1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
new file mode 100644
index 000000000..6b7c1ed58
--- /dev/null
+++ b/drivers/pci/hotplug/acpi_pcihp.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Common ACPI functions for hot plug platforms
+ *
+ * Copyright (C) 2006 Intel Corporation
+ *
+ * All rights reserved.
+ *
+ * Send feedback to <kristen.c.accardi@intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+#include <linux/acpi.h>
+#include <linux/pci-acpi.h>
+#include <linux/slab.h>
+
+#define MY_NAME	"acpi_pcihp"
+
+#define dbg(fmt, arg...) do { if (debug_acpi) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0)
+#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
+#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
+#define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)
+
+#define	METHOD_NAME__SUN	"_SUN"
+#define	METHOD_NAME_OSHP	"OSHP"
+
+static bool debug_acpi;
+
+/* acpi_run_oshp - get control of hotplug from the firmware
+ *
+ * @handle - the handle of the hotplug controller.
+ */
+static acpi_status acpi_run_oshp(acpi_handle handle)
+{
+	acpi_status		status;
+	struct acpi_buffer	string = { ACPI_ALLOCATE_BUFFER, NULL };
+
+	acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
+
+	/* run OSHP */
+	status = acpi_evaluate_object(handle, METHOD_NAME_OSHP, NULL, NULL);
+	if (ACPI_FAILURE(status))
+		if (status != AE_NOT_FOUND)
+			printk(KERN_ERR "%s:%s OSHP fails=0x%x\n",
+			       __func__, (char *)string.pointer, status);
+		else
+			dbg("%s:%s OSHP not found\n",
+			    __func__, (char *)string.pointer);
+	else
+		pr_debug("%s:%s OSHP passes\n", __func__,
+			(char *)string.pointer);
+
+	kfree(string.pointer);
+	return status;
+}
+
+/**
+ * acpi_get_hp_hw_control_from_firmware
+ * @dev: the pci_dev of the bridge that has a hotplug controller
+ *
+ * Attempt to take hotplug control from firmware.
+ */
+int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev)
+{
+	const struct pci_host_bridge *host;
+	const struct acpi_pci_root *root;
+	acpi_status status;
+	acpi_handle chandle, handle;
+	struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };
+
+	/*
+	 * If there's no ACPI host bridge (i.e., ACPI support is compiled
+	 * into the kernel but the hardware platform doesn't support ACPI),
+	 * there's nothing to do here.
+	 */
+	host = pci_find_host_bridge(pdev->bus);
+	root = acpi_pci_find_root(ACPI_HANDLE(&host->dev));
+	if (!root)
+		return 0;
+
+	/*
+	 * If _OSC exists, it determines whether we're allowed to manage
+	 * the SHPC.  We executed it while enumerating the host bridge.
+	 */
+	if (root->osc_support_set) {
+		if (host->native_shpc_hotplug)
+			return 0;
+		return -ENODEV;
+	}
+
+	/*
+	 * In the absence of _OSC, we're always allowed to manage the SHPC.
+	 * However, if an OSHP method is present, we must execute it so the
+	 * firmware can transfer control to the OS, e.g., direct interrupts
+	 * to the OS instead of to the firmware.
+	 *
+	 * N.B. The PCI Firmware Spec (r3.2, sec 4.8) does not endorse
+	 * searching up the ACPI hierarchy, so the loops below are suspect.
+	 */
+	handle = ACPI_HANDLE(&pdev->dev);
+	if (!handle) {
+		/*
+		 * This hotplug controller was not listed in the ACPI name
+		 * space at all. Try to get ACPI handle of parent PCI bus.
+		 */
+		struct pci_bus *pbus;
+		for (pbus = pdev->bus; pbus; pbus = pbus->parent) {
+			handle = acpi_pci_get_bridge_handle(pbus);
+			if (handle)
+				break;
+		}
+	}
+
+	while (handle) {
+		acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
+		pci_info(pdev, "Requesting control of SHPC hotplug via OSHP (%s)\n",
+			 (char *)string.pointer);
+		status = acpi_run_oshp(handle);
+		if (ACPI_SUCCESS(status))
+			goto got_one;
+		if (acpi_is_root_bridge(handle))
+			break;
+		chandle = handle;
+		status = acpi_get_parent(chandle, &handle);
+		if (ACPI_FAILURE(status))
+			break;
+	}
+
+	pci_info(pdev, "Cannot get control of SHPC hotplug\n");
+	kfree(string.pointer);
+	return -ENODEV;
+got_one:
+	pci_info(pdev, "Gained control of SHPC hotplug (%s)\n",
+		 (char *)string.pointer);
+	kfree(string.pointer);
+	return 0;
+}
+EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
+
+static int pcihp_is_ejectable(acpi_handle handle)
+{
+	acpi_status status;
+	unsigned long long removable;
+	if (!acpi_has_method(handle, "_ADR"))
+		return 0;
+	if (acpi_has_method(handle, "_EJ0"))
+		return 1;
+	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
+	if (ACPI_SUCCESS(status) && removable)
+		return 1;
+	return 0;
+}
+
+/**
+ * acpi_pcihp_check_ejectable - check if handle is ejectable ACPI PCI slot
+ * @pbus: the PCI bus of the PCI slot corresponding to 'handle'
+ * @handle: ACPI handle to check
+ *
+ * Return 1 if handle is ejectable PCI slot, 0 otherwise.
+ */
+int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle)
+{
+	acpi_handle bridge_handle, parent_handle;
+
+	bridge_handle = acpi_pci_get_bridge_handle(pbus);
+	if (!bridge_handle)
+		return 0;
+	if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle))))
+		return 0;
+	if (bridge_handle != parent_handle)
+		return 0;
+	return pcihp_is_ejectable(handle);
+}
+EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable);
+
+static acpi_status
+check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	int *found = (int *)context;
+	if (pcihp_is_ejectable(handle)) {
+		*found = 1;
+		return AE_CTRL_TERMINATE;
+	}
+	return AE_OK;
+}
+
+/**
+ * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots
+ * @handle - handle of the PCI bus to scan
+ *
+ * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise.
+ */
+int acpi_pci_detect_ejectable(acpi_handle handle)
+{
+	int found = 0;
+
+	if (!handle)
+		return found;
+
+	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+			    check_hotplug, NULL, (void *)&found, NULL);
+	return found;
+}
+EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable);
+
+module_param(debug_acpi, bool, 0644);
+MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not");