| Message ID | 20200612171334.26385-3-nsaenzjulienne@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Raspberry Pi 4 USB firmware initialization rework | expand |
Hi Nicolas, On Fri, 2020-06-12 at 19:13 +0200, Nicolas Saenz Julienne wrote: > Raspberry Pi 4's co-processor controls some of the board's HW > initialization process, but it's up to Linux to trigger it when > relevant. Introduce a reset controller capable of interfacing with > RPi4's co-processor that models these firmware initialization routines as > reset lines. > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> If there is a good reason for the single DT specified reset id, I can pick up patches 1 and 2. If you change the dts patch 4 to use a number instead of the reset id define for now, there wouldn't even be a dependency between these reset and dts patches. regards Philipp
On Wed, 2020-06-17 at 12:02 +0200, Philipp Zabel wrote: > Hi Nicolas, > > On Fri, 2020-06-12 at 19:13 +0200, Nicolas Saenz Julienne wrote: > > Raspberry Pi 4's co-processor controls some of the board's HW > > initialization process, but it's up to Linux to trigger it when > > relevant. Introduce a reset controller capable of interfacing with > > RPi4's co-processor that models these firmware initialization routines as > > reset lines. > > > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Thanks! > If there is a good reason for the single DT specified reset id, I can > pick up patches 1 and 2. The idea here is to make sure we're reasonably covered against further changes in firmware. If we define constraints too narrow it can be a pain to support new features without breaking backwards compatibility in dt. > If you change the dts patch 4 to use a number instead of the reset id > define for now, there wouldn't even be a dependency between these reset > and dts patches. I was under the impression that having an explicit definition was nice to have. What's troubling about creating the dependency? Regards, Nicolas
On Wed, 2020-06-17 at 12:44 +0200, Nicolas Saenz Julienne wrote: > On Wed, 2020-06-17 at 12:02 +0200, Philipp Zabel wrote: > > Hi Nicolas, > > > > On Fri, 2020-06-12 at 19:13 +0200, Nicolas Saenz Julienne wrote: > > > Raspberry Pi 4's co-processor controls some of the board's HW > > > initialization process, but it's up to Linux to trigger it when > > > relevant. Introduce a reset controller capable of interfacing with > > > RPi4's co-processor that models these firmware initialization routines as > > > reset lines. > > > > > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> > > > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> > > Thanks! > > > If there is a good reason for the single DT specified reset id, I can > > pick up patches 1 and 2. > > The idea here is to make sure we're reasonably covered against further changes > in firmware. If we define constraints too narrow it can be a pain to support > new features without breaking backwards compatibility in dt. Ok. > > If you change the dts patch 4 to use a number instead of the reset id > > define for now, there wouldn't even be a dependency between these reset > > and dts patches. > > I was under the impression that having an explicit definition was nice to have. > What's troubling about creating the dependency? Just that the last patch has to wait for the reset patches to be merged before it can be applied. regards Philipp
On Fri, 2020-06-26 at 12:43 +0200, Philipp Zabel wrote: > On Wed, 2020-06-17 at 12:44 +0200, Nicolas Saenz Julienne wrote: > > On Wed, 2020-06-17 at 12:02 +0200, Philipp Zabel wrote: > > > Hi Nicolas, > > > > > > On Fri, 2020-06-12 at 19:13 +0200, Nicolas Saenz Julienne wrote: > > > > Raspberry Pi 4's co-processor controls some of the board's HW > > > > initialization process, but it's up to Linux to trigger it when > > > > relevant. Introduce a reset controller capable of interfacing with > > > > RPi4's co-processor that models these firmware initialization routines > > > > as > > > > reset lines. > > > > > > > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > > > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> > > > > > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> > > > > Thanks! > > > > > If there is a good reason for the single DT specified reset id, I can > > > pick up patches 1 and 2. > > > > The idea here is to make sure we're reasonably covered against further > > changes > > in firmware. If we define constraints too narrow it can be a pain to support > > new features without breaking backwards compatibility in dt. > > Ok. > > > > If you change the dts patch 4 to use a number instead of the reset id > > > define for now, there wouldn't even be a dependency between these reset > > > and dts patches. > > > > I was under the impression that having an explicit definition was nice to > > have. > > What's troubling about creating the dependency? > > Just that the last patch has to wait for the reset patches to be merged > before it can be applied. TBH there is no hurry, this only provides a better design on something that's already available upstream. USB works on RPi4, so I don't mind if this gets delayed a release. Regards, Nicolas
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index d9efbfd29646..97e848740e13 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -140,6 +140,17 @@ config RESET_QCOM_PDC to control reset signals provided by PDC for Modem, Compute, Display, GPU, Debug, AOP, Sensors, Audio, SP and APPS. +config RESET_RASPBERRYPI + tristate "Raspberry Pi 4 Firmware Reset Driver" + depends on RASPBERRYPI_FIRMWARE || (RASPBERRYPI_FIRMWARE=n && COMPILE_TEST) + default USB_XHCI_PCI + help + Raspberry Pi 4's co-processor controls some of the board's HW + initialization process, but it's up to Linux to trigger it when + relevant. This driver provides a reset controller capable of + interfacing with RPi4's co-processor and model these firmware + initialization routines as reset lines. + config RESET_SCMI tristate "Reset driver controlled via ARM SCMI interface" depends on ARM_SCMI_PROTOCOL || COMPILE_TEST diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 249ed357c997..16947610cc3b 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o +obj-$(CONFIG_RESET_RASPBERRYPI) += reset-raspberrypi.o obj-$(CONFIG_RESET_SCMI) += reset-scmi.o obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o diff --git a/drivers/reset/reset-raspberrypi.c b/drivers/reset/reset-raspberrypi.c new file mode 100644 index 000000000000..91aa29f893b9 --- /dev/null +++ b/drivers/reset/reset-raspberrypi.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Raspberry Pi 4 firmware reset driver + * + * Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de> + */ +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> +#include <soc/bcm2835/raspberrypi-firmware.h> +#include <dt-bindings/reset/raspberrypi,firmware-reset.h> + +struct rpi_reset { + struct reset_controller_dev rcdev; + struct rpi_firmware *fw; +}; + +static inline struct rpi_reset *to_rpi(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct rpi_reset, rcdev); +} + +static int rpi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id) +{ + struct rpi_reset *priv = to_rpi(rcdev); + u32 dev_addr; + int ret; + + switch (id) { + case RASPBERRYPI_FIRMWARE_RESET_ID_USB: + /* + * The Raspberry Pi 4 gets its USB functionality from VL805, a + * PCIe chip that implements xHCI. After a PCI reset, VL805's + * firmware may either be loaded directly from an EEPROM or, if + * not present, by the SoC's co-processor, VideoCore. rpi's + * VideoCore OS contains both the non public firmware load + * logic and the VL805 firmware blob. This triggers the + * aforementioned process. + * + * The pci device address is expected is expected by the + * firmware encoded like this: + * + * PCI_BUS << 20 | PCI_SLOT << 15 | PCI_FUNC << 12 + * + * But since rpi's PCIe is hardwired, we know the address in + * advance. + */ + dev_addr = 0x100000; + ret = rpi_firmware_property(priv->fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET, + &dev_addr, sizeof(dev_addr)); + if (ret) + return ret; + + /* Wait for vl805 to startup */ + usleep_range(200, 1000); + break; + + default: + return -EINVAL; + } + + return 0; +} + +static const struct reset_control_ops rpi_reset_ops = { + .reset = rpi_reset_reset, +}; + +static int rpi_reset_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *fw_node; + struct rpi_firmware *fw; + struct rpi_reset *priv; + + fw_node = of_get_parent(dev->of_node); + if (!fw_node) { + dev_err(dev, "Missing firmware node\n"); + return -ENOENT; + } + + fw = rpi_firmware_get(fw_node); + of_node_put(fw_node); + if (!fw) + return -EPROBE_DEFER; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + dev_set_drvdata(dev, priv); + + priv->fw = fw; + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.nr_resets = RASPBERRYPI_FIRMWARE_RESET_NUM_IDS; + priv->rcdev.ops = &rpi_reset_ops; + priv->rcdev.of_node = dev->of_node; + + return devm_reset_controller_register(dev, &priv->rcdev); +} + +static const struct of_device_id rpi_reset_of_match[] = { + { .compatible = "raspberrypi,firmware-reset" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rpi_reset_of_match); + +static struct platform_driver rpi_reset_driver = { + .probe = rpi_reset_probe, + .driver = { + .name = "raspberrypi-reset", + .of_match_table = rpi_reset_of_match, + }, +}; +module_platform_driver(rpi_reset_driver); + +MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>"); +MODULE_DESCRIPTION("Raspberry Pi 4 firmware reset driver"); +MODULE_LICENSE("GPL");