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s390/pci: PCI hotplug support via SCLP
Add SCLP PCI configure/deconfigure and implement a PCI hotplug controller (s390_pci_hpc). The hotplug controller creates a slot for every PCI function in stand-by or configured state. The PCI functions are named after the PCI function ID (fid). By writing to the power attribute in /sys/bus/pci/slots/<fid>/power the PCI function is moved to stand-by or configured state. If moved to the configured state the device is automatically scanned by the s390 PCI layer. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Jan Glauber
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Martin Schwidefsky
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Nov 30, 2012
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,252 @@ | ||
| /* | ||
| * PCI Hot Plug Controller Driver for System z | ||
| * | ||
| * Copyright 2012 IBM Corp. | ||
| * | ||
| * Author(s): | ||
| * Jan Glauber <jang@linux.vnet.ibm.com> | ||
| */ | ||
|
|
||
| #define COMPONENT "zPCI hpc" | ||
| #define pr_fmt(fmt) COMPONENT ": " fmt | ||
|
|
||
| #include <linux/module.h> | ||
| #include <linux/kernel.h> | ||
| #include <linux/slab.h> | ||
| #include <linux/pci.h> | ||
| #include <linux/pci_hotplug.h> | ||
| #include <linux/init.h> | ||
| #include <asm/sclp.h> | ||
|
|
||
| #define SLOT_NAME_SIZE 10 | ||
| static LIST_HEAD(s390_hotplug_slot_list); | ||
|
|
||
| MODULE_AUTHOR("Jan Glauber <jang@linux.vnet.ibm.com"); | ||
| MODULE_DESCRIPTION("Hot Plug PCI Controller for System z"); | ||
| MODULE_LICENSE("GPL"); | ||
|
|
||
| static int zpci_fn_configured(enum zpci_state state) | ||
| { | ||
| return state == ZPCI_FN_STATE_CONFIGURED || | ||
| state == ZPCI_FN_STATE_ONLINE; | ||
| } | ||
|
|
||
| /* | ||
| * struct slot - slot information for each *physical* slot | ||
| */ | ||
| struct slot { | ||
| struct list_head slot_list; | ||
| struct hotplug_slot *hotplug_slot; | ||
| struct zpci_dev *zdev; | ||
| }; | ||
|
|
||
| static int enable_slot(struct hotplug_slot *hotplug_slot) | ||
| { | ||
| struct slot *slot = hotplug_slot->private; | ||
| int rc; | ||
|
|
||
| if (slot->zdev->state != ZPCI_FN_STATE_STANDBY) | ||
| return -EIO; | ||
|
|
||
| rc = sclp_pci_configure(slot->zdev->fid); | ||
| if (!rc) { | ||
| slot->zdev->state = ZPCI_FN_STATE_CONFIGURED; | ||
| /* automatically scan the device after is was configured */ | ||
| zpci_enable_device(slot->zdev); | ||
| zpci_scan_device(slot->zdev); | ||
| } | ||
| return rc; | ||
| } | ||
|
|
||
| static int disable_slot(struct hotplug_slot *hotplug_slot) | ||
| { | ||
| struct slot *slot = hotplug_slot->private; | ||
| int rc; | ||
|
|
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| if (!zpci_fn_configured(slot->zdev->state)) | ||
| return -EIO; | ||
|
|
||
| /* TODO: we rely on the user to unbind/remove the device, is that plausible | ||
| * or do we need to trigger that here? | ||
| */ | ||
| rc = sclp_pci_deconfigure(slot->zdev->fid); | ||
| if (!rc) { | ||
| /* Fixme: better call List-PCI to find the disabled FH | ||
| for the FID since the FH should be opaque... */ | ||
| slot->zdev->fh &= 0x7fffffff; | ||
| slot->zdev->state = ZPCI_FN_STATE_STANDBY; | ||
| } | ||
| return rc; | ||
| } | ||
|
|
||
| static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value) | ||
| { | ||
| struct slot *slot = hotplug_slot->private; | ||
|
|
||
| switch (slot->zdev->state) { | ||
| case ZPCI_FN_STATE_STANDBY: | ||
| *value = 0; | ||
| break; | ||
| default: | ||
| *value = 1; | ||
| break; | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value) | ||
| { | ||
| /* if the slot exits it always contains a function */ | ||
| *value = 1; | ||
| return 0; | ||
| } | ||
|
|
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| static void release_slot(struct hotplug_slot *hotplug_slot) | ||
| { | ||
| struct slot *slot = hotplug_slot->private; | ||
|
|
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| pr_debug("%s - physical_slot = %s\n", __func__, hotplug_slot_name(hotplug_slot)); | ||
| kfree(slot->hotplug_slot->info); | ||
| kfree(slot->hotplug_slot); | ||
| kfree(slot); | ||
| } | ||
|
|
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| static struct hotplug_slot_ops s390_hotplug_slot_ops = { | ||
| .enable_slot = enable_slot, | ||
| .disable_slot = disable_slot, | ||
| .get_power_status = get_power_status, | ||
| .get_adapter_status = get_adapter_status, | ||
| }; | ||
|
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| static int init_pci_slot(struct zpci_dev *zdev) | ||
| { | ||
| struct hotplug_slot *hotplug_slot; | ||
| struct hotplug_slot_info *info; | ||
| char name[SLOT_NAME_SIZE]; | ||
| struct slot *slot; | ||
| int rc; | ||
|
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| if (!zdev) | ||
| return 0; | ||
|
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| slot = kzalloc(sizeof(*slot), GFP_KERNEL); | ||
| if (!slot) | ||
| goto error; | ||
|
|
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| hotplug_slot = kzalloc(sizeof(*hotplug_slot), GFP_KERNEL); | ||
| if (!hotplug_slot) | ||
| goto error_hp; | ||
| hotplug_slot->private = slot; | ||
|
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| slot->hotplug_slot = hotplug_slot; | ||
| slot->zdev = zdev; | ||
|
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| info = kzalloc(sizeof(*info), GFP_KERNEL); | ||
| if (!info) | ||
| goto error_info; | ||
| hotplug_slot->info = info; | ||
|
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| hotplug_slot->ops = &s390_hotplug_slot_ops; | ||
| hotplug_slot->release = &release_slot; | ||
|
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| get_power_status(hotplug_slot, &info->power_status); | ||
| get_adapter_status(hotplug_slot, &info->adapter_status); | ||
|
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| snprintf(name, SLOT_NAME_SIZE, "%08x", zdev->fid); | ||
| rc = pci_hp_register(slot->hotplug_slot, zdev->bus, | ||
| ZPCI_DEVFN, name); | ||
| if (rc) { | ||
| pr_err("pci_hp_register failed with error %d\n", rc); | ||
| goto error_reg; | ||
| } | ||
| list_add(&slot->slot_list, &s390_hotplug_slot_list); | ||
| return 0; | ||
|
|
||
| error_reg: | ||
| kfree(info); | ||
| error_info: | ||
| kfree(hotplug_slot); | ||
| error_hp: | ||
| kfree(slot); | ||
| error: | ||
| return -ENOMEM; | ||
| } | ||
|
|
||
| static int __init init_pci_slots(void) | ||
| { | ||
| struct zpci_dev *zdev; | ||
| int device = 0; | ||
|
|
||
| /* | ||
| * Create a structure for each slot, and register that slot | ||
| * with the pci_hotplug subsystem. | ||
| */ | ||
| mutex_lock(&zpci_list_lock); | ||
| list_for_each_entry(zdev, &zpci_list, entry) { | ||
| init_pci_slot(zdev); | ||
| device++; | ||
| } | ||
|
|
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| mutex_unlock(&zpci_list_lock); | ||
| return (device) ? 0 : -ENODEV; | ||
| } | ||
|
|
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| static void exit_pci_slot(struct zpci_dev *zdev) | ||
| { | ||
| struct list_head *tmp, *n; | ||
| struct slot *slot; | ||
|
|
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| list_for_each_safe(tmp, n, &s390_hotplug_slot_list) { | ||
| slot = list_entry(tmp, struct slot, slot_list); | ||
| if (slot->zdev != zdev) | ||
| continue; | ||
| list_del(&slot->slot_list); | ||
| pci_hp_deregister(slot->hotplug_slot); | ||
| } | ||
| } | ||
|
|
||
| static void __exit exit_pci_slots(void) | ||
| { | ||
| struct list_head *tmp, *n; | ||
| struct slot *slot; | ||
|
|
||
| /* | ||
| * Unregister all of our slots with the pci_hotplug subsystem. | ||
| * Memory will be freed in release_slot() callback after slot's | ||
| * lifespan is finished. | ||
| */ | ||
| list_for_each_safe(tmp, n, &s390_hotplug_slot_list) { | ||
| slot = list_entry(tmp, struct slot, slot_list); | ||
| list_del(&slot->slot_list); | ||
| pci_hp_deregister(slot->hotplug_slot); | ||
| } | ||
| } | ||
|
|
||
| static int __init pci_hotplug_s390_init(void) | ||
| { | ||
| /* | ||
| * Do specific initialization stuff for your driver here | ||
| * like initializing your controller hardware (if any) and | ||
| * determining the number of slots you have in the system | ||
| * right now. | ||
| */ | ||
|
|
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| if (!pci_probe) | ||
| return -EOPNOTSUPP; | ||
|
|
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| /* register callbacks for slot handling from arch code */ | ||
| mutex_lock(&zpci_list_lock); | ||
| hotplug_ops.create_slot = init_pci_slot; | ||
| hotplug_ops.remove_slot = exit_pci_slot; | ||
| mutex_unlock(&zpci_list_lock); | ||
| pr_info("registered hotplug slot callbacks\n"); | ||
| return init_pci_slots(); | ||
| } | ||
|
|
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| static void __exit pci_hotplug_s390_exit(void) | ||
| { | ||
| exit_pci_slots(); | ||
| } | ||
|
|
||
| module_init(pci_hotplug_s390_init); | ||
| module_exit(pci_hotplug_s390_exit); |
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