PCI: dwc: Add start_link/stop_link inlines

Factor out this pattern:

  if (!pci->ops || !pci->ops->start_link)
    return -EINVAL;

  return pci->ops->start_link(pci);

into a new dw_pcie_start_link() wrapper and do the same for the stop_link()
method.

Note that dw_pcie_ep_start() previously returned -EINVAL if there was no
platform start_link() method, which didn't make much sense since that is
not an error.  It will now return 0 in that case.

As a side-effect, drop the empty start_link() and dummy dw_pcie_ops
instances from the generic DW PCIe and Layerscape EP platform drivers.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-14-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 7d6e9b7576be..8ba239292634 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -365,6 +365,20 @@ static inline void dw_pcie_dbi_ro_wr_dis(struct dw_pcie *pci)
 	dw_pcie_writel_dbi(pci, reg, val);
 }
 
+static inline int dw_pcie_start_link(struct dw_pcie *pci)
+{
+	if (pci->ops && pci->ops->start_link)
+		return pci->ops->start_link(pci);
+
+	return 0;
+}
+
+static inline void dw_pcie_stop_link(struct dw_pcie *pci)
+{
+	if (pci->ops && pci->ops->stop_link)
+		pci->ops->stop_link(pci);
+}
+
 #ifdef CONFIG_PCIE_DW_HOST
 irqreturn_t dw_handle_msi_irq(struct pcie_port *pp);
 void dw_pcie_setup_rc(struct pcie_port *pp);