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[PATCH V8 0/8] Introduce ACPI world to ITS irqchip

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  [PATCH V8 0/8] Introduce ACPI world to ITS irqchip Tomasz Nowicki <tn@semihalf.com> - 2016-08-11 12:10 +0200
    [PATCH V8 3/8] PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table Tomasz Nowicki <tn@semihalf.com> - 2016-08-11 12:10 +0200
    [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling Tomasz Nowicki <tn@semihalf.com> - 2016-08-11 12:10 +0200
      Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI  domain handling Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-08-12 18:50 +0200
        RE: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI  domain handling "Zheng, Lv" <lv.zheng@intel.com> - 2016-08-16 04:20 +0200
          Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain  handling Marc Zyngier <marc.zyngier@arm.com> - 2016-08-16 12:50 +0200

#1460362 — [PATCH V8 0/8] Introduce ACPI world to ITS irqchip

The series builds the PCI/MSI domain stack based on initial IORT driver
which is added in first place. As a reference please see IORT spec:
http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf

Tested on Cavium ThunderX server and Qualcomm Technologies server platform QDF2XXX.
The patches can be found here:
https://github.com/semihalf-nowicki-tomasz/linux.git (its-acpi-v8)

v7 -> v8
- rebased against v4.8-rc1
- move IORT support under new drivers/acpi/arm64 directory
- memory leak fix for iort_match_node_callback()
- iort_node_map_rid() algorithm improvements
- fix RID match check in iort_id_map()
- fix typos and white spaces

v6 -> v7
- rebased against irq/irqchip-4.8
- improvements for IORT ID mapping
- call IORT init call from acpi_init() instead of arch_initcall()
- split IORT driver in to two parts: core and ITS/MSI

v5 -> v6
- added locking mechanism for IORT list with domain token
- IORT function name improvements
- extended IORT RID mapping helper
- reworked IORT to be more SMMU friendly
- IORT functions which map RID and find corresponding domain are not
  PCI specific any more (struct pci_dev -> struct device)
- bug fixes

v4 -> v5
- rebased against v4.7-rc1
- drop generic layer and call IORT functions directly
- improve resource abstraction and string formatting

v3 -> v4
- rebased against v4.5
- add ACPI support for IRQ domain handling on a per-device basis
- reorder domain setup step
- improve error handling
- code style improvements

v2 -> v3
- rebased on top of 4.4
- fixes and improvements for redistributor init via GICC structures
- fixes as per kbuild reports

v1 -> v2
- rebased on top of 4.4-rc4
- use pci_msi_domain_get_msi_rid for requester ID to device ID translation

Tomasz Nowicki (8):
  ACPI: I/O Remapping Table (IORT) initial support
  ACPI: Add new IORT functions to support MSI domain handling
  PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table
  irqchip/gicv3-its: Cleanup for ITS domain initialization
  irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI
  irqchip/gicv3-its: Probe ITS in the ACPI way
  irqchip/gicv3-its: Factor out PCI-MSI part that might be reused for
    ACPI
  irqchip/gicv3-its: Use MADT ITS subtable to do PCI/MSI domain
    initialization

 drivers/acpi/Kconfig                     |   5 +
 drivers/acpi/Makefile                    |   2 +
 drivers/acpi/arm64/Kconfig               |   6 +
 drivers/acpi/arm64/Makefile              |   1 +
 drivers/acpi/arm64/iort.c                | 387 +++++++++++++++++++++++++++++++
 drivers/acpi/bus.c                       |   2 +
 drivers/irqchip/Kconfig                  |   1 +
 drivers/irqchip/irq-gic-v3-its-pci-msi.c |  88 +++++--
 drivers/irqchip/irq-gic-v3-its.c         | 169 ++++++++++----
 drivers/irqchip/irq-gic-v3.c             |   7 +-
 drivers/pci/msi.c                        |  11 +-
 include/linux/iort.h                     |  41 ++++
 include/linux/irqchip/arm-gic-v3.h       |   4 +-
 13 files changed, 654 insertions(+), 70 deletions(-)
 create mode 100644 drivers/acpi/arm64/Kconfig
 create mode 100644 drivers/acpi/arm64/Makefile
 create mode 100644 drivers/acpi/arm64/iort.c
 create mode 100644 include/linux/iort.h

-- 
1.9.1

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#1460365 — [PATCH V8 3/8] PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table

It is possible to provide information about which MSI controller to
use on a per-device basis for DT. This patch supply this with ACPI support.

Currently, IORT is the only one ACPI table which can provide such mapping.
In order to plug IORT into MSI infrastructure we are adding ACPI
equivalents for finding PCI device domain and its RID translation
(pci_msi_domain_get_msi_rid and pci_msi_domain_get_msi_rid calls).

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/msi.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index a02981e..7bb981a 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -19,6 +19,7 @@
 #include <linux/smp.h>
 #include <linux/errno.h>
 #include <linux/io.h>
+#include <linux/iort.h>
 #include <linux/slab.h>
 #include <linux/irqdomain.h>
 #include <linux/of_irq.h>
@@ -1498,8 +1499,8 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
 
 	of_node = irq_domain_get_of_node(domain);
-	if (of_node)
-		rid = of_msi_map_rid(&pdev->dev, of_node, rid);
+	rid = of_node ? of_msi_map_rid(&pdev->dev, of_node, rid) :
+			iort_msi_map_rid(&pdev->dev, rid);
 
 	return rid;
 }
@@ -1515,9 +1516,13 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
  */
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
 {
+	struct irq_domain *dom;
 	u32 rid = 0;
 
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
-	return of_msi_map_get_device_domain(&pdev->dev, rid);
+	dom = of_msi_map_get_device_domain(&pdev->dev, rid);
+	if (!dom)
+		dom = iort_get_device_domain(&pdev->dev, rid);
+	return dom;
 }
 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
-- 
1.9.1

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#1460366 — [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling

For ITS, MSI functionality consists on building domain stack and
during that process we need to reference to domain stack components
e.g. before we create new DOMAIN_BUS_PCI_MSI domain we need to specify
its DOMAIN_BUS_NEXUS parent domain. In order to manage that process
properly, maintain list which elements contain domain token
(unique for MSI domain stack) and ITS ID: iort_register_domain_token()
and iort_deregister_domain_token(). Then retrieve domain token
any time later with ITS ID being key off: iort_find_domain_token().
With domain token and domain type we are able to find corresponding
IRQ domain.

Since IORT is prepared to describe MSI domain on a per-device basis,
use existing IORT helpers and implement two calls:
1. iort_msi_map_rid() to map MSI RID for a device
2. iort_get_device_domain() to find domain token for a device

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 drivers/acpi/arm64/iort.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/iort.h      |  11 +++
 2 files changed, 180 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index f89056e..a03386d 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -22,12 +22,91 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 
+struct iort_its_msi_chip {
+	struct list_head	list;
+	struct fwnode_handle	*fw_node;
+	u32			translation_id;
+};
+
 typedef acpi_status (*iort_find_node_callback)
 	(struct acpi_iort_node *node, void *context);
 
 /* Root pointer to the mapped IORT table */
 static struct acpi_table_header *iort_table;
 
+static LIST_HEAD(iort_msi_chip_list);
+static DEFINE_SPINLOCK(iort_msi_chip_lock);
+
+/**
+ * iort_register_domain_token() - register domain token and related ITS ID
+ * to the list from where we can get it back later on.
+ * @trans_id: ITS ID.
+ * @fw_node: Domain token.
+ *
+ * Returns: 0 on success, -ENOMEM if no memory when allocating list element
+ */
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
+{
+	struct iort_its_msi_chip *its_msi_chip;
+
+	its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
+	if (!its_msi_chip)
+		return -ENOMEM;
+
+	its_msi_chip->fw_node = fw_node;
+	its_msi_chip->translation_id = trans_id;
+
+	spin_lock(&iort_msi_chip_lock);
+	list_add(&its_msi_chip->list, &iort_msi_chip_list);
+	spin_unlock(&iort_msi_chip_lock);
+
+	return 0;
+}
+
+/**
+ * iort_deregister_domain_token() - Deregister domain token based on ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: none.
+ */
+void iort_deregister_domain_token(int trans_id)
+{
+	struct iort_its_msi_chip *its_msi_chip, *t;
+
+	spin_lock(&iort_msi_chip_lock);
+	list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
+		if (its_msi_chip->translation_id == trans_id) {
+			list_del(&its_msi_chip->list);
+			kfree(its_msi_chip);
+			break;
+		}
+	}
+	spin_unlock(&iort_msi_chip_lock);
+}
+
+/**
+ * iort_find_domain_token() - Find domain token based on given ITS ID
+ * @trans_id: ITS ID.
+ *
+ * Returns: domain token when find on the list, NULL otherwise
+ */
+struct fwnode_handle *iort_find_domain_token(int trans_id)
+{
+	struct fwnode_handle *fw_node = NULL;
+	struct iort_its_msi_chip *its_msi_chip;
+
+	spin_lock(&iort_msi_chip_lock);
+	list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
+		if (its_msi_chip->translation_id == trans_id) {
+			fw_node = its_msi_chip->fw_node;
+			break;
+		}
+	}
+	spin_unlock(&iort_msi_chip_lock);
+
+	return fw_node;
+}
+
 static struct acpi_iort_node *
 iort_scan_node(enum acpi_iort_node_type type,
 	       iort_find_node_callback callback, void *context)
@@ -206,6 +285,96 @@ iort_find_dev_node(struct device *dev)
 			      iort_match_node_callback, &pbus->dev);
 }
 
+/**
+ * iort_msi_map_rid() - Map a MSI requester ID for a device
+ * @dev: The device for which the mapping is to be done.
+ * @req_id: The device requester ID.
+ *
+ * Returns: mapped MSI RID on success, input requester ID otherwise
+ */
+u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{
+	struct acpi_iort_node *node;
+	u32 dev_id;
+
+	if (!iort_table)
+		return req_id;
+
+	node = iort_find_dev_node(dev);
+	if (!node) {
+		dev_err(dev, "can't find related IORT node\n");
+		return req_id;
+	}
+
+	iort_node_map_rid(node, req_id, &dev_id, ACPI_IORT_NODE_ITS_GROUP);
+	return dev_id;
+}
+
+/**
+ * iort_dev_find_its_id() - Find the ITS identifier for a device
+ * @dev: The device.
+ * @idx: Index of the ITS identifier list.
+ * @its_id: ITS identifier.
+ *
+ * Returns: 0 on success, appropriate error value otherwise
+ */
+static int
+iort_dev_find_its_id(struct device *dev, u32 req_id, unsigned int idx,
+		     int *its_id)
+{
+	struct acpi_iort_its_group *its;
+	struct acpi_iort_node *node;
+
+	node = iort_find_dev_node(dev);
+	if (!node) {
+		dev_err(dev, "can't find related IORT node\n");
+		return -ENXIO;
+	}
+
+	node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP);
+	if (!node) {
+		dev_err(dev, "can't find related ITS node\n");
+		return -ENXIO;
+	}
+
+	/* Move to ITS specific data */
+	its = (struct acpi_iort_its_group *)node->node_data;
+	if (idx > its->its_count) {
+		dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n",
+			idx, its->its_count);
+		return -ENXIO;
+	}
+
+	*its_id = its->identifiers[idx];
+	return 0;
+}
+
+/**
+ * iort_get_device_domain() - Find MSI domain related to a device
+ * @dev: The device.
+ * @req_id: Requester ID for the device.
+ *
+ * Returns: the MSI domain for this device, NULL otherwise
+ */
+struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id)
+{
+	static struct fwnode_handle *handle;
+	int its_id;
+
+	if (!iort_table)
+		return NULL;
+
+	if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
+		return NULL;
+
+	handle = iort_find_domain_token(its_id);
+	if (!handle)
+		return NULL;
+
+	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
+}
+
 void __init iort_table_detect(void)
 {
 	acpi_status status;
diff --git a/include/linux/iort.h b/include/linux/iort.h
index cde6809..d7daba1 100644
--- a/include/linux/iort.h
+++ b/include/linux/iort.h
@@ -20,11 +20,22 @@
 #define __IORT_H__
 
 #include <linux/acpi.h>
+#include <linux/fwnode.h>
+#include <linux/irqdomain.h>
 
+int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
+void iort_deregister_domain_token(int trans_id);
+struct fwnode_handle *iort_find_domain_token(int trans_id);
 #ifdef CONFIG_IORT_TABLE
 void iort_table_detect(void);
+u32 iort_msi_map_rid(struct device *dev, u32 req_id);
+struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
 #else
 static inline void iort_table_detect(void) { }
+static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
+{ return req_id; }
+static inline struct irq_domain *
+iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
 #endif
 
 #endif /* __IORT_H__ */
-- 
1.9.1

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#1461316 — Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling

On Thu, Aug 11, 2016 at 12:06:32PM +0200, Tomasz Nowicki wrote:

[...]

> +/**
> + * iort_register_domain_token() - register domain token and related ITS ID
> + * to the list from where we can get it back later on.
> + * @trans_id: ITS ID.
> + * @fw_node: Domain token.
> + *
> + * Returns: 0 on success, -ENOMEM if no memory when allocating list element
> + */
> +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
> +{
> +	struct iort_its_msi_chip *its_msi_chip;
> +
> +	its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);

I spotted this while reworking my ARM SMMU series, this may sleep
and that's no good given that we call it within the acpi_probe_lock.

Same goes for irq_domain_alloc_fwnode() (that we call in
gic_v2_acpi_init()), we have got to fix this usage, I will see with
Marc what's the best way to do it.

Lorenzo

> +	if (!its_msi_chip)
> +		return -ENOMEM;
> +
> +	its_msi_chip->fw_node = fw_node;
> +	its_msi_chip->translation_id = trans_id;
> +
> +	spin_lock(&iort_msi_chip_lock);
> +	list_add(&its_msi_chip->list, &iort_msi_chip_list);
> +	spin_unlock(&iort_msi_chip_lock);
> +
> +	return 0;
> +}
> +
> +/**
> + * iort_deregister_domain_token() - Deregister domain token based on ITS ID
> + * @trans_id: ITS ID.
> + *
> + * Returns: none.
> + */
> +void iort_deregister_domain_token(int trans_id)
> +{
> +	struct iort_its_msi_chip *its_msi_chip, *t;
> +
> +	spin_lock(&iort_msi_chip_lock);
> +	list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
> +		if (its_msi_chip->translation_id == trans_id) {
> +			list_del(&its_msi_chip->list);
> +			kfree(its_msi_chip);
> +			break;
> +		}
> +	}
> +	spin_unlock(&iort_msi_chip_lock);
> +}
> +
> +/**
> + * iort_find_domain_token() - Find domain token based on given ITS ID
> + * @trans_id: ITS ID.
> + *
> + * Returns: domain token when find on the list, NULL otherwise
> + */
> +struct fwnode_handle *iort_find_domain_token(int trans_id)
> +{
> +	struct fwnode_handle *fw_node = NULL;
> +	struct iort_its_msi_chip *its_msi_chip;
> +
> +	spin_lock(&iort_msi_chip_lock);
> +	list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
> +		if (its_msi_chip->translation_id == trans_id) {
> +			fw_node = its_msi_chip->fw_node;
> +			break;
> +		}
> +	}
> +	spin_unlock(&iort_msi_chip_lock);
> +
> +	return fw_node;
> +}
> +
>  static struct acpi_iort_node *
>  iort_scan_node(enum acpi_iort_node_type type,
>  	       iort_find_node_callback callback, void *context)
> @@ -206,6 +285,96 @@ iort_find_dev_node(struct device *dev)
>  			      iort_match_node_callback, &pbus->dev);
>  }
>  
> +/**
> + * iort_msi_map_rid() - Map a MSI requester ID for a device
> + * @dev: The device for which the mapping is to be done.
> + * @req_id: The device requester ID.
> + *
> + * Returns: mapped MSI RID on success, input requester ID otherwise
> + */
> +u32 iort_msi_map_rid(struct device *dev, u32 req_id)
> +{
> +	struct acpi_iort_node *node;
> +	u32 dev_id;
> +
> +	if (!iort_table)
> +		return req_id;
> +
> +	node = iort_find_dev_node(dev);
> +	if (!node) {
> +		dev_err(dev, "can't find related IORT node\n");
> +		return req_id;
> +	}
> +
> +	iort_node_map_rid(node, req_id, &dev_id, ACPI_IORT_NODE_ITS_GROUP);
> +	return dev_id;
> +}
> +
> +/**
> + * iort_dev_find_its_id() - Find the ITS identifier for a device
> + * @dev: The device.
> + * @idx: Index of the ITS identifier list.
> + * @its_id: ITS identifier.
> + *
> + * Returns: 0 on success, appropriate error value otherwise
> + */
> +static int
> +iort_dev_find_its_id(struct device *dev, u32 req_id, unsigned int idx,
> +		     int *its_id)
> +{
> +	struct acpi_iort_its_group *its;
> +	struct acpi_iort_node *node;
> +
> +	node = iort_find_dev_node(dev);
> +	if (!node) {
> +		dev_err(dev, "can't find related IORT node\n");
> +		return -ENXIO;
> +	}
> +
> +	node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP);
> +	if (!node) {
> +		dev_err(dev, "can't find related ITS node\n");
> +		return -ENXIO;
> +	}
> +
> +	/* Move to ITS specific data */
> +	its = (struct acpi_iort_its_group *)node->node_data;
> +	if (idx > its->its_count) {
> +		dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n",
> +			idx, its->its_count);
> +		return -ENXIO;
> +	}
> +
> +	*its_id = its->identifiers[idx];
> +	return 0;
> +}
> +
> +/**
> + * iort_get_device_domain() - Find MSI domain related to a device
> + * @dev: The device.
> + * @req_id: Requester ID for the device.
> + *
> + * Returns: the MSI domain for this device, NULL otherwise
> + */
> +struct irq_domain *
> +iort_get_device_domain(struct device *dev, u32 req_id)
> +{
> +	static struct fwnode_handle *handle;
> +	int its_id;
> +
> +	if (!iort_table)
> +		return NULL;
> +
> +	if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
> +		return NULL;
> +
> +	handle = iort_find_domain_token(its_id);
> +	if (!handle)
> +		return NULL;
> +
> +	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
> +}
> +
>  void __init iort_table_detect(void)
>  {
>  	acpi_status status;
> diff --git a/include/linux/iort.h b/include/linux/iort.h
> index cde6809..d7daba1 100644
> --- a/include/linux/iort.h
> +++ b/include/linux/iort.h
> @@ -20,11 +20,22 @@
>  #define __IORT_H__
>  
>  #include <linux/acpi.h>
> +#include <linux/fwnode.h>
> +#include <linux/irqdomain.h>
>  
> +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
> +void iort_deregister_domain_token(int trans_id);
> +struct fwnode_handle *iort_find_domain_token(int trans_id);
>  #ifdef CONFIG_IORT_TABLE
>  void iort_table_detect(void);
> +u32 iort_msi_map_rid(struct device *dev, u32 req_id);
> +struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
>  #else
>  static inline void iort_table_detect(void) { }
> +static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
> +{ return req_id; }
> +static inline struct irq_domain *
> +iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
>  #endif
>  
>  #endif /* __IORT_H__ */
> -- 
> 1.9.1
> 

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#1463347 — RE: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling

Hi,

> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Lorenzo
> Pieralisi
> Subject: Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling
> 
> On Thu, Aug 11, 2016 at 12:06:32PM +0200, Tomasz Nowicki wrote:
> 
> [...]
> 
> > +/**
> > + * iort_register_domain_token() - register domain token and related ITS ID
> > + * to the list from where we can get it back later on.
> > + * @trans_id: ITS ID.
> > + * @fw_node: Domain token.
> > + *
> > + * Returns: 0 on success, -ENOMEM if no memory when allocating list element
> > + */
> > +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
> > +{
> > +	struct iort_its_msi_chip *its_msi_chip;
> > +
> > +	its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
> 
> I spotted this while reworking my ARM SMMU series, this may sleep
> and that's no good given that we call it within the acpi_probe_lock.
> 
> Same goes for irq_domain_alloc_fwnode() (that we call in
> gic_v2_acpi_init()), we have got to fix this usage, I will see with
> Marc what's the best way to do it.

If we can ensure that all table device probe entries are created during link stage or early stage.
I think you can safely unlock probe lock before invoking acpi_table_parse() in __acpi_probe_device_table().

Thanks
Lv

> 
> Lorenzo
> 
> > +	if (!its_msi_chip)
> > +		return -ENOMEM;
> > +
> > +	its_msi_chip->fw_node = fw_node;
> > +	its_msi_chip->translation_id = trans_id;
> > +
> > +	spin_lock(&iort_msi_chip_lock);
> > +	list_add(&its_msi_chip->list, &iort_msi_chip_list);
> > +	spin_unlock(&iort_msi_chip_lock);
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * iort_deregister_domain_token() - Deregister domain token based on ITS ID
> > + * @trans_id: ITS ID.
> > + *
> > + * Returns: none.
> > + */
> > +void iort_deregister_domain_token(int trans_id)
> > +{
> > +	struct iort_its_msi_chip *its_msi_chip, *t;
> > +
> > +	spin_lock(&iort_msi_chip_lock);
> > +	list_for_each_entry_safe(its_msi_chip, t, &iort_msi_chip_list, list) {
> > +		if (its_msi_chip->translation_id == trans_id) {
> > +			list_del(&its_msi_chip->list);
> > +			kfree(its_msi_chip);
> > +			break;
> > +		}
> > +	}
> > +	spin_unlock(&iort_msi_chip_lock);
> > +}
> > +
> > +/**
> > + * iort_find_domain_token() - Find domain token based on given ITS ID
> > + * @trans_id: ITS ID.
> > + *
> > + * Returns: domain token when find on the list, NULL otherwise
> > + */
> > +struct fwnode_handle *iort_find_domain_token(int trans_id)
> > +{
> > +	struct fwnode_handle *fw_node = NULL;
> > +	struct iort_its_msi_chip *its_msi_chip;
> > +
> > +	spin_lock(&iort_msi_chip_lock);
> > +	list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
> > +		if (its_msi_chip->translation_id == trans_id) {
> > +			fw_node = its_msi_chip->fw_node;
> > +			break;
> > +		}
> > +	}
> > +	spin_unlock(&iort_msi_chip_lock);
> > +
> > +	return fw_node;
> > +}
> > +
> >  static struct acpi_iort_node *
> >  iort_scan_node(enum acpi_iort_node_type type,
> >  	       iort_find_node_callback callback, void *context)
> > @@ -206,6 +285,96 @@ iort_find_dev_node(struct device *dev)
> >  			      iort_match_node_callback, &pbus->dev);
> >  }
> >
> > +/**
> > + * iort_msi_map_rid() - Map a MSI requester ID for a device
> > + * @dev: The device for which the mapping is to be done.
> > + * @req_id: The device requester ID.
> > + *
> > + * Returns: mapped MSI RID on success, input requester ID otherwise
> > + */
> > +u32 iort_msi_map_rid(struct device *dev, u32 req_id)
> > +{
> > +	struct acpi_iort_node *node;
> > +	u32 dev_id;
> > +
> > +	if (!iort_table)
> > +		return req_id;
> > +
> > +	node = iort_find_dev_node(dev);
> > +	if (!node) {
> > +		dev_err(dev, "can't find related IORT node\n");
> > +		return req_id;
> > +	}
> > +
> > +	iort_node_map_rid(node, req_id, &dev_id, ACPI_IORT_NODE_ITS_GROUP);
> > +	return dev_id;
> > +}
> > +
> > +/**
> > + * iort_dev_find_its_id() - Find the ITS identifier for a device
> > + * @dev: The device.
> > + * @idx: Index of the ITS identifier list.
> > + * @its_id: ITS identifier.
> > + *
> > + * Returns: 0 on success, appropriate error value otherwise
> > + */
> > +static int
> > +iort_dev_find_its_id(struct device *dev, u32 req_id, unsigned int idx,
> > +		     int *its_id)
> > +{
> > +	struct acpi_iort_its_group *its;
> > +	struct acpi_iort_node *node;
> > +
> > +	node = iort_find_dev_node(dev);
> > +	if (!node) {
> > +		dev_err(dev, "can't find related IORT node\n");
> > +		return -ENXIO;
> > +	}
> > +
> > +	node = iort_node_map_rid(node, req_id, NULL, ACPI_IORT_NODE_ITS_GROUP);
> > +	if (!node) {
> > +		dev_err(dev, "can't find related ITS node\n");
> > +		return -ENXIO;
> > +	}
> > +
> > +	/* Move to ITS specific data */
> > +	its = (struct acpi_iort_its_group *)node->node_data;
> > +	if (idx > its->its_count) {
> > +		dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n",
> > +			idx, its->its_count);
> > +		return -ENXIO;
> > +	}
> > +
> > +	*its_id = its->identifiers[idx];
> > +	return 0;
> > +}
> > +
> > +/**
> > + * iort_get_device_domain() - Find MSI domain related to a device
> > + * @dev: The device.
> > + * @req_id: Requester ID for the device.
> > + *
> > + * Returns: the MSI domain for this device, NULL otherwise
> > + */
> > +struct irq_domain *
> > +iort_get_device_domain(struct device *dev, u32 req_id)
> > +{
> > +	static struct fwnode_handle *handle;
> > +	int its_id;
> > +
> > +	if (!iort_table)
> > +		return NULL;
> > +
> > +	if (iort_dev_find_its_id(dev, req_id, 0, &its_id))
> > +		return NULL;
> > +
> > +	handle = iort_find_domain_token(its_id);
> > +	if (!handle)
> > +		return NULL;
> > +
> > +	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
> > +}
> > +
> >  void __init iort_table_detect(void)
> >  {
> >  	acpi_status status;
> > diff --git a/include/linux/iort.h b/include/linux/iort.h
> > index cde6809..d7daba1 100644
> > --- a/include/linux/iort.h
> > +++ b/include/linux/iort.h
> > @@ -20,11 +20,22 @@
> >  #define __IORT_H__
> >
> >  #include <linux/acpi.h>
> > +#include <linux/fwnode.h>
> > +#include <linux/irqdomain.h>
> >
> > +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node);
> > +void iort_deregister_domain_token(int trans_id);
> > +struct fwnode_handle *iort_find_domain_token(int trans_id);
> >  #ifdef CONFIG_IORT_TABLE
> >  void iort_table_detect(void);
> > +u32 iort_msi_map_rid(struct device *dev, u32 req_id);
> > +struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
> >  #else
> >  static inline void iort_table_detect(void) { }
> > +static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
> > +{ return req_id; }
> > +static inline struct irq_domain *
> > +iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
> >  #endif
> >
> >  #endif /* __IORT_H__ */
> > --
> > 1.9.1
> >
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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#1463673 — Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling

On 16/08/16 03:15, Zheng, Lv wrote:
> Hi,
> 
>> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Lorenzo
>> Pieralisi
>> Subject: Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling
>>
>> On Thu, Aug 11, 2016 at 12:06:32PM +0200, Tomasz Nowicki wrote:
>>
>> [...]
>>
>>> +/**
>>> + * iort_register_domain_token() - register domain token and related ITS ID
>>> + * to the list from where we can get it back later on.
>>> + * @trans_id: ITS ID.
>>> + * @fw_node: Domain token.
>>> + *
>>> + * Returns: 0 on success, -ENOMEM if no memory when allocating list element
>>> + */
>>> +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
>>> +{
>>> +	struct iort_its_msi_chip *its_msi_chip;
>>> +
>>> +	its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
>>
>> I spotted this while reworking my ARM SMMU series, this may sleep
>> and that's no good given that we call it within the acpi_probe_lock.
>>
>> Same goes for irq_domain_alloc_fwnode() (that we call in
>> gic_v2_acpi_init()), we have got to fix this usage, I will see with
>> Marc what's the best way to do it.
> 
> If we can ensure that all table device probe entries are created
> during link stage or early stage. I think you can safely unlock probe
> lock before invoking acpi_table_parse() in
> __acpi_probe_device_table().

That'd be quite risky, as this lock is the only thing that protects the
acpi_probe_entry pointer (I really wish the ACPI API was less global
variable happy), and I don't see how we can guarantee to only ever
execute this in a single-threaded environment.

An alternative would be to turn the spinlock into a mutex, which will
allow sleeping, and yet provide the required mutual exclusion.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

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