drivers/wwan/fm: Add Fibocom 5G WWAN ACPI support

Support PXSX._RST and PXSX.MRST._RST for warm and cold reset.
PXSX._RST is invoked on driver removal.

build dependency:
  soc/intel/common/block/pcie/rtd3

This driver will use the rtd3 methods for the same parent in the device
tree. The rtd3 chip needs to be added on the same root port in the
devicetree separately.

Test:
Add chip entry to the corresponding root port and check PXSX Device
is generated in ssdt.

Signed-off-by: Cliff Huang <cliff.huang@intel.com>
Change-Id: I1e0b9fd405f6cfb1e216ea27558bb9299a09e566
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61354
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

4 files changed, 294 insertions, 0 deletions

diff --git a/src/drivers/wwan/fm/Kconfig b/src/drivers/wwan/fm/Kconfig
new file mode 100644
index 0000000000..bed3b2e5ac
--- /dev/null
+++ b/src/drivers/wwan/fm/Kconfig
@@ -0,0 +1,11 @@
+config DRIVERS_WWAN_FM350GL
+	bool
+	default n
+	depends on SOC_INTEL_COMMON_BLOCK_PCIE_RTD3
+	help
+	   This driver is for Fibocom FM350-GL PCIe 5G WWAN.
+	   When enabled, this driver will add support for ACPI controlled
+	   WWAN using GPIOs for power/reset control of the device.
+	   This driver depends on rtd3 driver code to build as it needs to
+	   point to the rtd3 chip on the same parent for the methods provided
+	   only for the same root port.
diff --git a/src/drivers/wwan/fm/Makefile.inc b/src/drivers/wwan/fm/Makefile.inc
new file mode 100644
index 0000000000..8074a0869a
--- /dev/null
+++ b/src/drivers/wwan/fm/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_WWAN_FM350GL) += acpi_fm350gl.c
diff --git a/src/drivers/wwan/fm/acpi_fm350gl.c b/src/drivers/wwan/fm/acpi_fm350gl.c
new file mode 100644
index 0000000000..15d0ecc859
--- /dev/null
+++ b/src/drivers/wwan/fm/acpi_fm350gl.c
@@ -0,0 +1,257 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
+#include "chip.h"
+#include "soc/intel/common/block/pcie/rtd3/chip.h"
+
+/* FCPO# to RESET# delay time during WWAN ON */
+#define FM350GL_TN2B 20
+/* RESET# to PERST# delay time during WWAN ON */
+#define FM350GL_TB2R 80
+/* The delay between de-assertion of PERST# to change of PDS state from 0 to 1 during WWAN ON */
+#define FM350GL_TR2P 0
+/* RESET# to FCPO# delay time during WWAN OFF */
+#define FM350GL_TB2F 10
+/* Time to allow the WWAN module to fully discharge any residual voltages before FCPO# could be
+   de-asserted again. */
+#define FM350GL_TFDI 500
+/* The delay between assertion and de-assertion RESET# during FLDR */
+#define FM350GL_TBTG 10
+/* The delay between de-assertion of RESET# and change of PDS state from 0 to 1 after FLDR */
+#define FM350GL_TBTP 170
+/* PERST# to RESET# delay time during WWAN OFF */
+#define FM350GL_TR2B 10
+/* 20s HW initialization needed after de-assertion of PERST#
+   However, it is not required and is not proper place to ensure HW initialization in ACPI. The
+   delay here is to ensure the following reset or RTD3 _OFF method won't be called immediately.
+ */
+#define FM350GL_TIME_HW_INIT 100
+
+enum reset_type {
+	RESET_TYPE_WARM = 0,
+	RESET_TYPE_COLD = 1
+};
+
+/*
+ *  Returns the RTD3 PM methods requested and available to the device.
+ */
+static enum acpi_pcie_rp_pm_emit
+wwan_fm350gl_get_rtd3_method_support(const struct drivers_wwan_fm_config *config)
+{
+	const struct soc_intel_common_block_pcie_rtd3_config *rtd3_config;
+
+	rtd3_config = config_of(config->rtd3dev);
+
+	return rtd3_config->ext_pm_support;
+}
+
+/*
+ *  Generate first half reset flow (FHRF) method.
+ *  Arg0 = RESET_TYPE_WARM: warm reset
+ *  Arg0 = 1RESET_TYPE_COLD: cold reset
+ */
+static void wwan_fm350gl_acpi_method_fhrf(const struct device *parent_dev,
+	const struct drivers_wwan_fm_config *config)
+{
+	acpigen_write_method_serialized("FHRF", 1);
+	{
+		/* LOCAL0 = PERST# */
+		acpigen_get_tx_gpio(&config->perst_gpio);
+		acpigen_write_if_lequal_op_int(LOCAL0_OP, 0);
+		{
+			if (wwan_fm350gl_get_rtd3_method_support(config) |
+				ACPI_PCIE_RP_EMIT_L23) {
+				acpigen_emit_namestring(acpi_device_path_join(parent_dev,
+					"DL23"));
+			}
+			/* assert PERST# pin */
+			acpigen_enable_tx_gpio(&config->perst_gpio);
+		}
+		acpigen_write_if_end(); /* If */
+		acpigen_write_sleep(FM350GL_TR2B);
+		/* assert RESET# pin */
+		acpigen_enable_tx_gpio(&config->reset_gpio);
+		/* warm reset */
+		acpigen_write_if_lequal_op_int(ARG0_OP, RESET_TYPE_WARM);
+		{
+			acpigen_write_sleep(FM350GL_TBTG);
+		}
+		/* cold reset */
+		acpigen_write_else();
+		{
+			acpigen_write_if_lequal_op_int(ARG0_OP, RESET_TYPE_COLD);
+			{
+				/* disable source clock */
+				if (wwan_fm350gl_get_rtd3_method_support(config) |
+					ACPI_PCIE_RP_EMIT_SRCK) {
+					acpigen_emit_namestring(acpi_device_path_join(
+						parent_dev, "SRCK"));
+					acpigen_emit_byte(ZERO_OP);
+				}
+				acpigen_write_sleep(FM350GL_TB2F);
+				/* assert FCPO# pin */
+				acpigen_enable_tx_gpio(&config->fcpo_gpio);
+				acpigen_write_sleep(FM350GL_TFDI);
+			}
+			acpigen_write_if_end(); /* If */
+		}
+		acpigen_pop_len(); /* Else */
+	}
+	acpigen_write_method_end(); /* Method */
+}
+
+/*
+ *  Generate second half reset flow (SHRF) method.
+ */
+static void wwan_fm350gl_acpi_method_shrf(const struct device *parent_dev,
+		const struct drivers_wwan_fm_config *config)
+{
+	acpigen_write_method_serialized("SHRF", 0);
+	{
+		/* call rtd3 method to Disable ModPHY Power Gating. */
+		if (wwan_fm350gl_get_rtd3_method_support(config) |
+			ACPI_PCIE_RP_EMIT_PSD0) {
+			acpigen_emit_namestring(acpi_device_path_join(parent_dev,
+				"PSD0"));
+		}
+		/* call rtd3 method to Enable SRC Clock. */
+		if (wwan_fm350gl_get_rtd3_method_support(config) |
+			ACPI_PCIE_RP_EMIT_SRCK) {
+			acpigen_emit_namestring(acpi_device_path_join(parent_dev,
+				"SRCK"));
+			acpigen_emit_byte(ONE_OP);
+		}
+		/* De-assert FCPO# GPIO. */
+		acpigen_disable_tx_gpio(&config->fcpo_gpio);
+		acpigen_write_sleep(FM350GL_TN2B);
+		/* De-assert RESET# GPIO. */
+		acpigen_disable_tx_gpio(&config->reset_gpio);
+		acpigen_write_sleep(FM350GL_TB2R);
+		/* De-assert PERST# GPIO. */
+		acpigen_disable_tx_gpio(&config->perst_gpio);
+		/* Call rtd3 method to trigger L2/L3 ready exit flow in root port */
+		if (wwan_fm350gl_get_rtd3_method_support(config) |
+			ACPI_PCIE_RP_EMIT_L23) {
+			acpigen_emit_namestring(acpi_device_path_join(parent_dev,
+				"L23D"));
+		}
+		acpigen_write_sleep(FM350GL_TIME_HW_INIT);
+	}
+	acpigen_write_method_end(); /* Method */
+}
+
+/*
+ * Generate _RST method. This is to perform a soft reset. It is added under
+ * PXSX. This is called during device driver removal.
+ */
+static void wwan_fm350gl_acpi_method_rst(const struct device *parent_dev,
+			 const struct drivers_wwan_fm_config *config)
+{
+	acpigen_write_method_serialized("_RST", 0);
+	{
+		/* Perform 1st Half of FLDR Flow for soft reset: FHRF(0) */
+		acpigen_emit_namestring("FHRF");
+		acpigen_emit_byte(RESET_TYPE_WARM);
+		/* Perform 2nd Half of FLDR Flow: SHRF() */
+		acpigen_emit_namestring("SHRF");
+		/* Indicates that the following _Off will be skipped. */
+		acpigen_emit_byte(INCREMENT_OP);
+		acpigen_emit_namestring(acpi_device_path_join(parent_dev, "RTD3.OFSK"));
+	}
+	acpigen_write_method_end(); /* Method */
+}
+
+/*
+ * Generate _RST method. This is to perform a cold reset. This reset will be
+ * included under PXSX.MRST. This method is used during device firmware update.
+ */
+static void wwan_fm350gl_acpi_method_mrst_rst(const struct device *parent_dev,
+			 const struct drivers_wwan_fm_config *config)
+{
+	acpigen_write_method_serialized("_RST", 0);
+	{
+		/* Perform 1st Half of FLDR Flow for cold reset: FHRF (1) */
+		acpigen_emit_namestring("FHRF");
+		acpigen_emit_byte(RESET_TYPE_COLD);
+		/* Perform 2nd Half of FLDR Flow: SHRF () */
+		acpigen_emit_namestring("SHRF");
+		/* Indicate kernel ACPI PM to skip _off RTD3 after reset at the end of
+		   driver removal */
+		acpigen_emit_byte(INCREMENT_OP);
+		acpigen_emit_namestring(acpi_device_path_join(parent_dev, "RTD3.OFSK"));
+	}
+	acpigen_write_method_end(); /* Method */
+}
+
+static const char *wwan_fm350gl_acpi_name(const struct device *dev)
+{
+	/* Attached device name must be "PXSX" for the Linux Kernel to recognize it. */
+	return "PXSX";
+}
+
+static void wwan_fm350gl_acpi_fill_ssdt(const struct device *dev)
+{
+	const struct drivers_wwan_fm_config *config = config_of(dev);
+	const struct device *parent = dev->bus->dev;
+	const char *scope = acpi_device_path(parent);
+
+	if (!is_dev_enabled(parent)) {
+		printk(BIOS_ERR, "%s: root port not enabled\n", __func__);
+		return;
+	}
+	if (!scope) {
+		printk(BIOS_ERR, "%s: root port scope not found\n", __func__);
+		return;
+	}
+	if (!config->fcpo_gpio.pin_count && !config->reset_gpio.pin_count &&
+		!config->perst_gpio.pin_count) {
+		printk(BIOS_ERR, "%s: FCPO, RESET, PERST GPIO required for %s.\n",
+			 __func__, scope);
+		return;
+	}
+	printk(BIOS_INFO, "%s: Enable WWAN for %s (%s)\n", scope, dev_path(parent),
+		config->desc ?: dev->chip_ops->name);
+	acpigen_write_scope(scope);
+	{
+		acpigen_write_device(wwan_fm350gl_acpi_name(dev));
+		{
+			acpigen_write_ADR(0);
+			if (config->name)
+				acpigen_write_name_string("_DDN", config->name);
+			if (config->desc)
+				acpigen_write_name_unicode("_STR", config->desc);
+			wwan_fm350gl_acpi_method_fhrf(parent, config);
+			wwan_fm350gl_acpi_method_shrf(parent, config);
+			wwan_fm350gl_acpi_method_rst(parent, config);
+			/* NOTE: the 5G driver will call MRST._RST to trigger a cold reset
+			 * during firmware update.
+			 */
+			acpigen_write_device("MRST");
+			{
+				acpigen_write_ADR(0);
+				wwan_fm350gl_acpi_method_mrst_rst(parent, config);
+			}
+			acpigen_write_device_end(); /* Device */
+		}
+		acpigen_write_device_end(); /* Device */
+	}
+	acpigen_write_scope_end(); /* Scope */
+}
+
+static struct device_operations wwan_fm350gl_ops = {
+	.read_resources  = noop_read_resources,
+	.set_resources   = noop_set_resources,
+	.acpi_fill_ssdt  = wwan_fm350gl_acpi_fill_ssdt,
+	.acpi_name       = wwan_fm350gl_acpi_name,
+};
+
+static void wwan_fm350gl_acpi_enable(struct device *dev)
+{
+	dev->ops = &wwan_fm350gl_ops;
+}
+
+struct chip_operations drivers_wwan_fm_ops = {
+	 CHIP_NAME("Fibocom FM-350-GL")
+	.enable_dev = wwan_fm350gl_acpi_enable
+};
diff --git a/src/drivers/wwan/fm/chip.h b/src/drivers/wwan/fm/chip.h
new file mode 100644
index 0000000000..635178bd16
--- /dev/null
+++ b/src/drivers/wwan/fm/chip.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __DRIVERS_WWAN_FM_CHIP_H__
+#define __DRIVERS_WWAN_FM_CHIP_H__
+
+struct drivers_wwan_fm_config {
+	const char *name;
+	const char *desc;
+	/* GPIO used for FULL_CARD_POWER_OFF# */
+	struct acpi_gpio fcpo_gpio;
+
+	/* GPIO used for RESET# */
+	struct acpi_gpio reset_gpio;
+
+	/* GPIO used for PERST# */
+	struct acpi_gpio perst_gpio;
+
+	/* GPIO used for wake */
+	struct acpi_gpio wake_gpio;
+
+	/* Pointer to the corresponding RTD3 */
+	DEVTREE_CONST struct device *rtd3dev;
+};
+
+#endif /* __DRIVERS_WWAN_FM_CHIP_H__ */