diff options
| -rw-r--r-- | Documentation/drivers/retimer.md | 40 | ||||
| -rw-r--r-- | Makefile.inc | 2 | ||||
| -rw-r--r-- | src/Kconfig | 1 | ||||
| -rw-r--r-- | src/drivers/intel/usb4/retimer/Kconfig | 8 | ||||
| -rw-r--r-- | src/drivers/intel/usb4/retimer/Makefile.inc | 1 | ||||
| -rw-r--r-- | src/drivers/intel/usb4/retimer/chip.h | 13 | ||||
| -rw-r--r-- | src/drivers/intel/usb4/retimer/retimer.c | 136 |
7 files changed, 200 insertions, 1 deletions
diff --git a/Documentation/drivers/retimer.md b/Documentation/drivers/retimer.md new file mode 100644 index 0000000000..d83b50b26f --- /dev/null +++ b/Documentation/drivers/retimer.md @@ -0,0 +1,40 @@ +# USB4 Retimers + +# Introduction +As USB speeds continue to increase (up to 5G, 10G, and even 20G or higher in +newer revisions of the spec), it becomes more difficult to maintain signal +integrity for longer traces. Devices such as retimers and redrivers can be used +to help signals maintain their integrity over long distances. + +A redriver is a device that boosts the high-frequency content of a signal in +order to compensate for the attenuation typically caused by travelling through +various circuit components (PCB, connectors, CPU, etc.). Redrivers are not +protocol-aware, which makes them relatively simple. However, their effectiveness +is limited, and may not work at all in some scenarios. + +A retimer is a device that retransmits a fresh copy of the signal it receives, +by doing CDR and retransmitting the data (i.e., it is protocol-aware). Since +this is a digital component, it may have firmware. + + +# Driver Usage + +Some operating systems may have the ability to update firmware on USB4 retimers, +and ultimately will need some way to power the device on and off so that its new +firmware can be loaded. This is achieved by providing a GPIO signal that can be +used for this purpose; its active state must be the one in which power is +applied to the retimer. This driver will generate the required ACPI AML code +which will toggle the GPIO in response to the kernel's request (through the +`_DSM` ACPI method). Simply put something like the following in your devicetree: + +``` +device pci 0.0 on + chip drivers/intel/usb4/retimer + register "power_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPP_A0)" + device generic 0 on end + end +end +``` + +replacing the GPIO with the appropriate pin and polarity. + diff --git a/Makefile.inc b/Makefile.inc index 882673b4c9..297f7b1a16 100644 --- a/Makefile.inc +++ b/Makefile.inc @@ -80,7 +80,7 @@ subdirs-y := src/lib src/commonlib/ src/console src/device src/acpi subdirs-y += src/ec/acpi $(wildcard src/ec/*/*) $(wildcard src/southbridge/*/*) subdirs-y += $(wildcard src/soc/*/*) $(wildcard src/northbridge/*/*) subdirs-y += src/superio -subdirs-y += $(wildcard src/drivers/*) $(wildcard src/drivers/*/*) +subdirs-y += $(wildcard src/drivers/*) $(wildcard src/drivers/*/*) $(wildcard src/drivers/*/*/*) subdirs-y += src/cpu src/vendorcode subdirs-y += util/cbfstool util/sconfig util/nvramtool util/pgtblgen util/amdfwtool subdirs-y += util/futility util/marvell util/bincfg util/supermicro diff --git a/src/Kconfig b/src/Kconfig index 9cc9d31e64..d265da7797 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -554,6 +554,7 @@ source "src/device/Kconfig" menu "Generic Drivers" source "src/drivers/*/Kconfig" source "src/drivers/*/*/Kconfig" +source "src/drivers/*/*/*/Kconfig" source "src/commonlib/storage/Kconfig" endmenu diff --git a/src/drivers/intel/usb4/retimer/Kconfig b/src/drivers/intel/usb4/retimer/Kconfig new file mode 100644 index 0000000000..eee8fe1bed --- /dev/null +++ b/src/drivers/intel/usb4/retimer/Kconfig @@ -0,0 +1,8 @@ +config DRIVERS_INTEL_USB4_RETIMER + bool + depends on HAVE_ACPI_TABLES + help + A retimer is a device that retransmits a fresh copy of the signal it + receives, by doing CDR and retransmitting the data (i.e., it is + protocol-aware). If your mainboard has a USB4 retimer (usually + located close to the USB4 ports), then select this driver. diff --git a/src/drivers/intel/usb4/retimer/Makefile.inc b/src/drivers/intel/usb4/retimer/Makefile.inc new file mode 100644 index 0000000000..bca23aa3bf --- /dev/null +++ b/src/drivers/intel/usb4/retimer/Makefile.inc @@ -0,0 +1 @@ +ramstage-$(CONFIG_DRIVERS_INTEL_USB4_RETIMER) += retimer.c diff --git a/src/drivers/intel/usb4/retimer/chip.h b/src/drivers/intel/usb4/retimer/chip.h new file mode 100644 index 0000000000..789d824a81 --- /dev/null +++ b/src/drivers/intel/usb4/retimer/chip.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef __DRIVERS_INTEL_USB4_RETIMER_H__ +#define __DRIVERS_INTEL_USB4_RETIMER_H__ + +#include <acpi/acpi_device.h> + +struct drivers_intel_usb4_retimer_config { + /* GPIO used to control power of retimer device. */ + struct acpi_gpio power_gpio; +}; + +#endif /* __DRIVERS_INTEL_USB4_RETIMER_H__ */ diff --git a/src/drivers/intel/usb4/retimer/retimer.c b/src/drivers/intel/usb4/retimer/retimer.c new file mode 100644 index 0000000000..be9ec35230 --- /dev/null +++ b/src/drivers/intel/usb4/retimer/retimer.c @@ -0,0 +1,136 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <acpi/acpigen.h> +#include <acpi/acpi_device.h> +#include <console/console.h> +#include <device/device.h> +#include <device/path.h> +#include <gpio.h> +#include <string.h> +#include "chip.h" + +/* Unique ID for the retimer _DSM. */ +#define INTEL_USB4_RETIMER_DSM_UUID "61788900-C470-42BB-80F0-23A313864593" + +/* + * Arg0: UUID + * Arg1: Revision ID (set to 1) + * Arg2: Function Index + * 0: Query command implemented + * 1: Query force power enable state + * 2: Set force power state + * Arg3: A package containing parameters for the function specified + * by the UUID, revision ID and function index. + */ + +static void usb4_retimer_cb_standard_query(void *arg) +{ + /* + * ToInteger (Arg1, Local2) + * If (Local2 == 1) { + * Return(Buffer() {0x07}) + * } + * Return (Buffer() {0x01}) + */ + acpigen_write_to_integer(ARG1_OP, LOCAL2_OP); + + /* Revision 1 supports 2 Functions beyond the standard query */ + acpigen_write_if_lequal_op_int(LOCAL2_OP, 1); + acpigen_write_return_singleton_buffer(0x07); + acpigen_pop_len(); /* If */ + + /* Other revisions support no additional functions */ + acpigen_write_return_singleton_buffer(0); +} + +static void usb4_retimer_cb_get_power_state(void *arg) +{ + struct acpi_gpio *power_gpio = arg; + + /* + * // Read power gpio into Local0 + * Store (\_SB.PCI0.GTXS (power_gpio), Local0) + * Return (Local0) + */ + acpigen_get_tx_gpio(power_gpio); + acpigen_write_return_op(LOCAL0_OP); +} + +static void usb4_retimer_cb_set_power_state(void *arg) +{ + struct acpi_gpio *power_gpio = arg; + + /* + * // Get argument for on/off from Arg3[0] + * Local0 = DeRefOf (Arg3[0]) + */ + acpigen_get_package_op_element(ARG3_OP, 0, LOCAL0_OP); + + /* + * If (Local0 == 0) { + * // Turn power off + * \_SB.PCI0.CTXS (power_gpio) + * } + */ + acpigen_write_if_lequal_op_int(LOCAL0_OP, 0); + acpigen_disable_tx_gpio(power_gpio); + acpigen_pop_len(); /* If */ + + /* + * Else { + * // Turn power on + * \_SB.PCI0.STXS (power_gpio) + * } + */ + acpigen_write_else(); + acpigen_enable_tx_gpio(power_gpio); + acpigen_pop_len(); + + /* Return (Zero) */ + acpigen_write_return_integer(0); +} + +static void (*usb4_retimer_callbacks[3])(void *) = { + usb4_retimer_cb_standard_query, /* Function 0 */ + usb4_retimer_cb_get_power_state, /* Function 1 */ + usb4_retimer_cb_set_power_state, /* Function 2 */ +}; + +static void usb4_retimer_fill_ssdt(const struct device *dev) +{ + const struct drivers_intel_usb4_retimer_config *config = dev->chip_info; + const char *scope = acpi_device_scope(dev); + + if (!dev->enabled || !scope || !config) + return; + + if (!config->power_gpio.pin_count) { + printk(BIOS_ERR, "%s: Power GPIO required for %s\n", __func__, dev_path(dev)); + return; + } + + /* Write the _DSM that toggles power with provided GPIO. */ + acpigen_write_scope(scope); + acpigen_write_dsm(INTEL_USB4_RETIMER_DSM_UUID, usb4_retimer_callbacks, + ARRAY_SIZE(usb4_retimer_callbacks), (void *)&config->power_gpio); + acpigen_pop_len(); /* Scope */ + + printk(BIOS_INFO, "%s: %s at %s\n", acpi_device_path(dev), dev->chip_ops->name, + dev_path(dev)); +} + +static struct device_operations usb4_retimer_dev_ops = { + .read_resources = noop_read_resources, + .set_resources = noop_set_resources, + .acpi_fill_ssdt = usb4_retimer_fill_ssdt, +}; + +static void usb4_retimer_enable(struct device *dev) +{ + dev->ops = &usb4_retimer_dev_ops; +} + +struct chip_operations drivers_intel_usb4_retimer_ops = { + CHIP_NAME("Intel USB4 Retimer") + .enable_dev = usb4_retimer_enable +}; |