1 files changed, 68 insertions, 0 deletions

diff --git a/arch/sh/drivers/pci/fixups-sdk7786.c b/arch/sh/drivers/pci/fixups-sdk7786.c
new file mode 100644
index 000000000000..058a65a1aa20
--- /dev/null
+++ b/arch/sh/drivers/pci/fixups-sdk7786.c
@@ -0,0 +1,68 @@
+/*
+ * SDK7786 FPGA PCIe mux handling
+ *
+ * Copyright (C) 2010  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#define pr_fmt(fmt) "PCI: " fmt
+
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <mach/fpga.h>
+
+/*
+ * The SDK7786 FPGA supports mangling of most of the slots in some way or
+ * another. Slots 3/4 are special in that only one can be supported at a
+ * time, and both appear on port 3 to the PCI bus scan. Enabling slot 4
+ * (the horizontal edge connector) will disable slot 3 entirely.
+ *
+ * Misconfigurations can be detected through the FPGA via the slot
+ * resistors to determine card presence. Hotplug remains unsupported.
+ */
+static unsigned int slot4en __devinitdata;
+
+char *__devinit pcibios_setup(char *str)
+{
+        if (strcmp(str, "slot4en") == 0) {
+                slot4en = 1;
+                return NULL;
+        }
+
+        return str;
+}
+
+static int __init sdk7786_pci_init(void)
+{
+        u16 data = fpga_read_reg(PCIECR);
+
+        /*
+         * Enable slot #4 if it's been specified on the command line.
+         *
+         * Optionally reroute if slot #4 has a card present while slot #3
+         * does not, regardless of command line value.
+         *
+         * Card presence is logically inverted.
+         */
+        slot4en ?: (!(data & PCIECR_PRST4) && (data & PCIECR_PRST3));
+        if (slot4en) {
+                pr_info("Activating PCIe slot#4 (disabling slot#3)\n");
+
+                data &= ~PCIECR_PCIEMUX1;
+                fpga_write_reg(data, PCIECR);
+
+                /* Warn about forced rerouting if slot#3 is occupied */
+                if ((data & PCIECR_PRST3) == 0) {
+                        pr_warning("Unreachable card detected in slot#3\n");
+                        return -EBUSY;
+                }
+        } else
+                pr_info("PCIe slot#4 disabled\n");
+
+        return 0;
+}
+postcore_initcall(sdk7786_pci_init);