From patchwork Mon Jun 10 11:26:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 1945843 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=sang-engineering.com header.i=@sang-engineering.com header.a=rsa-sha256 header.s=k1 header.b=Tfaqv0ci; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2604:1380:40f1:3f00::1; helo=sy.mirrors.kernel.org; envelope-from=linux-gpio+bounces-7306-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org [IPv6:2604:1380:40f1:3f00::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4VyV0Y4L7Fz20Tk for ; Mon, 10 Jun 2024 21:27:57 +1000 (AEST) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id 74448B219E8 for ; Mon, 10 Jun 2024 11:27:55 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2EB457F483; Mon, 10 Jun 2024 11:27:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="Tfaqv0ci" X-Original-To: linux-gpio@vger.kernel.org Received: from mail.zeus03.de (www.zeus03.de [194.117.254.33]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E6E37D08F for ; Mon, 10 Jun 2024 11:27:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718018830; cv=none; b=BFsq372gH+axW5vu6MDObNgBAb3dpQcUTJRWuOjEgLJOMkqup9LhtMfgJInF2EJuqQJ31lKXpzmxjRPcdjq/vPGFpPLZCibnzmRakc+A+b13K09VxAXB5WTttXJ5r/n7unnP0ItKe7U1v+5FyV5cgMpndu5xXxqSlGgOOzRXquU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718018830; c=relaxed/simple; bh=COYNIvHh+TAKN5LJprwZuaZwrVt/DES5eyZTvFnXJfE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hAzzzWqVLal9uNDEBDnMexpRnsuYGwMjP4zyEwX/TRDpNjhBYfe9XJr51rqqrCKG+6o+YwFIVWSG8egYZtzQa3VnuXLMC9JRbsI8YjuEOkxUWhqSsKYbxtp5ldvn6iYdl8rVNiYBCyq3jumY3MDM6Y3hfNa3wfuecQ2uUpElRdo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=Tfaqv0ci; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; s=k1; bh=8CkfUvJPScSyzamV1AW4w767pk/x2PKUpb9J7tucmOA=; b=Tfaqv0 ciR4scQyUzbk+aAszFAFFqnka290ZBL4ZnOO02PTdzcME/conHBKcLZtbTjmCvXC APpNfFUUn0HOplm/anVzVYC8+fRiJqoc85R8Z0qhaYQ66ZQsQGZEKJzGano3V6Sc i+KGXtHF27j0Mm0RPONn+nCorZQ5BnX35OiaPWuyQz9l0LnD/KyJJLVejUsTQdqH 9uy7aSgbD9Tfb2/tiD+HofqI7488Z2ZFQ2skH/2pwyKCI0sFA1MnaMugQ5rNy/L9 b+oF1phD8uzOeIpAY/8crjOHx66cv2McTSBtYRojHtr4kF0EaO0VngI7i3/KgAYg 6QCXjLGnvBR/yedQ== Received: (qmail 56196 invoked from network); 10 Jun 2024 13:27:03 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 10 Jun 2024 13:27:03 +0200 X-UD-Smtp-Session: l3s3148p1@2q+qbYcaYuQgAwDPXymAAHMyzy0c7Kdl From: Wolfram Sang To: linux-renesas-soc@vger.kernel.org Cc: Wolfram Sang , Jonathan Corbet , Linus Walleij , Bartosz Golaszewski , Kent Gibson , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org Subject: [PATCH v9 1/1] gpio: add sloppy logic analyzer using polling Date: Mon, 10 Jun 2024 13:26:59 +0200 Message-ID: <20240610112700.80819-2-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240610112700.80819-1-wsa+renesas@sang-engineering.com> References: <20240610112700.80819-1-wsa+renesas@sang-engineering.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This is a sloppy logic analyzer using GPIOs. It comes with a script to isolate a CPU for polling. While this is definitely not a production level analyzer, it can be a helpful first view when remote debugging. Read the documentation for details. Signed-off-by: Wolfram Sang --- Changes since v8: * analyzer: gave 'lock' a more descriptive name * script: handles now SI suffixes somewhat, e.g. '2G' * script: add '--list-instances' option * script: add comment why stall_detector gets disabled * script: improvements to help text * script: added '.sh' extension to filename * script, docs: added SPDX license identifiers .../dev-tools/gpio-sloppy-logic-analyzer.rst | 93 +++++ Documentation/dev-tools/index.rst | 1 + drivers/gpio/Kconfig | 17 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sloppy-logic-analyzer.c | 340 ++++++++++++++++++ tools/gpio/gpio-sloppy-logic-analyzer.sh | 246 +++++++++++++ 6 files changed, 698 insertions(+) create mode 100644 Documentation/dev-tools/gpio-sloppy-logic-analyzer.rst create mode 100644 drivers/gpio/gpio-sloppy-logic-analyzer.c create mode 100755 tools/gpio/gpio-sloppy-logic-analyzer.sh diff --git a/Documentation/dev-tools/gpio-sloppy-logic-analyzer.rst b/Documentation/dev-tools/gpio-sloppy-logic-analyzer.rst new file mode 100644 index 000000000000..d69f24c0d9e1 --- /dev/null +++ b/Documentation/dev-tools/gpio-sloppy-logic-analyzer.rst @@ -0,0 +1,93 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================= +Linux Kernel GPIO based sloppy logic analyzer +============================================= + +:Author: Wolfram Sang + +Introduction +============ + +This document briefly describes how to run the GPIO based in-kernel sloppy +logic analyzer running on an isolated CPU. + +The sloppy logic analyzer will utilize a few GPIO lines in input mode on a +system to rapidly sample these digital lines, which will, if the Nyquist +criteria is met, result in a time series log with approximate waveforms as they +appeared on these lines. One way to use it is to analyze external traffic +connected to these GPIO lines with wires (i.e. digital probes), acting as a +common logic analyzer. + +Another feature is to snoop on on-chip peripherals if the I/O cells of these +peripherals can be used in GPIO input mode at the same time as they are being +used as inputs or outputs for the peripheral. That means you could e.g. snoop +I2C traffic without any wiring (if your hardware supports it). In the pin +control subsystem such pin controllers are called "non-strict": a certain pin +can be used with a certain peripheral and as a GPIO input line at the same +time. + +Note that this is a last resort analyzer which can be affected by latencies, +non-deterministic code paths and non-maskable interrupts. It is called 'sloppy' +for a reason. However, for e.g. remote development, it may be useful to get a +first view and aid further debugging. + +Setup +===== + +Your kernel must have CONFIG_DEBUG_FS and CONFIG_CPUSETS enabled. Ideally, your +runtime environment does not utilize cpusets otherwise, then isolation of a CPU +core is easiest. If you do need cpusets, check that helper script for the +sloppy logic analyzer does not interfere with your other settings. + +Tell the kernel which GPIOs are used as probes. For a Device Tree based system, +you need to use the following bindings. Because these bindings are only for +debugging, there is no official schema:: + + i2c-analyzer { + compatible = "gpio-sloppy-logic-analyzer"; + probe-gpios = <&gpio6 21 GPIO_OPEN_DRAIN>, <&gpio6 4 GPIO_OPEN_DRAIN>; + probe-names = "SCL", "SDA"; + }; + +Note that you must provide a name for every GPIO specified. Currently a +maximum of 8 probes are supported. 32 are likely possible but are not +implemented yet. + +Usage +===== + +The logic analyzer is configurable via files in debugfs. However, it is +strongly recommended to not use them directly, but to use the script +``tools/gpio/gpio-sloppy-logic-analyzer``. Besides checking parameters more +extensively, it will isolate the CPU core so you will have the least +disturbance while measuring. + +The script has a help option explaining the parameters. For the above DT +snippet which analyzes an I2C bus at 400kHz on a Renesas Salvator-XS board, the +following settings are used: The isolated CPU shall be CPU1 because it is a big +core in a big.LITTLE setup. Because CPU1 is the default, we don't need a +parameter. The bus speed is 400kHz. So, the sampling theorem says we need to +sample at least at 800kHz. However, falling edges of both signals in an I2C +start condition happen faster, so we need a higher sampling frequency, e.g. +``-s 1500000`` for 1.5MHz. Also, we don't want to sample right away but wait +for a start condition on an idle bus. So, we need to set a trigger to a falling +edge on SDA while SCL stays high, i.e. ``-t 1H+2F``. Last is the duration, let +us assume 15ms here which results in the parameter ``-d 15000``. So, +altogether:: + + gpio-sloppy-logic-analyzer -s 1500000 -t 1H+2F -d 15000 + +Note that the process will return you back to the prompt but a sub-process is +still sampling in the background. Unless this has finished, you will not find a +result file in the current or specified directory. For the above example, we +will then need to trigger I2C communication:: + + i2cdetect -y -r + +Result is a .sr file to be consumed with PulseView or sigrok-cli from the free +`sigrok`_ project. It is a zip file which also contains the binary sample data +which may be consumed by other software. The filename is the logic analyzer +instance name plus a since-epoch timestamp. + +.. _sigrok: https://sigrok.org/ diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index efa49cdc8e2e..6971ed581c08 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -32,6 +32,7 @@ Documentation/dev-tools/testing-overview.rst kunit/index ktap checkuapi + gpio-sloppy-logic-analyzer .. only:: subproject and html diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 1c28a48915bb..44869de5e3fc 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1891,4 +1891,21 @@ config GPIO_SIM endmenu +menu "GPIO hardware hacking tools" + +config GPIO_SLOPPY_LOGIC_ANALYZER + tristate "Sloppy GPIO logic analyzer" + depends on (GPIOLIB || COMPILE_TEST) && CPUSETS && DEBUG_FS && EXPERT + help + This option enables support for a sloppy logic analyzer using polled + GPIOs. Use the 'tools/gpio/gpio-sloppy-logic-analyzer' script with + this driver. The script will make it easier to use and will also + isolate a CPU for the polling task. Note that this is a last resort + analyzer which can be affected by latencies, non-deterministic code + paths, or NMIs. However, for e.g. remote development, it may be useful + to get a first view and aid further debugging. + + If this driver is built as a module it will be called + 'gpio-sloppy-logic-analyzer'. +endmenu endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index e2a53013780e..9889f5b962bf 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -150,6 +150,7 @@ obj-$(CONFIG_GPIO_SIFIVE) += gpio-sifive.o obj-$(CONFIG_GPIO_SIM) += gpio-sim.o obj-$(CONFIG_GPIO_SIOX) += gpio-siox.o obj-$(CONFIG_GPIO_SL28CPLD) += gpio-sl28cpld.o +obj-$(CONFIG_GPIO_SLOPPY_LOGIC_ANALYZER) += gpio-sloppy-logic-analyzer.o obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o obj-$(CONFIG_GPIO_SPEAR_SPICS) += gpio-spear-spics.o obj-$(CONFIG_GPIO_SPRD) += gpio-sprd.o diff --git a/drivers/gpio/gpio-sloppy-logic-analyzer.c b/drivers/gpio/gpio-sloppy-logic-analyzer.c new file mode 100644 index 000000000000..4f61a1852ab0 --- /dev/null +++ b/drivers/gpio/gpio-sloppy-logic-analyzer.c @@ -0,0 +1,340 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Sloppy logic analyzer using GPIOs (to be run on an isolated CPU) + * + * Use the 'gpio-sloppy-logic-analyzer' script in the 'tools/gpio' folder for + * easier usage and further documentation. Note that this is a last resort + * analyzer which can be affected by latencies and non-deterministic code + * paths. However, for e.g. remote development, it may be useful to get a first + * view and aid further debugging. + * + * Copyright (C) Wolfram Sang + * Copyright (C) Renesas Electronics Corporation + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define GPIO_LA_NAME "gpio-sloppy-logic-analyzer" +#define GPIO_LA_DEFAULT_BUF_SIZE SZ_256K +/* can be increased but then we need to extend the u8 buffers */ +#define GPIO_LA_MAX_PROBES 8 +#define GPIO_LA_NUM_TESTS 1024 + +struct gpio_la_poll_priv { + struct mutex blob_lock; /* serialize access to the blob (data) */ + u32 buf_idx; + struct gpio_descs *descs; + unsigned long delay_ns; + unsigned long acq_delay; + struct debugfs_blob_wrapper blob; + struct dentry *debug_dir; + struct dentry *blob_dent; + struct debugfs_blob_wrapper meta; + struct device *dev; + unsigned int trig_len; + u8 *trig_data; +}; + +static struct dentry *gpio_la_poll_debug_dir; + +static __always_inline int gpio_la_get_array(struct gpio_descs *d, unsigned long *sptr) +{ + int ret; + + ret = gpiod_get_array_value(d->ndescs, d->desc, d->info, sptr); + if (ret == 0 && fatal_signal_pending(current)) + ret = -EINTR; + + return ret; +} + +static int fops_capture_set(void *data, u64 val) +{ + struct gpio_la_poll_priv *priv = data; + u8 *la_buf = priv->blob.data; + unsigned long state = 0; /* zeroed because GPIO arrays are bitfields */ + unsigned long delay; + ktime_t start_time; + unsigned int i; + int ret; + + if (!val) + return 0; + + if (!la_buf) + return -ENOMEM; + + if (!priv->delay_ns) + return -EINVAL; + + mutex_lock(&priv->blob_lock); + if (priv->blob_dent) { + debugfs_remove(priv->blob_dent); + priv->blob_dent = NULL; + } + + priv->buf_idx = 0; + + local_irq_disable(); + preempt_disable_notrace(); + + /* Measure delay of reading GPIOs */ + start_time = ktime_get(); + for (i = 0; i < GPIO_LA_NUM_TESTS; i++) { + ret = gpio_la_get_array(priv->descs, &state); + if (ret) + goto out; + } + + priv->acq_delay = ktime_sub(ktime_get(), start_time) / GPIO_LA_NUM_TESTS; + if (priv->delay_ns < priv->acq_delay) { + ret = -ERANGE; + goto out; + } + + delay = priv->delay_ns - priv->acq_delay; + + /* Wait for triggers */ + for (i = 0; i < priv->trig_len; i += 2) { + do { + ret = gpio_la_get_array(priv->descs, &state); + if (ret) + goto out; + + ndelay(delay); + } while ((state & priv->trig_data[i]) != priv->trig_data[i + 1]); + } + + /* With triggers, final state is also the first sample */ + if (priv->trig_len) + la_buf[priv->buf_idx++] = state; + + /* Sample */ + while (priv->buf_idx < priv->blob.size) { + ret = gpio_la_get_array(priv->descs, &state); + if (ret) + goto out; + + la_buf[priv->buf_idx++] = state; + ndelay(delay); + } +out: + preempt_enable_notrace(); + local_irq_enable(); + if (ret) + dev_err(priv->dev, "couldn't read GPIOs: %d\n", ret); + + kfree(priv->trig_data); + priv->trig_data = NULL; + priv->trig_len = 0; + + priv->blob_dent = debugfs_create_blob("sample_data", 0400, priv->debug_dir, &priv->blob); + mutex_unlock(&priv->blob_lock); + + return ret; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_capture, NULL, fops_capture_set, "%llu\n"); + +static int fops_buf_size_get(void *data, u64 *val) +{ + struct gpio_la_poll_priv *priv = data; + + *val = priv->blob.size; + + return 0; +} + +static int fops_buf_size_set(void *data, u64 val) +{ + struct gpio_la_poll_priv *priv = data; + int ret = 0; + void *p; + + if (!val) + return -EINVAL; + + mutex_lock(&priv->blob_lock); + + vfree(priv->blob.data); + p = vzalloc(val); + if (!p) { + val = 0; + ret = -ENOMEM; + } + + priv->blob.data = p; + priv->blob.size = val; + + mutex_unlock(&priv->blob_lock); + return ret; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_buf_size, fops_buf_size_get, fops_buf_size_set, "%llu\n"); + +static int trigger_open(struct inode *inode, struct file *file) +{ + return single_open(file, NULL, inode->i_private); +} + +static ssize_t trigger_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *offset) +{ + struct seq_file *m = file->private_data; + struct gpio_la_poll_priv *priv = m->private; + char *buf; + + /* upper limit is arbitrary but should be less than PAGE_SIZE */ + if (count > 2048 || count & 1) + return -EINVAL; + + buf = memdup_user(ubuf, count); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + priv->trig_data = buf; + priv->trig_len = count; + + return count; +} + +static const struct file_operations fops_trigger = { + .owner = THIS_MODULE, + .open = trigger_open, + .write = trigger_write, + .llseek = no_llseek, + .release = single_release, +}; + +static int gpio_la_poll_probe(struct platform_device *pdev) +{ + struct gpio_la_poll_priv *priv; + struct device *dev = &pdev->dev; + const char *devname = dev_name(dev); + const char *gpio_names[GPIO_LA_MAX_PROBES]; + char *meta = NULL; + unsigned int i, meta_len = 0; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + mutex_init(&priv->blob_lock); + + fops_buf_size_set(priv, GPIO_LA_DEFAULT_BUF_SIZE); + + priv->descs = devm_gpiod_get_array(dev, "probe", GPIOD_IN); + if (IS_ERR(priv->descs)) + return PTR_ERR(priv->descs); + + /* artificial limit to keep 1 byte per sample for now */ + if (priv->descs->ndescs > GPIO_LA_MAX_PROBES) + return -EFBIG; + + ret = device_property_read_string_array(dev, "probe-names", gpio_names, + priv->descs->ndescs); + if (ret >= 0 && ret != priv->descs->ndescs) + ret = -EBADR; + if (ret < 0) + return dev_err_probe(dev, ret, "error naming the GPIOs"); + + for (i = 0; i < priv->descs->ndescs; i++) { + unsigned int add_len; + char *new_meta, *consumer_name; + + if (gpiod_cansleep(priv->descs->desc[i])) + return -EREMOTE; + + consumer_name = kasprintf(GFP_KERNEL, "%s: %s", devname, gpio_names[i]); + if (!consumer_name) + return -ENOMEM; + gpiod_set_consumer_name(priv->descs->desc[i], consumer_name); + kfree(consumer_name); + + /* '10' is length of 'probe00=\n\0' */ + add_len = strlen(gpio_names[i]) + 10; + + new_meta = devm_krealloc(dev, meta, meta_len + add_len, GFP_KERNEL); + if (!new_meta) + return -ENOMEM; + + meta = new_meta; + meta_len += snprintf(meta + meta_len, add_len, "probe%02u=%s\n", + i + 1, gpio_names[i]); + } + + platform_set_drvdata(pdev, priv); + priv->dev = dev; + + priv->meta.data = meta; + priv->meta.size = meta_len; + priv->debug_dir = debugfs_create_dir(devname, gpio_la_poll_debug_dir); + debugfs_create_blob("meta_data", 0400, priv->debug_dir, &priv->meta); + debugfs_create_ulong("delay_ns", 0600, priv->debug_dir, &priv->delay_ns); + debugfs_create_ulong("delay_ns_acquisition", 0400, priv->debug_dir, &priv->acq_delay); + debugfs_create_file_unsafe("buf_size", 0600, priv->debug_dir, priv, &fops_buf_size); + debugfs_create_file_unsafe("capture", 0200, priv->debug_dir, priv, &fops_capture); + debugfs_create_file_unsafe("trigger", 0200, priv->debug_dir, priv, &fops_trigger); + + dev_info(dev, "initialized"); + return 0; +} + +static int gpio_la_poll_remove(struct platform_device *pdev) +{ + struct gpio_la_poll_priv *priv = platform_get_drvdata(pdev); + + mutex_lock(&priv->blob_lock); + debugfs_remove_recursive(priv->debug_dir); + mutex_unlock(&priv->blob_lock); + mutex_destroy(&priv->blob_lock); + + return 0; +} + +static const struct of_device_id gpio_la_poll_of_match[] = { + { .compatible = GPIO_LA_NAME, }, + { } +}; +MODULE_DEVICE_TABLE(of, gpio_la_poll_of_match); + +static struct platform_driver gpio_la_poll_device_driver = { + .probe = gpio_la_poll_probe, + .remove = gpio_la_poll_remove, + .driver = { + .name = GPIO_LA_NAME, + .of_match_table = gpio_la_poll_of_match, + } +}; + +static int __init gpio_la_poll_init(void) +{ + gpio_la_poll_debug_dir = debugfs_create_dir(GPIO_LA_NAME, NULL); + + return platform_driver_register(&gpio_la_poll_device_driver); +} +late_initcall(gpio_la_poll_init); + +static void __exit gpio_la_poll_exit(void) +{ + platform_driver_unregister(&gpio_la_poll_device_driver); + debugfs_remove_recursive(gpio_la_poll_debug_dir); +} +module_exit(gpio_la_poll_exit); + +MODULE_AUTHOR("Wolfram Sang "); +MODULE_DESCRIPTION("Sloppy logic analyzer using GPIOs"); +MODULE_LICENSE("GPL"); diff --git a/tools/gpio/gpio-sloppy-logic-analyzer.sh b/tools/gpio/gpio-sloppy-logic-analyzer.sh new file mode 100755 index 000000000000..ed21a110df5e --- /dev/null +++ b/tools/gpio/gpio-sloppy-logic-analyzer.sh @@ -0,0 +1,246 @@ +#!/bin/sh -eu +# SPDX-License-Identifier: GPL-2.0 +# +# Helper script for the Linux Kernel GPIO sloppy logic analyzer +# +# Copyright (C) Wolfram Sang +# Copyright (C) Renesas Electronics Corporation + +samplefreq=1000000 +numsamples=250000 +cpusetdefaultdir='/sys/fs/cgroup' +cpusetprefix='cpuset.' +debugdir='/sys/kernel/debug' +ladirname='gpio-sloppy-logic-analyzer' +outputdir="$PWD" +neededcmds='taskset zip' +max_chans=8 +duration= +initcpu= +listinstances=0 +lainstance= +lasysfsdir= +triggerdat= +trigger_bindat= +progname="${0##*/}" +print_help() +{ + cat << EOF +$progname - helper script for the Linux Kernel Sloppy GPIO Logic Analyzer +Available options: + -c|--cpu : which CPU to isolate for sampling. Only needed once. Default <1>. + Remember that a more powerful CPU gives you higher sampling speeds. + Also CPU0 is not recommended as it usually does extra bookkeeping. + -d|--duration-us : number of microseconds to sample. Overrides -n, no default value. + -h|--help: print this help + -i|--instance : name of the logic analyzer in case you have multiple instances. Default + to first instance found + -k|--kernel-debug-dir : path to the kernel debugfs mountpoint. Default: <$debugdir> + -l|--list-instances: list all available instances + -n|--num_samples : number of samples to acquire. Default <$numsamples> + -o|--output-dir : directory to put the result files. Default: current dir + -s|--sample_freq : desired sampling frequency. Might be capped if too large. + Default: <1000000> + -t|--trigger : pattern to use as trigger. consists of two-char pairs. First + char is channel number starting at "1". Second char is trigger level: + "L" - low; "H" - high; "R" - rising; "F" - falling + These pairs can be combined with "+", so "1H+2F" triggers when probe 1 + is high while probe 2 has a falling edge. You can have multiple triggers + combined with ",". So, "1H+2F,1H+2R" is like the example before but it + waits for a rising edge on probe 2 while probe 1 is still high after the + first trigger has been met. + Trigger data will only be used for the next capture and then be erased. + + is an integer value where SI units "T", "G", "M", "K" are recognized, e.g. '1M500K' is 1500000. + +Examples: +Samples $numsamples values at 1MHz with an already prepared CPU or automatically prepares CPU1 if needed, +use the first logic analyzer instance found: + '$progname' +Samples 50us at 2MHz waiting for a falling edge on channel 2. CPU and instance as above: + '$progname -d 50 -s 2M -t "2F"' + +Note that the process exits after checking all parameters but a sub-process still works in +the background. The result is only available once the sub-process finishes. + +Result is a .sr file to be consumed with PulseView from the free Sigrok project. It is +a zip file which also contains the binary sample data which may be consumed by others. +The filename is the logic analyzer instance name plus a since-epoch timestamp. +EOF +} + +fail() +{ + echo "$1" + exit 1 +} + +parse_si() +{ + conv_si="$(printf $1 | sed 's/[tT]+\?/*1000G+/g; s/[gG]+\?/*1000M+/g; s/[mM]+\?/*1000K+/g; s/[kK]+\?/*1000+/g; s/+$//')" + si_val="$((conv_si))" +} +set_newmask() +{ + for f in $(find "$1" -iname "$2"); do echo "$newmask" > "$f" 2>/dev/null || true; done +} + +init_cpu() +{ + isol_cpu="$1" + + [ -d "$lacpusetdir" ] || mkdir "$lacpusetdir" + + cur_cpu=$(cat "${lacpusetfile}cpus") + [ "$cur_cpu" = "$isol_cpu" ] && return + [ -z "$cur_cpu" ] || fail "CPU$isol_cpu requested but CPU$cur_cpu already isolated" + + echo "$isol_cpu" > "${lacpusetfile}cpus" || fail "Could not isolate CPU$isol_cpu. Does it exist?" + echo 1 > "${lacpusetfile}cpu_exclusive" + echo 0 > "${lacpusetfile}mems" + + oldmask=$(cat /proc/irq/default_smp_affinity) + newmask=$(printf "%x" $((0x$oldmask & ~(1 << isol_cpu)))) + + set_newmask '/proc/irq' '*smp_affinity' + set_newmask '/sys/devices/virtual/workqueue/' 'cpumask' + + # Move tasks away from isolated CPU + for p in $(ps -o pid | tail -n +2); do + mask=$(taskset -p "$p") || continue + # Ignore tasks with a custom mask, i.e. not equal $oldmask + [ "${mask##*: }" = "$oldmask" ] || continue + taskset -p "$newmask" "$p" || continue + done 2>/dev/null >/dev/null + + # Big hammer! Working with 'rcu_momentary_dyntick_idle()' for a more fine-grained solution + # still printed warnings. Same for re-enabling the stall detector after sampling. + echo 1 > /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress + + cpufreqgov="/sys/devices/system/cpu/cpu$isol_cpu/cpufreq/scaling_governor" + [ -w "$cpufreqgov" ] && echo 'performance' > "$cpufreqgov" || true +} + +parse_triggerdat() +{ + oldifs="$IFS" + IFS=','; for trig in $1; do + mask=0; val1=0; val2=0 + IFS='+'; for elem in $trig; do + chan=${elem%[lhfrLHFR]} + mode=${elem#$chan} + # Check if we could parse something and the channel number fits + [ "$chan" != "$elem" ] && [ "$chan" -le $max_chans ] || fail "Trigger syntax error: $elem" + bit=$((1 << (chan - 1))) + mask=$((mask | bit)) + case $mode in + [hH]) val1=$((val1 | bit)); val2=$((val2 | bit));; + [fF]) val1=$((val1 | bit));; + [rR]) val2=$((val2 | bit));; + esac + done + trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val1)" + [ $val1 -ne $val2 ] && trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val2)" + done + IFS="$oldifs" +} + +do_capture() +{ + taskset "$1" echo 1 > "$lasysfsdir"/capture || fail "Capture error! Check kernel log" + + srtmp=$(mktemp -d) + echo 1 > "$srtmp"/version + cp "$lasysfsdir"/sample_data "$srtmp"/logic-1-1 + cat > "$srtmp"/metadata << EOF +[global] +sigrok version=0.2.0 + +[device 1] +capturefile=logic-1 +total probes=$(wc -l < "$lasysfsdir"/meta_data) +samplerate=${samplefreq}Hz +unitsize=1 +EOF + cat "$lasysfsdir"/meta_data >> "$srtmp"/metadata + + zipname="$outputdir/${lasysfsdir##*/}-$(date +%s).sr" + zip -jq "$zipname" "$srtmp"/* + rm -rf "$srtmp" + delay_ack=$(cat "$lasysfsdir"/delay_ns_acquisition) + [ "$delay_ack" -eq 0 ] && delay_ack=1 + echo "Logic analyzer done. Saved '$zipname'" + echo "Max sample frequency this time: $((1000000000 / delay_ack))Hz." +} + +rep=$(getopt -a -l cpu:,duration-us:,help,instance:,list-instances,kernel-debug-dir:,num_samples:,output-dir:,sample_freq:,trigger: -o c:d:hi:k:ln:o:s:t: -- "$@") || exit 1 +eval set -- "$rep" +while true; do + case "$1" in + -c|--cpu) initcpu="$2"; shift;; + -d|--duration-us) parse_si $2; duration=$si_val; shift;; + -h|--help) print_help; exit 0;; + -i|--instance) lainstance="$2"; shift;; + -k|--kernel-debug-dir) debugdir="$2"; shift;; + -l|--list-instances) listinstances=1;; + -n|--num_samples) parse_si $2; numsamples=$si_val; shift;; + -o|--output-dir) outputdir="$2"; shift;; + -s|--sample_freq) parse_si $2; samplefreq=$si_val; shift;; + -t|--trigger) triggerdat="$2"; shift;; + --) break;; + *) fail "error parsing command line: $*";; + esac + shift +done + +for f in $neededcmds; do + command -v "$f" >/dev/null || fail "Command '$f' not found" +done + +# print cpuset mountpoint if any, errorcode > 0 if noprefix option was found +cpusetdir=$(awk '$3 == "cgroup" && $4 ~ /cpuset/ { print $2; exit (match($4, /noprefix/) > 0) }' /proc/self/mounts) || cpusetprefix='' +if [ -z "$cpusetdir" ]; then + cpusetdir="$cpusetdefaultdir" + [ -d $cpusetdir ] || mkdir $cpusetdir + mount -t cgroup -o cpuset none $cpusetdir || fail "Couldn't mount cpusets. Not in kernel or already in use?" +fi + +lacpusetdir="$cpusetdir/$ladirname" +lacpusetfile="$lacpusetdir/$cpusetprefix" +sysfsdir="$debugdir/$ladirname" + +[ "$samplefreq" -ne 0 ] || fail "Invalid sample frequency" + +[ -d "$sysfsdir" ] || fail "Could not find logic analyzer root dir '$sysfsdir'. Module loaded?" +[ -x "$sysfsdir" ] || fail "Could not access logic analyzer root dir '$sysfsdir'. Need root?" + +[ $listinstances -gt 0 ] && find "$sysfsdir" -mindepth 1 -type d | sed 's|.*/||' && exit 0 + +if [ -n "$lainstance" ]; then + lasysfsdir="$sysfsdir/$lainstance" +else + lasysfsdir=$(find "$sysfsdir" -mindepth 1 -type d -print -quit) +fi +[ -d "$lasysfsdir" ] || fail "Logic analyzer directory '$lasysfsdir' not found!" +[ -d "$outputdir" ] || fail "Output directory '$outputdir' not found!" + +[ -n "$initcpu" ] && init_cpu "$initcpu" +[ -d "$lacpusetdir" ] || { echo "Auto-Isolating CPU1"; init_cpu 1; } + +ndelay=$((1000000000 / samplefreq)) +echo "$ndelay" > "$lasysfsdir"/delay_ns + +[ -n "$duration" ] && numsamples=$((samplefreq * duration / 1000000)) +echo $numsamples > "$lasysfsdir"/buf_size + +if [ -n "$triggerdat" ]; then + parse_triggerdat "$triggerdat" + printf "$trigger_bindat" > "$lasysfsdir"/trigger 2>/dev/null || fail "Trigger data '$triggerdat' rejected" +fi + +workcpu=$(cat "${lacpusetfile}effective_cpus") +[ -n "$workcpu" ] || fail "No isolated CPU found" +cpumask=$(printf '%x' $((1 << workcpu))) +instance=${lasysfsdir##*/} +echo "Setting up '$instance': $numsamples samples at ${samplefreq}Hz with ${triggerdat:-no} trigger using CPU$workcpu" +do_capture "$cpumask" &