Date:   Tue, 31 Oct 2017 15:42:15 -0500
From:   Alan Tull <atull@...nel.org>
To:     Moritz Fischer <mdf@...nel.org>
Cc:     Alan Tull <atull@...nel.org>, linux-kernel@...r.kernel.org,
        linux-fpga@...r.kernel.org
Subject: [PATCH 3/3] fpga: bridge: don't use drvdata in common fpga code

Changes to the fpga bridge code to not use drvdata in common code.

Change fpga_bridge_register to not set drvdata.

Change the register/unregister functions parameters to take the
bridge struct:
* int fpga_bridge_register(struct device *dev,
                           struct fpga_bridge *bridge);
* void fpga_bridge_unregister(struct fpga_bridge *bridge);

Change the drivers that call fpga_bridge_register to alloc the struct
fpga_bridge (using devm_kzalloc) and partly fill it, adding name,
ops, and priv.

The rationale is that setting drvdata is fine for DT based devices
that will have one manager, bridge, or region per platform device.
However PCIe based devices may have multiple FPGA mgr/bridge/regions
under one pcie device.  Without these changes, the PCIe solution has
to create an extra device for each child mgr/bridge/region to hold
drvdata.

Signed-off-by: Alan Tull <atull@...nel.org>
Reported-by: Jiuyue Ma <majiuyue@...wei.com>
---
 drivers/fpga/altera-fpga2sdram.c    | 19 +++++++++++++++----
 drivers/fpga/altera-freeze-bridge.c | 17 ++++++++++++++---
 drivers/fpga/altera-hps2fpga.c      | 15 ++++++++++++---
 drivers/fpga/fpga-bridge.c          | 30 +++++++-----------------------
 drivers/fpga/xilinx-pr-decoupler.c  | 14 +++++++++++---
 include/linux/fpga/fpga-bridge.h    |  5 ++---
 6 files changed, 61 insertions(+), 39 deletions(-)

diff --git a/drivers/fpga/altera-fpga2sdram.c b/drivers/fpga/altera-fpga2sdram.c
index d4eeb74..73c7bf6 100644
--- a/drivers/fpga/altera-fpga2sdram.c
+++ b/drivers/fpga/altera-fpga2sdram.c
@@ -106,10 +106,15 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct alt_fpga2sdram_data *priv;
+	struct fpga_bridge *br;
 	u32 enable;
 	struct regmap *sysmgr;
 	int ret = 0;
 
+	br = devm_kzalloc(dev, sizeof(*br), GFP_KERNEL);
+	if (!br)
+		return -ENOMEM;
+
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -131,8 +136,12 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 	/* Get f2s bridge configuration saved in handoff register */
 	regmap_read(sysmgr, SYSMGR_ISWGRP_HANDOFF3, &priv->mask);
 
-	ret = fpga_bridge_register(dev, F2S_BRIDGE_NAME,
-				   &altera_fpga2sdram_br_ops, priv);
+	br->name = F2S_BRIDGE_NAME;
+	br->br_ops = &altera_fpga2sdram_br_ops;
+	br->priv = priv;
+	platform_set_drvdata(pdev, br);
+
+	ret = fpga_bridge_register(dev, br);
 	if (ret)
 		return ret;
 
@@ -146,7 +155,7 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 				 (enable ? "enabling" : "disabling"));
 			ret = _alt_fpga2sdram_enable_set(priv, enable);
 			if (ret) {
-				fpga_bridge_unregister(&pdev->dev);
+				fpga_bridge_unregister(br);
 				return ret;
 			}
 		}
@@ -157,7 +166,9 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 
 static int alt_fpga_bridge_remove(struct platform_device *pdev)
 {
-	fpga_bridge_unregister(&pdev->dev);
+	struct fpga_bridge *br = platform_get_drvdata(pdev);
+
+	fpga_bridge_unregister(br);
 
 	return 0;
 }
diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c
index 6159cfcf..5fd424b 100644
--- a/drivers/fpga/altera-freeze-bridge.c
+++ b/drivers/fpga/altera-freeze-bridge.c
@@ -219,6 +219,7 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = pdev->dev.of_node;
+	struct fpga_bridge *br;
 	void __iomem *base_addr;
 	struct altera_freeze_br_data *priv;
 	struct resource *res;
@@ -227,6 +228,10 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
 	if (!np)
 		return -ENODEV;
 
+	br = devm_kzalloc(dev, sizeof(*br), GFP_KERNEL);
+	if (!br)
+		return -ENOMEM;
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base_addr = devm_ioremap_resource(dev, res);
 	if (IS_ERR(base_addr))
@@ -254,13 +259,19 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
 
 	priv->base_addr = base_addr;
 
-	return fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
-				    &altera_freeze_br_br_ops, priv);
+	br->name = FREEZE_BRIDGE_NAME;
+	br->br_ops = &altera_freeze_br_br_ops;
+	br->priv = priv;
+	platform_set_drvdata(pdev, br);
+
+	return fpga_bridge_register(dev, br);
 }
 
 static int altera_freeze_br_remove(struct platform_device *pdev)
 {
-	fpga_bridge_unregister(&pdev->dev);
+	struct fpga_bridge *br = platform_get_drvdata(pdev);
+
+	fpga_bridge_unregister(br);
 
 	return 0;
 }
diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c
index 406d2f1..4539057 100644
--- a/drivers/fpga/altera-hps2fpga.c
+++ b/drivers/fpga/altera-hps2fpga.c
@@ -139,6 +139,7 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct altera_hps2fpga_data *priv;
 	const struct of_device_id *of_id;
+	struct fpga_bridge *br;
 	u32 enable;
 	int ret;
 
@@ -150,6 +151,10 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 
 	priv = (struct altera_hps2fpga_data *)of_id->data;
 
+	br = devm_kzalloc(dev, sizeof(*br), GFP_KERNEL);
+	if (!br)
+		return -ENOMEM;
+
 	priv->bridge_reset = of_reset_control_get_exclusive_by_index(dev->of_node,
 								     0);
 	if (IS_ERR(priv->bridge_reset)) {
@@ -190,8 +195,12 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 		}
 	}
 
-	ret = fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
-				   priv);
+	br->name = priv->name;
+	br->br_ops = &altera_hps2fpga_br_ops;
+	br->priv = priv;
+	platform_set_drvdata(pdev, br);
+
+	ret = fpga_bridge_register(dev, br);
 err:
 	if (ret)
 		clk_disable_unprepare(priv->clk);
@@ -204,7 +213,7 @@ static int alt_fpga_bridge_remove(struct platform_device *pdev)
 	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
 	struct altera_hps2fpga_data *priv = bridge->priv;
 
-	fpga_bridge_unregister(&pdev->dev);
+	fpga_bridge_unregister(bridge);
 
 	clk_disable_unprepare(priv->clk);
 
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index 15ce9f1..10b582e 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -338,41 +338,30 @@ ATTRIBUTE_GROUPS(fpga_bridge);
  *
  * Return: 0 for success, error code otherwise.
  */
-int fpga_bridge_register(struct device *dev, const char *name,
-			 const struct fpga_bridge_ops *br_ops, void *priv)
+int fpga_bridge_register(struct device *dev, struct fpga_bridge *bridge)
 {
-	struct fpga_bridge *bridge;
+	const char *name;
 	int id, ret = 0;
 
+	name = bridge->name;
 	if (!name || !strlen(name)) {
 		dev_err(dev, "Attempt to register with no name!\n");
 		return -EINVAL;
 	}
 
-	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
-	if (!bridge)
-		return -ENOMEM;
-
 	id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
-	if (id < 0) {
-		ret = id;
-		goto error_kfree;
-	}
+	if (id < 0)
+		return id;
 
 	mutex_init(&bridge->mutex);
 	INIT_LIST_HEAD(&bridge->node);
 
-	bridge->name = name;
-	bridge->br_ops = br_ops;
-	bridge->priv = priv;
-
 	device_initialize(&bridge->dev);
-	bridge->dev.groups = br_ops->groups;
+	bridge->dev.groups = bridge->br_ops->groups;
 	bridge->dev.class = fpga_bridge_class;
 	bridge->dev.parent = dev;
 	bridge->dev.of_node = dev->of_node;
 	bridge->dev.id = id;
-	dev_set_drvdata(dev, bridge);
 
 	ret = dev_set_name(&bridge->dev, "br%d", id);
 	if (ret)
@@ -391,8 +380,6 @@ int fpga_bridge_register(struct device *dev, const char *name,
 
 error_device:
 	ida_simple_remove(&fpga_bridge_ida, id);
-error_kfree:
-	kfree(bridge);
 
 	return ret;
 }
@@ -402,10 +389,8 @@ EXPORT_SYMBOL_GPL(fpga_bridge_register);
  * fpga_bridge_unregister - unregister a fpga bridge driver
  * @dev: FPGA bridge device from pdev
  */
-void fpga_bridge_unregister(struct device *dev)
+void fpga_bridge_unregister(struct fpga_bridge *bridge)
 {
-	struct fpga_bridge *bridge = dev_get_drvdata(dev);
-
 	/*
 	 * If the low level driver provides a method for putting bridge into
 	 * a desired state upon unregister, do it.
@@ -422,7 +407,6 @@ static void fpga_bridge_dev_release(struct device *dev)
 	struct fpga_bridge *bridge = to_fpga_bridge(dev);
 
 	ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
-	kfree(bridge);
 }
 
 static int __init fpga_bridge_dev_init(void)
diff --git a/drivers/fpga/xilinx-pr-decoupler.c b/drivers/fpga/xilinx-pr-decoupler.c
index e359930..317b2fb 100644
--- a/drivers/fpga/xilinx-pr-decoupler.c
+++ b/drivers/fpga/xilinx-pr-decoupler.c
@@ -94,9 +94,14 @@ MODULE_DEVICE_TABLE(of, xlnx_pr_decoupler_of_match);
 static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 {
 	struct xlnx_pr_decoupler_data *priv;
+	struct fpga_bridge *br;
 	int err;
 	struct resource *res;
 
+	br = devm_kzalloc(dev, sizeof(*br), GFP_KERNEL);
+	if (!br)
+		return -ENOMEM;
+
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -120,9 +125,12 @@ static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 
 	clk_disable(priv->clk);
 
-	err = fpga_bridge_register(&pdev->dev, "Xilinx PR Decoupler",
-				   &xlnx_pr_decoupler_br_ops, priv);
+	br->name = "Xilinx PR Decoupler";
+	br->br_ops = &xlnx_pr_decoupler_br_ops;
+	br->priv = priv;
+	platform_set_drvdata(pdev, br);
 
+	err = fpga_bridge_register(&pdev->dev, br);
 	if (err) {
 		dev_err(&pdev->dev, "unable to register Xilinx PR Decoupler");
 		clk_unprepare(priv->clk);
@@ -137,7 +145,7 @@ static int xlnx_pr_decoupler_remove(struct platform_device *pdev)
 	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
 	struct xlnx_pr_decoupler_data *p = bridge->priv;
 
-	fpga_bridge_unregister(&pdev->dev);
+	fpga_bridge_unregister(bridge);
 
 	clk_unprepare(p->clk);
 
diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h
index 65d3311..9e80dbf 100644
--- a/include/linux/fpga/fpga-bridge.h
+++ b/include/linux/fpga/fpga-bridge.h
@@ -60,8 +60,7 @@ int of_fpga_bridge_get_to_list(struct device_node *np,
 			       struct fpga_image_info *info,
 			       struct list_head *bridge_list);
 
-int fpga_bridge_register(struct device *dev, const char *name,
-			 const struct fpga_bridge_ops *br_ops, void *priv);
-void fpga_bridge_unregister(struct device *dev);
+int fpga_bridge_register(struct device *dev, struct fpga_bridge *br);
+void fpga_bridge_unregister(struct fpga_bridge *br);
 
 #endif /* _LINUX_FPGA_BRIDGE_H */
-- 
2.7.4

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