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Message-ID: <0ba17779-9cd9-6cb2-a79c-6b14b73a42db@ti.com>
Date: Thu, 6 Jul 2023 10:20:59 -0500
From: Judith Mendez <jm@...com>
To: Marc Kleine-Budde <mkl@...gutronix.de>
CC: Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
Wolfgang Grandegger <wg@...ndegger.com>,
"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>,
Tero Kristo <kristo@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
<devicetree@...r.kernel.org>,
Oliver Hartkopp <socketcan@...tkopp.net>,
Simon Horman <simon.horman@...igine.com>
Subject: Re: [PATCH 2/2] can: m_can: Add hrtimer to generate software
interrupt
Hi Marc
On 7/6/23 2:25 AM, Marc Kleine-Budde wrote:
> On 05.07.2023 14:53:56, Judith Mendez wrote:
>> Introduce timer polling method to MCAN since some SoCs may not
>> have M_CAN interrupt routed to A53 Linux and do not have
>> interrupt property in device tree M_CAN node.
>>
>> On AM62x SoC, MCANs on MCU domain do not have hardware interrupt
>> routed to A53 Linux, instead they will use timer polling method.
>>
>> 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. The timer 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.
>>
>> Tested-by: Hiago De Franco <hiago.franco@...adex.com> # Toradex Verdin AM62
>> Reviewed-by: Tony Lindgren <tony@...mide.com>
>> Signed-off-by: Judith Mendez <jm@...com>
>> ---
>> Changelog:
>> v9:
>> - Change add MS to HRTIMER_POLL_INTERVAL
>> - Change syntax from "= 0" to "!"
>> v8:
>> - Cancel hrtimer after interrupts in m_can_stop
>> - Move assignment of hrtimer_callback to m_can_class_register()
>> - Initialize irq = 0 if polling mode is used
>
> This change has been lost :(
True
>
>> - Add reson for polling mode in commit msg
>> - Remove unrelated change
>> - Remove polling flag
>> 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 | 32 +++++++++++++++++++++++++-
>> drivers/net/can/m_can/m_can.h | 3 +++
>> drivers/net/can/m_can/m_can_platform.c | 23 +++++++++++++++---
>> 3 files changed, 54 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
>> index c5af92bcc9c9..13fd84b2e2dd 100644
>> --- a/drivers/net/can/m_can/m_can.c
>> +++ b/drivers/net/can/m_can/m_can.c
>> @@ -11,6 +11,7 @@
>> #include <linux/bitfield.h>
>> #include <linux/can/dev.h>
>> #include <linux/ethtool.h>
>> +#include <linux/hrtimer.h>
>> #include <linux/interrupt.h>
>> #include <linux/io.h>
>> #include <linux/iopoll.h>
>> @@ -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_MS 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.
>> @@ -1414,6 +1418,12 @@ static int m_can_start(struct net_device *dev)
>>
>> m_can_enable_all_interrupts(cdev);
>>
>> + if (!dev->irq) {
>> + dev_dbg(cdev->dev, "Start hrtimer\n");
>> + hrtimer_start(&cdev->hrtimer, ms_to_ktime(HRTIMER_POLL_INTERVAL_MS),
>> + HRTIMER_MODE_REL_PINNED);
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -1568,6 +1578,11 @@ static void m_can_stop(struct net_device *dev)
>> {
>> struct m_can_classdev *cdev = netdev_priv(dev);
>>
>> + if (!dev->irq) {
>> + dev_dbg(cdev->dev, "Stop hrtimer\n");
>> + hrtimer_cancel(&cdev->hrtimer);
>> + }
>> +
>> /* disable all interrupts */
>> m_can_disable_all_interrupts(cdev);
>>
>> @@ -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_MS));
>> +
>> + return HRTIMER_RESTART;
>> +}
>> +
>> static int m_can_open(struct net_device *dev)
>> {
>> struct m_can_classdev *cdev = netdev_priv(dev);
>> @@ -1831,7 +1858,7 @@ 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 (dev->irq) {
>> err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
>> dev);
>> }
>> @@ -2027,6 +2054,9 @@ int m_can_class_register(struct m_can_classdev *cdev)
>> goto clk_disable;
>> }
>>
>> + if (!cdev->net->irq)
>> + cdev->hrtimer.function = &hrtimer_callback;
>> +
>> ret = m_can_dev_setup(cdev);
>> if (ret)
>> goto rx_offload_del;
>> diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
>> index a839dc71dc9b..2ac18ac867a4 100644
>> --- a/drivers/net/can/m_can/m_can.h
>> +++ b/drivers/net/can/m_can/m_can.h
>> @@ -15,6 +15,7 @@
>> #include <linux/device.h>
>> #include <linux/dma-mapping.h>
>> #include <linux/freezer.h>
>> +#include <linux/hrtimer.h>
>> #include <linux/interrupt.h>
>> #include <linux/io.h>
>> #include <linux/iopoll.h>
>> @@ -93,6 +94,8 @@ struct m_can_classdev {
>> int is_peripheral;
>>
>> struct mram_cfg mcfg[MRAM_CFG_NUM];
>> +
>> + struct hrtimer hrtimer;
>> };
>>
>> 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..76d11ce38220 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 <linux/hrtimer.h>
>> #include <linux/phy/phy.h>
>> #include <linux/platform_device.h>
>>
>> @@ -96,12 +97,28 @@ static int m_can_plat_probe(struct platform_device *pdev)
>> goto probe_fail;
>
> Please set "irq" to 0 during declaration.
During declaration of irq, it is already set to 0:
int irq, ret = 0;
>
>>
>> addr = devm_platform_ioremap_resource_byname(pdev, "m_can");
>> - irq = platform_get_irq_byname(pdev, "int0");
>> - 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");
>> + if (irq == -EPROBE_DEFER) {
>> + ret = -EPROBE_DEFER;
>> + goto probe_fail;
>> + }
>> + if (irq < 0) {
>> + ret = -EINVAL;
>
> Please return the original error value.
The original value returned is -EINVAL:
- if (IS_ERR(addr) || irq < 0) {
- ret = -EINVAL;
Perhaps I am missing something here?
>
>> + goto probe_fail;
>> + }
>> + } else {
>> + 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) {
>> --
>> 2.34.1
Judith
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