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Message-ID: <20230424-canon-primal-ece722b184d4-mkl@pengutronix.de>
Date: Mon, 24 Apr 2023 22:14:53 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Judith Mendez <jm@...com>
Cc: Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
Wolfgang Grandegger <wg@...ndegger.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
"David S . Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, linux-can@...r.kernel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
Schuyler Patton <spatton@...com>, Nishanth Menon <nm@...com>,
Vignesh Raghavendra <vigneshr@...com>,
Tero Kristo <kristo@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
Oliver Hartkopp <socketcan@...tkopp.net>
Subject: Re: [PATCH v2 1/4] can: m_can: Add hrtimer to generate software
interrupt
On 24.04.2023 14:53:59, Judith Mendez wrote:
> Add an hrtimer to MCAN class device. Each MCAN will have its own
> hrtimer instantiated if there is no hardware interrupt found and
> poll-interval property is defined in device tree M_CAN node.
>
> The hrtimer will generate a software interrupt every 1 ms. In
> hrtimer callback, we check if there is a transaction pending by
> reading a register, then process by calling the isr if there is.
>
> Signed-off-by: Judith Mendez <jm@...com>
> ---
> Changelog:
> v2:
> 1. Add poll-interval to MCAN class device to check if poll-interval propery is
> present in MCAN node, this enables timer polling method.
> 2. Add 'polling' flag to MCAN class device to check if a device is using timer
> polling method
> 3. Check if both timer polling and hardware interrupt are enabled for a MCAN
> device, default to hardware interrupt mode if both are enabled.
> 4. Changed ms_to_ktime() to ns_to_ktime()
> 5. Removed newlines, tabs, and restructure if/else section.
>
> drivers/net/can/m_can/m_can.c | 30 ++++++++++++++++++++-----
> drivers/net/can/m_can/m_can.h | 5 +++++
> drivers/net/can/m_can/m_can_platform.c | 31 ++++++++++++++++++++++++--
> 3 files changed, 59 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index a5003435802b..33e094f88da1 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -23,6 +23,7 @@
> #include <linux/pinctrl/consumer.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/hrtimer.h>
keep the list of includes sorted
>
> #include "m_can.h"
>
> @@ -1587,6 +1588,11 @@ static int m_can_close(struct net_device *dev)
> if (!cdev->is_peripheral)
> napi_disable(&cdev->napi);
>
> + if (cdev->polling) {
> + dev_dbg(cdev->dev, "Disabling the hrtimer\n");
> + hrtimer_cancel(&cdev->hrtimer);
> + }
> +
> m_can_stop(dev);
> m_can_clk_stop(cdev);
> free_irq(dev->irq, dev);
> @@ -1793,6 +1799,18 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
> return NETDEV_TX_OK;
> }
>
> +enum hrtimer_restart hrtimer_callback(struct hrtimer *timer)
> +{
> + struct m_can_classdev *cdev =
> + container_of(timer, struct m_can_classdev, hrtimer);
> +
> + m_can_isr(0, cdev->net);
> +
> + hrtimer_forward_now(timer, ms_to_ktime(1));
Please create a define for this
> +
> + return HRTIMER_RESTART;
> +}
> +
> static int m_can_open(struct net_device *dev)
> {
> struct m_can_classdev *cdev = netdev_priv(dev);
> @@ -1827,13 +1845,15 @@ static int m_can_open(struct net_device *dev)
> }
>
> INIT_WORK(&cdev->tx_work, m_can_tx_work_queue);
> -
> err = request_threaded_irq(dev->irq, NULL, m_can_isr,
> - IRQF_ONESHOT,
> - dev->name, dev);
> - } else {
> - err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
> + IRQF_ONESHOT, dev->name, dev);
> + } else if (!cdev->polling) {
> + err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
> dev);
No need to change the indention
> + } else {
> + dev_dbg(cdev->dev, "Start hrtimer\n");
> + cdev->hrtimer.function = &hrtimer_callback;
> + hrtimer_start(&cdev->hrtimer, ms_to_ktime(cdev->poll_interval), HRTIMER_MODE_REL_PINNED);
> }
>
> if (err < 0) {
> diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
> index a839dc71dc9b..1ba87eb23f8e 100644
> --- a/drivers/net/can/m_can/m_can.h
> +++ b/drivers/net/can/m_can/m_can.h
> @@ -28,6 +28,7 @@
> #include <linux/pm_runtime.h>
> #include <linux/slab.h>
> #include <linux/uaccess.h>
> +#include <linux/hrtimer.h>
keep the list of includes sorted
>
> /* m_can lec values */
> enum m_can_lec_type {
> @@ -93,6 +94,10 @@ struct m_can_classdev {
> int is_peripheral;
>
> struct mram_cfg mcfg[MRAM_CFG_NUM];
> +
> + struct hrtimer hrtimer;
> + u32 poll_interval;
> + u8 polling;
bool
> };
>
> struct m_can_classdev *m_can_class_allocate_dev(struct device *dev, int sizeof_priv);
> diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c
> index 9c1dcf838006..e899c04edc01 100644
> --- a/drivers/net/can/m_can/m_can_platform.c
> +++ b/drivers/net/can/m_can/m_can_platform.c
> @@ -7,6 +7,7 @@
>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/hrtimer.h>
>
> #include "m_can.h"
>
> @@ -97,11 +98,37 @@ static int m_can_plat_probe(struct platform_device *pdev)
>
> addr = devm_platform_ioremap_resource_byname(pdev, "m_can");
> irq = platform_get_irq_byname(pdev, "int0");
use platform_get_irq_byname_optional(), it doesn't print an error
message.
> - if (IS_ERR(addr) || irq < 0) {
> - ret = -EINVAL;
> + if (irq == -EPROBE_DEFER) {
> + ret = -EPROBE_DEFER;
> goto probe_fail;
> }
>
> + if (IS_ERR(addr)) {
> + ret = PTR_ERR(addr);
> + goto probe_fail;
> + }
please move the error check for "addr" directly after the "addr = "
assignment.
> +
> + mcan_class->polling = 0;
No need to init as "0"
> + if (device_property_present(mcan_class->dev, "poll-interval")) {
> + mcan_class->polling = 1;
> + }
No need for the { } here.
> +
> + if (!mcan_class->polling && irq < 0) {
> + ret = -ENODATA;
-ENXIO
> + dev_dbg(mcan_class->dev, "Polling not enabled\n");
print a proper error message using dev_err_probe("IRQ %s not found and
polling not activated\n")
> + goto probe_fail;
> + }
> +
> + if (mcan_class->polling && irq > 0) {
> + mcan_class->polling = 0;
> + dev_dbg(mcan_class->dev, "Polling not enabled, hardware interrupt exists\n");
> + }
> +
> + if (mcan_class->polling && irq < 0) {
> + dev_dbg(mcan_class->dev, "Polling enabled, initialize hrtimer");
> + hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
> + }
combine both if (mcan_class->polling) into one.
> +
> /* message ram could be shared */
> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram");
> if (!res) {
> --
> 2.17.1
>
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung Nürnberg | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
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