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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /drivers/pci/hotplug/acpi_pcihp.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/pci/hotplug/acpi_pcihp.c')
-rw-r--r--drivers/pci/hotplug/acpi_pcihp.c212
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..2750a64ce
--- /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
+ * @pdev: 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");