Re: [PATCH v9 1/3] fpga: mgr: Use standard dev_release for class driver

[Tom Rix <trix@redhat.com>]

On 7/6/21 2:02 PM, Russ Weight wrote:
>
> On 7/6/21 12:04 PM, Tom Rix wrote:
>> Russ,
>>
>> My two big concerns are.
>>
>> compat_id does not belong in fpga_mgr_info, it belongs in fme_mgr_priv.
> fpga_mgr_info is a temporary structure on the stack that contains the
> parameters only long enough to pass them in and have them added to the
> fpga_manager structure. Do you have a concern about it being on the
> fpga_manager structure.

My concern is compat_id should never have been part of fpga-mgr in the 
first place.

It is dfl specific, so instead of going in a common structure, it should 
go into a dfl structure

The likely place it should go is fme_mgr_priv.

The need for 2 register functions here and in fpga-region is caused by 
carrying this dfl data around in the wrong place.

Tom

>> there are two register functions, there should be one.
> I get what you are saying. I don't really like the idea of forcing the
> complexity of the temporary structure on all callers, since only a
> couple require it, but we can do that if that is the concensus.
>
> What do others think?
>
>> On 6/30/21 6:37 PM, Russ Weight wrote:
>>> The FPGA manager 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 for the freeing of the class data structure
>>> and combines the create() and register() functions into a single
>>> register() or register_simple() function.
>>>
>>> The register() function accepts an info data structure to provide
>>> flexibility in passing optional parameters. The register_simple()
>>> function supports the current parameter list for users that don't
>>> require the use of optional parameters.
>>>
>>> The devm_fpga_mgr_register() function is retained, and the
>>> devm_fpga_mgr_register_simple() function is added.
>>>
>>> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
>>> Reviewed-by: Xu Yilun <yilun.xu@intel.com>
>>> ---
>>> v9:
>>>     - Cleaned up documentation for the FPGA Manager register functions
>>>     - Renamed fpga_mgr_register() to fpga_mgr_register_full()
>>>     - Renamed fpga_mgr_register_simple() to fpga_mgr_register()
>>>     - Renamed devm_fpga_mgr_register() to devm_fpga_mgr_register_full()
>>>     - Renamed devm_fpga_mgr_register_simple() to devm_fpga_mgr_register()
>>> v8:
>>>     - Added reviewed-by tag.
>>>     - Updated Documentation/driver-api/fpga/fpga-mgr.rst documentation.
>>> v7:
>>>     - Update the commit message to describe the new parameters for the
>>>       *fpga_mgr_register() functions and to mention the
>>>       *fpga_mgr_register_simple() functions.
>>>     - Fix function prototypes in header file to rename dev to parent.
>>>     - Make use of the PTR_ERR_OR_ZERO() macro when possible.
>>>     - Some cleanup of comments.
>>>     - Update function defintions/prototypes to apply const to the new info
>>>       parameter.
>>> v6:
>>>     - Moved FPGA manager optional parameters out of the ops structure and
>>>       back into the FPGA manager structure.
>>>     - Changed fpga_mgr_register()/devm_fpga_mgr_register() parameters to
>>>       accept an info data structure to provide flexibility in passing optional
>>>       parameters.
>>>     - Added fpga_mgr_register_simple()/devm_fpga_mgr_register_simple()
>>>       functions to support current parameters for users that don't require
>>>       the use of optional parameters.
>>> v5:
>>>     - Rebased on top of recently accepted patches.
>>>     - Removed compat_id from the fpga_mgr_register() parameter list
>>>       and added it to the fpga_manager_ops structure. This also required
>>>       dynamically allocating the dfl-fme-ops structure in order to add
>>>       the appropriate compat_id.
>>> v4:
>>>     - Added the compat_id parameter to fpga_mgr_register() and
>>>       devm_fpga_mgr_register() to ensure that the compat_id is set before
>>>       the device_register() call.
>>> v3:
>>>     - Cleaned up comment header for fpga_mgr_register()
>>>     - Fix error return on ida_simple_get() failure
>>> v2:
>>>     - Restored devm_fpga_mgr_register() functionality, adapted for the combined
>>>       create/register functionality.
>>>     - All previous callers of devm_fpga_mgr_register() will continue to call
>>>       devm_fpga_mgr_register().
>>>     - replaced unnecessary ternary operators in return statements with standard
>>>       if conditions.
>>> ---
>>>    Documentation/driver-api/fpga/fpga-mgr.rst |  34 +++-
>>>    drivers/fpga/altera-cvp.c                  |  12 +-
>>>    drivers/fpga/altera-pr-ip-core.c           |   7 +-
>>>    drivers/fpga/altera-ps-spi.c               |   9 +-
>>>    drivers/fpga/dfl-fme-mgr.c                 |  22 +--
>>>    drivers/fpga/fpga-mgr.c                    | 215 +++++++++------------
>>>    drivers/fpga/ice40-spi.c                   |   9 +-
>>>    drivers/fpga/machxo2-spi.c                 |   9 +-
>>>    drivers/fpga/socfpga-a10.c                 |  16 +-
>>>    drivers/fpga/socfpga.c                     |   9 +-
>>>    drivers/fpga/stratix10-soc.c               |  16 +-
>>>    drivers/fpga/ts73xx-fpga.c                 |   9 +-
>>>    drivers/fpga/xilinx-spi.c                  |  11 +-
>>>    drivers/fpga/zynq-fpga.c                   |  16 +-
>>>    drivers/fpga/zynqmp-fpga.c                 |   9 +-
>>>    include/linux/fpga/fpga-mgr.h              |  62 ++++--
>>>    16 files changed, 210 insertions(+), 255 deletions(-)
>>>
>>> diff --git a/Documentation/driver-api/fpga/fpga-mgr.rst b/Documentation/driver-api/fpga/fpga-mgr.rst
>>> index 4d926b452cb3..826ed8dc9210 100644
>>> --- a/Documentation/driver-api/fpga/fpga-mgr.rst
>>> +++ b/Documentation/driver-api/fpga/fpga-mgr.rst
>>> @@ -24,7 +24,7 @@ How to support a new FPGA device
>>>    --------------------------------
>>>      To add another FPGA manager, write a driver that implements a set of ops.  The
>>> -probe function calls fpga_mgr_register(), such as::
>>> +probe function calls fpga_mgr_register() or fpga_mgr_register_full(), such as::
>>>          static const struct fpga_manager_ops socfpga_fpga_ops = {
>>>            .write_init = socfpga_fpga_ops_configure_init,
>>> @@ -49,14 +49,14 @@ probe function calls fpga_mgr_register(), such as::
>>>             * them in priv
>>>             */
>>>    -        mgr = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager",
>>> -                       &socfpga_fpga_ops, priv);
>>> -        if (!mgr)
>>> -            return -ENOMEM;
>>> +        mgr = fpga_mgr_register(dev, "Altera SOCFPGA FPGA Manager",
>>> +                    &socfpga_fpga_ops, priv);
>>> +        if (IS_ERR(mgr))
>>> +            return PTR_ERR(mgr);
>>>              platform_set_drvdata(pdev, mgr);
>>>    -        return fpga_mgr_register(mgr);
>>> +        return 0;
>>>        }
>>>          static int socfpga_fpga_remove(struct platform_device *pdev)
>>> @@ -68,6 +68,11 @@ probe function calls fpga_mgr_register(), such as::
>>>            return 0;
>>>        }
>>>    +Alternatively, the probe function could call one of the resource managed
>>> +register functions, devm_fpga_mgr_register() or devm_fpga_mgr_register_full().
>>> +When these functions are used, the parameter syntax is the same, but the call
>>> +to fpga_mgr_unregister() should be removed. In the above example, the
>>> +socfpga_fpga_remove() function would not be required.
>>>      The ops will implement whatever device specific register writes are needed to
>>>    do the programming sequence for this particular FPGA.  These ops return 0 for
>>> @@ -104,8 +109,13 @@ API for implementing a new FPGA Manager driver
>>>    * ``fpga_mgr_states`` -  Values for :c:expr:`fpga_manager->state`.
>>>    * struct fpga_manager -  the FPGA manager struct
>>>    * struct fpga_manager_ops -  Low level FPGA manager driver ops
>>> -* devm_fpga_mgr_create() -  Allocate and init a manager struct
>>> -* fpga_mgr_register() -  Register an FPGA manager
>>> +* fpga_mgr_register_full() -  Create and register an FPGA manager using the
>>> +  fpga_mgr_info structure to provide the full flexibility of options
>>> +* fpga_mgr_register() -  Create and register an FPGA manager using standard
>>> +  arguments
>>> +* devm_fpga_mgr_register_full() -  Resource managed version of
>>> +  fpga_mgr_register_full()
>>> +* devm_fpga_mgr_register() -  Resource managed version of fpga_mgr_register()
>>>    * fpga_mgr_unregister() -  Unregister an FPGA manager
>>>      .. kernel-doc:: include/linux/fpga/fpga-mgr.h
>>> @@ -118,10 +128,16 @@ API for implementing a new FPGA Manager driver
>>>       :functions: fpga_manager_ops
>>>      .. kernel-doc:: drivers/fpga/fpga-mgr.c
>>> -   :functions: devm_fpga_mgr_create
>>> +   :functions: fpga_mgr_register_full
>>>      .. kernel-doc:: drivers/fpga/fpga-mgr.c
>>>       :functions: fpga_mgr_register
>>>    +.. kernel-doc:: drivers/fpga/fpga-mgr.c
>>> +   :functions: devm_fpga_mgr_register_full
>>> +
>>> +.. kernel-doc:: drivers/fpga/fpga-mgr.c
>>> +   :functions: devm_fpga_mgr_register
>>> +
>>>    .. kernel-doc:: drivers/fpga/fpga-mgr.c
>>>       :functions: fpga_mgr_unregister
>>> diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
>>> index ccf4546eff29..4ffb9da537d8 100644
>>> --- a/drivers/fpga/altera-cvp.c
>>> +++ b/drivers/fpga/altera-cvp.c
>>> @@ -652,19 +652,15 @@ static int altera_cvp_probe(struct pci_dev *pdev,
>>>        snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s @%s",
>>>             ALTERA_CVP_MGR_NAME, pci_name(pdev));
>>>    -    mgr = devm_fpga_mgr_create(&pdev->dev, conf->mgr_name,
>>> -                   &altera_cvp_ops, conf);
>>> -    if (!mgr) {
>>> -        ret = -ENOMEM;
>>> +    mgr = fpga_mgr_register(&pdev->dev, conf->mgr_name,
>>> +                &altera_cvp_ops, conf);
>>> +    if (IS_ERR(mgr)) {
>>> +        ret = PTR_ERR(mgr);
>>>            goto err_unmap;
>>>        }
>>>          pci_set_drvdata(pdev, mgr);
>>>    -    ret = fpga_mgr_register(mgr);
>>> -    if (ret)
>>> -        goto err_unmap;
>>> -
>>>        return 0;
>>>      err_unmap:
>>> diff --git a/drivers/fpga/altera-pr-ip-core.c b/drivers/fpga/altera-pr-ip-core.c
>>> index dfdf21ed34c4..be0667968d33 100644
>>> --- a/drivers/fpga/altera-pr-ip-core.c
>>> +++ b/drivers/fpga/altera-pr-ip-core.c
>>> @@ -191,11 +191,8 @@ int alt_pr_register(struct device *dev, void __iomem *reg_base)
>>>            (val & ALT_PR_CSR_STATUS_MSK) >> ALT_PR_CSR_STATUS_SFT,
>>>            (int)(val & ALT_PR_CSR_PR_START));
>>>    -    mgr = devm_fpga_mgr_create(dev, dev_name(dev), &alt_pr_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(dev, dev_name(dev), &alt_pr_ops, priv);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>    EXPORT_SYMBOL_GPL(alt_pr_register);
>>>    diff --git a/drivers/fpga/altera-ps-spi.c b/drivers/fpga/altera-ps-spi.c
>>> index 23bfd4d1ad0f..5e1e009dba89 100644
>>> --- a/drivers/fpga/altera-ps-spi.c
>>> +++ b/drivers/fpga/altera-ps-spi.c
>>> @@ -302,12 +302,9 @@ static int altera_ps_probe(struct spi_device *spi)
>>>        snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s %s",
>>>             dev_driver_string(&spi->dev), dev_name(&spi->dev));
>>>    -    mgr = devm_fpga_mgr_create(&spi->dev, conf->mgr_name,
>>> -                   &altera_ps_ops, conf);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(&spi->dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(&spi->dev, conf->mgr_name,
>>> +                     &altera_ps_ops, conf);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static const struct spi_device_id altera_ps_spi_ids[] = {
>>> diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
>>> index d5861d13b306..620e7874ab53 100644
>>> --- a/drivers/fpga/dfl-fme-mgr.c
>>> +++ b/drivers/fpga/dfl-fme-mgr.c
>>> @@ -282,7 +282,7 @@ static void fme_mgr_get_compat_id(void __iomem *fme_pr,
>>>    static int fme_mgr_probe(struct platform_device *pdev)
>>>    {
>>>        struct dfl_fme_mgr_pdata *pdata = dev_get_platdata(&pdev->dev);
>>> -    struct fpga_compat_id *compat_id;
>>> +    struct fpga_manager_info info = { 0 };
>>>        struct device *dev = &pdev->dev;
>>>        struct fme_mgr_priv *priv;
>>>        struct fpga_manager *mgr;
>>> @@ -302,20 +302,16 @@ static int fme_mgr_probe(struct platform_device *pdev)
>>>                return PTR_ERR(priv->ioaddr);
>>>        }
>>>    -    compat_id = devm_kzalloc(dev, sizeof(*compat_id), GFP_KERNEL);
>>> -    if (!compat_id)
>>> +    info.name = "DFL FME FPGA Manager";
>>> +    info.mops = &fme_mgr_ops;
>>> +    info.priv = priv;
>>> +    info.compat_id = devm_kzalloc(dev, sizeof(*info.compat_id), GFP_KERNEL);
>>> +    if (!info.compat_id)
>>>            return -ENOMEM;
>> could we limp along instead of failing ?
> The compat_id is used to verify compatibility between the static region and
> the partial reconfiguration. If there is insufficient memory for the small
> data structure, I think it is best to fail here. This is also consistent
> current implementation.
>   
>>>    -    fme_mgr_get_compat_id(priv->ioaddr, compat_id);
>>> -
>>> -    mgr = devm_fpga_mgr_create(dev, "DFL FME FPGA Manager",
>>> -                   &fme_mgr_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    mgr->compat_id = compat_id;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    fme_mgr_get_compat_id(priv->ioaddr, info.compat_id);
>>> +    mgr = devm_fpga_mgr_register_full(dev, &info);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static struct platform_driver fme_mgr_driver = {
>>> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
>>> index ecb4c3c795fa..5a913aa649fd 100644
>>> --- a/drivers/fpga/fpga-mgr.c
>>> +++ b/drivers/fpga/fpga-mgr.c
>>> @@ -550,21 +550,19 @@ void fpga_mgr_unlock(struct fpga_manager *mgr)
>>>    EXPORT_SYMBOL_GPL(fpga_mgr_unlock);
>>>      /**
>>> - * fpga_mgr_create - create and initialize an FPGA manager struct
>>> + * fpga_mgr_register_full - create and register an FPGA Manager device
>>>     * @parent:    fpga manager device from pdev
>>> - * @name:    fpga manager name
>>> - * @mops:    pointer to structure of fpga manager ops
>>> - * @priv:    fpga manager private data
>>> + * @info:    parameters for fpga manager
>>>     *
>>> - * The caller of this function is responsible for freeing the struct with
>>> - * fpga_mgr_free().  Using devm_fpga_mgr_create() instead is recommended.
>>> + * The caller of this function is responsible for calling fpga_mgr_unregister().
>>> + * Using devm_fpga_mgr_register_full() instead is recommended.
>>>     *
>>> - * Return: pointer to struct fpga_manager or NULL
>>> + * Return: pointer to struct fpga_manager pointer or ERR_PTR()
>>>     */
>>> -struct fpga_manager *fpga_mgr_create(struct device *parent, const char *name,
>>> -                     const struct fpga_manager_ops *mops,
>>> -                     void *priv)
>>> +struct fpga_manager *
>>> +fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info)
>>>    {
>>> +    const struct fpga_manager_ops *mops = info->mops;
>>>        struct fpga_manager *mgr;
>>>        int id, ret;
>>>    @@ -572,29 +570,31 @@ struct fpga_manager *fpga_mgr_create(struct device *parent, const char *name,
>>>            !mops->write_init || (!mops->write && !mops->write_sg) ||
>>>            (mops->write && mops->write_sg)) {
>>>            dev_err(parent, "Attempt to register without fpga_manager_ops\n");
>>> -        return NULL;
>>> +        return ERR_PTR(-EINVAL);
>>>        }
>>>    -    if (!name || !strlen(name)) {
>>> +    if (!info->name || !strlen(info->name)) {
>>>            dev_err(parent, "Attempt to register with no name!\n");
>>> -        return NULL;
>>> +        return ERR_PTR(-EINVAL);
>>>        }
>>>          mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
>>>        if (!mgr)
>>> -        return NULL;
>>> +        return ERR_PTR(-ENOMEM);
>>>          id = ida_simple_get(&fpga_mgr_ida, 0, 0, GFP_KERNEL);
>>> -    if (id < 0)
>>> +    if (id < 0) {
>>> +        ret = id;
>>>            goto error_kfree;
>>> +    }
>>>          mutex_init(&mgr->ref_mutex);
>>>    -    mgr->name = name;
>>> -    mgr->mops = mops;
>>> -    mgr->priv = priv;
>>> +    mgr->name = info->name;
>>> +    mgr->mops = info->mops;
>>> +    mgr->priv = info->priv;
>>> +    mgr->compat_id = info->compat_id;
>>>    -    device_initialize(&mgr->dev);
>>>        mgr->dev.class = fpga_mgr_class;
>>>        mgr->dev.groups = mops->groups;
>>>        mgr->dev.parent = parent;
>>> @@ -605,6 +605,19 @@ struct fpga_manager *fpga_mgr_create(struct device *parent, const char *name,
>>>        if (ret)
>>>            goto error_device;
>>>    +    /*
>>> +     * Initialize framework state by requesting low level driver read state
>>> +     * from device.  FPGA may be in reset mode or may have been programmed
>>> +     * by bootloader or EEPROM.
>>> +     */
>>> +    mgr->state = mgr->mops->state(mgr);
>> This is existing code, but it seems wrong.
>>
>> A side effect of state() should not be to initialize.
>>
>> An init() should be added to mops
> I think this is just capturing the state of the underlying device an
> reflecting it in the fpga-manager state? Maybe someone else can comment
> on this. It seems outside the scope of these patches.
>
>>> +
>>> +    ret = device_register(&mgr->dev);
>>> +    if (ret) {
>>> +        put_device(&mgr->dev);
>>> +        return ERR_PTR(ret);
>>> +    }
>>> +
>>>        return mgr;
>>>      error_device:
>>> @@ -612,96 +625,36 @@ struct fpga_manager *fpga_mgr_create(struct device *parent, const char *name,
>>>    error_kfree:
>>>        kfree(mgr);
>>>    -    return NULL;
>>> +    return ERR_PTR(ret);
>>>    }
>>> -EXPORT_SYMBOL_GPL(fpga_mgr_create);
>>> +EXPORT_SYMBOL_GPL(fpga_mgr_register_full);
>>>      /**
>>> - * fpga_mgr_free - free an FPGA manager created with fpga_mgr_create()
>>> - * @mgr:    fpga manager struct
>>> - */
>>> -void fpga_mgr_free(struct fpga_manager *mgr)
>>> -{
>>> -    ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
>>> -    kfree(mgr);
>>> -}
>>> -EXPORT_SYMBOL_GPL(fpga_mgr_free);
>>> -
>>> -static void devm_fpga_mgr_release(struct device *dev, void *res)
>>> -{
>>> -    struct fpga_mgr_devres *dr = res;
>>> -
>>> -    fpga_mgr_free(dr->mgr);
>>> -}
>>> -
>>> -/**
>>> - * devm_fpga_mgr_create - create and initialize a managed FPGA manager struct
>>> + * fpga_mgr_register - create and register an FPGA Manager device
>>>     * @parent:    fpga manager device from pdev
>>>     * @name:    fpga manager name
>>>     * @mops:    pointer to structure of fpga manager ops
>>>     * @priv:    fpga manager private data
>>>     *
>>> - * This function is intended for use in an FPGA manager driver's probe function.
>>> - * After the manager driver creates the manager struct with
>>> - * devm_fpga_mgr_create(), it should register it with fpga_mgr_register().  The
>>> - * manager driver's remove function should call fpga_mgr_unregister().  The
>>> - * manager 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_mgr_register(), the struct will still get cleaned up.
>>> + * The caller of this function is responsible for calling fpga_mgr_unregister().
>>> + * Using devm_fpga_mgr_register() instead is recommended. This simple
>>> + * version of the register function should be sufficient for most users. The
>>> + * fpga_mgr_register_full() function is available for users that need to pass
>>> + * additional, optional parameters.
>>>     *
>>> - * Return: pointer to struct fpga_manager or NULL
>>> + * Return: pointer to struct fpga_manager pointer or ERR_PTR()
>>>     */
>>> -struct fpga_manager *devm_fpga_mgr_create(struct device *parent, const char *name,
>>> -                      const struct fpga_manager_ops *mops,
>>> -                      void *priv)
>>> +struct fpga_manager *
>>> +fpga_mgr_register(struct device *parent, const char *name,
>>> +          const struct fpga_manager_ops *mops, void *priv)
>>>    {
>>> -    struct fpga_mgr_devres *dr;
>>> +    struct fpga_manager_info info = { 0 };
>>>    -    dr = devres_alloc(devm_fpga_mgr_release, sizeof(*dr), GFP_KERNEL);
>>> -    if (!dr)
>>> -        return NULL;
>>> +    info.name = name;
>>> +    info.mops = mops;
>>> +    info.priv = priv;
>>>    -    dr->mgr = fpga_mgr_create(parent, name, mops, priv);
>>> -    if (!dr->mgr) {
>>> -        devres_free(dr);
>>> -        return NULL;
>>> -    }
>>> -
>>> -    devres_add(parent, dr);
>>> -
>>> -    return dr->mgr;
>>> -}
>>> -EXPORT_SYMBOL_GPL(devm_fpga_mgr_create);
>>> -
>>> -/**
>>> - * fpga_mgr_register - register an FPGA manager
>>> - * @mgr: fpga manager struct
>>> - *
>>> - * Return: 0 on success, negative error code otherwise.
>>> - */
>>> -int fpga_mgr_register(struct fpga_manager *mgr)
>>> -{
>>> -    int ret;
>>> -
>>> -    /*
>>> -     * Initialize framework state by requesting low level driver read state
>>> -     * from device.  FPGA may be in reset mode or may have been programmed
>>> -     * by bootloader or EEPROM.
>>> -     */
>>> -    mgr->state = mgr->mops->state(mgr);
>>> -
>>> -    ret = device_add(&mgr->dev);
>>> -    if (ret)
>>> -        goto error_device;
>>> -
>>> -    dev_info(&mgr->dev, "%s registered\n", mgr->name);
>>> -
>>> -    return 0;
>>> -
>>> -error_device:
>>> -    ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
>>> -
>>> -    return ret;
>>> +    return fpga_mgr_register_full(parent, &info);
>>>    }
>>>    EXPORT_SYMBOL_GPL(fpga_mgr_register);
>>>    @@ -726,14 +679,6 @@ void fpga_mgr_unregister(struct fpga_manager *mgr)
>>>    }
>>>    EXPORT_SYMBOL_GPL(fpga_mgr_unregister);
>>>    -static int fpga_mgr_devres_match(struct device *dev, void *res,
>>> -                 void *match_data)
>>> -{
>>> -    struct fpga_mgr_devres *dr = res;
>>> -
>>> -    return match_data == dr->mgr;
>>> -}
>>> -
>>>    static void devm_fpga_mgr_unregister(struct device *dev, void *res)
>>>    {
>>>        struct fpga_mgr_devres *dr = res;
>>> @@ -742,45 +687,67 @@ static void devm_fpga_mgr_unregister(struct device *dev, void *res)
>>>    }
>>>      /**
>>> - * devm_fpga_mgr_register - resource managed variant of fpga_mgr_register()
>>> - * @dev: managing device for this FPGA manager
>>> - * @mgr: fpga manager struct
>>> + * devm_fpga_mgr_register_full - resource managed variant of fpga_mgr_register()
>>> + * @parent:    fpga manager device from pdev
>>> + * @info:    parameters for fpga manager
>>>     *
>>> - * This is the devres variant of fpga_mgr_register() for which the unregister
>>> + * This is the devres variant of fpga_mgr_register_full() for which the unregister
>>>     * function will be called automatically when the managing device is detached.
>>>     */
>>> -int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr)
>>> +struct fpga_manager *
>>> +devm_fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info)
>>>    {
>>>        struct fpga_mgr_devres *dr;
>>> -    int ret;
>>> -
>>> -    /*
>>> -     * Make sure that the struct fpga_manager * that is passed in is
>>> -     * managed itself.
>>> -     */
>>> -    if (WARN_ON(!devres_find(dev, devm_fpga_mgr_release,
>>> -                 fpga_mgr_devres_match, mgr)))
>>> -        return -EINVAL;
>>> +    struct fpga_manager *mgr;
>>>          dr = devres_alloc(devm_fpga_mgr_unregister, sizeof(*dr), GFP_KERNEL);
>>>        if (!dr)
>>> -        return -ENOMEM;
>>> +        return ERR_PTR(-ENOMEM);
>>>    -    ret = fpga_mgr_register(mgr);
>>> -    if (ret) {
>>> +    mgr = fpga_mgr_register_full(parent, info);
>>> +    if (IS_ERR(mgr)) {
>>>            devres_free(dr);
>>> -        return ret;
>>> +        return mgr;
>>>        }
>>>          dr->mgr = mgr;
>>> -    devres_add(dev, dr);
>>> +    devres_add(parent, dr);
>>>    -    return 0;
>>> +    return mgr;
>>> +}
>>> +EXPORT_SYMBOL_GPL(devm_fpga_mgr_register_full);
>>> +
>>> +/**
>>> + * devm_fpga_mgr_register - resource managed variant of fpga_mgr_register()
>>> + * @parent:    fpga manager device from pdev
>>> + * @name:    fpga manager name
>>> + * @mops:    pointer to structure of fpga manager ops
>>> + * @priv:    fpga manager private data
>>> + *
>>> + * This is the devres variant of fpga_mgr_register() for which the
>>> + * unregister function will be called automatically when the managing
>>> + * device is detached.
>>> + */
>>> +struct fpga_manager *
>>> +devm_fpga_mgr_register(struct device *parent, const char *name,
>>> +               const struct fpga_manager_ops *mops, void *priv)
>>> +{
>>> +    struct fpga_manager_info info = { 0 };
>>> +
>>> +    info.name = name;
>>> +    info.mops = mops;
>>> +    info.priv = priv;
>>> +
>>> +    return devm_fpga_mgr_register_full(parent, &info);
>>>    }
>>>    EXPORT_SYMBOL_GPL(devm_fpga_mgr_register);
>>>      static void fpga_mgr_dev_release(struct device *dev)
>>>    {
>>> +    struct fpga_manager *mgr = to_fpga_manager(dev);
>>> +
>>> +    ida_simple_remove(&fpga_mgr_ida, mgr->dev.id);
>>> +    kfree(mgr);
>>>    }
>>>      static int __init fpga_mgr_class_init(void)
>>> diff --git a/drivers/fpga/ice40-spi.c b/drivers/fpga/ice40-spi.c
>>> index 69dec5af23c3..b7591912248f 100644
>>> --- a/drivers/fpga/ice40-spi.c
>>> +++ b/drivers/fpga/ice40-spi.c
>>> @@ -178,12 +178,9 @@ static int ice40_fpga_probe(struct spi_device *spi)
>>>            return ret;
>>>        }
>>>    -    mgr = devm_fpga_mgr_create(dev, "Lattice iCE40 FPGA Manager",
>>> -                   &ice40_fpga_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager",
>>> +                     &ice40_fpga_ops, priv);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static const struct of_device_id ice40_fpga_of_match[] = {
>>> diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
>>> index 1afb41aa20d7..8469dfb5dd21 100644
>>> --- a/drivers/fpga/machxo2-spi.c
>>> +++ b/drivers/fpga/machxo2-spi.c
>>> @@ -366,12 +366,9 @@ static int machxo2_spi_probe(struct spi_device *spi)
>>>            return -EINVAL;
>>>        }
>>>    -    mgr = devm_fpga_mgr_create(dev, "Lattice MachXO2 SPI FPGA Manager",
>>> -                   &machxo2_ops, spi);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(dev, "Lattice MachXO2 SPI FPGA Manager",
>>> +                     &machxo2_ops, spi);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      #ifdef CONFIG_OF
>>> diff --git a/drivers/fpga/socfpga-a10.c b/drivers/fpga/socfpga-a10.c
>>> index 573d88bdf730..ac8e89b8a5cc 100644
>>> --- a/drivers/fpga/socfpga-a10.c
>>> +++ b/drivers/fpga/socfpga-a10.c
>>> @@ -508,19 +508,15 @@ static int socfpga_a10_fpga_probe(struct platform_device *pdev)
>>>            return -EBUSY;
>>>        }
>>>    -    mgr = devm_fpga_mgr_create(dev, "SoCFPGA Arria10 FPGA Manager",
>>> -                   &socfpga_a10_fpga_mgr_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    platform_set_drvdata(pdev, mgr);
>>> -
>>> -    ret = fpga_mgr_register(mgr);
>>> -    if (ret) {
>>> +    mgr = fpga_mgr_register(dev, "SoCFPGA Arria10 FPGA Manager",
>>> +                &socfpga_a10_fpga_mgr_ops, priv);
>>> +    if (IS_ERR(mgr)) {
>>>            clk_disable_unprepare(priv->clk);
>>> -        return ret;
>>> +        return PTR_ERR(mgr);
>>>        }
>>>    +    platform_set_drvdata(pdev, mgr);
>>> +
>>>        return 0;
>>>    }
>>>    diff --git a/drivers/fpga/socfpga.c b/drivers/fpga/socfpga.c
>>> index 1f467173fc1f..7e0741f99696 100644
>>> --- a/drivers/fpga/socfpga.c
>>> +++ b/drivers/fpga/socfpga.c
>>> @@ -571,12 +571,9 @@ static int socfpga_fpga_probe(struct platform_device *pdev)
>>>        if (ret)
>>>            return ret;
>>>    -    mgr = devm_fpga_mgr_create(dev, "Altera SOCFPGA FPGA Manager",
>>> -                   &socfpga_fpga_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(dev, "Altera SOCFPGA FPGA Manager",
>>> +                     &socfpga_fpga_ops, priv);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      #ifdef CONFIG_OF
>>> diff --git a/drivers/fpga/stratix10-soc.c b/drivers/fpga/stratix10-soc.c
>>> index a2cea500f7cc..9155e888a133 100644
>>> --- a/drivers/fpga/stratix10-soc.c
>>> +++ b/drivers/fpga/stratix10-soc.c
>>> @@ -425,18 +425,11 @@ static int s10_probe(struct platform_device *pdev)
>>>          init_completion(&priv->status_return_completion);
>>>    -    mgr = fpga_mgr_create(dev, "Stratix10 SOC FPGA Manager",
>>> -                  &s10_ops, priv);
>>> -    if (!mgr) {
>>> -        dev_err(dev, "unable to create FPGA manager\n");
>>> -        ret = -ENOMEM;
>>> -        goto probe_err;
>>> -    }
>>> -
>>> -    ret = fpga_mgr_register(mgr);
>>> -    if (ret) {
>>> +    mgr = fpga_mgr_register(dev, "Stratix10 SOC FPGA Manager",
>>> +                &s10_ops, priv);
>>> +    if (IS_ERR(mgr)) {
>>>            dev_err(dev, "unable to register FPGA manager\n");
>>> -        fpga_mgr_free(mgr);
>>> +        ret = PTR_ERR(mgr);
>>>            goto probe_err;
>>>        }
>>>    @@ -454,7 +447,6 @@ static int s10_remove(struct platform_device *pdev)
>>>        struct s10_priv *priv = mgr->priv;
>>>          fpga_mgr_unregister(mgr);
>>> -    fpga_mgr_free(mgr);
>>>        stratix10_svc_free_channel(priv->chan);
>>>          return 0;
>>> diff --git a/drivers/fpga/ts73xx-fpga.c b/drivers/fpga/ts73xx-fpga.c
>>> index 101f016c6ed8..fd52de20ddb2 100644
>>> --- a/drivers/fpga/ts73xx-fpga.c
>>> +++ b/drivers/fpga/ts73xx-fpga.c
>>> @@ -122,12 +122,9 @@ static int ts73xx_fpga_probe(struct platform_device *pdev)
>>>        if (IS_ERR(priv->io_base))
>>>            return PTR_ERR(priv->io_base);
>>>    -    mgr = devm_fpga_mgr_create(kdev, "TS-73xx FPGA Manager",
>>> -                   &ts73xx_fpga_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(kdev, mgr);
>>> +    mgr = devm_fpga_mgr_register(kdev, "TS-73xx FPGA Manager",
>>> +                     &ts73xx_fpga_ops, priv);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static struct platform_driver ts73xx_fpga_driver = {
>>> diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
>>> index fee4d0abf6bf..db23626f9ab2 100644
>>> --- a/drivers/fpga/xilinx-spi.c
>>> +++ b/drivers/fpga/xilinx-spi.c
>>> @@ -247,13 +247,10 @@ static int xilinx_spi_probe(struct spi_device *spi)
>>>            return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
>>>                         "Failed to get DONE gpio\n");
>>>    -    mgr = devm_fpga_mgr_create(&spi->dev,
>>> -                   "Xilinx Slave Serial FPGA Manager",
>>> -                   &xilinx_spi_ops, conf);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(&spi->dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(&spi->dev,
>>> +                     "Xilinx Slave Serial FPGA Manager",
>>> +                     &xilinx_spi_ops, conf);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static const struct of_device_id xlnx_spi_of_match[] = {
>>> diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
>>> index 9b75bd4f93d8..426aa34c6a0d 100644
>>> --- a/drivers/fpga/zynq-fpga.c
>>> +++ b/drivers/fpga/zynq-fpga.c
>>> @@ -609,20 +609,16 @@ static int zynq_fpga_probe(struct platform_device *pdev)
>>>          clk_disable(priv->clk);
>>>    -    mgr = devm_fpga_mgr_create(dev, "Xilinx Zynq FPGA Manager",
>>> -                   &zynq_fpga_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    platform_set_drvdata(pdev, mgr);
>>> -
>>> -    err = fpga_mgr_register(mgr);
>>> -    if (err) {
>>> +    mgr = fpga_mgr_register(dev, "Xilinx Zynq FPGA Manager",
>>> +                &zynq_fpga_ops, priv);
>>> +    if (IS_ERR(mgr)) {
>>>            dev_err(dev, "unable to register FPGA manager\n");
>>>            clk_unprepare(priv->clk);
>>> -        return err;
>>> +        return PTR_ERR(mgr);
>>>        }
>>>    +    platform_set_drvdata(pdev, mgr);
>>> +
>>>        return 0;
>>>    }
>>>    diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
>>> index 125743c9797f..975bdc4d0a65 100644
>>> --- a/drivers/fpga/zynqmp-fpga.c
>>> +++ b/drivers/fpga/zynqmp-fpga.c
>>> @@ -102,12 +102,9 @@ static int zynqmp_fpga_probe(struct platform_device *pdev)
>>>          priv->dev = dev;
>>>    -    mgr = devm_fpga_mgr_create(dev, "Xilinx ZynqMP FPGA Manager",
>>> -                   &zynqmp_fpga_ops, priv);
>>> -    if (!mgr)
>>> -        return -ENOMEM;
>>> -
>>> -    return devm_fpga_mgr_register(dev, mgr);
>>> +    mgr = devm_fpga_mgr_register(dev, "Xilinx ZynqMP FPGA Manager",
>>> +                     &zynqmp_fpga_ops, priv);
>>> +    return PTR_ERR_OR_ZERO(mgr);
>>>    }
>>>      static const struct of_device_id zynqmp_fpga_of_match[] = {
>>> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
>>> index 474c1f506307..ac3ddaf2903c 100644
>>> --- a/include/linux/fpga/fpga-mgr.h
>>> +++ b/include/linux/fpga/fpga-mgr.h
>>> @@ -105,6 +105,36 @@ struct fpga_image_info {
>>>    #endif
>>>    };
>>>    +/**
>>> + * struct fpga_compat_id - id for compatibility check
>>> + *
>>> + * @id_h: high 64bit of the compat_id
>>> + * @id_l: low 64bit of the compat_id
>>> + */
>>> +struct fpga_compat_id {
>>> +    u64 id_h;
>>> +    u64 id_l;
>>> +};
>>> +
>> There are two register functions are to handle this dfl only structure.
>>
>> This really needs to be moved fme_mgr_priv.
>>
>>> +/**
>>> + * struct fpga_manager_info - collection of parameters for an FPGA Manager
>>> + * @name: fpga manager name
>>> + * @compat_id: FPGA manager id for compatibility check.
>>> + * @mops: pointer to structure of fpga manager ops
>>> + * @priv: fpga manager private data
>>> + *
>>> + * fpga_manager_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_manager_info {
>>> +    const char *name;
>>> +    struct fpga_compat_id *compat_id;
>>> +    const struct fpga_manager_ops *mops;
>>> +    void *priv;
>>> +};
>>> +
>>>    /**
>>>     * struct fpga_manager_ops - ops for low level fpga manager drivers
>>>     * @initial_header_size: Maximum number of bytes that should be passed into write_init
>>> @@ -143,17 +173,6 @@ struct fpga_manager_ops {
>>>    #define FPGA_MGR_STATUS_IP_PROTOCOL_ERR        BIT(3)
>>>    #define FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR    BIT(4)
>>>    -/**
>>> - * struct fpga_compat_id - id for compatibility check
>>> - *
>>> - * @id_h: high 64bit of the compat_id
>>> - * @id_l: low 64bit of the compat_id
>>> - */
>>> -struct fpga_compat_id {
>>> -    u64 id_h;
>>> -    u64 id_l;
>>> -};
>>> -
>>>    /**
>>>     * struct fpga_manager - fpga manager structure
>>>     * @name: name of low level fpga manager
>>> @@ -191,17 +210,18 @@ struct fpga_manager *fpga_mgr_get(struct device *dev);
>>>      void fpga_mgr_put(struct fpga_manager *mgr);
>>>    -struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name,
>>> -                     const struct fpga_manager_ops *mops,
>>> -                     void *priv);
>>> -void fpga_mgr_free(struct fpga_manager *mgr);
>> removing these should cause any oot driver to fail to load.
>>
>> so an oops is unlikely.
>>
>> I'm ok with with api change.
>>
>>> -int fpga_mgr_register(struct fpga_manager *mgr);
>>> -void fpga_mgr_unregister(struct fpga_manager *mgr);
>>> +struct fpga_manager *
>>> +fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info);
>>>    -int devm_fpga_mgr_register(struct device *dev, struct fpga_manager *mgr);
>>> +struct fpga_manager *
>>> +fpga_mgr_register(struct device *parent, const char *name,
>>> +          const struct fpga_manager_ops *mops, void *priv);
>> having 2 ways to do the same thing is not great.
>>
>> this should be reduced down to 1.
>>
>> My preference is for the *info one as it's api will be durable.
> I would like to see if other's agree.
>
>> Tom
>>
>>> +void fpga_mgr_unregister(struct fpga_manager *mgr);
>>>    -struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name,
>>> -                      const struct fpga_manager_ops *mops,
>>> -                      void *priv);
>>> +struct fpga_manager *
>>> +devm_fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info);
>>> +struct fpga_manager *
>>> +devm_fpga_mgr_register(struct device *parent, const char *name,
>>> +               const struct fpga_manager_ops *mops, void *priv);
>>>      #endif /*_LINUX_FPGA_MGR_H */