x86: acpi: Add a common routine to write WiFi info

Intel WiFi chips can use a common routine to write the information needed
by linux. Add an implementation of this.

Enable it for coral.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/Kconfig

@@ -1009,4 +1009,12 @@ config INTEL_GMA_ACPI
 	  connected to the device. Enable this option to create this
 	  table so that graphics works correctly.
 
+config INTEL_GENERIC_WIFI
+	bool "Enable generation of ACPI tables for Intel WiFi"
+	help
+	  Select this option to provide code to a build generic WiFi ACPI table
+	  for Intel WiFi devices. This is not a WiFi driver and offers no
+	  network functionality. It is only here to generate the ACPI tables
+	  required by Linux.
+
 endmenu

arch/x86/cpu/intel_common/Makefile

@@ -24,6 +24,7 @@ obj-y += cpu.o
 obj-y += fast_spi.o
 obj-y += lpc.o
 obj-y += lpss.o
+obj-$(CONFIG_INTEL_GENERIC_WIFI) += generic_wifi.o
 ifndef CONFIG_TARGET_EFI_APP
 obj-$(CONFIG_$(SPL_TPL_)X86_32BIT_INIT) += microcode.o
 ifndef CONFIG_$(SPL_)X86_64

arch/x86/cpu/intel_common/generic_wifi.c

@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Generic WiFi ACPI info
+ *
+ * Copyright 2019 Google LLC
+ * Modified from coreboot src/drivers/wifi/generic.c
+ */
+
+#include <common.h>
+#include <log.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
+#include <dm.h>
+#include <dm/acpi.h>
+
+/* WRDS Spec Revision */
+#define WRDS_REVISION 0x0
+
+/* EWRD Spec Revision */
+#define EWRD_REVISION 0x0
+
+/* WRDS Domain type */
+#define WRDS_DOMAIN_TYPE_WIFI 0x7
+
+/* EWRD Domain type */
+#define EWRD_DOMAIN_TYPE_WIFI 0x7
+
+/* WGDS Domain type */
+#define WGDS_DOMAIN_TYPE_WIFI 0x7
+
+/*
+ * WIFI ACPI NAME = "WF" + hex value of last 8 bits of dev_path_encode + '\0'
+ * The above representation returns unique and consistent name every time
+ * generate_wifi_acpi_name is invoked. The last 8 bits of dev_path_encode is
+ * chosen since it contains the bus address of the device.
+ */
+#define WIFI_ACPI_NAME_MAX_LEN 5
+
+/**
+ * struct generic_wifi_config - Data structure to contain common wifi config
+ * @wake: Wake pin for ACPI _PRW
+ * @maxsleep: Maximum sleep state to wake from
+ */
+struct generic_wifi_config {
+	unsigned int wake;
+	unsigned int maxsleep;
+};
+
+static int generic_wifi_fill_ssdt(struct acpi_ctx *ctx,
+				  const struct udevice *dev,
+				  const struct generic_wifi_config *config)
+{
+	char name[ACPI_NAME_MAX];
+	char path[ACPI_PATH_MAX];
+	pci_dev_t bdf;
+	u32 address;
+	int ret;
+
+	ret = acpi_device_path(dev_get_parent(dev), path, sizeof(path));
+	if (ret)
+		return log_msg_ret("path", ret);
+	ret = acpi_get_name(dev, name);
+	if (ret)
+		return log_msg_ret("name", ret);
+
+	/* Device */
+	acpigen_write_scope(ctx, path);
+	acpigen_write_device(ctx, name);
+	acpigen_write_name_integer(ctx, "_UID", 0);
+	acpigen_write_name_string(ctx, "_DDN",
+				  dev_read_string(dev, "acpi,ddn"));
+
+	/* Address */
+	bdf = dm_pci_get_bdf(dev);
+	address = (PCI_DEV(bdf) << 16) | PCI_FUNC(bdf);
+	acpigen_write_name_dword(ctx, "_ADR", address);
+
+	/* Wake capabilities */
+	if (config)
+		acpigen_write_prw(ctx, config->wake, config->maxsleep);
+
+	acpigen_pop_len(ctx); /* Device */
+	acpigen_pop_len(ctx); /* Scope */
+
+	return 0;
+}
+
+static int intel_wifi_acpi_fill_ssdt(const struct udevice *dev,
+				     struct acpi_ctx *ctx)
+{
+	struct generic_wifi_config config;
+	bool have_config;
+	int ret;
+
+	ret = dev_read_u32(dev, "acpi,wake", &config.wake);
+	have_config = !ret;
+	/* By default, all intel wifi chips wake from S3 */
+	config.maxsleep = 3;
+	ret = generic_wifi_fill_ssdt(ctx, dev, have_config ? &config : NULL);
+	if (ret)
+		return log_msg_ret("wifi", ret);
+
+	return 0;
+}
+
+struct acpi_ops wifi_acpi_ops = {
+	.fill_ssdt	= intel_wifi_acpi_fill_ssdt,
+};
+
+static const struct udevice_id intel_wifi_ids[] = {
+	{ .compatible = "intel,generic-wifi" },
+	{ }
+};
+
+U_BOOT_DRIVER(intel_wifi) = {
+	.name		= "intel_wifi",
+	.id		= UCLASS_MISC,
+	.of_match	= intel_wifi_ids,
+	ACPI_OPS_PTR(&wifi_acpi_ops)
+};

configs/chromebook_coral_defconfig

@@ -18,6 +18,7 @@ CONFIG_HAVE_ACPI_RESUME=y
 CONFIG_INTEL_CAR_CQOS=y
 CONFIG_X86_OFFSET_U_BOOT=0xffe00000
 CONFIG_X86_OFFSET_SPL=0xffe80000
+CONFIG_INTEL_GENERIC_WIFI=y
 CONFIG_BOOTSTAGE=y
 CONFIG_SPL_BOOTSTAGE=y
 CONFIG_TPL_BOOTSTAGE=y