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can: m_can: Add hrtimer to generate software interrupt

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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@toradex.com> # Toradex Verdin AM62
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Judith Mendez <jm@ti.com>
Link: https://lore.kernel.org/all/20230707204714.62964-3-jm@ti.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Judith Mendez 2023-07-07 15:47:14 -05:00 committed by Marc Kleine-Budde
parent bb410c03b9
commit b382380c0d
3 changed files with 51 additions and 5 deletions
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32
drivers/net/can/m_can/m_can.c
View file

@ -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;

3
drivers/net/can/m_can/m_can.h
View file

@ -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);

21
drivers/net/can/m_can/m_can_platform.c
View file

@ -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>
@ -82,7 +83,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
void __iomem *addr;
void __iomem *mram_addr;
struct phy *transceiver;
int irq, ret = 0;
int irq = 0, ret = 0;
mcan_class = m_can_class_allocate_dev(&pdev->dev,
sizeof(struct m_can_plat_priv));
@ -96,12 +97,24 @@ 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;
}
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 < 0) {
ret = irq;
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) {