[PATCH] PCI: dwc: Reject a negative nr_irqs value in dw_pcie_edma_irq_verify()

[Niklas Cassel <cassel@kernel.org>]

Platforms that do not have (one or more) dedicated IRQs for the eDMA
need to set nr_irqs to a non-zero value in their DWC glue driver.

Platforms that do have (one or more) dedicated IRQs do not need to
initialize nr_irqs. DWC common code will automatically set nr_irqs.

Since a glue driver can initialize nr_irqs, dw_pcie_edma_irq_verify()
should verify that nr_irqs, if non-zero, is a valid value. Thus, add a
check in dw_pcie_edma_irq_verify() to reject a negative nr_irqs value.

This fixes the following build warning when compiling with W=1:

drivers/pci/controller/dwc/pcie-designware.c: In function ‘dw_pcie_edma_detect’:
drivers/pci/controller/dwc/pcie-designware.c:989:50: warning: ‘%d’ directive output may be truncated writing between 1 and 11 bytes into a region of size 3 [-Wformat-truncation=]
  989 |                 snprintf(name, sizeof(name), "dma%d", pci->edma.nr_irqs);
      |                                                  ^~

Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/pci/controller/dwc/pcie-designware.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 3c683b6119c3..d7f695d5dbc4 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -978,6 +978,8 @@ static int dw_pcie_edma_irq_verify(struct dw_pcie *pci)
 		return 0;
 	else if (pci->edma.nr_irqs > 1)
 		return pci->edma.nr_irqs != ch_cnt ? -EINVAL : 0;
+	else if (pci->edma.nr_irqs < 0)
+		return -EINVAL;
 
 	ret = platform_get_irq_byname_optional(pdev, "dma");
 	if (ret > 0) {
-- 
2.47.1