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: c045213 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
Signed-off-by: Jim Quinlan <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <[email protected]>

Author: jamesequinlan

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);