On 22.05.2023 21:37:49, 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 in > device tree M_CAN node. Please add a sentence why you introduce polling mode, i.e. there are SoCs where the M_CAN interrupt is not available on the CPUs (which are running Linux). > 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 > --- > Changelog: > v7: > - Clean up m_can_platform.c if/else section after removing poll-interval > - Remove poll-interval from patch description > v6: > - Move hrtimer stop/start function calls to m_can_open and m_can_close to > support power suspend/resume > v5: > - Change dev_dbg to dev_info if hardware interrupt exists and polling > is enabled > v4: > - No changes > v3: > - Create a define for 1 ms polling interval > - Change plarform_get_irq to optional to not print error msg > v2: > - Add functionality to check for 'poll-interval' property in MCAN node > - Add 'polling' flag in driver to check if device is using polling method > - Check for timer polling and hardware interrupt cases, default to > hardware interrupt method > - Change ns_to_ktime() to ms_to_ktime() > --- > drivers/net/can/m_can/m_can.c | 33 ++++++++++++++++++++++++-- > drivers/net/can/m_can/m_can.h | 4 ++++ > drivers/net/can/m_can/m_can_platform.c | 25 ++++++++++++++++--- > 3 files changed, 57 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index a5003435802b..f273d989bdff 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -308,6 +309,9 @@ enum m_can_reg { > #define TX_EVENT_MM_MASK GENMASK(31, 24) > #define TX_EVENT_TXTS_MASK GENMASK(15, 0) > > +/* Hrtimer polling interval */ > +#define HRTIMER_POLL_INTERVAL 1 > + > /* The ID and DLC registers are adjacent in M_CAN FIFO memory, > * and we can save a (potentially slow) bus round trip by combining > * reads and writes to them. > @@ -895,7 +899,7 @@ static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus, > netdev_dbg(dev, "Arbitration phase error detected\n"); > work_done += m_can_handle_lec_err(dev, lec); > } > - > + Unrelated change. I've send a separate patch to fix the problem. > if (is_lec_err(dlec)) { > netdev_dbg(dev, "Data phase error detected\n"); > work_done += m_can_handle_lec_err(dev, dlec); > @@ -1414,6 +1418,12 @@ static int m_can_start(struct net_device *dev) > > m_can_enable_all_interrupts(cdev); > > + if (cdev->polling) { > + dev_dbg(cdev->dev, "Start hrtimer\n"); > + hrtimer_start(&cdev->hrtimer, ms_to_ktime(HRTIMER_POLL_INTERVAL), > + HRTIMER_MODE_REL_PINNED); > + } > + > return 0; > } > > @@ -1571,6 +1581,11 @@ static void m_can_stop(struct net_device *dev) > /* disable all interrupts */ > m_can_disable_all_interrupts(cdev); > > + if (cdev->polling) { > + dev_dbg(cdev->dev, "Disabling the hrtimer\n"); > + hrtimer_cancel(&cdev->hrtimer); > + } > + This might be a racy. Please move the disabling of the hrtimer before disabling all interrupts. This makes it also symmetric with respect to m_can_start(). > /* Set init mode to disengage from the network */ > m_can_config_endisable(cdev, true); > > @@ -1793,6 +1808,18 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, > return NETDEV_TX_OK; > } > > +static 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(HRTIMER_POLL_INTERVAL)); > + > + return HRTIMER_RESTART; > +} > + > static int m_can_open(struct net_device *dev) > { > struct m_can_classdev *cdev = netdev_priv(dev); > @@ -1831,9 +1858,11 @@ static int m_can_open(struct net_device *dev) > err = request_threaded_irq(dev->irq, NULL, m_can_isr, > IRQF_ONESHOT, > dev->name, dev); > - } else { > + } else if (!cdev->polling) { > err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name, > dev); > + } else { > + cdev->hrtimer.function = &hrtimer_callback; I think you can move this assignment to m_can_class_register(). We only need to set the function once. > } > > 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..e9db5cce4e68 100644 > --- a/drivers/net/can/m_can/m_can.h > +++ b/drivers/net/can/m_can/m_can.h > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -93,6 +94,9 @@ struct m_can_classdev { > int is_peripheral; > > struct mram_cfg mcfg[MRAM_CFG_NUM]; > + > + struct hrtimer hrtimer; > + bool polling; > }; > > 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 94dc82644113..b639c9e645d3 100644 > --- a/drivers/net/can/m_can/m_can_platform.c > +++ b/drivers/net/can/m_can/m_can_platform.c > @@ -5,6 +5,7 @@ > // > // Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/ > > +#include > #include > #include > > @@ -96,12 +97,30 @@ static int m_can_plat_probe(struct platform_device *pdev) > goto probe_fail; > > addr = devm_platform_ioremap_resource_byname(pdev, "m_can"); > - irq = platform_get_irq_byname(pdev, "int0"); I think irq will be uninitialized after this change. Although the compiler doesn't complain :( BTW: I think we don't need the "polling" variable in the priv. We can make use of "irq". "irq" being 0 means use polling. > - if (IS_ERR(addr) || irq < 0) { > - ret = -EINVAL; > + if (IS_ERR(addr)) { > + ret = PTR_ERR(addr); > goto probe_fail; > } > > + if (device_property_present(mcan_class->dev, "interrupts") || > + device_property_present(mcan_class->dev, "interrupt-names")) { > + irq = platform_get_irq_byname(pdev, "int0"); > + mcan_class->polling = false; > + if (irq == -EPROBE_DEFER) { > + ret = -EPROBE_DEFER; > + goto probe_fail; > + } > + if (irq < 0) { > + ret = -ENXIO; Please return the original error code. > + goto probe_fail; > + } > + } else { > + mcan_class->polling = true; > + dev_dbg(mcan_class->dev, "Polling enabled, initialize hrtimer"); > + hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, > + HRTIMER_MODE_REL_PINNED); > + } > + > /* message ram could be shared */ > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram"); > if (!res) { regards, 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 |