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From: "Li, Yi" <yi1.li@linux.intel.com>
To: Alan Tull <atull@kernel.org>,
	Moritz Fischer <moritz.fischer@ettus.com>,
	Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: linux-kernel@vger.kernel.org, linux-fpga@vger.kernel.org
Subject: Re: [RFC 4/8] doc: fpga-mgr: separate getting/locking FPGA manager
Date: Fri, 17 Feb 2017 11:14:02 -0600	[thread overview]
Message-ID: <20c28527-8a58-7aa0-489c-5bef7228a159@linux.intel.com> (raw)
In-Reply-To: <1487175261-7051-5-git-send-email-atull@kernel.org>

hi Alan


On 2/15/2017 10:14 AM, Alan Tull 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.

New to the FPGA world, but I like the idea of shorter lock. Separating 
the lock from fpga_mgr_get will give underline FPGA device drivers more 
flexibility to acquire the mgr pointer.
One newbie question, since the underline FPGA device driver does the 
fpga_mgr_register during probe, each manager instance belongs to that 
FPGA device only. What's the use to keep tracking the usage reference 
with fpga_mgr_put/get function, or is it enough to increase/decrease dev 
reference count in fpga_mgr_register/unregister function?

Thanks,
Yi

>
> Signed-off-by: Alan Tull <atull@kernel.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
> +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);
>   
>   

  reply	other threads:[~2017-02-17 17:14 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-15 16:14 FPGA Region enhancements and fixes Alan Tull
2017-02-15 16:14 ` [RFC 1/8] fpga-mgr: add a single function for fpga loading methods Alan Tull
2017-02-16  0:36   ` matthew.gerlach
2017-02-15 16:14 ` [RFC 2/8] fpga-region: support more than one overlay per FPGA region Alan Tull
2017-02-16 16:50   ` matthew.gerlach
2017-02-16 17:35     ` Alan Tull
2017-02-15 16:14 ` [RFC 3/8] fpga-bridge: add non-dt support Alan Tull
2017-02-15 16:14 ` [RFC 4/8] doc: fpga-mgr: separate getting/locking FPGA manager Alan Tull
2017-02-17 17:14   ` Li, Yi [this message]
2017-02-17 21:55     ` Alan Tull
2017-02-17 17:52   ` Moritz Fischer
2017-02-17 22:02     ` Alan Tull
2017-02-15 16:14 ` [RFC 5/8] " Alan Tull
2017-02-15 16:14 ` [RFC 6/8] fpga-region: separate out common code to allow non-dt support Alan Tull
2017-02-15 16:14 ` [RFC 7/8] fpga-region: add sysfs interface Alan Tull
2017-02-15 17:21   ` Jason Gunthorpe
2017-02-15 17:46     ` Alan Tull
2017-02-15 17:55       ` Moritz Fischer
2017-02-15 18:06       ` Jason Gunthorpe
2017-02-15 18:23         ` Alan Tull
2017-02-15 18:31           ` Moritz Fischer
2017-02-15 19:49           ` Jason Gunthorpe
2017-02-15 22:49             ` Alan Tull
2017-02-15 23:07               ` Jason Gunthorpe
2017-02-15 20:07           ` matthew.gerlach
2017-02-15 20:37             ` Jason Gunthorpe
2017-02-15 20:54               ` Moritz Fischer
2017-02-15 21:15                 ` Jason Gunthorpe
2017-02-15 21:36                   ` Moritz Fischer
2017-02-15 22:42                     ` Alan Tull
2017-02-16  0:16                       ` Moritz Fischer
2017-02-16 17:47                         ` Alan Tull
2017-02-16 17:56                           ` Jason Gunthorpe
2017-02-16 18:11                             ` Moritz Fischer
2017-02-17 22:28                 ` Yves Vandervennet
2017-02-18  2:30                   ` Moritz Fischer
2017-02-18 12:45                     ` Nadathur, Sundar
2017-02-18 20:10                       ` Alan Tull
2017-02-18 20:45                         ` Moritz Fischer
2017-02-19 15:00                           ` Alan Tull
2017-02-19 23:16                             ` Alan Tull
2017-02-20 23:49                               ` Moritz Fischer
2017-02-21 18:33                                 ` Alan Tull
2017-02-22  3:13                                   ` Nadathur, Sundar
2017-02-22  3:49                                     ` Moritz Fischer
2017-02-22  5:12                                       ` Jason Gunthorpe
2017-02-22  5:38                                         ` Moritz Fischer
2017-02-22  5:46                                           ` Nadathur, Sundar
2017-02-22  6:05                                             ` Moritz Fischer
2017-02-22 16:44                                               ` Jason Gunthorpe
2017-02-22 17:50                                                 ` Moritz Fischer
2017-02-22 17:54                                                   ` Jason Gunthorpe
2017-02-22 17:57                                                     ` Moritz Fischer
2017-02-22 16:33                                           ` Alan Tull
2017-02-22 16:44                                             ` Moritz Fischer
2017-02-22 16:52                                               ` Alan Tull
2017-02-27 20:09                                   ` Alan Tull
2017-02-27 22:49                                     ` Moritz Fischer
2017-02-28  0:04                                       ` matthew.gerlach
2017-02-15 21:20         ` Anatolij Gustschin
2017-02-15 16:14 ` [RFC 8/8] doc: fpga: add sysfs document for fpga region Alan Tull
2017-02-28 17:35 ` FPGA Region enhancements and fixes Alan Tull
2017-02-28 22:03   ` Alan Tull

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