Message-Id: <1594791498-14495-3-git-send-email-yilun.xu@intel.com>
Date:   Wed, 15 Jul 2020 13:38:18 +0800
From:   Xu Yilun <yilun.xu@...el.com>
To:     mdf@...nel.org, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     trix@...hat.com, lgoncalv@...hat.com,
        Xu Yilun <yilun.xu@...el.com>, Wu Hao <hao.wu@...el.com>,
        Matthew Gerlach <matthew.gerlach@...ux.intel.com>,
        Russ Weight <russell.h.weight@...el.com>
Subject: [PATCH 2/2] fpga: dfl: create a dfl bus type to support DFL devices

A new bus type "dfl" is introduced for private features which are not
initialized by DFL feature drivers (dfl-fme & dfl-afu drivers). So these
private features could be handled by separate driver modules.

DFL framework will create DFL devices on enumeration. DFL drivers could
be registered on this bus to match these DFL devices. They are matched by
dfl type & feature_id.

Signed-off-by: Xu Yilun <yilun.xu@...el.com>
Signed-off-by: Wu Hao <hao.wu@...el.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@...el.com>
---
 Documentation/ABI/testing/sysfs-bus-dfl |  15 ++
 drivers/fpga/dfl.c                      | 248 ++++++++++++++++++++++++++++++--
 drivers/fpga/dfl.h                      |  85 +++++++++++
 3 files changed, 340 insertions(+), 8 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-dfl

diff --git a/Documentation/ABI/testing/sysfs-bus-dfl b/Documentation/ABI/testing/sysfs-bus-dfl
new file mode 100644
index 0000000..cd00abc
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-dfl
@@ -0,0 +1,15 @@
+What:		/sys/bus/dfl/devices/.../type
+Date:		March 2020
+KernelVersion:	5.7
+Contact:	Xu Yilun <yilun.xu@...el.com>
+Description:	Read-only. It returns type of DFL FIU of the device. Now DFL
+		supports 2 FIU types, 0 for FME, 1 for PORT.
+		Format: 0x%x
+
+What:		/sys/bus/dfl/devices/.../feature_id
+Date:		March 2020
+KernelVersion:	5.7
+Contact:	Xu Yilun <yilun.xu@...el.com>
+Description:	Read-only. It returns feature identifier local to its DFL FIU
+		type.
+		Format: 0x%llx
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 7dc6411..93f9d6d 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -30,12 +30,6 @@ static DEFINE_MUTEX(dfl_id_mutex);
  * index to dfl_chardevs table. If no chardev support just set devt_type
  * as one invalid index (DFL_FPGA_DEVT_MAX).
  */
-enum dfl_id_type {
-	FME_ID,		/* fme id allocation and mapping */
-	PORT_ID,	/* port id allocation and mapping */
-	DFL_ID_MAX,
-};
-
 enum dfl_fpga_devt_type {
 	DFL_FPGA_DEVT_FME,
 	DFL_FPGA_DEVT_PORT,
@@ -255,6 +249,228 @@ static bool is_header_feature(struct dfl_feature *feature)
 	return feature->id == FEATURE_ID_FIU_HEADER;
 }
 
+static const struct dfl_device_id *
+dfl_match_one_device(const struct dfl_device_id *id,
+		     struct dfl_device *dfl_dev)
+{
+	if (id->type == dfl_dev->type &&
+	    id->feature_id == dfl_dev->feature_id)
+		return id;
+
+	return NULL;
+}
+
+static int dfl_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);
+	struct dfl_driver *dfl_drv = to_dfl_drv(drv);
+	const struct dfl_device_id *id_entry = dfl_drv->id_table;
+
+	while (id_entry->feature_id) {
+		if (dfl_match_one_device(id_entry, dfl_dev)) {
+			dfl_dev->id_entry = id_entry;
+			return 1;
+		}
+		id_entry++;
+	}
+
+	return 0;
+}
+
+static int dfl_bus_probe(struct device *dev)
+{
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);
+	struct dfl_driver *dfl_drv = to_dfl_drv(dev->driver);
+
+	return dfl_drv->probe(dfl_dev);
+}
+
+static int dfl_bus_remove(struct device *dev)
+{
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);
+	struct dfl_driver *dfl_drv = to_dfl_drv(dev->driver);
+
+	if (dfl_drv->remove)
+		dfl_drv->remove(dfl_dev);
+
+	return 0;
+}
+
+static int dfl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);
+
+	if (add_uevent_var(env, "MODALIAS=dfl:%08x:%016llx",
+			   dfl_dev->type, dfl_dev->feature_id))
+		return -ENOMEM;
+
+	return 0;
+}
+
+/* show dfl info fields */
+#define dfl_info_attr(field, format_string)				\
+static ssize_t								\
+field##_show(struct device *dev, struct device_attribute *attr,		\
+	     char *buf)							\
+{									\
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);			\
+									\
+	return sprintf(buf, format_string, dfl_dev->field);		\
+}									\
+static DEVICE_ATTR_RO(field)
+
+dfl_info_attr(type, "0x%x\n");
+dfl_info_attr(feature_id, "0x%llx\n");
+
+static struct attribute *dfl_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_feature_id.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(dfl_dev);
+
+static struct bus_type dfl_bus_type = {
+	.name		= "dfl",
+	.match		= dfl_bus_match,
+	.probe		= dfl_bus_probe,
+	.remove		= dfl_bus_remove,
+	.uevent		= dfl_bus_uevent,
+	.dev_groups	= dfl_dev_groups,
+};
+
+static void release_dfl_dev(struct device *dev)
+{
+	struct dfl_device *dfl_dev = to_dfl_dev(dev);
+
+	release_resource(&dfl_dev->mmio_res);
+	kfree(dfl_dev->irqs);
+	kfree(dfl_dev);
+}
+
+static struct dfl_device *
+dfl_dev_add(struct dfl_feature_platform_data *pdata,
+	    struct dfl_feature *feature)
+{
+	struct platform_device *pdev = pdata->dev;
+	struct dfl_device *dfl_dev;
+	int i, ret;
+
+	dfl_dev = kzalloc(sizeof(*dfl_dev), GFP_KERNEL);
+	if (!dfl_dev)
+		return ERR_PTR(-ENOMEM);
+
+	dfl_dev->cdev = pdata->dfl_cdev;
+
+	dfl_dev->mmio_res.parent = &pdev->resource[feature->resource_index];
+	dfl_dev->mmio_res.flags = IORESOURCE_MEM;
+	dfl_dev->mmio_res.start =
+		pdev->resource[feature->resource_index].start;
+	dfl_dev->mmio_res.end = pdev->resource[feature->resource_index].end;
+
+	/* then add irq resource */
+	if (feature->nr_irqs) {
+		dfl_dev->irqs = kcalloc(feature->nr_irqs,
+					sizeof(*dfl_dev->irqs), GFP_KERNEL);
+		if (!dfl_dev->irqs) {
+			ret = -ENOMEM;
+			goto free_dfl_dev;
+		}
+
+		for (i = 0; i < feature->nr_irqs; i++)
+			dfl_dev->irqs[i] = feature->irq_ctx[i].irq;
+
+		dfl_dev->num_irqs = feature->nr_irqs;
+	}
+
+	dfl_dev->type = feature_dev_id_type(pdev);
+	dfl_dev->feature_id = (unsigned long long)feature->id;
+
+	dfl_dev->dev.parent  = &pdev->dev;
+	dfl_dev->dev.bus     = &dfl_bus_type;
+	dfl_dev->dev.release = release_dfl_dev;
+	dev_set_name(&dfl_dev->dev, "%s.%d", dev_name(&pdev->dev),
+		     feature->index);
+
+	dfl_dev->mmio_res.name = dev_name(&dfl_dev->dev);
+	ret = insert_resource(dfl_dev->mmio_res.parent, &dfl_dev->mmio_res);
+	if (ret) {
+		dev_err(&pdev->dev, "%s failed to claim resource: %pR\n",
+			dev_name(&dfl_dev->dev), &dfl_dev->mmio_res);
+		goto free_irqs;
+	}
+
+	ret = device_register(&dfl_dev->dev);
+	if (ret) {
+		put_device(&dfl_dev->dev);
+		return ERR_PTR(ret);
+	}
+
+	dev_info(&pdev->dev, "add dfl_dev: %s\n",
+		 dev_name(&dfl_dev->dev));
+	return dfl_dev;
+
+free_irqs:
+	kfree(dfl_dev->irqs);
+free_dfl_dev:
+	kfree(dfl_dev);
+	return ERR_PTR(ret);
+}
+
+static void dfl_devs_uinit(struct dfl_feature_platform_data *pdata)
+{
+	struct dfl_device *dfl_dev;
+	struct dfl_feature *feature;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
+		if (!feature->ioaddr && feature->priv) {
+			dfl_dev = feature->priv;
+			device_unregister(&dfl_dev->dev);
+			feature->priv = NULL;
+		}
+	}
+}
+
+static int dfl_devs_init(struct platform_device *pdev)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_feature *feature;
+	struct dfl_device *dfl_dev;
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
+		if (feature->ioaddr || feature->priv)
+			continue;
+
+		dfl_dev = dfl_dev_add(pdata, feature);
+		if (IS_ERR(dfl_dev)) {
+			dfl_devs_uinit(pdata);
+			return PTR_ERR(dfl_dev);
+		}
+
+		feature->priv = dfl_dev;
+	}
+
+	return 0;
+}
+
+int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
+{
+	if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
+		return -EINVAL;
+
+	dfl_drv->drv.owner = owner;
+	dfl_drv->drv.bus = &dfl_bus_type;
+
+	return driver_register(&dfl_drv->drv);
+}
+EXPORT_SYMBOL(__dfl_driver_register);
+
+void dfl_driver_unregister(struct dfl_driver *dfl_drv)
+{
+	driver_unregister(&dfl_drv->drv);
+}
+EXPORT_SYMBOL(dfl_driver_unregister);
+
 /**
  * dfl_fpga_dev_feature_uinit - uinit for sub features of dfl feature device
  * @pdev: feature device.
@@ -264,12 +480,15 @@ void dfl_fpga_dev_feature_uinit(struct platform_device *pdev)
 	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct dfl_feature *feature;
 
-	dfl_fpga_dev_for_each_feature(pdata, feature)
+	dfl_devs_uinit(pdata);
+
+	dfl_fpga_dev_for_each_feature(pdata, feature) {
 		if (feature->ops) {
 			if (feature->ops->uinit)
 				feature->ops->uinit(pdev, feature);
 			feature->ops = NULL;
 		}
+	}
 }
 EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_uinit);
 
@@ -348,6 +567,10 @@ int dfl_fpga_dev_feature_init(struct platform_device *pdev,
 		drv++;
 	}
 
+	ret = dfl_devs_init(pdev);
+	if (ret)
+		goto exit;
+
 	return 0;
 exit:
 	dfl_fpga_dev_feature_uinit(pdev);
@@ -553,6 +776,8 @@ static int build_info_commit_dev(struct build_feature_devs_info *binfo)
 		struct dfl_feature_irq_ctx *ctx;
 		unsigned int i;
 
+		feature->index = index;
+
 		/* save resource information for each feature */
 		feature->dev = fdev;
 		feature->id = finfo->fid;
@@ -1295,11 +1520,17 @@ static int __init dfl_fpga_init(void)
 {
 	int ret;
 
+	ret = bus_register(&dfl_bus_type);
+	if (ret)
+		return ret;
+
 	dfl_ids_init();
 
 	ret = dfl_chardev_init();
-	if (ret)
+	if (ret) {
 		dfl_ids_destroy();
+		bus_unregister(&dfl_bus_type);
+	}
 
 	return ret;
 }
@@ -1637,6 +1868,7 @@ static void __exit dfl_fpga_exit(void)
 {
 	dfl_chardev_uinit();
 	dfl_ids_destroy();
+	bus_unregister(&dfl_bus_type);
 }
 
 module_init(dfl_fpga_init);
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index f605c28..d00aa1c 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -229,6 +229,10 @@ struct dfl_feature_irq_ctx {
  *
  * @dev: ptr to pdev of the feature device which has the sub feature.
  * @id: sub feature id.
+ * @index: unique identifier for an sub feature within the feature device.
+ *	   It is possible that multiply sub features with same feature id are
+ *	   listed in one feature device. So an incremental index (start from 0)
+ *	   is needed to identify each sub feature.
  * @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.
@@ -241,6 +245,7 @@ struct dfl_feature_irq_ctx {
 struct dfl_feature {
 	struct platform_device *dev;
 	u64 id;
+	int index;
 	int resource_index;
 	void __iomem *ioaddr;
 	struct dfl_feature_irq_ctx *irq_ctx;
@@ -515,4 +520,84 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
 			       struct dfl_feature *feature,
 			       unsigned long arg);
 
+/**
+ * enum dfl_id_type - define the DFL FIU types
+ */
+enum dfl_id_type {
+	FME_ID,
+	PORT_ID,
+	DFL_ID_MAX,
+};
+
+/**
+ * struct dfl_device_id -  dfl device identifier
+ * @type: Type of DFL FIU of the device. See enum dfl_id_type.
+ * @feature_id: 64 bits feature identifier local to its DFL FIU type.
+ * @driver_data: Driver specific data
+ */
+struct dfl_device_id {
+	unsigned int type;
+	unsigned long long feature_id;
+	unsigned long driver_data;
+};
+
+/**
+ * struct dfl_device - represent an dfl device on dfl bus
+ *
+ * @dev: Generic device interface.
+ * @type: Type of DFL FIU of the device. See enum dfl_id_type.
+ * @feature_id: 64 bits feature identifier local to its DFL FIU type.
+ * @mmio_res: MMIO resource of this dfl device.
+ * @irqs: List of Linux IRQ numbers of this dfl device.
+ * @num_irqs: number of IRQs supported by this dfl device.
+ * @cdev: pointer to DFL FPGA container device this dfl device belongs to.
+ * @id_entry: matched id entry in dfl driver's id table.
+ */
+struct dfl_device {
+	struct device dev;
+	unsigned int type;
+	unsigned long long feature_id;
+	struct resource mmio_res;
+	int *irqs;
+	unsigned int num_irqs;
+	struct dfl_fpga_cdev *cdev;
+	const struct dfl_device_id *id_entry;
+};
+
+/**
+ * struct dfl_driver - represent an dfl device driver
+ *
+ * @drv: Driver model structure.
+ * @id_table: Pointer to table of device IDs the driver is interested in.
+ * @probe: Callback for device binding.
+ * @remove: Callback for device unbinding.
+ */
+struct dfl_driver {
+	struct device_driver drv;
+	const struct dfl_device_id *id_table;
+
+	int (*probe)(struct dfl_device *dfl_dev);
+	int (*remove)(struct dfl_device *dfl_dev);
+};
+
+#define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
+#define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
+
+/*
+ * use a macro to avoid include chaining to get THIS_MODULE
+ */
+#define dfl_driver_register(drv) \
+	__dfl_driver_register(drv, THIS_MODULE)
+int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner);
+void dfl_driver_unregister(struct dfl_driver *dfl_drv);
+
+/* module_dfl_driver() - Helper macro for drivers that don't do
+ * anything special in module init/exit.  This eliminates a lot of
+ * boilerplate.  Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit()
+ */
+#define module_dfl_driver(__dfl_driver) \
+	module_driver(__dfl_driver, dfl_driver_register, \
+		      dfl_driver_unregister)
+
 #endif /* __FPGA_DFL_H */
-- 
2.7.4

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