linux-kernel - Re: [PATCHv2] fpga: stratix10-soc: remove the pre-set reconfiguration condition

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Message-ID: <de692e12-5f50-8235-5af9-2d3f5e659ddb@linux.intel.com>
Date:   Mon, 1 Jun 2020 09:44:47 -0500
From:   Richard Gong <richard.gong@...ux.intel.com>
To:     Moritz Fischer <mdf@...nel.org>
Cc:     linux-fpga@...r.kernel.org, linux-kernel@...r.kernel.org,
        dinguyen@...nel.org, Richard Gong <richard.gong@...el.com>
Subject: Re: [PATCHv2] fpga: stratix10-soc: remove the pre-set reconfiguration
 condition

Hi Moritz,


On 5/31/20 2:49 PM, Moritz Fischer wrote:
> On Fri, May 29, 2020 at 08:15:15AM -0500, Richard Gong wrote:
>> Hi Moritz,
>>
>> Sorry for asking.
>>
>> When you get chance, can you review my version 2 patch submitted on
>> 05/15/20?
>>
>> Regards,
>> Richard
>>
>> On 5/15/20 9:35 AM, richard.gong@...ux.intel.com wrote:
>>> From: Richard Gong <richard.gong@...el.com>
>>>
>>> The reconfiguration mode is pre-set by driver as the full reconfiguration.
>>> As a result, user have to change code and recompile the drivers if he or
>>> she wants to perform a partial reconfiguration. Removing the pre-set
>>> reconfiguration condition so that user can select full or partial
>>> reconfiguration via overlay device tree without recompiling the drivers.
> 
> Can you help me understand? See comment below, I'm not sure how this
> change changes the behavior.

Flag COMMAND_RECONFIG_FLAG_PARTIAL is defined in Intel service layer 
driver (include/linux/firmware/intel/stratix10-svc-client.h) and the 
default value is zero. It is obvious that COMMAND_RECONFIG_FLAG_PARTIAL 
should be set to 1 to support partial reconfiguration.

Please discard this FPGA patch, I will submit a patch on Intel service 
layer driver.

Regards,
Richard

>>>
>>> Also add an error message if the configuration request is failure.
>>>
>>> Signed-off-by: Richard Gong <richard.gong@...el.com>
>>> ---
>>> v2: define and use constant values
>>> ---
>>>    drivers/fpga/stratix10-soc.c | 9 +++++++--
>>>    1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/fpga/stratix10-soc.c b/drivers/fpga/stratix10-soc.c
>>> index 44b7c56..4d52a80 100644
>>> --- a/drivers/fpga/stratix10-soc.c
>>> +++ b/drivers/fpga/stratix10-soc.c
>>> @@ -14,9 +14,13 @@
>>>    /*
>>>     * FPGA programming requires a higher level of privilege (EL3), per the SoC
>>>     * design.
>>> + * SoC firmware supports full and partial reconfiguration.
> Consider:
> "The SoC firmware supports full and partial reconfiguration."
>>>     */
>>>    #define NUM_SVC_BUFS	4
>>>    #define SVC_BUF_SIZE	SZ_512K
>>> +#define FULL_RECONFIG_FLAG	0
>>> +#define PARTIAL_RECONFIG_FLAG	1
>>> +
>>>    /* Indicates buffer is in use if set */
>>>    #define SVC_BUF_LOCK	0
>>> @@ -182,12 +186,12 @@ static int s10_ops_write_init(struct fpga_manager *mgr,
>>>    	uint i;
>>>    	int ret;
>>> -	ctype.flags = 0;
>>>    	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
>>>    		dev_dbg(dev, "Requesting partial reconfiguration.\n");
>>> -		ctype.flags |= BIT(COMMAND_RECONFIG_FLAG_PARTIAL);
>>> +		ctype.flags = PARTIAL_RECONFIG_FLAG;
>>>    	} else {
>>>    		dev_dbg(dev, "Requesting full reconfiguration.\n");
>>> +		ctype.flags = FULL_RECONFIG_FLAG;
>>>    	}
> Am I missing something here: Doesn't this do the same as before?
> 
> Before:
> If info->flags & FPGA_MGR_PARTIAL_RECONFIG -> ctype.flags = 0 |
> BIT(COMMAND_RECONFIG_FLAG_PARTIAL) -> 1
> and ctype->flags = FULL_RECONFIG -> 0 else.
> 
> Now:
> If info->flags & FPGA_MGR_PARTIAL_RECONFIG -> ctype.flags = PARTIAL_RECONFIG_FLAG -> 1
> ctype->flags = FULL_REECONFIG_FLAG -> 0 else.
> 
> Am I missing something here? If I don't set the flag for partial
> reconfig I'd end up with full reconfiguration in both cases?
> If I do set the flag, I get partial reconfiguration in both cases?
> 
>>>    	reinit_completion(&priv->status_return_completion);
>>> @@ -210,6 +214,7 @@ static int s10_ops_write_init(struct fpga_manager *mgr,
>>>    	ret = 0;
>>>    	if (!test_and_clear_bit(SVC_STATUS_OK, &priv->status)) {
>>> +		dev_err(dev, "RECONFIG_REQUEST failed\n");
>>>    		ret = -ETIMEDOUT;
>>>    		goto init_done;
>>>    	}
>>>
> 
> Thanks,
> Moritz
>