Re: [PATCH v7 50/50] PCI/hotplug: PowerPC PowerNV PCI hotplug driver

Gavin Shan
2015-11-23T23:17:28Z

On Wed, Nov 18, 2015 at 06:33:08PM +1100, Alexey Kardashevskiy wrote:
>On 11/05/2015 12:12 AM, Gavin Shan wrote:
>>This adds standalone driver to support PCI hotplug for PowerPC PowerNV
>>platform that runs on top of skiboot firmware. The firmware identifies
>>hotpluggable slots and marked their device tree node with proper
>>"ibm,slot-pluggable" and "ibm,reset-by-firmware". The driver scans device
>>tree nodes to create/register PCI hotplug slot accordingly.
>>
>>If the skiboot firmware doesn't support slot status retrieval, the PCI
>>slot device node shouldn't have property "ibm,reset-by-firmware". In
>>that case, none of valid PCI slots will be detected from device tree.
>>The skiboot firmware doesn't export the capability to access attention
>>LEDs yet and it's something for TBD.
>
>
>Few words what we are actually dealing with and how children slots can be
>hotplugged to parent slots?
>

Sure, will do. All comments you gave will be reflected in next revision.
Please let me know if you finish the review and I can start the respin
for next revision.

>>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>>---
>> MAINTAINERS | 6 +
>> drivers/pci/hotplug/Kconfig | 12 +
>> drivers/pci/hotplug/Makefile | 3 +
>> drivers/pci/hotplug/pnv_php.c | 866 ++++++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 887 insertions(+)
>> create mode 100644 drivers/pci/hotplug/pnv_php.c
>>
>>diff --git a/MAINTAINERS b/MAINTAINERS
>>index 9f6685f..10088f1 100644
>>--- a/MAINTAINERS
>>+++ b/MAINTAINERS
>>@@ -7931,6 +7931,12 @@ L: linux-pci@vger.kernel.org
>> S: Supported
>> F: Documentation/PCI/pci-error-recovery.txt
>>
>>+PCI HOTPLUG DRIVER FOR POWERNV PLATFORM
>>+M: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>+L: linux-pci@vger.kernel.org
>>+S: Supported
>>+F: drivers/pci/hotplug/pnv_php.c
>>+
>> PCI SUBSYSTEM
>> M: Bjorn Helgaas <bhelgaas@google.com>
>> L: linux-pci@vger.kernel.org
>>diff --git a/drivers/pci/hotplug/Kconfig b/drivers/pci/hotplug/Kconfig
>>index df8caec..167c8ce 100644
>>--- a/drivers/pci/hotplug/Kconfig
>>+++ b/drivers/pci/hotplug/Kconfig
>>@@ -113,6 +113,18 @@ config HOTPLUG_PCI_SHPC
>>
>> When in doubt, say N.
>>
>>+config HOTPLUG_PCI_POWERNV
>>+ tristate "PowerPC PowerNV PCI Hotplug driver"
>>+ depends on PPC_POWERNV && EEH
>>+ help
>>+ Say Y here if you run PowerPC PowerNV platform that supports
>>+ PCI Hotplug
>>+
>>+ To compile this driver as a module, choose M here: the
>>+ module will be called pnv-php.
>>+
>>+ When in doubt, say N.
>>+
>> config HOTPLUG_PCI_RPA
>> tristate "RPA PCI Hotplug driver"
>> depends on PPC_PSERIES && EEH
>>diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
>>index b616e75..e33cdda 100644
>>--- a/drivers/pci/hotplug/Makefile
>>+++ b/drivers/pci/hotplug/Makefile
>>@@ -14,6 +14,7 @@ obj-$(CONFIG_HOTPLUG_PCI_PCIE) += pciehp.o
>> obj-$(CONFIG_HOTPLUG_PCI_CPCI_ZT5550) += cpcihp_zt5550.o
>> obj-$(CONFIG_HOTPLUG_PCI_CPCI_GENERIC) += cpcihp_generic.o
>> obj-$(CONFIG_HOTPLUG_PCI_SHPC) += shpchp.o
>>+obj-$(CONFIG_HOTPLUG_PCI_POWERNV) += pnv-php.o
>> obj-$(CONFIG_HOTPLUG_PCI_RPA) += rpaphp.o
>> obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR) += rpadlpar_io.o
>> obj-$(CONFIG_HOTPLUG_PCI_SGI) += sgi_hotplug.o
>>@@ -50,6 +51,8 @@ ibmphp-objs := ibmphp_core.o \
>> acpiphp-objs := acpiphp_core.o \
>> acpiphp_glue.o
>>
>>+pnv-php-objs := pnv_php.o
>>+
>> rpaphp-objs := rpaphp_core.o \
>> rpaphp_pci.o \
>> rpaphp_slot.o
>>diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c
>>new file mode 100644
>>index 0000000..415e9b9
>>--- /dev/null
>>+++ b/drivers/pci/hotplug/pnv_php.c
>>@@ -0,0 +1,866 @@
>>+/*
>>+ * PCI Hotplug Driver for PowerPC PowerNV platform.
>>+ *
>>+ * Copyright Gavin Shan, IBM Corporation 2015.
>>+ *
>>+ * 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.
>>+ */
>>+
>>+#include <linux/pci.h>
>>+#include <linux/pci_hotplug.h>
>>+#include <linux/module.h>
>>+
>>+#include <asm/opal.h>
>>+#include <asm/pnv-pci.h>
>>+#include <asm/ppc-pci.h>
>>+
>>+#define DRIVER_VERSION "0.1"
>>+#define DRIVER_AUTHOR "Gavin Shan, IBM Corporation"
>>+#define DRIVER_DESC "PowerPC PowerNV PCI Hotplug Driver"
>>+
>>+struct pnv_php_slot {
>>+ struct hotplug_slot php_slot;
>>+ struct hotplug_slot_info php_slot_info;
>>+ uint64_t id;
>>+ char *name;
>>+ int slot_no;
>>+ struct kref kref;
>>+ int state;
>>+#define PNV_PHP_STATE_INIT 0
>
>INITIALIZED
>
>>+#define PNV_PHP_STATE_REGISTER 1
>
>REGISTERED
>
>
>>+#define PNV_PHP_STATE_POPULATED 2
>
>This one has "ed" already :)
>
>And usually definitions go before the variable which uses them.
>
>>+ struct device_node *dn;
>>+ struct pci_dev *pdev;
>>+ struct pci_bus *bus;
>>+ bool power_state_check;
>>+ int power_state_confirmed;
>>+#define PNV_PHP_POWER_CONFIRMED_INVALID 0
>>+#define PNV_PHP_POWER_CONFIRMED_SUCCESS 1
>>+#define PNV_PHP_POWER_CONFIRMED_FAIL 2
>>+ struct opal_msg *msg;
>>+ void *fdt;
>>+ void *dt;
>>+ struct of_changeset ocs;
>>+ struct work_struct work;
>>+ wait_queue_head_t queue;
>>+ struct pnv_php_slot *parent;
>>+ struct list_head children;
>>+ struct list_head link;
>>+};
>>+
>>+static LIST_HEAD(pnv_php_slot_list);
>>+static DEFINE_SPINLOCK(pnv_php_lock);
>>+
>>+static void pnv_php_register(struct device_node *dn);
>>+static void pnv_php_unregister_one(struct device_node *dn);
>>+static void pnv_php_unregister(struct device_node *dn);
>>+
>>+static inline struct pnv_php_slot *pnv_php_get_slot(struct pnv_php_slot *slot)
>>+{
>>+ if (slot) {
>>+ kref_get(&slot->kref);
>>+ return slot;
>>+ }
>>+
>>+ return NULL;
>>+}
>>+
>>+static void pnv_php_free_slot(struct kref *kref)
>>+{
>>+ struct pnv_php_slot *slot = container_of(kref,
>>+ struct pnv_php_slot,
>>+ kref);
>>+
>>+ WARN_ON(!list_empty(&slot->children));
>>+ kfree(slot->name);
>>+ kfree(slot);
>>+}
>>+
>>+static inline void pnv_php_put_slot(struct pnv_php_slot *slot)
>>+{
>>+ if (!slot)
>>+ return;
>>+
>>+ kref_put(&slot->kref, pnv_php_free_slot);
>>+}
>>+
>>+static struct pnv_php_slot *pnv_php_match(struct device_node *dn,
>>+ struct pnv_php_slot *slot)
>>+{
>>+ struct pnv_php_slot *target, *tmp;
>>+
>>+ if (slot->dn == dn)
>>+ return pnv_php_get_slot(slot);
>>+
>>+ list_for_each_entry(tmp, &slot->children, link) {
>>+ target = pnv_php_match(dn, tmp);
>>+ if (target)
>>+ return target;
>>+ }
>>+
>>+ return NULL;
>>+}
>>+
>>+static struct pnv_php_slot *pnv_php_find_slot(struct device_node *dn)
>>+{
>>+ struct pnv_php_slot *slot, *tmp;
>>+ unsigned long flags;
>>+
>>+ spin_lock_irqsave(&pnv_php_lock, flags);
>>+ list_for_each_entry(tmp, &pnv_php_slot_list, link) {
>>+ slot = pnv_php_match(dn, tmp);
>>+ if (slot) {
>>+ spin_unlock_irqrestore(&pnv_php_lock, flags);
>>+ return slot;
>>+ }
>>+ }
>>+ spin_unlock_irqrestore(&pnv_php_lock, flags);
>>+
>>+ return NULL;
>>+}
>>+
>>+/*
>>+ * Remove pdn for all children of the indicated device node.
>>+ * The function should remove pdn in a depth-first manner.
>>+ */
>>+static void pnv_php_rmv_pdns(struct device_node *dn)
>>+{
>>+ struct device_node *child;
>>+
>>+ for_each_child_of_node(dn, child) {
>>+ pnv_php_rmv_pdns(child);
>>+
>>+ pci_remove_device_node_info(child);
>>+ }
>>+}
>>+
>>+/*
>>+ * Remove all child nodes of the indicated device nodes. The
>>+ * function should remove device nodes in depth-first manner.
>>+ */
>>+static int pnv_php_rmv_device_nodes(struct device_node *parent)
>>+{
>>+ struct device_node *dn, *child;
>>+ int ret = 0;
>>+
>>+ for_each_child_of_node(parent, dn) {
>>+ ret = pnv_php_rmv_device_nodes(dn);
>>+ if (ret)
>>+ return ret;
>>+
>>+ child = of_get_next_child(dn, NULL);
>>+ if (child) {
>>+ of_node_put(child);
>>+ of_node_put(dn);
>>+ pr_err("%s: Alive children of node <%s>\n",
>>+ __func__, of_node_full_name(dn));
>>+ return -EBUSY;
>>+ }
>>+
>>+ of_detach_node(dn);
>>+ of_node_put(dn);
>>+ }
>
>
>This loop iterates just once, is this correct? If so, then a loop is not
>needed here...
>
>
>>+
>>+ return 0;
>>+}
>>+
>>+/*
>>+ * The function processes the message sent by firmware
>>+ * to remove all device tree nodes beneath the slot's
>>+ * nodes and the associated auxiliary data.
>>+ */
>>+static void pnv_php_handle_poweroff(struct pnv_php_slot *slot)
>>+{
>>+ int ret;
>>+
>>+ pnv_php_rmv_pdns(slot->dn);
>>+
>>+ /*
>>+ * If the device sub-tree was created from OF changeset, simply
>>+ * to revert that. Otherwise, the device nodes in the sub-tree
>>+ * need to be iterated and detached.
>>+ */
>>+ if (slot->fdt) {
>>+ of_changeset_destroy(&slot->ocs);
>>+ kfree(slot->dt);
>>+ kfree(slot->fdt);
>>+ slot->dt = NULL;
>>+ slot->dn->child = NULL;
>>+ slot->fdt = NULL;
>>+ slot->power_state_confirmed = PNV_PHP_POWER_CONFIRMED_SUCCESS;
>>+ goto confirm;
>>+ }
>
>} else {
>
>>+
>>+ ret = pnv_php_rmv_device_nodes(slot->dn);
>>+ if (!ret) {
>>+ slot->power_state_confirmed = PNV_PHP_POWER_CONFIRMED_SUCCESS;
>>+ } else {
>>+ slot->power_state_confirmed = PNV_PHP_POWER_CONFIRMED_FAIL;
>>+ dev_warn(&slot->pdev->dev, "Error %d freeing nodes\n",
>>+ ret);
>
>Could be one line :)
>
>
>>+ }
>>+
>
>}
>and remove the label below?
>
>
>>+confirm:
>
>
>>+ wake_up_interruptible(&slot->queue);
>>+}
>>+
>>+static int pnv_php_populate_changeset(struct of_changeset *ocs,
>>+ struct device_node *dn)
>>+{
>>+ struct device_node *child;
>>+ int ret = 0;
>>+
>>+ for_each_child_of_node(dn, child) {
>>+ ret = of_changeset_attach_node(ocs, child);
>>+ if (ret)
>>+ return ret;
>>+
>>+ ret = pnv_php_populate_changeset(ocs, child);
>
>if (ret) break; may be?
>
>
>>+ }
>>+
>>+ return ret;
>>+}
>>+
>>+static void *pnv_php_add_one_pdn(struct device_node *dn, void *data)
>>+{
>>+ struct pci_controller *hose = (struct pci_controller *)data;
>>+ struct pci_dn *pdn;
>>+
>>+ pdn = pci_add_device_node_info(hose, dn);
>>+ if (!pdn)
>>+ return ERR_PTR(-ENOMEM);
>>+
>>+ return NULL;
>>+}
>>+
>>+static void pnv_php_add_pdns(struct pnv_php_slot *slot)
>>+{
>>+ struct pci_controller *hose = pci_bus_to_host(slot->bus);
>>+
>>+ pci_traverse_device_nodes(slot->dn, pnv_php_add_one_pdn, hose);
>>+}
>>+
>>+static void pnv_php_handle_poweron(struct pnv_php_slot *slot)
>>+{
>>+ void *fdt, *dt;
>>+ uint64_t len;
>>+ int confirm = PNV_PHP_POWER_CONFIRMED_SUCCESS;
>>+ int ret;
>>+
>>+ /* We don't know the FDT blob size. It tries with incremental
>>+ * sized memory chunk.
>>+ */
>>+ for (len = 0x2000; len <= 0x10000; len += 0x2000) {
>>+ fdt = kzalloc(len, GFP_KERNEL);
>>+ if (!fdt)
>>+ break;
>>+
>>+ ret = pnv_pci_get_device_tree(slot->dn->phandle, fdt, len);
>>+ if (!ret)
>>+ break;
>>+
>>+ kfree(fdt);
>>+ }
>>+
>>+ if (len > 0x10000) {
>>+ dev_warn(&slot->pdev->dev, "Cannot alloc FDT blob\n");
>>+ goto out;
>
>This seems like an error but slot->power_state_confirmed will be set to
>PNV_PHP_POWER_CONFIRMED_SUCCESS anyway, is that correct?
>
>
>>+ }
>
>I'd redo the chunk above like this:
>
>fdt1 = kzalloc(0x10000);
>if (!fdt1)
> goto out;
>ret = pnv_pci_get_device_tree(slot->dn->phandle, fdt1, 0x10000);
>if (!ret)
> goto out;
>fdt = kzalloc(fdt_totalsize(fdt1));
>if (!fdt)
> goto out;
>memcpy(fdt, fdt1, fdt_totalsize(fdt1));
>kfree(fdt1);
>
>
>This way you end up using less memory after setup has completed.
>
>And what is an usual size of the returned blob?
>
>
>>+
>>+ /* Unflatten device tree blob */
>>+ dt = of_fdt_unflatten_tree(fdt, slot->dn, NULL);
>>+ if (!dt) {
>>+ dev_warn(&slot->pdev->dev, "Cannot unflatten FDT\n");
>>+ goto free_fdt;
>>+ }
>>+
>>+ /* Initialize and apply the changeset */
>>+ of_changeset_init(&slot->ocs);
>>+ ret = pnv_php_populate_changeset(&slot->ocs, slot->dn);
>>+ if (ret) {
>>+ dev_warn(&slot->pdev->dev, "Error %d populating changeset\n",
>>+ ret);
>>+ goto free_dt;
>>+ }
>>+
>>+ slot->dn->child = NULL;
>>+ ret = of_changeset_apply(&slot->ocs);
>>+ if (ret) {
>>+ dev_warn(&slot->pdev->dev, "Error %d applying changeset\n",
>>+ ret);
>>+ goto destroy_changeset;
>>+ }
>>+
>>+ /* Add device node firmware data */
>>+ pnv_php_add_pdns(slot);
>>+ slot->fdt = fdt;
>>+ slot->dt = dt;
>>+ goto out;
>>+
>>+destroy_changeset:
>>+ of_changeset_destroy(&slot->ocs);
>>+free_dt:
>>+ kfree(dt);
>>+ slot->dn->child = NULL;
>>+free_fdt:
>>+ kfree(fdt);
>>+ confirm = PNV_PHP_POWER_CONFIRMED_FAIL;
>>+out:
>>+ /* Confirm status change */
>>+ slot->power_state_confirmed = confirm;
>>+ wake_up_interruptible(&slot->queue);
>>+}
>>+
>>+static void pnv_php_work(struct work_struct *data)
>>+{
>>+ struct pnv_php_slot *slot = container_of(data,
>>+ struct pnv_php_slot, work);
>>+ uint64_t event = be64_to_cpu(slot->msg->params[0]);
>>+
>>+ if (event == OPAL_PCI_SLOT_POWER_OFF)
>>+ pnv_php_handle_poweroff(slot);
>>+ else
>>+ pnv_php_handle_poweron(slot);
>>+
>>+ pnv_php_put_slot(slot);
>>+}
>>+
>>+static int pnv_php_handle_msg(struct notifier_block *nb,
>>+ unsigned long type,
>>+ void *message)
>>+{
>>+ phandle h;
>>+ struct device_node *dn;
>>+ struct pnv_php_slot *slot;
>>+ struct opal_msg *msg = message;
>>+
>>+ if (type != OPAL_MSG_PCI_HOTPLUG) {
>>+ pr_warn("%s: Invalid message %ld received!\n",
>>+ __func__, type);
>>+ return NOTIFY_DONE;
>>+ }
>>+
>>+ h = (phandle)be64_to_cpu(msg->params[1]);
>>+ dn = of_find_node_by_phandle(h);
>>+ if (!dn) {
>>+ pr_warn("%s: No device node for phandle 0x%x\n",
>>+ __func__, h);
>>+ return NOTIFY_DONE;
>>+ }
>>+
>>+ slot = pnv_php_find_slot(dn);
>>+ of_node_put(dn);
>>+ if (!slot) {
>>+ pr_warn("%s: No slot found for node <%s>\n",
>>+ __func__, of_node_full_name(dn));
>>+ of_node_put(dn);
>
>You already put the node 5 lines above, is this correct?
>
>>+ return NOTIFY_DONE;
>>+ }
>>+
>>+ slot->msg = msg;
>>+ schedule_work(&slot->work);
>>+ return NOTIFY_OK;
>>+}
>>+
>>+static int pnv_php_set_power_state(struct hotplug_slot *php_slot, u8 state)
>>+{
>>+ struct pnv_php_slot *slot = php_slot->private;
>
>
>Most instances of "struct pnv_php_slot" are called "slot".
>Most instances of "struct hotplug_slot" are called "php_slot".
>
>When I read this code, I have to remind myself that a "php_slot" variable
>(which has "php" in it) is NOT of the type with "php" (i.e. NOT
>"pnv_php_slot").
>
>I would suggest swapping slot <-> php_slot.
>
>
>>+ int ret;
>>+
>>+ slot->power_state_confirmed = PNV_PHP_POWER_CONFIRMED_INVALID;
>>+ ret = pnv_pci_set_power_state(slot->id, state);
>>+ if (ret) {
>>+ dev_warn(&slot->pdev->dev, "Error %d powering %s slot\n",
>>+ ret, state ? "on" : "off");
>>+ return ret;
>>+ }
>>+
>>+ /* Continue to PCI probing after finalized device-tree. The
>>+ * device-tree might have been updated completely at this
>>+ * point. Thus we don't have to always waiting for that.
>
>s/always waiting/wait forever/ ?
>
>>+ */
>>+ if (slot->power_state_confirmed == PNV_PHP_POWER_CONFIRMED_SUCCESS)
>>+ return 0;
>>+ else if (slot->power_state_confirmed == PNV_PHP_POWER_CONFIRMED_FAIL)
>
>
>No need in "else" here.
>
>
>>+ return -EBUSY;
>>+
>>+ ret = wait_event_timeout(slot->queue,
>>+ slot->power_state_confirmed, 10 * HZ);
>
>The code flow is unclear in this case.
>
>The queue is signaled from pnv_php_handle_poweron() which is "work" and
>scheduled by pnv_php_handle_msg() and it is not obvious what code calls
>pnv_php_handle_msg().
>
>
>
>>+ if (!ret) {
>>+ dev_warn(&slot->pdev->dev, "Error %d waiting for power-%s\n",
>>+ ret, state ? "on" : "off");
>>+ return -EBUSY;
>>+ }
>>+
>>+ if (slot->power_state_confirmed == PNV_PHP_POWER_CONFIRMED_SUCCESS)
>>+ return 0;
>>+
>>+ dev_warn(&slot->pdev->dev, "Error status %d for power-%s\n",
>>+ slot->power_state_confirmed, state ? "on" : "off");
>>+ return -EBUSY;
>>+}
>>+
>>+static int pnv_php_get_power_state(struct hotplug_slot *php_slot, u8 *state)
>>+{
>>+ struct pnv_php_slot *slot = php_slot->private;
>>+ uint8_t power_state;
>>+ int ret;
>>+
>>+ /*
>>+ * Retrieve power status from firmware. If we fail
>>+ * getting that, the power status fails back to
>>+ * be on.
>>+ */
>>+ ret = pnv_pci_get_power_state(slot->id, &power_state);
>>+ if (ret) {
>>+ *state = OPAL_PCI_SLOT_POWER_ON;
>>+ dev_warn(&slot->pdev->dev, "Error %d getting power status\n",
>>+ ret);
>>+ } else {
>>+ *state = power_state;
>>+ php_slot->info->power_status = power_state;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+static int pnv_php_get_adapter_state(struct hotplug_slot *php_slot, u8 *state)
>>+{
>>+ struct pnv_php_slot *slot = php_slot->private;
>>+ uint8_t presence;
>>+ int ret;
>>+
>>+ /*
>>+ * Retrieve presence status from firmware. If we can't
>>+ * get that, it will fail back to be empty.
>>+ */
>>+ ret = pnv_pci_get_presence_state(slot->id, &presence);
>>+ if (ret >= 0) {
>>+ *state = presence;
>>+ php_slot->info->adapter_status = presence;
>>+ ret = 0;
>>+ } else {
>>+ *state = OPAL_PCI_SLOT_EMPTY;
>>+ dev_warn(&slot->pdev->dev, "Error %d getting presence\n",
>>+ ret);
>>+ }
>>+
>>+ return ret;
>>+}
>>+
>>+static int pnv_php_set_attention_state(struct hotplug_slot *php_slot, u8 state)
>>+{
>>+ /* FIXME: Make it real once firmware supports it */
>>+ php_slot->info->attention_status = state;
>>+
>>+ return 0;
>>+}
>>+
>>+static int pnv_php_enable(struct pnv_php_slot *slot, bool rescan)
>>+{
>>+ struct hotplug_slot *php_slot = &slot->php_slot;
>>+ uint8_t presence, power_status;
>>+ int ret;
>>+
>>+ /* Check if the slot has been configured */
>>+ if (slot->state != PNV_PHP_STATE_REGISTER)
>>+ return 0;
>>+
>>+ /* Retrieve slot presence status */
>>+ ret = php_slot->ops->get_adapter_status(php_slot, &presence);
>
>
>Here and in other places there is no point in dereferencing ops, just call
>pnv_php_get_adapter_state() here directly as you decided not to have a
>separate source file for pnv_php_slot.
>
>
>>+ if (ret)
>>+ return ret;
>>+
>>+ /* Proceed if there have nothing behind the slot */
>>+ if (presence == OPAL_PCI_SLOT_EMPTY)
>>+ goto scan;
>>+
>>+ /*
>>+ * If we don't detect something behind the slot, we need
>>+ * make sure the power suply to the slot is on.
>
>Is this correct - "don't detect" -> "make sure it is on"?
>
>
>>Otherwise,
>>+ * the slot downstream PCIe linkturn should be down.
>>+ *
>>+ * On the first time, we don't change the power status to
>>+ * boost system boot with assumption that the firmware
>
>Out of curiosity - does it really boost booting? :)
>
>
>>+ * supplies consistent slot power status: empty slot always
>>+ * has its power off and non-empty slot has its power on.
>>+ */
>>+ if (!slot->power_state_check) {
>>+ slot->power_state_check = true;
>>+ goto scan;
>>+ }
>>+
>>+ /* Check the power status. Scan the slot if that's already on */
>>+ ret = php_slot->ops->get_power_status(php_slot, &power_status);
>>+ if (ret)
>>+ return ret;
>>+
>>+ if (power_status == OPAL_PCI_SLOT_POWER_ON)
>>+ goto scan;
>>+
>>+ /* Power is off, turn it on and then scan the slot */
>>+ ret = pnv_php_set_power_state(php_slot, OPAL_PCI_SLOT_POWER_ON);
>>+ if (ret)
>>+ return ret;
>>+
>>+scan:
>>+ if (presence == OPAL_PCI_SLOT_PRESENT) {
>>+ if (rescan) {
>>+ pci_lock_rescan_remove();
>>+ pci_add_pci_devices(slot->bus);
>>+ pci_unlock_rescan_remove();
>>+ }
>>+
>>+ /* Rescan for child hotpluggable slots */
>>+ slot->state = PNV_PHP_STATE_POPULATED;
>>+ if (rescan)
>>+ pnv_php_register(slot->dn);
>
>
>The chunk above adds a parent slot (a physical slot) and then scans for
>children slots (a mighty extended with extra physical slots)? :)
>
>
>>+ } else {
>>+ slot->state = PNV_PHP_STATE_POPULATED;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+static int pnv_php_enable_slot(struct hotplug_slot *php_slot)
>>+{
>>+ struct pnv_php_slot *slot = container_of(php_slot,
>>+ struct pnv_php_slot,
>>+ php_slot);
>>+
>>+ return pnv_php_enable(slot, true);
>>+}
>>+
>>+static int pnv_php_disable_slot(struct hotplug_slot *php_slot)
>>+{
>>+ struct pnv_php_slot *slot = php_slot->private;
>>+ uint8_t power_state;
>>+ int ret;
>>+
>>+ if (slot->state != PNV_PHP_STATE_POPULATED)
>>+ return 0;
>>+
>>+ /* Remove all devices behind the slot */
>>+ pci_lock_rescan_remove();
>>+ pci_remove_pci_devices(slot->bus);
>>+ pci_unlock_rescan_remove();
>>+
>>+ /* Detach the child hotpluggable slots */
>>+ pnv_php_unregister(slot->dn);
>>+
>>+ /*
>>+ * Check the power status and turn it off if necessary. If we
>>+ * fail to get the power status, the power will be forced to
>>+ * be off.
>>+ */
>>+ ret = php_slot->ops->get_power_status(php_slot, &power_state);
>>+ if (ret || power_state == OPAL_PCI_SLOT_POWER_ON) {
>>+ ret = pnv_php_set_power_state(php_slot,
>>+ OPAL_PCI_SLOT_POWER_OFF);
>>+ if (ret)
>>+ dev_warn(&slot->pdev->dev, "Error %d powering off\n",
>>+ ret);
>>+ }
>>+
>>+ /* Update slot state */
>>+ slot->state = PNV_PHP_STATE_REGISTER;
>>+ return 0;
>>+}
>>+
>>+static struct hotplug_slot_ops php_slot_ops = {
>>+ .get_power_status = pnv_php_get_power_state,
>>+ .get_adapter_status = pnv_php_get_adapter_state,
>>+ .set_attention_status = pnv_php_set_attention_state,
>>+ .enable_slot = pnv_php_enable_slot,
>>+ .disable_slot = pnv_php_disable_slot,
>>+};
>>+
>>+static void pnv_php_release(struct hotplug_slot *hp_slot)
>>+{
>>+ struct pnv_php_slot *slot = hp_slot->private;
>>+ unsigned long flags;
>>+
>>+ /* Remove from global or child list */
>>+ spin_lock_irqsave(&pnv_php_lock, flags);
>>+ list_del(&slot->link);
>>+ spin_unlock_irqrestore(&pnv_php_lock, flags);
>>+
>>+ /* Detach from parent */
>>+ pnv_php_put_slot(slot);
>>+ pnv_php_put_slot(slot->parent);
>>+}
>>+
>>+static int pnv_php_get_slot_id(struct device_node *dn, uint64_t *id)
>>+{
>>+ struct device_node *parent = dn;
>>+ const __be64 *prop64;
>>+ const __be32 *prop32;
>>+
>>+ /*
>>+ * The hotpluggable slot always has a compound Id, which
>>+ * consists of 16-bits PHB Id, 16 bits bus/slot/function
>>+ * number, and compound indicator
>>+ */
>>+ *id = (0x1ul << 63);
>>+
>>+ /* Bus/Slot/Function number */
>>+ prop32 = of_get_property(dn, "reg", NULL);
>>+ if (!prop32)
>>+ return -ENXIO;
>>+ *id |= ((of_read_number(prop32, 1) & 0x00ffff00) << 8);
>>+
>>+ /* PHB Id */
>>+ while ((parent = of_get_parent(parent))) {
>>+ if (!PCI_DN(parent)) {
>>+ of_node_put(parent);
>>+ break;
>>+ }
>>+
>>+ if (!of_device_is_compatible(parent, "ibm,ioda2-phb") &&
>>+ !of_device_is_compatible(parent, "ibm,ioda-phb")) {
>>+ of_node_put(parent);
>>+ continue;
>>+ }
>>+
>>+ prop64 = of_get_property(parent, "ibm,opal-phbid", NULL);
>>+ if (!prop64) {
>>+ of_node_put(parent);
>>+ return -ENXIO;
>>+ }
>>+
>>+ *id |= be64_to_cpup(prop64);
>>+ of_node_put(parent);
>>+ return 0;
>>+ }
>>+
>>+ return -ENODEV;
>>+}
>>+
>>+static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn)
>>+{
>>+ struct pnv_php_slot *slot;
>>+ struct pci_bus *bus;
>>+ const char *label;
>>+ uint64_t id;
>>+
>>+ label = of_get_property(dn, "ibm,slot-label", NULL);
>>+ if (!label)
>>+ return NULL;
>>+
>>+ if (pnv_php_get_slot_id(dn, &id))
>>+ return NULL;
>>+
>>+ bus = pci_find_bus_by_node(dn);
>>+ if (!bus)
>>+ return NULL;
>>+
>>+ slot = kzalloc(sizeof(*slot), GFP_KERNEL);
>>+ if (!slot)
>>+ return NULL;
>>+
>>+ slot->name = kstrdup(label, GFP_KERNEL);
>>+ if (!slot->name) {
>>+ kfree(slot);
>>+ return NULL;
>>+ }
>>+
>>+ if (dn->child && PCI_DN(dn->child))
>>+ slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn);
>>+ else
>>+ slot->slot_no = -1; /* Placeholder slot */
>>+
>>+ kref_init(&slot->kref);
>>+ slot->state = PNV_PHP_STATE_INIT;
>>+ slot->dn = dn;
>>+ slot->pdev = bus->self;
>>+ slot->bus = bus;
>>+ slot->id = id;
>>+ slot->power_state_check = false;
>>+ slot->power_state_confirmed = PNV_PHP_POWER_CONFIRMED_INVALID;
>>+ slot->php_slot.ops = &php_slot_ops;
>>+ slot->php_slot.info = &slot->php_slot_info;
>>+ slot->php_slot.release = pnv_php_release;
>>+ slot->php_slot.private = slot;
>>+
>>+ INIT_WORK(&slot->work, pnv_php_work);
>>+ init_waitqueue_head(&slot->queue);
>>+ INIT_LIST_HEAD(&slot->children);
>>+ INIT_LIST_HEAD(&slot->link);
>>+
>>+ return slot;
>>+}
>>+
>>+static int pnv_php_register_slot(struct pnv_php_slot *slot)
>>+{
>>+ struct pnv_php_slot *parent;
>>+ struct device_node *dn = slot->dn;
>>+ unsigned long flags;
>>+ int ret;
>>+
>>+ /* Check if the slot exists or not */
>
>s/exists/is registered/
>
>
>>+ parent = pnv_php_find_slot(slot->dn);
>>+ if (parent) {
>>+ pnv_php_put_slot(parent);
>>+ return -EEXIST;
>>+ }
>>+
>>+ /* Register PCI slot */
>>+ ret = pci_hp_register(&slot->php_slot, slot->bus,
>>+ slot->slot_no, slot->name);
>>+ if (ret) {
>>+ dev_warn(&slot->pdev->dev, "Error %d registering slot\n",
>>+ ret);
>>+ return ret;
>>+ }
>>+
>>+ /* Attach to the parent's child list or global list */
>>+ while ((dn = of_get_parent(dn))) {
>>+ if (!PCI_DN(dn)) {
>>+ of_node_put(dn);
>>+ break;
>>+ }
>>+
>>+ parent = pnv_php_find_slot(dn);
>>+ if (parent) {
>>+ of_node_put(dn);
>>+ break;
>>+ }
>
>This is missing here:
>
>of_node_put(dn);
>
>
>>+ }
>>+
>>+ spin_lock_irqsave(&pnv_php_lock, flags);
>>+ slot->parent = parent;
>>+ if (parent)
>>+ list_add_tail(&slot->link, &parent->children);
>>+ else
>>+ list_add_tail(&slot->link, &pnv_php_slot_list);
>>+ spin_unlock_irqrestore(&pnv_php_lock, flags);
>>+
>>+ slot->state = PNV_PHP_STATE_REGISTER;
>>+ return 0;
>>+}
>>+
>>+static int pnv_php_register_one(struct device_node *dn)
>>+{
>>+ struct pnv_php_slot *slot;
>>+ const __be32 *prop32;
>>+ int ret;
>>+
>>+ /* Check if it's hotpluggable slot */
>>+ prop32 = of_get_property(dn, "ibm,slot-pluggable", NULL);
>>+ if (!prop32 || !of_read_number(prop32, 1))
>>+ return -ENXIO;
>>+
>>+ prop32 = of_get_property(dn, "ibm,reset-by-firmware", NULL);
>>+ if (!prop32 || !of_read_number(prop32, 1))
>>+ return -ENXIO;
>>+
>>+ slot = pnv_php_alloc_slot(dn);
>>+ if (!slot)
>>+ return -ENODEV;
>>+
>>+ ret = pnv_php_register_slot(slot);
>>+ if (ret)
>>+ goto free_slot;
>>+
>>+ ret = pnv_php_enable(slot, false);
>>+ if (ret)
>>+ goto unregister_slot;
>>+
>>+ return 0;
>>+
>>+unregister_slot:
>>+ pnv_php_unregister_one(slot->dn);
>>+free_slot:
>>+ pnv_php_put_slot(slot);
>>+ return ret;
>>+}
>>+
>>+static void pnv_php_register(struct device_node *dn)
>>+{
>>+ struct device_node *child;
>>+
>>+ /*
>>+ * The parent slots should be registered before their
>>+ * child slots.
>>+ */
>>+ for_each_child_of_node(dn, child) {
>>+ pnv_php_register_one(child);
>>+ pnv_php_register(child);
>>+ }
>>+}
>>+
>>+static void pnv_php_unregister_one(struct device_node *dn)
>>+{
>>+ struct pnv_php_slot *slot;
>>+
>>+ slot = pnv_php_find_slot(dn);
>>+ if (!slot)
>>+ return;
>>+
>>+ pnv_php_put_slot(slot);
>>+ pci_hp_deregister(&slot->php_slot);
>>+}
>>+
>>+static void pnv_php_unregister(struct device_node *dn)
>>+{
>>+ struct device_node *child;
>>+
>>+ /* The child slots should go before their parent slots */
>>+ for_each_child_of_node(dn, child) {
>>+ pnv_php_unregister(child);
>>+ pnv_php_unregister_one(child);
>>+ }
>>+}
>>+
>>+static struct notifier_block php_msg_nb = {
>>+ .notifier_call = pnv_php_handle_msg,
>>+ .next = NULL,
>>+ .priority = 0,
>>+};
>>+
>>+static int __init pnv_php_init(void)
>>+{
>>+ struct device_node *dn;
>>+ int ret;
>>+
>>+ pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
>>+
>>+ /* Register hotplug message handler */
>>+ ret = pnv_pci_hotplug_notifier_register(&php_msg_nb);
>>+ if (ret) {
>>+ pr_warn("%s: Error %d registering hotplug notifier\n",
>>+ __func__, ret);
>>+ return ret;
>>+ }
>>+
>>+ /* Scan PHB nodes and their children */
>>+ for_each_compatible_node(dn, NULL, "ibm,ioda-phb")
>>+ pnv_php_register(dn);
>>+ for_each_compatible_node(dn, NULL, "ibm,ioda2-phb")
>>+ pnv_php_register(dn);
>>+
>>+ return 0;
>>+}
>>+
>>+static void __exit pnv_php_exit(void)
>>+{
>>+ struct device_node *dn;
>>+
>>+ for_each_compatible_node(dn, NULL, "ibm,ioda-phb")
>>+ pnv_php_unregister(dn);
>>+ for_each_compatible_node(dn, NULL, "ibm,ioda2-phb")
>>+ pnv_php_unregister(dn);
>>+
>>+ pnv_pci_hotplug_notifier_unregister(&php_msg_nb);
>>+}
>>+
>>+module_init(pnv_php_init);
>>+module_exit(pnv_php_exit);
>>+
>>+MODULE_VERSION(DRIVER_VERSION);
>>+MODULE_LICENSE("GPL v2");
>>+MODULE_AUTHOR(DRIVER_AUTHOR);
>>+MODULE_DESCRIPTION(DRIVER_DESC);
>>
>
>
>--
>Alexey
>