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Message-ID: <20230518193613.15185-3-jm@ti.com>
Date: Thu, 18 May 2023 14:36:13 -0500
From: Judith Mendez <jm@...com>
To: Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
<linux-can@...r.kernel.org>
CC: Wolfgang Grandegger <wg@...ndegger.com>,
Marc Kleine-Budde
<mkl@...gutronix.de>,
"David S . Miller" <davem@...emloft.net>,
Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni
<pabeni@...hat.com>, <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>,
<linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
Oliver Hartkopp <socketcan@...tkopp.net>,
Conor
Dooley <conor+dt@...nel.org>
Subject: [PATCH v6 2/2] can: m_can: Add hrtimer to generate software interrupt
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:
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 | 31 ++++++++++++++++++++++-
drivers/net/can/m_can/m_can.h | 4 +++
drivers/net/can/m_can/m_can_platform.c | 35 +++++++++++++++++++++++---
3 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index a5003435802b..cfb3e433c0dd 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 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 (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);
+ }
+
/* 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;
}
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 <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 +94,9 @@ 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..3e60cebd9d12 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 +97,40 @@ 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");
- if (IS_ERR(addr) || irq < 0) {
- ret = -EINVAL;
+ if (IS_ERR(addr)) {
+ ret = PTR_ERR(addr);
goto probe_fail;
}
+ irq = platform_get_irq_byname_optional(pdev, "int0");
+ if (irq == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ goto probe_fail;
+ }
+
+ if (device_property_present(mcan_class->dev, "interrupts") ||
+ device_property_present(mcan_class->dev, "interrupt-names"))
+ mcan_class->polling = false;
+ else
+ mcan_class->polling = true;
+
+ if (!mcan_class->polling && irq < 0) {
+ ret = -ENXIO;
+ dev_err_probe(mcan_class->dev, ret, "IRQ int0 not found, polling not activated\n");
+ goto probe_fail;
+ }
+
+ if (mcan_class->polling) {
+ if (irq > 0) {
+ mcan_class->polling = false;
+ dev_info(mcan_class->dev, "Polling enabled, using hardware IRQ\n");
+ } 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) {
--
2.17.1
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