded by eSPI
3. espi_configure_decodes() - Configures standard and generic I/O
windows using the espi configuration provided by mainboard in device tree.

BUG=b:153675913,b:154445472

Change-Id: Idb49ef0477280eb46ecad65131d4cd7357618941
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41073
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

4 files changed, 331 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 6e3c973c97..b0348115e9 100644
--- a/src/soc/amd/common/block/include/amdblocks/chip.h
+++ b/src/soc/amd/common/block/include/amdblocks/chip.h
@@ -4,6 +4,7 @@
 #ifndef __AMDBLOCKS_CHIP_H__
 #define __AMDBLOCKS_CHIP_H__
 
+#include <amdblocks/espi.h>
 #include <amdblocks/spi.h>
 
 struct soc_amd_common_config {
@@ -17,6 +18,9 @@ struct soc_amd_common_config {
 	 * TPM speed - 66MHz
 	 */
 	struct spi_config spi_config;
+
+	/* eSPI configuration */
+	struct espi_config espi_config;
 };
 
 /*
diff --git a/src/soc/amd/common/block/include/amdblocks/espi.h b/src/soc/amd/common/block/include/amdblocks/espi.h
index 82410e58d3..53cc5f9f3f 100644
--- a/src/soc/amd/common/block/include/amdblocks/espi.h
+++ b/src/soc/amd/common/block/include/amdblocks/espi.h
@@ -4,6 +4,9 @@
 #ifndef __AMDBLOCKS_ESPI_H__
 #define __AMDBLOCKS_ESPI_H__
 
+#include <stdint.h>
+#include <stddef.h>
+
 /* eSPI MMIO base lives at an offset of 0x10000 from the address in SPI BAR. */
 #define ESPI_OFFSET_FROM_BAR			0x10000
 
@@ -24,4 +27,32 @@
 #define ESPI_GENERIC_MMIO_WIN_COUNT		4
 #define ESPI_GENERIC_MMIO_MAX_WIN_SIZE		0x10000
 
+struct espi_config {
+	/* Bitmap for standard IO decodes. Use ESPI_DECODE_IO_* above. */
+	uint32_t std_io_decode_bitmap;
+
+	struct {
+		uint16_t base;
+		size_t size;
+	} generic_io_range[ESPI_GENERIC_IO_WIN_COUNT];
+};
+
+/*
+ * Open I/O window using the provided base and size.
+ * Return value: 0 = success, -1 = error.
+ */
+int espi_open_io_window(uint16_t base, size_t size);
+
+/*
+ * Open MMIO window using the provided base and size.
+ * Return value: 0 = success, -1 = error.
+ */
+int espi_open_mmio_window(uint32_t base, size_t size);
+
+/*
+ * Configure generic and standard I/O decode windows using the espi_config structure settings
+ * provided by mainboard in device tree.
+ */
+void espi_configure_decodes(void);
+
 #endif /* __AMDBLOCKS_ESPI_H__ */
diff --git a/src/soc/amd/common/block/lpc/Makefile.inc b/src/soc/amd/common/block/lpc/Makefile.inc
index 72b1e42013..7db176b31d 100644
--- a/src/soc/amd/common/block/lpc/Makefile.inc
+++ b/src/soc/amd/common/block/lpc/Makefile.inc
@@ -6,3 +6,8 @@ romstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_LPC) += lpc_util.c
 postcar-$(CONFIG_SOC_AMD_COMMON_BLOCK_LPC) += lpc_util.c
 ramstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_LPC) += lpc_util.c
 smm-$(CONFIG_SOC_AMD_COMMON_BLOCK_LPC) += lpc_util.c
+
+bootblock-$(CONFIG_SOC_AMD_COMMON_BLOCK_USE_ESPI) += espi_util.c
+romstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_USE_ESPI) += espi_util.c
+ramstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_USE_ESPI) += espi_util.c
+verstage-$(CONFIG_SOC_AMD_COMMON_BLOCK_USE_ESPI) += espi_util.c
diff --git a/src/soc/amd/common/block/lpc/espi_util.c b/src/soc/amd/common/block/lpc/espi_util.c
new file mode 100644
index 0000000000..2585c46138
--- /dev/null
+++ b/src/soc/amd/common/block/lpc/espi_util.c
@@ -0,0 +1,291 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#include <amdblocks/chip.h>
+#include <amdblocks/espi.h>
+#include <amdblocks/lpc.h>
+#include <arch/mmio.h>
+#include <console/console.h>
+#include <soc/pci_devs.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <types.h>
+
+static uintptr_t espi_get_bar(void)
+{
+	uintptr_t espi_spi_base = lpc_get_spibase();
+	return espi_spi_base + ESPI_OFFSET_FROM_BAR;
+}
+
+static uint32_t espi_read32(int reg)
+{
+	return read32((void *)(espi_get_bar() + reg));
+}
+
+static void espi_write32(int reg, uint32_t val)
+{
+	write32((void *)(espi_get_bar() + reg), val);
+}
+
+static uint16_t espi_read16(int reg)
+{
+	return read16((void *)(espi_get_bar() + reg));
+}
+
+static void espi_write16(int reg, uint16_t val)
+{
+	write16((void *)(espi_get_bar() + reg), val);
+}
+
+static uint8_t espi_read8(int reg)
+{
+	return read8((void *)(espi_get_bar() + reg));
+}
+
+static void espi_write8(int reg, uint8_t val)
+{
+	write8((void *)(espi_get_bar() + reg), val);
+}
+
+static void espi_enable_decode(int decode_en)
+{
+	uint32_t val;
+
+	val = espi_read32(ESPI_DECODE);
+	val |= decode_en;
+	espi_write32(ESPI_DECODE, val);
+}
+
+static bool espi_is_decode_enabled(int decode)
+{
+	uint32_t val;
+
+	val = espi_read32(ESPI_DECODE);
+	return !!(val & decode);
+}
+
+static int espi_find_io_window(uint16_t win_base)
+{
+	int i;
+
+	for (i = 0; i < ESPI_GENERIC_IO_WIN_COUNT; i++) {
+		if (!espi_is_decode_enabled(ESPI_DECODE_IO_RANGE_EN(i)))
+			continue;
+
+		if (espi_read16(ESPI_IO_RANGE_BASE(i)) == win_base)
+			return i;
+	}
+
+	return -1;
+}
+
+static int espi_get_unused_io_window(void)
+{
+	int i;
+
+	for (i = 0; i < ESPI_GENERIC_IO_WIN_COUNT; i++) {
+		if (!espi_is_decode_enabled(ESPI_DECODE_IO_RANGE_EN(i)))
+			return i;
+	}
+
+	return -1;
+}
+
+/*
+ * Returns decode enable bits for standard IO port addresses. If port address is not supported
+ * by standard decode or if the size of window is not 1, then it returns -1.
+ */
+static int espi_std_io_decode(uint16_t base, size_t size)
+{
+	int ret = -1;
+
+	if (size != 1)
+		return ret;
+
+	switch (base) {
+	case 0x80:
+		ret = ESPI_DECODE_IO_0x80_EN;
+		break;
+	case 0x60:
+	case 0x64:
+		ret = ESPI_DECODE_IO_0X60_0X64_EN;
+		break;
+	case 0x2e:
+	case 0x2f:
+		ret = ESPI_DECODE_IO_0X2E_0X2F_EN;
+		break;
+	default:
+		ret = -1;
+		break;
+	}
+
+	return ret;
+}
+
+static size_t espi_get_io_window_size(int idx)
+{
+	return espi_read8(ESPI_IO_RANGE_SIZE(idx)) + 1;
+}
+
+static void espi_write_io_window(int idx, uint16_t base, size_t size)
+{
+	espi_write16(ESPI_IO_RANGE_BASE(idx), base);
+	espi_write8(ESPI_IO_RANGE_SIZE(idx), size - 1);
+}
+
+static int espi_open_generic_io_window(uint16_t base, size_t size)
+{
+	size_t win_size;
+	int idx;
+
+	for (; size; size -= win_size, base += win_size) {
+		win_size = MIN(size, ESPI_GENERIC_IO_MAX_WIN_SIZE);
+
+		idx = espi_find_io_window(base);
+		if (idx != -1) {
+			size_t curr_size = espi_get_io_window_size(idx);
+
+			if (curr_size > win_size) {
+				printk(BIOS_INFO, "eSPI window already configured to be larger than requested! ");
+				printk(BIOS_INFO, "Base: 0x%x, Requested size: 0x%zx, Actual size: 0x%zx\n",
+				       base, win_size, curr_size);
+			} else if (curr_size < win_size) {
+				espi_write_io_window(idx, base, win_size);
+				printk(BIOS_INFO, "eSPI window at base: 0x%x resized from 0x%zx to 0x%zx\n",
+				       base, curr_size, win_size);
+			}
+
+			continue;
+		}
+
+		idx = espi_get_unused_io_window();
+		if (idx == -1) {
+			printk(BIOS_ERR, "Cannot open IO window base %x size %zx\n", base,
+			       size);
+			printk(BIOS_ERR, "ERROR: No more available IO windows!\n");
+			return -1;
+		}
+
+		espi_write_io_window(idx, base, win_size);
+		espi_enable_decode(ESPI_DECODE_IO_RANGE_EN(idx));
+	}
+
+	return 0;
+}
+
+int espi_open_io_window(uint16_t base, size_t size)
+{
+	int std_io;
+
+	std_io = espi_std_io_decode(base, size);
+	if (std_io != -1) {
+		espi_enable_decode(std_io);
+		return 0;
+	}
+
+	return espi_open_generic_io_window(base, size);
+}
+
+static int espi_find_mmio_window(uint32_t win_base)
+{
+	int i;
+
+	for (i = 0; i < ESPI_GENERIC_MMIO_WIN_COUNT; i++) {
+		if (!espi_is_decode_enabled(ESPI_DECODE_MMIO_RANGE_EN(i)))
+			continue;
+
+		if (espi_read32(ESPI_MMIO_RANGE_BASE(i)) == win_base)
+			return i;
+	}
+
+	return -1;
+}
+
+static int espi_get_unused_mmio_window(void)
+{
+	int i;
+
+	for (i = 0; i < ESPI_GENERIC_MMIO_WIN_COUNT; i++) {
+		if (!espi_is_decode_enabled(ESPI_DECODE_MMIO_RANGE_EN(i)))
+			return i;
+	}
+
+	return -1;
+
+}
+
+static size_t espi_get_mmio_window_size(int idx)
+{
+	return espi_read16(ESPI_MMIO_RANGE_SIZE(idx)) + 1;
+}
+
+static void espi_write_mmio_window(int idx, uint32_t base, size_t size)
+{
+	espi_write32(ESPI_MMIO_RANGE_BASE(idx), base);
+	espi_write16(ESPI_MMIO_RANGE_SIZE(idx), size - 1);
+}
+
+int espi_open_mmio_window(uint32_t base, size_t size)
+{
+	size_t win_size;
+	int idx;
+
+	for (; size; size -= win_size, base += win_size) {
+		win_size = MIN(size, ESPI_GENERIC_MMIO_MAX_WIN_SIZE);
+
+		idx = espi_find_mmio_window(base);
+		if (idx != -1) {
+			size_t curr_size = espi_get_mmio_window_size(idx);
+
+			if (curr_size > win_size) {
+				printk(BIOS_INFO, "eSPI window already configured to be larger than requested! ");
+				printk(BIOS_INFO, "Base: 0x%x, Requested size: 0x%zx, Actual size: 0x%zx\n",
+				       base, win_size, curr_size);
+			} else if (curr_size < win_size) {
+				espi_write_mmio_window(idx, base, win_size);
+				printk(BIOS_INFO, "eSPI window at base: 0x%x resized from 0x%zx to 0x%zx\n",
+				       base, curr_size, win_size);
+			}
+
+			continue;
+		}
+
+		idx = espi_get_unused_mmio_window();
+		if (idx == -1) {
+			printk(BIOS_ERR, "Cannot open IO window base %x size %zx\n", base,
+			       size);
+			printk(BIOS_ERR, "ERROR: No more available MMIO windows!\n");
+			return -1;
+		}
+
+		espi_write_mmio_window(idx, base, win_size);
+		espi_enable_decode(ESPI_DECODE_MMIO_RANGE_EN(idx));
+	}
+
+	return 0;
+}
+
+static const struct espi_config *espi_get_config(void)
+{
+	const struct soc_amd_common_config *soc_cfg = soc_get_common_config();
+
+	if (!soc_cfg)
+		die("Common config structure is NULL!\n");
+
+	return &soc_cfg->espi_config;
+}
+
+void espi_configure_decodes(void)
+{
+	int i;
+	const struct espi_config *cfg = espi_get_config();
+
+	espi_enable_decode(cfg->std_io_decode_bitmap);
+
+	for (i = 0; i < ESPI_GENERIC_IO_WIN_COUNT; i++) {
+		if (cfg->generic_io_range[i].size == 0)
+			continue;
+		espi_open_generic_io_window(cfg->generic_io_range[i].base,
+					    cfg->generic_io_range[i].size);
+	}
+}