On 10/28/2016 12:43 PM, Mathieu Poirier wrote: > On 27 October 2016 at 15:49, Andrew F. Davis <afd@xxxxxx> wrote: >> Some TI Keystone family of SoCs contain a system controller (like the >> Power Management Micro Controller (PMMC) on K2G SoCs) that manage the >> low-level device control (like clocks, resets etc) for the various >> hardware modules present on the SoC. These device control operations >> are provided to the host processor OS through a communication protocol >> called the TI System Control Interface (TI SCI) protocol. >> >> This patch adds a reset driver that communicates to the system >> controller over the TI SCI protocol for performing reset management >> of various devices present on the SoC. Various reset functionalities >> are achieved by the means of different TI SCI device operations >> provided by the TI SCI framework. >> >> Signed-off-by: Andrew F. Davis <afd@xxxxxx> >> [s-anna@xxxxxx: documentation changes, revised commit message] >> Signed-off-by: Suman Anna <s-anna@xxxxxx> >> Signed-off-by: Nishanth Menon <nm@xxxxxx> >> --- >> MAINTAINERS | 1 + >> drivers/reset/Kconfig | 9 ++ >> drivers/reset/Makefile | 1 + >> drivers/reset/reset-ti-sci.c | 262 +++++++++++++++++++++++++++++++++++++++++++ >> 4 files changed, 273 insertions(+) >> create mode 100644 drivers/reset/reset-ti-sci.c >> >> diff --git a/MAINTAINERS b/MAINTAINERS >> index accf991..b93d91a 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -11901,6 +11901,7 @@ F: include/dt-bindings/clock/k2g.h >> F: drivers/clk/keystone/sci-clk.c >> F: Documentation/devicetree/bindings/reset/ti,sci-reset.txt >> F: include/dt-bindings/reset/k2g.h >> +F: drivers/reset/reset-ti-sci.c >> >> THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER >> M: Hans Verkuil <hverkuil@xxxxxxxxx> >> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig >> index 06d9fa2..4c21c9d 100644 >> --- a/drivers/reset/Kconfig >> +++ b/drivers/reset/Kconfig >> @@ -66,6 +66,15 @@ config RESET_SUNXI >> help >> This enables the reset driver for Allwinner SoCs. >> >> +config RESET_TI_SCI >> + tristate "TI System Control Interface (TI-SCI) reset driver" >> + depends on RESET_CONTROLLER >> + depends on TI_SCI_PROTOCOL >> + help >> + This enables the reset driver support over TI System Control Interface >> + available on some new TI SoCs. If you wish to use reset resources >> + managed by the TI System Controller, say Y here. Otherwise, say N. >> + >> config TI_SYSCON_RESET >> tristate "TI SYSCON Reset Driver" >> depends on HAS_IOMEM >> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile >> index bbe7026..36321f2 100644 >> --- a/drivers/reset/Makefile >> +++ b/drivers/reset/Makefile >> @@ -10,6 +10,7 @@ obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o >> obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o >> obj-$(CONFIG_RESET_STM32) += reset-stm32.o >> obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o >> +obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o >> obj-$(CONFIG_TI_SYSCON_RESET) += reset-ti-syscon.o >> obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o >> obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o >> diff --git a/drivers/reset/reset-ti-sci.c b/drivers/reset/reset-ti-sci.c >> new file mode 100644 >> index 0000000..42ccf12 >> --- /dev/null >> +++ b/drivers/reset/reset-ti-sci.c >> @@ -0,0 +1,262 @@ >> +/* >> + * Texas Instrument's System Control Interface (TI-SCI) reset driver >> + * >> + * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/ >> + * Andrew F. Davis <afd@xxxxxx> >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any >> + * kind, whether express or implied; without even the implied warranty >> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + */ >> + >> +#include <linux/idr.h> >> +#include <linux/module.h> >> +#include <linux/of.h> >> +#include <linux/platform_device.h> >> +#include <linux/reset-controller.h> >> +#include <linux/soc/ti/ti_sci_protocol.h> >> + >> +/** >> + * struct ti_sci_reset_control - reset control structure >> + * @dev_id: SoC-specific device identifier >> + * @reset_mask: reset mask to use for toggling reset >> + */ >> +struct ti_sci_reset_control { >> + u32 dev_id; >> + u32 reset_mask; >> +}; >> + >> +/** >> + * struct ti_sci_reset_data - reset controller information structure >> + * @rcdev: reset controller entity >> + * @dev: reset controller device pointer >> + * @sci: TI SCI handle used for communication with system controller >> + * @idr: idr structure for mapping ids to reset control structures >> + */ >> +struct ti_sci_reset_data { >> + struct reset_controller_dev rcdev; >> + struct device *dev; >> + const struct ti_sci_handle *sci; >> + struct idr idr; >> +}; >> + >> +#define to_ti_sci_reset_data(p) \ >> + container_of((p), struct ti_sci_reset_data, rcdev) >> + >> +/** >> + * ti_sci_reset_set() - program a device's reset >> + * @rcdev: reset controller entity >> + * @id: ID of the reset to toggle >> + * @assert: boolean flag to indicate assert or deassert >> + * >> + * This is a common internal function used to assert or deassert a device's >> + * reset using the TI SCI protocol. The device's reset is asserted if the >> + * @assert argument is true, or deasserted if @assert argument is false. >> + * The mechanism itself is a read-modify-write procedure, the current device >> + * reset register is read using a TI SCI device operation, the new value is >> + * set or un-set using the reset's mask, and the new reset value written by >> + * using another TI SCI device operation. >> + * >> + * Return: 0 for successful request, else a corresponding error value >> + */ >> +static int ti_sci_reset_set(struct reset_controller_dev *rcdev, >> + unsigned long id, bool assert) >> +{ >> + struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); >> + const struct ti_sci_handle *sci = data->sci; >> + const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops; >> + struct ti_sci_reset_control *control; >> + u32 reset_state; >> + int ret; >> + >> + control = idr_find(&data->idr, id); >> + if (!control) >> + return -EINVAL; >> + >> + ret = dev_ops->get_device_resets(sci, control->dev_id, >> + &reset_state); >> + if (ret) >> + return ret; >> + >> + if (assert) >> + reset_state |= control->reset_mask; >> + else >> + reset_state &= ~control->reset_mask; >> + >> + return dev_ops->set_device_resets(sci, control->dev_id, >> + reset_state); >> +} >> + >> +/** >> + * ti_sci_reset_assert() - assert device reset >> + * @rcdev: reset controller entity >> + * @id: ID of the reset to be asserted >> + * >> + * This function implements the reset driver op to assert a device's reset >> + * using the TI SCI protocol. This invokes the function ti_sci_reset_set() >> + * with the corresponding parameters as passed in, but with the @assert >> + * argument set to true for asserting the reset. >> + * >> + * Return: 0 for successful request, else a corresponding error value >> + */ >> +static int ti_sci_reset_assert(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + return ti_sci_reset_set(rcdev, id, true); >> +} >> + >> +/** >> + * ti_sci_reset_deassert() - deassert device reset >> + * @rcdev: reset controller entity >> + * @id: ID of the reset to be deasserted >> + * >> + * This function implements the reset driver op to deassert a device's reset >> + * using the TI SCI protocol. This invokes the function ti_sci_reset_set() >> + * with the corresponding parameters as passed in, but with the @assert >> + * argument set to false for deasserting the reset. >> + * >> + * Return: 0 for successful request, else a corresponding error value >> + */ >> +static int ti_sci_reset_deassert(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + return ti_sci_reset_set(rcdev, id, false); >> +} >> + >> +/** >> + * ti_sci_reset_status() - check device reset status >> + * @rcdev: reset controller entity >> + * @id: ID of reset to be checked >> + * >> + * This function implements the reset driver op to return the status of a >> + * device's reset using the TI SCI protocol. The reset register value is read >> + * by invoking the TI SCI device opertation .get_device_resets(), and the >> + * status of the specific reset is extracted and returned using this reset's >> + * reset mask. >> + * >> + * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted >> + */ >> +static int ti_sci_reset_status(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); >> + const struct ti_sci_handle *sci = data->sci; >> + const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops; >> + struct ti_sci_reset_control *control; >> + u32 reset_state; >> + int ret; >> + >> + control = idr_find(&data->idr, id); >> + if (!control) >> + return -EINVAL; >> + >> + ret = dev_ops->get_device_resets(sci, control->dev_id, >> + &reset_state); >> + if (ret) >> + return ret; >> + >> + return reset_state & control->reset_mask; >> +} >> + >> +static struct reset_control_ops ti_sci_reset_ops = { >> + .assert = ti_sci_reset_assert, >> + .deassert = ti_sci_reset_deassert, >> + .status = ti_sci_reset_status, >> +}; >> + >> +/** >> + * ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID >> + * @rcdev: reset controller entity >> + * @reset_spec: OF reset argument specifier >> + * >> + * This function performs the translation of the reset argument specifier >> + * values defined in a reset consumer device node. The function allocates a >> + * reset control structure for that device reset, and will be used by the >> + * driver for performing any reset functions on that reset. An idr structure >> + * is allocated and used to map to the reset control structure. This idr >> + * is used by the driver to do reset lookups. >> + * >> + * Return: 0 for successful request, else a corresponding error value >> + */ >> +static int ti_sci_reset_of_xlate(struct reset_controller_dev *rcdev, >> + const struct of_phandle_args *reset_spec) >> +{ >> + struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); >> + struct ti_sci_reset_control *control; >> + >> + if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) >> + return -EINVAL; >> + >> + control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL); >> + if (!control) >> + return -ENOMEM; >> + >> + control->dev_id = reset_spec->args[0]; >> + control->reset_mask = reset_spec->args[1]; >> + >> + return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL); >> +} >> + >> +static const struct of_device_id ti_sci_reset_of_match[] = { >> + { .compatible = "ti,sci-reset", }, >> + { /* sentinel */ }, >> +}; >> +MODULE_DEVICE_TABLE(of, ti_sci_reset_of_match); >> + >> +static int ti_sci_reset_probe(struct platform_device *pdev) >> +{ >> + struct ti_sci_reset_data *data; >> + >> + if (!pdev->dev.of_node) >> + return -ENODEV; >> + >> + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); >> + if (!data) >> + return -ENOMEM; >> + >> + data->sci = devm_ti_sci_get_handle(&pdev->dev); >> + if (IS_ERR(data->sci)) >> + return PTR_ERR(data->sci); >> + >> + data->rcdev.ops = &ti_sci_reset_ops; >> + data->rcdev.owner = THIS_MODULE; >> + data->rcdev.of_node = pdev->dev.of_node; >> + data->rcdev.of_reset_n_cells = 2; >> + data->rcdev.of_xlate = ti_sci_reset_of_xlate; >> + data->dev = &pdev->dev; >> + idr_init(&data->idr); > > Hello Andrew, > > For my own education, is there a specific reason to use a struct idr > as opposed to keeping a pointer to a struct ti_sci_reset_control in > truct ti_sci_reset_data? I'm not opposed to the way you've done > things but simply keeping a pointer sound more intuitive to me. > > Thanks, > Mathieu > Hi Mathieu, There is one ti_sci_reset_data per reset controller, and each reset controller can have many resets (each described by a ti_sci_reset_control instance). When a consumer requests a reset we need to both generate a unique ID to give back to the consumer to reference this reset and then internally map this ID to a new ti_sci_reset_control instance for later look-up when the consumer uses this reset, IDR does both of these for us. Thanks, Andrew >> + >> + platform_set_drvdata(pdev, data); >> + >> + return reset_controller_register(&data->rcdev); >> +} >> + >> +static int ti_sci_reset_remove(struct platform_device *pdev) >> +{ >> + struct ti_sci_reset_data *data = platform_get_drvdata(pdev); >> + >> + reset_controller_unregister(&data->rcdev); >> + >> + idr_destroy(&data->idr); >> + >> + return 0; >> +} >> + >> +static struct platform_driver ti_sci_reset_driver = { >> + .probe = ti_sci_reset_probe, >> + .remove = ti_sci_reset_remove, >> + .driver = { >> + .name = "ti-sci-reset", >> + .of_match_table = ti_sci_reset_of_match, >> + }, >> +}; >> +module_platform_driver(ti_sci_reset_driver); >> + >> +MODULE_AUTHOR("Andrew F. Davis <afd@xxxxxx>"); >> +MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver"); >> +MODULE_LICENSE("GPL v2"); >> -- >> 2.10.1 >> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
