fpga: add device feature list support

Device Feature List (DFL) defines a feature list structure that creates
a linked list of feature headers within the MMIO space to provide an
extensible way of adding features. This patch introduces a kernel module
to provide basic infrastructure to support FPGA devices which implement
the Device Feature List.

Usually there will be different features and their sub features linked into
the DFL. This code provides common APIs for feature enumeration, it creates
a container device (FPGA base region), walks through the DFLs and creates
platform devices for feature devices (Currently it only supports two
different feature devices, FPGA Management Engine (FME) and Port which
the Accelerator Function Unit (AFU) connected to). In order to enumerate
the DFLs, the common APIs required low level driver to provide necessary
enumeration information (e.g. address for each device feature list for
given device) and fill it to the dfl_fpga_enum_info data structure. Please
refer to below description for APIs added for enumeration.

Functions for enumeration information preparation:
 *dfl_fpga_enum_info_alloc
   allocate enumeration information data structure.

 *dfl_fpga_enum_info_add_dfl
   add a device feature list to dfl_fpga_enum_info data structure.

 *dfl_fpga_enum_info_free
   free dfl_fpga_enum_info data structure and related resources.

Functions for feature device enumeration:
 *dfl_fpga_feature_devs_enumerate
   enumerate feature devices and return container device.

 *dfl_fpga_feature_devs_remove
   remove feature devices under given container device.
Signed-off-by: Tim Whisonant <tim.whisonant@intel.com>
Signed-off-by: Enno Luebbers <enno.luebbers@intel.com>
Signed-off-by: Shiva Rao <shiva.rao@intel.com>
Signed-off-by: Christopher Rauer <christopher.rauer@intel.com>
Signed-off-by: Zhang Yi <yi.z.zhang@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/Kconfig

@@ -130,4 +130,20 @@ config OF_FPGA_REGION
 	  Support for loading FPGA images by applying a Device Tree
 	  overlay.
 
+config FPGA_DFL
+	tristate "FPGA Device Feature List (DFL) support"
+	select FPGA_BRIDGE
+	select FPGA_REGION
+	help
+	  Device Feature List (DFL) defines a feature list structure that
+	  creates a linked list of feature headers within the MMIO space
+	  to provide an extensible way of adding features for FPGA.
+	  Driver can walk through the feature headers to enumerate feature
+	  devices (e.g. FPGA Management Engine, Port and Accelerator
+	  Function Unit) and their private features for target FPGA devices.
+
+	  Select this option to enable common support for Field-Programmable
+	  Gate Array (FPGA) solutions which implement Device Feature List.
+	  It provides enumeration APIs and feature device infrastructure.
+
 endif # FPGA

drivers/fpga/Makefile

@@ -28,3 +28,6 @@ obj-$(CONFIG_XILINX_PR_DECOUPLER)	+= xilinx-pr-decoupler.o
 # High Level Interfaces
 obj-$(CONFIG_FPGA_REGION)		+= fpga-region.o
 obj-$(CONFIG_OF_FPGA_REGION)		+= of-fpga-region.o
+
+# FPGA Device Feature List Support
+obj-$(CONFIG_FPGA_DFL)			+= dfl.o

drivers/fpga/dfl.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Driver Header File for FPGA Device Feature List (DFL) Support
+ *
+ * Copyright (C) 2017-2018 Intel Corporation, Inc.
+ *
+ * Authors:
+ *   Kang Luwei <luwei.kang@intel.com>
+ *   Zhang Yi <yi.z.zhang@intel.com>
+ *   Wu Hao <hao.wu@intel.com>
+ *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
+ */
+
+#ifndef __FPGA_DFL_H
+#define __FPGA_DFL_H
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/iopoll.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/fpga/fpga-region.h>
+
+/* maximum supported number of ports */
+#define MAX_DFL_FPGA_PORT_NUM 4
+/* plus one for fme device */
+#define MAX_DFL_FEATURE_DEV_NUM    (MAX_DFL_FPGA_PORT_NUM + 1)
+
+/* Reserved 0x0 for Header Group Register and 0xff for AFU */
+#define FEATURE_ID_FIU_HEADER		0x0
+#define FEATURE_ID_AFU			0xff
+
+#define FME_FEATURE_ID_HEADER		FEATURE_ID_FIU_HEADER
+#define FME_FEATURE_ID_THERMAL_MGMT	0x1
+#define FME_FEATURE_ID_POWER_MGMT	0x2
+#define FME_FEATURE_ID_GLOBAL_IPERF	0x3
+#define FME_FEATURE_ID_GLOBAL_ERR	0x4
+#define FME_FEATURE_ID_PR_MGMT		0x5
+#define FME_FEATURE_ID_HSSI		0x6
+#define FME_FEATURE_ID_GLOBAL_DPERF	0x7
+
+#define PORT_FEATURE_ID_HEADER		FEATURE_ID_FIU_HEADER
+#define PORT_FEATURE_ID_AFU		FEATURE_ID_AFU
+#define PORT_FEATURE_ID_ERROR		0x10
+#define PORT_FEATURE_ID_UMSG		0x11
+#define PORT_FEATURE_ID_UINT		0x12
+#define PORT_FEATURE_ID_STP		0x13
+
+/*
+ * Device Feature Header Register Set
+ *
+ * For FIUs, they all have DFH + GUID + NEXT_AFU as common header registers.
+ * For AFUs, they have DFH + GUID as common header registers.
+ * For private features, they only have DFH register as common header.
+ */
+#define DFH			0x0
+#define GUID_L			0x8
+#define GUID_H			0x10
+#define NEXT_AFU		0x18
+
+#define DFH_SIZE		0x8
+
+/* Device Feature Header Register Bitfield */
+#define DFH_ID			GENMASK_ULL(11, 0)	/* Feature ID */
+#define DFH_ID_FIU_FME		0
+#define DFH_ID_FIU_PORT		1
+#define DFH_REVISION		GENMASK_ULL(15, 12)	/* Feature revision */
+#define DFH_NEXT_HDR_OFST	GENMASK_ULL(39, 16)	/* Offset to next DFH */
+#define DFH_EOL			BIT_ULL(40)		/* End of list */
+#define DFH_TYPE		GENMASK_ULL(63, 60)	/* Feature type */
+#define DFH_TYPE_AFU		1
+#define DFH_TYPE_PRIVATE	3
+#define DFH_TYPE_FIU		4
+
+/* Next AFU Register Bitfield */
+#define NEXT_AFU_NEXT_DFH_OFST	GENMASK_ULL(23, 0)	/* Offset to next AFU */
+
+/* FME Header Register Set */
+#define FME_HDR_DFH		DFH
+#define FME_HDR_GUID_L		GUID_L
+#define FME_HDR_GUID_H		GUID_H
+#define FME_HDR_NEXT_AFU	NEXT_AFU
+#define FME_HDR_CAP		0x30
+#define FME_HDR_PORT_OFST(n)	(0x38 + ((n) * 0x8))
+#define FME_HDR_BITSTREAM_ID	0x60
+#define FME_HDR_BITSTREAM_MD	0x68
+
+/* FME Fab Capability Register Bitfield */
+#define FME_CAP_FABRIC_VERID	GENMASK_ULL(7, 0)	/* Fabric version ID */
+#define FME_CAP_SOCKET_ID	BIT_ULL(8)		/* Socket ID */
+#define FME_CAP_PCIE0_LINK_AVL	BIT_ULL(12)		/* PCIE0 Link */
+#define FME_CAP_PCIE1_LINK_AVL	BIT_ULL(13)		/* PCIE1 Link */
+#define FME_CAP_COHR_LINK_AVL	BIT_ULL(14)		/* Coherent Link */
+#define FME_CAP_IOMMU_AVL	BIT_ULL(16)		/* IOMMU available */
+#define FME_CAP_NUM_PORTS	GENMASK_ULL(19, 17)	/* Number of ports */
+#define FME_CAP_ADDR_WIDTH	GENMASK_ULL(29, 24)	/* Address bus width */
+#define FME_CAP_CACHE_SIZE	GENMASK_ULL(43, 32)	/* cache size in KB */
+#define FME_CAP_CACHE_ASSOC	GENMASK_ULL(47, 44)	/* Associativity */
+
+/* FME Port Offset Register Bitfield */
+/* Offset to port device feature header */
+#define FME_PORT_OFST_DFH_OFST	GENMASK_ULL(23, 0)
+/* PCI Bar ID for this port */
+#define FME_PORT_OFST_BAR_ID	GENMASK_ULL(34, 32)
+/* AFU MMIO access permission. 1 - VF, 0 - PF. */
+#define FME_PORT_OFST_ACC_CTRL	BIT_ULL(55)
+#define FME_PORT_OFST_ACC_PF	0
+#define FME_PORT_OFST_ACC_VF	1
+#define FME_PORT_OFST_IMP	BIT_ULL(60)
+
+/* PORT Header Register Set */
+#define PORT_HDR_DFH		DFH
+#define PORT_HDR_GUID_L		GUID_L
+#define PORT_HDR_GUID_H		GUID_H
+#define PORT_HDR_NEXT_AFU	NEXT_AFU
+#define PORT_HDR_CAP		0x30
+#define PORT_HDR_CTRL		0x38
+
+/* Port Capability Register Bitfield */
+#define PORT_CAP_PORT_NUM	GENMASK_ULL(1, 0)	/* ID of this port */
+#define PORT_CAP_MMIO_SIZE	GENMASK_ULL(23, 8)	/* MMIO size in KB */
+#define PORT_CAP_SUPP_INT_NUM	GENMASK_ULL(35, 32)	/* Interrupts num */
+
+/* Port Control Register Bitfield */
+#define PORT_CTRL_SFTRST	BIT_ULL(0)		/* Port soft reset */
+/* Latency tolerance reporting. '1' >= 40us, '0' < 40us.*/
+#define PORT_CTRL_LATENCY	BIT_ULL(2)
+#define PORT_CTRL_SFTRST_ACK	BIT_ULL(4)		/* HW ack for reset */
+
+/**
+ * struct dfl_feature - sub feature of the feature devices
+ *
+ * @id: sub feature id.
+ * @resource_index: each sub feature has one mmio resource for its registers.
+ *		    this index is used to find its mmio resource from the
+ *		    feature dev (platform device)'s reources.
+ * @ioaddr: mapped mmio resource address.
+ */
+struct dfl_feature {
+	u64 id;
+	int resource_index;
+	void __iomem *ioaddr;
+};
+
+/**
+ * struct dfl_feature_platform_data - platform data for feature devices
+ *
+ * @node: node to link feature devs to container device's port_dev_list.
+ * @lock: mutex to protect platform data.
+ * @dev: ptr to platform device linked with this platform data.
+ * @dfl_cdev: ptr to container device.
+ * @disable_count: count for port disable.
+ * @num: number for sub features.
+ * @features: sub features of this feature dev.
+ */
+struct dfl_feature_platform_data {
+	struct list_head node;
+	struct mutex lock;
+	struct platform_device *dev;
+	struct dfl_fpga_cdev *dfl_cdev;
+	unsigned int disable_count;
+
+	int num;
+	struct dfl_feature features[0];
+};
+
+#define DFL_FPGA_FEATURE_DEV_FME		"dfl-fme"
+#define DFL_FPGA_FEATURE_DEV_PORT		"dfl-port"
+
+static inline int dfl_feature_platform_data_size(const int num)
+{
+	return sizeof(struct dfl_feature_platform_data) +
+		num * sizeof(struct dfl_feature);
+}
+
+#define dfl_fpga_dev_for_each_feature(pdata, feature)			    \
+	for ((feature) = (pdata)->features;				    \
+	   (feature) < (pdata)->features + (pdata)->num; (feature)++)
+
+static inline
+struct dfl_feature *dfl_get_feature_by_id(struct device *dev, u64 id)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	struct dfl_feature *feature;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature)
+		if (feature->id == id)
+			return feature;
+
+	return NULL;
+}
+
+static inline
+void __iomem *dfl_get_feature_ioaddr_by_id(struct device *dev, u64 id)
+{
+	struct dfl_feature *feature = dfl_get_feature_by_id(dev, id);
+
+	if (feature && feature->ioaddr)
+		return feature->ioaddr;
+
+	WARN_ON(1);
+	return NULL;
+}
+
+static inline bool dfl_feature_is_fme(void __iomem *base)
+{
+	u64 v = readq(base + DFH);
+
+	return (FIELD_GET(DFH_TYPE, v) == DFH_TYPE_FIU) &&
+		(FIELD_GET(DFH_ID, v) == DFH_ID_FIU_FME);
+}
+
+static inline bool dfl_feature_is_port(void __iomem *base)
+{
+	u64 v = readq(base + DFH);
+
+	return (FIELD_GET(DFH_TYPE, v) == DFH_TYPE_FIU) &&
+		(FIELD_GET(DFH_ID, v) == DFH_ID_FIU_PORT);
+}
+
+/**
+ * struct dfl_fpga_enum_info - DFL FPGA enumeration information
+ *
+ * @dev: parent device.
+ * @dfls: list of device feature lists.
+ */
+struct dfl_fpga_enum_info {
+	struct device *dev;
+	struct list_head dfls;
+};
+
+/**
+ * struct dfl_fpga_enum_dfl - DFL FPGA enumeration device feature list info
+ *
+ * @start: base address of this device feature list.
+ * @len: size of this device feature list.
+ * @ioaddr: mapped base address of this device feature list.
+ * @node: node in list of device feature lists.
+ */
+struct dfl_fpga_enum_dfl {
+	resource_size_t start;
+	resource_size_t len;
+
+	void __iomem *ioaddr;
+
+	struct list_head node;
+};
+
+struct dfl_fpga_enum_info *dfl_fpga_enum_info_alloc(struct device *dev);
+int dfl_fpga_enum_info_add_dfl(struct dfl_fpga_enum_info *info,
+			       resource_size_t start, resource_size_t len,
+			       void __iomem *ioaddr);
+void dfl_fpga_enum_info_free(struct dfl_fpga_enum_info *info);
+
+/**
+ * struct dfl_fpga_cdev - container device of DFL based FPGA
+ *
+ * @parent: parent device of this container device.
+ * @region: base fpga region.
+ * @fme_dev: FME feature device under this container device.
+ * @lock: mutex lock to protect the port device list.
+ * @port_dev_list: list of all port feature devices under this container device.
+ */
+struct dfl_fpga_cdev {
+	struct device *parent;
+	struct fpga_region *region;
+	struct device *fme_dev;
+	struct mutex lock;
+	struct list_head port_dev_list;
+};
+
+struct dfl_fpga_cdev *
+dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info);
+void dfl_fpga_feature_devs_remove(struct dfl_fpga_cdev *cdev);
+
+#endif /* __FPGA_DFL_H */