linux-kernel - [PATCH v4 1/5] cdx: Remove cdx controller list from cdx bus system

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Message-ID: <20230826044944.4161017-2-abhijit.gangurde@amd.com>
Date:   Sat, 26 Aug 2023 10:19:40 +0530
From:   Abhijit Gangurde <abhijit.gangurde@....com>
To:     <gregkh@...uxfoundation.org>, <masahiroy@...nel.org>,
        <linux-kernel@...r.kernel.org>
CC:     <Nipun.Gupta@....com>, <nikhil.agarwal@....com>,
        <puneet.gupta@....com>, <git@....com>, <michal.simek@....com>,
        Abhijit Gangurde <abhijit.gangurde@....com>
Subject: [PATCH v4 1/5] cdx: Remove cdx controller list from cdx bus system

Remove xarray list of cdx controller. Instead, use platform bus
to locate the cdx controller using compat string used by cdx
controller platform driver.
Also, use ida to allocate a unique id for the controller.

Signed-off-by: Abhijit Gangurde <abhijit.gangurde@....com>
---
 Changes in v4:
 - Make cdx_controller_ida as static

 Changes in v3:
 - New patch in the series
 - Remove xarray list and use platform bus
 - Use ida to get unique id for controller

 drivers/cdx/cdx.c           | 39 ++++++++++++++++++++++++-------------
 include/linux/cdx/cdx_bus.h |  2 ++
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c
index d2cad4c670a0..600482694161 100644
--- a/drivers/cdx/cdx.c
+++ b/drivers/cdx/cdx.c
@@ -60,7 +60,7 @@
 #include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
-#include <linux/xarray.h>
+#include <linux/idr.h>
 #include <linux/cdx/cdx_bus.h>
 #include <linux/iommu.h>
 #include <linux/dma-map-ops.h>
@@ -70,8 +70,10 @@
 #define CDX_DEFAULT_DMA_MASK	(~0ULL)
 #define MAX_CDX_CONTROLLERS 16
 
-/* CDX controllers registered with the CDX bus */
-static DEFINE_XARRAY_ALLOC(cdx_controllers);
+/* IDA for CDX controllers registered with the CDX bus */
+static DEFINE_IDA(cdx_controller_ida);
+
+static char *compat_node_name = "xlnx,versal-net-cdx";
 
 /**
  * cdx_dev_reset - Reset a CDX device
@@ -384,7 +386,8 @@ static ssize_t rescan_store(const struct bus_type *bus,
 			    const char *buf, size_t count)
 {
 	struct cdx_controller *cdx;
-	unsigned long index;
+	struct platform_device *pd;
+	struct device_node *np;
 	bool val;
 
 	if (kstrtobool(buf, &val) < 0)
@@ -397,12 +400,19 @@ static ssize_t rescan_store(const struct bus_type *bus,
 	cdx_unregister_devices(&cdx_bus_type);
 
 	/* Rescan all the devices */
-	xa_for_each(&cdx_controllers, index, cdx) {
-		int ret;
+	for_each_compatible_node(np, NULL, compat_node_name) {
+		if (!np)
+			return -EINVAL;
 
-		ret = cdx->ops->scan(cdx);
-		if (ret)
-			dev_err(cdx->dev, "cdx bus scanning failed\n");
+		pd = of_find_device_by_node(np);
+		if (!pd)
+			return -EINVAL;
+
+		cdx = platform_get_drvdata(pd);
+		if (cdx && cdx->controller_registered && cdx->ops->scan)
+			cdx->ops->scan(cdx);
+
+		put_device(&pd->dev);
 	}
 
 	return count;
@@ -520,17 +530,19 @@ int cdx_register_controller(struct cdx_controller *cdx)
 {
 	int ret;
 
-	ret = xa_alloc(&cdx_controllers, &cdx->id, cdx,
-		       XA_LIMIT(0, MAX_CDX_CONTROLLERS - 1), GFP_KERNEL);
-	if (ret) {
+	ret = ida_alloc_range(&cdx_controller_ida, 0,  MAX_CDX_CONTROLLERS - 1, GFP_KERNEL);
+	if (ret < 0) {
 		dev_err(cdx->dev,
 			"No free index available. Maximum controllers already registered\n");
 		cdx->id = (u8)MAX_CDX_CONTROLLERS;
 		return ret;
 	}
 
+	cdx->id = ret;
+
 	/* Scan all the devices */
 	cdx->ops->scan(cdx);
+	cdx->controller_registered = true;
 
 	return 0;
 }
@@ -541,8 +553,9 @@ void cdx_unregister_controller(struct cdx_controller *cdx)
 	if (cdx->id >= MAX_CDX_CONTROLLERS)
 		return;
 
+	cdx->controller_registered = false;
 	device_for_each_child(cdx->dev, NULL, cdx_unregister_device);
-	xa_erase(&cdx_controllers, cdx->id);
+	ida_free(&cdx_controller_ida, cdx->id);
 }
 EXPORT_SYMBOL_GPL(cdx_unregister_controller);
 
diff --git a/include/linux/cdx/cdx_bus.h b/include/linux/cdx/cdx_bus.h
index bead71b7bc73..82c27b8c94e1 100644
--- a/include/linux/cdx/cdx_bus.h
+++ b/include/linux/cdx/cdx_bus.h
@@ -63,12 +63,14 @@ struct cdx_ops {
  * @dev: Linux device associated with the CDX controller.
  * @priv: private data
  * @id: Controller ID
+ * @controller_registered: controller registered with bus
  * @ops: CDX controller ops
  */
 struct cdx_controller {
 	struct device *dev;
 	void *priv;
 	u32 id;
+	bool controller_registered;
 	struct cdx_ops *ops;
 };
 
-- 
2.25.1