Fixed MTP to work with TWRP

drivers/pci/hotplug/pciehp_acpi.c

@@ -0,0 +1,137 @@
+/*
+ * ACPI related functions for PCI Express Hot Plug driver.
+ *
+ * Copyright (C) 2008 Kenji Kaneshige
+ * Copyright (C) 2008 Fujitsu Limited.
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "pciehp.h"
+
+#define PCIEHP_DETECT_PCIE	(0)
+#define PCIEHP_DETECT_ACPI	(1)
+#define PCIEHP_DETECT_AUTO	(2)
+#define PCIEHP_DETECT_DEFAULT	PCIEHP_DETECT_AUTO
+
+struct dummy_slot {
+	u32 number;
+	struct list_head list;
+};
+
+static int slot_detection_mode;
+static char *pciehp_detect_mode;
+module_param(pciehp_detect_mode, charp, 0444);
+MODULE_PARM_DESC(pciehp_detect_mode,
+	 "Slot detection mode: pcie, acpi, auto\n"
+	 "  pcie          - Use PCIe based slot detection\n"
+	 "  acpi          - Use ACPI for slot detection\n"
+	 "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
+	 "                  slot ids are found. Otherwise, use pcie option\n");
+
+int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
+{
+	if (slot_detection_mode != PCIEHP_DETECT_ACPI)
+		return 0;
+	if (acpi_pci_detect_ejectable(ACPI_HANDLE(&dev->dev)))
+		return 0;
+	return -ENODEV;
+}
+
+static int __init parse_detect_mode(void)
+{
+	if (!pciehp_detect_mode)
+		return PCIEHP_DETECT_DEFAULT;
+	if (!strcmp(pciehp_detect_mode, "pcie"))
+		return PCIEHP_DETECT_PCIE;
+	if (!strcmp(pciehp_detect_mode, "acpi"))
+		return PCIEHP_DETECT_ACPI;
+	if (!strcmp(pciehp_detect_mode, "auto"))
+		return PCIEHP_DETECT_AUTO;
+	warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
+	     pciehp_detect_mode);
+	return PCIEHP_DETECT_DEFAULT;
+}
+
+static int __initdata dup_slot_id;
+static int __initdata acpi_slot_detected;
+static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
+
+/* Dummy driver for duplicate name detection */
+static int __init dummy_probe(struct pcie_device *dev)
+{
+	u32 slot_cap;
+	acpi_handle handle;
+	struct dummy_slot *slot, *tmp;
+	struct pci_dev *pdev = dev->port;
+
+	pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
+	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
+	if (!slot)
+		return -ENOMEM;
+	slot->number = (slot_cap & PCI_EXP_SLTCAP_PSN) >> 19;
+	list_for_each_entry(tmp, &dummy_slots, list) {
+		if (tmp->number == slot->number)
+			dup_slot_id++;
+	}
+	list_add_tail(&slot->list, &dummy_slots);
+	handle = ACPI_HANDLE(&pdev->dev);
+	if (!acpi_slot_detected && acpi_pci_detect_ejectable(handle))
+		acpi_slot_detected = 1;
+	return -ENODEV;         /* dummy driver always returns error */
+}
+
+static struct pcie_port_service_driver __initdata dummy_driver = {
+	.name		= "pciehp_dummy",
+	.port_type	= PCIE_ANY_PORT,
+	.service	= PCIE_PORT_SERVICE_HP,
+	.probe		= dummy_probe,
+};
+
+static int __init select_detection_mode(void)
+{
+	struct dummy_slot *slot, *tmp;
+
+	if (pcie_port_service_register(&dummy_driver))
+		return PCIEHP_DETECT_ACPI;
+	pcie_port_service_unregister(&dummy_driver);
+	list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
+		list_del(&slot->list);
+		kfree(slot);
+	}
+	if (acpi_slot_detected && dup_slot_id)
+		return PCIEHP_DETECT_ACPI;
+	return PCIEHP_DETECT_PCIE;
+}
+
+void __init pciehp_acpi_slot_detection_init(void)
+{
+	slot_detection_mode = parse_detect_mode();
+	if (slot_detection_mode != PCIEHP_DETECT_AUTO)
+		goto out;
+	slot_detection_mode = select_detection_mode();
+out:
+	if (slot_detection_mode == PCIEHP_DETECT_ACPI)
+		info("Using ACPI for slot detection.\n");
+}