Hello Marc,
On 4/14/2023 1:20 PM, Marc Kleine-Budde wrote:
On 13.04.2023 17:30:51, Judith Mendez wrote:
Add a hrtimer to MCAN struct. Each MCAN will have its own
hrtimer instantiated if there is no hardware interrupt found.
The hrtimer will generate a software interrupt every 1 ms. In
Are you sure about the 1ms?
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@xxxxxx>
---
drivers/net/can/m_can/m_can.c | 24 ++++++++++++++++++++++--
drivers/net/can/m_can/m_can.h | 3 +++
drivers/net/can/m_can/m_can_platform.c | 9 +++++++--
3 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 8e83d6963d85..bb9d53f4d3cc 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>
#include "m_can.h"
@@ -1584,6 +1585,11 @@ static int m_can_close(struct net_device *dev)
if (!cdev->is_peripheral)
napi_disable(&cdev->napi);
+ if (dev->irq < 0) {
+ dev_info(cdev->dev, "Disabling the hrtimer\n");
Make it a dev_dbg() or remove completely.
Will do, thanks.
+ hrtimer_cancel(&cdev->hrtimer);
+ }
+
m_can_stop(dev);
m_can_clk_stop(cdev);
free_irq(dev->irq, dev);
@@ -1792,6 +1798,19 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
return NETDEV_TX_OK;
}
+enum hrtimer_restart hrtimer_callback(struct hrtimer *timer)
+{
+ irqreturn_t ret;
never read value?
I have removed ret completely now.
+ struct m_can_classdev *cdev =
+ container_of(timer, struct m_can_classdev, hrtimer);
+
+ ret = m_can_isr(0, cdev->net);
+
+ hrtimer_forward_now(timer, ns_to_ktime(5 * NSEC_PER_MSEC));
There's ms_to_ktime()....and the "5" doesn't match your patch
description.
+
+ return HRTIMER_RESTART;
+}
+
static int m_can_open(struct net_device *dev)
{
struct m_can_classdev *cdev = netdev_priv(dev);
@@ -1836,8 +1855,9 @@ static int m_can_open(struct net_device *dev)
}
if (err < 0) {
- netdev_err(dev, "failed to request interrupt\n");
- goto exit_irq_fail;
+ dev_info(cdev->dev, "Enabling the hrtimer\n");
+ cdev->hrtimer.function = &hrtimer_callback;
+ hrtimer_start(&cdev->hrtimer, ns_to_ktime(0), HRTIMER_MODE_REL_PINNED);
IMHO it makes no sense to request an IRQ if the device doesn't have one,
and then try to fix up things in the error path. What about this?
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1831,9 +1831,11 @@ 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 (dev->irq) {
err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
dev);
+ } else {
+ // polling
}
if (err < 0) {
}
Thanks for the recommendation, I will include in v2.
/* start the m_can controller */
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index a839dc71dc9b..ed046d77fdb9 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>
/* m_can lec values */
enum m_can_lec_type {
@@ -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 9c1dcf838006..53e1648e9dab 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"
@@ -98,8 +99,12 @@ 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");
if (IS_ERR(addr) || irq < 0) {
What about the IS_ERR(addr) case?
Added, thanks.
- ret = -EINVAL;
- goto probe_fail;
+ if (irq == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ goto probe_fail;
+ }
+ dev_info(mcan_class->dev, "Failed to get irq, initialize hrtimer\n");
+ hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
I don't like it when polling is unconditionally set up in case of an irq
error. I'm not sure if we need an explicit device tree property....
This is an interesting thought, I would definitely like to look more
into this. Though I am thinking it would be part of future optimization
patch. Thanks so much for your recommendation.
regards,
Judith
