[PATCH v7] flexcan: add err_irq handler for flexcan

[Zhao Qiang]

when flexcan is not physically linked, command 'cantest' will
trigger an err_irq, add err_irq handler for it.

Signed-off-by: Zhao Qiang <b45...@freescale.com>
---
Changes for v2:
        - use a space instead of tab
        - use flexcan_poll_state instead of print
Changes for v3:
        - return IRQ_HANDLED if err is triggered
        - stop transmitted packets when there is an err_interrupt 
Changes for v4:
        - call flexcan_irq 
Changes for v5:
        - move err_int_handling code from flexcan_irq to flexcan_err_irq
        - call flexcan_err_irq from flexcan_irq
Changes for v6:
        - move RX_IRQ handling back to flexcan_irq
Changes for v7:
        - seperate err_irq_handling code from rx_irq_handling code and move it 
to err_irq_handler.

 drivers/net/can/flexcan.c | 73 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 16 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index f425ec2..12385f8 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -208,6 +208,7 @@ struct flexcan_priv {
        void __iomem *base;
        u32 reg_esr;
        u32 reg_ctrl_default;
+       int err_irq;
 
        struct clk *clk_ipg;
        struct clk *clk_per;
@@ -690,6 +691,38 @@ static int flexcan_poll(struct napi_struct *napi, int 
quota)
        return work_done;
 }
 
+static irqreturn_t flexcan_err_irq(int irq, void *dev_id)
+{
+       struct net_device *dev = dev_id;
+       struct flexcan_priv *priv = netdev_priv(dev);
+       struct flexcan_regs __iomem *regs = priv->base;
+       u32 reg_ctrl, reg_esr;
+       irqreturn_t ret = IRQ_NONE;
+
+       reg_esr = flexcan_read(&regs->esr);
+       reg_ctrl = flexcan_read(&regs->ctrl);
+
+       if (reg_esr & FLEXCAN_ESR_ALL_INT) {
+               flexcan_write(reg_esr & FLEXCAN_ESR_ALL_INT, &regs->esr);
+               ret = IRQ_HANDLED;
+       }
+
+       if (reg_esr & FLEXCAN_ESR_ERR_INT)
+               flexcan_write(reg_ctrl & ~FLEXCAN_CTRL_ERR_MSK, &regs->ctrl);
+
+       if ((reg_esr & FLEXCAN_ESR_ERR_STATE) ||
+           flexcan_has_and_handle_berr(priv, reg_esr)) {
+               /* The error bits are cleared on read,
+                * save them for later use.
+                */
+               priv->reg_esr = reg_esr & FLEXCAN_ESR_ERR_BUS;
+               flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
+                             &regs->ctrl);
+               napi_schedule(&priv->napi);
+       }
+       return ret;
+}
+
 static irqreturn_t flexcan_irq(int irq, void *dev_id)
 {
        struct net_device *dev = dev_id;
@@ -698,11 +731,10 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
        struct flexcan_regs __iomem *regs = priv->base;
        u32 reg_iflag1, reg_esr;
 
-       reg_iflag1 = flexcan_read(&regs->iflag1);
        reg_esr = flexcan_read(&regs->esr);
-       /* ACK all bus error and state change IRQ sources */
-       if (reg_esr & FLEXCAN_ESR_ALL_INT)
-               flexcan_write(reg_esr & FLEXCAN_ESR_ALL_INT, &regs->esr);
+       reg_iflag1 = flexcan_read(&regs->iflag1);
+
+       flexcan_err_irq(irq, dev);
 
        /*
         * schedule NAPI in case of:
@@ -710,18 +742,9 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
         * - state change IRQ
         * - bus error IRQ and bus error reporting is activated
         */
-       if ((reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) ||
-           (reg_esr & FLEXCAN_ESR_ERR_STATE) ||
-           flexcan_has_and_handle_berr(priv, reg_esr)) {
-               /*
-                * The error bits are cleared on read,
-                * save them for later use.
-                */
-               priv->reg_esr = reg_esr & FLEXCAN_ESR_ERR_BUS;
+       if (reg_iflag1 & FLEXCAN_IFLAG_RX_FIFO_AVAILABLE) {
                flexcan_write(FLEXCAN_IFLAG_DEFAULT &
                        ~FLEXCAN_IFLAG_RX_FIFO_AVAILABLE, &regs->imask1);
-               flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
-                      &regs->ctrl);
                napi_schedule(&priv->napi);
        }
 
@@ -944,10 +967,17 @@ static int flexcan_open(struct net_device *dev)
        if (err)
                goto out_close;
 
+       if (priv->err_irq) {
+               err = request_irq(priv->err_irq, flexcan_err_irq, IRQF_SHARED,
+                                 dev->name, dev);
+               if (err)
+                       goto out_free_irq;
+       }
+
        /* start chip and queuing */
        err = flexcan_chip_start(dev);
        if (err)
-               goto out_free_irq;
+               goto out_free_err_irq;
 
        can_led_event(dev, CAN_LED_EVENT_OPEN);
 
@@ -956,6 +986,9 @@ static int flexcan_open(struct net_device *dev)
 
        return 0;
 
+ out_free_err_irq:
+       if (priv->err_irq)
+               free_irq(priv->err_irq, dev);
  out_free_irq:
        free_irq(dev->irq, dev);
  out_close:
@@ -977,6 +1010,9 @@ static int flexcan_close(struct net_device *dev)
        flexcan_chip_stop(dev);
 
        free_irq(dev->irq, dev);
+       if (priv->err_irq)
+               free_irq(priv->err_irq, dev);
+
        clk_disable_unprepare(priv->clk_per);
        clk_disable_unprepare(priv->clk_ipg);
 
@@ -1099,7 +1135,7 @@ static int flexcan_probe(struct platform_device *pdev)
        struct resource *mem;
        struct clk *clk_ipg = NULL, *clk_per = NULL;
        void __iomem *base;
-       int err, irq;
+       int err, irq, err_irq;
        u32 clock_freq = 0;
 
        if (pdev->dev.of_node)
@@ -1126,6 +1162,10 @@ static int flexcan_probe(struct platform_device *pdev)
        if (irq <= 0)
                return -ENODEV;
 
+       err_irq = platform_get_irq(pdev, 1);
+       if (err_irq <= 0)
+               err_irq = 0;
+
        base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(base))
                return PTR_ERR(base);
@@ -1149,6 +1189,7 @@ static int flexcan_probe(struct platform_device *pdev)
        dev->flags |= IFF_ECHO;
 
        priv = netdev_priv(dev);
+       priv->err_irq = err_irq;
        priv->can.clock.freq = clock_freq;
        priv->can.bittiming_const = &flexcan_bittiming_const;
        priv->can.do_set_mode = flexcan_set_mode;
-- 
1.8.5

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