PCI: brcmstb: Use internal register to change link capability

The driver has been mistakenly writing to a read-only (RO)
configuration space register (PCI_EXP_LNKCAP) to change the
PCIe link capability.

Although harmless in this case, the proper write destination
is an internal register that is reflected by PCI_EXP_LNKCAP.

Thus, fix the brcm_pcie_set_gen() function to correctly update
the link capability.

Fixes: c0452137034b ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250214173944.47506-3-james.quinlan@broadcom.com
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 2f1b2a4fe540670fc3d85f58b5482ca82500db56..cabbf7fbb8eb222ec14083cdeeb856c4fd3f90b3 100644 (file)
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -413,10 +413,10 @@ static int brcm_pcie_set_ssc(struct brcm_pcie *pcie)
 static void brcm_pcie_set_gen(struct brcm_pcie *pcie, int gen)
 {
        u16 lnkctl2 = readw(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);
-       u32 lnkcap = readl(pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+       u32 lnkcap = readl(pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
        lnkcap = (lnkcap & ~PCI_EXP_LNKCAP_SLS) | gen;
-       writel(lnkcap, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCAP);
+       writel(lnkcap, pcie->base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
        lnkctl2 = (lnkctl2 & ~0xf) | gen;
        writew(lnkctl2, pcie->base + BRCM_PCIE_CAP_REGS + PCI_EXP_LNKCTL2);