linux-kernel - Re: [RFC 4/8] doc: fpga-mgr: separate getting/locking FPGA manager

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Date:   Fri, 17 Feb 2017 09:52:03 -0800
From:   Moritz Fischer <mdf@...nel.org>
To:     Alan Tull <atull@...nel.org>
Cc:     Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-fpga@...r.kernel.org
Subject: Re: [RFC 4/8] doc: fpga-mgr: separate getting/locking FPGA manager

Alan,

small nits inline

On Wed, Feb 15, 2017 at 8:14 AM, Alan Tull <atull@...nel.org> wrote:
> Document that getting a reference to a FPGA Manager has been
> separated from locking the FPGA Mangager for use.
>
> fpga_mgr_lock/unlock functions get/release mutex.
>
> of_fpga_mgr_get, fpga_mgr_get, and fpga_mgr_put no longer lock
> the FPGA manager mutex.
>
> This makes it more straigtforward to save a reference to
> a FPGA manager and only attempting to lock it when programming
> the FPGA.
>
> Signed-off-by: Alan Tull <atull@...nel.org>
Acked-by: Moritz Fischer <mdf@...nel.org>

> ---
>  Documentation/fpga/fpga-mgr.txt | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt
> index 78f197f..06d5d5b 100644
> --- a/Documentation/fpga/fpga-mgr.txt
> +++ b/Documentation/fpga/fpga-mgr.txt
> @@ -53,13 +53,26 @@ To get/put a reference to a FPGA manager:
>         struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
>         struct fpga_manager *fpga_mgr_get(struct device *dev);
>
> -Given a DT node or device, get an exclusive reference to a FPGA manager.
> +Given a DT node or device, get an reference to a FPGA manager.  Pointer

Nits: get *a* reference, 'A' pointer or 'The' pointer.

> +can be saved until you are ready to program the FPGA.
>
>         void fpga_mgr_put(struct fpga_manager *mgr);
>
>  Release the reference.
>
>
> +To get exclusive control of a FPGA manager:
> +-------------------------------------------
> +
> +       int fpga_mgr_lock(struct fpga_magager *mgr);
> +
> +Call fpga_mgr_lock and verify that it returns 0 before attempting to
> +program the FPGA.
> +
> +       void fpga_mgr_unlock(struct fpga_magager *mgr);
> +
> +Call fpga_mgr_unlock when done programming the FPGA.
> +
>  To register or unregister the low level FPGA-specific driver:
>  -------------------------------------------------------------
>
> @@ -95,11 +108,13 @@ int ret;
>
>  /* Get exclusive control of FPGA manager */
>  struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
> +ret = fpga_mgr_lock(mgr);
>
>  /* Load the buffer to the FPGA */
>  ret = fpga_mgr_buf_load(mgr, &info, buf, count);
>
>  /* Release the FPGA manager */
> +fpga_mgr_unlock(mgr);
>  fpga_mgr_put(mgr);
>
>
> @@ -124,11 +139,13 @@ int ret;
>
>  /* Get exclusive control of FPGA manager */
>  struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
> +ret = fpga_mgr_lock(mgr);
>
>  /* Get the firmware image (path) and load it to the FPGA */
>  ret = fpga_mgr_firmware_load(mgr, &info, path);
>
>  /* Release the FPGA manager */
> +fpga_mgr_unlock(mgr);
>  fpga_mgr_put(mgr);
>
>
> --
> 2.7.4
>

Cheers,

Moritz