[PATCH 06/15] can: m_can: Avoid reading irqstatus twice

From: Markus Schneider-Pargmann
Date: Wed Nov 16 2022 - 15:54:37 EST


For peripheral devices the m_can_rx_handler is called directly after
setting cdev->irqstatus. This means we don't have to read the irqstatus
again in m_can_rx_handler. Avoid this by adding a parameter that is
false for direct calls.

Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
---
drivers/net/can/m_can/m_can.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 5c00c6162058..0efa6dee0617 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -896,14 +896,13 @@ static int m_can_handle_bus_errors(struct net_device *dev, u32 irqstatus,
return work_done;
}

-static int m_can_rx_handler(struct net_device *dev, int quota)
+static int m_can_rx_handler(struct net_device *dev, int quota, u32 irqstatus)
{
struct m_can_classdev *cdev = netdev_priv(dev);
int rx_work_or_err;
int work_done = 0;
- u32 irqstatus, psr;
+ u32 psr;

- irqstatus = cdev->irqstatus | m_can_read(cdev, M_CAN_IR);
if (!irqstatus)
goto end;

@@ -947,12 +946,12 @@ static int m_can_rx_handler(struct net_device *dev, int quota)
return work_done;
}

-static int m_can_rx_peripheral(struct net_device *dev)
+static int m_can_rx_peripheral(struct net_device *dev, u32 irqstatus)
{
struct m_can_classdev *cdev = netdev_priv(dev);
int work_done;

- work_done = m_can_rx_handler(dev, NAPI_POLL_WEIGHT);
+ work_done = m_can_rx_handler(dev, NAPI_POLL_WEIGHT, irqstatus);

/* Don't re-enable interrupts if the driver had a fatal error
* (e.g., FIFO read failure).
@@ -968,8 +967,11 @@ static int m_can_poll(struct napi_struct *napi, int quota)
struct net_device *dev = napi->dev;
struct m_can_classdev *cdev = netdev_priv(dev);
int work_done;
+ u32 irqstatus;
+
+ irqstatus = cdev->irqstatus | m_can_read(cdev, M_CAN_IR);

- work_done = m_can_rx_handler(dev, quota);
+ work_done = m_can_rx_handler(dev, quota, irqstatus);

/* Don't re-enable interrupts if the driver had a fatal error
* (e.g., FIFO read failure).
@@ -1080,7 +1082,7 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
m_can_disable_all_interrupts(cdev);
if (!cdev->is_peripheral)
napi_schedule(&cdev->napi);
- else if (m_can_rx_peripheral(dev) < 0)
+ else if (m_can_rx_peripheral(dev, ir) < 0)
goto out_fail;
}

--
2.38.1