From: Oleksij Rempel <o.rempel@pengutronix.de>
To: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: jic23@kernel.org, kamel.bouhara@bootlin.com,
gwendal@chromium.org, a.fatoum@pengutronix.de,
david@lechnology.com, linux-iio@vger.kernel.org,
patrick.havelange@essensium.com, alexandre.belloni@bootlin.com,
mcoquelin.stm32@gmail.com, linux-kernel@vger.kernel.org,
Dan Carpenter <dan.carpenter@oracle.com>,
kernel@pengutronix.de, fabrice.gasnier@st.com,
syednwaris@gmail.com, linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org, alexandre.torgue@st.com
Subject: Re: [PATCH v8 17/22] counter: Add character device interface
Date: Mon, 15 Feb 2021 10:24:12 +0100 [thread overview]
Message-ID: <20210215092412.ptbngqge7m7nyivp@pengutronix.de> (raw)
In-Reply-To: <720278e3aaf3f249657ec18d158eca3f962baf8e.1613131238.git.vilhelm.gray@gmail.com>
Hi William,
On Fri, Feb 12, 2021 at 09:13:41PM +0900, William Breathitt Gray wrote:
> This patch introduces a character device interface for the Counter
> subsystem. Device data is exposed through standard character device read
> operations. Device data is gathered when a Counter event is pushed by
> the respective Counter device driver. Configuration is handled via ioctl
> operations on the respective Counter character device node.
.....
> +/**
> + * counter_push_event - queue event for userspace reading
> + * @counter: pointer to Counter structure
> + * @event: triggered event
> + * @channel: event channel
> + *
> + * Note: If no one is watching for the respective event, it is silently
> + * discarded.
> + */
> +void counter_push_event(struct counter_device *const counter, const u8 event,
> + const u8 channel)
> +{
> + struct counter_event ev = {0};
> + unsigned int copied = 0;
> + unsigned long flags;
> + struct counter_event_node *event_node;
> + struct counter_comp_node *comp_node;
> +
> + ev.timestamp = ktime_get_ns();
> + ev.watch.event = event;
> + ev.watch.channel = channel;
> +
> + /* Could be in an interrupt context, so use a raw spin lock */
> + raw_spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> + /* Search for event in the list */
> + list_for_each_entry(event_node, &counter->events_list, l)
> + if (event_node->event == event &&
> + event_node->channel == channel)
> + break;
> +
> + /* If event is not in the list */
> + if (&event_node->l == &counter->events_list)
> + goto exit_early;
To cover my "interrupt-counter" use case, I added following line here to
convert the tail drop fifo to the head drop fifo:
+ list_for_each_entry(comp_node, &event_node->comp_list, l)
+ to_copy += sizeof(ev);
+
+ while (kfifo_avail(&counter->events) < to_copy)
+ kfifo_skip(&counter->events);
May be it make sense to make it optional and integrate in to you patches
before it goes mainline?
Regards,
Oleksij
--
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next prev parent reply other threads:[~2021-02-15 9:25 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-12 12:13 [PATCH v8 00/22] Introduce the Counter character device interface William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 01/22] docs: counter: Consolidate Counter sysfs attributes documentation William Breathitt Gray
2021-02-14 16:57 ` Jonathan Cameron
2021-02-15 11:05 ` William Breathitt Gray
2021-02-20 16:25 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 02/22] docs: counter: Fix spelling William Breathitt Gray
2021-02-20 16:26 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write William Breathitt Gray
2021-02-20 16:30 ` David Lechner
2021-02-22 2:06 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 04/22] counter: 104-quad-8: Annotate hardware config module parameter William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 05/22] counter: 104-quad-8: Add const qualifiers for quad8_preset_register_set William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 06/22] counter: 104-quad-8: Add const qualifier for functions_list array William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 07/22] counter: 104-quad-8: Add const qualifier for actions_list array William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 08/22] counter: ftm-quaddec: " William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 09/22] counter: Return error code on invalid modes William Breathitt Gray
2021-02-14 17:07 ` Jonathan Cameron
2021-02-20 16:43 ` David Lechner
2021-02-22 4:42 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 10/22] counter: Standardize to ERANGE for limit exceeded errors William Breathitt Gray
2021-02-14 17:10 ` Jonathan Cameron
2021-02-16 1:26 ` William Breathitt Gray
2021-02-21 14:03 ` Jonathan Cameron
2021-02-20 16:48 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 11/22] counter: Rename counter_signal_value to counter_signal_level William Breathitt Gray
2021-02-20 16:52 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 12/22] counter: Rename counter_count_function to counter_function William Breathitt Gray
2021-02-14 17:13 ` Jonathan Cameron
2021-02-20 16:56 ` David Lechner
2021-02-23 5:14 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 13/22] counter: Internalize sysfs interface code William Breathitt Gray
2021-02-14 17:32 ` Jonathan Cameron
2021-02-20 17:50 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 14/22] counter: Update counter.h comments to reflect sysfs internalization William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 15/22] docs: counter: Update " William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 16/22] counter: Move counter enums to uapi header William Breathitt Gray
2021-02-20 23:55 ` David Lechner
2021-02-12 12:13 ` [PATCH v8 17/22] counter: Add character device interface William Breathitt Gray
2021-02-14 18:06 ` Jonathan Cameron
2021-02-24 5:34 ` William Breathitt Gray
2021-02-15 9:24 ` Oleksij Rempel [this message]
2021-02-16 1:53 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 18/22] docs: counter: Document " William Breathitt Gray
2021-02-14 17:48 ` Jonathan Cameron
2021-02-22 10:11 ` Pavel Machek
2021-02-26 0:27 ` William Breathitt Gray
2021-02-26 0:22 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 19/22] counter: Implement extension*_name sysfs attributes William Breathitt Gray
2021-02-14 18:09 ` Jonathan Cameron
2021-02-19 8:51 ` William Breathitt Gray
2021-02-21 14:05 ` Jonathan Cameron
2021-02-25 23:32 ` William Breathitt Gray
2021-02-27 15:14 ` Jonathan Cameron
2021-02-12 12:13 ` [PATCH v8 20/22] counter: Implement events_queue_size sysfs attribute William Breathitt Gray
2021-02-14 18:11 ` Jonathan Cameron
2021-02-18 10:32 ` William Breathitt Gray
2021-02-21 15:51 ` Jonathan Cameron
2021-02-26 0:03 ` William Breathitt Gray
2021-02-27 0:14 ` David Lechner
2021-02-27 0:20 ` William Breathitt Gray
2021-02-27 15:18 ` Jonathan Cameron
2021-02-28 2:46 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 21/22] counter: 104-quad-8: Replace mutex with spinlock William Breathitt Gray
2021-02-14 18:19 ` Jonathan Cameron
2021-02-16 2:16 ` William Breathitt Gray
2021-02-16 19:27 ` Jonathan Cameron
2021-02-18 10:16 ` William Breathitt Gray
2021-02-12 12:13 ` [PATCH v8 22/22] counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8 William Breathitt Gray
2021-02-14 18:24 ` Jonathan Cameron
2021-02-19 9:21 ` William Breathitt Gray
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