can: kvaser_pciefd: Force IRQ edge in case of nested IRQ

Avoid the driver missing IRQs by temporarily masking IRQs in the ISR
to enforce an edge even if a different IRQ is signalled before handled
IRQs are cleared.

Fixes: 48f827d4f48f ("can: kvaser_pciefd: Move reset of DMA RX buffers to the end of the ISR")
Cc: stable@vger.kernel.org
Signed-off-by: Axel Forsman <axfo@kvaser.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Reviewed-by: Jimmy Assarsson <extja@kvaser.com>
Link: https://patch.msgid.link/20250520114332.8961-2-axfo@kvaser.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/kvaser_pciefd.c b/drivers/net/can/kvaser_pciefd.c
index cf0d518..9cc9176 100644 (file)
--- a/drivers/net/can/kvaser_pciefd.c
+++ b/drivers/net/can/kvaser_pciefd.c
@@ -1646,24 +1646,28 @@ static int kvaser_pciefd_read_buffer(struct kvaser_pciefd *pcie, int dma_buf)
        return res;
 }
 
-static u32 kvaser_pciefd_receive_irq(struct kvaser_pciefd *pcie)
+static void kvaser_pciefd_receive_irq(struct kvaser_pciefd *pcie)
 {
+       void __iomem *srb_cmd_reg = KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG;
        u32 irq = ioread32(KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_IRQ_REG);
 
-       if (irq & KVASER_PCIEFD_SRB_IRQ_DPD0)
+       iowrite32(irq, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_IRQ_REG);
+
+       if (irq & KVASER_PCIEFD_SRB_IRQ_DPD0) {
                kvaser_pciefd_read_buffer(pcie, 0);
+               iowrite32(KVASER_PCIEFD_SRB_CMD_RDB0, srb_cmd_reg); /* Rearm buffer */
+       }
 
-       if (irq & KVASER_PCIEFD_SRB_IRQ_DPD1)
+       if (irq & KVASER_PCIEFD_SRB_IRQ_DPD1) {
                kvaser_pciefd_read_buffer(pcie, 1);
+               iowrite32(KVASER_PCIEFD_SRB_CMD_RDB1, srb_cmd_reg); /* Rearm buffer */
+       }
 
        if (unlikely(irq & KVASER_PCIEFD_SRB_IRQ_DOF0 ||
                     irq & KVASER_PCIEFD_SRB_IRQ_DOF1 ||
                     irq & KVASER_PCIEFD_SRB_IRQ_DUF0 ||
                     irq & KVASER_PCIEFD_SRB_IRQ_DUF1))
                dev_err(&pcie->pci->dev, "DMA IRQ error 0x%08X\n", irq);
-
-       iowrite32(irq, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_IRQ_REG);
-       return irq;
 }
 
 static void kvaser_pciefd_transmit_irq(struct kvaser_pciefd_can *can)
@@ -1691,29 +1695,22 @@ static irqreturn_t kvaser_pciefd_irq_handler(int irq, void *dev)
        struct kvaser_pciefd *pcie = (struct kvaser_pciefd *)dev;
        const struct kvaser_pciefd_irq_mask *irq_mask = pcie->driver_data->irq_mask;
        u32 pci_irq = ioread32(KVASER_PCIEFD_PCI_IRQ_ADDR(pcie));
-       u32 srb_irq = 0;
-       u32 srb_release = 0;
        int i;
 
        if (!(pci_irq & irq_mask->all))
                return IRQ_NONE;
 
+       iowrite32(0, KVASER_PCIEFD_PCI_IEN_ADDR(pcie));
+
        if (pci_irq & irq_mask->kcan_rx0)
-               srb_irq = kvaser_pciefd_receive_irq(pcie);
+               kvaser_pciefd_receive_irq(pcie);
 
        for (i = 0; i < pcie->nr_channels; i++) {
                if (pci_irq & irq_mask->kcan_tx[i])
                        kvaser_pciefd_transmit_irq(pcie->can[i]);
        }
 
-       if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD0)
-               srb_release |= KVASER_PCIEFD_SRB_CMD_RDB0;
-
-       if (srb_irq & KVASER_PCIEFD_SRB_IRQ_DPD1)
-               srb_release |= KVASER_PCIEFD_SRB_CMD_RDB1;
-
-       if (srb_release)
-               iowrite32(srb_release, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG);
+       iowrite32(irq_mask->all, KVASER_PCIEFD_PCI_IEN_ADDR(pcie));
 
        return IRQ_HANDLED;
 }
@@ -1733,13 +1730,22 @@ static void kvaser_pciefd_teardown_can_ctrls(struct kvaser_pciefd *pcie)
        }
 }
 
+static void kvaser_pciefd_disable_irq_srcs(struct kvaser_pciefd *pcie)
+{
+       unsigned int i;
+
+       /* Masking PCI_IRQ is insufficient as running ISR will unmask it */
+       iowrite32(0, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_IEN_REG);
+       for (i = 0; i < pcie->nr_channels; ++i)
+               iowrite32(0, pcie->can[i]->reg_base + KVASER_PCIEFD_KCAN_IEN_REG);
+}
+
 static int kvaser_pciefd_probe(struct pci_dev *pdev,
                               const struct pci_device_id *id)
 {
        int ret;
        struct kvaser_pciefd *pcie;
        const struct kvaser_pciefd_irq_mask *irq_mask;
-       void __iomem *irq_en_base;
 
        pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
        if (!pcie)
@@ -1805,8 +1811,7 @@ static int kvaser_pciefd_probe(struct pci_dev *pdev,
                  KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_IEN_REG);
 
        /* Enable PCI interrupts */
-       irq_en_base = KVASER_PCIEFD_PCI_IEN_ADDR(pcie);
-       iowrite32(irq_mask->all, irq_en_base);
+       iowrite32(irq_mask->all, KVASER_PCIEFD_PCI_IEN_ADDR(pcie));
        /* Ready the DMA buffers */
        iowrite32(KVASER_PCIEFD_SRB_CMD_RDB0,
                  KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CMD_REG);
@@ -1820,8 +1825,7 @@ static int kvaser_pciefd_probe(struct pci_dev *pdev,
        return 0;
 
 err_free_irq:
-       /* Disable PCI interrupts */
-       iowrite32(0, irq_en_base);
+       kvaser_pciefd_disable_irq_srcs(pcie);
        free_irq(pcie->pci->irq, pcie);
 
 err_pci_free_irq_vectors:
@@ -1844,35 +1848,26 @@ err_disable_pci:
        return ret;
 }
 
-static void kvaser_pciefd_remove_all_ctrls(struct kvaser_pciefd *pcie)
-{
-       int i;
-
-       for (i = 0; i < pcie->nr_channels; i++) {
-               struct kvaser_pciefd_can *can = pcie->can[i];
-
-               if (can) {
-                       iowrite32(0, can->reg_base + KVASER_PCIEFD_KCAN_IEN_REG);
-                       unregister_candev(can->can.dev);
-                       timer_delete(&can->bec_poll_timer);
-                       kvaser_pciefd_pwm_stop(can);
-                       free_candev(can->can.dev);
-               }
-       }
-}
-
 static void kvaser_pciefd_remove(struct pci_dev *pdev)
 {
        struct kvaser_pciefd *pcie = pci_get_drvdata(pdev);
+       unsigned int i;
 
-       kvaser_pciefd_remove_all_ctrls(pcie);
+       for (i = 0; i < pcie->nr_channels; ++i) {
+               struct kvaser_pciefd_can *can = pcie->can[i];
 
-       /* Disable interrupts */
-       iowrite32(0, KVASER_PCIEFD_SRB_ADDR(pcie) + KVASER_PCIEFD_SRB_CTRL_REG);
-       iowrite32(0, KVASER_PCIEFD_PCI_IEN_ADDR(pcie));
+               unregister_candev(can->can.dev);
+               timer_delete(&can->bec_poll_timer);
+               kvaser_pciefd_pwm_stop(can);
+       }
 
+       kvaser_pciefd_disable_irq_srcs(pcie);
        free_irq(pcie->pci->irq, pcie);
        pci_free_irq_vectors(pcie->pci);
+
+       for (i = 0; i < pcie->nr_channels; ++i)
+               free_candev(pcie->can[i]->can.dev);
+
        pci_iounmap(pdev, pcie->reg_base);
        pci_release_regions(pdev);
        pci_disable_device(pdev);