From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: [PATCH v9 16/16] drivers: acpi: iort: introduce iort_iommu_configure Date: Mon, 21 Nov 2016 10:01:48 +0000 Message-ID: <20161121100148.24769-17-lorenzo.pieralisi@arm.com> References: <20161121100148.24769-1-lorenzo.pieralisi@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161121100148.24769-1-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Marc Zyngier , Tomasz Nowicki , "Rafael J. Wysocki" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Will Deacon , Sinan Kaya , linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jon Masters , Dennis Chen , Prem Mallappa List-Id: linux-acpi@vger.kernel.org DT based systems have a generic kernel API to configure IOMMUs for devices (ie of_iommu_configure()). On ARM based ACPI systems, the of_iommu_configure() equivalent can be implemented atop ACPI IORT kernel API, with the corresponding functions to map device identifiers to IOMMUs and retrieve the corresponding IOMMU operations necessary for DMA operations set-up. By relying on the iommu_fwspec generic kernel infrastructure, implement the IORT based IOMMU configuration for ARM ACPI systems and hook it up in the ACPI kernel layer that implements DMA configuration for a device. Signed-off-by: Lorenzo Pieralisi Acked-by: Rafael J. Wysocki [ACPI core] Reviewed-by: Tomasz Nowicki Tested-by: Hanjun Guo Tested-by: Tomasz Nowicki Cc: Hanjun Guo Cc: Tomasz Nowicki Cc: "Rafael J. Wysocki" --- drivers/acpi/arm64/iort.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/acpi/scan.c | 7 +++- include/linux/acpi_iort.h | 6 +++ 3 files changed, 110 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 6aae49c..47bace8 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -28,6 +28,8 @@ #define IORT_TYPE_MASK(type) (1 << (type)) #define IORT_MSI_TYPE (1 << ACPI_IORT_NODE_ITS_GROUP) +#define IORT_IOMMU_TYPE ((1 << ACPI_IORT_NODE_SMMU) | \ + (1 << ACPI_IORT_NODE_SMMU_V3)) struct iort_its_msi_chip { struct list_head list; @@ -501,6 +503,102 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI); } +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) +{ + u32 *rid = data; + + *rid = alias; + return 0; +} + +static int arm_smmu_iort_xlate(struct device *dev, u32 streamid, + struct fwnode_handle *fwnode, + const struct iommu_ops *ops) +{ + int ret = iommu_fwspec_init(dev, fwnode, ops); + + if (!ret) + ret = iommu_fwspec_add_ids(dev, &streamid, 1); + + return ret; +} + +static const struct iommu_ops *iort_iommu_xlate(struct device *dev, + struct acpi_iort_node *node, + u32 streamid) +{ + const struct iommu_ops *ops = NULL; + int ret = -ENODEV; + struct fwnode_handle *iort_fwnode; + + if (node) { + iort_fwnode = iort_get_fwnode(node); + if (!iort_fwnode) + return NULL; + + ops = iommu_get_instance(iort_fwnode); + if (!ops) + return NULL; + + ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops); + } + + return ret ? NULL : ops; +} + +/** + * iort_iommu_configure - Set-up IOMMU configuration for a device. + * + * @dev: device to configure + * + * Returns: iommu_ops pointer on configuration success + * NULL on configuration failure + */ +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ + struct acpi_iort_node *node, *parent; + const struct iommu_ops *ops = NULL; + u32 streamid = 0; + + if (dev_is_pci(dev)) { + struct pci_bus *bus = to_pci_dev(dev)->bus; + u32 rid; + + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, + &rid); + + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX, + iort_match_node_callback, &bus->dev); + if (!node) + return NULL; + + parent = iort_node_map_rid(node, rid, &streamid, + IORT_IOMMU_TYPE); + + ops = iort_iommu_xlate(dev, parent, streamid); + + } else { + int i = 0; + + node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT, + iort_match_node_callback, dev); + if (!node) + return NULL; + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + + while (parent) { + ops = iort_iommu_xlate(dev, parent, streamid); + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + } + } + + return ops; +} + static void __init acpi_iort_register_irq(int hwirq, const char *name, int trigger, struct resource *res) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 45b5710..80698d3 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -1377,6 +1378,8 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev) */ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) { + const struct iommu_ops *iommu; + /* * Set default coherent_dma_mask to 32 bit. Drivers are expected to * setup the correct supported mask. @@ -1391,11 +1394,13 @@ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) if (!dev->dma_mask) dev->dma_mask = &dev->coherent_dma_mask; + iommu = iort_iommu_configure(dev); + /* * Assume dma valid range starts at 0 and covers the whole * coherent_dma_mask. */ - arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, NULL, + arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, iommu, attr == DEV_DMA_COHERENT); } EXPORT_SYMBOL_GPL(acpi_dma_configure); diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h index 79ba1bb..dcb2b60 100644 --- a/include/linux/acpi_iort.h +++ b/include/linux/acpi_iort.h @@ -34,6 +34,8 @@ void acpi_iort_init(void); bool iort_node_match(u8 type); u32 iort_msi_map_rid(struct device *dev, u32 req_id); struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id); +/* IOMMU interface */ +const struct iommu_ops *iort_iommu_configure(struct device *dev); #else static inline void acpi_iort_init(void) { } static inline bool iort_node_match(u8 type) { return false; } @@ -42,6 +44,10 @@ static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id) static inline struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; } +/* IOMMU interface */ +static inline +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ return NULL; } #endif #define IORT_ACPI_DECLARE(name, table_id, fn) \ -- 2.10.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754115AbcKUKBz (ORCPT ); Mon, 21 Nov 2016 05:01:55 -0500 Received: from foss.arm.com ([217.140.101.70]:54990 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754077AbcKUKBi (ORCPT ); Mon, 21 Nov 2016 05:01:38 -0500 From: Lorenzo Pieralisi To: iommu@lists.linux-foundation.org Cc: Lorenzo Pieralisi , Hanjun Guo , Tomasz Nowicki , "Rafael J. Wysocki" , Will Deacon , Marc Zyngier , Robin Murphy , Joerg Roedel , Jon Masters , Eric Auger , Sinan Kaya , Nate Watterson , Prem Mallappa , Dennis Chen , linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v9 16/16] drivers: acpi: iort: introduce iort_iommu_configure Date: Mon, 21 Nov 2016 10:01:48 +0000 Message-Id: <20161121100148.24769-17-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161121100148.24769-1-lorenzo.pieralisi@arm.com> References: <20161121100148.24769-1-lorenzo.pieralisi@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org DT based systems have a generic kernel API to configure IOMMUs for devices (ie of_iommu_configure()). On ARM based ACPI systems, the of_iommu_configure() equivalent can be implemented atop ACPI IORT kernel API, with the corresponding functions to map device identifiers to IOMMUs and retrieve the corresponding IOMMU operations necessary for DMA operations set-up. By relying on the iommu_fwspec generic kernel infrastructure, implement the IORT based IOMMU configuration for ARM ACPI systems and hook it up in the ACPI kernel layer that implements DMA configuration for a device. Signed-off-by: Lorenzo Pieralisi Acked-by: Rafael J. Wysocki [ACPI core] Reviewed-by: Tomasz Nowicki Tested-by: Hanjun Guo Tested-by: Tomasz Nowicki Cc: Hanjun Guo Cc: Tomasz Nowicki Cc: "Rafael J. Wysocki" --- drivers/acpi/arm64/iort.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/acpi/scan.c | 7 +++- include/linux/acpi_iort.h | 6 +++ 3 files changed, 110 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 6aae49c..47bace8 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -28,6 +28,8 @@ #define IORT_TYPE_MASK(type) (1 << (type)) #define IORT_MSI_TYPE (1 << ACPI_IORT_NODE_ITS_GROUP) +#define IORT_IOMMU_TYPE ((1 << ACPI_IORT_NODE_SMMU) | \ + (1 << ACPI_IORT_NODE_SMMU_V3)) struct iort_its_msi_chip { struct list_head list; @@ -501,6 +503,102 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI); } +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) +{ + u32 *rid = data; + + *rid = alias; + return 0; +} + +static int arm_smmu_iort_xlate(struct device *dev, u32 streamid, + struct fwnode_handle *fwnode, + const struct iommu_ops *ops) +{ + int ret = iommu_fwspec_init(dev, fwnode, ops); + + if (!ret) + ret = iommu_fwspec_add_ids(dev, &streamid, 1); + + return ret; +} + +static const struct iommu_ops *iort_iommu_xlate(struct device *dev, + struct acpi_iort_node *node, + u32 streamid) +{ + const struct iommu_ops *ops = NULL; + int ret = -ENODEV; + struct fwnode_handle *iort_fwnode; + + if (node) { + iort_fwnode = iort_get_fwnode(node); + if (!iort_fwnode) + return NULL; + + ops = iommu_get_instance(iort_fwnode); + if (!ops) + return NULL; + + ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops); + } + + return ret ? NULL : ops; +} + +/** + * iort_iommu_configure - Set-up IOMMU configuration for a device. + * + * @dev: device to configure + * + * Returns: iommu_ops pointer on configuration success + * NULL on configuration failure + */ +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ + struct acpi_iort_node *node, *parent; + const struct iommu_ops *ops = NULL; + u32 streamid = 0; + + if (dev_is_pci(dev)) { + struct pci_bus *bus = to_pci_dev(dev)->bus; + u32 rid; + + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, + &rid); + + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX, + iort_match_node_callback, &bus->dev); + if (!node) + return NULL; + + parent = iort_node_map_rid(node, rid, &streamid, + IORT_IOMMU_TYPE); + + ops = iort_iommu_xlate(dev, parent, streamid); + + } else { + int i = 0; + + node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT, + iort_match_node_callback, dev); + if (!node) + return NULL; + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + + while (parent) { + ops = iort_iommu_xlate(dev, parent, streamid); + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + } + } + + return ops; +} + static void __init acpi_iort_register_irq(int hwirq, const char *name, int trigger, struct resource *res) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 45b5710..80698d3 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -1377,6 +1378,8 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev) */ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) { + const struct iommu_ops *iommu; + /* * Set default coherent_dma_mask to 32 bit. Drivers are expected to * setup the correct supported mask. @@ -1391,11 +1394,13 @@ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) if (!dev->dma_mask) dev->dma_mask = &dev->coherent_dma_mask; + iommu = iort_iommu_configure(dev); + /* * Assume dma valid range starts at 0 and covers the whole * coherent_dma_mask. */ - arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, NULL, + arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, iommu, attr == DEV_DMA_COHERENT); } EXPORT_SYMBOL_GPL(acpi_dma_configure); diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h index 79ba1bb..dcb2b60 100644 --- a/include/linux/acpi_iort.h +++ b/include/linux/acpi_iort.h @@ -34,6 +34,8 @@ void acpi_iort_init(void); bool iort_node_match(u8 type); u32 iort_msi_map_rid(struct device *dev, u32 req_id); struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id); +/* IOMMU interface */ +const struct iommu_ops *iort_iommu_configure(struct device *dev); #else static inline void acpi_iort_init(void) { } static inline bool iort_node_match(u8 type) { return false; } @@ -42,6 +44,10 @@ static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id) static inline struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; } +/* IOMMU interface */ +static inline +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ return NULL; } #endif #define IORT_ACPI_DECLARE(name, table_id, fn) \ -- 2.10.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Mon, 21 Nov 2016 10:01:48 +0000 Subject: [PATCH v9 16/16] drivers: acpi: iort: introduce iort_iommu_configure In-Reply-To: <20161121100148.24769-1-lorenzo.pieralisi@arm.com> References: <20161121100148.24769-1-lorenzo.pieralisi@arm.com> Message-ID: <20161121100148.24769-17-lorenzo.pieralisi@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org DT based systems have a generic kernel API to configure IOMMUs for devices (ie of_iommu_configure()). On ARM based ACPI systems, the of_iommu_configure() equivalent can be implemented atop ACPI IORT kernel API, with the corresponding functions to map device identifiers to IOMMUs and retrieve the corresponding IOMMU operations necessary for DMA operations set-up. By relying on the iommu_fwspec generic kernel infrastructure, implement the IORT based IOMMU configuration for ARM ACPI systems and hook it up in the ACPI kernel layer that implements DMA configuration for a device. Signed-off-by: Lorenzo Pieralisi Acked-by: Rafael J. Wysocki [ACPI core] Reviewed-by: Tomasz Nowicki Tested-by: Hanjun Guo Tested-by: Tomasz Nowicki Cc: Hanjun Guo Cc: Tomasz Nowicki Cc: "Rafael J. Wysocki" --- drivers/acpi/arm64/iort.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/acpi/scan.c | 7 +++- include/linux/acpi_iort.h | 6 +++ 3 files changed, 110 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 6aae49c..47bace8 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -28,6 +28,8 @@ #define IORT_TYPE_MASK(type) (1 << (type)) #define IORT_MSI_TYPE (1 << ACPI_IORT_NODE_ITS_GROUP) +#define IORT_IOMMU_TYPE ((1 << ACPI_IORT_NODE_SMMU) | \ + (1 << ACPI_IORT_NODE_SMMU_V3)) struct iort_its_msi_chip { struct list_head list; @@ -501,6 +503,102 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI); } +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) +{ + u32 *rid = data; + + *rid = alias; + return 0; +} + +static int arm_smmu_iort_xlate(struct device *dev, u32 streamid, + struct fwnode_handle *fwnode, + const struct iommu_ops *ops) +{ + int ret = iommu_fwspec_init(dev, fwnode, ops); + + if (!ret) + ret = iommu_fwspec_add_ids(dev, &streamid, 1); + + return ret; +} + +static const struct iommu_ops *iort_iommu_xlate(struct device *dev, + struct acpi_iort_node *node, + u32 streamid) +{ + const struct iommu_ops *ops = NULL; + int ret = -ENODEV; + struct fwnode_handle *iort_fwnode; + + if (node) { + iort_fwnode = iort_get_fwnode(node); + if (!iort_fwnode) + return NULL; + + ops = iommu_get_instance(iort_fwnode); + if (!ops) + return NULL; + + ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops); + } + + return ret ? NULL : ops; +} + +/** + * iort_iommu_configure - Set-up IOMMU configuration for a device. + * + * @dev: device to configure + * + * Returns: iommu_ops pointer on configuration success + * NULL on configuration failure + */ +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ + struct acpi_iort_node *node, *parent; + const struct iommu_ops *ops = NULL; + u32 streamid = 0; + + if (dev_is_pci(dev)) { + struct pci_bus *bus = to_pci_dev(dev)->bus; + u32 rid; + + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, + &rid); + + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX, + iort_match_node_callback, &bus->dev); + if (!node) + return NULL; + + parent = iort_node_map_rid(node, rid, &streamid, + IORT_IOMMU_TYPE); + + ops = iort_iommu_xlate(dev, parent, streamid); + + } else { + int i = 0; + + node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT, + iort_match_node_callback, dev); + if (!node) + return NULL; + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + + while (parent) { + ops = iort_iommu_xlate(dev, parent, streamid); + + parent = iort_node_get_id(node, &streamid, + IORT_IOMMU_TYPE, i++); + } + } + + return ops; +} + static void __init acpi_iort_register_irq(int hwirq, const char *name, int trigger, struct resource *res) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 45b5710..80698d3 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -1377,6 +1378,8 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev) */ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) { + const struct iommu_ops *iommu; + /* * Set default coherent_dma_mask to 32 bit. Drivers are expected to * setup the correct supported mask. @@ -1391,11 +1394,13 @@ void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) if (!dev->dma_mask) dev->dma_mask = &dev->coherent_dma_mask; + iommu = iort_iommu_configure(dev); + /* * Assume dma valid range starts at 0 and covers the whole * coherent_dma_mask. */ - arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, NULL, + arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, iommu, attr == DEV_DMA_COHERENT); } EXPORT_SYMBOL_GPL(acpi_dma_configure); diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h index 79ba1bb..dcb2b60 100644 --- a/include/linux/acpi_iort.h +++ b/include/linux/acpi_iort.h @@ -34,6 +34,8 @@ void acpi_iort_init(void); bool iort_node_match(u8 type); u32 iort_msi_map_rid(struct device *dev, u32 req_id); struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id); +/* IOMMU interface */ +const struct iommu_ops *iort_iommu_configure(struct device *dev); #else static inline void acpi_iort_init(void) { } static inline bool iort_node_match(u8 type) { return false; } @@ -42,6 +44,10 @@ static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id) static inline struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; } +/* IOMMU interface */ +static inline +const struct iommu_ops *iort_iommu_configure(struct device *dev) +{ return NULL; } #endif #define IORT_ACPI_DECLARE(name, table_id, fn) \ -- 2.10.0