drivers/uart/acpi: Add new device driver for UART attached devices
This driver generates an ACPI device object for a UART attached device
with all of the expected device support handlers like different interrupt
sources and power control GPIOs.
Example use:
chip drivers/uart/acpi
register "name" = ""UDEV""
register "desc" = ""UART Attached Device""
register "hid" = "ACPI_DT_NAMESPACE_HID"
register "compat_string" = ""google,cros-ec-uart""
register "irq_gpio" = "ACPI_GPIO_IRQ_LEVEL_LOW_WAKE(GPP_C20)"
register "uart" = "ACPI_UART_RAW_DEVICE(115200, 64)"
device generic 0 on end
end
Resulting in this ACPI device:
Device (UDEV)
{
Name (_HID, "PRP0001")
Name (_UID, Zero)
Name (_DDN, "UART Attached Device")
Method (_STA, 0, NotSerialized)
{
Return (0x0F)
}
Name (_CRS, ResourceTemplate ()
{
UartSerialBusV2 (0x0001C200, DataBitsEight, StopBitsOne,
0x00, LittleEndian, ParityTypeNone, FlowControlNone,
0x0040, 0x0040, "\\_SB.PCI0.UAR2",
0x00, ResourceConsumer, , Exclusive)
GpioInt (Level, ActiveLow, ExclusiveAndWake, PullDefault, 0x0000,
"\\_SB.PCI0.GPIO", 0x00, ResourceConsumer)
{
0x0114
}
})
Name (_DSD, Package (0x02)
{
ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package (0x01)
{
Package (0x02)
{
"compatible",
"google,cros-ec-uart"
}
}
})
}
Change-Id: Idfd2d9d2ab6990a82ddd401734c0d9b1b0b8f82d
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41793
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/drivers/uart/acpi/Kconfig b/src/drivers/uart/acpi/Kconfig
new file mode 100644
index 0000000..de7dc82
--- /dev/null
+++ b/src/drivers/uart/acpi/Kconfig
@@ -0,0 +1,2 @@
+config DRIVERS_UART_ACPI
+ bool
diff --git a/src/drivers/uart/acpi/Makefile.inc b/src/drivers/uart/acpi/Makefile.inc
new file mode 100644
index 0000000..848deac
--- /dev/null
+++ b/src/drivers/uart/acpi/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_UART_ACPI) += acpi.c
diff --git a/src/drivers/uart/acpi/acpi.c b/src/drivers/uart/acpi/acpi.c
new file mode 100644
index 0000000..9b4d1fa
--- /dev/null
+++ b/src/drivers/uart/acpi/acpi.c
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
+#include <console/console.h>
+#include <device/path.h>
+#include <string.h>
+#include "chip.h"
+
+static bool uart_acpi_add_gpios_to_crs(struct drivers_uart_acpi_config *config)
+{
+ /*
+ * Return false if:
+ * 1. Request to explicitly disable export of GPIOs in CRS, or
+ * 2. Both reset and enable GPIOs are not provided.
+ */
+ if (config->disable_gpio_export_in_crs ||
+ ((config->reset_gpio.pin_count == 0) &&
+ (config->enable_gpio.pin_count == 0)))
+ return false;
+
+ return true;
+}
+
+static int uart_acpi_write_gpio(struct acpi_gpio *gpio, int *curr_index)
+{
+ int ret = -1;
+
+ if (gpio->pin_count == 0)
+ return ret;
+
+ acpi_device_write_gpio(gpio);
+ ret = *curr_index;
+ (*curr_index)++;
+
+ return ret;
+}
+
+static void uart_acpi_fill_ssdt(const struct device *dev)
+{
+ const char *scope = acpi_device_scope(dev);
+ const char *path = acpi_device_path(dev);
+ struct drivers_uart_acpi_config *config = dev->chip_info;
+ int curr_index = 0;
+ int irq_gpio_index = -1;
+ int reset_gpio_index = -1;
+ int enable_gpio_index = -1;
+
+ if (!dev->enabled || !scope)
+ return;
+
+ if (!config->hid) {
+ printk(BIOS_ERR, "%s: ERROR: HID required\n", dev_path(dev));
+ return;
+ }
+
+ acpigen_write_scope(scope);
+ acpigen_write_device(acpi_device_name(dev));
+
+ acpigen_write_name_string("_HID", config->hid);
+ if (config->cid)
+ acpigen_write_name_string("_CID", config->cid);
+ acpigen_write_name_integer("_UID", config->uid);
+ acpigen_write_name_string("_DDN", config->desc);
+ acpigen_write_STA(acpi_device_status(dev));
+
+ /* Resources */
+ acpigen_write_name("_CRS");
+ acpigen_write_resourcetemplate_header();
+
+ /* Fix up resource pointer to this scope */
+ config->uart.resource = scope;
+ acpi_device_write_uart(&config->uart);
+
+ /* Use either Interrupt() or GpioInt() */
+ if (config->irq_gpio.pin_count)
+ acpi_device_write_gpio(&config->irq_gpio);
+ else
+ acpi_device_write_interrupt(&config->irq);
+
+ /* Add enable/reset GPIOs if needed */
+ if (uart_acpi_add_gpios_to_crs(config)) {
+ reset_gpio_index = uart_acpi_write_gpio(&config->reset_gpio,
+ &curr_index);
+ enable_gpio_index = uart_acpi_write_gpio(&config->enable_gpio,
+ &curr_index);
+ }
+ acpigen_write_resourcetemplate_footer();
+
+ /* Wake capabilities */
+ if (config->wake) {
+ acpigen_write_name_integer("_S0W", ACPI_DEVICE_SLEEP_D3_COLD);
+ acpigen_write_PRW(config->wake, SLP_TYP_S3);
+ };
+
+ /* Write device properties if needed */
+ if (config->compat_string || irq_gpio_index >= 0 ||
+ reset_gpio_index >= 0 || enable_gpio_index >= 0) {
+ struct acpi_dp *dsd = acpi_dp_new_table("_DSD");
+ if (config->compat_string)
+ acpi_dp_add_string(dsd, "compatible",
+ config->compat_string);
+ if (irq_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "irq-gpios", path,
+ irq_gpio_index, 0,
+ config->irq_gpio.polarity);
+ if (reset_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "reset-gpios", path,
+ reset_gpio_index, 0,
+ config->reset_gpio.polarity);
+ if (enable_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "enable-gpios", path,
+ enable_gpio_index, 0,
+ config->enable_gpio.polarity);
+ acpi_dp_write(dsd);
+ }
+
+ /* Power Resource */
+ if (config->has_power_resource) {
+ const struct acpi_power_res_params power_res_params = {
+ &config->reset_gpio,
+ config->reset_delay_ms,
+ config->reset_off_delay_ms,
+ &config->enable_gpio,
+ config->enable_delay_ms,
+ config->enable_off_delay_ms,
+ &config->stop_gpio,
+ config->stop_delay_ms,
+ config->stop_off_delay_ms
+ };
+ acpi_device_add_power_res(&power_res_params);
+ }
+
+ acpigen_pop_len(); /* Device */
+ acpigen_pop_len(); /* Scope */
+
+ printk(BIOS_INFO, "%s: %s at %s\n", path, config->desc, dev_path(dev));
+}
+
+static const char *uart_acpi_name(const struct device *dev)
+{
+ struct drivers_uart_acpi_config *config = dev->chip_info;
+ static char name[5];
+
+ if (config->name)
+ return config->name;
+
+ snprintf(name, sizeof(name), "D%03.3X", dev->path.generic.id);
+ return name;
+}
+
+static struct device_operations uart_acpi_dev_ops = {
+ .read_resources = noop_read_resources,
+ .set_resources = noop_set_resources,
+ .acpi_fill_ssdt = uart_acpi_fill_ssdt,
+ .acpi_name = uart_acpi_name,
+};
+
+static void uart_acpi_enable(struct device *dev)
+{
+ struct drivers_uart_acpi_config *config = dev->chip_info;
+
+ if (config->desc)
+ dev->name = config->desc;
+ else
+ config->desc = dev->chip_ops->name;
+
+ dev->ops = &uart_acpi_dev_ops;
+}
+
+struct chip_operations drivers_uart_acpi_ops = {
+ CHIP_NAME("ACPI UART Device")
+ .enable_dev = uart_acpi_enable
+};
diff --git a/src/drivers/uart/acpi/chip.h b/src/drivers/uart/acpi/chip.h
new file mode 100644
index 0000000..0311165
--- /dev/null
+++ b/src/drivers/uart/acpi/chip.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __DRIVERS_UART_ACPI_H__
+#define __DRIVERS_UART_ACPI_H__
+
+#include <acpi/acpi_device.h>
+
+struct drivers_uart_acpi_config {
+ const char *hid; /* ACPI _HID (required) */
+ const char *cid; /* ACPI _CID */
+ const char *name; /* ACPI Device Name */
+ const char *desc; /* Device Description */
+ unsigned int uid; /* ACPI _UID */
+ unsigned int wake; /* Wake GPE */
+ const char *compat_string; /* Compatible string for _HID=PRP0001 */
+ struct acpi_irq irq; /* PIRQ */
+ struct acpi_gpio irq_gpio; /* GPIO to be used instead of PIRQ */
+ struct acpi_uart uart; /* UART device information */
+
+ /* Disable reset and enable GPIO export in _CRS */
+ bool disable_gpio_export_in_crs;
+
+ /* Does the device have a power resource? */
+ bool has_power_resource;
+
+ /* GPIO used to take device out of reset or to put it into reset. */
+ struct acpi_gpio reset_gpio;
+ /* Delay to be inserted after device is taken out of reset. */
+ unsigned int reset_delay_ms;
+ /* Delay to be inserted after device is put into reset. */
+ unsigned int reset_off_delay_ms;
+
+ /* GPIO used to enable device. */
+ struct acpi_gpio enable_gpio;
+ /* Delay to be inserted after device is enabled. */
+ unsigned int enable_delay_ms;
+ /* Delay to be inserted after device is disabled. */
+ unsigned int enable_off_delay_ms;
+
+ /* GPIO used to stop operation of device. */
+ struct acpi_gpio stop_gpio;
+ /* Delay to be inserted after disabling stop. */
+ unsigned int stop_delay_ms;
+ /* Delay to be inserted after enabling stop. */
+ unsigned int stop_off_delay_ms;
+};
+
+#endif /* __DRIVERS_UART_ACPI_H__ */