Re: [PATCH v12 2/3] fpga: bridge: Use standard dev_release for class driver
From: Xu Yilun
Date: Sat Oct 09 2021 - 04:23:05 EST
On Tue, Sep 14, 2021 at 02:43:26PM -0700, Russ Weight wrote:
> The FPGA bridge class driver data structure is being treated as a
> managed resource instead of using the standard dev_release call-back
> function to release the class data structure. This change removes
> the managed resource code and combines the create() and register()
> functions into a single register() function.
>
> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> Reviewed-by: Xu Yilun <yilun.xu@xxxxxxxxx>
Acked-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> ---
> v12:
> - No change
> v11:
> - Rebased to latest linux-next (no conflicts)
> v10:
> - Removed the fpga_bridge_register_full() function, because there is
> not need for it yet. Updated the documentation and commit message
> accordingly.
> v9:
> - Cleaned up documentation for the FPGA Bridge register functions
> - Renamed fpga_bridge_register() to fpga_bridge_register_full()
> - Renamed fpga_bridge_register_simple() to fpga_bridge_register()
> v8:
> - Added reviewed-by tag.
> - Updated Documentation/driver-api/fpga/fpga-bridge.rst documentation.
> v7:
> - Update the commit message to describe the new parameters for the
> fpga_bridge_register() function and to mention the
> fpga_bridge_register_simple() function.
> - Fix function prototypes in header file to rename dev to parent.
> - Some cleanup of comments.
> - Update function definitions/prototypes to apply const to the new info
> parameter.
> - Verify that info->br_ops is non-null in register functions.
> v6:
> - Changed fpga_bridge_register() parameters to accept an info data
> structure to provide flexibility in passing optional parameters.
> - Added fpga_bridge_register_simple() function to support current
> parameters for users that don't require the use of optional
> parameters.
> v5:
> - Rebased on top of recently accepted patches.
> v4:
> - Restore the previous format for the Return value in the comment header
> for fpga_bridge_register()
> v3:
> - Cleaned up comment header for fpga_bridge_register()
> - Fix error return values for fpga_bridge_register()
> v2:
> - No changes
> ---
> Documentation/driver-api/fpga/fpga-bridge.rst | 6 +-
> drivers/fpga/altera-fpga2sdram.c | 12 +-
> drivers/fpga/altera-freeze-bridge.c | 10 +-
> drivers/fpga/altera-hps2fpga.c | 12 +-
> drivers/fpga/dfl-fme-br.c | 10 +-
> drivers/fpga/fpga-bridge.c | 122 ++++--------------
> drivers/fpga/xilinx-pr-decoupler.c | 17 +--
> include/linux/fpga/fpga-bridge.h | 30 +++--
> 8 files changed, 74 insertions(+), 145 deletions(-)
>
> diff --git a/Documentation/driver-api/fpga/fpga-bridge.rst b/Documentation/driver-api/fpga/fpga-bridge.rst
> index 8d650b4e2ce6..604208534095 100644
> --- a/Documentation/driver-api/fpga/fpga-bridge.rst
> +++ b/Documentation/driver-api/fpga/fpga-bridge.rst
> @@ -6,8 +6,7 @@ API to implement a new FPGA bridge
>
> * struct fpga_bridge - The FPGA Bridge structure
> * struct fpga_bridge_ops - Low level Bridge driver ops
> -* devm_fpga_bridge_create() - Allocate and init a bridge struct
> -* fpga_bridge_register() - Register a bridge
> +* fpga_bridge_register() - Create and register a bridge
> * fpga_bridge_unregister() - Unregister a bridge
>
> .. kernel-doc:: include/linux/fpga/fpga-bridge.h
> @@ -16,9 +15,6 @@ API to implement a new FPGA bridge
> .. kernel-doc:: include/linux/fpga/fpga-bridge.h
> :functions: fpga_bridge_ops
>
> -.. kernel-doc:: drivers/fpga/fpga-bridge.c
> - :functions: devm_fpga_bridge_create
> -
> .. kernel-doc:: drivers/fpga/fpga-bridge.c
> :functions: fpga_bridge_register
>
> diff --git a/drivers/fpga/altera-fpga2sdram.c b/drivers/fpga/altera-fpga2sdram.c
> index a78e49c63c64..66063507116b 100644
> --- a/drivers/fpga/altera-fpga2sdram.c
> +++ b/drivers/fpga/altera-fpga2sdram.c
> @@ -121,17 +121,13 @@ 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);
>
> - br = devm_fpga_bridge_create(dev, F2S_BRIDGE_NAME,
> - &altera_fpga2sdram_br_ops, priv);
> - if (!br)
> - return -ENOMEM;
> + br = fpga_bridge_register(dev, F2S_BRIDGE_NAME,
> + &altera_fpga2sdram_br_ops, priv);
> + if (IS_ERR(br))
> + return PTR_ERR(mgr);
>
> platform_set_drvdata(pdev, br);
>
> - ret = fpga_bridge_register(br);
> - if (ret)
> - return ret;
> -
> dev_info(dev, "driver initialized with handoff %08x\n", priv->mask);
>
> if (!of_property_read_u32(dev->of_node, "bridge-enable", &enable)) {
> diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c
> index 7d22a44d652e..445f4b011167 100644
> --- a/drivers/fpga/altera-freeze-bridge.c
> +++ b/drivers/fpga/altera-freeze-bridge.c
> @@ -246,14 +246,14 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
>
> priv->base_addr = base_addr;
>
> - br = devm_fpga_bridge_create(dev, FREEZE_BRIDGE_NAME,
> - &altera_freeze_br_br_ops, priv);
> - if (!br)
> - return -ENOMEM;
> + br = fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
> + &altera_freeze_br_br_ops, priv);
> + if (IS_ERR(br))
> + return PTR_ERR(br);
>
> platform_set_drvdata(pdev, br);
>
> - return fpga_bridge_register(br);
> + return 0;
> }
>
> static int altera_freeze_br_remove(struct platform_device *pdev)
> diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c
> index 77b95f251821..aa758426c22b 100644
> --- a/drivers/fpga/altera-hps2fpga.c
> +++ b/drivers/fpga/altera-hps2fpga.c
> @@ -180,19 +180,15 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
> }
> }
>
> - br = devm_fpga_bridge_create(dev, priv->name,
> - &altera_hps2fpga_br_ops, priv);
> - if (!br) {
> - ret = -ENOMEM;
> + br = fpga_bridge_register(dev, priv->name,
> + &altera_hps2fpga_br_ops, priv);
> + if (IS_ERR(br)) {
> + ret = PTR_ERR(br);
> goto err;
> }
>
> platform_set_drvdata(pdev, br);
>
> - ret = fpga_bridge_register(br);
> - if (ret)
> - goto err;
> -
> return 0;
>
> err:
> diff --git a/drivers/fpga/dfl-fme-br.c b/drivers/fpga/dfl-fme-br.c
> index 3ff9f3a687ce..808d1f4d76df 100644
> --- a/drivers/fpga/dfl-fme-br.c
> +++ b/drivers/fpga/dfl-fme-br.c
> @@ -68,14 +68,14 @@ static int fme_br_probe(struct platform_device *pdev)
>
> priv->pdata = dev_get_platdata(dev);
>
> - br = devm_fpga_bridge_create(dev, "DFL FPGA FME Bridge",
> - &fme_bridge_ops, priv);
> - if (!br)
> - return -ENOMEM;
> + br = fpga_bridge_register(dev, "DFL FPGA FME Bridge",
> + &fme_bridge_ops, priv);
> + if (IS_ERR(br))
> + return PTR_ERR(br);
>
> platform_set_drvdata(pdev, br);
>
> - return fpga_bridge_register(br);
> + return 0;
> }
>
> static int fme_br_remove(struct platform_device *pdev)
> diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
> index 798f55670646..16f2b164a178 100644
> --- a/drivers/fpga/fpga-bridge.c
> +++ b/drivers/fpga/fpga-bridge.c
> @@ -312,36 +312,41 @@ static struct attribute *fpga_bridge_attrs[] = {
> ATTRIBUTE_GROUPS(fpga_bridge);
>
> /**
> - * fpga_bridge_create - create and initialize a struct fpga_bridge
> + * fpga_bridge_register - create and register an FPGA Bridge device
> * @parent: FPGA bridge device from pdev
> * @name: FPGA bridge name
> * @br_ops: pointer to structure of fpga bridge ops
> * @priv: FPGA bridge private data
> *
> - * The caller of this function is responsible for freeing the bridge with
> - * fpga_bridge_free(). Using devm_fpga_bridge_create() instead is recommended.
> - *
> - * Return: struct fpga_bridge or NULL
> + * Return: struct fpga_bridge pointer or ERR_PTR()
> */
> -struct fpga_bridge *fpga_bridge_create(struct device *parent, const char *name,
> - const struct fpga_bridge_ops *br_ops,
> - void *priv)
> +struct fpga_bridge *
> +fpga_bridge_register(struct device *parent, const char *name,
> + const struct fpga_bridge_ops *br_ops,
> + void *priv)
> {
> struct fpga_bridge *bridge;
> int id, ret;
>
> + if (!br_ops) {
> + dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> if (!name || !strlen(name)) {
> dev_err(parent, "Attempt to register with no name!\n");
> - return NULL;
> + return ERR_PTR(-EINVAL);
> }
>
> bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
> if (!bridge)
> - return NULL;
> + return ERR_PTR(-ENOMEM);
>
> id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
> - if (id < 0)
> + if (id < 0) {
> + ret = id;
> goto error_kfree;
> + }
>
> mutex_init(&bridge->mutex);
> INIT_LIST_HEAD(&bridge->node);
> @@ -350,17 +355,23 @@ struct fpga_bridge *fpga_bridge_create(struct device *parent, const char *name,
> bridge->br_ops = br_ops;
> bridge->priv = priv;
>
> - device_initialize(&bridge->dev);
> bridge->dev.groups = br_ops->groups;
> bridge->dev.class = fpga_bridge_class;
> bridge->dev.parent = parent;
> bridge->dev.of_node = parent->of_node;
> bridge->dev.id = id;
> + of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);
>
> ret = dev_set_name(&bridge->dev, "br%d", id);
> if (ret)
> goto error_device;
>
> + ret = device_register(&bridge->dev);
> + if (ret) {
> + put_device(&bridge->dev);
> + return ERR_PTR(ret);
> + }
> +
> return bridge;
>
> error_device:
> @@ -368,88 +379,7 @@ struct fpga_bridge *fpga_bridge_create(struct device *parent, const char *name,
> error_kfree:
> kfree(bridge);
>
> - return NULL;
> -}
> -EXPORT_SYMBOL_GPL(fpga_bridge_create);
> -
> -/**
> - * fpga_bridge_free - free an fpga bridge created by fpga_bridge_create()
> - * @bridge: FPGA bridge struct
> - */
> -void fpga_bridge_free(struct fpga_bridge *bridge)
> -{
> - ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
> - kfree(bridge);
> -}
> -EXPORT_SYMBOL_GPL(fpga_bridge_free);
> -
> -static void devm_fpga_bridge_release(struct device *dev, void *res)
> -{
> - struct fpga_bridge *bridge = *(struct fpga_bridge **)res;
> -
> - fpga_bridge_free(bridge);
> -}
> -
> -/**
> - * devm_fpga_bridge_create - create and init a managed struct fpga_bridge
> - * @parent: FPGA bridge device from pdev
> - * @name: FPGA bridge name
> - * @br_ops: pointer to structure of fpga bridge ops
> - * @priv: FPGA bridge private data
> - *
> - * This function is intended for use in an FPGA bridge driver's probe function.
> - * After the bridge driver creates the struct with devm_fpga_bridge_create(), it
> - * should register the bridge with fpga_bridge_register(). The bridge driver's
> - * remove function should call fpga_bridge_unregister(). The bridge struct
> - * allocated with this function will be freed automatically on driver detach.
> - * This includes the case of a probe function returning error before calling
> - * fpga_bridge_register(), the struct will still get cleaned up.
> - *
> - * Return: struct fpga_bridge or NULL
> - */
> -struct fpga_bridge
> -*devm_fpga_bridge_create(struct device *parent, const char *name,
> - const struct fpga_bridge_ops *br_ops, void *priv)
> -{
> - struct fpga_bridge **ptr, *bridge;
> -
> - ptr = devres_alloc(devm_fpga_bridge_release, sizeof(*ptr), GFP_KERNEL);
> - if (!ptr)
> - return NULL;
> -
> - bridge = fpga_bridge_create(parent, name, br_ops, priv);
> - if (!bridge) {
> - devres_free(ptr);
> - } else {
> - *ptr = bridge;
> - devres_add(parent, ptr);
> - }
> -
> - return bridge;
> -}
> -EXPORT_SYMBOL_GPL(devm_fpga_bridge_create);
> -
> -/**
> - * fpga_bridge_register - register an FPGA bridge
> - *
> - * @bridge: FPGA bridge struct
> - *
> - * Return: 0 for success, error code otherwise.
> - */
> -int fpga_bridge_register(struct fpga_bridge *bridge)
> -{
> - struct device *dev = &bridge->dev;
> - int ret;
> -
> - ret = device_add(dev);
> - if (ret)
> - return ret;
> -
> - of_platform_populate(dev->of_node, NULL, NULL, dev);
> -
> - dev_info(dev->parent, "fpga bridge [%s] registered\n", bridge->name);
> -
> - return 0;
> + return ERR_PTR(ret);
> }
> EXPORT_SYMBOL_GPL(fpga_bridge_register);
>
> @@ -475,6 +405,10 @@ EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
>
> 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 e986ed47c4ed..2d9c491f7be9 100644
> --- a/drivers/fpga/xilinx-pr-decoupler.c
> +++ b/drivers/fpga/xilinx-pr-decoupler.c
> @@ -140,22 +140,17 @@ static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
>
> clk_disable(priv->clk);
>
> - br = devm_fpga_bridge_create(&pdev->dev, priv->ipconfig->name,
> - &xlnx_pr_decoupler_br_ops, priv);
> - if (!br) {
> - err = -ENOMEM;
> - goto err_clk;
> - }
> -
> - platform_set_drvdata(pdev, br);
> -
> - err = fpga_bridge_register(br);
> - if (err) {
> + br = fpga_bridge_register(&pdev->dev, priv->ipconfig->name,
> + &xlnx_pr_decoupler_br_ops, priv);
> + if (IS_ERR(br)) {
> + err = PTR_ERR(br);
> dev_err(&pdev->dev, "unable to register %s",
> priv->ipconfig->name);
> goto err_clk;
> }
>
> + platform_set_drvdata(pdev, br);
> +
> return 0;
>
> err_clk:
> diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h
> index 6c3c28806ff1..223da48a6d18 100644
> --- a/include/linux/fpga/fpga-bridge.h
> +++ b/include/linux/fpga/fpga-bridge.h
> @@ -22,6 +22,23 @@ struct fpga_bridge_ops {
> const struct attribute_group **groups;
> };
>
> +/**
> + * struct fpga_bridge_info - collection of parameters an FPGA Bridge
> + * @name: fpga bridge name
> + * @br_ops: pointer to structure of fpga bridge ops
> + * @priv: fpga bridge private data
> + *
> + * fpga_bridge_info contains parameters for the register function. These
> + * are separated into an info structure because they some are optional
> + * others could be added to in the future. The info structure facilitates
> + * maintaining a stable API.
> + */
> +struct fpga_bridge_info {
> + const char *name;
> + const struct fpga_bridge_ops *br_ops;
> + void *priv;
> +};
> +
> /**
> * struct fpga_bridge - FPGA bridge structure
> * @name: name of low level FPGA bridge
> @@ -62,15 +79,10 @@ int of_fpga_bridge_get_to_list(struct device_node *np,
> struct fpga_image_info *info,
> struct list_head *bridge_list);
>
> -struct fpga_bridge *fpga_bridge_create(struct device *dev, const char *name,
> - const struct fpga_bridge_ops *br_ops,
> - void *priv);
> -void fpga_bridge_free(struct fpga_bridge *br);
> -int fpga_bridge_register(struct fpga_bridge *br);
> +struct fpga_bridge *
> +fpga_bridge_register(struct device *parent, const char *name,
> + const struct fpga_bridge_ops *br_ops,
> + void *priv);
> void fpga_bridge_unregister(struct fpga_bridge *br);
>
> -struct fpga_bridge
> -*devm_fpga_bridge_create(struct device *dev, const char *name,
> - const struct fpga_bridge_ops *br_ops, void *priv);
> -
> #endif /* _LINUX_FPGA_BRIDGE_H */
> --
> 2.25.1