From be3035e3627d2570de4c2c612ecd095968986437 Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Fri, 25 May 2018 21:24:34 +0200 Subject: ARM: bcm2835: Add GET_THROTTLED firmware property Recent Raspberry Pi firmware provides a mailbox property to detect under-voltage conditions. Here is the current definition. The u32 value returned by the firmware is divided into 2 parts: - lower 16-bits are the live value - upper 16-bits are the history or sticky value Bits: 0: undervoltage 1: arm frequency capped 2: currently throttled 16: undervoltage has occurred 17: arm frequency capped has occurred 18: throttling has occurred Signed-off-by: Stefan Wahren Signed-off-by: Eric Anholt Reviewed-by: Eric Anholt --- include/soc/bcm2835/raspberrypi-firmware.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index 8ee8991aa099..c4a5c9e9fb47 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -75,6 +75,7 @@ enum rpi_firmware_property_tag { RPI_FIRMWARE_GET_EDID_BLOCK = 0x00030020, RPI_FIRMWARE_GET_CUSTOMER_OTP = 0x00030021, RPI_FIRMWARE_GET_DOMAIN_STATE = 0x00030030, + RPI_FIRMWARE_GET_THROTTLED = 0x00030046, RPI_FIRMWARE_SET_CLOCK_STATE = 0x00038001, RPI_FIRMWARE_SET_CLOCK_RATE = 0x00038002, RPI_FIRMWARE_SET_VOLTAGE = 0x00038003, -- cgit v1.2.3 From 74d1e007915fab590f8be9dc647b19511260210c Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Fri, 25 May 2018 21:24:35 +0200 Subject: hwmon: Add support for RPi voltage sensor MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently there is no easy way to detect undervoltage conditions on a remote Raspberry Pi. This hwmon driver retrieves the state of the undervoltage sensor via mailbox interface. The handling based on Noralf's modifications to the downstream firmware driver. In case of an undervoltage condition only an entry is written to the kernel log. CC: "Noralf Trønnes" Signed-off-by: Stefan Wahren Signed-off-by: Eric Anholt Acked-by: Guenter Roeck --- Documentation/hwmon/raspberrypi-hwmon | 22 +++++ drivers/hwmon/Kconfig | 10 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/raspberrypi-hwmon.c | 166 ++++++++++++++++++++++++++++++++++ 4 files changed, 199 insertions(+) create mode 100644 Documentation/hwmon/raspberrypi-hwmon create mode 100644 drivers/hwmon/raspberrypi-hwmon.c diff --git a/Documentation/hwmon/raspberrypi-hwmon b/Documentation/hwmon/raspberrypi-hwmon new file mode 100644 index 000000000000..3c92e2cb52d6 --- /dev/null +++ b/Documentation/hwmon/raspberrypi-hwmon @@ -0,0 +1,22 @@ +Kernel driver raspberrypi-hwmon +=============================== + +Supported boards: + * Raspberry Pi A+ (via GPIO on SoC) + * Raspberry Pi B+ (via GPIO on SoC) + * Raspberry Pi 2 B (via GPIO on SoC) + * Raspberry Pi 3 B (via GPIO on port expander) + * Raspberry Pi 3 B+ (via PMIC) + +Author: Stefan Wahren + +Description +----------- + +This driver periodically polls a mailbox property of the VC4 firmware to detect +undervoltage conditions. + +Sysfs entries +------------- + +in0_lcrit_alarm Undervoltage alarm diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index f10840ad465c..195154178aff 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN This driver can also be built as a module. If so, the module will be called pwm-fan. +config SENSORS_RASPBERRYPI_HWMON + tristate "Raspberry Pi voltage monitor" + depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE) + help + If you say yes here you get support for voltage sensor on the + Raspberry Pi. + + This driver can also be built as a module. If so, the module + will be called raspberrypi-hwmon. + config SENSORS_SHT15 tristate "Sensiron humidity and temperature sensors. SHT15 and compat." depends on GPIOLIB || COMPILE_TEST diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index e7d52a36e6c4..a9297703fd6e 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) += pc87427.o obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o +obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c new file mode 100644 index 000000000000..fb4e4a6bb1f6 --- /dev/null +++ b/drivers/hwmon/raspberrypi-hwmon.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Raspberry Pi voltage sensor driver + * + * Based on firmware/raspberrypi.c by Noralf Trønnes + * + * Copyright (C) 2018 Stefan Wahren + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#define UNDERVOLTAGE_STICKY_BIT BIT(16) + +struct rpi_hwmon_data { + struct device *hwmon_dev; + struct rpi_firmware *fw; + u32 last_throttled; + struct delayed_work get_values_poll_work; +}; + +static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data) +{ + u32 new_uv, old_uv, value; + int ret; + + /* Request firmware to clear sticky bits */ + value = 0xffff; + + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, + &value, sizeof(value)); + if (ret) { + dev_err_once(data->hwmon_dev, "Failed to get throttled (%d)\n", + ret); + return; + } + + new_uv = value & UNDERVOLTAGE_STICKY_BIT; + old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT; + data->last_throttled = value; + + if (new_uv == old_uv) + return; + + if (new_uv) + dev_crit(data->hwmon_dev, "Undervoltage detected!\n"); + else + dev_info(data->hwmon_dev, "Voltage normalised\n"); + + sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm"); +} + +static void get_values_poll(struct work_struct *work) +{ + struct rpi_hwmon_data *data; + + data = container_of(work, struct rpi_hwmon_data, + get_values_poll_work.work); + + rpi_firmware_get_throttled(data); + + /* + * We can't run faster than the sticky shift (100ms) since we get + * flipping in the sticky bits that are cleared. + */ + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); +} + +static int rpi_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct rpi_hwmon_data *data = dev_get_drvdata(dev); + + *val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); + return 0; +} + +static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + return 0444; +} + +static const u32 rpi_in_config[] = { + HWMON_I_LCRIT_ALARM, + 0 +}; + +static const struct hwmon_channel_info rpi_in = { + .type = hwmon_in, + .config = rpi_in_config, +}; + +static const struct hwmon_channel_info *rpi_info[] = { + &rpi_in, + NULL +}; + +static const struct hwmon_ops rpi_hwmon_ops = { + .is_visible = rpi_is_visible, + .read = rpi_read, +}; + +static const struct hwmon_chip_info rpi_chip_info = { + .ops = &rpi_hwmon_ops, + .info = rpi_info, +}; + +static int rpi_hwmon_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct rpi_hwmon_data *data; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + /* Parent driver assure that firmware is correct */ + data->fw = dev_get_drvdata(dev->parent); + + /* Init throttled */ + ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, + &data->last_throttled, + sizeof(data->last_throttled)); + + data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt", + data, + &rpi_chip_info, + NULL); + + INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll); + platform_set_drvdata(pdev, data); + + if (!PTR_ERR_OR_ZERO(data->hwmon_dev)) + schedule_delayed_work(&data->get_values_poll_work, 2 * HZ); + + return PTR_ERR_OR_ZERO(data->hwmon_dev); +} + +static int rpi_hwmon_remove(struct platform_device *pdev) +{ + struct rpi_hwmon_data *data = platform_get_drvdata(pdev); + + cancel_delayed_work_sync(&data->get_values_poll_work); + + return 0; +} + +static struct platform_driver rpi_hwmon_driver = { + .probe = rpi_hwmon_probe, + .remove = rpi_hwmon_remove, + .driver = { + .name = "raspberrypi-hwmon", + }, +}; +module_platform_driver(rpi_hwmon_driver); + +MODULE_AUTHOR("Stefan Wahren "); +MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3 From 70eea1bbb5561154e62b322904b685acb0e52d3e Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Fri, 25 May 2018 21:24:36 +0200 Subject: firmware: raspberrypi: Register hwmon driver Since the raspberrypi-hwmon driver is tied to the VC4 firmware instead of particular hardware its registration should be in the firmware driver. Signed-off-by: Stefan Wahren Signed-off-by: Eric Anholt --- drivers/firmware/raspberrypi.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 6692888f04cf..0602626bf72d 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -21,6 +21,8 @@ #define MBOX_DATA28(msg) ((msg) & ~0xf) #define MBOX_CHAN_PROPERTY 8 +static struct platform_device *rpi_hwmon; + struct rpi_firmware { struct mbox_client cl; struct mbox_chan *chan; /* The property channel. */ @@ -183,6 +185,20 @@ rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) } } +static void +rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) +{ + u32 packet; + int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, + &packet, sizeof(packet)); + + if (ret) + return; + + rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", + -1, NULL, 0); +} + static int rpi_firmware_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -209,6 +225,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) platform_set_drvdata(pdev, fw); rpi_firmware_print_firmware_revision(fw); + rpi_register_hwmon_driver(dev, fw); return 0; } @@ -217,6 +234,8 @@ static int rpi_firmware_remove(struct platform_device *pdev) { struct rpi_firmware *fw = platform_get_drvdata(pdev); + platform_device_unregister(rpi_hwmon); + rpi_hwmon = NULL; mbox_free_channel(fw->chan); return 0; -- cgit v1.2.3 From a1547e0bca519b92b09ac5530c6accb7c3f69d1a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 29 Jun 2018 11:44:50 -0700 Subject: firmware: raspberrypi: Remove VLA usage In the quest to remove all stack VLA usage from the kernel[1], this removes the VLA in favor of a maximum size and adds a sanity check. Existing callers of the firmware interface never need more than 24 bytes (struct gpio_set_config). This chooses 32 just to stay ahead of future growth. v2: Fix the length passed to rpi_firmware_property_list (by anholt, acked by Kees). [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook Signed-off-by: Eric Anholt Reviewed-by: Eric Anholt --- drivers/firmware/raspberrypi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 0602626bf72d..a200a2174611 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -21,6 +21,8 @@ #define MBOX_DATA28(msg) ((msg) & ~0xf) #define MBOX_CHAN_PROPERTY 8 +#define MAX_RPI_FW_PROP_BUF_SIZE 32 + static struct platform_device *rpi_hwmon; struct rpi_firmware { @@ -145,18 +147,22 @@ int rpi_firmware_property(struct rpi_firmware *fw, /* Single tags are very small (generally 8 bytes), so the * stack should be safe. */ - u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)]; + u8 data[sizeof(struct rpi_firmware_property_tag_header) + + MAX_RPI_FW_PROP_BUF_SIZE]; struct rpi_firmware_property_tag_header *header = (struct rpi_firmware_property_tag_header *)data; int ret; + if (WARN_ON(buf_size > sizeof(data) - sizeof(*header))) + return -EINVAL; + header->tag = tag; header->buf_size = buf_size; header->req_resp_size = 0; memcpy(data + sizeof(struct rpi_firmware_property_tag_header), tag_data, buf_size); - ret = rpi_firmware_property_list(fw, &data, sizeof(data)); + ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header)); memcpy(tag_data, data + sizeof(struct rpi_firmware_property_tag_header), buf_size); -- cgit v1.2.3