PCI: add quirk for Gateworks PLX PEX860x switch with GPIO PERST#

Gateworks boards use PLX PEX860x switches where downstream ports
have their PERST# driven from the PEX GPIO.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>

drivers/pci/quirks.c

@@ -26,6 +26,7 @@
 #include <linux/sched.h>
 #include <linux/ktime.h>
 #include <linux/mm.h>
+#include <linux/of.h>
 #include <linux/platform_data/x86/apple.h>
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
 #include "pci.h"
@@ -4815,3 +4816,34 @@ static void quirk_no_ats(struct pci_dev *pdev)
 /* AMD Stoney platform GPU */
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_no_ats);
 #endif /* CONFIG_PCI_ATS */
+
+#ifdef CONFIG_PCI_HOST_THUNDER_PEM
+/*
+ * fixup for PLX PEX8909 bridge to configure GPIO1-7 as output High
+ * as they are used for slots1-7 PERST#
+ */
+static void newport_pciesw_early_fixup(struct pci_dev *dev)
+{
+	u32 dw;
+
+	if (!of_machine_is_compatible("gw,newport"))
+		return;
+
+	if (dev->devfn != 0)
+		return;
+
+	dev_info(&dev->dev, "de-asserting PERST#\n");
+	pci_read_config_dword(dev, 0x62c, &dw);
+	dw |= 0xaaa8; /* GPIO1-7 outputs */
+	pci_write_config_dword(dev, 0x62c, dw);
+
+	pci_read_config_dword(dev, 0x644, &dw);
+	dw |= 0xfe;   /* GPIO1-7 output high */
+	pci_write_config_dword(dev, 0x644, dw);
+
+	msleep(100);
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8609, newport_pciesw_early_fixup);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8606, newport_pciesw_early_fixup);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8604, newport_pciesw_early_fixup);
+#endif /* CONFIG_PCI_HOST_THUNDER_PEM */