[PATCH v2] PCI: dwc: Round up num_ctrls if num_vectors is less than MAX_MSI_IRQS_PER_CTRL

[Shawn Lin]

Some SoCs may only support 1 RC with a few MSIs support that the total numver of MSIs is
less than MAX_MSI_IRQS_PER_CTRL. In this case, num_ctrls will be zero which fails setting
up MSI support. Fix it by rounding up num_ctrls to at least one.

Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
---

Changes in v2:
- set num_ctrls to 1 if it's less than one

 drivers/pci/controller/dwc/pcie-designware-host.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 39f3b37..5c2229f 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -62,6 +62,8 @@ irqreturn_t dw_handle_msi_irq(struct dw_pcie_rp *pp)
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 
 	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+	if (num_ctrls < 1)
+		num_ctrls = 1
 
 	for (i = 0; i < num_ctrls; i++) {
 		status = dw_pcie_readl_dbi(pci, PCIE_MSI_INTR0_STATUS +
@@ -343,6 +345,8 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp)
 	if (!pp->num_vectors)
 		pp->num_vectors = MSI_DEF_NUM_VECTORS;
 	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+	if (num_ctrls < 1)
+		num_ctrls = 1
 
 	if (!pp->msi_irq[0]) {
 		pp->msi_irq[0] = platform_get_irq_byname_optional(pdev, "msi");
@@ -707,6 +711,8 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 
 	if (pp->has_msi_ctrl) {
 		num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+		if (num_ctrls < 1)
+			num_ctrls = 1
 
 		/* Initialize IRQ Status array */
 		for (ctrl = 0; ctrl < num_ctrls; ctrl++) {
-- 
2.7.4